Category Archives: Anti-cancer

Phenolics

Cancer: Prostate

Action: Chemo-preventive, anti-oxidant, modulate insulin-like growth factor-I (IGF-I)

Natural phenolic compounds play an important role in cancer prevention and treatment. Phenolic compounds from medicinal herbs and dietary plants include phenolic acids, flavonoids, tannins, stilbenes, curcuminoids, coumarins, lignans, quinones, and others. Various bioactivities of phenolic compounds are responsible for their chemo-preventive properties (e.g. anti-oxidant, anti-carcinogenic, or anti-mutagenic and anti-inflammatory effects) and also contribute to their inducing apoptosis by arresting cell-cycle, regulating carcinogen metabolism and ontogenesis expression, inhibiting DNA binding and cell adhesion, migration, proliferation or differentiation, and blocking signaling pathways. A review by Huang et al., (2010) covers the most recent literature to summarize structural categories and molecular anti-cancer mechanisms of phenolic compounds from medicinal herbs and dietary plants (Huang, Cai, & Zhang., 2010).

Phenolics are compounds possessing one or more aromatic rings bearing one or more hydroxyl groups with over 8,000 structural variants, and generally are categorized as phenolic acids and analogs, flavonoids, tannins, stilbenes, curcuminoids, coumarins, lignans, quinones, and others based on the number of phenolic rings and of the structural elements that link these rings (Fresco et al., 2006).

Phenolic Acids

Phenolic acids are a major class of phenolic compounds, widely occurring in the plant kingdom.   Predominant phenolic acids include hydroxybenzoic acids (e.g. gallic acid, p-hydroxybenzoic acid, protocatechuic acid, vanillic acid, and syringic acid) and hydroxycinnamic acids (e.g. ferulic acid, caffeic acid, p-coumaric acid, chlorogenic acid, and sinapic acid). Natural phenolic acids, either occurring in the free or conjugated forms, usually appear as esters or amides.

Due to their structural similarity, several other polyphenols are considered as phenolic acid analogs such as capsaicin, rosmarinic acid, gingerol, gossypol, paradol, tyrosol, hydroxytyrosol, ellagic acid, cynarin, and salvianolic acid B (Fresco et al., 2006; Han et al., 2007).

Gallic acid is widely distributed in medicinal herbs, such as Barringtonia racemosa, Cornus officinalis, Cassia auriculata, Polygonum aviculare, Punica granatum, Rheum officinale, Rhus chinensis, Sanguisorba officinalis, and Terminalia chebula as well as dietary spices, for example, thyme and clove. Other hydroxybenzoic acids are also ubiquitous in medicinal herbs and dietary plants (spices, fruits, vegetables).

For example, Dolichos biflorus, Feronia elephantum, and Paeonia lactiflora contain hydroxybenzoic acid; Cinnamomum cassia, Lawsonia inermis, dill, grape, and star anise possess protocatechuic acid; Foeniculum vulgare, Ipomoea turpethum, and Picrorhiza scrophulariiflora have vanillic acid; Ceratostigma willmottianum and sugarcane straw possess syringic acid (Cai et al., 2004; Shan et al., 2005; Sampietro & Vattuone, 2006; Stagos et al., 2006; Surveswaran et al., 2007).

Ferulic, caffeic, and p-coumaric acid are present in many medicinal herbs and dietary spices, fruits, vegetables, and grains (Cai et al., 2004). Wheat bran is a good source of ferulic acids. Free, soluble-conjugated, and bound ferulic acids in grains are present in the ratio of 0.1:1:100. Red fruits (blueberry, blackberry, chokeberry, strawberry, red raspberry, sweet cherry, sour cherry, elderberry, black currant, and red currant) are rich in hydroxycinnamic acids (caffeic, ferulic, p-coumaric acid) and p-hydroxybenzoic, ellagic acid, which contribute to their anti-oxidant activity (Jakobek et al., 2007).

Chlorogenic acids are the ester of caffeic acids and are the substrate for enzymatic oxidation leading to browning, particularly in apples and potatoes. Chlorogenic acid is a major phenolic acid from medicinal plants especially in the species of Apocynaceae and Asclepiadaceae (Huang et al., 2007).

Salvianolic acid B is a major water-soluble polyphenolic acid extracted from Radix salviae miltiorrhizae, which is a common herbal medicine clinically used as an anti-oxidant agent for thousands of years in China. There are 9 activated phenolic hydroxyl groups that may be responsible for the release of active hydrogen to block lipid peroxidation reaction. Rosmarinic acid is an anti-oxidant phenolic compound, which is found in many dietary spices such as mint, sweet basil, oregano, rosemary, sage, and thyme.

Gossypol, a polyphenolic aldehyde, derived from the seeds of the cotton plant (genus Gossypium, family Malvaceae), has contraceptive activity and can cause hypokalemia in some men. Gingerol, a phenolic substance, is responsible for the spicy taste of ginger.

Polyphenols

Polyphenols are a structural class of mainly natural, organic chemicals characterized by the presence of large multiples of phenol structural units. The number and characteristics of these phenol structures underlie the unique physical, chemical, and biological (metabolic, toxic, therapeutic, etc.) properties of particular members of the class. They may be broadly classified as phenolic acids, flavonoids, stilbenes, and lignans (Manach et al., 2004).

Initial evidence on cancer came from epidemiologic studies suggesting that a diet that includes regular consumption of fruits and vegetables (rich in polyphenols) significantly reduces the risk of many cancers.

Polyphenolic cancer action can be attributed not only to their ability to act as anti-oxidants but also to their ability to interact with basic cellular mechanisms. Such interactions include interference with membrane and intracellular receptors, modulation of signaling cascades, interaction with the basic enzymes involved in tumor promotion and metastasis, interaction with oncogenes and oncoproteins, and, finally, direct or indirect interactions with nucleic acids and nucleoproteins. These actions involve almost the whole spectrum of basic cellular machinery – from the cell membrane to signaling cytoplasmic molecules and to the major nuclear components – and provide insights into their beneficial health effects (Kampa et al., 2007).

Polyphenols and Copper

Anti-cancer polyphenolic nutraceuticals from fruits, vegetables, and spices are generally recognized as anti-oxidants, but can be pro-oxidants in the presence of copper ions. Through multiple assays, Khan et al. (2013) show that polyphenols luteolin, apigenin, epigallocatechin-3-gallate, and resveratrol are able to inhibit cell proliferation and induce apoptosis in different cancer cell lines. Such cell death is prevented to a significant extent by cuprous chelator neocuproine and reactive oxygen species scavengers. We also show that normal breast epithelial cells, cultured in a medium supplemented with copper, become sensitized to polyphenol-induced growth inhibition.

Since the concentration of copper is significantly elevated in cancer cells, their results strengthen the idea that an important anti-cancer mechanism of plant polyphenols is mediated through intracellular copper mobilization and reactive oxygen species generation leading to cancer cell death. Moreover, this pro-oxidant chemo-preventive mechanism appears to be a mechanism common to several polyphenols with diverse chemical structures and explains the preferential cytotoxicity of these compounds toward cancer cells.

IGF-1; Prostate Cancer

The ability of polyphenols from tomatoes and soy (genistein, quercetin, kaempferol, biochanin A, daidzein and rutin) were examined for their ability to modulate insulin-like growth factor-I (IGF-I)–induced in vitro proliferation and apoptotic resistance in the AT6.3 rat prostate cancer cell line. IGF-I at 50 µg/L in serum-free medium produced maximum proliferation and minimized apoptosis. Genistein, quercetin, kaempferol and biochanin A exhibited dose-dependent inhibition of growth with a 50% inhibitory concentration (IC50) between 25 and 40 µmol/L, whereas rutin and daidzein were less potent with an IC50 of >60 µmol/L. Genistein and kaempferol potently induced G2/M cell-cycle arrest.

Genistein, quercetin, kaempferol and biochanin A, but not daidzein and rutin, counteracted the anti-apoptotic effects of IGF-I. Human prostate epithelial cells grown in growth factor-supplemented medium were also sensitive to growth inhibition by polyphenols. Genistein, biochanin A, quercetin and kaempferol reduced the insulin receptor substrate-1 (IRS-1) content of AT6.3 cells and prevented the down-regulation of IGF-I receptor β in response to IGF-I binding.

Several polyphenols suppressed phosphorylation of AKT and ERK1/2, and more potently inhibited IRS-1 tyrosyl phosphorylation after IGF-I exposure. In summary, polyphenols from soy and tomato products may counteract the ability of IGF-I to stimulate proliferation and prevent apoptosis via inhibition of multiple intracellular signaling pathways involving tyrosine kinase activity (Wang et al., 2003).

Flavonoids

Flavonoids have been linked to reducing the risk of major chronic diseases including cancer because they have powerful anti-oxidant activities in vitro, being able to scavenge a wide range of reactive species (e.g. hydroxyl radicals, peroxyl radicals, hypochlorous acid, and superoxide radicals) (Hollman & Katan, 2000).

Flavonoids are a group of more than 4,000 phenolic compounds that occur naturally in plants (Ren et al., 2003). These compounds commonly have the basic skeleton of phenylbenzopyrone structure (C6-C3-C6) consisting of 2 aromatic rings (A and B rings) linked by 3 carbons that are usually in an oxygenated central pyran ring, or C ring (12). According to the saturation level and opening of the central pyran ring, they are categorized mainly into flavones (basic structure, B ring binds to the 2 position), flavonols (having a hydroxyl group at the 3 position), flavanones (dihydroflavones) and flavanonols (dihydroflavonols; 2–3 bond is saturated), flavanols (flavan-3-ols and flavan-3,4-diols; C-ring is 1-pyran), anthocyanins (anthocyanidins; C-ring is 1-pyran, and 1–2 and 3–4 bonds are unsaturated), chalcones (C-ring is opened), isoflavonoids (mainly isoflavones; B ring binds to the 3 position), neoflavonoids (B ring binds to the 4-position), and biflavonoids (dimer of flavones, flavonols, and flavanones) (Iwashina, 2000; Cai et al., 2004; Cai et al., 2006; Ren et al., 2003)

Tannins

Tannins are natural, water-soluble, polyphenolic compounds with molecular weight ranging from 500 to 4,000, usually classified into 2 classes: hydrolysable tannins (gallo- and ellagi-tannins) and condensed tannins (proanthocyanidins) (Cai et al., 2004).

The former are complex polyphenols, which can be degraded into sugars and phenolic acids through either pH changes or enzymatic or nonenzymatic hydrolysis. The basic units of hydrolysable tannins of the polyster type are gallic acid and its derivatives (Fresco et al., 2006). Tannins are commonly found combined with alkaloids, polysaccharides, and proteins, particularly the latter (Han et al., 2007).

Stilbenes

Stilbenes are phenolic compounds displaying 2 aromatic rings linked by an ethane bridge, structurally characterized by the presence of a 1,2-diarylethene nucleus with hydroxyls substituted on the aromatic rings. They are distributed in higher plants and exist in the form of oligomers and in monomeric form (e.g. resveratrol, oxyresveratrol) and as dimeric, trimeric, and polymeric stilbenes or as glycosides.

The well-known compound, trans-resveratrol, a phytoalexin produced by plants, is the member of this chemical famil most abundant in the human diet (especially rich in the skin of red grapes), possessing a trihydroxystilben skeleton (Han et al., 2007). There are monomeric stilbenes in 4 species of medicinal herbs, that is, trans-resveratrol in root of Polygonum cuspidatum, Polygonum multiflorum, and P. lactiflora; piceatannol in root of P. multiflorum; and oxyresveratrol in fruit of Morus alba (Cai et al., 2006).

It was reported that dimeric stilbenes and stilbene glycosides were identified from these species (Xiao et al., 2002). In addition, 40 stilbene oligomers were isolated from 6 medicinal plant species (Shorea hemsleyana, Vatica rassak, Vatica indica, Hopea utilis, Gnetum parvifolium, and Kobresia nepalensis). Other stilbenes that have recently been identified in dietary sources, such as piceatannol and its glucoside (usually named astringin) and pterostilbene, are also considered as potential chemo-preventive agents. These and other in vitro and in vivo studies provide a rationale in support of the use of stilbenes as phytoestrogens to protect against hormone-dependent tumors (Athar et al., 2007).

Curcuminoids

Curcuminoids are ferulic acid derivatives, which contain 2 ferulic acid molecules linked by a methylene with a β -diketone structure in a highly conjugated system. Curcuminoids and ginerol analogues are natural phenolic compounds from plants of the family Zingiberaceae. Curcuminoids include 3 main chemical compounds: curcumin, demethoxycurcumin, and bisdemethoxycurcumin (Cai et al., 2006). All 3 curcuminoids impart the characteristic yellow color to turmeric, particularly to its rhizome, and are also major yellow pigments of mustard. Curcuminoids containing Curcuma longa (turmeric) and ginerol analogues containing Zingiber officinale (ginger) are not only used as Chinese traditional medicines but also as natural color agents or ordinary spices.

In addition, curcuminoids with anti-oxidant properties have been isolated from various Curcuma or Zingiber species, such as the Indian medicinal herb Curcuma xanthorrhiza.

Coumarins

Coumarins are lactones obtained by cyclization of cis-ortho-hydroxycinnamic acid, belonging to the phenolics with the basic skeleton of C6+ C3. This precursor is formed through isomerization and hydroxylation of the structural analogs trans-hydroxycinnamic acid and derivatives. Coumarins are present in plants in the free form and as glycosides. In general, coumarins are characterized by great chemical diversity, mainly differing in the degree of oxygenation of their benzopyrane moiety.

In nature, most coumarins are C7-hydroxylated (Fresco et al., 2006; Cai et al., 2006). Major coumarin constituents included simple hydroxylcoumarins (e.g. aesculin, esculetin, scopoletin, and escopoletin), furocoumarins and isofurocoumarin (e.g. psoralen and isopsoralen from Psoralea corylifolia), pyranocoumarins (e.g. xanthyletin, xanthoxyletin, seselin, khellactone, praeuptorin A), bicoumarins, dihydro-isocoumarins (e.g. bergenin), and others (e.g. wedelolactone from Eclipta prostrata) (Shan et al., 2005).

Plants, fruits, vegetables, olive oil, and beverages (coffee, wine, and tea) are all dietary sources of coumarins; for example, seselin from fruit of Seseli indicum, khellactone from fruit of Ammi visnaga, and praeuptorin A from Peucedanum praeruptorum (Sonnenberg et al., 1995). In previous studies, it was found that coumarins occurred in the medicinal herbs Umbelliferae, Asteraceae, Convolvulaceae, Leguminosae, Magnoliaceae, Oleaceae, Rutaceae, and Ranunculaceae, such as simple coumarins from A. annua, furocoumarins (5-methoxyfuranocoumarin) from Angelica sinensis, pyranocoumarins from Citrus aurantium, and isocoumarins from Agrimonia pilosa. Coumarins have also been detected in some Indian medicinal plants (e.g. Toddalia aculeata, Murraya exotica, Foeniculum vulgare, and Carum copticum) and dietary spices (e.g. cumin and caraway). In addition, coumestans, derivatives of coumarin, including coumestrol, a phytoestrogen, are found in a variety of medicinal and dietary plants such as soybeans and Pueraria mirifica (Chansakaow et al., 2000).

Lignans

Lignans are also derived from cis-o-hydroxycinnamic acid and are dimers (with 2 C6-C3 units) resulting from tail–tail linkage of 2 coniferl or sinapyl alcohol units (Cai et al., 2007). Lignans are mainly present in plants in the free form and as glycosides in a few (Fresco et al., 2006). Main lignan constituents are lignanolides (e.g. arctigenin, arctiin, secoisolariciresinol, and matairesinol from Arctium lappa), cyclolignanolides (e.g. chinensin from Polygala tenuifolia), bisepoxylignans (e.g. forsythigenol and forsythin from Forsythia suspensa), neolignans (e.g. magnolol from Cedrus deodara and Magnolia officinalis), and others (e.g. schizandrins, schizatherins, and wulignan from Schisandra chinensis; pinoresinol from Pulsatilla chinensis; and furofuran lignans from Cuscuta chinensis) (Surveswaran et al., 2007).

The famous tumor therapy drug podophyllotoxin (cyclolignanolide) was first identified in Podophyllum peltatum, which Native Americans used to treat warts, and also found in a traditional medicinal plant Podophyllum emodi var. chinense (Efferth et al., 2007). Two new lignans (podophyllotoxin glycosides) were isolated from the Chinese medicinal plant, Sinopodophyllum emodi (Zhao et al., 2002). Different lignans (e.g. cubebin, hinokinin, yatein, and isoyatein) were identified from leaves, berries, and stalks of Piper cubeba L. (Piperaceae), an Indonesian medicinal plant (Elfahmi et al., 2007).

Milder et al. (2005) established a lignan database from Dutch plant foods by quantifying lariciresinol, pinoresinol, secoisolariciresinol, and matairesinol in 83 solid foods and 26 beverages commonly consumed in The Netherlands. They reported that flaxseed (mainly secoisolariciresinol), sesame seeds, and Brassica vegetables (mainly pinoresinol and lariciresinol) contained unexpectedly high levels of lignans. Sesamol, sesamin, and their glucosides are also good examples of this type of compound, which comes from sesame oil and sunflower oil.

Quinones

Natural quinones in medicinal plants fall into 4 categories: anthraquinones, phenanthraquinones, naphthoquinones, and benzoquinones (Cai et al., 2004). Anthraquinones are the largest class of natural quinones and occur more widely in medicinal and dietary plants than other natural quinones (Cai et al., 2006). The hydroxyanthraquinones normally have 1 to 3 hydroxyl groups on the anthraquinone structure. Previous investigation found that quinones were distributed in 12 species of medicinal herbs from 9 families such as Polygalaceae, Rubiaceae, Boraginaceae, Labiatae, Leguminosae, Myrsinaceae, and so forth (Surveswaran et al., 2007).

For example, high content benzoquinones and derivatives (embelin, embelinol, embeliaribyl ester, embeliol) are found in Indian medicinal herb Embelia ribes; naphthoquinones (shikonin, alkannan, and acetylshikonin) come from Lithospermum erythrorhizon and juglone comes from Juglans regia; phenanthraquinones (tanshinone I, II A, and II B ) were detected in Salvia miltiorrhiza; denbinobin was detected in Dendrobium nobile; and many anthraquinones and their glycosides (e.g. rhein, emodin, chrysophanol, aloe-emodin, physcion, purpurin, pseudopurpurin, alizarin, munjistin, emodin-glucoside, emodin-malonyl-glucoside, etc.) were identified in the rhizomes and roots from P. cuspidatum (also in leaves), P. multiflorum, and R. officinale in the Polygalaceae and Rubia cordifolia in the Rubiaceae (Surveswaran et al., 2007; Huang et al., 2008). In addition, some naphthoquinones were isolated from maize (Zea mays L.) roots (Luthje et al., 1998).

References:

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Periplocin

Cancer: Lung, colorectal, leukemia

Action: Apoptosis-inducing, cytostatic effect

Apoptosis

The anti-tumor component of Cortex periplocae is periplocin. Periplocin is one of the cardenolides isolated from cortex periplocae which is used for treatment of rheumatoid arthritis and reinforcement of bones and tendons in traditional medicine.

Periplocin has been reported to inhibit many cell lines, including MCF-7, TE-13, QG-56, SMMC-7721, T24, Hela, K562, TE-13 and Eca-109 cells. Studies have shown that periplocin reduces the expression of survivin, an inhibitor of apoptosis. It also releases caspases-3 and -7 from complexes and thereby increases their activities, ultimately inducing tumor cell apoptosis (Zhao et al., 2009).

Lung Cancer

The anti-tumor activity of periplocin was investigated in lung cancer cells both in vitro and in vivo, and its anti-cancer mechanism was explored. Periplocin inhibited the growth of lung cancer cells and induced their apoptosis in a time- and dose-dependent manner by cell-cycle arrest in G0/G1 phase. Periplocin exhibited anti-tumor activity both in human (A549) and mouse (LL/2) lung cancer xenograft models. Immunohistochemical analysis revealed that intratumoral angiogenesis was significantly suppressed.

Furthermore, anti-cancer activity mediated by periplocin was associated with decreased level of phosphorylated AKT and ERK both in vitro and in vivo, which are important for cell growth and survival. Moreover, periplocin induced apoptosis by down-regulating Bcl-2 and up-regulating Bax, leading to activation of caspase-3 and caspase-9.

These findings suggest that periplocin could inhibit the growth of lung cancer both in vitro and in vivo, which could be attributed to the inhibition of proliferation and the induction of apoptosis signaling pathways, such as AKT and ERK. These observations provide further evidence on the anti-tumor effect of periplocin, and it may be of importance to further explore its potential role as a therapeutic agent for cancer (Lu et al., 2010).

Colorectal Carcinomas

The Wnt/beta-catenin signaling pathway plays an important role in the development and progression of human cancers, especially in colorectal carcinomas. Periplocin extracted from cortex periplocae (CPP) significantly inhibited the proliferation of SW480 cells in a time-and dose-dependent manner (P<0.01). CPP (0.5 microg/mL) also caused G0/G1 cell-cycle arrest of SW480 cells and induced cell apoptosis (P<0.05). Compared to untreated control cells, after the treatment with CPP, the protein levels of beta-catenin in total cell lysates, cytosolic extracts, and nuclear extracts were reduced (P<0.01); the binding activity of the TCF complex in nucleus to its specific DNA binding site was suppressed; mRNAs of the downstream target genes survivin, c-myc and cyclin D1 were decreased (P<0.01) while beta-catenin mRNA remained unchanged.

CPP could significantly inhibit the proliferation of SW480 cells, which may be through down-regulating the Wnt/beta-catenin signaling pathway (Du et al., 2009).

Pro-apoptotic and Cytostatic Effect/Leukemia

Cardenoliddes are steroid glycosides which are known to exert cardiotonic effects by inhibiting the Na(+)/K(+)-ATPase. Several of these compounds have been shown also to possess anti-tumor potential. The aim of the present work was the characterization of the tumor cell growth inhibition activity of four cardenolides, isolated from Periploca graeca L., and the mechanisms underlying such an effect.

The pro-apoptotic and cytostatic effect of the compounds was tested in U937 (monocytic leukemia) and PC3 (prostate adenocarcinoma). Characterization of apoptosis and cell-cycle impairment was obtained by cytofluorimetry and WB. Periplocymarin and periplocin were the most active compounds, periplocymarin being more effective than the reference compound ouabain. The reduction of cell number by these two cardenolides was due in PC3 cells mainly to the activation of caspase-dependent apoptotic pathways, while in U937 cells to the induction of cell-cycle impairment without extensive cell death. Interestingly, periplocymarin, at cytostatic but non-cytotoxic doses, was shown to sensitize U937 cells to TRAIL. Taken together, these data outline that cardiac glycosides are promising anti-cancer drugs and contribute to the identification of new natural cardiac glycosides to obtain chemically modified non-cardioactive/low toxic derivatives with enhanced anti-cancer potency (Bloise et al., 2009).

References

Bloise E, Braca A, De Tommasi N, Belisario MA. (2009). Pro-apoptotic and cytostatic activity of naturally occurring cardenolides. Cancer Chemother Pharmacol, 64(4):793-802. doi: 10.1007/s00280-009-0929-5.


Du YY, Liu X, Shan BE. (2009). Periplocin extracted from cortex periplocae induces apoptosis of SW480 cells through inhibiting the Wnt/beta-catenin signaling pathway. Ai Zheng, 28(5):456-60.


Lu ZJ, Zhou Y, Song Q, et al. (2010). Periplocin inhibits growth of lung cancer in vitro and in vivo by blocking AKT/ERK signaling pathways. Cell Physiol Biochem, 26(4-5):609-18. doi: 10.1159/000322328.


Zhao LM, Ai J, Zhang Q, et al. (2009). Periplocin (a sort of ethanol from Cortex periplocae) induces apoptosis of esophageal carcinoma cells by influencing expression of related genes. Tumor (Chin), 29:1025-1030.

Oxymatrine (Ku Shen)

Cancer:
Sarcoma, pancreatic, breast, liver, lung, oral, colorectal, stomach, gastric, adenoid cystic carcinoma

Action: Anti-angiogenesis, anti-inflammatory, anti-proliferative, chemo-sensitizer, chemotherapy support, cytostatic, radiation support, immunotolerance, induces apoptosis, decreases side-effects of Intensity Modulated Radiation Therapy (IMRT), Transcatheter Hepatic Arterial Chemoembolization (TACE)

Anti-cancer

Oxymatrine, isolated from the dried roots of Sophora flavescens (Aiton), has a long history of use in traditional Chinese medicine to treat inflammatory diseases and cancer. Kushen alkaloids (KS-As) and kushen flavonoids (KS-Fs) are well-characterized components in kushen. KS-As containing oxymatrine, matrine, and total alkaloids have been developed in China as anti-cancer drugs. More potent anti-tumor activities were identified in KS-Fs than in KS-As in vitro and in vivo (Sun et al., 2012).

Angiogenesis

Oxymatrine has been found to inhibit angiogenesis when administered by injection. The tumor-inhibitory rate and the vascular density were tested in animal tumor model with experimental treatment. The expression of VEGF and bFGF were measured by immunistological methods. When high doses were used, the tumor-inhibitory rate of oxymatrine was 31.36%, and the vascular density of S180 sarcoma was lower than that in the control group, and the expression of VEGF and bFGF was down-regulated. Oxymatrine hence has an inhibitory effect on S180 sarcoma and strong inhibitory effects on angiogenesis. Its mechanism may be associated with the down-regulating of VEGF and bFGF expression (Kong et al., 2003).

Immunotolerance

Matrine, a small molecule derived from the root of Sophora flavescens AIT, was demonstrated to be effective in inducing T cell anergy in human Jurkat cells. Induction of immunotolerance has become a new strategy for treating autoimmune conditions in recent decades. However, so far there is no ideal therapeutics available for clinical use. Medicinal herbs are a promising potential source of immunotolerance inducers. Bioactive compounds derived from medicinal plants were screened for inducing T cell anergy in comparison with the effect of well-known T cell anergy inducer, ionomycin.

The results showed that passage of the cells, and concentration and stimulation time of ionomycin on the cells, could influence the ability of T cell anergy induction. The cells exposed to matrine showed markedly decreased mRNA expression of interleukin-2, an indicator of T cell anergy, when the cells were stimulated by antigens, anti-OKT3 plus anti-CD28. Mechanistic study showed that ionomycin and matrine could up-regulate the anergy-associated gene expressions of CD98 and Jumonji and activate nuclear factor of activated T-cells (NFAT) nuclear translocation in absence of cooperation of AP-1 in Jurkat cells. Pre-incubation with matrine or ionomycin could also shorten extracellular signal-regulated kinase (ERK) and suppress c-Jun NH(2)-terminal kinase (JNK) expression on the anergic Jurkat cells when the cells were stimulated with anti-OKT-3 plus anti-CD28 antibodies. Thus, matrine is a strong candidate for further investigation as a T cell immunotolerance inducer (Li et al., 2010).

Induces Apoptosis

The cytotoxic effects of oxymatrine on MNNG/HOS cells were examined by MTT and bromodeoxyuridine (BrdU) incorporation assays. The percentage of apoptotic cells and the level of mitochondrial membrane potential ( Δψ m) were assayed by flow cytometry. The levels of apoptosis-related proteins were measured by Western blot analysis or enzyme assay Kit.

Results showed that treatment with oxymatrine resulted in a significant inhibition of cell proliferation and DNA synthesis in a dose-dependent manner, which has been attributed to apoptosis. Oxymatrine considerably inhibited the expression of Bcl-2 whilst increasing that of Bax.

Oxymatrine significantly suppressed tumor growth in female BALB/C nude mice bearing MNNG/HOS xenograft tumors. In addition, no evidence of drug-related toxicity was identified in the treated animals by comparing the body weight increase and mortality (Zhang et al., 2013).

Pancreatic Cancer

Cell viability assay showed that treatment of PANC-1 pancreatic cancer cells with oxymatrine resulted in cell growth inhibition in a dose- and time-dependent manner. Oxymatrine decreased the expression of angiogenesis-associated factors, including nuclear factor κB (NF-κB) and vascular endothelial growth factor (VEGF). Finally, the anti-proliferative and anti-angiogenic effects of oxymatrine on human pancreatic cancer were further confirmed in pancreatic cancer xenograft tumors in nude mice (Chen et al., 2013).

Induces Apoptosis in Pancreatic Cancer

Oxymatrine inhibited cell viability and induced apoptosis of PANC-1 cells in a time- and dose-dependent manner. This was accompanied by down-regulated expression of Livin and Survivin genes while the Bax/Bcl-2 ratio was up-regulated. Furthermore, oxymatrine treatment led to the release of cytochrome c and activation of caspase-3 proteins. Oxymatrine can induce apoptotic cell death of human pancreatic cancer, which might be attributed to the regulation of Bcl-2 and IAP families, release of mitochondrial cytochrome c, and activation of caspase-3 (Ling et al., 2011).

Decreases Side-effects of Intensity Modulated Radiation Therapy (IMRT)

The levels of sIL-2R and IL-8 in peripheral blood cells of patients with rectal cancer were measured after treatment with the compound matrine, in combination with radiation. Eighty-four patients diagnosed with rectal carcinoma were randomly divided into two groups: therapeutic group and control group.

The patients in the therapeutic group were treated with compound matrine and intensity- modulated radiation therapy (IMRT) (30 Gy/10 f/2 W), while the patients in control group were treated with IMRT. The clinical effects and the levels of IL-8 and sIL-2R tested by ELISA pre-radiation and post-radiation were compared. In addition, 42 healthy people were singled out from the physical examination center in the People's Hospital of Yichun city, which were considered as healthy controls.

The clinical effect and survival rate in the therapeutic group was significantly higher (47.6%) than those in the control group (21.4%). All patients were divided by improvement, stability, and progression of disease in accordance with Karnofsky Performance Scale (KPS). According to the KPS, 16 patients had improvement, 17 stabilized and 9 had disease progress, in the therapeutic group. However, the control group had 12 improvements, 14 stabilized, and 16 progress.

The quality of life in the therapeutic group was higher than tthat in the control group, by rank sum test. SIL-2R and IL-8 examination found that serum levels of sIL-2R and IL-8 were higher in rectal cancer patients before treatments than those in the healthy groups, by student test.

However, sIL-2R and IL-8 serum levels were found significantly lower in the 84 rectal cancer patients after radiotherapy. The level of sIL-2R and IL-8 in the therapeutic group was lower on the first and 14th day, post-radiation, when compared to the control group. However, there was no significant difference on the first day and 14th day, between both experimental groups post- therapy, according to the student test. Side-effects of hepatotoxicity (11.9%) and radiation proctitis (9.52%) were fewer in the therapeutic group.

Compound matrine can decrease the side-effects of IMRT, significantly inhibit sIL-2R and IL-8 in peripheral blood from radiation, and can improve survival quality in patients with rectal cancer (Yin et al., 2013).

Gastric Cancer

The clinical effect of matrine injection, combined with S-1 and cisplatin (SP), in the treatment of advanced gastric cancer was investigated. Seventy-six cases of advanced gastric cancer were randomly divided into either an experimental group or control group. Patients in the two groups were treated with matrine injection combined with SP regimen, or SP regimen alone, respectively.

The effectiveness rate of the experimental group and control group was 57.5% and 52.8% respectively. Therapeutic effect of the two groups of patients did not differ significantly. Occurrence rate of symptom indexes in the treatment group were lower than those of control group, with exception of nausea and vomiting, in which there was no significant difference.

The treatment of advanced gastric cancer with matrine injection, combined with the SP regimen, can significantly improve levels of white blood cells and hemoglobin, liver function, incidence of diarrhea and constipation, and neurotoxicity, to improve the quality of life in patients with advanced gastric cancer (Xia, 2013).

Adenoid Cystic Carcinoma

The effects of compound radix Sophorae flavescentis injection on proliferation, apoptosis and Caspase-3 expression in human adenoid cystic carcinoma ACC-2 cells was investigated.

Compound radix Sophorae flavescentis injection could inhibit the proliferation of ACC-2 cells in vitro, and the dosage effect relationship was significant (P < 0.01). IC50 of ACC-2 was 0.84 g/ml. Flow cytometry indicated that radix Sophorae flavescentis injection could arrest ACC-2 cells at the G0/G1 phase, with a gradual decrease of presence in the G2/M period and S phase. With an increase in dosage, ACC-2 cell apoptosis rate increased significantly (P < 0.05 or P < 0.01).

Radix Sophorae flavescentis injection could enhance ACC-2 cells Caspase-3 protein expression (P < 0.05 or P < 0.01), in a dose-dependent manner. It also could effectively restrain human adenoid cystic carcinoma ACC-2 cells Caspases-3 protein expression, and induce apoptosis, inhibiting tumor cell proliferation (Shi & Hu, 2012).

Breast Cancer Post-operative Chemotherapy

A retrospective analysis of oncological data of 70 post-operative patients with breast cancer from January 2008 to August 2011 was performed. According to the treatment method, the patients were divided into a therapy group (n=35) or control group (n=35). Patients in the control group were treated with the taxotere, adriamycin and cyclophosphamide regimen (TAC). The therapy group was treated with a combination of TAC and sophora root injection. Improved quality of life and incidence of adverse events, before and after treatment, for 2 cycles (21 days to a cycle) were compared.

The objective remission rate of therapy group compared with that of control group was not statistically significant (P > 0.05), while the difference of the disease control rate in two groups was statistically significant (P < 0.05). The improvement rate of total quality of life in the therapy group was higher than that of the control group (P < 0.05). The drop of white blood cells and platelets, gastrointestinal reaction, elevated SGPT, and the incidence of hair loss in the therapy group were lower than those of the control group (P < 0.05).

Sophora root injection combined with chemotherapy in treatment of breast cancer can enhance the effect of chemotherapy, reduce toxicity and side-effects, and improve quality of life (An, An & Wu, 2012).

Lung Cancer Pleural Effusions

The therapeutic efficiency of fufangkushen injection, IL-2, α-IFN on lung cancer accompanied with malignancy pleural effusions, was observed.

One hundred and fifty patients with lung cancer, accompanied with pleural effusions, were randomly divided into treatment and control groups. The treatment group was divided into three groups: injected fufangkushen plus IL-2, fufangkushen plus α-tFN, and IL-2 plus α-IFN, respectively. The control group was divided into three groups and injected fufangkushen, IL-2 and α-IFN, respectively. Therapeutic efficiency and adverse reactions were observed after four weeks.

The effective rate of fufangkushen, IL-2, and α-IFN in a combination was significantly superior to single pharmacotherapy. The effective rate of fufangkushen plus ct-IFN was highest. In adverse reactions, the incidence of fever, chest pains, and the reaction of gastrointestinal tract in the treatment group were significantly less than in the matched group.

The effect of fufangkushen, IL-2, and α-IFN, in a combination, on lung cancer with pleural effusions was significantly better than single pharmacotherapy. Moreover, the effect of fufangknshen plus IL-2 or α-IFN had the greatest effect (Hu & Mei, 2012).

Colorectal Cancer Immunologic Function

The effects of compound Kushen (Radix sophorae flavescentis) injection on the immunologic function of patients after colorectal cancer resection, were studied.

Eighty patients after colorectal cancer resection were randomly divided into two groups: 40 patients in the control group were treated with routine chemotherapy including 5-fluorouridine(5-FU), calcium folinate(CF) and oxaliplatin, and 40 patients in the experimental group were treated with the same chemotherapy regime combined with 20 mL·d-1 compound Kushen injection, for 10 days during chemotherapy.

In the control group the numbers of CD3+,CD4+T cells, NK cells and CD4+/CD8+ ratio significantly declined relative to prior to chemotherapy (P < 0.05), while CD8+T lymphocyte number increased significantly. In the experimental group, there were no significant differences between the numbers of CD3+,CD4+,CD8+T cells, NK cells, and CD4+/CD8+ ratio, before and after chemotherapy (P > 0.05).

After chemotherapy, the numbers of CD3+,CD4+T cells, NK cells and CD4+/CD8+ ratio were higher in the experimental group than in the control group (P0.05), while the number of CD8+T lymphocyte was similar between two groups. Compound Kushen injection can improve the immunologic function of patients receiving chemotherapy after colorectal cancer resection (Chen, Yu, Yuan, & Yuan, 2009).

Stage III and IV non-small-cell lung cancer (NSCLC)

A total of 286 patients with advanced NSCLC were enrolled for study. The patients were treated with either compound Kushen injection in combination with NP (NVB + CBP) chemotherapy (vinorelbine and carboplatin, n = 144), or with NP (NVB + CBP) chemotherapy alone (n = 142). The chemotherapy was performed for 4 cycles of 3 weeks, and the therapeutic efficacy was evaluated every 2 weeks. The following indicators were observed: levels of Hb, WBC, PLT and T cell subpopulations in blood, serum IgG level, short-term efficacy, adverse effects and quality of life.

The gastrointestinal reactions and the myelosuppression in the combination chemotherapy group were alleviated when compared with the chemotherapy alone group, showing a significant difference. (P < 0.05). CD (8)(+) cells were markedly declined in the combination chemotherapy group, and the CD (4)(+)/CD (8)(+) ratio showed an elevation trend in the chemotherapy alone group.

The Karnofsky Performance Scale (KPS) scores and serum IgM and IgG levels were higher in the combination chemotherapy group than those in the chemotherapy alone group (P < 0.01 and P < 0.05). The serum lgA levels were not significantly different in the two groups.

The compound Kushen injection plus NP chemotherapy regimen showed better therapeutic effect, reduced adverse effects of chemotherapy and improved the quality of life in patients with stage III and IV NSCLC (Fan et al., 2010).

Lung Adenocarcinoma

Suppression effects of different concentrations of matrine injection and matrine injection combined with anti-tumor drugs on lung cancer cells were measured by methyl thiazolyl tetrazolium (MTT) colorimetric assay.

Different concentrations of matrine injection could inhibit the growth of SPCA/I human lung adenocarcinoma cells. There was a positive correlation between the inhibition rate and the drug concentration. Different concentrations of matrine injection combined with anti-tumor drugs had a higher growth inhibition rate than anti-tumor drugs alone.

Matrine injection has direct growth suppression effect on SPCA/I human lung adenocarcinoma cells and SS+ injection combined with anti-tumor drugs shows a significant synergistic effect on tumor cells (Zhu, Jiang, Lu, Guo, & Gan, 2008).

Transcatheter Hepatic Arterial Chemoembolization (TACE)

The effect of composite Kushen injection combined with transcatheter hepatic arterial chemoembolization (TACE) on unresectable primary liver cancer, was studied.

Fifty-seven patients with unresectable primary liver cancer were randomly divided into two groups. The treatment group with 27 cases was treated by TACE combined with composite Kushen injection, and the control group with 30 cases was treated by TACE alone. The clinical curative effects were observed after treatment in both groups.

One-, 2-, and 3-year survival rates of the treatment group were 67%, 48%, and 37% respectively, and those of control group were 53%, 37%, and 20% respectively. There were significant differences between both groups (P < 0.05).

Combined TACE with composite Kushen injection can increase the efficacy of patients with unresectable primary liver cancer (Wang & Cheng, 2009).

References

An AJ, An GW, Wu YC. (2012). Observation of compound recipe light yellow Sophora root injection combined with chemotherapy in treatment of 35 postoperative patients with breast cancer. Medical & Pharmaceutical Journal of Chinese People's Liberation Army, 24(10), 43-46. doi: 10.3969/j.issn.2095-140X.2012.10.016.


Chen G, Yu B, Yuan SJ, Yuan Q. (2009). Effects of compound Kushen injection on the immunologic function of patients after colorectal cancer resection. Evaluation and Analysis of Drug-Use in Hospitals of China, 2009(9), R735.3. doi: cnki:sun:yypf.0.2009-09-025.


Chen H, Zhang J, Luo J, et al. (2013) Anti-angiogenic effects of oxymatrine on pancreatic cancer by inhibition of the NF- κ B-mediated VEGF signaling pathway. Oncol Rep, 30(2):589-95. doi: 10.3892/or.2013.2529.


Fan CX, Lin CL, Liang L, et al. (2010). Enhancing effect of compound Kushen injection in combination with chemotherapy for patients with advanced non-small-cell lung cancer. Chinese Journal of Oncology, 32(4), 294-297.


Hu DJ, Mei, XD. (2012). Observing therapeutic efficiency of fufangkushen injection, IL-2, α -IFN on lung cancer accompanied with malignancy pleural effusions. Journal of Clinical Pulmonology, 17(10), 1844-1845.


Kong QZ, Huang DS, Huang T, et al. (2003). Experimental study on inhibiting angiogenesis in mice S180 by injections of three traditional Chinese herbs. Chinese Journal of Hospital Pharmacy, 2003-11. doi: CNKI:SUN:ZGYZ.0.2003-11-002


Li T, Wong VK, Yi XQ, et al. (2010). Matrine induces cell anergy in human Jurkat T cells through modulation of mitogen-activated protein kinases and nuclear factor of activated T-cells signaling with concomitant up-regulation of anergy-associated genes expression. Biol Pharm Bull, 33(1):40-6.


Ling Q, Xu X, Wei X, et al. (2011). Oxymatrine induces human pancreatic cancer PANC-1 cells apoptosis via regulating expression of Bcl-2 and IAP families, and releasing of cytochrome c. J Exp Clin Cancer Res, 30:66. doi: 10.1186/1756-9966-30-66.


Shi B, Xu H. (2012). Effects of compound radix Sophorae flavescentis injection on proliferation, apoptosis and caspase-3 expression in adenoid cystic carcinoma ACC-2 cells. Chinese Pharmacological Bulletin, 5(10), 721-724.


Sun M, Cao H, Sun L, et al. (2012). Anti-tumor activities of kushen: literature review. Evid Based Complement Alternat Med, 2012;2012:373219. doi: 10.1155/2012/373219.


Wang HM, Cheng XM. (2009). Composite Ku Shen injection combined with hepatic artery embolism on unresectable primary liver cancer. Modern Journal of Integrated Traditional Chinese and Western Medicine, 18(2), 1334–1335.


Xia G. (2013). Clinical observation of compound matrine injection combined with SP regimen in advanced gastric cancer. Journal of Liaoning Medical University, 2013(1), 37-38.


Yin WH, Sheng JW, Xia HM, et al. (2013). Study on the effect of compound matrine on the level of sIL-2R and IL-8 in peripheral blood cells of patients with rectal cancer to radiation. Global Traditional Chinese Medicine, 2013(2), 100-104.


Zhang Y, Sun S, Chen J, et al. (2013). Oxymatrine induces mitochondria dependent apoptosis in human osteosarcoma MNNG/HOS cells through inhibition of PI3K/Akt pathway. Tumor Biol.


Zhu MY, Jiang ZH, Lu YW, Guo Y, Gan JJ. (2008). Matrine and anti-tumor drugs in inhibiting the growth of human lung cancer cell line. Journal of Chinese Integrative Medicine, 6(2), 163-165. doi: 10.3736/jcim20080211.

Nomilin

Cancer: Melanoma, breast cancer

Action: Anti-angiogenic

Nomilin is a triterpenoid present in common edible citrus fruits (Citrus grandis [(L.) Osb.], Citrus unshiu [(Swingle) Marcow.] and Citrus reticulata (Blanco)) with putative anti-cancer properties.

Melanoma

Nomilin possess anti-metastatic action, inducing metastasis in C57BL/6 mice through the lateral tail vein using highly metastatic B16F-10 melanoma cells. Administration of nomilin inhibited tumor nodule formation in the lungs (68%) and markedly increased the survival rate of the metastatic tumor–bearing animals. Nomilin showed an inhibition of tumor cell invasion and activation of matrix metalloproteinases. Treatment with nomilin induced apoptotic response.

Nomilin treatment also exhibited a down-regulated Bcl-2 and cyclin-D1 expression and up-regulated p53, Bax, caspase-9, caspase-3, p21, and p27 gene expression in B16F-10 cells. Pro-inflammatory cytokine production and gene expression were found to be down-regulated in nomilin-treated cells. The study also reveals that nomilin could inhibit the activation and nuclear translocation of anti-apoptotic transcription factors such as nuclear factor (NF)-κB, CREB, and ATF-2 in B16F-10 cells (Pratheeshkumar et al., 2011).

Breast Cancer; ER+

A panel of 9 purified limonoids, including limonin, nomilin, obacunone, limonexic acid (LNA), isolimonexic acid (ILNA), nomilinic acid glucoside (NAG), deacetyl nomilinic acid glucoside (DNAG), limonin glucoside (LG) and obacunone glucoside (OG) as well as 4 modified compounds such as limonin methoxime (LM), limonin oxime (LO), defuran limonin (DL), and defuran nomilin (DN), were screened for their cytotoxicity on estrogen receptor (ER)-positive (MCF-7) or ER-negative (MDA-MB-231) human breast cancer cells. Findings indicated that the citrus limonoids may have potential for the prevention of estrogen-responsive breast cancer (MCF-7) via caspase-7 dependent pathways (Lin et al., 2013).

Blocks Angoigenesis

Nomilin significantly inhibited tumor-directed capillary formation. Serum pro-inflammatory cytokines such as IL-1β, IL-6, TNF-α and GM-CSF and also serum NO levels were significantly reduced by the treatment of nomilin. Administration of nomilin significantly reduced the serum level of VEGF, a pro-angiogenic factor and increased the anti-angiogenic factors IL-2 and TIMP-1. Nomilin significantly retarded endothelial cell proliferation, migration, invasion and tube formation. These data clearly demonstrate the anti-angiogenic potential of nomilin by down-regulating the activation of MMPs, production of VEGF, NO and pro-inflammatory cytokines as well as up-regulating IL-2 and TIMP (Pratheeshkumar et al., 2011).

References

Kim J, Jayaprakasha GK, Patil BS. (2013). Limonoids and their anti-proliferative and anti-aromatase properties in human breast cancer cells. Food Funct, 4(2):258-65. doi: 10.1039/c2fo30209h.


Pratheeshkumar P, Raphael TJ & Kuttan G. (2011). Nomilin Inhibits Metastasis via Induction of Apoptosis and Regulates the Activation of Transcription Factors and the Cytokine Profile in B16F-10 Cells. Integr Cancer Ther. doi: 10.1177/1534735411403307


Pratheeshkumar P, Kuttan G. (2011). Nomilin inhibits tumor-specific angiogenesis by down-regulating VEGF, NO and pro-inflammatory cytokine profile and also by inhibiting the activation of MMP-2 and MMP-9. Eur J Pharmacol, 668(3):450-8. doi: 10.1016/j.ejphar.2011.07.029.

Naringin

Cancer: TNBCa, melanoma, breast, colon, cervical

Action: Anti-inflammatory, anti-carcinogenic

Citrus plants are known to possess beneficial biological activities for human health. The total phenolics and flavonoids from a methanolic extract contained high total phenolics and flavonoids compared to ethanolic and boiling water extracts of Citrus aurantium. The anti-inflammatory result of methanolic extract showed appreciable reduction in nitric oxide production of stimulated RAW 264.7 cells at the presence of plant extract.

Breast Cancer, Colon Cancer

The anti-cancer activity of the methanolic extract of Citrus aurantium was investigated in vitro against human cancer cell lines; breast cancer MCF-7; MDA-MB-231 cell lines, human colon adenocarcinoma HT-29 cell line and Chang cell as a normal human hepatocyte. The obtained result demonstrated the moderate to appreciable activities against all cell lines tested and the compounds present in the extracts are non-toxic which make them suitable as potential therapeutics (Karimi et al., 2012).

Triple Negative (ER-/PR-/HER2-)

Breast Cancer (TNBCa)

Camargo et al. (2012) demonstrated that naringin inhibited cell proliferation, and promoted cell apoptosis and G1 cycle arrest, accompanied by increased p21 and decreased survivin. Meanwhile, β-catenin signaling pathway was found to be suppressed by naringin.

Levels of the pro-inflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) are raised in patients with TNBCa. Inhibition of tumor growth, survival increase and the reduction of TNF-α and IL-6 levels in rats bearing W256 treated with naringin strongly suggest that this compound has potential as an anti-carcinogenic drug.

Results indicate that naringin could inhibit growth potential of Triple-negative (ER-/PR-/HER2-) breast cancer (TNBC) by modulating -catenin pathway, which suggests naringin might be used as a potential supplement for the prevention and treatment of breast cancer (Li et al., 2013).

Cervical Cancer

Fruit-based cancer prevention entities, such as flavonoids and their derivatives, have demonstrated a marked ability to inhibit preclinical models of epithelial cancer cell growth and tumor formation. Ramesh & Alshatwi (2013) looked at the role of naringin-mediated chemo-prevention in relation to cervical carcinogenesis. The results suggest that the induction of apoptosis by naringin is through both death-receptor and mitochondrial pathways. Taken together, our results suggest that naringin might be an effective agent to treat human cervical cancer.

Melanoma

A study by Huang, Yang, Chiou (2011) investigated the molecular events of melanogenesis induced by naringenin in murine B16-F10 melanoma cells. Melanin content, tyrosinase activity and Western blot analysis were performed to elucidate the possible underlying mechanisms. Exposure of melanoma cells to naringenin resulted in morphological changes accompanied by the induction of melanocyte differentiation-related markers, such as melanin synthesis, tyrosinase activity, and the expression of tyrosinase and microphthalmia-associated transcription factor (MITF). They concluded that naringenin induced melanogenesis through the Wnt-β-catenin-signaling pathway.

References

Camargo CA, Gomes-Marcondes MC, Wutzki NC, Aoyama H. (2013). Naringin inhibits tumor growth and reduces interleukin-6 and tumor necrosis factor α levels in rats with Walker 256 carcinosarcoma. Anti-cancer Res, 32(1):129-33.


Huang YC, Yang CH, Chiou YL. (2011). Citrus flavanone naringenin enhances melanogenesis through the activation of Wnt/ β -catenin signaling in mouse melanoma cells. Phytomedicine. 18(14):1244-9. doi: 10.1016/j.phymed.2011.06.028.


Karimi E, Oskoueian E, Hendra R, Oskoueian A, Jaafar HZ. (2012). Phenolic compounds characterization and biological activities of Citrus aurantium bloom. Molecules, 17(2):1203-18. doi: 10.3390/molecules17021203.


Li HZ, Yang B, Huang J, et al. (2013). Naringin inhibits growth potential of human triple-negative breast cancer cells by targeting -catenin signaling pathway. Toxicology Letters, 220(2013):219-228


Ramesh E, Alshatwi AA. (2013). Naringin induces death receptor and mitochondria-mediated apoptosis in human cervical cancer (SiHa) cells. Food Chem Toxicol. 51:97-105. doi: 10.1016/j.fct.2012.07.033.

Moscatilin

Cancers:
Colon, lung, placenta, stomach, breast metastasis

Action: Anti-angiogenic, anti-metastatic, anti-tubulin, cytostatic, cytotoxic, cell-cycle arrest, anti-inflammatory

Stomach Cancer, Lung Cancer, Placental

The efficacy of using moscatilin, a natural anti-platelet agent extracted from the stems of Dendrobrium loddigesii, as an anti-cancer agent was studied. Results demonstrated that moscatilin exerts potent cytotoxic effect against cancer cell lines derived from different tissue origins, including those from the placenta, stomach, and lung, but not those from the liver. In addition, the mechanism of action of moscatilin may be related to its ability to induce a G2 phase arrest in responsive cells.

However, unlike some G2 arresting agents, moscatilin has no detectable inhibitory effect on cyclin B–cdc-2 kinase activity. Thus, the precise nature of its cytotoxic mechanism remains to be determined.

Results suggest that moscatilin is potentially efficacious for chemo-prevention and/or chemotherapy against some types of cancer (Ho & Chen, 2003).

Colorectal Cancer

The growth inhibition of moscatilin was screened on several human cancer cell lines. The effect of moscatilin on tubulin was detected in vitro. Following moscatilin treatment on colorectal HCT-116 cells, c-Jun NH(2)-terminal protein kinase (JNK) and caspase activation was studied by Western blot analysis, and DNA damage was done by Comet assay. Moscatilin induced a time-dependent arrest of the cell-cycle at G2/M, with an increase of cells at sub-G1. Moscatilin inhibited tubulin polymerization, suggesting that it might bind to tubulins. A parallel experiment showed that SP600125 significantly inhibits Taxol and vincristine induced HCT-116 cell apoptosis. This suggests that the JNK activation may be a common mechanism for tubulin-binding agents.

Collectively, results suggest that moscatilin induces apoptosis of colorectal HCT-116 cells via tubulin depolymerization and DNA damage leading to the activation of JNK and mitochondria-involved intrinsic apoptosis pathway (Chen et al., 2008).

Anti-inflammatory

Results showed that moscatilin (10-100 microM) had a significant inhibition in a concentration-dependent manner on pro-inflammatory enzymes (COX-2 and iNOS) expression and macrophage activation under LPS (100 ng/mL) treatment.

Hypoxia-inducible factor 1 (HIF-1) alpha was reported to initiate inflammation under cytokine stimulation or hypoxic conditions. Moscatilin had significant inhibition on HIF-1 expression via down-regulation of HIF-1 mRNA without affecting cell viability, translation machinery, or proteasome-mediated degradation of HIF-1. Collective data demonstrarted that moscatilin inhibited both COX-2 and iNOS expressions after LPS treatment in RAW264.7. Furthermore, moscatilin's inhibitory effect appears to be dependent on the repression of HIF-1alpha accumulation and NF-kappaB activation (Liu et al., 2010).

Lung Cancer; Angiogenesis

Moscatilin significantly inhibited growth of lung cancer cell line A549 (NSCLC) and suppressed growth factor-induced neovascularization. In addition, VEGF- and bFGF-induced cell proliferation, migration, and tube formation of HUVECs was markedly inhibited by moscatilin. Western blotting analysis of cell signaling molecules indicated that moscatilin inhibited ERK1/2, Akt, and eNOS signaling pathways in HUVECs.

Results suggest that inhibition of angiogenesis by moscatilin may be a major mechanism in cancer therapy (Tsai et al., 2010).

Lung Cancer

Investigation demonstrated that non-toxic concentrations of moscatilin were able to inhibit human non-small-cell lung cancer H23 cell migration and invasion. The inhibitory effect of moscatilin was associated with an attenuation of endogenous reactive oxygen species (ROS), in which hydroxyl radical was identified as a dominant species in the suppression of filopodia formation.

Results indicate a novel molecular basis of moscalitin inhibiting lung cancer cell motility and invasion. Moscalitin may have promising anti-metastatic potential as an agent for lung cancer therapy (Kowitdamrong, Chanvorachote, Sritularak & Pongrakhananon, 2013).

Breast Cancer; Metastasis

Moscatilin, derived from the orchid Dendrobrium loddigesii, has shown anti-cancer activity. The mechanism by which moscatilin suppresses the migration and metastasis of human breast cancer MDA-MB-231 cells in vitro and in vivo was evaluated.

Moscatilin was found to significantly inhibit breast cancer MDA-MB-231 cell migration by using scratch assays and Boyden chambers.

In an MDA-MB-231 metastatic animal model, moscatilin (100 mg/kg) significantly suppressed breast cancer metastasis to the lungs and reduced the number of metastatic lung nodules and lung weight without causing any toxicity.

Results indicated that moscatilin inhibited MDA-MB-231 cell migration via Akt- and Twist-dependent pathways, consistent with moscatilin's anti-metastatic activity in vivo. Therefore, moscatilin may be an effective compound for the prevention of human breast cancer metastasis (Pai et al., 2013).

References

Chen TH, Pan SL, Guh JH, et al. (2008). Moscatilin induces apoptosis in human colorectal cancer cells: a crucial role of c-Jun NH2-terminal protein kinase activation caused by tubulin depolymerization and DNA damage. Clinical Cancer Research, 14(13), 4250-4258. doi: 10.1158/1078-0432.CCR-07-4578.


Ho CK, Chen CC. (2003). Moscatilin from the orchid Dendrobrium loddigesii is a potential anti-cancer agent. Cancer Investigation, 21(5), 729-736.


Kowitdamrong A, Chanvorachote P, Sritularak B, Pongrakhananon V. (2013). Moscatilin inhibits lung cancer cell motility and invasion via suppression of endogenous reactive oxygen species. BioMed Research International., 2013, 765894. doi: 10.1155/2013/765894.


Liu YN, Pan SL, Peng CY, et al. (2010). Moscatilin repressed lipopolysaccharide-induced HIF-1alpha accumulation and NF-kappaB activation in murine RAW264.7 cells. Shock, 33(1), 70-5. doi: 10.1097/SHK.0b013e3181a7ff4a.


Pai HC, Chang LH, Peng CY, et al. (2013). Moscatilin inhibits migration and metastasis of human breast cancer MDA-MB-231 cells through inhibition of Akt and Twist signaling pathway.

Journal of Molecular Medicine (Berlin), 91(3), 347-56. doi: 10.1007/s00109-012-0945-5.

Tsai AC, Pan SL, Liao CH, et al. (2010). Moscatilin, a bibenzyl derivative from the India orchid Dendrobrium loddigesii, suppresses tumor angiogenesis and growth in vitro and in vivo. Cancer Letters, 292(2), 163-70. doi: 10.1016/j.canlet.2009.11.020.

Matricaria chamomilla/Matricaria recutita

Cancer: Colorectal., ovarian, testicular, bladder, lung

Action: Neuropathy, anti-inflammatory

Colorectal Cancer; Ovarian Cancer; Testicular Cancer; Bladder Cancer; Lung Cancer; Chemotherapy

Studies have shown that cisplatin could have painful effects on human and animal models. Matricaria chamomilla (MC) has analgesic and anti-inflammatory effects, and may hence be an effective treatment for ciplatin-induced peripheral neuropathy as a replacement for morphine. Experiments were performed on 60 NMRI male mice weighed 25 g to 30 g, which have been divided into 6 groups. The first group received normal saline; the second group received MC hydroalcoholic extract; the third group received cisplatin; the fourth group received MC hydroalcoholic extract and cisplatin, 96 hours before formalin test; the fifth group received morphine and the sixth group received cisplatin and morphine.

Results showed that formalin induced significant (P < 0.05) pain response (the first phase: 0–5 min and the second phase: 15–40 min after injection). Administration of MC extract before formalin injection showed significant (P < 0.05) decrease of pain responses in the first and second phase. Administration of cisplatin produced significant (P < 0.05) increase in pain response in both phases of formalin test. Injection of MC extract and cisplatin together have shown that MC is able to decrease the second phase of cisplatin-induced pain significantly (P < 0.05).

In comparison morphine has analgesic effects in the first phase and MC extract has anti- inflammatory effects in the second phase of formalin test significantly (P < 0.05). MC and cisplatin have analgesic and painful neuropathic respective effects, and MC hydroalcoholic extract is able to decrease cisplatin-induced pain and inflammation better than morphine (Abad et al., 2011).

Anti-inflammatory

Flavonoid-7-glycosides, major constituents of chamomile flowers, may be responsible for the anti-inflammatory action, which is due to the inhibition of neutrophil elastase and gastric metalloproteinase-9 activity and secretion; the inhibition occurring in a concentration dependent manner (Bulgari et al., 2012).

The anti-cancer properties of aqueous and methanolic extracts of Matricaria chamomilla against various human cancer cell lines were investigated. Chamomile exposure resulted in differential apoptosis in cancer cells but not in normal cells at similar doses. HPLC analysis of chamomile extract confirmed apigenin 7-O-glucoside as the major constituent of chamomile; some minor glycoside components were also observed. Apigenin glucosides inhibited cancer cell growth but to a lesser extent than the parent aglycone, apigenin (Srivastava & Gupta, 2007).

References

Abad NA, Nouri MHK, Gharjanie A, Tavakoli F. (2011). Effect of Matricaria chamomilla Hydroalcoholic Extract on Cisplatin-induced Neuropathy in Mice. Chinese Journal of Natural Medicines, 9(2):126–131


Bulgari M, Sangiovanni E, Colombo E, et al. (2012). Inhibition of neutrophil elastase and metalloprotease-9 of human adenocarcinoma gastric cells by chamomile (Matricaria recutita L.) infusion. Phytother Res, 26(12):1817-22. doi: 10.1002/ptr.4657.


Srivastava JK, Gupta S. (2007). Anti-proliferative and apoptotic effects of chamomile extract in various human cancer cells. J Agric Food Chem, 55(23):9470-8.

Magnolol

Cancer:
Bladder, breast, colon, prostate, glioblastoma, ovarian, leukemia, lung

Action: Anti-inflammatory, apoptosis, inhibits angiogenesis, anti-metastatic

Magnolol (Mag), an active constituent isolated from the Chinese herb hou po (Magnolia officinalis (Rehder & Wilson)) has long been used to suppress inflammatory processes. It has anti-cancer activity in colon, hepatoma, and leukemia cell lines.

Anti-inflammatory

Magnolol (Mag) suppressed IL-6-induced promoter activity of cyclin D1 and monocyte chemotactic protein (MCP)-1 for which STAT3 activation plays a role. Pre-treatment of ECs with Mag dose-dependently inhibited IL-6-induced Tyr705 and Ser727 phosphorylation in STAT3 without affecting the phosphorylation of JAK1, JAK2, and ERK1/2. Mag pre-treatment of these ECs dose-dependently suppressed IL-6-induced promoter activity of intracellular cell adhesion molecule (ICAM)-1 that contains functional IL-6 response elements (IREs).

In conclusion, our results indicate that Mag inhibits IL-6-induced STAT3 activation and subsequently results in the suppression of downstream target gene expression in ECs. These results provide a therapeutic basis for the development of Mag as an anti-inflammatory agent for vascular disorders including atherosclerosis (Chen et al., 2006).

Bladder Cancer; Inhibits Angiogenesis

In the present study, Chen et al. (2013) demonstrated that magnolol significantly inhibited angiogenesis in vitro and in vivo, evidenced by the attenuation of hypoxia and vascular endothelial growth factor (VEGF)-induced tube formation of human umbilical vascular endothelial cells, vasculature generation in chicken chorioallantoic membrane, and Matrigel plug.

In hypoxic human bladder cancer cells (T24), treatment with magnolol inhibited hypoxia-stimulated H2O2 formation, HIF-1α induction including mRNA, protein expression, and transcriptional activity as well as VEGF secretion. Interestingly, magnolol also acts as a VEGFR2 antagonist, and subsequently attenuates the downstream AKT/mTOR/p70S6K/4E-BP-1 kinase activation both in hypoxic T24 cells and tumor tissues. As expected, administration of magnolol greatly attenuated tumor growth, angiogenesis and the protein expression of HIF-1α, VEGF, CD31, a marker of endothelial cells, and carbonic anhydrase IX, an endogenous marker for hypoxia, in the T24 xenograft mouse model.

Collectively, these findings strongly indicate that the anti-angiogenic activity of magnolol is, at least in part, mediated by suppressing HIF-1α/VEGF-dependent pathways, and suggest that magnolol may be a potential drug for human bladder cancer therapy.

Colon Cancer; Induces Apoptosis

Emerging evidence has suggested that activation of AMP-activated protein kinase (AMPK), a potential cancer therapeutic target, is involved in apoptosis in colon cancer cells. However, the effects of magnolol on human colon cancer through activation of AMPK remain unexplored.

Magnolol displayed several apoptotic features, including propidium iodide labeling, DNA fragmentation, and caspase-3 and poly(ADP-ribose) polymerase cleavages. Park et al. (2012) showed that magnolol induced the phosphorylation of AMPK in dose- and time-dependent manners.

Magnolol down-regulated expression of the anti-apoptotic protein Bcl2, up-regulated expression of pro-apoptotic protein p53 and Bax, and caused the release of mitochondrial cytochrome c. Magnolol-induced p53 and Bcl2 expression was abolished in the presence of compound C. Magnolol inhibited migration and invasion of HCT-116 cells through AMPK activation. These findings demonstrate that AMPK mediates the anti-cancer effects of magnolol through apoptosis in HCT-116 cells.

Ovarian Cancer

Treatment of HER-2 overexpressing ovarian cancer cells with magnolol down-regulated the HER-2 downstream PI3K/Akt signaling pathway, and suppressed the expression of downstream target genes, vascular endothelial growth factor (VEGF), matrix metalloproteinase 2 (MMP2) and cyclin D1. Consistently, magnolol-mediated inhibition of MMP2 activity could be prevented by co-treatment with epidermal growth factor. Migration assays revealed that magnolol treatment markedly reduced the motility of HER-2 overexpressing ovarian cancer cells. These findings suggest that magnolol may act against HER-2 and its downstream PI3K/Akt/mTOR-signaling network, thus resulting in suppression of HER-2mediated transformation and metastatic potential in HER-2 overexpressing ovarian cancers. These results provide a novel mechanism to explain the anti-cancer effect of magnolol (Chuang et al., 2011).

Lung Cancer

Magnolol has been found to inhibit cell growth, increase lactate dehydrogenase release, and modulate cell cycle in human lung carcinoma A549 cells. Magnolol induced the activation of caspase-3 and cleavage of Poly-(ADP)-ribose polymerase, and decreased the expression level of nuclear factor-κB/Rel A in the nucleus. In addition, magnolol inhibited basic fibroblast growth factor-induced proliferation and capillary tube formation of human umbilical vein endothelial cells. These data indicate that magnolol is a potential candidate for the treatment of human lung carcinoma (Seo et al., 2011).

Prostate Cancer; Anti-metastatic

Matrix metalloproteinases (MMPs) are enzymes involved in various steps of metastasis development. The objective of this study was to study the effects of magnolol on cancer invasion and metastasis using PC-3 human prostate carcinoma cells. Magnolol inhibited cell growth in a dose-dependent manner. In an invasion assay conducted in Transwell chambers, magnolol showed 33 and 98% inhibition of cancer cell at 10 microM and 20 microM concentrations, respectively, compared to the control. The protein and mRNA levels of both MMP-2 and MMP-9 were down-regulated by magnolol treatment in a dose-dependent manner.

These results demonstrate the anti-metastatic properties of magnolol in inhibiting the adhesion, invasion, and migration of PC-3 human prostate cancer cells (Hwang et al., 2010).

Glioblastoma Cancer

Magnolol has been found to concentration-dependently (0-40 microM) decrease the cell number in a cultured human glioblastoma cancer cell line (U373) and arrest the cells at the G0/G1 phase of the cell-cycle.

Pre-treatment of U373 with p21/Cip1 specific antisense oligodeoxynucleotide prevented the magnolol-induced increase of p21/Cip1 protein levels and the decrease of DNA synthesis. Magnolol at a concentration of 100 microM induced DNA fragmentation in U373. These findings suggest the potential applications of magnolol in the treatment of human brain cancers (Chen et al. 2011).

Inhibits Angiogenesis

Magnolol inhibited VEGF-induced Ras activation and subsequently suppressed extracellular signal-regulated kinase (ERK), phosphatidylinositol-3-kinase (PI3K)/Akt and p38, but not Src and focal adhesion kinase (FAK). Interestingly, the knockdown of Ras by short interfering RNA produced inhibitory effects that were similar to the effects of magnolol on VEGF-induced angiogenic signaling events, such as ERK and Akt/eNOS activation, and resulted in the inhibition of proliferation, migration, and vessel sprouting in HUVECs.

In combination, these results demonstrate that magnolol is an inhibitor of angiogenesis and suggest that this compound could be a potential candidate in the treatment of angiogenesis-related diseases (Kim et al., 2013).

References

Chen LC, Liu YC, Liang YC, Ho YS, Lee WS. (2009). Magnolol inhibits human glioblastoma cell proliferation through up-regulation of p21/Cip1. J Agric Food Chem, 57(16):7331-7. doi: 10.1021/jf901477g.


Chen MC, Lee CF, Huang WH, Chou TC. (2013). Magnolol suppresses hypoxia-induced angiogenesis via inhibition of HIF-1 α /VEGF signaling pathway in human bladder cancer cells. Biochem Pharmacol, 85(9):1278-87. doi: 10.1016/j.bcp.2013.02.009.


Chen SC, Chang YL, Wang DL, Cheng JJ. (2006). Herbal remedy magnolol suppresses IL-6-induced STAT3 activation and gene expression in endothelial cells. Br J Pharmacol, 148(2): 226–232. doi: 10.1038/sj.bjp.0706647


Chuang TC, Hsu SC, Cheng YT, et al. (2011). Magnolol down-regulates HER2 gene expression, leading to inhibition of HER2-mediated metastatic potential in ovarian cancer cells. Cancer Lett, 311(1):11-9. doi: 10.1016/j.canlet.2011.06.007.


Hwang ES, Park KK. (2010). Magnolol suppresses metastasis via inhibition of invasion, migration, and matrix metalloproteinase-2/-9 activities in PC-3 human prostate carcinoma cells. Biosci Biotechnol Biochem, 74(5):961-7.


Kim KM, Kim NS, Kim J, et al. (2013). Magnolol Suppresses Vascular Endothelial Growth Factor-Induced Angiogenesis by Inhibiting Ras-Dependent Mitogen-Activated Protein Kinase and Phosphatidylinositol 3-Kinase/Akt Signaling Pathways. Nutr Cancer.


Park JB, Lee MS, Cha EY, et al. (2012). Magnolol-induced apoptosis in HCT-116 colon cancer cells is associated with the AMP-activated protein kinase signaling pathway. Biol Pharm Bull, 35(9):1614-20.


Seo JU, Kim MH, Kim HM, Jeong HJ. (2011). Anti-cancer potential of magnolol for lung cancer treatment. Arch Pharm Res, 34(4):625-33. doi: 10.1007/s12272-011-0413-8.

Indirubin

Cancer:
Chronic myelogenous leukemia, lung, breast, head and neck, prostate, acute myeloid leukemia, prostate

Action: Aryl hydrocarbon Receptor (AhR) regulator, inhibits angiogenesis

Indirubin is the active component of many plants from the Isatis (L.) genus, including Isatis tinctoria (L.).

Indirubin is the active ingredient of Danggui Longhui Wan, a mixture of plants that is used in traditional Chinese medicine to treat chronic diseases. Indirubin and its analogues are potent inhibitors of cyclin-dependent kinases (CDKs). The crystal structure of CDK2 in complex with indirubin derivatives shows that indirubin interacts with the kinase's ATP-binding site through van der Waals interactions and three hydrogen bonds. Indirubin-3'-monoxime inhibits the proliferation of a large range of cells, mainly through arresting the cells in the G2/M phase of the cell-cycle. These results have implications for therapeutic optimization of indigoids (Hoessel et al., 1999).

Formula; Huang Lian (Rhizoma Coptidis Recens), Huang Qin (Radix Scutellariae Baicalensis), Huang Bai (Cortex Phellodendri), Zhi Zi (Fructus Gardeniae Jasminoidis), Dang Gui (Radix Angelicae Sinensis), Lu Hui (Herba Aloes), Long Dan Cao (Radix Gentianae Longdancao), Da Huang (Radix et Rhizoma Rhei), Mu Xiang (Radix Aucklandiae Lappae), Qing Dai (Indigo Pulverata Levis), She Xiang (Secretio Moschus)

Leukemia

Indirubin, a 3, 2' bisindole isomer of indigo was originally identified as the active principle of a traditional Chinese preparation and has been proven to exhibit anti-leukemic effectiveness in chronic myelocytic leukemia. Indirubin was detected to represent a novel lead structure with potent inhibitory potential towards cyclin-dependent kinases (CDKs) resulting from high affinity binding into the enzymes ATP binding site. This seminal finding triggered research to improve the pharmacological activities of the parent molecule within comprehensive structure-activity studies. Molecular modifications made novel anti-cancer compounds accessible with strongly improved CDK inhibitory potential and with broad-spectrum anti-tumor activity.

This novel family of compounds holds strong promise for clinical anti-cancer activity and might be useful also in several important non-cancer indications, including Alzheimer's disease or diabetes (Eisenbrand et al., 2004).

Aryl Hydrocarbon Receptor (AhR) Regulator; Breast Cancer

The aryl hydrocarbon receptor (AhR), when activated by exogenous ligands such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), regulates expression of several phase I and phase II enzymes and is also involved in the regulation of cell proliferation. One putative endogenous ligand is indirubin, which was recently identified in human urine and bovine serum. We determined the effect of indirubin in MCF-7 breast cancer cells on induction of the activities of cytochromes P450 (CYP) 1A1 and 1B1. With 4 hours exposure, the effects of indirubin and TCDD at 10nM on CYP activity were comparable, but the effects of indirubin, unlike those of TCDD, were transitory. Indirubin-induced ethoxyresorufin-O-deethylase activity was maximal by 6–9 hours post-exposure and had disappeared by 24 hours, whereas TCDD-induced activities remained elevated for at least 72 hours.

Thus, if indirubin is an endogenous AhR ligand, then AhR-mediated signaling by indirubin is likely to be transient and tightly controlled by the ability of indirubin to induce CYP1A1 and CYP1B1, and hence its own metabolism (Spink et al., 2003).

Chronic Myelogenous Leukemia (CML)

Indirubin is the major active anti-tumor component of a traditional Chinese herbal medicine used for treatment of chronic myelogenous leukemia (CML). In a study investigating its mechanism of action, indirubin derivatives (IRDs) were found to potently inhibit Signal Transducer and Activator of Transcription 5 (Stat5) protein in CML cells.

Compound E804, which is the most potent in this series of IRDs, blocked Stat5 signaling in human K562 CML cells, imatinib-resistant human KCL-22 CML cells expressing the T315I mutant Bcr-Abl (KCL-22M), and CD34-positive primary CML cells from patients.

In sum, these findings identify IRDs as potent inhibitors of the SFK/Stat5 signaling pathway downstream of Bcr-Abl, leading to apoptosis of K562, KCL-22M and primary CML cells. IRDs represent a promising structural class for development of new therapeutics for wild type or T315I mutant Bcr-Abl-positive CML patients (Nam et al., 2012).

Lung Cancer

A novel indirubin derivative, 5'-nitro-indirubinoxime (5'-NIO), exhibits a strong anti-cancer activity against human cancer cells. Here, the 5'-NIO-mediated G1 cell-cycle arrest in lung cancer cells was associated with a decrease in protein levels of polo-like kinase 1 (Plk1) and peptidyl-prolyl cis/trans isomerase Pin1. These findings suggest that 5'-NIO have potential anti-cancer efficacy through the inhibition of Plk1 or/and Pin1 expression (Yoon et al., 2012).

The control lung tissue showed a normal architecture with clear alveolar spaces. Interestingly, the indirubin-3-monoxime treated groups showed reduced adenocarcinoma with appearance of alveolar spaces. Transmission Electron Microscopic (TEM) studies of lung sections of [B(α)P]-induced lung cancer mice showed the presence of phaemorphic cells with dense granules and increased mitochondria.

The lung sections of mice treated with indirubin-3-monoxime showed the presence of shrunken, fragmented, and condensed nuclei implying apoptosis. The effects were dose-dependent and prominent in 10 mg/kg/5 d/week groups, suggesting the therapeutic role of indirubin analogue against this deadly human malignancy. These results indicate that indirubin-3-monoxime brings anti-tumor effect against [B(α)P]-induced lung cancer by its apoptotic action in A/J mice (Ravichandran et al., 2010).

Head and Neck Cancer

The effects of 5'-nitro-indirubinoxime (5'-NIO), an indirubin derivative, on metastasis of head and neck cancer cells were investigated and the underlying molecular mechanisms involved in this process explored.

After treatment of head and neck cancer cells with 5'-NIO, cell metastatic behaviors such as colony formation, invasion, and migration were inhibited in a concentration-dependent manner. 5'-NIO inhibited the beta1 Integrin/FAK/Akt pathway which can then facilitate invasion and/or migration of cancer cells through the extracellular matrix (ECM). Moreover, treatment of head and neck cancer cell with Integrin β1 siRNA or FAK inhibitor effectively inhibited the invasion and migration, suggesting their regulatory role in invasiveness and migration of head and neck cancer cells. It was concluded that 5'-NIO inhibits the metastatic ability of head and neck cancer cells by blocking the Integrin β1/FAK/Akt pathway (Kim et al., 2011).

Prostate Cancer; Inhibits Angiogenesis

Indirubin, the active component of a traditional Chinese herbal medicine, Banlangen, has been shown to exhibit anti-tumor and anti-inflammation effects; however, its role in tumor angiogenesis, the key step involved in tumor growth and metastasis, and the involved molecular mechanism is unknown.

To address this shortfall in the existing research, it was identified that indirubin inhibited prostate tumor growth through inhibiting tumor angiogenesis. It was found that indirubin inhibited angiogenesis in vivo. The inhibition activity of indirubin in endothelial cell migration, tube formation and cell survival in vitro has also been shown. Furthermore, indirubin suppressed vascular endothelial growth factor receptor 2-mediated Janus kinase (JAK)/STAT3 signaling pathway. This study provided the first evidence for anti-tumor angiogenesis activity of indirubin and the related molecular mechanism.

These investigations suggest that indirubin is a potential drug candidate for angiogenesis-related diseases (Zhang et al., 2011).

Acute Myeloid Leukemia

Indirubin derivatives were identified as potent FLT3 tyrosine kinase inhibitors with anti-proliferative activity at acute myeloid leukemic cell lines, RS4;11 and MV4;11 which express FLT3-WT and FLT3-ITD mutation, respectively. Among several 5 and 5'-substituted indirubin derivatives, 5-fluoro analog, 13 exhibited potent inhibitory activity at FLT3 (IC(50)=15 nM) with more than 100-fold selectivity versus 6 other kinases and potent anti-proliferative effect for MV4;11 cells (IC(50)=72 nM) with 30-fold selectivity versus RS4;11 cells.

Cell cycle analysis indicated that compound 13 induced cell-cycle arrest at G(0)/G(1) phase in MV4;11 cells (Choi et al., 2010).

References

Choi SJ, Moon MJ, Lee SD, et al. (2010). Indirubin derivatives as potent FLT3 inhibitors with anti-proliferative activity of acute myeloid leukemic cells. Bioorg Med Chem Lett, 20(6):2033-7.


Eisenbrand G, Hippe F, Jakobs S, Muehlbeyer S. (2004). Molecular mechanisms of indirubin and its derivatives: novel anti-cancer molecules with their origin in traditional Chinese phytomedicine. J Cancer Res Clin Oncol, 130(11):627-35


Hoessel R, Leclerc S, Endicott JA, et al. (1999). Indirubin, the active constituent of a Chinese antileukaemia medicine, inhibits cyclin-dependent kinases. Nat Cell Biol, 1(1):60-7.


Kim SA, Kwon SM, Kim JA, et al. (2011). 5'-Nitro-indirubinoxime, an indirubin derivative, suppresses metastatic ability of human head and neck cancer cells through the inhibition of Integrin β 1/FAK/Akt signaling. Cancer Lett, 306(2):197-204.


Nam S, Scuto A, Yang F, et al. (2012). Indirubin derivatives induce apoptosis of chronic myelogenous leukemia cells involving inhibition of Stat5 signaling. Mol Oncol, 6(3):276-83.


Ravichandran K, Pal A, Ravichandran R. (2010). Effect of indirubin-3-monoxime against lung cancer as evaluated by histological and transmission electron microscopic studies. Microsc Res Tech, 73(11):1053-8.


Spink BC, Hussain MM, Katz BH, Eisele L, Spink DC. (2003). Transient induction of cytochromes P450 1A1 and 1B1 in MCF-7 human breast cancer cells by indirubin. Biochem Pharmacol, 66(12):2313-21.


Yoon HE, Kim SA, Choi HS, et al. (2012). Inhibition of Plk1 and Pin1 by 5'-nitro-indirubinoxime suppresses human lung cancer cells. Cancer Lett, 316(1):97-104.


Zhang X, Song Y, Wu Y, et al. (2011). Indirubin inhibits tumor growth by anti-tumor angiogenesis via blocking VEGFR2-mediated JAK/STAT3 signaling in endothelial cell. Int J Cancer, 129(10):2502-11. doi: 10.1002/ijc.25909.

Icaritin

Cancer:
Endometrial., chronic myeloid leukemia, prostate, breast

Action: Radio-sensitizer, cell-cycle arrest, ER modulator

Icaritin is a compound in several species of the genus Epimedium (L.).

Cell-cycle Arrest

Icariin and icaritin with prenyl group have been demonstrated to have selective estrogen receptor modulating activities. Icaritin-induced growth inhibition was associated with G(1) arrest (P<0.05), and G(2)-M arrest depending upon doses. Consistent with G(1) arrest, icaritin increased protein expressions of pRb, p27(Kip1) and p16(Ink4a), while showing decrease in phosphorylated pRb, Cyclin D1 and CDK4.

Comparatively, icariin has much lower effects on PC-3 cells and showed only weak G(1) arrest, suggesting a possible structure-activity relationship. These findings suggested a novel anti-cancer efficacy of icaritin mediated selectively via induction of cell-cycle arrest but not associated with estrogen receptors in PC-3 cells (Huang et al., 2007).

Estrogen Receptor (ER) Modulator; Endometrial Cancer

Icaritin has selective estrogen receptor (ER) modulating activities, and posseses anti-tumor activity. The effect of icaritin on cell growth of human endometrial cancer Hec1A cells was investigated and it was found that icaritin potently inhibited proliferation of Hec1A cells. Icaritin also induced cell apoptosis accompanied by activation of caspases. Icaritin treatment also induced expression of pro-apoptotic protein Bax with a concomitant decrease of Bcl-2 expression.

These results demonstrate that icaritin induced sustained ERK 1/2 activation and inhibited growth of endometrial cancer Hec1A cells, and provided a rationale for preclinical and clinical evaluation of icaritin for endometrial cancer therapy (Tong et al., 2011).

Breast cancer

In research carried out to probe breast cancer cell growth mechanisms, icaritin has been found to strongly inhibit the growth of breast cancer MDA-MB-453 and MCF7 cells. At concentrations of 2–3 µM, icaritin induced cell-cycle arrest at the G2/M phase accompanied by a down-regulation of the expression levels of the G2/M regulatory proteins such as cyclinB, cdc2 and cdc25C.

Icaritin at concentrations of 4–5 µM, however, induced apoptotic cell death. In addition, icaritin also induced a sustained phosphorylation of extracellular signal-regulated kinase (ERK) in these breast cancer cells.

Icaritin more potently inhibited growth of the breast cancer stem/progenitor cells compared to anti-estrogen tamoxifen. These results indicate that icaritin is a potent growth inhibitor for breast cancer cells and provides a rationale for preclinical and clinical evaluations of icaritin for breast cancer therapy (Guo et al., 2011).

Radio-sensitizer

The combination of Icaritin at 3 µM or 6 µM with 6 or 8 Gy of ionizing radiation (IR) in the clonogenic assay yielded an ER (enhancement ratio) of 1.18 or 1.28, CI (combination index) of 0.38 or 0.19 and DRI (dose reducing index) of 2.51 or 5.07, respectively. These findings strongly suggest that Icaritin exerted a synergistic killing effect with radiation on the tumor cells. It suppressed angiogenesis in chick embryo chorioallantoic membrane (CAM) assay. These results, taken together, indicate Icaritin is a new radio-sensitizer and can enhance anti-cancer effect of IR or other therapies (Hong et al., 2013).

Chronic Myeloid Leukemia (CML)

The mechanism of anti-leukemia for Icaritin is involved in the regulation of Bcr/Abl downstream signaling. Icaritin may be useful for an alternative therapeutic choice of Imatinib-resistant forms of CML. Icaritin potently inhibited proliferation of K562 cells (IC50 was 8 µM) and primary CML cells (IC50 was 13.4 µM for CML-CP and 18 µM for CML-BC), induced CML cells apoptosis, and promoted the erythroid differentiation of K562 cells in a time-dependent manner. Furthermore, Icaritin was able to suppress the growth of primary CD34+ leukemia cells (CML) and Imatinib-resistant cells, and to induce apoptosis (Zhu et al., 2011).

References

Guo YM, Zhang XT, Meng J, Wang ZY. (2011). An anti-cancer agent icaritin induces sustained activation of the extracellular signal-regulated kinase (ERK) pathway and inhibits growth of breast cancer cells. European Journal of Pharmacology, 658(2–3):114–122. doi:10.1016/j.ejphar.2011.02.005.


Hong J, Zhang Z, Lv W, et al. (2013). Icaritin Synergistically Enhances the Radiosensitivity of 4T1 Breast Cancer Cells. PLoS One, 8(8):e71347. doi: 10.1371/journal.pone.0071347.


Huang X, Zhu D, Lou Y. (2007). A novel anti-cancer agent, icaritin, induced cell growth inhibition, G1 arrest and mitochondrial transmembrane potential drop in human prostate carcinoma PC-3 cells. Eur J Pharmacol, 564(1-3):26-36.


Tong JS, Zhang QH, Huang X, et al. (2011). Icaritin Causes Sustained ERK1/2 Activation and Induces Apoptosis in Human Endometrial Cancer Cells. PLoS ONE, 6(3): e16781. doi:10.1371/journal.pone.0016781.


Zhu JF, Li ZJ, Zhang GS, et al. (2011). Icaritin shows potent anti-leukemia activity on chronic myeloid leukemia in vitro and in vivo by regulating MAPK/ERK/JNK and JAK2/STAT3 /AKT signalings. PLoS One, 6(8):e23720. doi: 10.1371/journal.pone.0023720.

I3C

Cancer: Prostate

Action: Inhibits telomerase activity, anti-cancer

Indole-3-carbinol (I3C) is a phytochemical with anti-carcinogenic properties. Telomerase activity is key in carcinogenesis. The effect of I3C on telomerase was investigated in human prostate cancer cell lines LNCaP and PC3. Cells were treated with I3C at 100 and 250 µM with and without 10-50 µM diethylstilbestrol (DES). Telomerase activity was performed using TRAPaze Telomerase Detection Kit, and hTERT gene expression by real time quantitative RT-PCR. I3C (250 µM) inhibited telomerase activity and mRNA expression of hTERT in LNCaP and PC3 cells. I3C at 250 µM combined with any concentration of DES was cytotoxic to LNCaP. Telomerase activity in PC3 cells with 250 µM of I3C and 25 or 50 µM of DES was significantly reduced or inhibited, respectively.

I3C combined with DES reduced PC3 viability and eliminated LNCaP cells. I3C significantly inhibited telomerase activity and hTERT mRNA expression in LNCaP and PC3 cells. Combination of I3C and DES enhanced the inhibitory effect on telomerase activity, gene expression, and cell viability. These results implied that I3C and DES combined might help in prostate cancer treatment (Adler et al., 2011).

Reference

Adler S, Rashid G, Klein A. (2011). Indole-3-carbinol inhibits telomerase activity and gene expression in prostate cancer cell lines. Anti-cancer Res, 31(11):3733-7.

Hispolon

Cancer: Bladder, breast, liver, gastric

Action: Anti-inflammatory, cytostatic, cytotoxic, pro-oxidative, anti-proliferative

Hispolon is an active phenolic compound of Phellinus igniarius , a mushroom that has recently been shown to have anti-oxidant, anti-inflammatory, and anti-cancer activities.

Liver Cancer

Hispolon inhibited cellular growth of Hep3B cells in a time-dependent and dose-dependent manner, through the induction of cell-cycle arrest at S phase measured using flow cytometric analysis and apoptotic cell death, as demonstrated by DNA laddering. Exposure of Hep3B cells to hispolon resulted in apoptosis as evidenced by caspase activation, PARP cleavage, and DNA fragmentation. Hispolon treatment also activated JNK, p38 MAPK, and ERK expression. Inhibitors of ERK (PB98095), but not those of JNK (SP600125) and p38 MAPK (SB203580), suppressed hispolon-induced S-phase arrest and apoptosis in Hep3B cells.

These findings establish a mechanistic link between the MAPK pathway and hispolon-induced cell-cycle arrest and apoptosis in Hep3B cells (Huang et al., 2011).

Gastric Cancer, Breast Cancer, Bladder Cancer

Hispolon extracted from Phellinus species was found to induce epidermoid and gastric cancer cell apoptosis. Hispolon has also been found to inhibit breast and bladder cancer cell growth, regardless of p53 status. Furthermore, p21(WAF1), a cyclin-dependent kinase inhibitor, was elevated in hispolon-treated cells. MDM2, a negative regulator of p21(WAF1), was ubiquitinated and degraded after hispolon treatment.

Lu et al. (2009) also found that activated ERK1/2 (extracellular signal-regulated kinase1/2) was recruited to MDM2 and involved in mediating MDM2 ubiquitination. The results indicated that cells with higher ERK1/2 activity were more sensitive to hispolon. In addition, hispolon-induced caspase-7 cleavage was inhibited by the ERK1/2 inhibitor, U0126.

In conclusion, hispolon ubiquitinates and down-regulates MDM2 via MDM2-recruited activated ERK1/2. Therefore, hispolon may be a potential anti-tumor agent in breast and bladder cancers.

Gastric Cancer

The efficacy of hispolon in human gastric cancer cells and cell death mechanism was explored. Hispolon induced ROS-mediated apoptosis in gastric cancer cells and was more toxic toward gastric cancer cells than toward normal gastric cells, suggesting greater susceptibility of the malignant cells.

The mechanism of hispolon-induced apoptosis was that hispolon abrogated the glutathione anti-oxidant system and caused massive ROS accumulation in gastric cancer cells. Excessive ROS caused oxidative damage to the mitochondrial membranes and impaired the membrane integrity, leading to cytochrome c release, caspase activation, and apoptosis. Furthermore, hispolon potentiated the cytotoxicity of chemotherapeutic agents used in the clinical management of gastric cancer.

These results suggest that hispolon could be useful for the treatment of gastric cancer either as a single agent or in combination with other anti-cancer agents (Chen et al., 2008).

Anti-proliferative Activity

Hispolon, which lacks one aromatic unit in relation to curcumin, exhibits enhanced anti-inflammatory and anti-proliferative activities. Dehydroxy hispolon was least potent for all three activities. Overall the results indicate that the substitution of a hydroxyl group for a methoxy group at the meta positions of the phenyl rings in curcumin significantly enhanced the anti-inflammatory activity, and the removal of phenyl ring at the 7(th) position of the heptadiene back bone and addition of hydroxyl group significantly increased the anti-proliferative activity of curcumin and hispolon (Ravindran et al., 2010).

References

Chen W, Zhao Z, Li L, et al. (2008). Hispolon induces apoptosis in human gastric cancer cells through a ROS-mediated mitochondrial pathway. Free Radic Biol Med, 45(1):60-72. doi: 10.1016/j.freeradbiomed.2008.03.013.


Huang GJ, Deng JS, Huang SS, Hu ML. (2011). Hispolon induces apoptosis and cell-cycle arrest of human hepatocellular carcinoma Hep3B cells by modulating ERK phosphorylation. J Agric Food Chem, 59(13):7104-13. doi: 10.1021/jf201289e.


Lu TL, Huang GJ, Lu TJ, et al. (2009). Hispolon from Phellinus linteus has anti-proliferative effects via MDM2-recruited ERK1/2 activity in breast and bladder cancer cells. Food Chem Toxicol, 47(8):2013-21. doi: 10.1016/j.fct.2009.05.023.


Ravindran J, Subbaraju GV, Ramani MV, et al. (2010). Bisdemethylcurcumin and structurally related hispolon analogues of curcumin exhibit enhanced prooxidant, anti-proliferative and anti-inflammatory activities in vitro. Biochem Pharmacol, 79(11):1658-66. doi: 10.1016/j.bcp.2010.01.033.

Hedyotis Diffusa Extract

Cancer: Colon

Action: CYP3A4 induction, inhibits angiogenesis

Hedyotis diffusa is a herb native to East Asia, particularly China, Japan, and Nepal.

Inhibition of tumor angiogenesis has become an attractive target of anti-cancer chemotherapy. However, drug resistance and cytotoxicity against non-tumor-associated endothelial cells limit the long-term use and the therapeutic effectiveness of angiogenesis inhibitors, thus increasing the necessity for the development of multi-target agents with minimal side effects. Hedyotis Diffusa Willd (EEHDW) has long been used as an important component in several TCM formulas to treat various types of cancer.

Inhibits Angiogenesis

The angiogenic effects of the ethanol extract of EEHDW were investigated, in order to find a molecular mechanism for its anti-cancer activity. It was found that EEHDW inhibited angiogenesis in vivo in chick embryo chorioallantoic membrane (CAM). In addition, EEHDW dose- and time-dependently inhibited the proliferation of human umbilical vein endothelial cells (HUVEC) by blocking the cell-cycle G1 to S progression.

Moreover, EEHDW inhibited the migration and tube formation of HUVECs. Furthermore, EEHDW treatment down-regulated the mRNA and protein expression levels of VEGF-A in HT-29 human colon carcinoma cells and HUVECs. These findings suggest that inhibiting tumor angiogenesis is one of the mechanisms by which EEHDW is involved in cancer therapy (Lin et al., 2011).

Colorectal Cancer

Hedyotis diffusa Willd has been used as a major component in several Chinese medicine formulas for the clinical treatment of colorectal cancer (CRC). The ethanol extract of Hedyotis diffusa Willd (EEHDW) reduced tumor volume and tumor weight, and suppressed STAT3 phosphorylation in tumor tissues, which in turn resulted in the promotion of cancer cell apoptosis and inhibition of proliferation. Moreover, EEHDW treatment altered the expression pattern of several important target genes of the STAT3 signaling pathway, i.e., decreased expression of Cyclin D1, CDK4 and Bcl-2 as well as up-regulated p21 and Bax (Cai et al., 2012).

EEHDW reduced HT-29 cell viability and survival in a dose- and time-dependent manner. Lin et al. (2012) observed that EEHDW treatment blocked the cell-cycle, preventing G1 to S progression, and reduced mRNA expression of pro-proliferative PCNA, Cyclin D1 and CDK4, but increased that of anti-proliferative p21 (Lin et al., 2012).

Recently, Lin et al. (2013) reported that HDW could inhibit colorectal cancer growth in vivo and in vitro via suppression of the STAT3 pathway. EEHDW could significantly reduce intratumoral microvessel density (MVD), indicating its activity of anti-tumor angiogenesis in vivo. EEHDW suppressed the activation of SHH signaling in CRC xenograft tumors since it significantly decreased the expression of key mediators of SHH pathway. EEHDW treatment inhibited the expression of the critical SHH signaling target gene VEGF-A as well as its specific receptor VEGFR2 (Lin et al., 2013).

CYP3A4 Induction

Patients are warned against the concomitant use of Oldenlandia diffusa and Rehmannia glutinosa, which could result in induction of CYP3A4, leading to a reduced efficacy of drugs that are CYP3A4 substrates and have a narrow therapeutic window (Lau et al., 2013).

References

Cai Q, Lin J, Wei L, Zhang L, et al. (2012). Hedyotis diffusa Willd Inhibits Colorectal Cancer Growth in Vivo via Inhibition of STAT3 Signaling Pathway. Int J Mol Sci, 13(5):6117-28. doi: 10.3390/ijms13056117.


Lau C, Mooiman KD, Maas-Bakker RF, et al. (2013). Effect of Chinese herbs on CYP3A4 activity and expression in vitro. J Ethnopharmacol, 149(2):543-9. doi: 10.1016/j.jep.2013.07.014.


Lin J, Wei L, Xu W, et al. (2011). Effect of Hedyotis Diffusa Willd extract on tumor angiogenesis. Mol Med Report, 4(6):1283-8. doi: 10.3892/mmr.2011.577.


Lin M, Lin J, Wei L, et al. (2012). Hedyotis diffusa Willd extract inhibits HT-29 cell proliferation via cell-cycle arrest. Exp Ther Med, 4(2):307-310.


Lin J, Wei L, Shen A, et al. (2013). Hedyotis diffusa Willd extract suppresses Sonic hedgehog signaling leading to the inhibition of colorectal cancer angiogenesis. Int J Oncol, 42(2):651-6. doi: 10.3892/ijo.2012.1753.

Glabridin

Cancer: Breast

Action: Inhibits metastasis, inhibits angiogenesis

Glabridin is a novel phytoestrogen isolated from licorice extract (Glycyrrhiza glabra (L.))

Breast Cancer Growth; Estrogen agonist

Glabridin and its derivatives bind to the human ER and have been found to act as an estrogen agonist in the induction of an estrogen response marker, such as CK activity, in vivo, to induce uterus wet weight, and to stimulate human breast cancer cell growth. There is an increasing demand for natural compounds that improve women's health by mimicking the critical benefits of estrogen to the bones and the cardiovascular system but avoiding its deleterious effects on the breast and uterus.

The estrogenic properties of glabridin, the major isoflavan in licorice root, were tested in view of the resemblance of its structure and lipophilicity to those of estradiol. The results indicate that glabridin is a phytoestrogen, binding to the human estrogen receptor and stimulating creatine kinase activity in rat uterus, epiphyseal cartilage, diaphyseal bone, aorta, and left ventricle of the heart. This indicates that isoflavans have estrogen-like activities. Glabridin and its derivatives exhibited varying degrees of estrogen receptor agonism in different tests and demonstrated growth-inhibitory actions on breast cancer cells (Tamir et al., 2000).

Inhibits Metastasis, Inhibits Angiogenesis

Glabridin exhibited effective inhibition of cell metastasis by decreasing cancer cell migration and invasion of metastatic MDA-MB-231 breast cancer cells. In addition, glabridin also blocked human umbilical vein endothelial cells (HUVEC) migration and decreased MDA-MB-231-mediated angiogenesis. Further investigation revealed that the inhibition of cancer angiogenesis by glabridin was also evident in a nude mice model. Blockade of MDA-MB-231 cells and HUVEC migration was associated with an increase of αγβ3 integrin proteosome degradation. Glabridin also decreased the active forms of FAK and Src, and enhanced levels of inactivated phosphorylated Src (Tyr 416), decreasing the interaction of FAK and Src.

Inhibition of the FAK/Src complex by glabridin also blocked AKT and ERK1/2 activation, resulting in reduced activation of RhoA as well as myosin light chain phosphorylation. This study demonstrates that glabridin may be a novel anti-cancer agent for the treatment of breast cancer in three different ways: inhibition of migration, invasion and angiogenesis (Hsu et al., 2011).

References

Hsu YL, Wu LY, Hou MF, et al. (2011). Glabridin, an isoflavan from licorice root, inhibits migration, invasion and angiogenesis of MDA-MB-231 human breast adenocarcinoma cells by inhibiting focal adhesion kinase/Rho signaling pathway. Molecular Nutrition & Food Research, 55(2):318–27. doi: 10.1002/mnfr.201000148.


Tamir S, Eizenberg M, Somjen D, et al. (2000). Estrogenic and Anti-proliferative Properties of Glabridin from Licorice in Human Breast Cancer Cells. Cancer Res, 60:5704

Eugenol

Cancer:
Melanoma, osteosarcoma, leukemia, gastric, colon, liver, oral., lung

Action: Radio-protective

Eugenol is a natural compound available in honey and various plants extracts; in particular, cloves (Syzygium aromaticum (L.) Merrill & Perry).

Melanoma, Skin Tumors, Osteosarcoma, Leukemia, Gastric Cancer

Eugenol (4-allyl-2-methoxyphenol), a phenolic phytochemicals, is the active component of Syzigium aromaticum (cloves). Aromatic plants like nutmeg, basil, cinnamon and bay leaves also contain eugenol. Eugenol has a wide range of applications like perfumeries, flavorings, essential oils and in medicine as a local antiseptic and anesthetic. Increasing volumes of literature show eugenol possesses anti-oxidant, anti-mutagenic, anti-genotoxic, anti-inflammatory and anti-cancer properties.

The molecular mechanism of eugenol-induced apoptosis in melanoma, skin tumors, osteosarcoma, leukemia, gastric and mast cells has been well documented and highlights the anti-proliferative activity and molecular mechanism of eugenol-induced apoptosis against the cancer cells and animal model (Jaganathan et al., 2012).

Colon Cancer

Since most of the drugs used in cancer are apoptosis-inducers, the apoptotic effect and anti-cancer mechanism of eugenol were investigated against colon cancer cells. MTT assay signified the anti-proliferative nature of eugenol against the tested colon cancer cells. PI staining indicated increasing accumulation of cells at sub-G1-phase. Eugenol treatment resulted in reduction of intracellular non-protein thiols and increase in the earlier lipid layer break. Further events like dissipation of MMP and generation of ROS (reactive oxygen species) were accompanied in the eugenol-induced apoptosis. Augmented ROS generation resulted in the DNA fragmentation of treated cells as shown by DNA fragmentation and TUNEL assay. Further activation of PARP (polyadenosine diphosphate-ribose polymerase), p53 and caspase-3 were observed in Western blot analyzes.

These results demonstrate the molecular mechanism of eugenol-induced apoptosis in human colon cancer cells. This research will further enhance eugenol as a potential chemo-preventive agent against colon cancer (Jaganathan et al., 2011).

Radio-protective, Skin Cancer, Liver Cancer, Oral Cancer, Lung Cancer

Ocimum sanctum L. or Ocimum tenuiflorum L , commonly known as Holy Basil in English or Tulsi in the various Indian languages, is an important medicinal plant in the various traditional and folk systems of medicine in Southeast Asia, and another plant from which eugenol is extracted. Scientific studies have shown it to possess anti-inflammatory, analgesic, anti-pyretic, anti-diabetic, hepato-protective, hypolipidemic, anti-stress, and immunomodulatory activities. Preclinical studies have also shown that Ocimum and some of its phytochemicals including eugenol prevented chemical-induced skin, liver, oral., and lung cancers and to mediate these effects by increasing the anti-oxidant activity, altering the gene expressions, inducing apoptosis, and inhibiting angiogenesis and metastasis.

The aqueous extract of Ocimum and its flavanoids, orintin and vicenin, are shown to protect mice against γ-radiation-induced sickness and mortality and to selectively protect the normal tissues against the tumoricidal effects of radiation. This action is related to the important phytochemicals it contains like eugenol, which are also shown to prevent radiation-induced DNA damage.

References

Baliga MS, Jimmy R, Thilakchan KR, et al. (2013). Ocimum sanctum L (Holy Basil or Tulsi) and its phytochemicals in the prevention and treatment of cancer. Nutr Cancer, 65(1):26-35. doi: 10.1080/01635581.2013.785010.


Jaganathan SK, Mazumdar A, Mondhe D, Mandal M. (2011). Apoptotic effect of eugenol in human colon cancer cell lines. Cell Biol Int, 35(6):607-15. doi: 10.1042/CBI20100118.


Jaganathan SK, Supriyanto E. (2012). Anti-proliferative and Molecular Mechanism of Eugenol-Induced Apoptosis in Cancer Cells. Molecules, 17(6):6290-6304. doi:10.3390/molecules17066290.

EGCG, ECG, CG, EC

Cancer: Breast, pancreatic, lung, colorectal

Action: Chemo-preventive effects, metastasis

(-)-Epigallocatechin gallate (EGCG) is isolated from Camellia sinensis [(L.) Kuntze].

Epidemiological evidence suggests tea (Camellia sinensis L.) has chemo-preventive effects against various tumors. (-)-Epigallocatechin gallate (EGCG), a catechin polyphenol compound, represents the main ingredient of green tea extract and is chemo-preventive and an anti-oxidant. EGCG shows growth inhibition of various cancer cell lines, such as lung, mammary, and stomach.

Breast Cancer, Colorectal Cancer

Although EGCG has been shown to be growth-inhibitory in a number of tumor cell lines, it is not clear whether the effect is cancer-specific. The effect of EGCG on the growth of SV40 virally transformed WI38 human fibroblasts (WI38VA) was compared with that of normal WI38 cells. The IC50 value of EGCG was estimated to be 120 and 10 microM for WI38 and WI38VA cells, respectively. Similar differential growth inhibition was also observed between a human colorectal cancer cell line (Caco-2), a breast cancer cell line (Hs578T) and their respective normal counterparts.

EGCG at a concentration range of 40-200 microM induced a significant amount of apoptosis in WI38VA cultures, but not in WI38 cultures, as determined by terminal deoxynucleotidyl transferase assay. It is possible that differential modulation of certain genes, such as c-fos and c-myc, may cause differential effects of EGCG on the growth and death of cancer cells (Chen et al., 1998).

Breast Cancer

Green tea contains many polyphenols, including epigallocatechin-3 gallate (EGCG), which possess anti-oxidant qualities. Reduction of chemically-induced mammary gland carcinogenesis by green tea in a carcinogen-induced rat model has been suggested previously, but the results reported were not statistically significant. Green tea significantly increased mean latency to the first tumor, and reduced tumor burden and number of invasive tumors per tumor-bearing animal; however, it did not affect tumor number in female rats.

Furthermore, we show that proliferation and/or viability of cultured Hs578T and MDA-MB-231 estrogen receptor-negative breast cancer cell lines was reduced by EGCG treatment. Similar negative effects on proliferation were observed with the DMBA-transformed D3-1 cell line. Growth inhibition of Hs578T cells correlated with induction of p27Kip1 cyclin-dependent kinase inhibitor (CKI) expression.

Thus, green tea had significant chemo-preventive effects on carcinogen-induced mammary tumorigenesis in female S-D rats. In culture, inhibition of human breast cancer cell proliferation by EGCG was mediated in part via induction of the p27Kip1 (Kavanagh et al., 2001).

Pancreatic Cancer

The in vitro anti-tumoral properties of EGCG were investigated in human PDAC (pancreatic ductal adenocarcinoma) cells PancTu-I, Panc1, Panc89 and BxPC3 in comparison with the effects of two minor components of green tea catechins, catechin gallate (CG) and epicatechin gallate (ECG). It was found that all three catechins inhibited proliferation of PDAC cells in a dose- and time-dependent manner.

Interestingly, CG and ECG exerted much stronger anti-proliferative effects than EGCG. Importantly, catechins, in particular ECG, inhibited TNFα-induced activation of NF-κB and consequently secretion of pro-inflammatory and invasion promoting proteins like IL-8 and uPA.

Overall, these data show that green tea catechins ECG and CG exhibit potent and much stronger anti-proliferative and anti-inflammatory activities on PDAC cells than the most studied catechin EGCG (KŸrbitz et al., 2011).

Okabe et al. (1997) assessed the ability of EGCG to inhibit HGF signaling in the immortalized, nontumorigenic breast cell line, MCF10A, and the invasive breast carcinoma cell line, MDA-MB-231. The ability of alternative green tea catechins to inhibit HGF-induced signaling and motility was investigated. (-)-Epicatechin-3-gallate (ECG) functioned similarly to EGCG by completely blocking HGF-induced signaling as low as 0.6 muM and motility at 5 muM in MCF10A cells; whereas, (-)-epicatechin (EC) was unable to inhibit HGF-induced events at any concentration tested. (-)-Epigallocatechin (EGC), however, completely repressed HGF-induced AKT and ERK phosphorylation at concentrations of 10 and 20 muM, but was incapable of blocking Met activation. Despite these observations, EGC did inhibit HGF-induced motility in MCF10A cells at 10 muM.

Metastsis Inhibition

These observations suggest that the R1 galloyl and the R2 hydroxyl groups are important in mediating the green tea catechins' inhibitory effect towards HGF/Met signaling. These combined in vitro studies reveal the possible benefits of green tea polyphenols as cancer therapeutic agents to inhibit Met signaling and potentially block invasive cancer growth (Bigelow et al., 2006).

Colorectal Cancer

Panaxadiol (PD) is a purified sapogenin of ginseng saponins, which exhibits anti-cancer activity. Epigallocatechin gallate (EGCG), a major catechin in green tea, is a strong botanical anti-oxidant. Effects of selected compounds on HCT-116 and SW-480 human colorectal cancer cells were evaluated by a modified trichrome stain cell proliferation analysis. Cell-cycle distribution and apoptotic effects were analyzed by flow cytometry after staining with PI/RNase or annexin V/PI. Cell growth was suppressed after treatment with PD (10 and 20  µm) for 48 h. When PD (10 and 20  µm) was combined with EGCG (10, 20, and 30  µm), significantly enhanced anti-proliferative effects were observed in both cell lines.

Combining 20  µm of PD with 20 and 30   µm of EGCG significantly decreased S-phase fractions of cells. In the apoptotic assay, the combination of PD and EGCG significantly increased the percentage of apoptotic cells compared with PD alone (p  < 0.01).

Data from this study suggested that apoptosis might play an important role in the EGCG-enhanced anti-proliferative effects of PD on human colorectal cancer cells (Du et al., 2013).

Action: Anti-inflammatory, antioxidant

Green tea catechins, especially epigallocatechin-3-gallate (EGCG), have been associated with cancer prevention and treatment. This has resulted in an increased number of studies evaluating the effects derived from the use of this compound in combination with chemo/radiotherapy. Most of the studies on this subject up to date are preclinical. Relevance of the findings, impact factor, and date of publication were critical parameters for the studies to be included in the review.

Additive and synergistic effects of EGCG when combined with conventional cancer therapies have been proposed, and its anti-inflammatory and antioxidant activities have been related to amelioration of cancer therapy side effects. However, antagonistic interactions with certain anticancer drugs might limit its clinical use.

The use of EGCG could enhance the effect of conventional cancer therapies through additive or synergistic effects as well as through amelioration of deleterious side effects. Further research, especially at the clinical level, is needed to ascertain the potential role of EGCG as adjuvant in cancer therapy.

Cancer: Pancreatic ductal adenocarcinoma

Action: Anti-proliferative and anti-inflammatory

In the present study, Kürbitz et al., (2011) investigated the in vitro anti-tumoral properties of EGCG on human PDAC (pancreatic ductal adenocarcinoma) cells PancTu-I, Panc1, Panc89 and BxPC3 in comparison with the effects of two minor components of green tea catechins catechin gallate (CG) and epicatechin gallate (ECG). We found that all three catechins inhibited proliferation of PDAC cells in a dose- and time-dependent manner. Interestingly, CG and ECG exerted much stronger anti-proliferative effects than EGCG. Western blot analyses performed with PancTu-I cells revealed catechin-mediated modulation of cell cycle regulatory proteins (cyclins, cyclin-dependent kinases [CDK], CDK inhibitors). Again, these effects were clearly more pronounced in CG or ECG than in EGCG treated cells. Importantly, catechins, in particular ECG, inhibited TNFα-induced activation of NF-κB and consequently secretion of pro-inflammatory and invasion promoting proteins like IL-8 and uPA. Overall, our data show that green tea catechins ECG and CG exhibit potent and much stronger anti-proliferative and anti-inflammatory activities on PDAC cells than the most studied catechin EGCG.

References

Bigelow RLH, & Cardelli JA. (2006). The green tea catechins, (-)-Epigallocatechin-3-gallate (EGCG) and (-)-Epicatechin-3-gallate (ECG), inhibit HGF/Met signaling in immortalized and tumorigenic breast epithelial cells. Oncogene, 25:1922–1930. doi:10.1038/sj.onc.1209227

Chen ZP, Schell JB, Ho CT, Chen KY. (1998). Green tea epigallocatechin gallate shows a pronounced growth-inhibitory effect on cancerous cells but not on their normal counterparts. Cancer Lett,129(2):173-9.


Du GJ, Wang CZ, Qi LW, et al. (2013). The synergistic apoptotic interaction of panaxadiol and epigallocatechin gallate in human colorectal cancer cells. Phytother Res, 27(2):272-7. doi: 10.1002/ptr.4707.


Kavanagh KT, Hafer LJ, Kim DW, et al. (2001). Green tea extracts decrease carcinogen-induced mammary tumor burden in rats and rate of breast cancer cell proliferation in culture. Journal of Cellular Biochemistry, 82(3):387-98. doi:10.1002/jcb.1164


KŸrbitz C, Heise D, Redmer T, et al. (2011). Epicatechin gallate and catechin gallate are superior to epigallocatechin gallate in growth suppression and anti-inflammatory activities in pancreatic tumor cells. Cancer Science, 102(4):728-734. doi: 10.1111/j.1349-7006.2011.01870.x


Okabe S, Suganuma M, Hayashi M, et al. (1997). Mechanisms of Growth Inhibition of Human Lung Cancer Cell Line, PC-9, by Tea Polyphenols. Cancer Science, 88(7):639–643. doi: 10.1111/j.1349-7006.1997.tb00431.x

Lecumberri E, Dupertuis YM, Miralbell R, Pichard C. (2013) Green tea polyphenol epigallocatechin-3-gallate (EGCG) as adjuvant in cancer therapy. Clinical Nutrition. Volume 32, Issue 6, December 2013, Pages 894–903.

Kürbitz C, Heise D, Redmer T, Goumas F, et al. Cancer Science. Online publication Jan 2011. DOI: 10.1111/j.1349-7006.2011.01870.x

Dietary Flavones

Cancer:
Prostate, colorectal., breast, pancreatic, bladder, ovarian, leukemia, liver, glioma, osteosarcoma, melanoma

Action: Anti-inflammatory, TAM resistance, cancer stem cells, down-regulate COX-2, apoptosis, cell-cycle arrest, anti-angiogenic, chemo-sensitzer, adramycin (ADM) resistance

Sulforaphane, Phenethyl isothiocyanate (PEITC), quercetin, epicatechin, catechin, Luteolin, apigenin

Anti-inflammatory

The anti-inflammatory activities of celery extracts, some rich in flavone aglycones and others rich in flavone glycosides, were tested on the inflammatory mediators tumor necrosis factor α (TNF-α) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in lipopolysaccharide-stimulated macrophages. Pure flavone aglycones and aglycone-rich extracts effectively reduced TNF-α production and inhibited the transcriptional activity of NF-κB, while glycoside-rich extracts showed no significant effects.

Celery diets with different glycoside or aglycone contents were formulated and absorption was evaluated in mice fed with 5% or 10% celery diets. Relative absorption in vivo was significantly higher in mice fed with aglycone-rich diets as determined by HPLC-MS/MS (where MS/MS is tandem mass spectrometry). These results demonstrate that deglycosylation increases absorption of dietary flavones in vivo and modulates inflammation by reducing TNF-α and NF-κB, suggesting the potential use of functional foods rich in flavones for the treatment and prevention of inflammatory diseases (Hostetler et al., 2012).

Colorectal Cancer

Association between the 6 main classes of flavonoids and the risk of colorectal cancer was examined using data from a national prospective case-control study in Scotland, including 1,456 incident cases and 1,456 population-based controls matched on age, sex, and residence area.

Dietary, including flavonoid, data were obtained from a validated, self-administered food frequency questionnaire. Risk of colorectal cancer was estimated using conditional logistic regression models in the whole sample and stratified by sex, smoking status, and cancer site and adjusted for established and putative risk factors.

The significant dose-dependent reductions in colorectal cancer risk that were associated with increased consumption of the flavonols quercetin, catechin, and epicatechin, remained robust after controlling for overall fruit and vegetable consumption or for other flavonoid intake. The risk reductions were greater among nonsmokers, but no interaction beyond a multiplicative effect was present.

This was the first of several a priori hypotheses to be tested in this large study and showed strong and linear inverse associations of flavonoids with colorectal cancer risk (Theodoratou et al., 2007).

Anti-angiogenic, Prostate Cancer

Luteolin is a common dietary flavonoid found in fruits and vegetables. The anti-angiogenic activity of luteolin was examined using in vitro, ex vivo, and in vivo models. Angiogenesis, the formation of new blood vessels from pre-existing vascular beds, is essential for tumor growth, invasion, and metastasis; hence, examination of this mechanism of tumor growth is essential to understanding new chemo-preventive targets. In vitro studies using rat aortic ring assay showed that luteolin at non-toxic concentrations significantly inhibited microvessel sprouting and proliferation, migration, invasion and tube formation of endothelial cells, which are key events in the process of angiogenesis. Luteolin also inhibited ex vivo angiogenesis as revealed by chicken egg chorioallantoic membrane assay (CAM) and matrigel plug assay.

Pro-inflammatory cytokines such as IL-1β, IL-6, IL-8, and TNF-α level were significantly reduced by the treatment of luteolin in PC-3 cells. Luteolin (10 mg/kg/d) significantly reduced the volume and the weight of solid tumors in prostate xenograft mouse model, indicating that luteolin inhibited tumorigenesis by targeting angiogenesis. Moreover, luteolin reduced cell viability and induced apoptosis in prostate cancer cells, which were correlated with the down-regulation of AKT, ERK, mTOR, P70S6K, MMP-2, and MMP-9 expressions.

Taken together, these findings demonstrate that luteolin inhibits human prostate tumor growth by suppressing vascular endothelial growth factor receptor 2-mediated angiogenesis (Pratheeshkumar et al., 2012).

Pancreatic Cancer; Chemo-sensitizer

The potential of dietary flavonoids apigenin (Api) and luteolin (Lut) were assessed in their ability to enhance the anti-proliferative effects of chemotherapeutic drugs on BxPC-3 human pancreatic cancer cells; additionally, the molecular mechanism of the action was probed.

Simultaneous treatment with either flavonoid (0,13, 25 or 50µM) and chemotherapeutic drugs 5-fluorouracil (5-FU, 50µM) or gemcitabine (Gem, 10µM) for 60 hours resulted in less-than-additive effect (p<0.05). Pre-treatment for 24 hours with 13µM of either Api or Lut, followed by Gem for 36 hours was optimal to inhibit cell proliferation. Pre-treatment of cells with 11-19µM of either flavonoid for 24 hours resulted in 59-73% growth inhibition when followed by Gem (10µM, 36h). Lut (15µM, 24h) pre-treatment followed by Gem (10µM, 36h), significantly decreased protein expression of nuclear GSK-3β and NF-κB p65 and increased pro-apoptotic cytosolic cytochrome c. Pre-treatment of human pancreatic cancer cells BxPC-3 with low concentrations of Api or Lut hence effectively aid in the anti-proliferative activity of chemotherapeutic drugs (Johnson et al., 2013).

Breast Cancer; Chemo-sensitizer, Tamoxifen

The oncogenic molecules in human breast cancer cells are inhibited by luteolin treatment and it was found that the level of cyclin E2 (CCNE2) mRNA was higher in tumor cells than in normal paired tissue samples as assessed using real-time reverse-transcriptase polymerase chain reaction (RT-PCR) analysis (n=257).

Combined treatment with 4-OH-TAM and luteolin synergistically sensitized the TAM-R cells to 4-OH-TAM. These results suggest that luteolin can be used as a chemo-sensitizer to target the expression level of CCNE2 and that it could be a novel strategy to overcome TAM resistance in breast cancer patients (Tu et al., 2013).

Breast Cancer

Consumers of higher levels of Brassica vegetables, particularly those of the genus Brassica (broccoli, Brussels sprouts and cabbage), reduce their susceptibility to cancer at a variety of organ sites. Brassica vegetables contain high concentrations of glucosinolates that can be hydrolyzed by the plant enzyme, myrosinase, or intestinal microflora to isothiocyanates, potent inducers of cytoprotective enzymes and inhibitors of carcinogenesis. Oral administration of either the isothiocyanate, sulforaphane, or its glucosinolate precursor, glucoraphanin, inhibits mammary carcinogenesis in rats treated with 7,12-dimethylbenz[a]anthracene. To determine whether sulforaphane exerts a direct chemo-preventive action on animal and human mammary tissue, the pharmacokinetics and pharmacodynamics of a single 150 µmol oral dose of sulforaphane were evaluated in the rat mammary gland.

Sulforaphane metabolites were detected at concentrations known to alter gene expression in cell culture. Elevated cytoprotective NAD(P)H:quinone oxidoreductase (NQO1) and heme oxygenase-1 (HO-1) gene transcripts were measured using quantitative real-time polymerase chain reaction. An observed 3-fold increase in NQO1 enzymatic activity, as well as 4-fold elevated immunostaining of HO-1 in rat mammary epithelium, provide strong evidence of a pronounced pharmacodynamic action of sulforaphane. In a subsequent pilot study, eight healthy women undergoing reduction mammoplasty were given a single dose of a broccoli sprout preparation containing 200 µmol of sulforaphane. Following oral dosing, sulforaphane metabolites were readily measurable in human breast tissue enriched for epithelial cells. These findings provide a strong rationale for evaluating the protective effects of a broccoli sprout preparation in clinical trials of women at risk for breast cancer (Cornblatt et al., 2007).

In a proof of principle clinical study, the presence of disseminated tumor cells (DTCs) was demonstrated in human breast tissue after a single dose of a broccoli sprout preparation containing 200 µmol of sulforaphane. Together, these studies demonstrate that sulforaphane distributes to the breast epithelial cells in vivo and exerts a pharmacodynamic action in these target cells consistent with its mechanism of chemo-protective efficacy.

Such efficacy, coupled with earlier randomized clinical trials revealing the safety of repeated doses of broccoli sprout preparations , supports further evaluation of broccoli sprouts in the chemoprevention of breast and other cancers (Cornblatt et al., 2007).

CSCs

Recent research into the effects of sulforaphane on cancer stem cells (CSCs) has drawn a great deal of interest. CSCs are suggested to be responsible for initiating and maintaining cancer, and to contribute to recurrence and drug resistance. A number of studies have indicated that sulforaphane may target CSCs in different types of cancer through modulation of NF- κB, SHH, epithelial-mesenchymal transition and Wnt/β-catenin pathways. Combination therapy with sulforaphane and chemotherapy in preclinical settings has shown promising results (Li et al., 2013).

Anti-inflammatory

Sulforaphane has been found to down-regulate COX-2 expression in human bladder transitional cancer T24 cells at both transcriptional- and translational levels. Cyclooxygenase-2 (COX-2) overexpression has been associated with the grade, prognosis and recurrence of transitional cell carcinoma (TCC) of the bladder. Sulforaphane (5-20 microM) induced nuclear translocation of NF-kappaB and reduced its binding to the COX-2 promoter, a key mechanism for suppressing COX-2 expression by sulforaphane. Moreover, sulforaphane increased expression of p38 and phosphorylated-p38 protein. Taken together, these data suggest that p38 is essential in sulforaphane-mediated COX-2 suppression and provide new insights into the molecular mechanisms of sulforaphane in the chemoprevention of bladder cancer (Shan et al., 2009).

Bladder Cancer

An aqueous extract of broccoli sprouts potently inhibits the growth of human bladder carcinoma cells in culture and this inhibition is almost exclusively due to the isothiocyanates. Isothiocyanates are present in broccoli sprouts as their glucosinolate precursors and blocking their conversion to isothiocyanates abolishes the anti-proliferative activity of the extract.

Moreover, the potency of isothiocyanates in the extract in inhibiting cancer cell growth was almost identical to that of synthetic sulforaphane, as judged by their IC50 values (6.6 versus 6.8 micromol/L), suggesting that other isothiocyanates in the extract may be biologically similar to sulforaphane and that nonisothiocyanate substances in the extract may not interfere with the anti-proliferative activity of the isothiocyanates. These data show that broccoli sprout isothiocyanate extract is a highly promising substance for cancer prevention/treatment and that its anti-proliferative activity is exclusively derived from isothiocyanates (Tang et al., 2006).

Ovarian Cancer

Sulforaphane is an extract from the mustard family recognized for its anti-oxidation abilities, phase 2 enzyme induction, and anti-tumor activity. The cell-cycle arrest in G2/M by sulforaphane and the expression of cyclin B1, Cdc2, and the cyclin B1/CDC2 complex in PA-1 cells using Western blotting and co-IP Western blotting. The anti-cancer effects of dietary isothiocyanate sulforaphane on ovarian cancer were investigated using cancer cells line PA-1.

Sulforaphane -treated cells accumulated in metaphase by CDC2 down-regulation and dissociation of the cyclin B1/CDC2 complex.

These findings suggest that, in addition to the known effects on cancer prevention, sulforaphane may also provide anti-tumor activity in established ovarian cancer (Chang et al., 2013).

Leukemia Stem Cells

Isolated leukemia stem cells (LSCs) showed high expression of Oct4, CD133, β-catenin, and Sox2 and imatinib (IM) resistance. Differentially, CD34(+)/CD38(-) LSCs demonstrated higher BCR-ABL and β-catenin expression and IM resistance than CD34(+)/CD38(+) counterparts. IM and sulforaphane (SFN) combined treatment sensitized CD34(+)/CD38(-) LSCs and induced apoptosis, shown by increased caspase 3, PARP, and Bax while decreased Bcl-2 expression. Mechanistically, imatinib (IM) and sulforaphane (SFN) combined treatment resensitized LSCs by inducing intracellular reactive oxygen species (ROS). Importantly, β-catenin-silenced LSCs exhibited reduced glutathione S-transferase pi 1 (GSTP1) expression and intracellular GSH level, which led to increased sensitivity toward IM and sulforaphane.

It was hence demonstrated that IM and sulforaphane combined treatment effectively eliminated CD34(+)/CD38(-) LSCs. Since SFN has been shown to be well tolerated in both animals and human, this regimen could be considered for clinical trials (Lin et al., 2012).

DCIS Stem Cells

A miR-140/ALDH1/SOX9 axis has been found to be critical to basal cancer stem cell self-renewal and tumor formation in vivo, suggesting that the miR-140 pathway may be a promising target for preventive strategies in patients with basal-like Ductal Carcinoma in Situ (DCIS). The dietary compound sulforaphane has been found to decrease Transcription factor SOX-9 and Acetaldehyde dehydrogenases (ALDH1), and thereby reduced tumor growth in vivo (Li et al., 2013).

Glioma, Prostate Cancer, Colon Cancer, Breast Cancer, Liver Cancer

Phenethyl isothiocyanate (PEITC), a natural dietary isothiocyanate, inhibits angiogenesis. The effects of PEITC were examined under hypoxic conditions on the intracellular level of the hypoxia inducible factor (HIF-1α) and extracellular level of the vascular endothelial growth factor (VEGF) in a variety of human cancer cell lines. Gupta et al., (2013) observed that PEITC suppressed the HIF-1α accumulation during hypoxia in human glioma U87, human prostate cancer DU145, colon cancer HCT116, liver cancer HepG2, and breast cancer SkBr3 cells. PEITC treatment also significantly reduced the hypoxia-induced secretion of VEGF.

Suppression of HIF-1α accumulation during treatment with PEITC in hypoxia was related to PI3K and MAPK pathways.

Taken together, these results suggest that PEITC inhibits the HIF-1α expression through inhibiting the PI3K and MAPK signaling pathway and provide a new insight into a potential mechanism of the anti-cancer properties of PEITC.

Breast Cancer Metastasis

Breast tumor metastasis is a leading cause of cancer-related deaths worldwide. Breast tumor cells frequently metastasize to brain and initiate severe therapeutic complications. The chances of brain metastasis are further elevated in patients with HER2 overexpression. The MDA-MB-231-BR (BR-brain seeking) breast tumor cells stably transfected with luciferase were injected into the left ventricle of mouse heart and the migration of cells to brain was monitored using a non-invasive IVIS bio-luminescent imaging system.

Results demonstrate that the growth of metastatic brain tumors in PEITC treated mice was about 50% less than that of control. According to Kaplan Meir's curve, median survival of tumor-bearing mice treated with PEITC was prolonged by 20.5%. Furthermore, as compared to controls, we observed reduced HER2, EGFR and VEGF expression in the brain sections of PEITC treated mice. These results demonstrate the anti-metastatic effects of PEITC in vivo in a novel breast tumor metastasis model and provides the rationale for further clinical investigation (Gupta et al., 2013).

Osteosarcoma, Melanoma

Phenethyl isothiocyanate (PEITC) has been found to induce apoptosis in human osteosarcoma U-2 OS cells. The following end points were determined in regard to human malignant melanoma cancer A375.S2 cells: cell morphological changes, cell-cycle arrest, DNA damage and fragmentation assays and morphological assessment of nuclear change, reactive oxygen species (ROS) and Ca2+ generations, mitochondrial membrane potential disruption, and nitric oxide and 10-N-nonyl acridine orange productions, expression and activation of caspase-3 and -9, B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax), Bcl-2, poly (adenosine diphosphate-ribose) polymerase, and cytochrome c release, apoptosis-inducing factor and endonuclease G. PEITC

It was therefore concluded that PEITC-triggered apoptotic death in A375.S2 cells occurs through ROS-mediated mitochondria-dependent pathways (Huang et al., 2013).

Prostate Cancer

The glucosinolate-derived phenethyl isothiocyanate (PEITC) has recently been demonstrated to reduce the risk of prostate cancer (PCa) and inhibit PCa cell growth. It has been shown that p300/CBP-associated factor (PCAF), a co-regulator for the androgen receptor (AR), is upregulated in PCa cells through suppression of the mir-17 gene. Using AR-responsive LNCaP cells, the inhibitory effects of PEITC were observed on the dihydrotestosterone-stimulated AR transcriptional activity and cell growth of PCa cells.

Expression of PCAF was upregulated in PCa cells through suppression of miR-17. PEITC treatment significantly decreased PCAF expression and promoted transcription of miR-17 in LNCaP cells. Functional inhibition of miR-17 attenuated the suppression of PCAF in cells treated by PEITC. Results indicate that PEITC inhibits AR-regulated transcriptional activity and cell growth of PCa cells through miR-17-mediated suppression of PCAF, suggesting a new mechanism by which PEITC modulates PCa cell growth (Yu et al., 2013).

Bladder Cancer; Adramycin (ADM) Resistance

The role of PEITC on ADM resistance reversal of human bladder carcinoma T24/ADM cells has been examined, including an increased drug sensitivity to ADM, cell apoptosis rates, intracellular accumulation of Rhodamine-123 (Rh-123), an increased expression of DNA topoisomerase II (Topo-II), and a decreased expression of multi-drug resistance gene (MDR1), multi-drug resistance-associated protein (MRP1), bcl-2 and glutathione s transferase π (GST-π). The results indicated that PEITC might be used as a potential therapeutic strategy to ADM resistance through blocking Akt and activating MAPK pathway in human bladder carcinoma (Tang et al., 2013).

Breast Cancer; Chemo-enhancing

The synergistic effect between paclitaxel (taxol) and phenethyl isothiocyanate (PEITC) on the inhibition of breast cancer cells has been examined. Two drug-resistant breast cancer cell lines, MCF7 and MDA-MB-231, were treated with PEITC and taxol. Cell growth, cell-cycle, and apoptosis were examined.

The combination of PEITC and taxol significantly decreased the IC50 of PEITC and taxol over each agent alone. The combination also increased apoptosis by more than 2-fold over each single agent in both cell lines. A significant increase of cells in the G2/M phases was detected. Taken together, these results indicated that the combination of PEITC and taxol exhibits a synergistic effect on growth inhibition in breast cancer cells. This combination deserves further study in vivo (Liu et al., 2013).

References

Chang CC, Hung CM, Yang YR, Lee MJ, Hsu YC. (2013). Sulforaphane induced cell-cycle arrest in the G2/M phase via the blockade of cyclin B1/CDC2 in human ovarian cancer cells. J Ovarian Res, 6(1):41. doi: 10.1186/1757-2215-6-41


Cornblatt BS, Ye LX, Dinkova-Kostova AT, et al. (2007). Preclinical and clinical evaluation of sulforaphane for chemoprevention in the breast. Carcinogenesis, 28(7):1485-1490. doi: 10.1093/carcin/bgm049


Gupta B, Chiang L, Chae K, Lee DH. (2013). Phenethyl isothiocyanate inhibits hypoxia-induced accumulation of HIF-1 α and VEGF expression in human glioma cells. Food Chem, 141(3):1841-6. doi: 10.1016/j.foodchem.2013.05.006.


Gupta P, Adkins C, Lockman P, Srivastava SK. (2013). Metastasis of Breast Tumor Cells to Brain Is Suppressed by Phenethyl Isothiocyanate in a Novel In Vivo Metastasis Model. PLoS One, 8(6):e67278. doi:10.1371/journal.pone.0067278


Hostetler G, Riedl K, Cardenas H, et al. (2012). Flavone deglycosylation increases their anti-inflammatory activity and absorption. Molecular Nutrition & Food Research, 56(4):558-569. doi: 10.1002/mnfr.201100596


Huang SH, Hsu MH, Hsu SC, et al. (2013). Phenethyl isothiocyanate triggers apoptosis in human malignant melanoma A375.S2 cells through reactive oxygen species and the mitochondria-dependent pathways. Hum Exp Toxicol. doi: 10.1177/0960327113491508


Johnson JL, Gonzalez de Mejia E. (2013). Interactions between dietary flavonoids apigenin or luteolin and chemotherapeutic drugs to potentiate anti-proliferative effect on human pancreatic cancer cells, in vitro. Food Chem Toxicol, 60:83-91. doi: 10.1016/j.fct.2013.07.036.


Li Q, Yao Y, Eades G, Liu Z, Zhang Y, Zhou Q. (2013). Down-regulation of miR-140 promotes cancer stem cell formation in basal-like early stage breast cancer. Oncogene. doi: 10.1038/onc.2013.226.


Li Y, Zhang T. (2013). Targeting cancer stem cells with sulforaphane, a dietary component from broccoli and broccoli sprouts. Future Oncol, 9(8):1097-103. doi: 10.2217/fon.13.108.


Lin LC, Yeh CT, Kuo CC, et al. (2012). Sulforaphane potentiates the efficacy of imatinib against chronic leukemia cancer stem cells through enhanced abrogation of Wnt/ β-catenin function. J Agric Food Chem, 60(28):7031-9. doi: 10.1021/jf301981n.


Liu K, Cang S, Ma Y, Chiao JW. (2013). Synergistic effect of paclitaxel and epigenetic agent phenethyl isothiocyanate on growth inhibition, cell-cycle arrest and apoptosis in breast cancer cells. Cancer Cell Int, 13(1):10. doi: 10.1186/1475-2867-13-10.


Pratheeshkumar P, Son YO, Budhraja A, et al. (2012). Luteolin inhibits human prostate tumor growth by suppressing vascular endothelial growth factor receptor 2-mediated angiogenesis. PLoS One, 7(12):52279. doi: 10.1371/journal.pone.0052279.


Tang K, Lin Y, Li LM. (2013). The role of phenethyl isothiocyanate on bladder cancer ADM resistance reversal and its molecular mechanism. Anat Rec (Hoboken), 296(6):899-906. doi: 10.1002/ar.22677.


Tang L, Zhang Y, Jobson HE, et al. (2006). Potent activation of mitochondria-mediated apoptosis and arrest in S and M phases of cancer cells by a broccoli sprout extract. Mol Cancer Ther, 5(4):935-44. doi: 10.1158/1535-7163.MCT-05-0476


Theodoratou E, Kyle J, Cetnarskyj R, et al. (2007). Dietary flavonoids and the risk of colorectal cancer. Cancer Epidemiol Biomarkers Prev,16(4):684-93.


Tu SH, Ho CT, Liu MF, et al. (2013). Luteolin sensitizes drug-resistant human breast cancer cells to tamoxifen via the inhibition of cyclin E2 expression. Food Chem, 141(2):1553-61. doi: 10.1016/j.foodchem.2013.04.077.


Shan Y, Wu K, Wang W, et al. (2009). Sulforaphane down-regulates COX-2 expression by activating p38 and inhibiting NF-kappaB-DNA-binding activity in human bladder T24 cells. Int J Oncol, 34(4):1129-34.


Yu C, Gong AY, Chen D, et al. (2013). Phenethyl isothiocyanate inhibits androgen receptor-regulated transcriptional activity in prostate cancer cells through suppressing PCAF. Mol Nutr Food Res. doi: 10.1002/mnfr.201200810.

Dehydrocostus (See also costunolide)

Cancers: Breast, cervical., lung, prostate, sarcoma

Action: Anti-metastatic, cytostatic, lymphangiogenesis inhibitors

Saussurea lappa has been used in Chinese traditional medicine for the treatment of abdominal pain, tenesmus, nausea, and cancer. Previous studies have shown that S. lappa also induces G2 growth arrest and apoptosis in gastric cancer cells.

Prostate Cancer

The effects of hexane extracts of S. lappa (HESLs) on the migration of DU145 and TRAMP-C2 prostate cancer cells were investigated. DU145 and TRAMP-C2 cells were cultured in the presence of 0-4 µg/mL HESL with or without 10 ng/mL epidermal growth factor (EGF).

The active compound, dehydrocostus lactone (DHCL), in fraction 7, dose-dependently inhibited the basal and EGF-induced migration of prostate cancer cells. HESL and DHCL reduced matrix metalloproteinase (MMP)-9 and tissue inhibitor of metalloproteinase (TIMP)-1 secretion but increased TIMP-2 levels in both the absence and presence of EGF.

Results demonstrated that the inhibition of MMP-9 secretion, and the stimulation of TIMP-2 secretion, contribute to reduced migration of DU145 cells treated with HESL and DHCL. This indicates that HESL containing its active principle, DHCL, has potential as an anti-metastatic agent in the treatment of prostate cancer (Kim et al., 2012).

Sarcoma

Human soft tissue sarcomas represent a rare group of malignant tumors that frequently exhibit chemotherapeutic resistance and increased metastatic potential following unsuccessful treatment. The effects of the costunolide and dehydrocostus lactone, which have been isolated from Saussurea lappa using activity-guided isolation, were studied on three soft tissue sarcoma cell lines of various origins. The effects on cell proliferation, cell-cycle distribution, apoptosis induction, and ABC transporter expression were analyzed. Both compounds inhibited cell viability dose- and time-dependently.

IC50 values ranged from 6.2 µg/mL to 9.8 µg/mL. Cells treated with costunolide showed no changes in cell-cycle, little in caspase 3/7 activity, and low levels of cleaved caspase-3 after 24 and 48 hours. Dehydrocostus lactone caused a significant reduction of cells in the G1 phase and an increase of cells in the S and G2/M phase.

These data demonstrate for the first time that dehydrocostus lactone affects cell viability, cell-cycle distribution and ABC transporter expression in soft tissue sarcoma cell lines. Furthermore, it led to caspase 3/7 activity as well as caspase-3 and PARP cleavage, which are indicators of apoptosis. Therefore, this compound may be a promising lead candidate for the development of therapeutic agents against drug-resistant tumors (Kretschmer et al., 2012).

The effects of the sesquiterpene lactones, costunolide and dehydrocostus, on the cell-cycle, MMP expression, and invasive potential of three human STS cell lines of various origins. Both compounds reduced cell proliferation in a time- and dose-dependent manner.

Dehydrocostus lactone significantly inhibited cell proliferation, arrested the cells at the G2/M interface and caused a decrease in the expression of the cyclin-dependent kinase CDK2 and the cyclin-dependent kinase inhibitor p27 (Kip1).

In the presence of costunolide, MMP-2 and MMP-9 levels were significantly increased in SW-982 and TE-671 cells. Dehydrocostus lactone treatment significantly reduced MMP-2 and MMP-9 expression in TE-671 cells, but increased MMP-9 level in SW-982 cells. In addition, the invasion potential was significantly reduced after treatment with both sesquiterpene lactones as investigated by the HTS FluoroBlock insert system (Lohberger et al., 2013).

Breast Cancer

Several Chinese herbs, namely, pu gong ying (Taraxacum officinale), gan cao (Glycyrrhizae uralensis), chai hu (Bupleurum chinense), mu xiang (Auklandia lappa), gua lou (Trichosanthes kirilowii) and huang yao zi (Dioscoreae bulbiferae), are frequently used in complex traditional Chinese medicine formulas, for breast hyperplasia and breast tumor therapy. The effects of these Chinese herbs are all described as 'clearing heat-toxin and resolving masses' in traditional use. However, the chemical profiles of anti-breast cancer constituents in these herbs have not been investigated thus far.

Two potential anti-breast cancer compounds, costunolide (Cos) and dehydrocostus lactone (Dehy), were identified in mu xiang. The combination of the two compounds showed a synergistic effect on inhibiting the proliferation of MCF-7 cells in vitro, exhibiting potential application in the treatment of breast cancer (Peng, Wang, Gu, Wen & Yan, 2013).

Lymphangiogenesis Inhibitors

In this study, we investigated lymphangiogenesis inhibitors from crude drugs used in Japan and Korea. The three crude drugs Saussureae Radix, Psoraleae Semen and Aurantti Fructus Immaturus significantly inhibited the proliferation of temperature-sensitive rat lymphatic endothelial (TR-LE) cells in vitro. These compounds might offer clinical benefits as lymphangiogenesis inhibitors and may be good candidates for novel anti-cancer and anti-metastatic agents (Jeong, 2013).

References

Jeong D, Watari K, Shirouzu T, et al. (2013). Studies on lymphangiogenesis inhibitors from Korean and Japanese crude drugs. Biological & Pharmaceutical Bulletin, 36(1), 152-7.


Kim EJ, Hong JE, Lim SS, et al. (2012). The hexane extract of Saussurea lappa and its active principle, dehydrocostus lactone, inhibit prostate cancer cell migration. Journal of Medicinal Food, 15(1), 24-32. doi: 10.1089/jmf.2011.1735.


Kretschmer N, Rinner B, Stuendl N, et al. (2012). Effect of costunolide and dehydrocostus lactone on cell-cycle, apoptosis, and ABC transporter expression in human soft tissue sarcoma cells. Planta Medica, 78(16), 1749-1756. doi: 10.1055/s-0032-1315385.


Lohberger B, Rinner B, Stuendl N, et al. (2013). Sesquiterpene lactones downregulate g2/m cell-cycle regulator proteins and affect the invasive potential of human soft tissue sarcoma cells. PLoS One, 8(6), e66300. doi: 10.1371/journal.pone.0066300.


Peng ZX, Wang Y, Gu X, Wen YY, Yan C. (2013). A platform for fast screening potential anti-breast cancer compounds in traditional Chinese medicines. Biomedical Chromatography. doi: 10.1002/bmc.2990.

Dauricine

Cancer: Prostate, urinary system, breast, lung

Action: MDR

Lung Cancer

Menispermum dauricum DC (Moonseed) contains several alkaloids, of which dauricine can account for as much as 50% of the alkaloids present. In human lung adenocarcinoma A549 cells, these alkaloids activate caspase-3 by activating caspases-8 and -9. Accordingly, these alkaloids induce apoptosis through the apoptosis death receptor and mitochondrial pathways (Wang et al., 2011).

Prostate Cancer

The anti-tumor effects of asiatic moonseed rhizome extraction-dauricine were explored on bladder cancer EJ cell strain, prostate cancer PC-3Mcell strain and primary cell culture system. The main effective component, phenolic alkaloids of Menispermum dauricum, was extracted and separated from asiatic moonseed rhizome by chemical method.

Dauricine had an obvious proliferation inhibition effect on the main tumor cells in urinary system. The minimum drug sensitivity concentration was between 3.81-5.15 µg/mL, and the inhibition ratio increased with the increased concentration. Dauricine, the main effective component extracted from asiatic moonseed rhizome, had good inhibition effect on tumor cells in the urinary system. At the same time, Dauricine has certain inhibition effects on the primary cultured tumor cell (Wang et al., 2012).

Breast Cancer

Serum-starved MCF-7 cells were pretreated for 1 h with different concentrations of dauricine (Dau), followed by incubation with IGF-I for 6 h. Dau significantly inhibited IGF-I-induced HIF-1alpha protein expression but had no effect on HIF-1alpha mRNA expression. However, Dau remarkably suppressed VEGF expression at both protein and mRNA levels in response to IGF-I. Mechanistically, Dau suppressed IGF-I-induced HIF-1alpha and VEGF protein expression mainly by blocking the activation of PI-3K/AKT/mTOR signaling pathway.

Dau inhibits human breast cancer angiogenesis by suppressing HIF-1alpha protein accumulation and VEGF expression, which may provide a novel potential mechanism for the anti-cancer activities of Dau in human breast cancer (Tang et al., 2009).

Breast Cancer; MDR

The potentiation of vincristine-induced apoptosis by tetrandrine, neferine and dauricine isolated from Chinese medicinal plants in the human mammary MCF-7 Multi-drug-resistant cells was investigated. The apoptotic cells induced by vincristine alone accounted for about 10% of all the cancer cells, while the percentage of apoptotic cells induced by a combination of vincristine with tetrandrine, neferine, or dauricine was found to be significantly higher than that by vincristine alone, and their reversal effects were positively correlated with the drug concentration and the exposure time.

In addition, tetrandrine was shown to be the most potent in the reversal efficacy among the three compounds to be tested for apoptosis in vitro. Tetrandrine, neferine and dauricine showed obvious potentiation of vincristine-induced apoptosis in the human mammary MCF-7 multi-drug-resistant cells (Ye et al., 2001).

MDR

Bisbenzylisoquinoline alkaloids are a large family of natural phytochemicals with great potential for clinical use. The interaction between breast cancer resistant protein (BCRP), sometimes called ATP binding cassette protein G2 (ABCG2), and 5 bisbenzylisoquinoline alkaloids (neferine, isoliensinine, liensinine, dauricine and tetrandrine) was evaluated using LLC-PK1/BCRP cell model.

The intracellular accumulation and bi-directional transport studies were conducted, and then molecular docking analysis was carried out employing a homology model of BCRP. This data indicates that BCRP could mediate the excretion of liensinine and dauricine, and thus influence their pharmacological activity and disposition (Tian et al., 2013).

References

Tang XD, Zhou X, Zhou KY. (2009). Dauricine inhibits insulin-like growth factor-I-induced hypoxia inducible factor 1alpha protein accumulation and vascular endothelial growth factor expression in human breast cancer cells. Acta Pharmacol Sin, 30(5):605-16. doi: 10.1038/aps.2009.8.

Tian Y, Qian S, Jiang Y, et al. (2013). The interaction between human breast cancer resistance protein (BCRP) and five bisbenzylisoquinoline alkaloids. Int J Pharm, 453(2):371-9. doi: 10.1016/j.ijpharm.2013.05.053.

Wang J, Li Y, Zu XB, Chen MF, Qi L. (2012). Dauricine can inhibit the activity of proliferation of urinary tract tumor cells. Asian Pac J Trop Med, 5(12):973-6. doi: 10.1016/S1995-7645(12)60185-0.

Wang YG, Sun S, Yang WS, Sun FD, Liu Q. (2011). Extract of Menispermum Dauricum induces apoptosis of human lung cancer cell line A549. J Pract Oncol (Chin), 26:343-346.

Ye ZG, Wang JH, Sun AX, et al. (2001). Potentiation of vincristine-induced apoptosis by tetrandrine, neferine and dauricine in the human mammary MCF-7 Multi-drug-resistant cells. Yao Xue Xue Bao, 36(2):96-9.

Dandelion Root Extract (Taraxacum)

Cancer:
Pancreatic, Chronic Myelomonocytic Leukemia, leukemia, liver, hepatocellular carcinoma

Action: Induces cytotoxicity, induces apoptosis

Dandelion root is extracted from Taraxacum officinale (F.H. Wigg).

Hepatocellular Carcinoma

Taraxacum officinale (TO) has been frequently used as a remedy for women's diseases (e.g. breast and uterus cancer) and disorders of the liver and gallbladder. Several earlier studies have indicated that TO exhibits anti-tumor properties. TO decreased the cell viability by 26%, and significantly increased the tumor necrosis factor (TNF)-alpha and interleukin (IL)-1alpha production compared with media control (about 1.6-fold for TNF-alpha, and 2.4-fold for IL-1alpha, P < 0.05). Also, TO strongly induced apoptosis of Hep G2 cells as determined by flow cytometry. Increased amounts of TNF-alpha and IL-1alpha contributed to TO-induced apoptosis. Anti-TNF-alpha and IL-1alpha antibodies almost abolished it. These results suggest that TO induces cytotoxicity through TNF-alpha and IL-1alpha secretion in Hep G2 cells (Koo et al., 2004).

Pancreatic Cancer

The efficacy of dandelion root extract (DRE) in inducing apoptosis and autophagy in aggressive and resistant pancreatic cancer cells, known to have a high rate of mortality, have been investigated. The effect of DRE was evaluated using WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate) assay.

This extract induces selective apoptosis in a dose- and time-dependent manner. Dandelion root extract caused the collapse of the mitochondrial membrane potential., leading to prodeath autophagy. Normal human fibroblasts were resistant at similar doses. It was demonstrated that DRE has the potential to induce apoptosis and autophagy in human pancreatic cancer cells with no significant effect on noncancerous cells. This will provide a basis on which further research in cancer treatment through DRE can be executed (Ovadje et al., 2012a).

Chronic Myelomonocytic Leukemia

Chronic myelomonocytic leukemia (CMML) is a heterogeneous disease that is not only hard to diagnose and classify, but is also highly resistant to treatment. Available forms of therapy for this disease have not shown significant effects and patients rapidly develop resistance early on in therapy. These factors lead to the very poor prognosis observed with CMML patients, with median survival duration between 12 and 24 months after diagnosis. This study is therefore centered around evaluating the selective efficacy of a natural extract from dandelion roots, in inducing programmed cell death in aggressive and resistant CMML cell lines.

The results from this study indicate that Dandelion Root Extract (DRE) is able to efficiently and selectively induce apoptosis and autophagy in these cell lines in a dose and time-dependent manner, with no significant toxicity on non-cancerous peripheral blood mononuclear cells. More importantly, we observed early activation of initiator caspase-8, which led to mitochondrial destabilization and the induction of autophagy, suggesting that DRE acts through the extrinsic pathway of apoptosis (Ovadje et al., 2012b).

Leukemia

A study by Ovadje et al. (2011) determined the anti-cancer activity of dandelion root extract (DRE) against human leukemia, and evaluated the specificity and mechanism of DRE-induced apoptosis. Aqueous DRE contains components that act to induce apoptosis selectively in cultured leukemia cells, emphasizing the importance of this traditional medicine and thus presents a potential novel non-toxic alternative to conventional leukemia therapy.

References

Koo HN, Hong SH, Song BK, et al. (2004). Taraxacum officinale induces cytotoxicity through TNF-alpha and IL-1alpha secretion in Hep G2 cells. Life Sci, 74(9):1149-57.


Ovadje P, Chatterjee S, Griffin C, et al. (2011). Selective induction of apoptosis through activation of caspase-8 in human leukemia cells (Jurkat) by dandelion root extract. J Ethnopharmacol, 133(1):86-91. doi: 10.1016/j.jep.2010.09.005.


Ovadje P, Chochkeh M, Akbari-Asl P, Hamm C, Pandey S. (2012). Selective Induction of Apoptosis and Autophagy Through Treatment With Dandelion Root Extract in Human Pancreatic Cancer Cells. Pancreas, 41(7),1039-47. doi: 10.1097/MPA.0b013e31824b22a2.


Ovadje P, Hamm C, Pandey S. b (2012). Efficient induction of extrinsic cell death by dandelion root extract in human chronic myelomonocytic leukemia (CMML) cells. PLoS One. 2012;7(2):e30604. doi: 10.1371/journal.pone.0030604.