Category Archives: iNOS

A549, Akt, angiogenesis, Anti-angiogenic, Anti-cancer, Anti-estrogenic, anti-inflammatory, anti-lymphangiogenesis, anti-metastasis, Anti-metastatic, anti-tumor, anti-tumor activity, apoptosis, apoptosis-inducing, Apoptotic, BAX, Bcl-2, Breast cancer, c-ErbB2, CAM, CD31, cell-cycle arrest, Cervical cancer, Chapter 7 Isolates and Cancer Research, chemo-preventive, Chemo-preventive agent, Chemo-protective, Chemo-sensitizer, Chemotherapy, Colon Cancer or Colorectal cancer, COX-2, ER, ER-negative, ER-positive, ERK1, G1, GBC-SD, HCT116, HeLa, Hep G2,Hep 3B and SK-Hep1, HIF, HT-29, hypoxia-induced drug resistance, IGF-1, IL-1, iNOS, LM8, Lung cancer, MCF-7, MCP-1, MDR, metastasis, Multi-Drug Resistance, Multi-drug resistance, neuro-protective, Osteosarcoma, p-Akt, p27, p53, PARP, PGE2, PI3K, PI3K/Akt, Pro-apoptotic, pro-oxidative, ROS, Sarcoma, T47D, MDA-MB-231, TNF, TRAIL, VEGF, VEGF, VEGFR

Wogonin

Cancer:
Breast, lung (NSCLC), gallbladder carcinoma, osteosarcoma, colon, cervical

Action: Neuro-protective, anti-lymphangiogenesis, anti-angiogenic, anti-estrogenic, chemo-sensitizer, pro-oxidative, hypoxia-induced drug resistance, anti-metastatic, anti-tumor, anti-inflammatory

Wogonin is a plant monoflavonoid isolated from Scutellaria rivularis (Benth.) and Scutellaria baicalensis (Georgi).

Breast Cancer; ER+ & ER-

Effects of wogonin were examined in estrogen receptor (ER)-positive and -negative human breast cancer cells in culture for proliferation, cell-cycle progression, and apoptosis. Cell growth was attenuated by wogonin (50-200 microM), independently of its ER status, in a time- and concentration-dependent manner. Apoptosis was enhanced and accompanied by up-regulation of PARP and Caspase 3 cleavages as well as pro-apoptotic Bax protein. Akt activity was suppressed and reduced phosphorylation of its substrates, GSK-3beta and p27, was observed. Suppression of Cyclin D1 expression suggested the down-regulation of the Akt-mediated canonical Wnt signaling pathway.

ER expression was down-regulated in ER-positive cells, while c-ErbB2 expression and its activity were suppressed in ER-negative SK-BR-3 cells. Wogonin feeding to mice showed inhibition of tumor growth of T47D and MDA-MB-231 xenografts by up to 88% without any toxicity after 4 weeks of treatment. As wogonin was effective both in vitro and in vivo, our novel findings open the possibility of wogonin as an effective therapeutic and/or chemo-preventive agent against both ER-positive and -negative breast cancers, particularly against the more aggressive and hormonal therapy-resistant ER-negative types (Chung et al., 2008).

Neurotransmitter Action

Kim et al. (2011) found that baicalein and wogonin activated the TREK-2 current by increasing the opening frequency (channel activity: from 0.05 ± 0.01 to 0.17 ± 0.06 in baicalein treatment and from 0.03 ± 0.01 to 0.29 ± 0.09 in wogonin treatment), while leaving the single-channel conductance and mean open time unchanged. Baicalein continuously activated TREK-2, whereas wogonin transiently activated TREK-2. Application of baicalein and wogonin activated TREK-2 in both cell attached and excised patches, suggesting that baicalein and wogonin may modulate TREK-2 either directly or indirectly with different mechanisms. These results suggest that baicalein- and wogonin-induced TREK-2 activation help set the resting membrane potential of cells exposed to pathological conditions and thus may give beneficial effects in neuroprotection.

Anti-metastasic

The migration and invasion assay was used to evaluate the anti-metastasis effect of wogonin. Wogonin at the dose of 1–10 µM, which did not induce apoptosis, significantly inhibited the mobility and invasion activity of human gallbladder carcinoma GBC-SD cells. In addition, the expressions of matrix metalloproteinase (MMP)-2, MMP-9 and phosphorylated extracellular regulated protein kinase 1/2 (ERK1/2) but not phosphorylated Akt were dramatically suppressed by wogonin in a concentration-dependent manner. Furthermore, the metastasis suppressor maspin was confirmed as the downstream target of wogonin.

These findings suggest that wogonin inhibits cell mobility and invasion by up-regulating the metastasis suppressor maspin. Together, these data provide novel insights into the chemo-protective effect of wogonin, a main active ingredient of Chinese medicine Scutellaria baicalensis (Dong et al., 2011).

Anti-tumor and Anti-metastatic

Kimura & Sumiyoshi (2012) examined the effects of wogonin isolated from Scutellaria baicalensis roots on tumor growth and metastasis using a highly metastatic model in osteosarcoma LM8-bearing mice. Wogonin (25 and 50mg/kg, twice daily) reduced tumor growth and metastasis to the lung, liver and kidney, angiogenesis (CD31-positive cells), lymphangiogenesis (LYVE-1-positive cells), and TAM (F4/80-positive cell) numbers in the tumors of LM8-bearing mice. Wogonin (10–100µM) also inhibited increases in IL-1β production and cyclooxygenase (COX)-2 expression induced by lipopolysaccharide in THP-1 macrophages. The anti-tumor and anti-metastatic actions of wogonin may be associated with the inhibition of VEGF-C-induced lymphangiogenesis through a reduction in VEGF-C-induced VEGFR-3 phosphorylation by the inhibition of COX-2 expression and IL-1β production in Tumor-associated macrophages (TAMs).

Anti-inflammatory

Wogonin extracted from Scutellariae baicalensis and S. barbata is a cell-permeable and orally available flavonoid that displays anti-inflammatory properties. Wogonin is reported to suppress the release of NO by iNOS, PGE2 by COX-2, pro-inflammatory cytokines, and MCP-1 gene expression and NF-kB activation (Chen et al., 2008).

Hypoxia-Induced Drug Resistance (MDR)

Hypoxia-induced drug resistance is a major obstacle in the development of effective cancer therapy. The reversal abilities of wogonin on   hypoxia resistance were examined and the underlying mechanisms discovered. MTT assay revealed that hypoxia increased maximal 1.71-, 2.08-, and 2.15-fold of IC50 toward paclitaxel, ADM, and DDP in human colon cancer cell lines HCT116, respectively. Furthermore, wogonin showed strong reversal potency in HCT116 cells in hypoxia and the RF reached 2.05. Hypoxia-inducible factor-1α (HIF-1α) can activate the expression of target genes involved in glycolysis. Wogonin decreased the expression of glycolysis-related proteins (HKII, PDHK1, LDHA), glucose uptake, and lactate generation in a dose-dependent manner.

In summary, wogonin could be a good candidate for the development of a new multi-drug resistance (MDR) reversal agent and its reversal mechanism probably is due to the suppression of HIF-1α expression via inhibiting PI3K/Akt signaling pathway (Wang et al., 2013).

NSCLC

Wogonin, a flavonoid originated from Scutellaria baicalensis Georgi, has been shown to enhance TRAIL-induced apoptosis in malignant cells in in vitro studies. In this study, the effect of a combination of TRAIL and wogonin was tested in a non-small-cell lung cancer xenografted tumor model in nude mice. Consistent with the in vitro study showing that wogonin sensitized A549 cells to TRAIL-induced apoptosis, wogonin greatly enhanced TRAIL-induced suppression of tumor growth, accompanied with increased apoptosis in tumor tissues as determined by TUNEL assay.

The down-regulation of these antiapoptotic proteins was likely mediated by proteasomal degradation that involved intracellular reactive oxygen species (ROS), because wogonin robustly induced ROS accumulation and ROS scavengers butylated hydroxyanisole (BHA) and N-acetyl-L-cysteine (NAC) and the proteasome inhibitor MG132 restored the expression of these antiapoptotic proteins in cells co-treated with wogonin and TRAIL.

These results show for the first time that wogonin enhances TRAIL's anti-tumor activity in vivo, suggesting this strategy has an application potential for clinical anti-cancer therapy (Yang et al., 2013).

Colon Cancer

Following treatment with baicalein or wogonin, several apoptotic events were observed, including DNA fragmentation, chromatin condensation and increased cell-cycle arrest in the G1 phase. Baicalein and wogonin decreased Bcl-2 expression, whereas the expression of Bax was increased in a dose-dependent manner compared with the control. Furthermore, the induction of apoptosis was accompanied by an inactivation of phosphatidylinositol 3-kinase (PI3K)/Akt in a dose-dependent manner.

The administration of baicalein to mice resulted in the inhibition of the growth of HT-29 xenografts without any toxicity following 5 weeks of treatment. The results indicated that baicalein induced apoptosis via Akt activation in a p53-dependent manner in the HT-29 colon cancer cells and that it may serve as a chemo-preventive or therapeutic agent for HT-29 colon cancer (Kim et al., 2012).

Breast

The involvement of insulin-like growth factor-1 (IGF-1) and estrogen receptor α (ERα) in the inhibitory effect of wogonin on the breast adenocarcinoma growth was determined. Moreover, the effect of wogonin on the angiogenesis of chick chorioallantoic membrane (CAM) was also investigated. The results showed wogonin and ICI182780 both exhibited a potent ability to blunt IGF-1-stimulated MCF-7 cell growth. Either of wogonin and ICI182780 significantly inhibited ERα and p-Akt expressions in IGF-1-treated cells. The inhibitory effect of wogonin showed no difference from that of ICI182780 on IGF-1-stimulated expressions of ERα and p-Akt. Meanwhile, wogonin at different concentrations showed significant inhibitory effect on CAM angiogenesis.

These results suggest the inhibitory effect of wogonin on breast adenocarcinoma growth via inhibiting IGF-1-mediated PI3K-Akt pathway and regulating ERα expression. Furthermore, wogonin has a strong anti-angiogenic effect on CAM model (Ma et al., 2012).

Chemoresistance; Cervical Cancer, NSCLC

Chemoresistance to cisplatin is a major limitation of cisplatin-based chemotherapy in the clinic. The combination of cisplatin with other agents has been recognized as a promising strategy to overcome cisplatin resistance. Previous studies have shown that wogonin (5,7-dihydroxy-8-methoxyflavone), a flavonoid isolated from the root of the medicinal herb Scutellaria baicalensis Georgi, sensitizes cancer cells to chemotheraputics such as etoposide, adriamycin, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and TNF.

In this study, the non-small-cell lung cancer cell line A549 and the cervical cancer cell line HeLa were treated with wogonin or cisplatin individually or in combination. It was found for the first time that wogonin is able to sensitize cisplatin-induced apoptosis in both A549 cells and HeLa cells as indicated by the potentiation of activation of caspase-3, and cleavage of the caspase-3 substrate PARP in wogonin and cisplatin co-treated cells.

Results provided important new evidence supporting the potential use of wogonin as a cisplatin sensitizer for cancer therapy (He et al., 2012).

References

Chen LG, Hung LY, Tsai KW, et al. (2008). Wogonin, a bioactive flavonoid in herbal tea, inhibits inflammatory cyclooxygenase-2 gene expression in human lung epithelial cancer cells. Mol Nutr Food Res. 52:1349-1357.


Chung H, Jung YM, Shin DH, et al. (2008). Anti-cancer effects of wogonin in both estrogen receptor-positive and -negative human breast cancer cell lines in vitro and in nude mice xenografts. Int J Cancer, 122(4):816-22.


Dong P, Zhang Y, Gu J, et al. (2011). Wogonin, an active ingredient of Chinese herb medicine Scutellaria baicalensis, inhibits the mobility and invasion of human gallbladder carcinoma GBC-SD cells by inducing the expression of maspin. J Ethnopharmacol, 137(3):1373-80. doi: 10.1016/j.jep.2011.08.005.


He F, Wang Q, Zheng XL, et al. (2012). Wogonin potentiates cisplatin-induced cancer cell apoptosis through accumulation of intracellular reactive oxygen species. Oncology Reports, 28(2), 601-605. doi: 10.3892/or.2012.1841.


Kim EJ, Kang D, Han J. (2011). Baicalein and wogonin are activators of rat TREK-2 two-pore domain K+ channel. Acta Physiologica, 202(2):185–192. doi: 10.1111/j.1748-1716.2011.02263.x.


Kim SJ, Kim HJ, Kim HR, et al. (2012). Anti-tumor actions of baicalein and wogonin in HT-29 human colorectal cancer cells. Mol Med Rep, 6(6):1443-9. doi: 10.3892/mmr.2012.1085.


Kimura Y & Sumiyoshi M. (2012). Anti-tumor and anti-metastatic actions of wogonin isolated from Scutellaria baicalensis roots through anti-lymphangiogenesis. Phytomedicine, 20(3-4):328-336. doi:10.1016/j.phymed.2012.10.016


Ma X, Xie KP, Shang F, et al. (2012). Wogonin inhibits IGF-1-stimulated cell growth and estrogen receptor α expression in breast adenocarcinoma cell and angiogenesis of chick chorioallantoic membrane. Sheng Li Xue Bao, 64(2):207-12.


Wang H, Zhao L, Zhu LT, et al. (2013). Wogonin reverses hypoxia resistance of human colon cancer HCT116 cells via down-regulation of HIF-1α and glycolysis, by inhibiting PI3K/Akt signaling pathway. Mol Carcinog. doi: 10.1002/mc.22052.


Yang L, Wang Q, Li D, et al. (2013). Wogonin enhances anti-tumor activity of tumor necrosis factor-related apoptosis-inducing ligand in vivo through ROS-mediated down-regulation of cFLIPL and IAP proteins. Apoptosis, 18(5):618-26. doi: 10.1007/s10495-013-0808-8.

A549, Akt, angiogenesis, Anti-angiogenic, Anti-cancer, anti-inflammatory, Anti-metastatic, anti-tubulin, apoptosis, bFGF, Breast cancer, c-Jun, cell-cycle arrest, Chapter 7 Isolates and Cancer Research, chemo-prevention, Chemotherapy, Colon Cancer or Colorectal cancer, COX-2, Cytostatic, cytotoxic, Dendrobrium loddigesii, ERK1, G1, G2/M, HCT-116, HIF, induces apoptosis, inflammation, iNOS, JNK, Lung cancer, MDA-MB-231, metastasis, Rectal cancer, ROS, Twist, VEGF, VEGF

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.

Akt, angiogenesis, Anti-cancer, Anti-cancer effect, anti-inflammatory, anti-oxidant, anti-proliferative, AP-1, apoptosis, apoptosis-inducing, Apoptotic, Bcl-xL, Breast cancer, CCNE2, CDK2, CDK4, cell-cycle arrest, Chapter 8 Injectables and Cancer Research, chemo-preventive, Chemo-sensitizer, Chemotherapy, Colon Cancer or Colorectal cancer, COX-2, CSCs, EpCAM, G2/M, hepato-protective, IL-6, Immunomodulatory, including Terminalia chebula, inflammation, inhibits VEGF, iNOS, JNK, Lung cancer, Mcl-1, metastasis, Nitric Oxide, Ovarian cancer, p53, p65, Pancreatic cancer, PGE2, Pro-apoptotic, Radio-protective, TAM chemo-sensitizer, TAM resistance, TNF, TRAIL, VEGF, VEGF

Luteolin

Cancer: Colorectal., pancreatic, ovarian, breast

Action: Anti-inflammatory, radio-protective, TAM chemo-sensitizer

Luteolin is a flavonoid found in many plants and foods, including Terminalia chebula (Retz.), Prunella vulgaris (L.) and Perilla frutescens [(L.) Britton].

Luteolin is contained in Ocimum sanctum L. or Ocimum tenuiflorum L, commonly known as Holy Basil in English or Tulsi in various Indian languages; it is an important medicinal plant in the various traditional and folk systems of medicine in Southeast Asia. Scientific studies have shown it to possess anti-inflammatory, anti-analgesic, anti-pyretic, anti-diabetic, hepato-protective, hypolipidemic, anti-stress, and immunomodulatory activities. It has been found to prevent chemical-induced skin, liver, oral., and lung cancers and mediates these effects by increasing the anti-oxidant activity, altering the gene expressions, inducing apoptosis, and inhibiting angiogenesis and metastasis.

Radio-protective

The aqueous extract of Tulsi has been shown to protect mice against γ-radiation-induced sickness and mortality and to selectively protect the normal tissues against the tumoricidal effects of radiation. The chemo-preventive and radio-protective properties of Tulsi emphasize aspects that warrant future research to establish its activity and utility in cancer prevention and treatment (Baliga et al., 2013).

Anti-inflammatory

Pre-treatment of RAW 264.7 with luteolin, luteolin-7-glucoside, quercetin, and the isoflavonoid genistein inhibited both the LPS-stimulated TNF-αand interleukin-6 release, whereas eriodictyol and hesperetin only inhibited TNF-αrelease. From the compounds tested luteolin and quercetin were the most potent in inhibiting cytokine production with an IC50 of less than 1 and 5 µM for TNF-αrelease, respectively. Pre-treatment of the cells with luteolin attenuated LPS-induced tyrosine phosphorylation of many discrete proteins. Luteolin inhibited LPS-induced phosphorylation of Akt. Treatment of macrophages with LPS resulted in increased IκB-αphosphorylation and reduced the levels of IκB-α. It was concluded that luteolin inhibits protein tyrosine phosphorylation, nuclear factor-κB-mediated gene expression and pro-inflammatory cytokine production in murine macrophages (Xagorari et al., 2001).

Luteolin (Lut) possesses significant anti-inflammatory activity in well established models of acute and chronic inflammation, such as xylene-induced ear edema in mice (ED50= 107 mg/ kg), carrageenin-induced swellingof the ankle, acetic acid-induced pleurisy and croton oil-induced gaseous pouch granuloma in rats. Its combined immunostimulatory and anti-inflammatory activity, and inhibitory effect upon immediate hypersensitive response provide the pharmacologic bases for the beneficial effects of Lut in the treatment of chronic bronchitis (Chen et al., 1986).

Anti-inflammatory; Lung

Luteolin dose-dependently inhibited the expression and production of nitric oxide (NO) and prostaglandin E2 (PGE2), as well as the expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). Luteolin also reduced the DNA binding activity of nuclear factor-kappa B (NF-κB) in LPS-activated macrophages. Moreover, luteolin blocked the degradation of IκB-α and nuclear translocation of NF-κB p65 subunit.

In sum, these data suggest that, by blocking NF-κ>B and AP-1 activation, luteolin acts to suppress the LPS-elicited inflammatory events in mouse alveolar macrophages, and this effect was mediated, at least in part, by inhibiting the generation of reactive oxygen species. These observations suggest a possible therapeutic application of this agent for treating inflammatory disorders in the lung (Chen et al., 2007).

Anti-inflammatory; Neuroinflammation

Pre-treatment of primary murine microglia and BV-2 microglial cells with luteolin inhibited LPS-stimulated IL-6 production at both the mRNA and protein levels. Whereas luteolin had no effect on the LPS-induced increase in NF-κB DNA binding activity, it markedly reduced AP-1 transcription factor binding activity. To determine whether luteolin might have similar effects in vivo, mice were provided drinking water supplemented with luteolin for 21 days and then they were injected i.p. with LPS. Luteolin consumption reduced LPS-induced IL-6 in plasma 4 hours after injection. Taken together, these data suggest luteolin inhibits LPS-induced IL-6 production in the brain by inhibiting the JNK signaling pathway and activation of AP-1 in microglia. Thus, luteolin may be useful for mitigating neuroinflammation (Jang et al., 2008).

Colon Cancer

Activities of CDK4 and CDK2 decreased within 2 hours after luteolin treatment, with a 38% decrease in CDK2 activity (P < 0.05) observed in cells treated with 40 µmol/l luteolin. Luteolin inhibited CDK2 activity in a cell-free system, suggesting that it directly inhibits CDK2.

tLuteolin promoted G2/M arrest at 24 hours post-treatment  by down-regulating cyclin B1 expression and inhibiting cell division cycle (CDC)2 activity. Luteolin promoted apoptosis with increased activation of caspases 3, 7, and 9 and enhanced poly(ADP-ribose) polymerase cleavage and decreased expression of p21CIP1/WAF1, survivin, Mcl-1, Bcl-xL, and Mdm-2. Decreased expression of these key antiapoptotic proteins could contribute to the increase in p53-independent apoptosis that was observed in HT-29 cells. Lim et al., (2007) demonstrated that luteolin promotes both cell-cycle arrest and apoptosis in the HT-29 colon cancer cell line, providing insight about the mechanisms underlying its anti-tumorigenic activities.

Pancreatic Cancer; Chemotherapy

Simultaneous treatment or pre-treatment (0, 6, 24 and 42 hours) of flavonoids and chemotherapeutic drugs and various concentrations (0-50µM) were assessed using the MTS cell proliferation assay. Simultaneous treatment with either flavonoid (0,13, 25 or 50µM) and chemotherapeutic drugs 5-fluorouracil (5-FU, 50µM) or gemcitabine (Gem, 10µM) for 60h 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-3βand NF-κB p65 and increased pro-apoptotic cytosolic cytochrome c. Pre-treatment of human pancreatic cancer cells BxPC-3 with low concentrations of Lut effectively aid in the anti-proliferative activity of chemotherapeutic drugs (Johnson et al., 2013).

Ovarian Cancer

Luteolin has been found to repress NF-kappaB (NF-κ>B, a pro-inflammatory transcription factor) and inhibit pro-inflammatory cytokines such as TNF-αand IL-6. Additionally, it has been shown to stabilize p53 protein, sensitize TRAIL (TNF receptor apoptosis-inducing ligand) induced apoptosis, and prevent or delay chemotherapy-resistance.

Recent studies further indicate that luteolin potently inhibits VEGF production and suppresses ovarian cancer cell metastasis in vitro. Lastly, oridonin and wogonin were suggested to suppress ovarian CSCs as is reflected by down-regulation of the surface marker EpCAM. Unlike NSAIDS (non-steroid anti-inflammatory drugs), well documented clinical data for phyto-active compounds are lacking. In order to evaluate objectively the potential benefit of these compounds in the treatment of ovarian cancer, strategically designed, large scale studies are warranted (Chen et al., 2012).

Chemo-sensitizer

The sensitization effect of luteolin on cisplatin-induced apoptosis is p53 dependent, as such effect is only found in p53 wild-type cancer cells but not in p53 mutant cancer cells. Moreover, knockdown of p53 by small interfering RNA made p53 wild-type cancer cells resistant to luteolin and cisplatin. Second, Shi et al., (2007) observed a significant increase of p53 protein level in luteolin-treated cancer cells without increase of p53 mRNA level, indicating the possible effect of luteolin on p53 posttranscriptional regulation.

In summary, data from this study reveal a novel molecular mechanism involved in the anti-cancer effect of luteolin and support its potential clinical application as a chemo-sensitizer in cancer therapy.

Breast Cancer; TAM Chemo-sensitizer

This study found that the level of cyclin E2 (CCNE2) mRNA was higher in tumor cells (4.89-fold, (∗)P=0.005) than in normal paired tissue samples as assessed using real-time reverse-transcriptase polymerase chain reaction (RT-PCR) analysis (n=257). Further, relatively high levels of CCNE2 protein expression were detected in tamoxifen-resistant (TAM-R) MCF-7 cells.

These results showed that the level of CCNE2 protein expression was specifically inhibited in luteolin-treated (5µM) TAM-R cells, either in the presence or absence of 4-OH-TAM (100nM). Combined treatment with 4-OH-TAM and luteolin synergistically sensitized the TAM-R cells to 4-OH-TAM. The results of this study 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).

References

Baliga MS, Jimmy R, Thilakchand 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.


Chen CY, Peng WH, Tsai KD and Hsu SL. (2007). Luteolin suppresses inflammation-associated gene expression by blocking NF-κB and AP-1 activation pathway in mouse alveolar macrophages. Life Sciences, 81(23-24):1602-1614. doi:10.1016/j.lfs.2007.09.028


Chen MZ, Jin WZ, Dai LM, Xu SY. (1986). Effect of luteolin on inflammation and immune function. Chinese Journal of Pharmacology and Toxicology, 1986-01.


Chen SS, Michael A, Butler-Manuel SA. (2012). Advances in the treatment of ovarian cancer: a potential role of anti-inflammatory phytochemicals. Discov Med, 13(68):7-17.


Jang S, Kelley KW, Johnson RW. (2008). Luteolin reduces IL-6 production in microglia by inhibiting JNK phosphorylation and activation of AP-1. PNAS, 105(21):7534-7539


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, S0278-6915(13)00491-2. doi: 10.1016/j.fct.2013.07.036.


Lim DY, Jeong Y, Tyner Al., Park JHY. (2007). Induction of cell-cycle arrest and apoptosis in HT-29 human colon cancer cells by the dietary compound luteolin. Am J Physiol Gastrointest Liver Physiol, 292: G66-G75. doi:10.1152/ajpgi.00248.2006.


Shi R, Huang Q, Zhu X, et al. (2007). Luteolin sensitizes the anti-cancer effect of cisplatin via c-Jun NH2-terminal kinase-mediated p53 phosphorylation and stabilization. Molecular Cancer Therapeutics, 6(4):1338-1347. doi: 10.1158/1535-7163.MCT-06-0638.


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.


Xagorari A, Papapetropoulos A, Mauromatis A, et al. (2001). Luteolin inhibits an endotoxin-stimulated phosphorylation cascade and pro-inflammatory cytokine production in macrophages. JPET, 296(1):181-187.

angiogenesis, Anti-angiogenesis, Anti-angiogenic, anti-tumor, apoptosis, Bladder cancer, Breast cancer, cell-cycle arrest, Chapter 7 Isolates and Cancer Research, chemo-preventive, Cip1/p21, Colon Cancer or Colorectal cancer, EGFR, EMT, epidermal growth factor receptor, ERK, ERK1, Fet, Geo, and HCT116, G1, HL-60, HT-29, Induces cell-cycle arrest, iNOS, Lung cancer, metastasis, Nitric Oxide, p21, PKC, S, Silybum marianum, STAT, STAT3, Thyroid cancer, TNF

Silibinin

Cancer:
Lung, leukemia, colorectal, thyroid, breast, bladder

Action: Anti-angiogenesis, EMT, cell-cycle arrest

Cell-cycle Arrest, Colon Cancer

Silibinin, an active constituent of milk thistle (Silybum marianum [(L.) Gaertn.]), has been reported to inhibit proliferation and induce cell-cycle arrest of human colon cancer cells, Fet, Geo, and HCT116 (Hogan et al., 2007). Silibinin Up-regulates the expression of cyclin-dependent kinase inhibitors and induces cell-cycle arrest and apoptosis in human colon carcinoma HT-29 cells (Agarwal et al., 2003). Also in HT-29 cells, treatment with beta-escin, a principal component of horse chestnut, tinduces growth arrest at the G1-S phase together with an induction of Cip1/p21 and an associated reduction in the phosphorylation of retinoblastoma protein (Patlolla et al., 2006).

Lung Cancer

Silibinin also has anti-angiogenic effects on lung adenocarcinomas in vitro, as it strongly decreased both tumor number and tumor size (an anti-tumor effect that correlates with reduced anti-angiogenic activity) (Tyagi et al., 2009). Further, silibinin inhibits mouse lung tumorigenesis in vivo, in part by targeting tumor microenvironment. Tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) can be pro- or anti-tumorigenic, but in lung cancer cell lines they induce pro-inflammatory enzymes cyclooxygenase 2 (COX2) and inducible nitric oxide synthase (iNOS). Accordingly, the mechanism of silibinin action was examined on TNF-α + IFN-γ (hereafter referred as cytokine mixture) elicited signaling in tumor-derived mouse lung epithelial LM2 cells.

Both signal transducers and activators of the transcription (STAT)3 (tyr705 and ser727) and STAT1 (tyr701) were activated within 15 min of cytokine mixture exposure, while STAT1 (ser727) activated after 3 h. Cytokine mixture also activated Erk1/2 and caused an increase in both COX2 and iNOS levels. Pre-treatment of cells with a MEK, NF-κB, and/or epidermal growth factor receptor (EGFR) inhibitor inhibited cytokine mixture-induced activation of Erk1/2, NF-κB, or EGFR, respectively, and strongly decreased phosphorylation of STAT3 and STAT1 and expression of COX2 and iNOS.

Together, the results show that STAT3 and STAT1 could be valuable chemo-preventive and therapeutic targets within the lung tumor microenvironment in addition to being targets within the tumor itself, and that silibinin inhibit their activation as a plausible mechanism of its efficacy against lung cancer (Tyagi et al., 2011).

Leukemia

Silibinin also affects cellular differentiation in the human promyelocytic leukemia HL-60 cell culture system. Treatment of HL-60 cells with silibinin inhibited cellular proliferation and induced cellular differentiation in a dose-dependent manner.

Silibinin enhanced protein kinase C (PKC) activity and increased protein levels of both PKCα and PKCβ in 1,25-(OH)2D3-treated HL-60 cells. PKC and extracellular signal-regulated kinase (ERK) inhibitors significantly inhibited HL-60 cell differentiation induced by silibinin alone or in combination with 1,25-(OH)2D3, indicating that PKC and ERK may be involved in silibinin-induced HL-60 cell differentiation (Kang et al., 2001).

Thyroid Cancer, Breast Cancer

Silibinin inhibits TPA-induced cell migration and MMP-9 expression in thyroid and breast cancer cells. Matrix metalloproteinases (MMPs) play an important role in cancer metastasis, cell migration and invasion. The effects of silibinin were investigated on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced cell migration and MMP-9 expression in thyroid and breast cancer cells. These results revealed that the levels of MMP-9 mRNA and protein expression were significantly increased by TPA but not MMP-2 in TPC-1 and MCF7 cells.

TPA-induced phosphorylation of MEK and ERK was also inhibited by silibinin. Taken together, these results suggest that silibinin suppresses TPA-induced cell migration and MMP-9 expression through the MEK/ERK-dependent pathway in thyroid and breast cancer cells (Oh et al., 2013).

Bladder Cancer

Silibinin induced apoptosis and inhibited proliferation of bladder cancer cells and metastasis. In the present study, Wu et al. (2013) utilized a novel highly metastatic T24-L cell model, and found that silibinin treatment not only resulted in the suppression of cell migration and invasion in vitro, but also decreased bladder cancer lung metastasis and prolonged animal survival in vivo. Inactivation of β-catenin/ZEB1 signaling by silibinin leads to dual-block of EMT and stemness.

Lung Cancer, EMT

Silibinin formulation might facilitate the design of clinical trials to test the administration of silibinin meglumine-containing injections, granules, or beverages in combination with EGFR TKIs in patients with EGFR-mutated NSCLC. Silibinin meglumine notably decreased the overall volumes of NSCLC tumors as efficiently as did the EGFR tyrosine kinase inhibitor (TKI) gefitinib. Concurrent treatment with silibinin meglumine impeded the regrowth of gefitinib-unresponsive tumors, resulting in drastic tumor growth prevention.

Because the epithelial-to-mesenchymal transition (EMT) is required by a multiplicity of mechanisms of resistance to EGFR TKIs, we evaluated the ability of silibinin meglumine to impede the EMT in vitro and in vivo. Silibinin-meglumine efficiently prevented the loss of markers associated with a polarized epithelial phenotype as well as the de novo synthesis of proteins associated with the mesenchymal morphology of transitioning cells (Cuf` et al., 2013).

Breast cancer

Myeloid-derived suppressor cells (MDSC)s increase in blood and accumulate in the tumor microenvironment of tumor-bearing animals, contributing to immune suppression in cancer. Silibinin, a natural flavonoid from the seeds of milk thistle, has been developed as an anti-inflammatory agent and supportive care agent to reduce the toxicity of cancer chemotherapy. The goals of this study were to evaluate the effect of silibinin on MDSCs in tumor-bearing mice and antitumor activity of silibinin in a mouse model of breast cancer. 4T1 luciferase-transfected mammary carcinoma cells were injected into in the mammary fat pad female BALB/c mice, and female CB17-Prkdc Scid/J mice. Silibinin treatment started on day 4 or day 14 after tumor inoculation continued every other day.

Tumor growth was monitored by bioluminescent imaging (BLI) measuring total photon flux. Flow cytometry measured total leukocytes, CD11b+ Gr-1+ MDSC, and T cells in the blood and tumors of tumor-bearing mice. The effects of silibinin on 4T1 cell viability in vitro were measured by BLI. Treatment with silibinin increased overall survival in mice harboring tumors derived from the 4T1-luciferase breast cancer cell line, and reduced tumor volumes and numbers of CD11b+Gr-1+ MDSCs in the blood and tumor, and increased the content of T cells in the tumor microenvironment.

Silibinin failed to inhibit tumor growth in immunocompromised severe combined immunodeficiency mice, supporting the hypothesis that anticancer effect of silibinin is immune-mediated. The antitumor activity of silibinin requires an intact host immune system and is associated with decreased accumulation of blood and tumor-associated MDSCs.

References

 

Agarwal C, Singh RP, Dhanalakshmi S, et al. (2003). Silibinin Up-regulates the expression of cyclin-dependent kinase inhibitors and causes cell-cycle arrest and apoptosis in human colon carcinoma HT-29 cells. Oncogene, 22:8271–8282.

 

Cufí S, Bonavia R, Vazquez-Martin A, Corominas-Faja B, et al. (2013). Silibinin meglumine, a water-soluble form of milk thistle silymarin, is an orally active anti-cancer agent that impedes the epithelial-to-mesenchymal transition (EMT) in EGFR-mutant non-small-cell lung carcinoma cells. Food Chem Toxicol, 60:360-8. doi: 10.1016/j.fct.2013.07.063.

Hogan FS, Krishnegowda NK, Mikhailova M, Kahlenberg MS. (2007). Flavonoid, silibinin, inhibits proliferation and promotes cell-cycle arrest of human colon cancer. J Surg Res, 143:58–65.

Kang SN, Lee MH, Kim KM, Cho D, Kim TS. (2001). Induction of human promyelocytic leukemia HL-60 cell differentiation into monocytes by silibinin: involvement of protein kinase C. Biochemical Pharmacology, 61(12):1487–1495

Oh SJ, Jung SP, Han J, et al. (2013). Silibinin inhibits TPA-induced cell migration and MMP-9 expression in thyroid and breast cancer cells. Oncol Rep, 29(4):1343-8. doi: 10.3892/or.2013.2252.

Patlolla JM, Raju J, Swamy MV, Rao CV. (2006). Beta-escin inhibits colonic aberrant crypt foci formation in rats and regulates the Cell-cycle growth by inducing p21(waf1/cip1) in colon cancer cells. Mol Cancer Ther, 5:1459–1466.

Tyagi A, Singh RP, Ramasamy K, et al. (2009). Growth Inhibition and Regression of Lung Tumors by Silibinin: Modulation of Angiogenesis by Macrophage-Associated Cytokines and Nuclear Factor-κ B and Signal Transducers and Activators of Transcription 3. Cancer Prev Res, 2(1):74-83

Tyagi A, Agarwal C, Dwyer-Nield LD, et al. (2011). Silibinin modulates TNF‐α and IFN ‐γ mediated signaling to regulate COX2 and iNOS expression in tumorigenic mouse lung epithelial LM2 cells. Molecular Carcinogenesis. doi: 10.1002/mc.20851.

Wu K, Ning Z, Zeng J, et al. (2013). Silibinin inhibits β -catenin/ZEB1 signaling and suppresses bladder cancer metastasis via dual-blocking epithelial-mesenchymal transition and stemness. Cell Signal, 25(12):2625-2633. doi: 10.1016/j.cellsig.2013.08.028.

Forghani P, Khorramizadeh MR & Waller EK. (2014) Silibinin inhibits accumulation of myeloid-derived suppressor cells and tumor growth of murine breast cancer. Cancer Medicine. Volume 3, Issue 2, pages 215–224, April 2014 DOI: 10.1002/cam4.186

AhR, Akt, angiogenesis, Anti-angiogenic, anti-apoptotic, Anti-cancer, Anti-cancer effect, anti-inflammatory, anti-oxidant, anti-proliferative, anti-proliferative effect, anti-tumor, anxiolytic, apoptosis, Apoptotic, BAX, Bcl-2, Breast cancer, CAL-27, FaDu, cardio-protective, cardio-protective against Doxorubicin, cardiovascular disease, Causes cell-cycle arrest, CDK4, cell-cycle arrest, Chapter 7 Isolates and Cancer Research, chemo-preventive, Chemoprevention, Colon Cancer or Colorectal cancer, COX-2, Cytostatic, cytotoxic, G1, G2/M, Head and neck cancer, Hep G2,Hep 3B and SK-Hep1, HIF, HL-60/ADR, IL-6, inflammation, iNOS, JNK, MCF-7, T-47D, MDA-MB-231, Nitric Oxide, Oral cancer, Ovarian cancer, Ovarian cancer cell lines, OVCAR-3, CP-70, IOSE-364, p53, Prostate cancer, ROS, S, VEGF, VEGF, XIAP

Baicalin & Baicalein

Cancer:
Myeloma, liver, colorectal., breast, prostate, oral., hepatoma, ovarian

Action: Anti-cancer, cardiovascular disease, cytostatic, cardio-protective against Doxorubicin, anti-inflammatory, angiogenesis

Baicalin and baicalein are naturally occurring flavonoids that are found in the roots and leaves of some Chinese medicinal plants (including Scutellaria radix, Scutellaria rivularis (Benth.); Scutellaria baicalensis (Georgi) and Scutellaria lateriflora (L.)) are thought to have anti-oxidant activity and possible anti-angiogenic, anti-cancer, anxiolytic, anti-inflammatory and neuroprotective activities. In particular, Scutellaria baicalensis is one of the most popular and multi-purpose herbs used in China traditionally for treatment of inflammation, hypertension, cardiovascular diseases, and bacterial and viral infections (Ye et al., 2002; Zhang et al., 2011a).

Anti-cancer

Accumulating evidence demonstrates that Scutellaria also possesses potent anti-cancer activities. The bioactive components of Scutellaria have been confirmed to be flavones, wogonin, baicalein and baicalin. These phytochemicals are not only cytostatic but also cytotoxic to various human tumor cell lines in vitro and inhibit tumor growth in vivo. Most importantly, they show almost no or minor toxicity to normal epithelial and normal peripheral blood and myeloid cells. The anti-tumor functions of these flavones are largely due to their abilities to scavenge oxidative radicals, to attenuate NF-kappaB activity, to inhibit several genes important for regulation of the cell-cycle, to suppress COX-2 gene expression and to prevent viral infections (Li, 2008).

Multiple Myeloma

In the search for a more effective adjuvant therapy to treat multiple myeloma (MM), Ma et al. (2005) investigated the effects of the traditional Chinese herbal medicines Huang-Lian-Jie-Du-Tang (HLJDT), Gui-Zhi-Fu-Ling-Wan (GZFLW), and Huang-Lian-Tang (HLT) on the proliferation and apoptosis of myeloma cells. HLJDT inhibited the proliferation of myeloma cell lines and the survival of primary myeloma cells, especially MPC-1- immature myeloma cells, and induced apoptosis in myeloma cell lines via a mitochondria-mediated pathway by reducing mitochondrial membrane potential and activating caspase-9 and caspase-3.

Further experiments confirmed that Scutellaria radix was responsible for the suppressive effect of HLJDT on myeloma cell proliferation, and the baicalein in Scutellaria radix showed strong growth inhibition and induction of apoptosis in comparison with baicalin or wogonin. Baicalein as well as baicalin suppressed the survival in vitro of MPC-1- immature myeloma cells rather than MPC-1+ myeloma cells from myeloma patients.

Baicalein inhibited the phosphorylation of IkB-alpha, which was followed by decreased expression of the IL-6 and XIAP genes and activation of caspase-9 and caspase-3. Therefore, HLJDT and Scutellaria radix have an anti-proliferative effect on myeloma cells, especially MPC-1- immature myeloma cells, and baicalein may be responsible for the suppressive effect of Scutellaria radix by blocking IkB-alpha degradation (Ma, 2005).

Hepatoma

The effects of the flavonoids from Scutellaria baicalensis Georgi (baicalein, baicalin and wogonin) in cultured human hepatoma cells (Hep G2, Hep 3B and SK-Hep1) were compared by MTT assay and flow cytometry. All three flavonoids dose-dependently decreased the cell viabilities accompanying the collapse of mitochondrial membrane potential and the depletion of glutathione content. However, the influence of baicalein, baicalin or wogonin on cell-cycle progression was different.

All three flavonoids resulted in prominent increase of G2/M population in Hep G2 cells, whereas an accumulation of sub G1 (hypoploid) peak in Hep 3B cells was observed. In SK-Hep1 cells, baicalein and baicalin resulted in a dramatic boost in hypoploid peak, but wogonin mainly in G1 phase accumulation. These data, together with the previous findings in other hepatoma cell lines, suggest that baicalein, baicalin and wogonin might be effective candidates for inducing apoptosis or inhibiting proliferation in various human hepatoma cell lines (Chang, 2002).

Long dan xie gan tang (pinyin) is one of the most commonly used herbal formulas by patients with chronic liver disease in China. Accumulated anecdotal evidence suggests that Long dan tang may have beneficial effects in patients with hepatocellular carcinoma. Long dan tang is comprised of five herbs: Gentiana root, Scutellaria root, Gardenia fruit, Alisma rhizome, and Bupleurum root. The cytotoxic effects of compounds from the five major ingredients isolated from the above plants, i.e. gentiopicroside, baicalein, geniposide, alisol B acetate and saikosaponin-d, were investigated, respectively, on human hepatoma Hep3B cells..

Interestingly, baicalein by itself induced an increase in H(2)O(2) generation and the subsequent NF-kappaB activation; furthermore, it effectively inhibited the transforming growth factor-beta(1) (TGF-beta(1))-induced caspase-3 activation and cell apoptosis. Results suggest that alisol B acetate and saikosaponin-d induced cell apoptosis through the caspase-3-dependent and -independent pathways, respectively. Instead of inducing apoptosis, baicalein inhibits TGF-beta(1)-induced apoptosis via increase in cellular H(2)O(2) formation and NF-kappaB activation in human hepatoma Hep3B cells (Chou, Pan, Teng & Guh, 2003).

Ovarian Cancer

Ovarian cancer is one of the primary causes of death for women all through the Western world. Two kinds of ovarian cancer (OVCAR-3 and CP-70) cell lines and a normal ovarian cell line (IOSE-364) were selected to be investigated in the inhibitory effect of baicalin and baicalein on cancer cells. Largely, baicalin and baicalein inhibited ovarian cancer cell viability in both ovarian cancer cell lines with LD50 values in the range of 45-55 µM for baicalin and 25-40 µM for baicalein. On the other hand, both compounds had fewer inhibitory effects on normal ovarian cells viability with LD50 values of 177 µM for baicalin and 68 µM for baicalein.

Baicalin decreased expression of VEGF (20 µM), cMyc (80 µM), and NFkB (20 µM); baicalein decreased expression of VEGF (10 µM), HIF-1α (20 µM), cMyc (20 µM), and NFkB (40 µM). Therefore baicalein is more effective in inhibiting cancer cell viability and expression of VEGF, HIF-1α, cMyc, and NFκB in both ovarian cancer cell lines. It seems that baicalein inhibited cancer cell viability through the inhibition of cancer promoting genes expression including VEGF, HIF-1α, cMyc, and NFκB.

Overall, this study showed that baicalein and baicalin significantly inhibited the viability of ovarian cancer cells, while generally exerting less of an effect on normal cells. They have potential for chemoprevention and treatment of ovarian cancers (Chen, 2013).

Breast Cancer

Baicalin was found to be a potent inhibitor of mammary cell line MCF-7 and ductal breast epithelial tumor cell line T-47D proliferation, as well as having anti-proliferative effects on other cancer types such as the human head and neck cancer epithelial cell lines CAL-27 and FaDu. Overall, baicalin inhibited the proliferation of human breast cancer cells and CAL-27 and FaDu cells with effective potency (Franek, 2005).

Breast Cancer, Cell Invasion

The effect of Baicalein on cell viability of the human breast cancer MDA-MB-231 cell line was tested by MTT. 50, 100 µmol·L-1 of Baicalein inhibited significantly cell invasion(P0.01) and migration(P0.01) compared with control groups. The inhibitory rates were 50% and 77% in cell migration and 15% and 44% in cell invasion, respectively. 50 µmol·L-1 of Baicalein significantly inhibited the level of MMP 2 expression. 100 µmol·L-1 of Baicalein significantly inhibited the level of MMP 9 and uPA expressions.

Baicalein inhibits invasion and migration of MDA-MB-231 cells. The mechanisms may be involved in the direct inhibition of cell invasion and migration abilities, and the inhibition of MMP 2, MMP 9, and uPA expressions (Wang et al., 2010).

The proliferation of MDA-MB-231 cell line human breast adenocarcinoma was inhibited by baicalin in a dose-and time-dependent manner and the IC50 was 151 µmol/L. The apoptotic rate of the baicalin-treated MDA-MB-231 cells increased significantly at 48 hours. Flow cytometer analysis also revealed that most of the baicalin-treated MDA-MB-231 cells were arrested in the G2/M phase. Typically apoptotic characteristics such as condensed chromatin and apoptotic bodies were observed after being treated with baicalin for 48 hours.

The results of RT-PCR showed that the expression of bax was up-regulated; meanwhile, the expression of bcl-2 was down-regulated. Baicalin could inhibit the proliferation of MDA-MB-231 cells through apoptosis by regulating the expression of bcl-2, bax and intervening in the process of the cell-cycle (Zhu et al., 2008).

Oral Cancer

As an aryl hydrocarbon receptor (AhR) ligand, baicalein at high concentrations blocks AhR-mediated dioxin toxicity. Because AhR had been reported to play a role in regulating the cell-cycle, it is suspected that the anti-cancer effect of baicalein is associated with AhR. The molecular mechanism involved in the anti-cancer effect of baicalein in oral cancer cells HSC-3 has been investigated, including whether such an effect would be AhR-mediated. Results revealed that baicalein inhibited cell proliferation and increased AhR activity in a dose-dependent manner. Cell-cycle was arrested at the G1 phase and the expression of CDK4, cyclin D1, and phosphorylated retinoblastoma (pRb) was decreased.

When cells were pre-treated with LiCl, the inhibitor of GSK-3β, the decrease of cyclin D1 was blocked and the reduction of pRb was recovered. The data indicates that in HSC-3 the reduction of pRb is mediated by baicalein both through activation of AhR and facilitation of cyclin D1 degradation, which causes cell-cycle arrest at the G1 phase, and results in the inhibition of cell proliferation (Cheng, 2012).

Anti-inflammatory

Baicalin has also been examined for its effects on LPS-induced nitric oxide (NO) production and iNOS and COX-2 gene expressions in RAW 264.7 macrophages. The results indicated that baicalin inhibited LPS-induced NO production in a concentration-dependent manner without a notable cytotoxic effect on these cells. The decrease in NO production was consistent with the inhibition by baicalin of LPS-induced iNOS gene expression (Chen, 2001)

Angiogenesis Modulation

The modulation of angiogenesis is one possible mechanism by which baicalin may act in the treatment of cardiovascular diseases. This may be elucidated by investigating the effects of baicalin on the expression of vascular endothelial growth factor (VEGF), a critical factor for angiogenesis. The effects of baicalin and an extract of S. baicalensis on VEGF expression were tested in several cell lines. Both agents induced VEGF expression in all cells without increasing expression of hypoxia-inducible factor-1alpha (HIF-1alpha).

Their ability to induce VEGF expression was suppressed once ERRalpha expression was knocked down by siRNA, or ERRalpha-binding sites were deleted in the VEGF promoter. It was also found that both agents stimulated cell migration and vessel sprout formation from the aorta. These results therefore implicate baicalin and S. baicalensis in angiogenesis by inducing VEGF expression through the activation of the ERRalpha pathway (Zhang, 2011b).

Colon Cancer

The compounds of baicalein and wogonin, derived from the Chinese herb Scutellaria baicalensis, were studied for their effect in suppressing the viability of HT-29 human colon cancer cells. Following treatment with baicalein or wogonin, several apoptotic events were observed, including DNA fragmentation, chromatin condensation and increased cell-cycle arrest at the G1 phase. Baicalein and wogonin decreased Bcl-2 expression, whereas the expression of Bax was increased in a dose-dependent manner when compared to the control.

The results indicated that baicalein induced apoptosis via Akt activation, in a p53-dependent manner, in HT-29 colon cancer cells. Baicalein may serve as a chemo-preventive, or therapeutic, agent for HT-29 colon cancer (Kim et al., 2012).

Cardio-protective

The cardiotoxicity of doxorubicin limits its clinical use in the treatment of a variety of malignancies. Previous studies suggest that doxorubicin-associated cardiotoxicity is mediated by reactive oxygen species (ROS)-induced apoptosis. Baicalein attenuated phosphorylation of JNK induced by doxorubicin. Co-treatment of cardiomyocytes with doxorubicin and JNK inhibitor SP600125 (10 µM; 24 hours) reduced JNK phosphorylation and enhanced cell survival., suggesting that the baicalein protection against doxorubicin cardiotoxicity was mediated by JNK activation. Baicalein adjunct treatment confers anti-apoptotic protection against doxorubicin-induced cardiotoxicity without compromising its anti-cancer efficacy (Chang et al., 2011).

Prostate Cancer

There are four compounds capable of inhibiting prostate cancer cell proliferation in Scutellaria baicalensis: baicalein, wogonin, neobaicalein, and skullcapflavone. Comparisons of the cellular effects induced by the entire extract versus the four-compound combination produced comparable cell-cycle changes, levels of growth inhibition, and global gene expression profiles (r(2) = 0.79). Individual compounds exhibited anti-androgenic activities with reduced expression of the androgen receptor and androgen-regulated genes. In vivo, baicalein (20 mg/kg/d p.o.) reduced the growth of prostate cancer xenografts in nude mice by 55% at 2 weeks compared with placebo and delayed the average time for tumors to achieve a volume of approximately 1,000 mm(3) from 16 to 47 days (P < 0.001).

Most of the anti-cancer activities of S. baicalensis can be recapitulated with four purified constituents that function in part through inhibition of the androgen receptor signaling pathway (Bonham et al., 2005)

Cancer: Acute lymphocytic leukemia, lymphoma and myeloma

Action: Cell-cycle arrest, induces apoptosis

Scutellaria baicalensis (S.B.) is a widely used Chinese herbal medicine. S.B inhibited the growth of acute lymphocytic leukemia (ALL), lymphoma and myeloma cell lines by inducing apoptosis and cell cycle arrest at clinically achievable concentrations. The anti-proliferative effectwas associated with mitochondrial damage, modulation of the Bcl family of genes, increased level of the CDK inhibitor p27KIP1 and decreased level of c-myc oncogene. HPLC analysis of S.B. showed it contains 21% baicalin and further studies confirmed it was the major anti-cancer component of S.B. Thus, Scutellaria baicalensis should be tested in clinical trials for these hematopoietic malignancies (Kumagai et al., 2007).

References

Bonham M, Posakony J, Coleman I, Montgomery B, Simon J, Nelson PS. (2005). Characterization of chemical constituents in Scutellaria baicalensis with antiandrogenic and growth-inhibitory activities toward prostate carcinoma. Clin Cancer Res, 11(10):3905-14.


Chang WH Chen CH Lu FJ. (2002). Different Effects of Baicalein, Baicalin and Wogonin on Mitochondrial Function, Glutathione Content and cell-cycle Progression in Human Hepatoma Cell Lines. Planta Med, 68(2):128-32. doi: 10.1055/s-2002-20246


Chang WT, Li J, Huang HH, et al. (2011). Baicalein protects against doxorubicin-induced cardiotoxicity by attenuation of mitochondrial oxidant injury .and JNK activation. J Cell Biochem. doi: 10.1002/jcb.23201.


Chen J, Li Z, Chen AY, Ye X, et al. (2013). Inhibitory effect of baicalin and baicalein on ovarian cancer cells. Int J Mol Sci, 14(3):6012-25. doi: 10.3390/ijms14036012.


Chen YC, Shen SC, Chen LG, Lee TJ, Yang LL. (2001). Wogonin, baicalin, and baicalein inhibition of inducible nitric oxide synthase and cyclooxygenase-2 gene expressions induced by nitric oxide synthase inhibitors and lipopolysaccharide. Biochem Pharmacol,61(11):1417-27. doi:10.1016/S0006-2952(01)00594-9


Cheng YH, Li LA, Lin P, et al. (2012). Baicalein induces G1 arrest in oral cancer cells by enhancing the degradation of cyclin D1 and activating AhR to decrease Rb phosphorylation. Toxicol Appl Pharmacol, 263(3):360-7. doi: 10.1016/j.taap.2012.07.010.


Chou CC, Pan SL, Teng CM, & Guh JH. (2003). Pharmacological evaluation of several major ingredients of Chinese herbal medicines in human hepatoma Hep3B cells. European Journal of Pharmaceutical Sciences, 19(5), 403-12.


Franek KJ, Zhou Z, Zhang WD, Chen WY. (2005). In vitro studies of baicalin alone or in combination with Salvia miltiorrhiza extract as a potential anti-cancer agent. Int J Oncol, 26(1):217-24.


Kim SJ, Kim HJ, Kim HR, et al. (2012). Anti-tumor actions of baicalein and wogonin in HT-29 human colorectal cancer cells. Molecular Medicine Reports, 6(6):1443-1449. doi: 10.3892/mmr.2012.1085.


Li-Weber M. (2009). New therapeutic aspects of flavones: The anti-cancer properties of Scutellaria and its main active constituents Wogonin, Baicalein and Baicalin. Cancer Treat Rev, 35(1):57-68. doi: 10.1016/j.ctrv.2008.09.005.


Ma Z, Otsuyama K, Liu S, et al. (2005). Baicalein, a component of Scutellaria radix from Huang-Lian-Jie-Du-Tang (HLJDT), leads to suppression of proliferation and induction of apoptosis in human myeloma cells. Blood, 105(8):3312-8. doi:10.1182/blood-2004-10-3915.


Wang Xf, Zhou Qm, Su Sb. (2010). Experimental study on Baicalein inhibiting the invasion and migration of human breast cancer cells. Zhong Guo Yao Li Xue Tong Bao, 26(6): 745-750.


Zhang XW, Li WF, Li WW, et al. (2011a). Protective effects of the aqueous extract of Scutellaria baicalensis against acrolein-induced oxidative stress in cultured human umbilical vein endothelial cells. Pharm Biol, 49(3): 256–261. doi:10.3109/13880209.2010.501803.


Ye F, Xui L, Yi J, Zhang, W, Zhang DY. (2002). Anti-cancer activity of Scutellaria baicalensis and its potential mechanism. J Altern Complement Med, 8(5):567-72.


Zhang K, Lu J, Mori T, et al. (2011b). Baicalin increases VEGF expression and angiogenesis by activating the ERR{alpha}/PGC-1{alpha} pathway.[J]. Cardiovascular Research, 89(2):426-435.


Zhu Gq, Tang Lj, Wang L, Su Jj, et al. (2008). Study on Baicalin Induced Apoptosis of Human Breast Cancer Cell Line MDA-MB-231. An Hui Zhong Yi Xue Yuan Xue Bao, 27(2):20-23

Kumagai T, et al. (2007) Scutellaria baicalensis, a herbal medicine: Anti-proliferative and apoptotic activity against acute lymphocytic leukemia, lymphoma and myeloma cell lines. Leukemia Research 31 (2007) 523-530

Akt, angiogenesis, Anti-cancer, anti-inflammatory, anti-oxidant, anti-proliferative, AP-1, apoptosis, Apoptotic, Bcl-xL, Breast cancer, BxPC-3, c-Jun, CCNE2, CDK, CDK2, CDK4, cell-cycle arrest, Chapter 7 Isolates and Cancer Research, chemo-enhancing, chemo-preventive, Chemo-sensitizer, chemo-sensitizing, chemo-sensitzer, Colon Cancer or Colorectal cancer, COX-2, CSCs, EpCAM, G1, G2/M, hepato-protective, HT-29, IKK, IL-6, Immunomodulatory, including Terminalia chebula, inflammation, inhibits VEGF, iNOS, JNK, Lung cancer, Mcl-1, Ovarian cancer, p53, p65, Pancreatic cancer, Pro-apoptotic, Radio-protective, Radio-sensitizer, ROS, TAM resistance, TNF, VEGF, VEGF

Luteolin

Cancer: Colorectal., ovarian, pancreatic

Action: Anti-inflammatory, immunomodulatory, radio-sensitizer, chemo-sensitizer

Luteolin is a flavonoid found in many plants and foods, including Terminalia chebula (Retz.), Prunella vulgaris (L.) and Perilla frutescens [(L.) Britton].

Luteolin is contained in Ocimum sanctum L . or Ocimum tenuiflorum L , commonly known as Holy Basil in English or Tulsi in various Indian languages, which is an important medicinal plant in the various traditional and folk systems of medicine in Southeast Asia. Scientific studies have shown it to possess anti-inflammatory, analgesic, anti-pyretic, anti-diabetic, hepato-protective, hypolipidemic, anti-stress, and immunomodulatory activities. It has been found to prevent chemical-induced skin, liver, oral., and lung cancers and mediates these effects by increasing the anti-oxidant activity, altering the gene expressions, inducing apoptosis, and inhibiting angiogenesis and metastasis.

Colon Cancer

Luteolin inhibited cyclin-dependent kinase (CDK)4 and CDK2 activity, resulting in G1 arrest with a concomitant decrease of phosphorylation of retinoblastoma protein. Activities of CDK4 and CDK2 decreased within 2 hours after luteolin treatment, with a 38% decrease in CDK2 activity (P < 0.05) observed in cells treated with 40 µmol/l luteolin. Luteolin also promoted G2/M arrest at 24 hours post-treatment by down-regulating cyclin B1 expression and inhibiting cell division cycle (CDC)2 activity. Luteolin promoted apoptosis with increased activation of caspases 3, 7, and 9 and enhanced poly(ADP-ribose) polymerase cleavage and decreased expression of p21CIP1/WAF1, survivin, Mcl-1, Bcl-xL, and Mdm-2. Lim et al. (2007) demonstrated that luteolin promotes both cell-cycle arrest and apoptosis in the HT-29 colon cancer cell line, providing insight about the mechanisms underlying its anti-tumorigenic activities.

Radio-protective

The aqueous extract of Perilla frutescens has been shown to protect mice against γ-radiation-induced sickness and mortality and to selectively protect the normal tissues against the tumoricidal effects of radiation. The chemo-preventive and radio-protective properties of Perilla emphasize aspects that warrant future research to establish its activity and utility in cancer prevention and treatment (Baliga et al., 2013).

Anti-inflammatory

Pre-treatment of RAW 264.7 macrophages with luteolin, luteolin-7-glucoside, quercetin, and the isoflavonoid genistein inhibited both the LPS-stimulated TNF-α and interleukin-6 release, whereas eriodictyol and hesperetin only inhibited TNF-α release. From the compounds tested, luteolin and quercetin were the most potent in inhibiting cytokine production with an IC50 of less than 1 and 5 µM for TNF-α release, respectively. Moreover, luteolin inhibited LPS-induced phosphorylation of Akt. Treatment of macrophages with LPS resulted in increased IκB-α phosphorylation and reduced the levels of IκB-α. Pre-treatment of cells with luteolin abolished the effects of LPS on IκB-α.

Xagorari et al. (2001) concluded that luteolin inhibits protein tyrosine phosphorylation, nuclear factor-κB-mediated gene expression and pro-inflammatory cytokine production in murine macrophages.

Anti-inflammatory; Neuroinflammation

Pre-treatment of primary murine microglia and BV-2 microglial cells with luteolin inhibited LPS-stimulated IL-6 production at both the mRNA and protein levels. Whereas luteolin had no effect on the LPS-induced increase in NF-κB DNA binding activity, it markedly reduced AP-1 transcription factor binding activity. Consistent with this finding, luteolin did not inhibit LPS-induced degradation of IκB-α but inhibited JNK phosphorylation.

Luteolin consumption reduced LPS-induced IL-6 in plasma 4 hours after injection. Furthermore, luteolin decreased the induction of IL-6 mRNA by LPS in the hippocampus but not in the cortex or cerebellum. Taken together, these data suggest luteolin inhibits LPS-induced IL-6 production in the brain by inhibiting the JNK signaling pathway and activation of AP-1 in microglia. Thus, luteolin may be useful for mitigating neuroinflammation (Jang et al., 2008).

Immunostimulatory and Anti-inflammatory

Luteolin (Lut) possesses significant anti-inflammatory activity in well-established models of acute and chronic inflammation, such as xylene-induced ear edema in mice (ED50= 107 mg/ kg), carrageenin-induced swellingof the ankle, acetic acid-induced pleurisy and croton oil-induced gaseous pouch granuloma in rats. Lut had a marked inhibitory effect on the inflammatory exudation, but did not affect the number of leucocytes. Its combined immunostimulatory and anti-inflammatory activity, and inhibitory effect upon immediate hypersensitive response, provide the pharmacologic bases for the beneficial effects of Lut in the treatment of chronic bronchitis (Chen et al., 1986).

Anti-inflammatory

Luteolin dose-dependently inhibited the expression and production of those inflammatory genes and mediators in macrophages stimulated with lipopolysaccharide (LPS). Semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) assay further confirmed the suppression of LPS-induced TNF- α, IL-6, iNOS and COX-2 gene expression by luteolin at a transcriptional level. Luteolin also reduced the DNA binding activity of nuclear factor-kappa B (NF-κB) in LPS-activated macrophages.

In addition, luteolin significantly inhibited the LPS-induced DNA binding activity of activating protein-1 (AP-1). It was also found that luteolin attenuated the LPS-mediated protein kinase B (Akt) and IKK phosphorylation, as well as reactive oxygen species (ROS) production. In sum, these data suggest that, by blocking NF-κB and AP-1 activation, luteolin acts to suppress the LPS-elicited inflammatory events in mouse alveolar macrophages, and this effect was mediated, at least in part, by inhibiting the generation of reactive oxygen species. These observations suggest a possible therapeutic application of this agent for treating inflammatory disorders in the lung (Chen et al., 2007).

Pancreatic Cancer; Chemo-enhancing

Simultaneous treatment or pre-treatment (0, 6, 24 and 42h) of flavonoids and chemotherapeutic drugs and various concentrations (0-50µM) were assessed using the MTS cell proliferation assay. Pre-treatment for 24 hours with 13µM of either Apigenin or Luteolin, followed by Gem for 36 h 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, 36 hours). Lut (15µM, 24 hours) 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 Lut effectively aid in the anti-proliferative activity of chemotherapeutic drugs (Johnson et al., 2013).

Ovarian Cancer

Recent studies further indicate that luteolin potently inhibits VEGF production and suppresses ovarian cancer cell metastasis in vitro. Lastly, oridonin and wogonin were suggested to suppress ovarian CSCs as is reflected by down-regulation of the surface marker EpCAM.

Unlike NSAIDS (non-steroid anti-inflammatory drugs), well-documented clinical data for phyto-active compounds are lacking. In order to evaluate objectively the potential benefit of these compounds in the treatment of ovarian cancer, strategically designed, large scale studies are warranted (Chen et al., 2012).

Chemo-sensitizer

The sensitization effect of luteolin on cisplatin-induced apoptosis is p53 dependent, as such effect is only found in p53 wild-type cancer cells but not in p53 mutant cancer cells. Moreover, knockdown of p53 by small interfering RNA made p53 wild-type cancer cells resistant to luteolin and cisplatin. The critical role of c-Jun NH(2)-terminal kinase (JNK) was identified in regulation of p53 protein stability: luteolin activates JNK, and JNK then stabilizes p53 via phosphorylation, leading to reduced ubiquitination and proteasomal degradation.

An in vivo nude mice xenograft model confirmed that luteolin enhanced the cancer therapeutic activity of cisplatin via p53 stabilization and accumulation. In summary, data from this study reveal a novel molecular mechanism involved in the anti-cancer effects of luteolin and support its potential clinical application as a chemo-sensitizer in cancer therapy (Shi et al., 2007).

Breast Cancer; Chemo-sensitzer

Luteolin is a flavonoid that has been identified in many plant tissues and exhibits chemo-preventive or chemo-sensitizing properties against human breast cancer. However, the oncogenic molecules in human breast cancer cells that are inhibited by luteolin treatment have not been identified.

Relatively high levels of cyclin E2 (CCNE2) protein expression were detected in tamoxifen-resistant (TAM-R) MCF-7 cells. These results showed that the level of CCNE2 protein expression was specifically inhibited in luteolin-treated (5µM) TAM-R cells, either in the presence or absence of 4-OH-TAM (100nM). Combined treatment with 4-OH-TAM and luteolin synergistically sensitized the TAM-R cells to 4-OH-TAM. The results of this study 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).

References

Baliga MS, Jimmy R, Thilakchand 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.

Chen CY, Peng WH, Tsai KD and Hsu SL. (2007). Luteolin suppresses inflammation-associated gene expression by blocking NF- κ B and AP-1 activation pathway in mouse alveolar macrophages. Life Sciences, 81(23-24):1602-1614. doi:10.1016/j.lfs.2007.09.028

Chen MZ, Jin WZ, Dai LM, Xu SY. (1986). Effect of luteolin on inflammation and immune function. Chinese Journal of Pharmacology and Toxicology, 1986-01.

Chen SS, Michael A, Butler-Manuel SA. (2012). Advances in the treatment of ovarian cancer: a potential role of anti-inflammatory phytochemicals. Discov Med, 13(68):7-17.

Jang S, Kelley KW, Johnson RW. (2008). Luteolin reduces IL-6 production in microglia by inhibiting JNK phosphorylation and activation of AP-1. PNAS, 105(21):7534-7539

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, S0278-6915(13)00491-2. doi: 10.1016/j.fct.2013.07.036.

Lim DY, Jeong Y, Tyner Al., Park JHY. (2007). Induction of cell-cycle arrest and apoptosis in HT-29 human colon cancer cells by the dietary compound luteolin. Am J Physiol Gastrointest Liver Physiol, 292: G66-G75. doi:10.1152/ajpgi.00248.2006.

Shi R, Huang Q, Zhu X, et al. (2007). Luteolin sensitizes the anti-cancer effect of cisplatin via c-Jun NH2-terminal kinase-mediated p53 phosphorylation and stabilization. Molecular Cancer Therapeutics, 6(4):1338-1347. doi: 10.1158/1535-7163.MCT-06-0638.

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.

Xagorari A, Papapetropoulos A, Mauromatis A, et al. (2001). Luteolin inhibits an endotoxin-stimulated phosphorylation cascade and pro-inflammatory cytokine production in macrophages. JPET, 296(1):181-187.