Differential in vitro cytotoxicity of (-)-epicatechin gallate (ECG) to cancer and normal cells from the human oral cavity
Department of Biology, Stern College for Women, Yeshiva University, 245 Lexington Avenue, New York, NY 10016, USA.Toxicology in Vitro (Impact Factor: 2.9). 04/2005; 19(2):231-42. DOI: 10.1016/j.tiv.2004.09.001
This study evaluated the biologic activity of epicatechin gallate (ECG), a polyphenol in tea, to carcinoma HSC-2 cells and normal HGF-2 fibroblasts cells from the human oral cavity. The relative cytotoxicity of ECG, as compared to five other polyphenols in tea, was evaluated. For the HSC-2 carcinoma cells, ECG, catechin gallate (CG), and epigallocatechin gallate (EGCG) grouped as highly toxic, epigallocatechin (EGC) as moderately toxic, and catechin (C) and epicatechin (EC) as least toxic. For the HGF-2 fibroblasts, ECG and CG grouped as highly toxic, EGCG as moderately toxic, and EGC, C, and EC as least toxic. The cytotoxic effects of the polyphenols were more pronounced to the carcinoma, than to the normal, cells. The addition of ECG to cell culture medium led to the generation of hydrogen peroxide (H2O2). However, ECG, as compared to EGCG, was a poor generator of H2O2 and, hence, the cytotoxicity of ECG was unaffected by the presence of the antioxidants, N-acetyl cysteine and glutathione, and catalase. The cytotoxicity of ECG was unaffected by a metabolic activating system, i.e., a hepatic microsomal S-9 mix. DNA fragmentation, caspase-3 activity, and nuclear staining, both with acridine orange and the TUNEL procedure, were used to assess ECG-induced apoptosis. ECG induced apoptosis in the carcinoma HSC-2 cells, but not in the normal HGF-2 fibroblasts. This research supports those studies suggesting that tea green is an effective chemopreventive agent of oral carcinoma.
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- "It was followed by 2S, 3R-3, 3′, 4′, 5, 7-pentahydroxyflavane-5-O-gallate (1), with IC50 ranging from 11.6 to 38.8 μg/ml. This is also in agreement with previously reported studies. The weakest anticancer activity was given by 2S,3R-3, 3′,4′, 5, 5′, 7-hexahydroxyflavane-3′, 5-di-O-gallate (2) with IC50 ranging from 39.8 to above 50 μg/ml, compared to vinblastine sulphate as reference drug. "
ABSTRACT: Background:Previous investigation of the methanol extract of Plicosepalus curviflorus leaves led to the isolation of two new flavane gallates (1, 2), together with other compounds including quercetin (3). The stems of P. curviflorus are used traditionally for the treatment of cancer in Yemen.Objective:The aim of this study was to evaluate the anticancer activity of the plant methanol extract as well as isolated compounds (1-3).Materials and Methods:The human cancer cell lines used were; MCF-7, HepG-2, HCT-116, Hep-2, HeLa and normal, Vero cell line using the Crystal Violet Staining method (CVS).Results:Quercetin (3) possessed the highest anticancer effect against all five cell lines (IC50 ranging from 3.6 to 16.2 μg/ml). It was followed by 2S, 3R-3, 3′, 4′, 5, 7-pentahydroxyflavane-5-O-gallate (1), with IC50 ranging from 11.6 to 38.8 μg/ml. The weakest anticancer activity was given by 2S, 3R-3,3′,4′,5,5′,7-hexahydroxyflavane-3′,5-di-O-gallate (2) with IC50 ranging from 39.8 to above 50 μg/ml, compared to vinblastine sulphate as reference drug. Colon, liver and breast cell lines seemed to be more sensitive to the tested compounds than the cervical and laryngeal cell lines. Concerning the cytotoxic effect on Vero cell line, the pentahydroxyflavane-5-O-gallate (1) showed the highest IC50 ( 138.2 μg/ml), while quercetin exhibited the lowest IC50 to Vero cells (30.5 μg/ml), compared to vinblastine sulphate as reference drug (IC50: 39.7 μg/ml).Conclusion:The results suggest the possible use of compounds 1 and 3 as anticancer drugs especially against colon and liver cancers.
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- "Human oral squamous cell carcinoma In vitro Epigallocatechin-3 gallate and catechin gallate Positive cytotoxicity, Babich et al. (2005) Human oral squamous cell carcinoma In vitro Mate tea products Catalytic anti-topoisomerase activity and positive cytotoxicity, Gonzalez de Mejia et al. (2005) Human oral squamous cell carcinoma In vitro Curcumin and quercetin Inhibition of cell growth and cellular DNA synthesis, Haghiac and Walle (2005) Head and neck cancer In vivo Gossypol Inhibition of tumor growth and induction of apoptosis, Wolter et al. (2006) Hamster In vivo Black tea polyphenols Reduced incidence of tumor, Chandra Mohan et al. (2006) Human oral cell lines In vitro Catechin gallate Positive cytotoxicity, Babich et al. (2007) Normal fibroblast and oral squamous cell carcinoma In vitro Green (Polyphenon-E; P-E) and black tea polyphenols (Polyphenon-B; P-B) "
ABSTRACT: Polyphenols are present in foods and beverages, being related to sensorial qualities such as color, bitterness, and astringency, which are relevant in products such as wine, tea, and grape juice. These compounds occur naturally in forms varying from simple phenolic acids to complex polymerized tannins. Oral cancer is the most common head and neck cancer, and it often has a poor prognosis owing to local tumor invasion and frequent lymph node metastasis. Nowadays, chemoprevention is considered as a promising approach for controlling cancer as a result of specific natural products or synthetic agents able to suppress, reverse, or even prevent premalignancy before transformation into invasive cancer. The use of polyphenols as a chemopreventive agent is a suitable tool for modulation of the oral carcinogenesis process. The aim of this article is to present data generated from the use of polyphenols as a chemopreventive agent in oral carcinogenesis using in-vivo and in-vitro test systems. These results have shown that polyphenols are able to exert some chemopreventive action as a result of inducing cellular death, apoptosis, inhibition of tumor growth, and antioxidative properties. Therefore, this area warrants further investigation as a new approach that would apply not only to polyphenols but also to other phytochemicals used as promising therapeutic agents against oral human diseases, especially cancer.
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- "Therefore , new medications are required to block infection and to prevent viral shedding by an infected individual (Morfin and Thouvenot, 2003). EGCG has been reported to lack marked cytotoxic effects on non-cancerous cells (Babich et al., 2005; Weisburg et al., 2004). Data presented here indicate that both EGCG and p-EGCG have similar cytotoxicity towards African green monkey kidney-derived Vero cells at concentrations up to 75 lM. "
ABSTRACT: Green tea polyphenol epigallocatechin gallate (EGCG) is a strong antioxidant that has previously been shown to reduce the number of plaques in HIV-infected cultured cells. Modified EGCG, palmitoyl-EGCG (p-EGCG), is of interest as a topical antiviral agent for herpes simplex virus (HSV-1) infections. This study evaluated the effect of p-EGCG on HSV-infected Vero cells. Results of cell viability and cell proliferation assays indicate that p-EGCG is not toxic to cultured Vero cells and show that modification of the green tea polyphenol epigallocatechin gallate (EGCG) with palmitate increases the effectiveness of EGCG as an antiviral agent. Furthermore, p-EGCG is a more potent inhibitor of herpes simplex virus 1 (HSV-1) than EGCG and can be topically applied to skin, one of the primary tissues infected by HSV. Viral binding assay, plaque forming assay, PCR, real-time PCR, and fluorescence microscopy were used to demonstrate that p-EGCG concentrations of 50μM and higher block the production of infectious HSV-1 particles. p-EGCG was found to inhibit HSV-1 adsorption to Vero cells. Thus, p-EGCG may provide a novel treatment for HSV-1 infections.
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