Green Tea
Green tea is rich in catechin polyphenols, particularly epigallocatechin gallate (EGCG). EGCG is a powerful anti-oxidant. Besides inhibiting the growth of cancer cells, it kills cancer cells without harming healthy tissues. EGCG is also effective in reducing inflammation, lowering cardiovascular risk, in obesity, and in other chronic conditions. The suggested daily dose, according to some sources, is 200-400mg EGCG per day. Most of the research showing the health benefits of green tea is based on the amount of green tea typically consumed in Asian countries, which is about 3 cups per day (which would provide 240-320 mg of polyphenols). Some studies have suggested drinking up to 10 cups per day for clinical effects. (For more detailed information, please visit ISM’s searchable database: Nutraceutical Search.)
The anti-carcinogenic and anti-mutagenic activities of green tea were highlighted some years ago suggesting that it could reduce the prevalence of cancer and even provide protection. The pharmacological actions of green tea are mainly attributed to polyphenols that includes epigallocatechin-3-gallate (EGCG)……….Green tea is supposed to enhance humeral and cell-mediated immunity, decreasing the risk of certain cancers, and may have certain advantage in treating inflammatory disorders……….. The review is intended to highlight the chemistry of green tea, its antioxidant potential, its immunopotentiating properties and mode of action against various cancer cell lines that showed its potential as a chemo preventive agent against colon, skin, lung, prostate, and breast cancer.
o Butt, MS, & Sultan, MT. (2009). Green tea: nature's defense against malignancies. Crit Rev Food Sci Nutr, 49(5), 463-73.
Multiple lines of evidence, mostly from population-based studies, suggest that green tea consumption is associated with reduced risk of several human malignancies such as cancer and diabetes. Epigallocatechin-3-gallate (EGCG), a major polyphenol found in green tea, is a widely studied chemopreventive agent with potential anticancer activity. Green tea polyphenols inhibit angiogenesis and metastasis, and induce growth arrest.
o Shankar, S, Ganapathy, S, & Shrivastava, RK. (2007). Green tea polyphenols: biology and therapeutic implications in cancer. Front Biosci, 12, 4881-9.
Green tea is an extremely popular beverage worldwide. Derivatives of green tea, particularly epigallocatechin-3-gallate (EGCG), have been proposed to have anticarcinogenic properties based on preclinical, observational, and clinical trial data. To summarize, clarify, and extend current knowledge, we conducted a comprehensive search of the PubMed database and other secondary data sources…….. EGCG functions as an antioxidant, preventing oxidative damage in healthy cells, but also as an antiangiogenic agent, preventing tumors from developing a blood supply needed to grow larger………… Finally, EGCG exhibits antibacterial activity, which may be implicated in the prevention of gastric cancer.
o Carlson, JR, Bauer, BA, Vincent, A, Limburg, PJ, & Wilson, T. (2007). Reading the tea leaves: anticarcinogenic properties of (-)-epigallocatechin-3-gallate. Mayo Clin Proc, 82(6), 725-32.
Accumulating evidence indicates that consumption of tea, especially green tea, is good for preventing cancer………. much effort has been devoted to investigating the anticancer effects of (-)-epigallocatechin-3-gallate (EGCG), the major component of green tea………. EGCG is a multipotent anticancer agent, which not only provides solid evidence to support the anticancer potential of green tea, but also offers new clues for discovering multiple-targeted anticancer drugs.
o Chen, L, & Zhang, HY. (2007). Cancer preventive mechanisms of the green tea polyphenol (-)-epigallocatechin-3-gallate. Molecules, 12(5), 946-57.
Drinking green tea is associated with decreased frequency of cancer development……green and black tea polyphenols act at numerous points regulating cancer cell growth, survival, and metastasis, including effects at the DNA, RNA, and protein levels.
o Beltz, LA, Bayer, DK, Moss, AL, & Simet, IM. (2006). Mechanisms of cancer prevention by green and black tea polyphenols. Anticancer Agents Med Chem, 6(5), 389-406.
Green tea is an acknowledged cancer preventive in Japan. The aim of this review article is to develop the concept of cancer prevention with green tea beverage for humans, which has largely been our exclusive research territory…………The results of an epidemiological study in Saitama Prefecture allowed us to determine the cancer preventive amount of green tea-10 Japanese-size cups per day, about 2.5 g green tea extract-which made it possible for us to introduce the two-stage strategy of cancer prevention with green tea………….. Combination cancer prevention with green tea and cancer preventive drugs is proving especially beneficial for Japanese, who drink green tea every day.
o Fujiki, H. (2005). Green tea: health benefits as cancer preventive for humans. Chem Rec, 5(3), 119-32.
Modulation of events characteristic of carcinogenesis or of cancer cells is being emphasized as a rational strategy to control cancer. Green tea polyphenol epigallocatechin gallate (EGCG) has been shown to be highly active as a cancer chemopreventive agent. Certain cellular and molecular events relevant to carcinogenesis are also modified by EGCG.
o Roy, M, Chakravarty, S, Sinha, D, Bhattachariya, RK, & Siddiqi, M. (2003). Anticlastogenic, antigenotoxic and apoptotic activity of epigallocatechin gallate: a green tea polyphenol. Mutat Res, 523-524, 33-41.
Green tea and (-)-epigallocatechin gallate (EGCG) are now acknowledged cancer preventives in Japan and has made it possible for us to establish the concept of a cancer preventive beverage. For the general population, we recommend 10 cups of green tea daily supplemented with green tea tablets. For cancer patients following treatment, we here present new evidence that green tea and a cancer preventive drug, sulindac, have synergistic preventive effects.
o Fujiki, H, Suganuma, M, Imai, K, & Nakachi, K. (2002). Green tea: cancer preventive beverage and/or drug. Cancer Lett, 188(1-2), 9-13.
BACKGROUND: Given the association of consumption of green tea with prevention of cancer development, metastasis, and angiogenesis, the effect of the main flavanol present, epigallocatechin-3-gallate (EGCG), on two gelatinases most frequently overexpressed in cancer and angiogenesis and on tumor cell invasion and chemotaxis were examined……….. CONCLUSIONS: Epigallocatechin-3-gallate is a potent inhibitor of gelatinases and an orally available pharmacologic agent that may confer the antiangiogenic and antimetastatic activity associated with green tea.
o Garbisa, L et al. (2001). Tumor gelatinases and invasion inhibited by the green tea flavanol epigallocatechin-3-gallate. Cancer, 91(4), 822-32.
Epidemiological, in vitro cell culture, and in vivo animal studies have shown that green tea or its constituent polyphenols, particularly its major polyphenol epigallocatechin-3-gallate (EGCG) may protect against many cancer types…………. We suggest that the naturally occurring agents such as green tea polyphenols which may inhibit cell cycle progression could be developed as potent anticancer agents for the management of cancer.
o Ahmad, N, Cheng, P, & Mukhtar, H. (2000). Cell cycle dysregulation by green tea polyphenol epigallocatechin-3-gallate. Biochem Biophys Res Commun, 275(2), 328-34.
Worldwide interest in green tea as a cancer preventive agent for humans has increased, because it is non-toxic and it is effective in a wide range of organs. (-)-Epigallocatechin gallate (EGCG) is the main constituent of green tea………… a case-control study on breast cancer patients revealed that high daily consumption of green tea was associated with a lower recurrence rate among Stages I and II patients. All the results suggest that consumption of green tea is a practical and effective cancer preventive both before cancer onset and after cancer treatment.
o Suganuma, M et al. (1999). Green tea and cancer chemoprevention. Mutat Res, 428(1-2), 339-44.
BACKGROUND AND PURPOSE: The polyphenolic compounds present in green tea show cancer chemopreventive effects in many animal tumor models. Epidemiologic studies have also suggested that green tea consumption might be effective in the prevention of certain human cancers. We investigated the effect of green tea polyphenols and the major constituent, epigallocatechin-3-gallate, on the induction of apoptosis (programmed cell death) and regulation of cell cycle in human and mouse carcinoma cells…………CONCLUSIONS: Green tea may protect against cancer by causing cell cycle arrest and inducing apoptosis.
o Ahmad, N, Feyes, DK, Nieminen, AL, Agarwal, R, & Mukhtar, H. (1997). Green tea constituent epigallocatechin-3-gallate and induction of apoptosis and cell cycle arrest in human carcinoma cells. Journal of The National Cancer Institute, 89, 1881-6.
Epidemiological studies suggest that the consumption of green tea may help prevent cancers in humans; also, breast and prostate cancers in animal models are reduced by green, but not black, tea………… We have demonstrated that one of the major ingredients of green tea inhibits urokinase, an enzyme crucial for cancer growth.
o Jankun, J, Selman, SH, Swiercz, R, & Skrzypczak-Jankun, E. (1997). Why Drinking green tea could prevent cancer. Nature, 387(6633), 561.
The Green tea polyphenols (GTP) have been shown to have a protective effect in prostate cancer……….. An inverse association between the risk of breast cancer and the intake of green tea has also been reported in Asian Americans. Several epidemiological studies have shown that breast cancer progression is delayed in the Asian population that consumes green tea on regular basis……… these data sustain our contention that GTP and EGCG (Epigallocatechin Gallate) have anti-tumor properties.
o Thangapazham, RL et al. (2007). Green tea polyphenols and its constituent epigallocatechin gallate inhibits proliferation of human breast cancer cells in vitro and in vivo. Cancer Lett, 245(1-2), 232-41.
Green tea has been suggested for prevention of cancers. In this study, the effect of the main constituent of green tea, epigallocatechin gallate (EGCG), on apoptosis of breast cancer cells was examined……….. These findings suggest that EGCG might be useful in treatment and/or prevention of breast cancer by inducing apoptosis.
o Zhao, X, Tian, H, Ma, X, & Li, L. (2006). Epigallocatechin gallate, the main ingredient of green tea induces apoptosis in breast cancer cells. Front Biosci, 11, 2428-33.
Inhibitory effects of green tea on carcinogenesis have been investigated in numerous laboratory studies using (-)-epigallocatechin gallate (EGCG) or crude green tea extract, and there is also some epidemiologic evidence………… We found that increased consumption of green tea was closely associated with decreased numbers of axillary lymph node metastases among premenopausal patients with stage I and II breast cancer………. Our results indicate that increased consumption of green tea prior to clinical cancer onset is significantly associated with improved prognosis of stage I and II breast cancer.
o Nakachi, K et al. (1998). Influence of drinking green tea on breast cancer malignancy among Japanese patients. Jpn J Cancer Res, 89(3), 254-61.
Green tea and its major constituent epigallocatechin gallate (EGCG) have been extensively studied as a potential treatment for a variety of diseases, including cancer. Epidemiological data have suggested that EGCG may provide protective effects against hormone related cancers, namely breast or prostate cancer.
o Stuart, EC, Scandlyn, MJ, & Rosengren, RJ. (2006). Role of epigallocatechin gallate (egcg) in the treatment of breast and prostate cancer. Life Sci, 79(25), 2329-36.
Epigallocatechin-3-gallate (EGCG), the major polyphenolic constituent present in green tea, is a promising chemopreventive agent. We recently showed that green tea polyphenols exert remarkable preventive effects against prostate cancer……… This is the first systematic study showing…….cell cycle arrest and apoptosis of human prostate carcinoma cells by EGCG.
o Gupta, S, Hussain, T, & Mukhtar, H. (2003). Molecular pathway for (-)-epigallocatechin-3-gallate-induced cell cycle arrest and apoptosis of human prostate carcinoma cells. Arch Biochem Biophys, 410(1), 177-85.
Green tea components exert many biological effects, including antitumor and cancer preventive activities. In the search for anticancer agents for prostate cancer the inhibitory effects of green tea components were tested on the prostate cancer cell lines………… Epigallocatechin-3-gallate (EGCG) proved to be the most potent catechin at inhibiting cell growth…….. Thus, we report the first evidence that EGCG is the active component in green tea and induces apoptosis in human prostate cancer cells.
o Paschka, AG, Butler, R, & Young, CY. (1998). Induction of apoptosis in prostate cancer cell lines by the green tea component, (-)-epigallocatechin-3-gallate. Cancer Lett, 130(1-2), 1-7.
The polyphenol epigallocatechin-3-gallate (EGCG), the principal mediator of the green tea, has been known to possess antitumor effect………. In this study, we examined the green tea and EGCG effects on two ovarian carcinoma cell lines…….. These results provide a novel insight into the mechanism by which EGCG…… may be useful in preventing and treating ovarian carcinoma.
o Spinella , F et al. (2006). Green tea polyphenol epigallocatechin-3-gallate inhibits the endothelin axis and downstream signaling pathways in ovarian carcinoma. Mol Cancer Ther, 55(6), 1483-92.
OBJECTIVE: To investigate the effect of the major tea polyphenol, (-)-epigallocatechin gallate (EGCG) in cervical carcinogenesis…….. CONCLUSION: Our data suggest that EGCG prevents the carcinogenesis of cervical cancer.
o Yokoyama, M, Noguchi, M, Nakao, Y, Pater, A, & Iwasaka, T. (2004). The Tea polyphenol, (-)-epigallocatechin gallate effects on growth, apoptosis, and telomerase activity in cervical cell lines. Gynecol Oncol, 92(1), 197-204.
Purpose: A constituent of green tea, (-)-epigallocatechin-3-gallate (EGCG), has been known to possess anti-cancer properties. In this study, we investigated the time-course anticancer effects of EGCG on human ovarian cancer cells……… Conclusion: EGCG can inhibit ovarian cancer cell growth…….. the EGCG-mediated apoptosis can be applied to an advanced strategy in the development of a potential drug against ovarian cancer.
o Huh, SW et al. (2004). Anticancer effects of (-)-epigallocatechin-3-gallate on ovarian carcinoma cell lines. Gynecol Oncol, 94(3), 760-8.
A constituent of green tea, (-)-epigallocatechin-3-gallate (EGCG) has been known to possess antiproliferative properties. In this study, we investigated the anticancer effects of EGCG in human papillomavirus (HPV)-16 associated cervical cancer cell line………. This data supports that EGCG can inhibit cervical cancer cell growth through induction of apoptosis and cell cycle arrest as well as regulation of gene expression.
o Ahn, WS et al. (2003). A Major constituent of green tea, egcg, inhibits the growth of a human cervical cancer cell line, caski cells, through apoptosis, g(1) arrest, and regulation of gene expression. DNA Cell Biol, 22(3), 217-24.
Epigallocatechin-3-gallate (EGCG), a major polyphenolic constituent of green tea, can exert growth suppressive effect on human pancreatic cancer cells by evoking apoptotic response………. This combination treatment strategy has potential therapeutic advantage for pancreatic carcinoma.
o Basu, A, & Haldar, S. (2009). Combinatorial effect of epigallocatechin-3-gallate and trail on pancreatic cancer cell death.. Int J Oncol, 34(1), 281-6.
Epidemiological data suggest that epigallocatechin-3-gallate (EGCG) possesses chemopreventive properties against cancer. In this study, we examined the molecular mechanisms of EGCG in human pancreatic cancer cells………. Our results suggest that EGCG induces growth arrest and apoptosis through multiple mechanisms, and can be used for pancreatic cancer prevention.
o Shankar, S, Suthakar, G, & Srivastava, RK. (2007). Epigallocatechin-3-gallate inhibits cell cycle and induces apoptosis in pancreatic cancer. Front Biosci, 12, 5039-51.
Epidemiological studies on humans and investigations in animal models suggest that consumption of green tea has anti-cancer effects. Small-cell lung carcinoma (SCLC) has a poor prognosis, particularly due to the development of drug resistance. We investigated the effects of the green tea polyphenol, epigallocatechin-3-gallate (EGCG) on human SCLC cells……….. Data indicate the potential use of EGCG, and possibly green tea, in treating SCLC.
o Sadava, D, Whitlock, E, & Kane, SE. (20076). The Green tea polyphenol, epigallocatechin-3-gallate inhibits telomerase and induces apoptosis in drug-resistant lung cancer cells. Biochem Biophys Res Commun, 360(1), 233-7.
A major polyphenol of green tea, epigallocatechin-3-gallate (EGCG), has previously been shown to induce cell-cycle arrest and apoptosis in various cancers. However, little is known about its effects on hepatocellular carcinomas (HCCs)………. EGCG treatment may be useful for improving the prognosis of HCCs.
o Nishikawa, T et al. (2006). A Green tea polyphenol, epigalocatechin-3-gallate, induces apoptosis of human hepatocellular carcinoma, possibly through inhibition of bcl-2 family proteins. J Hepatol, 44(6), 1074-82.
We investigated the effect of epigallocatechin-gallate (EGCG), the main constituent of green tea polyphenols, on human glioblastoma cell lines………. It can be concluded that EGCG has an inhibitory effect on malignant brain tumors.
o Yokoyama, S, Hirano, H, Wakimaru, N, Sarker, KP, & Kuratsu, J. (2001). Inhibitory effect of epigallocatechin-gallate on brain tumor cell lines in vitro. Neuro Oncol, 3(1), 22-8.
The exposure of human stomach cancer KATO III cells to green tea catechin extract and epigallocatechin gallate (EGCG), a main component of the extract led to both growth inhibition and the induction of programmed cell death………. These data suggest that drinking of green tea in large amounts is recommended possibly to protect humans from stomach cancer.
o Hibasami, H et al. (1998). Induction of apoptosis in human stomach cancer cells by green tea catechins. Oncol Rep, 5(2), 527-9.
Experimental models of stroke provide consistent evidence of smaller stroke volumes in animals ingesting tea components or tea extracts. To assess whether a similar association of black or green tea consumption with reduced risk is evident in human populations, we sought to identify and summarize all human clinical and observational data on tea and stroke……..Regardless of their country of origin, individuals consuming about 3 cups of tea per day had a 21% lower risk of stroke than those consuming <1 cup per day…….. Conclusions: Although a randomized clinical trial would be necessary to confirm the effect, this meta-analysis suggests that daily consumption of either green or black tea equaling 3 cups per day could prevent the onset of ischemic stroke.
o Arab, L, Liu, W, & Elashoff, D. (2009). Green and black tea consumption and risk of stroke. Stroke, 40, 1786-92.
Several different epidemiological studies have examined the association between the consumption of tea and coronary heart disease……….. The aim of this study was to determine the short-to medium-term effect of a green tea extract on vascular function……. This study found that consumption of green tea extract by women for five weeks produced modifications in vascular function.
o Tinahones, FJ et al. (2008). Green tea reduces ldl oxidability and improves vascular function. J Am Coll Nutr, 27(2), 209-13.
Several epidemiological studies have indicated that pronounced cardiovascular and metabolic health benefits can be obtained by regular consumption of 5-6 or more cups of green tea per day………..200-300 mg of EGCG, have demonstrated its usefulness for maintaining cardiovascular and metabolic health.
o Wolfram, S. (2007). Effects of green tea and egcg on cardiovascular and metabolic health. J Am Coll Nutr, 26(4), 373-88.
Recent data from human studies indicate that the consumption of green tea and green tea extracts may help reduce body weight, mainly body fat, by increasing postprandial thermogenesis and fat oxidation……… These findings suggest that EGCG (epigallocatechin gallate) alone has the potential to increase fat oxidation in men and may thereby contribute to the anti-obesity effects of green tea.
o Boschmann, M, & Thielecke, F. (2007). The Effects of epigallocatechin-3-gallate on thermogenesis and fat oxidation in obese men: a pilot study. J Am Coll Nutr, 26(4), 389-95.
Tea has been found to possess widespread biological functions based on a variety of laboratory data. The effects of tea on obesity and diabetes have received increasing attention……… epigallocatechin gallate (EGCG), appear to have antiobesity and antidiabetic effects……….. The mechanistic results of this review may possibly be utilized in the treatment of obesity, diabetes, and other related diseases.
o Kao, YH, Chang, HH, Lee, MJ, & Chen, CL. (2006). Tea, obesity, and diabetes. Mol Nutr Food Res, 50(2), 188-210.
Due to the ever-growing obesity pandemic, the anti-obesity effects of green tea are being increasingly investigated in cell, animal, and human studies…….. Studies conducted with human subjects report reduced body weight and body fat.
o Wolfram, S, Wang, Y, & Thielecke, F. (2006). Anti-obesity effects of green tea: from bedside to bench. Mol Nutr Food Res, 50(2), 176-87.
The inhibition of acid production from dental plaque and mutans streptococci by epigallocatechin gallate (EGCg), one of the green tea catechins, was examined. The effect of EGCg solution on dental plaque pH was investigated…….. These results suggest that EGCg is effective in reducing acid production in dental plaque and mutans streptococci.
o Hirasawa, M, Takada, K, & Otake, S. (2006). Inhibition of acid production in dental plaque bacteria by green tea catechins. Caries Res, 40(3), 265-70.
Green tea catechins have been shown to promote loss of body fat and to inhibit growth of many cancer cell types by inducing apoptosis. The objective of this study was to determine whether epigallocatechin gallate (EGCG), the primary green tea catechin, could act directly on adipocytes to inhibit adipogenesis and induce apoptosis……… These results demonstrate that EGCG could be an important adjunct in the treatment of obesity.
o Lin, J, Della-Fera, MA, & Baile, CA. (2005). Green tea polyphenol epigallocatechin gallate inhibits adipogenesis and induces apoptosis in 3t3-l1 adipocytes. Obes Res, 13(6), 982-90.
Green tea polyphenol catechin has been reported to have antiallergic and anti-inflammatory activities…….. Catechin, especially EGCG (epigallocatechin gallate), by promoting monocytic apoptosis, may be a new promising anti-inflammatory agent.
o Kawai, K et al. (2005). Epigallocatechin gallate induces apoptosis of monocytes. J Allergy Clin Immunol, 115(1), 186-91.