Mechanistic findings of green tea as cancer preventive for humans

Based on our initial work with green tea, in which repeated topical applica tions of (-)-epigallocatechin gallate (EGCG), the main green tea polyphenol , inhibited tumor promotion in a two-stage carcinogenesis experiment on mou se skin (Phytother Res 1, 44-47, 1987), numerous scientists have since prov ided so much additional evidence of the benefits of drinking green tea that it is now an acknowledged cancer preventive in Japan, and will possibly so on be recognized as such in other countries. Our work has so far produced s everal important results with EGCG end green tea: a wide range of target or gans in animal experiments for cancer prevention, wide bioavailability of H -3-EGCG in various organs of mice, delayed cancer onset of patients with a history of consuming over 10 cups of green tea per day, and absence of any severe adverse effects among volunteers who took 15 green tea tablets per d ay (2.25 g green tea extracts, 337.5 mg EGCG, and 135 mg caffeine) for 6 mo nths, This paper introduces three new findings: 1) EGCG interacted with the phospholipid bilayer membrane resulting in confirmation of the sealing eff ect of EGCG; 2) EGCG inhibited TNF-alpha gene expression in the cells and T NF-alpha release from the cells; 3) high consumption of green tea was close ly associated with decreased numbers of axillary lymph node metastases amon g premenopausal Stage I and II breast cancer patients, and with increased e xpression of progesterone and estrogen receptors among postmenopausal ones. These results provide new insights into our understanding of the mechanism s of action of tea polyphenols and green tea extract as a cancer preventive .