Green tea and cancer chemoprevention

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 gree n tea; the others are (-)-epicatechin gallate, (-)-epigallocatechin and (-) -epicatechin (EC). This paper reports the results of our latest pharmacolog ical and biochemical studies with H-3-EGCG, along with studies on human sub jects. The study on bioavailability of H-3-EGCG in mice revealed the wide d istribution of radioactivity in multiple organs. Specifically, radioactivit y was found in all reported target organs of EGCG and green tea extract (di gestive tract, Liver, lung, pancreas, mammary gland and skin) as well as ot her organs (brain, kidney, uterus and ovary or testes) in mice. Recently, w e demonstrated that EC enhanced incorporation of H-3-EGCG into human lung c ancer cell line PC-9 cells. EC along with another cancer preventive agent s ulindac also synergistically enhanced apoptosis in PC-9 cells induced by EG CG. Moreover, 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 consumpti on of green tea is a practical and effective cancer preventive both before cancer onset and after cancer treatment. (C) 1999 Elsevier Science B.V. All rights reserved.