Tannins, xenobiotic metabolism and cancer chemoprevention in experimental animals

Tannins are plant polyphenolic compounds that are contained in large quanti ties in food and beverages (tea, red wine, nuts, etc.) consumed by humans d aily. It has been shown that various tannins exert broad cancer chemoprotec tive activity in a number of animal models. This review summarizes the rece nt literature regarding both the mechanisms involved, and the specific orga n cancer models used in laboratory animals. An increasing body of evidence demonstrates that tannins act as both anti-initiating and antipromoting age nts. In view of the fact that tannins may be of valid medicinal efficacy in human clinical trials, the present review attempts to integrate results fr om animal studies, and considers their possible application in humans.