Cancer Chemoprevention: Tea Polyphenol Induced Cellular and Molecular Responses.

Considerable evidence is now available showing that tea infusions can prevent tumor induction in experimental animals by a variety of chemical carcinogens. Such an action is mainly attributed to the polyphenolic constituets of tea. These polyphenols possess antioxidant activity and interfere with carcinogen activation, show anti-mutagenic and anti-genotoxic properties, exhibit anti-tumor promoting activity and alter certain events in signal transduction pathways. Tea polyphenols are known to exhibit cytotoxicity towards various human tumor cell lines as well as growth inhibition that is accompanied by cell cycle arrest. It has been demonstrated that the cytotoxicity result in inducton of apoptosis. Additionally, tea polyphenols are good candidates for sensitizing tumor cells leading to apoptotic death by cytotoxic drugs.