The Biochemistry of Green Tea Polyphenols and Their Potential Application in Human Skin Cancer

Green tea contains many polyphenol substances with exceptional antioxidant activity, and is consumed widely throughout the world. Green tea aqueous extract and its polyphenols, of which epigallocatechin gallate (EGCG) predominates, have been studied extensively in animal models for their anti-neoplastic properties. EGCG and green tea polyphenols (GTP) have been shown to inhibit skin tumor initiation, promotion, and progression by a number of mechanisms, including, but not limited to: inhibition of DNA binding by carcinogens, radical scavenging, inhibition of cytochrome P-450, maintenance of cellular communication, and inhibition of arachidonic acid metabolism. It is evident that the consumption of green tea is beneficial in the prevention of cancer in these models; however, the question remains whether use of oral or topical green tea preparations will have a preventative effect on human skin cancers, and should be answered by well-designed human clinical and epidemiological studies. (Alt Med Rev 1996;1:31-42.)