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Indexed/Abstracted in: EMBASE, Science Citation Index Expanded (SciSearch), Scopus
Impact Factor 0,246
Online ISSN 1827-160X
MEDICINAL PLANTS FOR BIOTECHNOLOGY AND BIOMEDICINE
Department of Experimental Pathology, University of Bologna, Bologna, Italy
Green tea contains active polyphenols called catechins, thought to have beneficial effects on human health including a chemo-preventive action. The present review will summarize epidemiologic in vivo and in vitro studies that support this hypothesis. Epidemiologic studies, mostly conducted in Asia, demonstrated green tea had a chemo-preventive effect on prostate, ovary and breast cancer. In contrast, conflicting data have been published about gastrointestinal, lung and bladder cancer. Before achieving conclusive evidences, similar studies need to be also undertaken in Western countries and evaluated taking into an account of differences in genetic background, exposure to environmental agents, alimentation and style of life. In animals, where these differences are limited, there is general agreement that green tea catechins were able to limit and delay tumor development in many organs and tissues (oral mucosa, esophagus, stomach, intestine, pancreas, liver, bladder, lung and breast) after exposure to numerous carcinogens. Green tea catechins were also demonstrated to reduce metastasis development after cancer cells inoculation in animals (nude and nonobese diabetic/severe combined immunodeficient NOD/SCID mice) or in animal models spontaneously developing metastasis. In vitro studies demonstrated that green tea catechins selectively killed cancer cells at doses comparable to those present in the human body of a usual drinker. Although the molecular targets of green tea catechins are far to be fully disclosed, NF-kB, p53, PI3K/Akt, EGF/Her-2 pathways and downstream molecules involved in cell cycle, apoptosis, adhesion, invasion, angiogenesis and metastasis have been demonstrated to be affected by EGCG treatment. Green tea is cheap, widely diffuse and has a few toxic side-effects: these characteristics and the evidences so far achieved make it as an ideal candidate for studies aimed to better define its anti-cancer action, for a rational use in human health.