Abstract
Soy isoflavones have been identified as dietary components having an important role in reducing the incidence of breast and prostate cancers in Asian countries The isoflavone polyphenol genistein in soybean is considered to be a potent chemopreventive agent against cancer Several studies, both in vitro and in vivo, have clearly shown that genistein is a promising therapeutic candidate for cancer chemoprevention as it is able to cause inhibition of human cancer growth via pathways that lead to apoptotic cell death Genistein has pleiotropic molecular mechanisms of action affecting estrogen mediated signaling pathways, cell cycle regulation, apoptosis and cell growth signal cascades Of particular interest is the observation that genistein has been found to induce apoptosis in cancer cell lines but not in normal cells We have proposed a novel mechanism for the cytotoxic action of plant polyphenols including genistein, which has implications for its chemopreventive properties against cancer We believe that such a mechanism better explains the preferential cytotoxicity of genistein towards cancer cells In this review we discuss various mechanistic approaches that have been proposed to account for the chemopreventive properties of genistein