Antioxidant Reactions of Green Tea Catechins and Soy Isoflavones
Green tea, a popular beverage brewed from dried leaves of the tea bush (Camellia sinensis) is distinguished by the presence of a group of polyphenols called flavanols or catechins (Graham, 1992). In recent years, the principal green tea catechins, i.e. (-)-epicatechin, (-)-epicatechin-3-gallate, (-)-epigallocatechin (EGC), and (-)-epigallocatechin-3-gallate (EGCG) have been recognized to be effective protectants against certain forms of cancer (Katiyar et al., 1992; Yang et al., 1993). These protective effects often have been attributed to antioxidant actions (Jovanovic et al., 1994; Terao et al., 1994; Salah et al., 1995; Kondo et al., 1999). The potential role of soy products in cancer prevention also has received much attention in recent years. Epidemiological data indicate that consumption of soybean-containing diets is associated with a lower incidence of certain human cancers in Asian compared to Caucasian populations (King et al., 1980; Locke et al., 1980). Genistein is one of the two principal isoflavones found in soy (Murphy, 1982) and, like catechins, is thought to act in large part through its ability to scavenge oxidants involved in carcinogenesis (Wei et al., 1993).
KeywordsPeroxyl Radical Epigallocatechin Gallate Phenoxyl Radical Epicatechin Gallate Antioxidant Reaction
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