TEA POLYPHENOLS AS INHIBITORS OF MUTAGENICITY OF MAJOR CLASSES OF CARCINOGENS

Previous research suggested that the mutagenicity of some genotoxic ca rcinogens, mainly heterocyclic amines, was decreased by green or black tea extracts, or tea polyphenol fractions. Thus, it seemed important to test a variety of genotoxic carcinogens with distinct chemical stru ctures and means of biochemical activation as regards modification of mutagenicity in appropriate strains of Salmonella typhimurium by 3 con centrations of polyphenols 60, 100, or B, standard commercial polyphen ol preparations from green or black tea. Polyphenols sharply decreased the mutagenicity of a number of aryl- and heterocyclic amines, of afl atoxin B-1, benzo[a]pyrene, 1,2-dibromoethane, and more selectively, o f 2-nitropropane, all involving an induced rat liver Sg fraction. Good inhibition was found with 2 nitrosamines that required a hamster S9 f raction for biochemical activation. No effect was found with 1-nitropy rene, and with the direct-acting (no S9) 2-chloro-4-methylthiobutanoic acid. Thus, with some exceptions, polyphenols considerably decreased the mutagenicity of diverse types of carcinogens.