Inhibitory Effect of Coffee Extract against Some Mutagens

The effects of coffee extracts on mutagenicity were studied using the Salmonella typhimurium system. Coffee extracts showed inhibitory effects on the mutagenicity of such mutagens as 3-amino-l-methyl-5H-pyrido[4,3–b]indole (Trp-p-2), 2-acetylaminofluorene (AAF), and benzo(a)pyrene (B(a)P), whose mutagenicity require metabolic activation by rat liver microsomal fraction, S-9 mix. The inhibition of mutagenicity increased in proportion to the level of roasting or to the darkness in color of the coffee extracts. When the coffee extracts were applied to a Sephadex G-50 column, two color pigment peaks were observed, the second peak showing the inhibitory activity towards mutagenicity. The inhibitory substance towards the mutagenicity was formed only in a heat-treated mixture of sucrose with either chlorogenic or caffeic acid, among various heat-treated combinations of components in raw coffee beans. The decrease of mutagenicity by coffee extracts was due to inhibiting the metabolic activation by S-9 mix.