Effect of Coffee on the Mutagenicity of Beef Extracts in the Salmonella/Microsome

Water extracts of roasted coffee beans (WEC) were examined for antimutagenic activity with Salmonella typhimurium test strain, TA 98. These water extracts significantly decreased the reverse mutation induced by crude dimethylsulfoxide extracts of grilled beef (DEGB) in the presence of a rat liver microsomal activation system. When DEGB was pretreated with WEC beforehand, its mutagenicity was gradually decreased with elongation of pretreatment period. Conversely, WEC was not found to inhibit the mutagenicity induced by AF2 in the absence of microsomal activation system. The addition of WEC to the reaction mixture at the initiation of inhibition test protected the desappearance of the mutagenicity of AF2 by metabolic enzyme reactions to some extent.