Inhibition of mutagenicity by glycyrrhiza extract and glycyrrhizin.

The effects of Glycyrrhiza extract and one of its components, glycyrrhizin, on the mutagenicities of several mutagens were investigated by means of a modification of the Ames' test. Both inhibited the mutagenicities of 3-amino-1,4-dimethyl-5 H-pyrido[4,3-b]-indole (Trp-P-1) and 3-amino-1-methyl-5 H-pyrido[4,3-b]indole. Since the Glycyrrhiza extract and glycyrrhizin inhibited the mutagenicity of activated Trp-P-1, it was clear that their inhibitory effects were not due to inhibition of the enzyme activity of the S9 fraction. Both Glycyrrhiza extract and glycyrrhizin also inhibited the mutagenicities of benzo[a]pyrene, 3-methylcholanthrene, 2-naphthylamine, 2-amino-6-methyldipyrido[1,2-a:3',2'-d]-imidazole, dimethylnitrosoamine and dimethylaminoazobenzene. The mutagenicity of 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2) was inhibited by the Glycyrrhiza extract but not by glycyrrhizin. This suggested that a component different from glycyrrhizin, present in the Glycyrrhiza extract, inhibited the mutagenicity of AF-2.