Effects of nine active ingredients in Chinese herbal medicine sho-saiko-to on 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide mutagenicity

The antimutagenic effects of nine active compounds in the Chinese herbal medicine ''sho-saiko-to'' on mutagenesis induced by a direct-acting mutagen, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2) were investigated in Salmonella typhimurium, strain TA100. The active compounds examined were classified into two major groups, saponins and flavonoids, the former comprising glycyrrhizin, saikosaponins a, c and d, and ginsenosides Rb1 and Rg1, and the latter, baicalin, balcalein and wogonin. Saikosaponin a and ginsenoside Rbl were found to reduce the mutagenicity of AF-2 significantly when applied post-AF-2-treatment in the Salmonella mutagenicity assay. Ginsenoside Rbl also decreased the mutagenic activity of AF-2 in a simultaneous treatment protocol. The results indicate that saikosaponin a and ginsenoside Rbl may enhance DNA repair, and ginsenoside Rbl may also have the ability to inactivate the mutagenic activity of AF-2 directly. On the other hand, saikosaponin d and baicalin showed a slight enhancing effect. None of the compounds, except baicalein, showed any toxic effect on the test strain. These findings may be useful for the development of chemopreventive agents.