Contributions of major components to the antimutagenic effect of Hsian-tsao (Mesona procumbens Hemsl.)

Our aim was to determine the antimutagenic activity of various solvent extr acts from an herb Mesona procumbens Hemsl, normally called Hsian-tsao in Ch ina. We also investigated the relationships between the special components in the water extract of Hsian-tsao (WEHT) and the antimutagenic activity. I t was found that the extracts at 0-0.6 mg/plate from three solvents (water, methanol, and ethyl acetate) exhibited a dose-dependent antimutagenic effe ct against benzo[a]pyrene [B(a)P] and 2-amino-3-methylimidazo(4,5-f)quinoli ne (IQ), both are indirect mutagens in Salmonella tester strains TA98 and T A100. The WEHT from three different plantations revealed a similar inhibito ry effect on the mutagenicity of IQ in TA 98 at 2.5-5.0 mg/plate. The inhib itory effect of WEHT on the mutagenicity of IQ correlates with their polyph enol and ascorbic acid contents but not with their chlorophyll contents. Th ese findings suggest that the antimutagenicity activity of WEHT may be attr ibuted mainly to their polyphenolic compounds and ascorbic acid.