"Pueraria mirifica is a Thai phytoestrogen-rich herb traditionally used for the treatment of menopausal symptoms. Pueraria lobata is also a phytoestrogen-rich herb traditionally used in Japan, Korea and China for the treatment of hypertension and alcoholism," scientists in Bangkok, Thailand report (see also Life Sciences).

"We evaluated the mutagenic and antimutagenic activity of the two plant extracts using the Ames test preincubation method plus or minus the rat liver mixture S9 for metabolic activation using Salmonella typhimurium strains TA98 and TA100 as indicator strains. The cytotoxicity of the two extracts to the two S. typhimurium indicators was evaluated before the mutagenic and antimutagenic tests. Both extracts at a final concentration of 2.5, 5, 10, or 20 mg/plate exhibited only mild cytotoxic effects. The plant extracts at the concentrations of 2.5, 5 and 10 mg/plate in the presence and absence of the S9 mixture were negative in the mutagenic Ames test. In contrast, both extracts were positive in the antimutagenic Ames test towards either one or both of the tested mutagens 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide and benzo(a) pyrene. The absence of mutagenic and the presence of anti-mutagenic activities of the two plant extracts were confirmed in rec-assays and further supported by a micronucleus test where both plant extracts at doses up to 300 mg/kg body weight (equivalent to 16 g/kg body weight plant tuberous powder) failed to exhibit significant micronucleus formation in rats," wrote W. Cherdshewasart and colleagues, Chulalongkorn University.

The researchers concluded: "The tests confirmed the non-mutagenic but reasonably antimutagenic activities of the two plant extracts, supporting their current use as safe dietary supplements and cosmetics."

Cherdshewasart and colleagues published their study in Brazilian Journal of Medical and Biological Research (The mutagenic and antimutagenic effects of the traditional phytoestrogen-rich herbs, Pueraria mirifica and Pueraria lobata. Brazilian Journal of Medical and Biological Research, 2009;42(9):816-823).

For more information, contact W. Cherdshewasart, Chulalongkorn University, Faculty Science, Dept. of Biology, Phyathai Rd., Bangkok 10330, Thailand.

Publisher contact information for the Brazilian Journal of Medical and Biological Research is: Association Bras Divulg Cientifica, Faculdade Medicina, Sala 21, 14049 Ribeirao Preto, Sao Paulo, Brazil.