Variance of estrogenic activity of the phytoestrogen-rich plant

Objective: To evaluate the influences of seasonal changes and plant cultivars on estrogenic activity of the phytoestrogen-rich plant, Pueraria mirifica. Methods: Three cultivars of P mirifica; PM-I, PM-II and PM-V, were grown in the same field trial for 3 years and random tubers collected during the summer, rainy season and winter seasons. Female Wistar rats were ovariectomized, kept for 14 clays, randomly segregated into groups and treated with one of DW, 200 mu g/100g BW 17 beta-estradiol (E2) or tuberous powder of PM-I, PM-II and PM-V at dosages of 100, or 1000 mg/kg BW for the next 14 days. For the last 7 days of post-treatment period, rats received only DW. The vaginal cornification was recorded during the treatment and post-treatment period. The uterine tissues of the treated rats at the treatment and post-treatment periods were analyzed for uterine gland number and for the surface area of the myometrium, endometrium and lumen. In addition, ethanol tuberous extracts of PM-I, PM-II and PM-V was submitted to DPPH analysis. Results: Vaginal cornification exhibited a dose-dependent response with plant samples collected during the winter and summer being more active than those collected in the rainy season. All plant samples-induced uterotrophic effects in the analysis at the treatment and post-treatment periods in a dose-dependent manner. The P mirifca treated rats exhibited increasing uterine gland numbers and thickness of the endometrium and myometrium but a decreasing size of lumen, in Comparison to the negative control. The results were more prominent in PM-I than other plants and also in plant samples collected during the winter and summer seasons than in the rainy season. DPPH assay of the ethanol tuberous extracts revealed variance in antioxidant activity. Conclusion: The results of uterotrophic and vaginal cornification assays reveal that P mirifica exhibits a dose-dependent estrogenic activity under the influence of both seasonal changes and plant cultivars, which is confirmed by DPPH assay. (C) 2008 Elsevier Ireland Ltd. All rights reserved.