Pueraria mirifica (PM) has been interested because of phytoestrogens contained in its roots, showing female hormone like effects. From the study of non-human primate, Macaca fascicularis, after a single feeding of 1,000 mg of PM (PM-1,000), the length of menstrual cycles were prolonged in adult monkeys, but the doses of 10 and 100 mg of PM (PM-10 and PM-100) could not change menstrual cycle lengths. The serum patterns of follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2), or progesterone (P) in all two entire menstrual cycles did not change in all monkeys after treatment with PM-10, PM-100, or PM-1,000, when compared with those of pre-treatment. In the study of daily treatment of PM-10, PM-100, or PM-1,000, the menstrual cycle lengths were prolonged significantly during PM-10 and PM-100 treatments, and stopped completely throughout the PM-1,000 treatment and post-treatment periods. Serum FSH, LH, E2, and P levels were suppressed during treatment in a dose-dependent manner. During the post-treatment period, changes of menstrual cycle length and suppressed hormonal levels could recover in PM-10 and PM-100 groups, but could not recover in PM-1,000 group. Similarly, serum FSH, LH, and E2 levels were also suppressed in aged menopausal monkeys treated with PM-10, PM-100, and PM-1,000 for 90 days. From these results, it was assumed that phytoestrogens contained in PM acted as estrogen and suppressed the hypothalamus and/or pituitary functions by reducing the secretion of GnRH, FSH, and LH, then suppressed the secretion of sex steroid hormones in both adult and aged monkeys. In conclusion, PM influence reproduction by estrogenic action of phytoestrogens.
