Estrogenic Effects of the Extracts from the Chinese Yam (Dioscorea opposite Thunb.) and Its Effective Compounds in Vitro and in Vivo.

BACKGROUND The aim of this study was to explore the estrogenic effects of the extracts from Chinese yam and its effective compounds. METHODS The activity of the yam was investigated by the uterine weight gain of mice and a proliferation assay of breast cancer cell lines (MCF-7 cell); the estrogenic activity was comprehensively evaluated by a serum pharmacology experiment. The levels of estradiol (E2), follicle stimulating hormone (FSH), and luteinizing hormone (LH) were also measured. Western blot analysis and antagonist assays with faslodex (ICI182,780), methylpiperidino-pyrazole (MPP), Delta (9) -tetrahydrocannabinol (THC), and G-15 were used to explore the mechanism of the effects of the yam. To find the effective compounds of the yam which play a role in its estrogen-like effects, we used the same methods to study the effects of adenosine and arbutin. RESULTS The Chinese yam and two main compounds, adenosine and arbutin, have estrogen-like effects. The mechanism of the yam which plays a role in its estrogen-like effects was mainly mediated by the estrogen receptors ERα, ERβ, and GPR30; that of adenosine was mainly mediated by estrogen receptors ERα and ERβ, and that of arbutin was mainly mediated by estrogen receptors ERβ and GPR30. CONCLUSIONS The Chinese yam has estrogen-like effects; adenosine and arbutin are two of the effective compounds in the yam which play a role in its estrogen-like effects.