Requirement of Metabolic Activation for Estrogenic Activity of Pueraria Mirifica

A wide range of chemicals derived from plant and human-made xenobiotics are reported to have hormonal activities. The present study was performed to examine the estrogenic effect of Kwao Keur, Pueraria mirifica (PM), that has been used as a rejuvenating folk medicine in Thailand, using recombinant yeast, MCF-7 cell proliferation and HepG2 cell transient transfection assay. In recombinant yeast assay, 0.025, 0.25, 2.5, 25,2.5 102, 2.5 103, 2.5 104 ng/ml concentrations of PM did not show any estrogenic activities, while 10-9 of 17-estradiol (positive control) showed high estrogenic activity. Estrogenic activities were induced at 2.5ng/ml to 25/ml concentrations of PM in a dose-dependent manner on MCF-7 cells and the estrogenic effect of PM was blocked by tamoxifen treatment, a well-known anti-estrogen. PM also showed estrogenic effect on human hepatoma cell line, HepG2 cells, containing estrogen receptor and luciferase reporter gene. Taken together, PM in itself may have no estrogenicity in yeast system, but it has estrogenicity in MCF-7 & HepG2 cells that have human metabolic enzymes. The results indicated that PM may require metabolic activation for estrogenic activity.

The enlarged underground tuber accumulates phytoestrogens comprising isoflavones such as daidzin, daidzein, genistin, genistein and puerarin. Recent studies have evaluated estrogenic activity of the isolated phytoestrogens from Pueraria mirifica (PM) such as kwakhurin, miroestrol, and deoxymiroestrol in MCF-7 human breast cancer cells.

Y.S. Lee1, J.S. Park1, S.D. Cho1, J.K. Son2, W. Cherdshewasart3 and K.S. Kang1*
Department of Veterinary Public Health, College of Veterinary Medicine, Seoul National University, San 56-1, Shilim-dong, Kwanak-gu, Seoul 151-742, Korea.
R&D Center of Household Products & Personal Care, Shinheung-dong 3ga 51-1, Jung-gu, Incheon, Korea
Department of Biology, Faculty of Science, Chulalongkorn University, Phyathai Road, Bangkok 10330, Thailland

Full Research (PDF): Click here