Characterization of Soybean Germinated Embryo Extract as an Estrogen Receptor Subtype-Selective and Tissue-Specific Modulator

Abstract

Phytoestrogens possess beneficial effects in the management of menopausal symptoms with few side effects. Soybeans are major natural sources of isoflavones, with high estrogen receptor (ER)-beta selectivity. The objective of this study therefore was to develop a solvent-mediated extraction method for soybean germinated embryos (SGEs) and to investigate the biological activities of the extract. Ethanolic extraction yielded the SGE extract (SGEE), which had a unique composition of biologically active aglycones and soyasaponins. SGEE showed a proliferative effect in MCF7 cells and ER beta-selective transcriptional activities in human embryonic kidney cells. In addition, oral administration of SGEE to ovariectomized rats resulted in the induction of ER beta and estrogen-responsive genes in the uterus and a decrease in tail skin temperature and uterus weight. Our data suggest that germination and ethanolic extraction are effective measures for producing isoflavone-rich food supplements, which may be useful as alternative menopausal hormone therapy.