Phytoestrogen constituents and estrogenic activity of Pueraria candollei var. mirifica callus and its extract preparation for removing cytotoxic constituents

In vitro cultures of Pueraria candollei var. mirifica (PC) are a promising source of phytoestrogens, however, the estrogenic activity of PC callus has not been evaluated. In this study, the phytochemicals of PC callus were analyzed and compared with the estrogenic activities on MCF-7 cell proliferation. The ethanolic extract of PC callus contained isoflavonoids and deoxymiroestrol. The estrogenic activity of the extract (10 µg/mL) was equivalent to 1×10-10 M estradiol. When the crude extract was reconstituted with 10% (v/v) ethanol in water, most of the isoflavonoid and deoxymiroestrol contents were solubilized. The soluble fraction exhibited the estrogenic effect in a concentration-dependent manner, but treatment with the insoluble fraction at a high concentration (100 µg/mL) resulted in cell growth suppression. Overall, the crude ethanolic extract and 10 %(v/v) ethanol-soluble crude extract of PC callus were good sources of phytoestrogens. The reconstitution could remove toxic constituents, but the estrogenic activity was retained