Seven legume extracts containing phytoestrogens were analyzed for estrogenic activity. Methanolextracts were prepared from soybean (
Glycine max L.), green bean (
Phaseolus vulgaris L.), alfalfasprout (
Medicago sativa L.), mung bean sprout (
Vigna radiata L.), kudzu root (
Pueraria lobata L.),and red clover blossom and red clover sprout (
Trifolium pratense L.). Extracts of kudzu root and redclover blossom showed significant competitive binding to estrogen receptor
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(ER
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). Estrogenic activitywas determined using an estrogen-dependent MCF-7 breast cancer cell proliferation assay. Kudzuroot, red clover blossom and sprout, mung bean sprout, and alfalfa sprout extracts displayed increasedcell proliferation above levels observed with estradiol. The pure estrogen antagonist, ICI 182,780,suppressed cell proliferation induced by the extracts, suggesting an ER-related signaling pathwaywas involved. The ER subtype-selective activities of legume extracts were examined using transientlytransfected human embryonic kidney (HEK 293) cells. All seven of the extracts exhibited preferentialagonist activity toward ER
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. Using HPLC to collect fractions and MCF-7 cell proliferation, the activecomponents in kudzu root extract were determined to be the isoflavones puerarin, daidzin, genistin,daidzein, and genistein. These results show that several legumes are a source of phytoestrogenswith high levels of estrogenic activity.Keywords: Legume; MCF-7; estrogen; flavonoid; isoflavonoid; phytoestrogens; estrogen receptor(
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and
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)