Isolation and Identification by use of High Performance Liquid Chromatography of Isoflavone Compounds from Isoybeans

Abstract

The separation of isoflavones by high performance liquid chromatography (HPLC) was studied. HPLC of daidzin, genistin, daidzein and genistein were performed by the reversed phase method with a linear gradient elution with methanol (40-90%) on TSK-GEL, LS-410 as a stationary phase. The method was applied to the determination of isoflavones in soybeans. Defatted soybeans were extracted with ethanol, and the ethanol extract was treated with acetone and ethyl acetate. The ethyl acetate fraction was fractionated by silica gel and Sephadex LH-20 column chromatography. Main six peaks separated by HPLC of the acetone and ethyl acetate extracts were recognized as daidzin, genistin, 6″-O-acetyl daidzin, daidzein, 6″-O-acetyl genistin and genistein, respectively.