Isoflavonoid Constituents of Soybeans and Isolation of a New Acetyl Daidzin

Abstract

The flavonoid constituents of defatted soybeans were studied. Two kinds of new natural isoflavones and four kinds of isoflavones were isolated by rechromatography on silica gel and Sephadex LH-20 columns of ethyl acetate extracts.
One of the new isoflavones was identified as 6''-O-acetyl daidzin, C₂₃H₂₂O₁₀, by UV, IR, PMR and CMR, and the four kinds of isoflavones were also identified as daidzein, daidzin, genistein and genistin.
High performance liquid chromatography of the ethyl acetate and acetone extracts were carried out, and six main peaks corresponding to the six isoflavones were recognized.
Glycitein and glycitein-7-O-glucoside were not detected in the soybeans.