[Preparation of soybean isoflavone glucosides by reversed-phase high performance liquid chromatography]

A method was established for the isolation of soybean isoflavone glucosides from the total isoflavone extracts of soybean using preparative reversed-phase high performance liquid chromatography (RP-HPLC). The total isoflavone extracts were separated into four parts by solvent extraction, those are the ethyl acetate extract, butanol extract, precipitate (D4), and the remaining aqueous phase. The part D4 containing soybean isoflavone glucosides was acquired and subjected to preparative HPLC for the isolation of target components. A preparative Nova-Pak HR C18 column (100 mm x 25 mm i. d. , 6 microm) was used in the preparation process. By isocratic elution with methanol-0.1% aqueous acetic acid (23:77, v/v) as the mobile phase at a flow rate of 20 mL/min, followed by concentration and desalination, three soybean isoflavone glucosides were obtained and subsequently identified by mass spectrometry as daidzin, glycitin, and genistin. HPLC analysis showed that the purities of the three soybean isoflavone glucosides were all higher than 99%.