Abstract:

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×25 mm i.d., 6 μm) 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%.

Key words:
soybean , glucosides, soybean isoflavones, preparative high performance liquid chromatography