Analysis of Hydrolysis Products of Flavone Glycosides of Radix Astragali Using High Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry

The results analyzed using LC-MS indicated that, the main flavonoids contained in Radix Astragali are flavone beta-glycosides including calycosin-7-O-beta-D-glucoside, ononion, 9,10-di-methoxypterocarpan-3-O-beta-D-glucoside and 2'-dihydroxy-3', 4'-dimethyl-isoflavan-7-O-beta-D-glucoside. beta-glucosidase was chosen for the hydrolysis of flavone glycosides in Radix Astragali, which effciently converted the flavone glycosides into aglycones including calycosin, formononetin, 3-hydroxy-9, 10-di-methoxypterocarpan and 7, 2'-dlhydroxy-3',4'-dimethylisoflavan according to the LC-MS results. The hydrolysis rate of the flavone glycosides by beta-glucosidase was over 90%. The antioxidant activity of the hydrolyzed product of radix astragali was increased greatly through enzyme treatment which was almost 1.4 times comparing with that of the flavonoid extract without treatment.