高效液相色谱-电喷雾质谱联用测定黄芪黄酮苷酶解产物

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

高效液相色谱-电喷雾质谱(HPLC-ESI-MS)联用分析黄芪中的黄酮类化合物结果表明黄芪黄酮提取物主要包含毛蕊异黄酮-7-O-β-D-葡萄糖苷、芒柄花苷、9,10-二甲氧基紫檀烷-3-O-β-D-葡萄糖苷以及2′-羟基-3′,4′-二甲氧基异黄烷-7-O-β-D-葡萄糖苷等黄酮苷,黄芪黄酮提取物经过β-葡萄糖苷酶(1IU/mL)粗酶液酶解后,HPLC-ESI-MS分析酶解生成产物主要为黄酮苷元毛蕊异黄酮、芒柄花素、3-羟基-9,10-二甲氧基紫檀烷以及7,2′-二羟基-3′,4′-二甲氧基异黄烷。其中前两种主要的黄酮苷酶解率均达90%以上。酶解后所得产物对DPPH自由基清除率是酶解前的1.4倍。因此,通过β-葡萄糖苷酶水解可以有效地将黄芪黄酮转化为相应的黄酮苷元,大大提高黄芪黄酮提取物的抗氧化活性。

The results analyzed using LC-MS indicated that, the main flavonoids contained in Radix Astragali are flavone β-glycosides including calycosin-7-O-β-D-glucoside, ononion, 9, 10-di-methoxypterocarpan-3-O-β- D-glucoside and 2＇-dihydroxy-3＇,4＇-dimethyl-isoflavan-7-O-β-D-glucoside. β-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＇-dihydroxy-3＇,4＇- dimethylisoflavan according to the LC-MS results. The hydrolysis rate of the flavone glycosides by β-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.