对膜荚黄芪（Astragatus membranaceus (Fisch.)Bunge）的成分进行了系统分离和鉴定,同时用E- 112顺磁共振仪测定了以芒柄花素为代表的异黄酮类化合物清除超氧自由基的活性,结果证明黄芪中的异黄酮类化合物具有清除超氧阴离子的活性。这可能是黄芪药物具有治疗心力衰竭和抗衰老的活性机理之一,在分离过程中,得到15种结晶,经化学降解和光谱分析分别鉴定为:晶Ⅰ:蔗糖（sucrose）,晶Ⅱ:黄芪皂甙Ⅳ（astragaloside Ⅳ）,晶Ⅲ:芒柄花素（formononetin）,晶Ⅳ:毛蕊异黄酮（calycosin）,晶V:黄芪皂甙Ⅵ（astragaloside Ⅵ）,晶Ⅵ:（3R）7,2-二羟基-5’,6’二甲氧基异黄烷-7-O-β-D葡萄糖甙,晶Ⅶ:黄芪皂甙Ⅱ（astragaloside Ⅱ）,晶Ⅶ:黄芪皂甙Ⅱ（astragaloside Ⅱ）,晶Ⅷ:黄芪皂甙Ⅲ(astragaloside Ⅲ）,晶Ⅸ:β-谷甾醇（β-sitosterol),晶Ⅹ:棕榈酸（palmitic acid）,晶Ⅺ:胡萝卜甙（daucosterol),晶XⅡ～XV结构待定,本文主要报道晶Ⅲ的活性及晶Ⅵ的结构鉴定,晶Ⅵ为一新化合物。

The active constituents of Astragatus membranaceus (Fisch.)Bunge were isolated and identified, and the scavenging superoxide anion free radical activities of these constituents were detected by using Electron Paramagnetic Resonance. The experimental results showed that isoflavanoids of A. membranaceus possess the activities of scavenging superoxide anion. 'This is possibly one of the principles which hhs activities of antiaging and curing hedrt failure. In the process of isolation. we got 15 crystals. They were identified separately by chemical decomposition and spectra analysis. Crystal I : sucrose; CrystalⅡ : astragaloside Ⅳ ; Crystal Ⅲ : formononetin ; Crystal Ⅳ: calycosin ;CrystalⅤ : astragaloside Ⅵ ; Crystal VI : (3R) 7,2'-dihydroxy-5' .6-dimethoxy isoflavan-7-O-β-D ,glucoside; Crystal Ⅶ : astragaloside Ⅱ; Crystal Ⅷ : astragaloside Ⅲ ; Crystal Ⅸ :β-sitosterol; Crystal Ⅹ :palmitic acid; Crystal Ⅺ : daucosterol; Crystal X II - XV : the structures will be identified by studying further. This paper deals with the results of Crystal Ⅱscavenging superoxide anion and identification of Crystal Ⅵ. Crystal VI is a new structure.