黄芪多糖分离与结构特征分析

Isolation and Structure Feature Analysis of Astragalus Polysaccharides

目的从黄芪中提取分离多糖并对其进行理化性质及结构特征分析。方法采用DEAE-52和Sephadex G-100色谱柱分离纯化,得到黄芪均一多糖APS-Ⅰ和APS-Ⅱ,通过高效液相色谱(HPLC)、红外光谱(IR)和环境扫描电镜(ESEM)对APS-Ⅰ和APS-Ⅱ进行结构及形貌特征分析。结果 APS-Ⅰ和APS-Ⅱ为均一多糖,APS-Ⅰ中单糖组成为甘露糖、鼠李糖、葡萄糖醛酸、半乳糖醛酸、葡萄糖和半乳糖,且摩尔比率为29.12∶1.89∶4.00∶1.35∶1∶81.97;APS-Ⅱ中单糖组成为甘露糖、鼠李糖、葡萄糖醛酸、半乳糖醛酸、葡萄糖、半乳糖和木糖,且摩尔比率为50.46∶1.16∶1∶2.27∶2.66∶15.72∶7.86。IR显示APS-Ⅰ和APS-Ⅱ均为酸性多糖。ESEM观察显示APS-Ⅰ形貌工整,APS-Ⅱ形貌不规则。结论 APS-Ⅰ是一种呈丝带状结构分子量约为1.06×104Da的杂多糖,APS-Ⅱ是一种分子量约为2.47×106Da的杂多糖。

Objective To extract and isolation Astragalus polysaccharides （APS） and to analyze the feature of their physicochem- istry and structure. Methods Two homogeneous polysaccharides,APS -Ⅰ and APS -Ⅱ ,were obtained by DEAE -52 and Seph- adex G - 100 column. IR spectrometry, High Performance Liquid Chromatography （ HPLC ） , and environmental scanning electron microscope （ESEM） were used to determine the structural and morphological properties. Results APS -Ⅰ and APS -Ⅱ were homogeneous polysaccharides. APS -Ⅰ contained six kinds of monosaccharides （ Man, RHA, GlcUA, GalUA, Glc, Gal） , and their molar ratios were 29.12： 1.89： 4.00： 1.35： 1 ： 81.97. APS -Ⅱ contained seven kinds of monosaccharides （ Man,RHA,G1-cUA,GalUA,Glc,Gal,Xyl） ,and their molar ratios were 50.46： 1.16： 1 ： 2.27： 2.66： 15.72： 7.86. The IR results revealed that APS - I and APS -Ⅱ were acidic polysaccharides. ESEM showed that APS -Ⅰ was neat and orderly, APS - Ⅱ had irregular structure. Conclusion APS -Ⅰ was heteropolysaecbaride and had ribbon structure,whose molecular weight was 1.06 × 106 Da, APS-Ⅱ was heteropolysaccharide ,whose molecular weight was 2.47 × 106 Da.