归芪多糖AAP-2A的结构特征研究  

Structural characterization of Guiqi polysaccharides AAP-2A

作　　者：蒲秀瑛[1] 马小龙[1] 刘璐[1] 任菁[1] 樊文博[1] 张伟杰[1] 李晓玥[1] 李海兵[1] 

机构地区：[1]兰州理工大学生命科学与工程学院,甘肃兰州730050

出　　处：《中草药》2015年第18期2689-2695,共7页Chinese Traditional and Herbal Drugs

基　　金：国家自然科学基金资助项目(81260070)

摘　　要：目的分离纯化归芪多糖AAP-2A,并对其结构特征进行研究。方法采用水提醇沉法提取归芪多糖(AAP),通过Sevag法脱除蛋白,DEAE-52纤维素柱色谱,葡聚糖凝胶柱色谱纯化等手段,得到1种新的归芪多糖AAP-2A。使用苯酚硫酸法测定了AAP-2A的含糖量,色谱技术检测了多糖紫外及红外性质、相对分子质量、绝对分子质量、分子构象及相对分子质量分布、单糖组成及其摩尔比值等特征。采用甲基化法和NMR法研究了AAP-2A的连接方式、主链和支链结构及分支点特征。结果 AAP-2A总糖量为98.98%,且不含核酸及蛋白质,红外吸收光谱分析表明AAP-2A有明显的多糖特征吸收,AAP-2A的相对分子质量大于6.68×105,绝对分子质量为2.252×106,由鼠李糖、半乳糖、阿拉伯糖、葡萄糖组成,其物质的量比依次为1∶2.13∶3.22∶6.18。主链骨架由1,3-α-L-鼠李糖,1,3-β-D-半乳糖,1,3、1,5、1,3,5-α-L-阿拉伯糖和1,4、1,4,6-α-D-葡萄糖组成,侧链分支点位于阿拉伯糖的3位和葡萄糖的4位,侧链分支由1位连接的α-D-葡萄糖组成。结论AAP-2A为一种新的中性归芪杂多糖,其构象呈高度支化状。Objective To isolate the Guiqi（Angelicae Sinensis Radix and Astragali Radix） polysaccharides（AAP） and study the structural characterization of AAP-2A. Methods Hot water extracting and ethanol precipitating method was employed to isolate the AAP. A new fraction（AAP-2A） of AAP was obtained after AAP was purified by deproteination, gel chromatography on DEAE-52 cellulose, gel chromatography on Sephadex G-100, and other means. Sugar content of AAP-2A was determined using phenol sulfuric acid method. Chromatography techniques were used to determine the ultraviolet properties, infrared properties, relative molecular weight, absolute molecular weight, molecular conformation and molecular weight distribution, and monosaccharide composition with the molar ratio of AAP-2A. The connection, main chain and branched-chain structures, and the condition of branching point were studied by methylation and NMR methods. Results The total sugar content of AAP-2A, which was absent of proteins and nucleic acids, was 98.98%. Infrared spectroscopy showed that AAP-2A had the typical signals of polysaccharides. The relative and absolute molecular weights of AAP-2A were above 6.68 × 10^5 and 2.252 × 10^6; AAP-2A was a neutral sugar and composed of rhamnose（Rha）, galactose（Gal）, arabinose（Ara）, and glucose（Glc） with a molar ratio of 1 ： 2.13 ： 3.22 ： 6.18. AAP-2A proved to be a heteropolysaccharide, with 1, 3-α-L-Rha, 1,3-β-D-Gal, 1,3-, 1,5-, and 1,3,5-α-L-Ara, 1,4- and 1,4,6-α-D-Glc residues in backbone and 1-α-D-Glcp residues in branches. Conclusion AAP-2A is a new neutral heteropolysaccharide from Guiqi polysaccharides with a highly branched conformation.

关 键 词：当归 黄芪 归芪多糖 中性多糖 结构特征 

分 类 号：R284.18[医药卫生—中药学]