【摘要】 目的:天麻药材经提取分离及纯化得3个单一多糖成分,研究其第2组分(GEPⅡ)的物理性质和化学结构。方法:利用黏度法测定多糖GEPⅡ的分子量,旋光仪测定比旋光度,运用多糖酸水解、高碘酸氧化与Smith降解等化学分析方法及IR、GC、1H-NMR等作为检测手段,分析天麻多糖GEPⅡ的化学结构。结果:GEPⅡ为白色粉末状固体,水溶性强,水溶液呈透明粘稠状,pH弱酸性,平均分子量为2.92×103。经完全酸水解法、高碘酸氧化、Smith降解、碘反应、GC、IR、1H-NMR等分析表明:GEPⅡ由葡萄糖和甘露糖组成,且为α-D-Glu,β-D-Glu,α-Man,β-Man;GEPⅡ主要由α型糖苷键构成,少部分由β型构成,主要为1→6糖苷键,还含有1→4糖苷键,可能存在1→2糖苷键,不存在1→3糖苷键。结论:通过前述方法阐明了GEPⅡ的一级化学结构。更多还原

【Abstract】 OBJECTIVE To identify the chemical structure of a polysaccharideⅡisolated from Gastrodia elata Blume.METHODS Purified Gastrodia elata polysacharides were isolated and purified by Sephadex G-75 gel filitration.After using UV and Sephadex G-75 column chromatogram to identify the obtained polysaccharideⅡis homogeneous polysaccharide,then use total acid hydrolysis,periodate oxidation,smith degradation and chromatography spectroscopy such as IR,GC,1H-NMR to identify structure of polysaccharideⅡ.RESULTS Three obtained fractions were:GEPⅠ,GEPⅡ,GEPⅢ.Then GEPⅡ was determined in this experiment.GEPⅡ is white power.After being checked by UV showing no specific absorbability at 260nm,280nm,and by Sephadex G-75 column chromatogram showing a single symmetrical peak,it was proved to be homogeneous polysaccharide.Its average molecular weight is 2.92×103 by means of viscosimeter.Through completely hydrolysis with acid,periodate oxidation,I2 reaction,IR,G.C,1H-NMR analysis,they reveal that GEPⅡ is composed of Glc and Man,and they are β-D-Glu,α-andβ-Man.There are major α-configuration and minor β-configuration.There are 1→6 and 1→4 bonds,may exist 1→2 bonds,but there are no 1→3 bonds.CONCLUSION Through chemical and physical methods,the structure of GEPⅡ was illuminated.更多还原