霍山铁皮石斛多糖的脱蛋白工艺及结构分析

优选霍山铁皮石斛多糖脱蛋白工艺,并对其进行分离纯化及结构分析。以蛋白脱除率和多糖损失率为评价指标,比较Sevag法、酶法及酶-Sevag法3种脱蛋白方法。结果表明,酶-Sevag法脱蛋白效果最佳,蛋白脱除率为81.58%,多糖损失率为15.63%。采用DEAE-52纤维素柱、Sephadex G-100凝胶柱分离纯化石斛多糖,得活性组分DOPA-1;采用紫外扫描光谱、高效液相色谱鉴定DOPA-1为均一多糖;采用气相色谱分析表明组分单糖由甘露糖、葡萄糖和半乳糖组成(各单糖的物质的量比为1∶0.42∶0.27);采用红外光谱和刚果红实验分析糖链结构表明,DOPA-1有典型的糖类特征吸收峰,存在β-D-甘露吡喃糖苷,且具有三股螺旋构象。

Deproteinization and Structural Analysis of Polysaccharides from Dendrobium officinale Kimura et Migo Grown in Huoshan

In this study, the deproteinization and structural characterization of the polysaccharides extracted from Dendrobium officinale Kimura et Migo grown in Huoshan county of Anhui province were investigated. Three protein removal methods: the Sevage method, enzymatic hydrolysis and their combination were comparatively evaluated in terms of protein removal and polysaccharide loss rates. The combined method was found to have the highest deproteinization efficiency, yielding 81.58% protein removal and 15.63% polysaccharide loss. After purification of the polysaccharides by successive DEAE-cellulose-52 and Sephadex G-100 column chromatography, an active fraction named as DOPA-1 was obtained. By using UV spectroscopy and high performance liquid chromatography (HPLC), the polysaccharide DOPA-1 was confirmed to be homogeneous. Moreover, DOPA-1 was mainly composed of mannose, glucose and galactose as revealed by GC analysis, with a molar ratio of 1:0.42:0.27. IR spectroscopy and Cango red test indicated that DOPA-1 contained β-D-mannopyranose and possessed a triple-helix conformation.