铁皮石斛多糖的分离纯化及其结构研究

Isolation,purification,and chemical composition analysis of polysaccharides from Dendrobium officinale

采用DEAE-52阴离子交换柱色谱法以及Sephadex G-100凝胶柱色谱法对铁皮石斛粗多糖进行分离纯化,得到4个不同相对分子质量(Mw)纯多糖组分(DOP1、DOP2、DOP3和DOP4)。运用柱前衍生化高效液相色谱法、凝胶渗透色谱(GPC)法和傅立叶红外光谱对其单糖组成、纯度和相对分子质量以及结构中单糖连接方式进行分析。研究结果表明:分离得到的4种铁皮石斛多糖的GPC色谱图均呈现为单一狭窄的对称峰,表明多糖纯度很高且均一性很好。单糖组成测定结果显示其主要为D-甘露糖和D-葡萄糖组成杂多糖,但D-甘露糖和D-葡萄糖的摩尔比在4种多糖中有一定差异性。红外光谱结果表明这四个多糖均为β-构型为主的酸性吡喃糖。研究结果可为今后铁皮石斛多糖活性和构效关系的研究奠定基础。

Crude polysaccharide from Dendrobium officinale was successively isolated and purified by DEAE-52 cellulose anion-exchangechromatography and Sephadex G-100 gel-permeation chromatography and four polysaccharides named DOP1,DOP2,DOP3 and DOP4were obtained with different molecular weights（ Mw）,respectively. Subsequently,the chemical composition of four polysaccharides,the purity and molecular weight of polysaccharides,and the interlinking style of monosaccharide in the molecular structure were determined by high-performance liquid chromatography with precolumn derivatization,gel permeation chromatography（ GPC）,and fourier transform infrared spectrometry method. GPC analysis indicated that the polysaccharides were homogeneous with a singlesymmetrical peak. Monosaccharide analysis showed that four polysaccharides were mainly composed of D-Man and D-Glc and demonstrated to be hetero-polysaccharide,while the mole ratios of D-Man and D-Glc in four polysaccharides were significantly different. The infrared spectrum analysis revealed that four polysaccharides were verified to be β-dominating configuration in acidic pyranose form sugars. The results of this workmay be useful for future study on the activity and structure-activity relationship of polysaccharides in Dendrobium officinale.