中文摘要：

目的研究铁皮石斛原球茎多糖的理化性质。方法经过水提醇沉、脱蛋白和透析等步骤获得铁皮石斛粗多糖（CDO）和原球茎粗多糖（CDOP）;CDOP经过纤维素DE-52和葡聚糖凝胶Sephadex G-200柱层析获得6个均一多糖;用高效凝胶渗透色谱法（HPGPC）测定均一多糖的纯度及相对分子质量;用气相色谱法（GC）分析粗多糖和均一多糖的单糖组成;用高碘酸氧化-Smith降解反应研究均一多糖的一级结构。结果 CDO主要由甘露糖和葡萄糖组成,物质的量比为4.29∶1.00;CDOP主要由半乳糖、阿拉伯糖和葡萄糖组成,物质的量比为2.80∶1.00∶0.61。从CDOP中获得了6个质量均一的多糖,分别为DOPW-1（78×103）、DOPW-2（37×103）、DOPS1-1（287×103）、DOPS1-2（351×103）、DOPS1-3（335×103）和DOPS1-4（171×103）;它们的单糖组成及物质的量比等特点与DOP的相同;各均一多糖分子中的1→3糖苷键均主要由半乳糖组成,还含有阿拉伯糖、葡萄糖和鼠李糖;除DOPS1-4外,各均一多糖的一级结构中均不存在1→4糖苷键。结论这6个均一多糖为首次从铁皮石斛原球茎中得到。

英文摘要：

OBJECTIVE To study the physical and chemical properties of polysaccharides in Dendrobium officinale protocorm.METHODS The crude polysaccharides in D.officinal（CDO） and D.officinal protocorm（CDOP） were extracted and purified by consecutive steps of hot-water extraction,alcohol precipitate,deprotein and dialysis.CDOP was then subjected to DEAE cellulose DE-52 and Sephadex G-200 column chromatography to obtain homogeneous polysaccharide.High performance gel permeation chromatography（HPGPC）,gas chromatography（GC）,and periodate oxidation and Smith degradation were used to analyze the physical and chemical properties of polysaccharide.RESULTS CDO was mainly composed of Man and Glu in a molar ratio of 4.29∶1.00.CDOP was mainly composed of Gal,Ara and Glu in a molar ratio of 2.80∶1.00∶0.61.Six homogeneous polysaccharides,including DOPW-1（78×103）,DOPW-2（37×103）,DOPS1-1（287×103）,DOPS1-2（351×103）,DOPS1-3（335×103） and DOPS1-4（171×103）,were isolated from CDOP,and their monosaccharide composition and molar ratio were similar to that of CDOP.In the primary structure of homogeneous polysaccharides,1→3 glycosidic linkage was mainly composed of Gal in addition to Ara,Glu and Rha,and no 1→4 glycosidic linkage could be tested except for in DCPS1-4.CONCLUSION Polysaccarides DOPW-1,DOPW-2,DOPS1-1,DOPS1-2,DOPS1-3 and DOPS1-4 were isolated from D.officinale protocorm for the first time.