细茎石斛多糖的提取分离纯化和性能分析

 目的提取分离细茎石斛水溶性多糖，并研究其结构性质。方法经提取、离心、沉淀、脱蛋白后的粗多糖，进一步用DEAE-纤维素，Sephacryl S-400HR,Sephacryl S-200HR凝胶渗透柱色谱分离纯化，对分离到的主要多糖应用高碘酸氧化、高效凝胶渗透色谱(HPGPC),TLC,GC,GC-MS，IR等方法进行组成结构分析。结果从细茎石斛水溶性多糖提取物中分离到8种均一多糖，DMP1a-1,DMP1a-2,DMP2a-1,DMP3a-1,DMP4a-1,DMP5a-1,DMP6a-1和DMP7a 1,其中DMP1a-1的相对分子质量(Mr)为28 000，葡萄糖、甘露糖组成摩尔比为1：4.798，分子中1→3、1→4(或1→2)、1→6连接的糖苷键数比为8.75∶23.59∶1，红外光谱数据显示为β-D-吡喃甘露聚糖。结论8种均一多糖首次从细茎石斛中分离得到，其中DMP1a-1为β-D-吡喃型葡萄甘露聚糖。

Extraction isolation and characterization of polysaccharide from Dendrobium moniliforme

OBJECTIVE To isolate the water soluble polysaccharides from Dendrobium moniliforme(L.) Sw. and investigate its structural feature. METHODS The polysaccharides prepared from Dendrobium moniliforme were purified with column chromatography on DEAE-cellulose,Sephacryl S-400 HR and Sephacryl S-200 HR.The structural feature of the main polysaccharide was elucidated by periodate oxidation,HPGPC,TLC,GC,GC-MS and IR respeitively. RESULTS Eight polysaccharides,DMP1a-1,DMP1a 2,DMP2a-1,DMP3a-1,DMP4a-1,DMP5a-1,DMP6a-1 and DMP7a-1,were obtained from Dendrobium moniliforme .The results indicated that DMP1a-1 was a glucomannan with a 1∶4.798 glucose mannose ratio and Mr was 28 000.Periodate oxidation analysis indicated DMP1a-1 containing β(1→3,1→4,1→6) glycosidic bond,appeared in the molar ratio of 8.75∶23.59∶1. CONCLUSION Eight polysaccharides are isolated from this medicinal plant for the first time.DMP1a-1 is a β-D-pyranyl glucomannan.