广东淮山多糖的纯化及化学结构鉴定研究

STUDY ON PURIFICATION AND CHEMICAL STRUCTURE OF POLYSACCHARIDES FROM DIOSCOREA FORDII

广东淮山 (DioscoreafordiiPrainetBurkill)先后经过热水和碱液浸提 ,所得多糖分别经过乙醇沉淀、脱脂、三氯乙酸 (结合两次Sevage法 )脱蛋白、活性炭脱色、SephadexG- 75柱层析 ,可得到经纸层析、旋光度测定、分子质量测定和定性化学反应鉴定为均一性的多糖DFPN -Ⅰ和DFPA -Ⅰ。DFPN -Ⅰ完全酸水解后纸层析及气相色谱分析确定其糖基组成为甘露糖、葡萄糖、半乳糖摩尔比 1.2 6∶1.0 0∶2 .87。DFPA -Ⅰ完全酸水解后纸层析及气相色谱分析 (结合糖醛酸含量测定 )确定其糖基组成为甘露糖、葡萄糖、半乳糖、半乳糖醛酸摩尔比2 .18∶1.0 0∶3.39∶1.82。

Polysaccharides of Dioscorea fordii Prain et Burkill were extracted by hot water and alkali succeededly.The polysaccharide in the filtrate were precipitated by ethanol. The protein in the product were removed by means of trichloroacetic acid followed twice by Sevage method. The polysaccharide was decoloured by active carbon, then purified twice by Sephadex G-75 column chromatography to obtain the homogeneous polysaccharide DFPN-Ⅰand DFPA-Ⅰ, and their homogentity were examined with paper chromatography, polarimetry and molecular weight determination. The units of monosaccharides of DFPN-Ⅰ were identified by paper chromatography and gas chromatography to be mannose, glucose, galactose at ratio 1.26∶1.00∶2.87 after complete hydrolysis by acid. Similarly, the monosaccharides of DFPA-Ⅰ were identified to be mannose, glucose, galactose, galacturonic acid at ratio 2.18∶1.00∶3.39∶1.82(in combination with determination of content of uronic acid).