冬虫夏草多糖的分子结构与免疫活性

Molecular Structure and Immunoactivity of the Polysaccharide From Cordyceps Sinensis (Berk) Sacc

冬虫夏草多糖(在本文中名为CS-81002)是由冬虫夏草菌Cordyceps sinensis(Berk)Sacc在人工发酵条件下产生的胞外多糖。用凝胶过滤法测出CS-81002的分子量Mr=43kD。CS-81002的单糖组成为Man:Gal:Glc=10.3:3.6:1。甲基化分析和部份酸水解结果表明,CS-81002是多分支的杂多糖,由→6)-Manp-(1→形成主链,大约每10个主链Man残基中,有6个在C3位上被取代(即形成→3,6)-Manp-(1→分支),有4个在位C2上被取代(即形成→2,6-Manp-(1→分支),从而形成侧链。主链中还有少许未被取代的Man残基。侧链则由→3-)-Galf-(1→,→4)-Glcf-(1→,→4)-Manp-(1→和→2)-Manp-(1→组成。位于非还原末端的,则三种单糖残基都有。CS-81002在5mg/kg体重×12剂量条件下,对正常的昆明小鼠腹腔巨噬细胞吞噬功能有显著促进作用。在同样剂量条件下,对正常LACA小鼠脾脏溶血斑形成细胞(PFC)对绵羊红细胞的溶血作用无显著影响。不同程度的部份酸水解可使CS-81002的分子量下降,分支减少,并且对巨噬细胞吞噬功能的促进作用亦有下降趋势。在所得到的各个部份酸水解级分(分子量分别为41000,40000,32000,16000和12000)中,分子量为12000的级分对巨噬细胞吞噬功能无促进作用。

CS-81002 was a polysaccharide produced from fermentation medium of a fungus, Cordyceps sinensis (Berk) Sacc.The molecular weight of CS-81002 was 43000 dalton measuring by gel filtration. The monosaccharide composition of CS-81002 was Man:Gal:Glc=10.3:3.6:1.The results of methylation analysis and partially acidic hydrolysis showed that CS-81002 was a heteropolysaccaride with branches.There was a backbone composed of→6-)Man-(1→ . Six out of every ten Man residues of the backbone were substituted at C3 position to form→3,6-)-Man-(1→side chains. Four out of every ten Man residues of backbone were substituted at C2 position to form→-.2,6-)-Man-(1→side chain. Still some other Man residues in the backbone were not substituted. Side chains contained→.3-)-Gal-(1→,→4-)-Glc-(1→,4-)-Man- (1→and→2-)-Man-(1→All three kiads of monosacerides were present at the non-reducing end.CS-81002 showed stimulating effect on phagocytic function of macrophages in normal mice a dosages of 5mg/kg×12. But CS-81002 showed no effect on hemo lysis function of PFC of mice spleen against sheep erythrocytes. Partially acidic hydrolysis decreased the molecular weight of CS-81002 and the number of branches. The effects of hydrolysates of CS-81002 on phagocytic function of mice phagocytes were reduced in accord with the decresing of molecular weight. Among the five hydrolysates with molecular weights of 41000,40000, 32000 16000 and 12000 dalton respectively, Only the hydrolysate with molecular weignt of 12000 dalton showed no effect on the phagocytic function of mice macrophages.