刺五加果水溶性多糖的研究——AS-2的分离纯化与结构探讨

从刺五加果中抽提出水溶性粗多糖。经酸性乙醇分级及反复冻融得到多糖AS-2。AS-2经Sepharose CL-4B柱层析为单一对称峰,经醋酸纤维素膜电泳为一条带,冻融后高速离心无沉淀可证明其为均一级分。G.C分析表明,AS-2由Ara、Xyl、Rha、Gal、Glc组成,其单糖摩尔比为1.6:1.2:1.8:1.0:3.6。AS-2的分子量约为78kD,比旋光度α]_D~(25)=+17°,特性粘度η]=0.068。红外光谱分析含β型糖苷键。部分酸水解、酶解、高碘酸酸化、Smith降解、完全甲基化、G.C,G.C-M.S的分析结果表明,以β(1→3)Glc及β(1→4)Glc构成分子的主链。Glc的C_3上带有分支,约每4个己糖残基带有1个侧链。侧链上,Rha多以1→4苷键相连,部分残基C_2上有分支。Gal存在(1→6)及(1→3)连接方式,多数Glc以(1→6)苷键连结,少数Glc出现在分子非还原末端。位于分子末端的还有Ara与Xyl。

Stndy on Water Soluble Polysaccharides from Acanthopanax Senticosus Fruits Isolation and Purification and Structural Iavestigatiog of AS-2

The soluble rude polysaccharides were obtained from Acanthopanax Senticosus fruits. AS-2 have been isolated by ethanol (pH 2.5) gradation and icedmelted from rude polysaccharides. AS-2 thus obtained homogeneous as shown by Sepharose CL-4B column chromatography and cellulose acetate film electrophoresis. According to the results of G.C, AS-2 is Composed Ara,Xyl, Rha, Gal, Glc, with the molar ratio of 1.6:1.2:1.8:1.0:3.6 aespectively. The molcular weight of AS-2 is 78kD with, α]_D~2.5°= +17°, η]=0.068, and contains β-glycosidic bonds as shown by IR analysis.The structure of AS-2 has determined by partial acid hydrolysis, enzyme hydrolysis, periodate oxidation, Smith degradation, methylation, G.C and G.C-M.S analysis etc, AS-2 is highly branched in Structure. The main chains are constituted of (1→3) Glc and (1→4) Glc residues and the substituent is connected to the C_3 of Glc There are one joned side chains, on average, among 4 residues of Glc. There are (1→4) Rha, (1→4/2) Rha, (1→3) Gal, (1→6) Gal and (1→6) Glc residues on the side chain. The non-reduced ends are composed of Glc, Ara and Xyl.