Clarification of oligosaccharides for modulation of common mucosal immune system by using formation of artificial oligosaccharide clusters

通过使用结构特异性的糖酶，分析活性位点的表达的肠道免疫系统调节活性的阿拉伯半乳聚糖分离自兰芝的根茎DC。由β-D-（1→6）-半乳糖和β-D-（1→3）-半乳聚糖组成的半乳糖侧链构成的糖簇具有肠道免疫调节活性。经酶解后，从活性阿拉伯半乳聚糖的β-D-（1→ 3，6）-半乳聚糖部分释放出的寡糖侧链经纯化后进行结构分析，发现d.p.2-8的寡糖侧链是仅由β-D-（1→6）-半乳糖组成的直链寡糖。本研究还表明，由于合成过程中的空间排斥，使用人工核心合成这些寡糖的糖簇是不可能的。从一些植物中分离得到了以β-D-（1→ 3，6）-半乳聚糖为活性部位的其他肠道免疫调节多糖，并建立了用多元分析比较这些活性多糖β-D-（1→ 3，6）-半乳聚糖中寡糖侧链的新方法。从该分析中，从50种侧链中选择5种寡糖链作为活性多糖中常见的寡糖序列，并假设这5种选择的寡糖可能有助于表达肠道免疫系统调节活性。

By using structure-specific carbohydrases, the active site was analyzed for expression of intestinal immune system modulating activity of the arabinogalactan isolated from rhizomes of Atractylodes lancea DC. It was strongly suggested that the glycocluster, which was constructed from galactosyl side chains consisting partly of β-D-(1→6)-galactose and the main chain of β-D-(1→3)-galactan, express the intestinal immune system modulating activity. After the oligosaccharide side chains, which were liberated from the β-D-(1→3,6)-galactan moiety of the active arabinogalactan by enzymic digestion, were purifed to anlyze the structure, and it was found that the oligosaccharide side chains having d.p.2-8 were the linear oligosaccharides consisting only of β-D-(1→6)-galactose. The present study also showed that the synthesis of glycocluster of these oligosaccharides by using the artificial core was impossible to perform because of the steric exclusion during the synthetic procedure. The other intestinal immune system modulating polysaccharides consisting of β-D-(1→3,6)-galactan as the active sites were isolated from some plant materials, and the new method was developed for comparing oligosaccharide side chains in the β-D-(1→3,6)-galactan chains of these active polysaccharides, by using multivariate analysis. From this analysis, 5 oligosaccharide chains among 50 kinds of the side chains were selected as the commonly-detected oligiosaccharide sequences in the active polysaccharides, and it was assumed that these 5 selected oligosaccharide might be contribute to expression of the intestinal immune system modulating activity.