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

利用结构特异性碳水化合物酶，分析了从苍术根茎中分离得到的阿拉伯半乳聚糖对肠道免疫系统调节活性的表达活性部位。结果表明，部分由β-D-(1-→6)-半乳糖和β-D-(1-→3)-半乳糖主链组成的糖簇表达了肠道免疫系统的调节活性。从活性阿拉伯半乳糖的β-D-(1→3，6)-半乳糖部分中分离出来的低聚糖侧链经纯化后进行结构分析，发现d.p.2-8的低聚糖侧链是仅由β-D-(1→6)-半乳糖组成的线状低聚糖。本研究还表明，由于合成过程中的空间排斥，用人工核合成这些低聚糖的糖簇是不可能的。以β-D-(1→3，6)-半乳聚糖为活性部位的另一种肠道免疫系统调节活性多糖，建立了用多元分析方法比较这些活性多糖β-D-(1-→3，6)-半乳糖链中寡糖侧链的方法。从50种侧链中筛选出5条寡糖链作为活性多糖中常见的低聚糖序列，推测这5条寡糖可能与肠道免疫系统调节活性的表达有关。

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.