中文摘要：

从金钗石斛茎中获得了1个均一多糖组分DNP-W1B,采用化学与光谱学结合的手段对其一级结构进行了解析.结果表明,DNP-W1B分子量为7.7×105,比旋度[α]2D0=＋81.3°（c 0.3,H2O）,由葡萄糖、阿拉伯糖和半乳糖3种单糖组成,摩尔比为6.2：3.1：0.9.DNP-W1B主链由1,4-和1,6-连接的葡萄糖残基组成,在主链1,6-连接葡萄糖残基的4位形成分支,支链由末端半乳糖残基和阿拉伯糖残基组成.初步的免疫活性实验结果表明,DNP-W1B在体外能促进免疫细胞的增殖.

英文摘要：

Dendrobium nobile Lindl. （Chinese name ＂Jin-Chai-Shi-Hu＂） is a species of Orchidaceae with distribution in Southeast Asia, southwest and south of China. In this work, a water-soluble heteropolysaccha- ride DNP-W1B with a molecular mass of 7.7×10^5 and specific rotation of [ a ] D^20 = ＋81.3°（ c 0. 3, H2O） was isolated from the stems of D. nobile Lindl. Monosaccharide composition analysis showed that DNP-W1B con- tained glucose, arabinose and galactose in a molar ratio of 6. 2 ： 3.1 ： 0. 9. The structural features of DNP- W1B were revealed by the combination of chemical and instrumental analysis, including IR, GC, methylation analysis and NMR. The resuhs showed that DNP-W1B possessed a backbone of a disaccharide unit of [ →4）β-Glcp-（1→6） -β-Glcp-（ 1→] with 33% branches at 0-4 of （1→6） -linkedβ-D-glucopyranosyl residues. The side chains contained arabinosyl and galactosyl chains. Primary immunological tests in vitro indicated that it could stimulate LPS-induced B lymphocyte and Con A-induced T lymphocyte proliferation. Survey showed that DNP-W1B was a novel immunoactive polysaccharide compound from Dendrobium Sw.