Abstract: Three polysaccharides, namely AP-1, AP-2, AP-3, which were proved to be homo-geneous by glass fiber paper electrophoresis, ultracentrifugation analysis and gel chromatography, were isolated from the stems of Dendrobium aphyllum. The limiting viscosity numbers of three polysaccharides were 426.96, 416.96 and 234.03 respectively. Their molecular weights (Mw) were 86300, 61500 and 43100 respectively.

Key words: Dendrobium aphyllum

摘要： 从兜唇石斛(Dendrobium aphyllum)的茎中提取到3种糖：AP－l，AP－2，AP－3；玻璃纤维纸电泳、超速离心和凝胶层析证明：三者都为单一均匀成分。3种多糖的特性粘数(η)分别为426.96，416.96，234.03；分子量(Mw)分另为86300，61500，43100；旋光度([α]25589)分别为-30.000,-33.000,-17.000。经化学方法和光谱分析证明：AP为β(1→4)连接的、含o-乙酸基的、吡喃型的直链D-葡萄甘露聚糖。动物体内试验表明：AP有免疫增强作用。

关键词: 兜唇石斛, 多糖, O-乙酰葡萄甘露聚糖, 结构, 生物活性