目的:分离纯化白花蛇舌草总多糖,研究其对环磷酰胺致免疫低下小鼠的免疫增强活性。方法:采用超滤技术分离纯化白花蛇舌草总多糖,高效凝胶渗透色谱-示差检测器方法测定相对分子质量,柱前衍生化HPLC分析其单糖组成;采用环磷酰胺致免疫低下小鼠碳粒廓清试验研究其免疫活性。结果:从白花蛇舌草中分离得到1个单一多糖组分ODP-1,其相对分子质量20.88 k Da,单糖组成为甘露糖-鼠李糖-半乳糖醛酸-葡萄糖-半乳糖-阿拉伯糖,摩尔比0.005∶0.033∶0.575∶1.000∶0.144∶0.143;免疫活性试验结果表明,ODP-1可升高环磷酰胺致免疫低下小鼠廓清指数、吞噬指数、胸腺指数和脾指数。结论:白花蛇舌草多糖ODP-1为均一多糖,具有免疫增强活性。 OBJECTIVE: To isolate and purify total polysaccharide from Hedyotis diffusa Willd. To study its immunopotentiating activity on immunosuppressed mice induced by cyclophosphamide. METHODS: The total polysaccharide of Hedyotic diffusa was isolated and purified by ultrafiltration and the relative molecular mass was determined by high performance gel permeation chromatography - differential detector. The monosaccharide composition was analyzed by pre-column derivatization HPLC. The immunosuppressive mice were immunosuppressed with cyclophosphamide Carbon clearance test to study its immunocompetence. Results: One single polysaccharide component, ODP-1, was isolated from Hedyotis diffusa. The relative molecular mass was 20.88 kDa. The monosaccharide consisted of mannose-rhamnose-galacturonic acid-glucose-galactose- Sugar, molar ratio of 0.005:0.033:0.575:1.000:0.144:0.143. Immunoassay results showed that ODP-1 increased clearance index, phagocytic index, thymus index and spleen index of immunosuppressed mice induced by cyclophosphamide. Conclusion: Ophiopogon japonicus polysaccharide ODP-1 is a homogeneous polysaccharide with immunopotentiating activity.