目的 分离纯化滇黄精Polygonatum kingianum中的均一多糖，并阐释其理化性质和抗氧化活性。方法 通过水提醇沉、分级醇沉得滇黄精总多糖（PKS）的50%和70%醇沉部位，再经DEAE-琼脂糖凝胶FF离子交换柱和Sephadex G-100柱色谱法分离纯化得到均一多糖，并利用柱前衍生化HPLC、高效凝胶渗透色谱法和红外光谱法分别对其单糖组成、相对分子质量和结构进行研究；同时采用总还原力实验、1-二苯基-2-三硝基苯肼（DPPH）和羟基自由基（·OH）清除法对其抗氧化活性进行评价。结果 从50%和70%醇沉部位分离纯化得到3个均一多糖（PKS-1、PKS-2和PKS-3），其单糖组成均含有D-甘露糖、D-半乳糖醛酸、D-葡萄糖醛酸、D-半乳糖、D-阿拉伯糖和L-岩藻糖，其中PKS-1及PKS-3还分别含有D-核糖和L-鼠李糖；相对分子质量分别为85 017.83、266 084.76和474 799.22；PKS、PKS-1和PKS-2的总还原能力、·OH及DPPH自由基的清除能力为PKS>PKS-2>PKS-1。结论 从滇黄精50%和70%醇沉部位分离到3个均一多糖，均为含有β构型的吡喃环酸性多糖，其单糖组成相似，PKS、PKS-1和PKS-2均有一定的抗氧化活性，为滇黄精抗氧化活性成分的研究及抗衰老药物和功能性食品的开发利用奠定了科学基础。

Objective To investigate the physicochemical properties and antioxidant activities of homogeneous polysaccharides isolated from Polygonatum kingianum. Methods The polysaccharides (PKS) were extracted with hot water, followed by precipitating with 50% and 70% alcohol precipitation site. Three homogeneous polysaccharides were purified by DEAE-Sepharose fast flow ion column and Sephadex G-100 gel column chromatography from PKS. The monosaccharide composition and molecular ratio, molecular weight and structural analysis of homogeneous polysaccharides were detected by pre-column derivatization HPLC, HPGPC-ELSD chromatograms and infrared spectroscopic, respectively. The antioxidant activities of polysaccharides were evaluated by the reducing power, DPPH free radical and hydroxyl rdical scavenging ability.Results Three homogeneous polysaccharides (PKS-1, PKS-2, PKS-3) were obtained from 50% and 70% alcohol precipitation site. Their monosaccharide composition was mainly D-mannose, D-GalA, D-GlcA, D-galactose, D-arabinose and L-fucose, and with a small amount of D-ribose, L-rhamnose in PKS-1 and PKS-3, respectively. The molecular weight of PKS-1, PKS-2, PKS-3 was 85 017.83, 266 084.76, and 474 799.22, respectively. The order of antioxidant activities was as follows:PKS>PKS-2>PKS-1.Conclusion Three polysaccharides were obtained from PKS with pyranoid rings, β type of anomeric carbon configuration and similar monosaccharide composition. Antioxidant activity test showed that PKS, PKS-1 and PKS-2 exhibited some antioxidant activity in a dose-dependent manner. This research may provide the theoretical basis for scientists researching antioxidant components, searching for anti-aging drugs and developing functional food from P. kingianum.

R286.2

国家自然科学基金资助项目（31460086）；云南省重大科技专项（202002AA100007）；大理大学创新团队项目（ZKLX2019318）；云南省院士专家工作站；云南省青年拔尖人才支持计划（段宝忠）