远志多糖的分离纯化、结构特征及生物活性

目的:分离纯化远志多糖(polysaccharide of Polygala tenuifolia,PTP),并对其理化性质、抗氧化和降血糖活性进行研究。方法:采用超声波辅助提取、分级醇沉、DEAE-cellulose 52和Sephadex G-100柱色谱分离纯化远志多糖;紫外-可见光谱扫描法、比旋光度法、凝胶渗透色谱法3种方法验证纯度;高效凝胶渗透色谱法测定相对分子质量,高效阴离子交换色谱测定单糖组成;清除1,1-二苯基-2-苦味基肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基和羟自由基评价体外抗氧化活性;测定对α-葡萄糖苷酶抑制能力以研究其降血糖活性。结果:远志多糖经分离纯化后获得组分PTP-1,经3种方法验证PTP-1为均一性良好的多糖,相对分子质量为4.62×10~4,由半乳糖、葡萄糖、甘露糖组成,物质的量比为3.92∶1.00∶2.08。抗氧化活性研究结果表明,PTP-1对清除DPPH自由基和羟自由基呈良好的量效关系,半数清除率浓度IC_(50)分别为0.35 mg/m L和0.51 mg/m L。降血糖活性结果表明,PTP-1对α-葡萄糖苷酶具有较好的抑制能力,IC_(50)值为0.52 mg/m L。结论:远志多糖PTP-1为具有抗氧化和降血糖活性的均一多糖。

Purification and Structural Characterization of Polysaccharide from Polygala tenuifolia and Its Biological Activity

Objective: To isolate and purify a polysaccharide from dried roots of Polygala tenuifolia and to determine its physicochemical properties and biological activity. Methods: The purified polysaccharide was obtained by ultrasonicassisted extraction, alcohol fractional precipitation, deproteinization, decolorization, dialysis, DEAE-cellulose 52 and Sephadex G-100 gel column chromatography. The purity of the final purified product was determined by UV-visible spectroscopy, spin spectrophotometry and gel filtration chromatography (GPC). The relative molecular mass of the polysaccharide was determined by high performance gel permeation chromatography, the monosaccharide composition was analyzed by high performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD), the antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl free radical scavenging assays, and the hypoglycemic activity was evaluated by α-glucosidase-inhibiting activity. Results: A homogeneous polysaccharide (PTP-1) was obtained. The relative molecular mass of PTP-1 was 4.62 × 104. Its monosaccharide composition was composed of galactose, glucose and mannose with a molar ratio of 3.92:1.00:2.08. The polysaccharide showed DPPH and hydroxyl radical scavenging capacity in a dose-dependent manner in a certain concentration range, with IC50 of 0.35 and 0.51 mg/mL, respectively. In addition, it was able to significantly inhibit α-glucosidase activity with IC50 of 0.52 mg/mL. Conclusion: PTP-1 is a pure polysaccharide with antioxidant and hypoglycemic activity.