目的 将传统工艺与膜分离技术联用对马齿苋多糖进行分离纯化,并考察其体外抗氧化活性。方法 采用L₉(4³)正交试验对马齿苋多糖的提取工艺进行优化;对马齿苋粗多糖脱蛋白和脱色素工艺进行优化;采用不同孔径的膜联用对马齿苋多糖进行精制研究;采用Fenton反应、邻苯三酚自氧化反应研究马齿苋多糖清除羟基自由基、超氧离子自由基活性。结果 马齿苋多糖最佳提取条件为100℃,每次3 h,4次。Sevage法、三氯乙酸法和盐酸法脱蛋白多糖的回收率分别为17.05%、9.66%、16.61%。活性炭法、过氧化氢法、丙酮-无水乙醇法和氯仿-正丁醇法除色素多糖的回收率分别为17.04%、17.09%、27.06%、17.58%。膜分离研究表明纯化后的马齿苋多糖主要存在于0.8 μm的渗透液中。马齿苋多糖对羟基自由基、超氧离子自由基的清除率分别为58.89%、38.89%。结论 合适的微滤超滤膜联用可以达到纯化马齿苋多糖的目的。抗氧化活性研究显示马齿苋多糖能清除羟基自由基、超氧离子自由基且呈剂量依赖关系。

Objective To extract and purify the polysaccharide from Portulaca oleracea and evaluate its anti-oxidant activity. Methods Orthogonal experiment design L₉(4³) was employed to optimize the traditional extraction process. The processes of deproteinization and depigmentation were also investigated. Specifications of membrane with different apertures was used to purify the crude polysaccharide. The anti-oxidant activity of the polysaccharide was also evaluated by Fenton reaction and autoxidation of pyrogallol. Results The polysaccharide was extracted at 100℃ for 3 h with four times repeated to give the highest extraction rate. The recycling rates of Sevage method, thicloroacetic acid and hydrochloric acid method to remove protein were 17.05%, 9.66%, and 16.61%, respectively. The recycling rates of active carbon, H₂O₂, acetone-anhydrous ethanol, and chloroformn butanol to remove pigment were 17.04%, 17.09%, 27.06%, and 17.58%, respectively. Much of the polysaccharide were detected in the liquid penetrated from the membrane with apertures of 0.8 μm. The clearance rate of polysaccharide scavenge hydroxyl radical and superoxide radical were 58.89%, and 38.89%. Conclusion The preferred aperture of microfiltration and ultrafiltration membrane can purified P. oleracea. Polysaccharide antioxidant experiment indicates that the polysaccharide could effectively scavenge hydroxyl radical and superoxide radical with dose dependent relationship.

国家自然科学基金资助项目(81373978);国家"十二五"重大新药创制科技重大专项(2011ZX09401-308-037);陕西省科技资源教育厅产业化培育项目(2011JG19)