玉竹多糖分离纯化、理化性质及抗氧化功能

Isolation,purification,physicochemical properties and antioxidant activity of polysaccharides from polygonatum odoratum

采用热水浸提法从玉竹提取获得多糖POA,进一步利用乙醇分级沉淀方法进行分离纯化,获得均一性较好的POA-70P和POA-70S组分,进一步分析了多糖单糖组成、相对分子质量、红外光谱等基本理化性质,并通过DPPH自由基清除能力和羟基自由基清除能力评价其体外抗氧化功能。结果表明,玉竹多糖POA-70P和POA-70S主要由中性糖组成,相对分子质量分别为4.51×10~4 Da和3.89×10~3 Da,单糖组成分析显示,POA-70S中存在大量的果糖,及少量岩藻糖、葡萄糖、甘露糖,POA-70P中主要存在甘露糖,葡萄糖和半乳糖,以及少量的阿拉伯糖和半乳糖醛酸;此外玉竹多糖POA、POA-70P和POA-70S对羟基自由基有较好的清除作用,浓度为4 mg·mL^(-1)清除能力能达到48%,并呈现剂量依赖性;但对于DPPH自由基清除能力较差,浓度从0.5 mg·mL^(-1)增大到4 mg·mL^(-1)的过程中,清除能力始终处于20%左右。

The polysaccharide was extracted from Polygonatum odoratum by hot water(POA),and then separated and purified by ethanol fractional precipitation to get two sub-purified components POA-70 P and POA-70 S.The physical and chemical properties were analyzed,which included monosaccharide composition,molecular weight,FT-IR spectra.The antioxidant abilities of polysaccharides from Polygonatum odoratum were evaluated by DPPH free radical scavenging and hydroxyl free radical scavenging activities.The results showed that POA-70 S and POA-70 P were mainly composed of neutral sugars with the molecular weights were 4.51×10^4 Da and 3.89×10^3 Da,respectively.A large amount of fructose and a small amount of fructose,glucose and mannose existed in POA-70,while mannose and a small amount of arabinose,galactose,glucose,and galacturonic acid were found in POA-70 P.Antioxidant experiments of POA,POA-70 S and POA-70 P showed that it could scavenge hydroxyl radicals in a dose-dependent manner,the scavenging capacity of 4 mg·mL^-1 reached 48%;while the DPPH radical scavenging activity was poor,When the concentration increased from 0.5 mg·mL^-1 to 4 mg·mL^-1,the scavenging capacity fluctuated around 20%.