裸藻非水溶性和水溶性多糖的化学组成及抗氧化活性分析

Analysis of Chemical Composition and Antioxidant Activities of Water-insoluble and Water-soluble Polysaccharides from Euglena gracilis

目的:研究比较裸藻非水溶性和水溶性多糖抗氧化活性,并分析其主要结构特征,为后续研究裸藻多糖的结构与活性关系提供实验基础。方法:以裸藻为原料,提取裸藻中的非水溶性和水溶性多糖,经分离纯化后,采用紫外-可见吸收光谱、红外光谱、凝胶色谱、离子色谱等技术对多糖的基本结构进行分析;进一步以维生素C(VC)为对照,考察它们对DPPH和OH自由基的清除能力及还原能力。结果:裸藻非水溶性多糖(EGP-1)、裸藻水溶性多糖(EGP-2A-1和EGP-2B-1)的相对分子质量分别为1.01×10^(4)、2.91×10^(6)和1.70×10^(6)Da。EGP-1是一种含有β-糖苷键和吡喃葡萄糖环的多糖,EGP-2A-1和EGP-2B-1是含有α-和β-糖苷键的吡喃葡萄糖环形式的多糖。EGP-1主要单糖为葡萄糖、甘露糖、岩藻糖和鼠李糖;EGP-2A-1和EGP-2B-1均由岩藻糖、鼠李糖、阿拉伯糖、盐酸氨基葡萄糖、半乳糖、葡萄糖、木糖、甘露糖和葡萄糖醛酸组成。体外抗氧化活性结果显示,3种组分多糖均具有抗氧化活性,其抗氧化能力为V_(C)>EGP-2A-1>EGP-2B-1>EGP-1。结论:从裸藻中分离得到的多糖均具有抗氧化能力,且水溶性多糖的抗氧化活性强于非水溶性多糖,其中EGP-2A-1组分活性最佳。

Objective:The antioxidant activities and main structural characteristics of water-insoluble and water-soluble polysaccharides of Euglena gracilis were comparatively studied,which provided an experimental basis for the subsequent research of the structure-activity relationship of E.gracilis polysaccharides.Methods:The water-insoluble and watersoluble polysaccharides were extracted,separated and purified from E.gracilis.The basic structure of the polysaccharides was analyzed by UV,IR,HPGPC and IC techniques.The antioxidant activities of these polysaccharides were further investigated by measuring scavenging activities against 1,1-Diphenyl-2-picrylhydrazyl free radical(DPPH·) and hydroxyl radical(·OH),and reducing ability,compared with vitamin C(VC).Results:The molecular weights of E.gracilis waterinsoluble polysaccharides(EGP-1) and E.gracilis water-soluble polysaccharides(EGP-2 A-1 and EGP-2 B-1) were1.01×10^(4),2.91×10^(6) and 1.70×10^(6) Da,respectively.EGP-1 was a glucopyranose cyclic polysaccharide connected by β-glycosidic bonds,and EGP-2 A-1 and EGP-2 B-1 were glucopyranose cyclic polysaccharides containing α-and β-glycosidic bonds.The main monosaccharides found in EGP-1 were glucose,mannose,fucose and rhamnose;EGP-2 A-1 and EGP-2 B-1 were composed of fucose,rhamnose,arabinose,glucosamine,hydrochloride galactose,glucose,xylose,mannose and glucuronic acid.The results of antioxidant activities showed that three-component polysaccharides had antioxidant activity,the order of their antioxidant capacities was V_(C)>EGP-2 A-1>EGP-2 B-1>EGP-1.Conclusions:Both the water-insoluble and water-soluble polysaccharides isolated from E.gracilis had antioxidant capacity,and the antioxidant activity of watersoluble polysaccharides was stronger than that of water-insoluble polysaccharides,and the EGP-2 A-1 was the best.