怀山药内生真菌Trichoderma sp.L12多糖的提取纯化、理化表征及抗氧化活性研究

Extraction,purification,physicochemical characterization and antioxidant activity of polysaccharides from an endophytic fungus trichoderma sp.L12 from Dioscorea opposite Thunb.

目的研究怀山药多糖内生真菌多糖的提取纯化、理化特征和抗氧化活性。方法从一株来源于怀山药的木霉属真菌Trichoderma sp.L12的菌丝和菌液中分离多糖,分析其胞内多糖(extracellular polysaccharides,JSP)和胞外多糖(intracellular polysaccharides,JYP)的理化性质及抗氧化活性。结果JSP和JYP的糖含量、蛋白含量分别是(836.91±1.57)和(690.58±1.72)mg/g、(19.15±0.61)和(12.33±3.03)mg/g,且二者均未检测到糖醛酸和多酚。JSP和JYP相对分子质量主要以1.305×10^(6)和5.114×10^(4)为主,二者单糖组成均以半乳糖、葡萄糖和甘露糖为主,质量百分比分别为27.6∶46.1∶24.9和33.4∶31.3∶26.4。环境扫描电子显微镜(Environmental scanning electron microscopy,ESEM)结果表明,两种多糖表面均有较多明显的粗糙凹痕,且JSP碎片尺寸相对较大。另外,JSP和JYP在较低浓度下(3.0 mg/mL)清除DPPH自由基作用较强,清除率达到90%和70%,且对羟自由基和超氧阴离子自由基也具有一定的清除能力。结论JSP和JYP均有较好的抗氧化作用,是潜在的天然抗氧化剂,能够为怀山药内生真菌多糖的开发利用提供一定的技术和理论支持。

Objective To investigate the extraction,purification,physicochemical characterization and antioxidant activity of polysaccharides from Dioscorea opposite Thunb.Methods An endophytic fungus Trichoderma sp.L12 isolated from D.opposite Thunb.was selected as experimantal material.The physicochemical properties and antioxidant activities of the extracellular(JSP)and intracellular polysaccharides(JYP)were analyzed.Results The sugar and protein contents of JSP and JYP were(836.91±1.57)and(690.58±1.72)mg/g,and(19.15±0.61)and(12.33±3.03)mg/g,respectively,while no polyphenol and uronic acid were detected.The relative molecular weights of JSP and JYP were mainly 1.305×10^(6)and 5.114×10^(4).Both polysaccharides were mainly composed of galactose,glucose and mannose in the mass percent of 27.6∶46.1∶24.9 and 33.4∶31.3∶26.4,respectively.Environmental scanning electron microscopy(ESEM)examination showed that both polysaccharides had rough surfaces with many distinct depressions,and JSP fragments were relatively larger.JSP and JYP showed strong DPPH radical scavenging activity at low concentrations(3.0 mg/mL),with scavenging rates of 90%and 70%,respectively.They also exhibited some scavenging activity against hydroxyl and superoxide anion radicals.Conclusion Both JSP and JYP exhibit significant antioxidant properties,indicating their potential as natural antioxidants.These findings provide technical and theoretical support for the development and utilization of endophytic fungal polysaccharides from Dioscorea opposita.