不同取代度蕨麻硒多糖的制备、表征及体外抗氧化活性

Preparation,Characterization and in Vitro Antioxidant Activity of Selenium Potentilla anserina L. Polysaccharide with Different Substitution Degrees

硒多糖具有抗金属中毒、抗氧化、抗病毒等多种作用,其结构与活性密切相关。本文以从我国传统藏药蕨麻中提取的蕨麻多糖为前体物,通过单因素和响应面设计来优化工艺并调控条件制备出不同取代度的蕨麻硒多糖,使用尺寸排除色谱-激光光散射联用仪、紫外光谱仪、红外光谱仪、热重分析仪、扫描电镜对产物结构进行表征,最后评估了不同取代度蕨麻硒多糖的体外抗氧化活性。结果表明:蕨麻硒多糖的最佳硒化时间为134.84 min,温度78.39℃,催化剂量49.37 mg,投料比PAP∶H2SeO3=1∶0.81,此条件下产物的硒含量可达到8518.81μg/g;制备出的五种取代度的蕨麻硒多糖结构中均含有Se=O键和Se-O键,即实现了蕨麻多糖的硒化;取代度越高的蕨麻硒多糖的分子量越小、热稳定性越低、空间结构越松散,蕨麻硒多糖对O-2·、·OH和DPPH·的清除能力明显且随硒取代度的增加而增强。

Selenium polysaccharide has multiple functions of anti-metal poisoning,anti-oxidation,anti-virus etc. Its activity is closely related to its structure. In this paper,the Potentilla anserina L. polysaccharide extracted from traditional Tibetan medicine potentilla was used as a precursor. Optimizing the preparation process and regulated the conditions by single factor and response surface design to prepare different substitution degrees of Potentilla anserina L. polysaccharides. The size exclusion chromatography-laser light scattering spectroscopy,UV spectrometer,infrared spectrometer,thermogravimetric analyzer,and scanning electron microscopy were used to characterize the structure of the product and evaluated the in vitro antioxidant activity of different substitution degrees of selenium Potentilla anserina L. polysaccharide in the end. The results showed that the optimum reaction time of selenium Potentilla anserina L. polysaccharide was 134.84 min,temperature 78.39 ℃,catalyst 49.37 mg and wight ratio PAP∶H2SeO3=1∶0.81. Under these conditions,the selenium contents of the product was 8518.81 μg/g. There existed Se=O and Se-O bonds in selenium Potentilla anserina L. polysaccharide with five degrees of substitution,meaning the selenization of the Potentilla anserina L.polysaccharide was successful. The higher degree of substitution of selenium Potentilla anserina L. polysaccharide,the smaller the molecular weight,the lower the thermal stability,and the looser the spatial structure. The selenium Potentilla anserina L. polysaccharide had significant scavenging ability to O-2·,·OH and DPPH·,and had positive correlation to the substitution degree of selenium.