高山红景天多糖的硫酸化修饰及DPPH自由基清除活性研究

Sulfated modification and DPPH free radical scavenging ability of polysaccharide from Rhodiola sachalinensis

目的优选高山红景天多糖(RSP)的最佳硫酸化修饰条件,提高RSP的抗氧化活性。方法利用氯磺酸-吡啶法对RSP进行了硫酸化修饰,并通过单因素实验确定了硫酸化反应的最佳工艺条件;应用红外光谱(IR)和扫描电子显微镜(SEM)对RSP和硫酸化高山红景天多糖(S-RSP)的理化性质进行了分析;通过测定RSP和S-RSP对1,1-二苯基-2-三硝基苯肼(DPPH)自由基的清除能力,考察了S-RSP的取代度(DS)与多糖抗氧化活性之间的关系。结果当氯磺酸与吡啶的体积比为1∶4、反应时间为2 h、反应温度为60℃时,制得的S-RSP的含硫量最大值为18.83%,取代度最大值为2.38。RSP经硫酸化修饰后,增强了其抗氧化活性,S-RSP的DS与DPPH自由基清除能力存在一定的正比例关系。结论氯磺酸与吡啶的体积比影响S-RSP的DS大小;RSP经硫酸化修饰后通过改变多糖的极性而增加了其抗氧化能力。

Objective To optimize the sulfated modification conditions of Rhodiola sachalinensis polysaccharide（RSP） and improve the anti-oxidant activity of RSP. Methods RSP were sulfated by chlorosulfonic acid-pyridine method, and the optimal conditions for the sulfated modification were determined by single factor experiments. The physical and chemical properties of RSP and sulfated RSP（S-RSP） were analyzed by infrared spectroscopy（IR） and scanning electron microscopy（SEM）. The relation between substituting degree（DS） of S-RSP and anti-oxidative activity of polysaccharide was investigated by testing the 1,1-diphenyl-2-picrylhydrazyl（DPPH） free radical scavenging ability of RSP and S-RSP. Results When the volume ratio of chlorosulfonic acid to pyridine was 1∶4, the reaction time was 2 h and the reaction temperature was 60 ℃, the maximum sulfur content of S-RSP was 18.83% and the DS was the highest for 2.38. Moreover, the anti-oxidant activity of RSP was enhanced by the sulfated modification, and there was a certain positive proportional relationship between DS and DPPH free radical scavenging ability of S-RSP. Conclusion The volume ratio of chlorosulfonic acid to pyridine affects the DS of S-RSP, and the sulfated modification can increase the anti-oxidant capacity of RSP by changing its polarity.