中文摘要：

目的：优选黄芪多糖硫酸化修饰的最佳条件,探讨硫酸化修饰提高黄芪多糖活性的可能性。方法：采用氯磺酸-吡啶法对一步醇沉的总黄芪多糖和分步醇沉并纯化的3种分级黄芪多糖进行硫酸化修饰,以氯磺酸-吡啶配比、反应温度和反应时间为因素水平,用L9（3）4正交设计对修饰条件进行优选,用硫酸钡比浊法测定修饰产物的硫酸基取代度（DS）,用MTT法测定修饰产物的抗IBDV活性。结果：黄芪多糖氯磺酸-吡啶法修饰的最佳条件为氯磺酸：吡啶为1：6,反应温度95℃,反应时间1h。结论：硫酸化修饰能提高黄芪多糖的抗病毒活性,且与DS相关。

英文摘要：

Objective： To optimize the sulfated modification conditions of astragalus polysaccharide （APS） and probe into the probability of sulfated modification to enhance APS activity. Methods ： Total APS extracted by one-step ethanol precipitation and three fractional APSs extracted by stepwise ethanol precipitation method and purified were modified by chlorosulfonic acid-pyridine method. The modification conditions were optimized by L9 （ 3^4 ） orthogonal design taking the ratio of chlorosulfonic acid to pyridine, reaction temperature and time. The degree of substitution （DS） was tested by sulfate barium turbidimetric method. The anti-IBDV activity of modification production was tested by MTT method. Results ： The optimized modification conditions were 1 ： 6 of chlorosulfonic acid to pyridine, reaction temperature of 95℃ and reaction time of 1 hour. Conclusion：Sulfated modification can enhance the antiviral activity of APS, which related to DS.