黄精多糖的提纯、硫酸化和羧甲基化修饰及其抗氧化活性研究

以黄精为原料,采用超声辅助法提取黄精多糖,经DEAE-52纤维素层析及葡聚糖凝胶层析柱Sephadex G-200分离纯化,得到平均分子量为21.58 kDa的纯黄精多糖(PSP1-A),浓硫酸法制备硫酸酯化多糖(SPSP1-A),氢氧化钠-一氯乙酸体系法制备羧甲基化多糖(CPSP1-A)。通过傅里叶红外光谱法对衍生物进行结构验证,并采用体外实验法对比修饰前后黄精多糖的抗氧化活性。结果表明,黄精多糖提纯修饰后得到取代度为1.44的硫酸化产物和取代度为0.49的羧甲基化产物。在最大浓度10 mg/mL时,CPSP1-A对DPPH·和·OH的清除率分别为74.69%和91.27%。与PSP1-A相比,CPSP1-A对DPPH·和·OH清除力提高,还原力增强,但对ABTS+自由基清除力下降;而SPSP1-A对以上三种自由基的清除作用均增强,10 mg/mL时对DPPH·、·OH和ABTS+·的清除率分别为98.70%、95.72%和97.87%,且还原力明显提高,在10 mg/mL时,SPSP1-A还原力是PSP1-A的三倍多。结果表明,两种修饰均是提高黄精多糖抗氧化能力的有效方法。

Purification,Sulfation Modification and Carboxymethylation Modification of Polysaccharides from Polygonatum sibiricum and Its Antioxidant Activity

Using Polygonatum sibiricum(PS)as raw material,ultrasound-assisted extraction was utilized to extract polysaccharides from Polygonatum sibiricum(PSP),then the polysaccharides were purified by DEAE-52 cellulose chromatography and Sephadex G-200,pure polysaccharides(PSP1-A)were obtained. Sulfated polysaccharides(SPSP1-A)was prepared by concentrated sulfuric acid method,and carboxymethylated polysaccharide(CPSP1-A)was prepared by sodium hydroxide-monochloroacetic acid system. Fourier transform infrared spectroscopy(FTIR)was used to verify the structure of the derivatives,and the antioxidant activity of PSP1-A before and after modification was compared by in vitro experiments. The results showed that the sulfated polysaccharides with a degree of substitution of 1.44 and the carboxymethylated polysaccharides with a degree of substitution of 0.49 were obtained. At the maximum concentration of 10 mg/mL,the scavenging rates of DPPH· and ·OH of CPSP1-A were 74.69% and 91.27%,respectively. Compared with the unmodified PSP1-A,CPSP1-A improved DPPH· and ·OH removal activity,enhanced reductive power,but reduced ABTS+ free radical scavenging activity while SPSP1-A enhanced scavenging effects on the above three free radicals,the scavenging rates of DPPH·,·OH and ABTS+· at 10 mg/mL were 98.70%,95.72% and 97.87%,respectively,and the reducing power was significantly improved,the SPSP1-A reducing power was more than three times that of PSP1-A at the concentration of 10 mg/mL. Both modifications were effective ways to improve the antioxidant capacity of PSP1-A.