离子化修饰当归多糖衍生物的形貌及体外抗氧化活性研究

The morphology and in vitro antioxidative effect of ionized polysaccharide from Angelica Sinensis

本文旨在研究离子化修饰对当归多糖的形貌及体外抗氧化活性的影响。以当归多糖(ASP)为原料,混合磷酸盐(磷酸二氢钠和磷酸氢二钠)和3-氯-2-羟丙基三甲基氯化铵(CHPTAC)为改性剂,分别对其进行磷酸化、季铵化修饰,得到磷酸化当归多糖(ASP-P)和阳离子化当归多糖(ASP-N),并测定当归多糖的磷酸化和阳离子化的取代度。通过红外光谱、刚果红实验、扫描电镜及热重分析等对离子化当归多糖衍生物进行形貌表征和热稳定性测试。采用羟基自由基、ABTS自由基及DPPH自由基的清除实验,评估离子化修饰前后当归多糖的体外抗氧化能力变化。离子化修饰后的当归多糖具有更好的热稳定性,其中经过磷酸化修饰后的当归多糖热稳定性最好。溶液中离子化修饰的ASP-P/ASP-N保持了ASP的三螺旋骨架构象,但是在固态时呈现较大尺寸的堆积或卷曲的片状形貌。当归多糖的离子修饰产物可显著提高当归多糖对羟基自由基和ABTS自由基的清除能力,具有一定的体外抗氧化能力。上述实验结果为进一步研究当归多糖的衍生化提供了实验依据。

In the present study,the effect of ionization modification on the morphology and in vitro antioxidant activity of Angelica Sinensis polysaccharide(ASP)was researched.ASP was used as raw material to obtain phosphorylated Angelica Sinensis polysaccharide(ASP-P)and cationized Angelica Sinensis polysaccharide(ASP-N).The degree of phosphorylation and cationization of ASP were determined by experiments.Structural characterization and thermal stability testing of ionized ASP derivatives were explored by infrared spectroscopy,thermogravimetric analysis,X-red diffraction,dynamic light scattering,Congo-red test and scanning electron microscopy.The ionization modified ASP have better thermal stability,among which ASP-P has the best thermal stability.ASP-P and ASP-N showed more ordered structure in solid state and the ionized ASP-P and ASP-N in solution all maintain the triple helix architecture of ASP,but exhibited a larger size of stacked or curled sheet morphology in solidity.The scavenging assays of hydroxyl radical,ABTS and DPPH radical were used to evaluate the changes in the antioxidant capacity of ASP before and after ionization modification.The ionic modification products of ASP can significantly improve the scavenging ability in vitro.The above experimental results provide an experimental basis for further research on the derivatization of ASP.