吡啶壳聚糖的制备、表征及体外抗氧化活性研究

Synthesis,Characteristics and in vitro Antioxidant Activity of Pyridine Chitosan

为研究吡啶壳聚糖的抗氧化活性,将吡啶小分子基团经化学接枝合成吡啶壳聚糖,利用傅里叶红外光谱、紫外-可见光谱、核磁共振光谱对其进行结构表征,并测定其取代度、水溶性、毒性及体外抗氧化活性。结果表明,吡啶成功接枝至壳聚糖,得到水溶性较好、取代度为0.66的吡啶壳聚糖,属实际无毒;以水溶性壳聚糖为对照,吡啶壳聚糖对·OH、DPPH自由基的清除能力以及还原能力均有提高;在β-胡萝卜素漂白体系中,吡啶壳聚糖的IC50为0.9 mg·m L-1,当其浓度为1.8 mg·m L-1时,对亚油酸氧化的抑制率为60.7%,优于对照组(27.5%)。本研究为壳聚糖在食品添加剂、自由基清除剂等中的应用提供了理论依据与参考。

The aim of this study is to synthesize pyridine chitosan（ Py-chitosan） by introducing the pyridine group onto the chitosan backbone and test its antioxidant activity. The resulting polymer was characterized by FT-IR,UV-vis and NMR. The degree of substitution（ DS）,solubility,toxicity and in-vitro antioxidant activity of Py-chitosan were further investigated. Results showed that pyridine was introduced onto chitosan with substitution degree of 0. 66 and better water-soluble properties and it was non-toxic. Scavenging power for·OH,DPPH and reducing power of Py-chitosan had been improved compared with water soluble chitosan（ WSC）. In the β- carotene bleaching assay,Py-chitosan showed strong inhibition power towards linoleic acid. Also,IC50 of Py-chitosan was 0. 9 mg·m L^-1and at 1. 8 mg·m L^-1,the inhibition rate was up to 60. 7%,while that of WSC was 27. 5%. The study will provide theoretical basis and reference for application of chitosan in the field of food additives and free-radical scavengers.