阿魏酸-普鲁兰多糖接枝共聚物的制备及其抗氧化活性研究

Preparation,Characterization,and Antioxidant Properties of Ferulic Acid-grafted-pullulan

普鲁兰多糖为水溶性多糖,在食品加工、农产品及海产品保鲜、包装、医药领域有广泛用途。但是普鲁兰多糖本身的抗氧化性能却不高,从而一定程度上限制了它的应用。本研究选用普鲁兰多糖和阿魏酸为原料,以4-二甲基吡啶(DMAP)和1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC)为催化剂成功制备了三种具有不同接枝度的阿魏酸-普鲁兰多糖接枝共聚物(FAP)。利用核磁共振氢谱、红外光谱、紫外光谱、薄层色谱层析对共聚物进行了结构表征,确定两者是以酯键进行连接。通过共聚物对DPPH、ABTS、羟基自由基的清除能力及还原能力测试,并以普鲁兰多糖为对照,显示共聚物对各种自由的清除作用及还原能力均有显著提高,且随着共聚物中阿魏酸接枝比例的增加而增强,说明两者的复合能显著增强普鲁兰多糖的生化活性。

As a water-soluble polysaccharide,pullulan has been widely used in food processing,preservation and packaging of agricultural and marine products,and in the medical field.However,the lack of strong antioxidant activity of pullulan limits its application to some degree..Therefore,in this study,ferulic acid-grafted-pullulan products with three different degrees of grafting were prepared using 4-dimethylaminopyridine（DMAP） and 1-（3-dimethylaminopropyl）-3-ethylcarbodiimide hydrochloride（EDC） as catalysts and pullulan and ferulic acid as raw materials.Proton nuclear magnetic resonance,Fourier transform infrared spectroscopy（FT-IR）,ultraviolet（UV） spectroscopy,and thin-layer chromatography（TLC） were used to characterize the product structures.The results revealed that ferulic acid and pullulan were linked by ester bonds.Using pullulan as the control,the antioxidant activity of the complex was measured based on its scavenging abilities against 2,2-diphenyl-1-picrylhydrazyl（DPPH）,2,2′-azino-bis（3-ethylbenzothiazoline-6-sulfonic acid）（ABTS）,hydroxyl radical,and total reducing capacity.The results indicated that the scavenging abilities against various free radicals and reducing capacity of the complex were significantly increased,and that this enhancement was more significant as the degree of grafting increased,indicating that the coupling of two compounds can remarkably enhance the biochemical activity of pullulan.