不同修饰方法对西瓜皮多糖结构和抗氧化性的影响

Effect of Different Modification Methods on the Structure and Antioxidant Activity of Exocarpium Citrulli Polysaccharides

为探索不同修饰方法对西瓜皮多糖结构和抗氧化活性的影响,对西瓜皮提取分离得到的多糖ECP-3进行了硫酸化、锌螯合及与茶多酚复合3种不同的修饰,制备出3种修饰多糖(ECP-S、ECP-Zn和ECP-g-GA);并通过紫外全波长、傅里叶红外光谱、热重、扫描电子显微镜探究不同修饰方法的西瓜皮多糖结构;通过考察西瓜皮多糖对1,1-二苯基-2-三硝基苯肼(1,1-Diphenyl-2-picrylhydrazyl,DPPH)自由基、2,2-联氨-双-3-乙基苯并噻唑啉-6-磺酸(2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS)阳离子自由基、羟基自由基的清除能力分析其体外抗氧化活性。结果表明:ECP-3、ECP-S、ECP-Zn和ECP-g-GA的总糖含量分别为95.51%±1.16%、46.23%±0.01%、86.64%±0.01%和78.46%±0.01%。ECP-S的硫含量为14.89%±0.70%,ECP-Zn的锌含量为(18.01±0.18)mg/g,ECP-g-GA的多酚含量为10.45%±0.14%;3种修饰多糖的抗氧化活性均高于原始多糖(ECP-3),其中ECP-g-GA的抗氧化活性最高,在质量浓度为4.0 mg/mL时对DPPH自由基、ABTS阳离子自由基、羟基自由基的清除率分别高达98.44%、90.1%、77.9%。研究表明,不同的修饰方法可以显著影响多糖的特性和生理活性。该研究结果可为多糖修饰以及修饰多糖在食品和制药领域的应用提供借鉴。

To explore the effects of different modification methods on the structure and antioxidant activity of Exocarpium Citrulli polysaccharides,three different modifications were carried out on the polysaccharide ECP-3 isolated from Exocarpium Citrulli,encompassing sulfation,zinc chelation,and complexation with tea polyphenols,and three modified polysaccharides:ECP-S,ECP-Zn,and ECP-g-GA were prepared.The structure of different modified Exocarpium Citrulli polysaccharides was employed by UV spectroscopy,Fourier infrared spectroscopy,thermogravimetric analysis,scanning electron microscopy,and the in vitro antioxidant activity of the polysaccharides was analyzed by examining the scavenging ability on DPPH radicals,ABTS cation radicals and OH radicals.The results showed that total sugar content of ECP-3,ECP-S,ECP-Zn,and ECP-g-GA was 95.51%±1.16%,46.23%±0.01%,86.64%±0.01%,and 78.46%±0.01%,respectively.In addition,the sulfur content of ECP-S was 14.89%±0.70%,the zinc content of ECP-Zn was(18.01±0.18)mg/g,and the polyphenol content of ECP-g-GA was 10.45%±0.14%.All three modified polysaccharides exhibited higher antioxidant activity than the original polysaccharides(ECP-3).Among them,ECP-g-GA had the highest antioxidant activity,with clearance rates of 98.44%,90.1%,and 77.9%for DPPH radicals,ABTS cation radicals,OH radicals at a mass concentration of 4.0 mg/mL,respectively.The results indicated that different modification methods can significantly affect the characteristics and biological activity of polysaccharides,and providing a reference for future research on polysaccharide modification and the application of modified polysaccharides in the food and pharmaceutical fields.