烟酰化孔石莼多糖的制备及抗氧化活性研究

The preparation of ulvan derivative NU and the study on antioxidant activity in vitro

目的探究烟酰化孔石莼多糖NU的最佳制备工艺,并测定其体外抗氧化活性。方法分别以甲酰胺(FA)、N,N-二甲基甲酰胺(DMF)、二甲基亚砜(DMSO)为溶剂,烟酰氯盐酸盐为酰化剂,以氮元素含量为指标采用单因素法确定最佳溶剂,再采用正交设计法,考察孔石莼多糖U与酰化剂的质量比、U的质量浓度、反应时间、反应温度对反应的影响。经氮元素分析、红外光谱(IR)、核磁共振碳谱(13 C-NMR),推测烟酰化衍生物(NU)的化学结构。并研究NU对超氧阴离子自由基(O_2·^-)、羟自由基(·OH)的清除作用以及还原能力、金属螯合能力。结果烟酰化反应最佳条件:多糖与烟酰化试剂的质量比为1∶2,多糖的质量浓度15g·L-1,反应时间4h、反应温度为125℃。NU的结构已初步确定。对羟自由基(-OH)的清除作用及其还原能力、金属螯合能力,NU与U相比表现出更优的活性;但对超氧阴离子自由基(O_2^-)的清除作用二者无明显差异。结论通过确定的实验方案,烟酰化反应是成功的,烟酰化孔石莼多糖NU的抗氧化活性有显著增强。

Objective To investigate the optimum method for preparation of NU, and determine the antioxidant activity of NU in vitro. Methods The best solvent was determined by the method of single factor experiment using FA, DMF, DMSO as solvent, respectively. The optimum process was studied by the orthogonal design method including mass ratio of U and nicotinoyl, concentration of U, reaction time and temperature. The nitrogen mass percent of NU was determined by nitrogen element analysis, moreover, IR and13C-NMR of U and NU had been studied. The antioxidant activity of the NU in vitro was considered, including scavenging activity on superoxide radical, hydroxyl radical, reduction power and metal chelating activity. Results The optimal reaction conditions were mass ractto ot to aria mcon- noyl（1 ： 2） ,mass concentration of U（15 g·L 1 ） , temperature 125℃ for a reaction duration of 4 h. NU showed stronger antioxidant activity than U on scavenging hydroxyl radical, reducing power and metal chelating activity, however, there was no significant differences between U and NU. Conclusion The preparation of NU was success{ul. The antioxidant activity of NU was much stronger than U on scavenging hydroxyl radical, reducing power and metal chelating activity.