EGCG乙酰化衍生物清除自由基活性的构效分析

王伟伟; 苏威; 江和源; 张建勇; 施莉婷

doi:10.13386/j.issn1002-0306.2017.07.003

EGCG乙酰化衍生物清除自由基活性的构效分析

Analysis on structure-activity of EGCG acetylated derivative to scavenge free radical

摘要

摘要: 以不同取代度乙酰化表没食子儿茶素没食子酸酯(EGCG)为对象,研究了在逐步取代过程中高效液相色谱图出峰时间的变化,以及总抗氧化活性、清除羟自由基、超氧阴离子自由基和DPPH自由基活性。结果表明:乙酰化EGCG出峰时间为14.6~30.6 min,随着乙酸酐添加量的增多,取代羟基数逐渐增加,出峰时间逐渐向后推移。乙酰化EGCG的清除自由基活性表现出不同的规律,其中,总抗氧化活性、清除DPPH自由基活性和清除羟自由基活性随着取代度增加逐渐减弱,其中乙酰化EGCG清除羟自由基活性转变为产生羟自由基活性,清除超氧阴离子自由基活性随着取代度的增加会先升高后降低。由此可见,随着乙酰化程度的增加,EGCG的抗氧化活性有所下降,为乙酰化EGCG产品的研发提供理论依据。

Abstract: Epigallocatechin gallate ( EGCG) with different degrees of acetylating was used in this study, peak reserving time of HPLC and the activity of total antioxidant activity, hydroxyl free radical scavenging, superoxide anion free radical and DPPH free radical scavenging during gradually substituting processing were investigated. The results showed that the peak reserving time of acetylated EGCG was 14.6 ~ 30.6 min, the number of replacing hydroxyl increased and the peak reserving time was delayed with the increasing of acetic anhydride.Free radical scavenging activity of acetylated EGCG exhibited different laws, the total antioxidant activity and DPPH free radical scavenging activity gradually weakened with the increasing of substitution degree, Superoxide anion free radical scavenging activity increased first and then decreased with the increasing of substitution degree, hydroxyl free radical scavenging activity reduced with the increasing of substitution degree, and converted to generating hydroxyl free radicals activity. This suggested that the antioxidant activity of EGCG decreased as the degree of acetylation increased, thus provided the basis for development of acetylated EGCG products.