天然产物研究与开发 ›› 2015, Vol. 27 ›› Issue (4): 645-650.doi: 10.16333/j.1001-6880.2015.04.018

• 研究简报 • 上一篇    下一篇

儿茶素EGCG与其空间异构体GCG的抗氧化活性和反应活性的密度泛函理论研究

王川丕,诸力,周苏娟,张颖彬,刘新*   

  1. 中国农业科学院茶叶研究所,杭州 310008
  • 出版日期:2015-04-28 发布日期:2015-05-08

Density Functional Theory Study on the Antioxidant Activity of EGCG and Its Stereisomer GCG

WANG Chuan-pi,ZHU Li,ZHOU Su-juan,ZHANG Ying-bin, LIU Xin*   

  1. Tea Research Institute,Chinese Academy of Agricultural Sciences,Hangzhou 310008,China
  • Online:2015-04-28 Published:2015-05-08

摘要: 为了分析儿茶素EGCG及其空间异构体GCG自由基清除活性的差异,在6-311++G(d,p)水平下采用密度泛函理论中的B3LYP方法计算EGCG和GCG的酚羟基键解离能(BDE)、电离能(IP)、电子亲和势(EA)、E-HOMO和E-LUMO能级及其能级差E-gap等性质。结果表明:EGCG和GCG的自由基清除反应最有可能发生在B环,这主要是由于B环上的相邻酚羟基之间的弱氢键作用所产生的共轭稳定性;此外研究还发现,GCG比EGCG稳定,但两者具有相同的基于氢原子转移机制(HAT)和电子转移随后发生质子迁移机制(SPLET)的自由基清除活性。

关键词: 密度泛函理论, 儿茶素, 自由基清除活性, 解离能

Abstract: In order to estimate the activity of scavenging free radicals of EGCG and its stereisomer GCG,the hybrid density functional theory B3LYP method at 6-311++G(d,p) level has been used to calculate O-H bond dissociation energies (BDE),ionization potentials (IP),electronic affinities (EA),E0HUMO energies and E-LUMO energies. Results showed that the B ring of EGCG and GCG was the most active site and the free radical reaction was most likely to occur on the B ring on the basis of stability of dehydrogenated EGCG and GCG radicals.This relatively high activity could be attributed to weak hydrogen-bond interactions between two nearby hydroxyls in the B ring of EGCG and GCG.Moreover,GCG was more stable than EGCG and has the same activity of scavenging free radicals as EGCG based on the HAT mechanism and ET-PT mechanism.

Key words: density functional theory, catechin, antioxidant, dissociation energy

中图分类号: 

O641.12