摘要
采用密度泛函理论(DFT)的方法,分别从静态和动态两大方面分析了黄酮类化合物木犀草素分子不同酚羟基清除自由基活性的大小。分别从该化合物的结构参数、酚羟基(O-H)解离能、半醌式自由基电子的自旋密度分布、前线轨道相关性质分析了其性质与分子活性位的关系,深入解析了木犀草素分子上不同酚羟基清除·OH的反应历程,在UB3LYP/6-311G(d,p)水平下,优化得到了该分子C5、C7位酚羟基与·OH发生抽氢反应的过渡态结构。结果表明,C4'位O-H BDE最小,自旋密度分布最为均匀,·OH可以无需克服能垒直接夺取该位酚羟基H生成自由基和水,该位酚羟基最易失去H,抗氧化活性最大,C5位酚羟基与·OH发生抽氢反应所需要克服的能垒最大,该位酚羟基活性最小。
The free radicals scavenging activity of phenolic hydroxyls on luteolin have been analyzed from static and dynamic based on the data obtained by using the density functional theory （DFT） method. The activity of the phenolic hydroxyls on different sites of luteolin is discussed by the molecular structure parameters, the dissociation energy of the phenolic hydroxyl bonds, the electron spin density distribution and the correlative property of the frontier molecular orbitals（HOMO and LUMO）. The reaction process of the three phenolic hydroxyls on C4＇ C5 and C7 sites scavenging hydroxyl radical（＇OH） have been discussed respectively based on energy in detail. The results show that there is not energy barrier needing to get over for the C4＇-O-H during scavenging hydroxyl radical（＂ OH）. So the transition state structures according to the other two phenolic hydroxyls on C5 and C7 sites to scavenge OH free radical have been optimized by UB3LYP/6-311G（d,p） method. The energy barriers between the transition state and reaction complex are 18.6 and 0.97 KJ mol-1 separately. The C4＇-OH has the highest antioxidation activity and the C5-OH has the lowest activity.
出处
《计算机与应用化学》
CAS
CSCD
北大核心
2013年第12期1483-1488,共6页
Computers and Applied Chemistry
基金
国家自然科学基金资助项目(20972042)
