酚羟基取代异黄酮类化合物的抗氧化活性理论筛选

Theoretical screening studies on antioxidant activity of phenolic hydroxyl substituted isoflavones

运用密度泛函理论(Density Function Theory,DFT)中的B3LYP方法,6-31G(d)基组水平上计算了65种酚羟基取代的异黄酮类化合物的前线轨道能级和O-H键离解能(BDE),并讨论了这些化合物抗氧化活性的构效关系。结果表明,B环为异黄酮类化合物抗氧化、清除自由基的主要活性部位;C环的2-OH是必要的增效酚羟基,在增强抗氧化活性具有非常重要的作用;在C2位羟基作用下4'-OH可以显著增强异黄酮类化合物的抗氧化活性,同时3'-OH对4'-OH的协同作用增强了4'位羟基的活性。在所有标题化合物中,C3(2,3,4'-三羟基异黄酮)、C13(2,3,4',5'-四羟基异黄酮)和C22(2,3,3',4',5'-五羟基异黄酮)具有较强的清除自由基活性,可作为潜在的高效抗氧化剂。

We systematically studied frontier orbital energy levels and O-H bond dissociation energies （BDEs） of 65 phenolic hydroxyl substituted isoflavones by the B3LYP method of density function theory （DFT） with 6-31G（d） basis set. The results show that the B ring is the major active fractions of scavenge free radicals. The 2-OH play a very important role in enhancing antioxidant activity. In addition, the 4＇-OH is the most active one under influence of the 2-OH. And, the cooperative effect of 3＇-OH improves the activity of 4＇-OH. Among these isoflavone compounds, C3（3,4＇-OH）, C13（3,4＇,5＇-OH） or C22（3,3＇,4＇,5＇-OH） has the highest activity to scavenge free radicals, suggesting that they may be regarded to be promising candidates for high effective antioxidants.