黄酮类化合物抗氧化活性构效关系的密度泛函理论研究

用密度函数方法对黄酮类化合物分子及其自由基进行了理论计算,并从几何结构、前线轨道、单电子分布、离解能等角度分析了影响竹叶黄酮抗氧化活性的结构因素。结果表明:(1)C2-C3之间的双键以及3位羟基的存在使整个黄酮类化合物分子处于同一平面,进而使C环成为A、B环共轭体系的延伸。(2)活性部位主要位于B环和C环的一部分。(3)4羟基活性最高。(4)3羟基对4羟基的协同作用增强了4羟基的活性。

A DFT Study on the Antioxidant Structure-property Relationship of Quercetin

A DFT study was perfoumed on quercetin and its possible radicals,and the geometry,the frontier orbitals,the distribution of unpaired electron and the dissociation energy were employed to elucidate the antioxidant activity-structure relationship of quercetin.It was found that quercrtin is completely planar due to the presence of the double bond between C_2 C_3 and 3-hydroxyl group,and consequently,C ring becomes the stretch of the conjugation systems of A ring and B ring.The dissociation energy and the unpaired electron distribution suggest that 4'hydroxyl is the most active one among the five hydroxyls.And the cooperative effect of 3'hydroxyl improves the activity of 4'hydroxly.