黄酮类化合物抗氧化活性的构效关系

分别应用DPPH分光光度法和连苯三酚自氧化法比较了4种黄酮类化合物及5种具有羟基的化合物的抗氧化活性。结果表明,这些化合物由于分子结构上的相似性而都具有一定的抗氧化活性,其清除DPPH作用大小顺序依次为:槲皮素>连苯三酚>芦丁>儿茶素>邻苯二酚>抗坏血酸>桑色素>间苯二酚>苯酚,并且这种作用随其浓度的增加而增大;而对连苯三酚自氧化反应的抑制作用强弱顺序依次为:抗坏血酸>邻苯二酚>间苯二酚>苯酚>芦丁>儿茶素>槲皮素>桑色素。结合试验数据从而推断除抗坏血酸以外的8种化合物的构效关系为:①邻位羟基清除自由基的活性强于间位羟基;②同样在B环上具有邻位羟基的条件下,C环的2,3位为双键结构时,清除自由基的作用增强;③C环3位上羟基被糖基化时可能减弱其他酚羟基活性。

Structure-activity Relationship of Flavonoids in Antioxidant Activity

A study of the antioxidant activity of four flavonoids and five hydroxyl compounds was carried out by DPPH method and pyrogallol method. The result showed the tested samples all had the antioxidant activity. The orders of the DPPH scavenging ability was quercetin>pyrogallol>rutin>catechin>catechol>ascorbic acid>morin>resorcinol>phenol.The effect of restraining pyrogallol autoxidation in turns was ascorbic acid>catechol>resorcinol>phenol>rutin>catechin >quercetin>morin. Therefore it was discovered that the activities of the adjacent hydroxyl groups in scavenging free radical were increased. And C ring with C2-C3 double bond could enhance its effect in scavenging free radical on condition that B ring had the adjacent hydroxyl. When the hydroxyl group at 3 position on the C ring was glycosylated, it could weaken other hydroxyl groups.