白木香叶中黄酮类成分结构与抗氧化功能的相关性研究

目的：研究白木香叶中黄酮类成分清除O2^·-,H2O2,·OH的能力,探讨其抗氧化活性与结构的关系。方法：对白木香叶中黄酮类成分进行分离,采用化学发光法,测定所得成分对邻苯三酚-鲁米诺-碳酸缓冲液体系产生的超氧阴离子（O2^·-）,H2O2-鲁米诺-碳酸缓冲液体系产生的过氧化氢（H2O2）,以及邻菲罗啉-Cu2＋-抗坏血酸-H2O2体系产生的羟自由基（·OH）的清除能力。结果：分得6种黄酮类成分,经鉴定分别为：洋芹素-7,4′-二甲醚（Ⅰ）、5-羟基-7,3′,4′-三甲氧基黄酮（Ⅱ）、木犀草素-7,4′-二甲醚（Ⅲ）、芫花素（Ⅳ）、木犀草素（Ⅴ）、羟基芫花素（Ⅵ）。6种黄酮类化合物具有良好的清除自由基活性。构效关系分析显示,其清除超氧阴离子（O2^·-）、过氧化氢（H2O2）、羟自由基（·OH）的活性强弱与母核上连接的酚羟基数目和位置直接相关。结论：白木香叶中的黄酮类成分具有明显的清除自由基活性,可能为白木香叶的主要抗氧化活性成分。

Antioxidant Activity and Structure-activity Relationship of the Flavones from the Leaves of Aquilaria sinensis

AIM： To study the antioxidant activities of different flavones from the leaves ofAquilaria sinensis （Lout.） Gilg. METHODS： The flavones were isolated from the leaves of A. sinensis. Their antioxidant activities were compared by scavenging the superoxide anion （O2^·-）, hydrogen peroxide （H2O2） and hydroxyl radical （·OH） by chemiluminescence. RESULTS： Six flavonoids were isolated from the leaves of A. sinensis. They were apigenin-7, 4′-dimethylethers（ Ⅰ ）, 7,Y,4′-tri-O-methylluteolin （Ⅱ）, luteolin-7,4′-dimethylethers （Ⅲ）, genkwanin （Ⅳ）, luteolin （Ⅴ）, hydroxygenkwanin（Ⅵ）. There is a close relationnship between their scavenging activities for superoxide anion, hydrogen peroxide and hydroxyl radicals and their structures. CONCLUSION： The flavones from the leaves ofA. sinensis possess strong scavenging activities for superoxide anion （O2^·-）, hydrogen peroxide （H2O2） and hydroxyl radical （·OH）, and are the main antioxidants in the leaves of A. sinensis.