RADICAL-CAPTURING REACTION AND ITS REACTION MECHANISM OF QUERCETIN REPRESENTING FLAVONOIDS

继去年对3，5，7-三甲基槲皮素和3，7-二甲基非瑟酮对2，2 '-偶氮二异丁腈（AIBN）的合成自由基捕获反应机理的研究之后，在不同条件下，如pH，为了了解自由基捕获反应的实际条件，对反应溶剂和温度进行了实验，根据不同pH值，使用多种缓冲溶液进行实验，得到如下结果。结果表明，槲皮素和圣草酚在酸性条件下捕获DPPH的能力比在碱性条件下更强。与DPPH相反，两种黄酮类化合物在碱性条件下捕获鸡胚免疫球蛋白的能力更强。通过甲醇、乙醇和丙酮等多种反应溶剂的实验，推测槲皮素和圣草酚对DPPH和Galvinopropyl的捕获能力主要受反应时间的影响，而不受反应溶剂的影响。通过改变反应温度的实验发现，槲皮素对DPPH和Galvinopropyl的捕获能力随反应温度的升高而增加，但增加的趋势并不超出预期。但由于时间所限，本研究未能获得圣草酚的相关数据，由此得出以下结论，虽然本年度的实验还不够充分。为了有效地利用抗氧化成分，了解抗氧化剂和目标自由基的化学和生物化学性质以及考虑反应场的条件是最重要的事情。从而找出每种抗氧化剂使用的内在条件。

Following the study on the radical-capturing reaction mechanism of 3,5,7-trimethyiquercetin and 3,7-dimethylfisetin against a synthetic radical of 2,2'-azobis-isabutylnitrile ( AIBN) in the last year, the reactions of quercetin and/or eriodictyol against 1,1-diphenyl-2-picrylhydrazil (DPPH) and/or galvinoxyl under various conditions such as pH, reaction solvent and temperature were undertaken in order to understand the actual condition on radical-capturing reactions.From the experiments using plural buffer solutions depending upon different pH, the results were obtained as below. It was revealed that DPPH-capturing abilities of quercetin and eriodictyol were more active in the acidic condition compared to the alkaline condition. Contrary to those of DPPH, galvinoxyl-capturing abilities of both flavonoids were more active in alkaline condition. From the experiments using plural reaction soluvents such as methanol, ethanol and acetone, it was presumed that DPPH- and galvinoxyl-capturing abilities of quercetin and eriodictyol were mainly influenced by reaction time, not reaction solvents. The experiments while changing reaction temperature were indicated that DPPH- and galvinoxyl-capturing abilities of quercetin depended the reaction temperature, though the increasing tendency of abilities was little beyond my expection. Still, in this work, the data on eriodictyol were not obtained, because I was restricted by time.From the above, the following view was led, though the experiments in this year were not enough. For the purpose of efficacious utilization of antioxidative constituents, there were the most important things to understand the chemical and biochemical properties of antioxidant and target radicals and to consider the conditions of the reaction field. And then, it can be found out the inherent condition for the use of each antioxidant.