ELUCIDATION OF ANTIOXIDATIVE REACTION MECHANISM ON TREE PHENOLIC

对木材酚类成分的抗氧化活性进行了研究，以期开发木材酚类提取物的有效利用。在此基础上，对黄酮醇的抗氧化能力进行了进一步的表征。首先，旨在揭示发生在黄酮醇C3羟基上的自由基捕获反应途径。在主实验前，以槲皮素-3-0-β-芦丁苷为原料制备了5,7,3',4'-四甲基槲皮素（TMQ）。代表黄酮醇的TMQ与两种反应活性不同的自由基引发剂反应。对分离产物的结构进行了分析。并得到了这些产物的时间过程。在此基础上，提出了一种具有两种漂白方式的反应途径。结果表明，两种自由基引发剂对两种地铁的反应行为是不同的。其次，利用查尔酮、aurone、异黄酮、黄烷-3-醇等天然黄酮类化合物以及黄酮醇成分，通过常规光谱法和停流法比较了黄酮类化合物对1,1-二苯基-2-苦味肼（DPPH）的自由基捕获能力。从这些结果可以看出，黄酮醇具有更大的优势。此外，研究还发现，根据自由基捕获的反应速度，抗氧化成分可分为两类。

We noticed on the antioxidative activity of wood phenolic constituents in order to develop the effective utilization of the extractives. On the present work, further characterization of flavonols on the antioxidative ability was undertaken.At first, the revealing of radical-capturing reaction pathway which gegan at the C3 hydroxyl group of the flavonol was aimed. Before the main experiment, 5,7,3',4'-tetramethylquercetin (TMQ) was prepared from quercetin-3-0-β-rutinoside. TMQ representing flavonols was reacted with two radical initiators having strong and weak reactivities. The structures of isolated reaction products were elucidated, respectively. Also, the time course of these products were obtained. Based on both results, a possible reaction pathway having two blanched ways was presented. It was revealed that the reaction behavior of two subways was different between two radical initiators.Nextly, comparison experiments of the radical-capturing ability against 1,1-diphenyl-2-picrylhydrazil (DPPH) by usual spectroscophic and stopped flow methods were carried out, using natural flavonoids such as chalcone, aurone, isoflavone, flavan-3-ols, and other compounds, together with flavonol constituents. From these results, the more advantage of flavonols was indicated. Furthermore, it was revealed that antioxidative constituents might be divided into two groups due to the reaction speed of radical-capturing.