ELUCIDATION OF ANTIOXIDATIVE REACTION MECHANISM ON TREE PHENOLIC

为了开发木材酚类物质的有效利用，我们对木材酚类物质的抗氧化活性进行了研究。本论文对黄酮醇类化合物的抗氧化能力进行了进一步的表征，首先揭示了黄酮醇C3羟基的自由基捕获反应途径。在主要实验之前，从槲皮素-3-0-β-芸香糖苷制备5，7，3 '，4'-四甲基槲皮素（TMQ）。以TMQ为代表的黄酮醇类化合物与两种具有强、弱反应活性的自由基引发剂反应。分离的反应产物的结构分别进行了鉴定。同时，还得到了这些产物的时程。基于这两个结果，提出了一个可能的反应途径，有两个漂白的方式。其次，以天然黄酮类化合物查尔酮、橙酮、黄烷-3-醇等为原料，结合黄酮醇类化合物，采用常规光谱法和停流法，对1，1-二苯基-2-苦基肼（DPPH）的自由基捕获能力进行了对比实验。这些结果表明，黄酮醇类化合物具有更大的优势。此外，还揭示了抗氧化成分可以分为两类，由于自由基捕获的反应速度。

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.