Kurisawa Motoichi, Chung Joo Eun, Uyama Hiroshi, Kobayashi Shiro
Department of Materials Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan.
Biomacromolecules. 2003 Sep-Oct;4(5):1394-9. doi: 10.1021/bm034136b.
Rutin, quercetin-3-rutinoside, is one of the most famous glycosides of flavonoid and widely present in many plants. In this study, we performed an oxidative polymerization of rutin using Myceliophthora laccase as catalyst in a mixture of methanol and buffer to produce a flavonoid polymer and evaluated antioxidant properties of the resultant polymer. Under selected conditions, the polymer with molecular weight of several thousands was obtained in good yields. The resulting polymer was readily soluble in water, DMF, and DMSO, although rutin monomer showed very low water solubility. UV measurement showed that the polymer had broad transition peaks around 255 and 350 nm in water, which were red-shifted in an alkaline solution. Electron spin resonance (ESR) measurement showed the presence of a radical in the polymer. The polymer showed greatly improved superoxide scavenging activity and inhibition effects on human low-density lipoprotein (LDL) oxidation initiated by 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH), compared with the rutin monomer. The polymer also protected endothelial cells from oxidative injury induced by AAPH as a radical generator with a much greater effect than the rutin monomer.
芦丁，即槲皮素 - 3 - 芸香糖苷，是黄酮类化合物中最著名的糖苷之一，广泛存在于多种植物中。在本研究中，我们以嗜热栖热菌漆酶为催化剂，在甲醇和缓冲液的混合物中对芦丁进行氧化聚合反应，以制备一种黄酮类聚合物，并评估所得聚合物的抗氧化性能。在选定条件下，以良好的产率获得了分子量为数千的聚合物。尽管芦丁单体的水溶性很低，但所得聚合物易溶于水、N,N - 二甲基甲酰胺和二甲基亚砜。紫外测量表明，该聚合物在水中于255和350 nm左右有宽的跃迁峰，在碱性溶液中发生红移。电子自旋共振（ESR）测量表明聚合物中存在自由基。与芦丁单体相比，该聚合物对超氧化物的清除活性以及对2,2'-偶氮二异丁脒二盐酸盐（AAPH）引发的人低密度脂蛋白（LDL）氧化的抑制作用有显著提高。该聚合物还能保护内皮细胞免受AAPH作为自由基发生器所诱导的氧化损伤，其效果比芦丁单体大得多。
