Sukhbold Enkhtsetseg, Sekimoto Shogo, Watanabe Emiko, Yamazaki Akane, Yang Lifeng, Takasugi Mikako, Yamada Koji, Hosomi Ryota, Fukunaga Kenji, Arai Hirofumi
a Department of Biotechnology and Environmental Chemistry , Kitami Institute of Technology , Kitami , Japan.
b Faculty of Engineering , Kyushu Sangyo University , Fukuoka , Japan.
Biosci Biotechnol Biochem. 2017 Aug;81(8):1569-1575. doi: 10.1080/09168451.2017.1314758. Epub 2017 May 2.
Oxidation of low-density lipoprotein (LDL) by reactive oxygen species (ROS) and reactive nitrogen species (RNS) has been suggested to be involved in the onset of atherosclerosis. Oolong tea contains unique polyphenols including oolonghomobisflavan A (OFA). In this study, the effects of OFA on LDL oxidation by ROS and RNS were investigated in vitro. OFA suppressed formation of cholesterol ester hydroperoxides in LDL oxidized by peroxyl radical and peroxynitrite, and formation of thiobarbituric acid reactive substances in LDL oxidized by Cu. In addition, OFA inhibited fragmentation, carbonylation, and nitration of apolipoprotein B-100 (apo B-100) in the oxidized LDL, in which heparin-binding activity of apo B-100 was protected by OFA. Our results suggest that OFA exhibits antioxidant activity against both lipid peroxidation and oxidative modification of apo B-100 in LDL oxidized by ROS and RNS. Polyphenols in oolong tea may prevent atherosclerosis by reducing oxidative stress.
活性氧（ROS）和活性氮（RNS）对低密度脂蛋白（LDL）的氧化作用被认为与动脉粥样硬化的发病有关。乌龙茶含有包括乌龙双黄酮A（OFA）在内的独特多酚。在本研究中，体外研究了OFA对ROS和RNS介导的LDL氧化的影响。OFA抑制了过氧自由基和过氧亚硝酸根氧化LDL过程中胆固醇酯氢过氧化物的形成，以及铜氧化LDL过程中硫代巴比妥酸反应性物质的形成。此外，OFA抑制了氧化LDL中载脂蛋白B-100（apo B-100）的片段化、羰基化和硝化，其中OFA保护了apo B-100的肝素结合活性。我们的结果表明，OFA对ROS和RNS氧化的LDL中的脂质过氧化和apo B-100的氧化修饰均具有抗氧化活性。乌龙茶中的多酚可能通过减轻氧化应激来预防动脉粥样硬化。
