A Study on the Action of Antioxidants and Development of Synergists

现在有越来越多的证据表明自由基介导的脂质、蛋白质、酶和核酸的氧化参与各种病理事件、癌症和衰老。本研究旨在阐明各种断链抗氧化剂的作用速率和机理以及协同抑制氧化的作用。（维生素C）、尿酸、半胱氨酸和谷胱甘肽通过在水自由基攻击膜之前清除水自由基而充当抗氧化剂。然而，它们不能清除膜和低密度脂蛋白的脂质层内的亲脂性自由基。在均相溶液中，通过测定氧摄取、产物形成、化学发光和电子自旋共振自由基，研究了维生素E对脂质过氧自由基的清除速率和机制。氧化物 关于我们 研究了磷脂脂质体膜的抗氧化作用及其抑制作用，旨在阐明膜中抗氧化剂的作用。结果发现，生育酚抑制磷脂酰胆碱脂质体膜的氧化，通过清除水的自由基攻击从膜外和膜内的亲脂自由基。有人建议，横向生育酚更迅速，但它得到较少的流出物生育酚，以消除自由基，因为他们深入到膜的内部。植基侧链对生育酚在膜中的保留有深远的影响，但它使生育酚难以在膜之间移动。另一方面，2，2，5，7，8-五甲基-6-色原烷醇可以自由地穿透脂质体膜并在脂质体膜之间转移。Tocophemls还抑制自由基诱导的氧化溶血。结果发现，红细胞膜内的生育酚是最有效的抑制溶血，清除链携带自由基和打破链增长。研究了抗氧化剂与金属离子的相互作用。本文还研究了生育酚与还原剂如抗坏血酸、半胱氨酸和谷胱甘肽协同抑制氧化的速率和机理。少

There is now an increasing number of evidence which suggests the involvement of free radical mediated oxidations of lipids, proteins, enzymes, and nucleic acids in a variety of pathological events, cancer and aging. This study was carried out aiming at elucidating the rate and mechanism of the action of various chain-breaking antioxidants and also the synergistic inhibition of oxidation.The water-soluble antioxidants such as ascorbic acid (vitamin C), uric acid, cysteine, and glutathione acted as antioxidant by scavenging aqueous radicals before they attack the membranes.However, they can not scavenge lipophilic radicals within the lipid layer of membranes and low density lipoprotein. Tocopherols (vitamin E) acted as lipophilic antioxidant within the membranes.The rate and mechanism of scavenging of lipid peroxyl radicals were fint studied in homogeneous solution by measuring oxygen uptake, products formation, chemiluminescence, and free radicals with election spin resonance. The oxida … More tion of phospholipid liposomal membranes and its inhibition were studied aiming specifically at elucidating the action of antioxidants in the membranes. It was found that tocopherols suppress the oxidation of phosphatidylcholine liposomal membranes by scavenging both aqueous radicals attacking from outside of the membranes and lipophific radicals within the membranes. It was suggested that laterally tocopherols more fairly rapidly but that it gets less effluent for tocopherols to scavenge radicals as they go deeper into the interior of the membrane. The phytyl side chain had a profound effect in the retainment of tocopherols in the membranes but it makes tocopherols difficult to move between the membranes. On the other hand, 2,2,5,7,8-pentamethyl-6-chromanol could penetrate and transfer between the liposomal membranes freely. Tocophemls also suppressed the oxidative hemolysis induced by free radicals. It was found that tocopherol within the erythrocyte membranes was the most effective in suppressing hemolysis by scavenging chain-carrying radicals and breaking the chain propagation. The interaction between antioxidants and metal ion was also studied. The rate and mechanism of synergistic inhibition of oxidation by tocopherol and reducing agent such as ascorbic acid, cysteine and glutathione have been also studied. Less