The mechanistic study of the interaction between α-tocopherol and biological oxidative radicals

α-生育酚（α-Tocopherol，α-Toc）是生物体内普遍存在的抗氧化剂，能保护生物分子免受各种活性氧的氧化。一氧化氮（NO）是一种生物氧化自由基，在许多生理现象中扮演着介导者的角色。此外，NO及其氧化衍生物在较高浓度下产生细胞毒性，这些活性物质对机体有氧化损伤作用，因此研究它们与α-Toc的相互作用具有重要意义。在这项研究中，NO与α-Toc的反应是使用有限量的NO和分子氧进行的，以揭示它们之间的反应性和生产性相互作用。由于维生素E存在于生物系统的脂质部分，因此这些反应在各种有机溶剂中进行。5-甲酰基-7，8-二甲基母育酚（5-FDT）（最高29%）、2，3-二氢-7a-甲基-β-生育酚（5-FDT）（最高52%）、α-对苯醌（α-TQ）（最高21%）、α-生育酚（α-TQ）（最高52%）、2，3-二氢-7a-（3-羟基-3，7，11，15-四甲基-6，10，14-十六碳三烯基）-3，5，6，9，10，11 a-六甲基-3（4，8，12-三甲基-3，7，11-十三碳三烯基）-1H-吡喃并[2，3a]氧杂蒽-8（7a-H），11（11 a-H）-二酮α-Toc反应生成2-（3-羟基-3，7，11，15-四甲基十六烷基）-5，6-二甲基-3-亚硝氧基甲基-[1，4]苯醌（3-亚硝酸根）（最大10%）。采用高效液相色谱梯度洗脱法进行分析。

α-Tocopherol (α-Toc) is a ubiquitous antioxidant in biological systems and protects biological molecules from the oxidation induced by various kinds of active oxygens. Nitric oxide (NO), which is a biological oxidative radical, has been known to fill the roles of mediators in many physiological phenomena. In addition, NO and its oxygenated derivatives bring about cytotoxicity when they are generated in relatively high concentration.Since these active species derived from NO are supposed to give oxidative damages to the body, it is important to investigate their interaction with α-Toc. In this study, the reactions of NO with α-Toc was carried out using limited amounts of NO and molecular oxygen in order to reveal a reactivity and a productive interaction between them. Since vitamin E exists in lipid part of the biological system, these reactions were carried out in various organic solvents. The high yields of five major products, αptocquinone (α-TQ) (max21%), tocored (max52%), 5-formyl-7, 8-dimethyltocol (5-FDT) (max29%), 2, 3-dihydro-7a-(3-hydroxy-3,7,11,15-tetramethyl-6, 10, 14-hexadecatrienyl)-3, 5, 6, 9, 10, 11a-hexamethyl-3(4, 8, 12-trimethyl-3, 7, 11-tridecatrienyl)-1H-pyrano[2,3a]xanthene-8(7a-H), 11(11a-H)-dione(Toc-dimer) (max10%), 2-(3-hydroxy-3, 7, 11, 15-tetramethylhexadecyl)-5, 6-dimethyl-3-nitrosoxymethyl-[1, 4] benzoquinone (3-Nitrite), were obtained from the reaction of α-Toc. These were analyzed by the gradient elution method with the high performance liquid chromatograhy.