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

生育酚(α-tocoherol，α-ToC)是生物系统中普遍存在的一种抗氧化剂，它能保护生物分子免受各种活性氧源的氧化。一氧化氮(NO)是一种生物氧化自由基，在许多生理现象中起着中介的作用。此外，由于NO及其含氧衍生物在较高浓度下产生时会产生细胞毒性，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的反应是在有限的NO和分子氧的作用下进行的，以揭示它们之间的反应性和有效的相互作用。由于维生素E存在于生物系统的脂类部分，这些反应在各种有机溶剂中进行。5种主要产物的高产率：三甲基-3-(4，8，12-三甲基-3，7，3-dihydro-7a-(3-hydroxy-3，7，11，15-tetramethyl-6，)-3，5，6，9，10，11a-六甲基-3(4，8，12-三甲基-3，7，11-tridecatrienyl)-1H-pyrano[2，3a]xanthene-8(7a-H)，)，3，5，6，9，10，11a-六甲基-3(4，8，12-三甲基-3，7，α)，5，5，6，9，10，11a-六甲基-3(4，8，12-α)由α-Toc反应得到11(11a-H)-二酮(Toc-二聚体)(最大10%)，2-(3-羟基-3，7，11，15-四甲基十六烷基)-5，6-二甲基-3-亚硝氧甲基-[1，4]苯二酚(3-亚硝酸盐)。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.