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

α-生育酚（α-Toc）是生物系统中普遍存在的抗氧化剂，保护生物分子免受各种活性氧诱导的氧化。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介质的作用。此外，NO及其含氧衍生物在较高浓度时产生细胞毒性。由于这些来自NO的活性物质被认为会对身体造成氧化损伤，因此研究它们与α-Toc的相互作用是很重要的。在本研究中，为了揭示NO与α-Toc之间的反应活性和生产相互作用，我们在少量NO和分子氧的条件下进行了NO与α-Toc的反应。由于维生素E存在于生物系统的脂质部分，这些反应在各种有机溶剂中进行。5个主要产物α-邻苯二酚（α-TQ） （max21%）、tocored （max52%）、5-甲酰基- 7,8 -二甲基苯酚（5- fdt） （max29%）、2,3 -二氢-7a-（3-羟基-3,7,11,15-四甲基- 6,10,14 -十六烷基）- 3,5,6,9,11 -六甲基-3（4,8,12 -三甲基-3,7,11 -三烷基）- 1h -pyrano[2,3a]杂蒽-8（7a-H）、11(11a-H)-二酮（toc -二聚体）（max10%）、2-（3-羟基-3,7,11,15-四甲基十六烷基）- 5,6 -二甲基-3-亚硝基-[1,4]苯醌（3-亚硝酸盐）、由α-Toc反应得到。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.