Barsacchi R, Kusmic C, Damiani E, Carloni P, Greci L, Donato L
Department of Physiology and Biochemistry, University of Pisa, Italy.
Free Radic Biol Med. 1998 May;24(7-8):1187-92. doi: 10.1016/s0891-5849(97)00431-0.
The effect of melatonin and its precursor N-acetylserotonin was studied in a model of lipid peroxidation induced in human red blood cells by incubation with cumene hydroperoxide (CHP) and H2O2. The oxidative stress was expressed as vitamin E consumption in the presence of melatonin or N-acetylserotonin (concentration ranging from 0.3 to 400 microM): incubation with melatonin not only lacked any protective effect but it induced a dose-dependent extra vitamin E consumption with both CHP and H2O2. On the contrary, N-acetylserotonin showed a strong antioxidant effect at concentrations between 100 and 400 microM. The hydrogen-donating capacity of melatonin and N-acetylserotonin was also evaluated from the decay of the ESR signal of galvinoxyl radical used as hydrogen abstractor. Lack of hydrogen-donating capacity was observed with melatonin, whereas N-acetylserotonin showed a significant hydrogendonating capacity although inferior to vitamin E, thus suggesting that N-acetylserotonin acts by the classical antioxidant mechanism of hydrogen donation. The measurement of the oxidation potential and the specific molecular structure suggest that the vitamin E consumption effect observed with melatonin could be due to the interactions of its radical cation or derivatives on vitamin E.
在通过与氢过氧化异丙苯（CHP）和过氧化氢（H₂O₂）孵育诱导的人红细胞脂质过氧化模型中，研究了褪黑素及其前体N - 乙酰血清素的作用。氧化应激表现为在存在褪黑素或N - 乙酰血清素（浓度范围为0.3至400微摩尔）时维生素E的消耗：与褪黑素孵育不仅没有任何保护作用，而且在CHP和H₂O₂作用下均诱导了剂量依赖性的额外维生素E消耗。相反，N - 乙酰血清素在100至400微摩尔浓度之间表现出强大的抗氧化作用。还通过用作氢受体的加尔文氧基自由基的ESR信号衰减评估了褪黑素和N - 乙酰血清素的供氢能力。褪黑素未观察到供氢能力，而N - 乙酰血清素显示出显著的供氢能力，尽管不如维生素E，因此表明N - 乙酰血清素通过经典的供氢抗氧化机制起作用。氧化电位的测量和特定的分子结构表明，褪黑素观察到的维生素E消耗效应可能是由于其自由基阳离子或衍生物与维生素E的相互作用。
