Felim Anne, Urios Amparo, Neudörffer Anne, Herrera Guadalupe, Blanco Manuel, Largeron Martine
UMR 8638 CNRS, Université Paris Descartes, Synthèse et Structure de Molécules d'Intérêt Pharmacologique, Faculté des Sciences Pharmaceutiques et Biologiques, 4 Avenue de l'Observatoire, 75270 Paris cedex 06, France.
Chem Res Toxicol. 2007 Apr;20(4):685-93. doi: 10.1021/tx6003584. Epub 2007 Mar 14.
Several catechol-thioether metabolites of MDMA (ecstasy), three monoadducts, 5-(glutathion-S-yl)-N-methyl-alpha-methyldopamine (1), 5-(N-acetylcystein-S-yl)-N-methyl-alpha-methyldopamine (2), and 5-(cystein-S-yl)-N-methyl-alpha-methyldopamine (3), and two bi-adducts, 2,5-bis(glutathion-S-yl)-N-methyl-alpha-methyldopamine (4) and 2,5-bis(N-acetylcystein-S-yl)-N-methyl-alpha-methyldopamine (5), have been synthesized through an environmentally friendly one-pot electrochemical procedure. Their cytotoxicity profiles were further characterized using simple Escherichia coli plate assays and compared with those of N-methyl-alpha-methyldopamine (HHMA), dopamine (DA), and its corresponding catechol-thioether conjugates (monoadducts 6-8 and bi-adducts 9 and 10). Toxicity mediated by reactive oxygen species (ROS-TOX) was detected in the OxyR- assay, using cells sensitive to oxidative stress due to a deficiency in the OxyR protein. Toxicity arising from the high susceptibility of quinone toward endogenous nucleophiles (Q-TOX) was detected using OxyR+ cells, in the presence of tyrosinase, to promote catechol oxidation to the corresponding o-quinone. At the exclusion of 5-(cystein-S-yl) mono-conjugate 3, which was devoid of any toxicity, all compounds produced ROS-TOX, which was enhanced in the presence of tyrosinase, suggesting that the generated o-quinone (or o-quinone-thioether) species can enter redox cycles through its semiquinone radical, leading to the formation of ROS. The sequence order of toxicity was HHMA approximately = 1 approximately = 2 approximately =5 >> 7 > DA approximately = 4 > 10 > 6 > 8. In contrast, no Q-TOX arising from the binding of quinones with cellular nucleophiles was evidenced, even in the presence of tyrosinase. Finally, taking into account that several different pathways could contribute to the overall MDMA toxicity and that HHMA and catechol-thioether conjugates 1-5 have not been undoubtedly established as in vivo toxic metabolites of MDMA, it can be suggested that these compounds could participate in the toxic effects of this drug through the efficiency of redox active quinonoid centers generating ROS.
已通过一种环境友好的一锅电化学方法合成了摇头丸（3,4－亚甲基二氧甲基苯丙胺）的几种儿茶酚硫醚代谢物、三种单加合物，即5-(谷胱甘肽-S-基)-N-甲基-α-甲基多巴胺(1)、5-(N-乙酰半胱氨酸-S-基)-N-甲基-α-甲基多巴胺(2)和5-(半胱氨酸-S-基)-N-甲基-α-甲基多巴胺(3)，以及两种双加合物，即2,5-双(谷胱甘肽-S-基)-N-甲基-α-甲基多巴胺(4)和2,5-双(N-乙酰半胱氨酸-S-基)-N-甲基-α-甲基多巴胺(5)。使用简单的大肠杆菌平板试验进一步表征了它们的细胞毒性特征，并与N-甲基-α-甲基多巴胺(HHMA)、多巴胺(DA)及其相应的儿茶酚硫醚共轭物（单加合物6-8和双加合物9和10）进行了比较。在OxyR-试验中检测了由活性氧介导的毒性(ROS-TOX)，该试验使用的细胞由于缺乏OxyR蛋白而对氧化应激敏感。在酪氨酸酶存在的情况下，使用OxyR+细胞检测了由于醌对内源性亲核试剂的高敏感性而产生的毒性(Q-TOX)，以促进儿茶酚氧化为相应的邻醌。除了无任何毒性的5-(半胱氨酸-S-基)单共轭物3外，所有化合物均产生ROS-TOX，在酪氨酸酶存在的情况下ROS-TOX增强，这表明生成的邻醌（或邻醌硫醚）物种可通过其半醌自由基进入氧化还原循环，导致活性氧的形成。毒性的顺序为HHMA≈1≈2≈5>>7>DA≈4>10>6>8。相反，即使在酪氨酸酶存在的情况下，也未证明醌与细胞亲核试剂结合产生的Q-TOX。最后，考虑到几种不同的途径可能导致摇头丸的总体毒性，并且HHMA和儿茶酚硫醚共轭物1-5尚未被明确确定为摇头丸的体内有毒代谢物，可以认为这些化合物可能通过产生活性氧的氧化还原活性醌类中心的效率参与该药物的毒性作用。
