Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, Texas, USA.
Mini Rev Med Chem. 2013 Mar;13(3):373-84. doi: 10.2174/1389557511313030006.
Melatonin is an uncommonly widely distributed molecule. It is found throughout the plant and animal kingdoms, i.e., perhaps in every living organism. Within vertebrate organisms, melatonin also has an extremely wide distribution, seemingly being capable of entering every cell and all subcellular compartments. So-called morphophysiological barriers, e.g., the blood-brain barrier, are no impediment to the passage of melatonin and it has a multitude of confirmed functions. We have hypothesized that melatonin originally evolved as a free radical scavenger and during evolution it acquired other important and essential actions. Due to the multi-faceted actions of melatonin and its metabolites as direct free radical scavengers and indirect antioxidants, these agents have been used to abate oxidative damage in a diverse variety of experimental models where free radical destruction is a component. When compared with classic, better-known antioxidants, melatonin is better in terms of limiting destruction of intracellular macromolecules when the damage is a consequence of excessive oxygen or nitrogen-based toxic reactants. Considering the vast array of experimental data that has accumulated which documents melatonin's high efficacy and lack of, or minimal, toxicity over a very wide dose range, it is essential that the usefulness of this agent be more thoroughly tested at the clinical level. The findings from experimental models of numerous diseases overwhelming confirm that this indoleamine would likely have great benefit in aiding humans suffering with conditions that have as their basis tissue and molecular damage resulting from oxygen and nitrogen-based reactants.
褪黑素是一种分布非常广泛的分子。它存在于植物和动物王国中，即可能存在于每个生物体中。在脊椎动物中，褪黑素也有极其广泛的分布，似乎能够进入每个细胞和所有亚细胞区室。所谓的形态生理学屏障，例如血脑屏障，对褪黑素的通过没有阻碍，它具有许多已证实的功能。我们假设褪黑素最初是作为自由基清除剂进化而来的，在进化过程中它获得了其他重要和必需的作用。由于褪黑素及其代谢物作为直接自由基清除剂和间接抗氧化剂的多方面作用，这些物质已被用于减轻各种自由基破坏是其组成部分的实验模型中的氧化损伤。与经典的、更知名的抗氧化剂相比，当损伤是由于过量的氧或氮基毒性反应物引起时，褪黑素在限制细胞内大分子的破坏方面更有效。考虑到积累了大量证明褪黑素在非常宽的剂量范围内具有高效性、低毒性或最小毒性的实验数据，在临床水平上更彻底地测试这种药物的用途至关重要。许多疾病的实验模型的研究结果都证实，这种吲哚胺类物质很可能对因氧和氮基反应物导致的组织和分子损伤而患病的人类有很大的益处。
