title: N-Acetylserotonin and 6-Hydroxymelatonin against Oxidative Stress: Implications for the Overall Protection Exerted by Melatonin.
abstract: The protection exerted by N-acetylserotonin (NAS) and 6-hydroxymelatonin (6OHM) against oxidative stress was investigated using the density functional theory. It was found that these compounds are better peroxyl radical scavengers than melatonin itself, Trolox, caffeine, or genistein both in lipid and aqueous solutions. The related kinetic data is provided for the first time. The solvent polarity influences not only the absolute reactivity of NAS and 6OHM toward peroxyl radicals, but also their relative scavenging activity. In addition, they both fully inhibit the oxidative effects of copper-ascorbate mixtures, and (•)OH production via the Haber-Weiss reaction, albeit the effects on the later are only partial. On the basis of comparisons with other melatonin-related compounds, it is proposed that the role of NAS and 6OHM on the overall protection exerted by melatonin against oxidative stress is mainly related to their free radical scavenging activities. Moreover, they increase such protection. The role of the phenol moiety on such activity is demonstrated.
authors.affiliation: †Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa. C. P. 09340, México D. F. México.
authors.forename: Ruslán
authors.initials: R
authors.lastname: Álvarez-Diduk
authors.affiliation: †Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa. C. P. 09340, México D. F. México.
authors.forename: Annia
authors.initials: A
authors.lastname: Galano
authors.affiliation: ‡Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, Texas 78229, United States.
authors.forename: Dun Xian
authors.initials: DX
authors.lastname: Tan
authors.affiliation: ‡Department of Cellular and Structural Biology, UT Health Science Center, San Antonio, Texas 78229, United States.
authors.forename: Russel J
authors.initials: RJ
authors.lastname: Reiter
mesh_terms: D003300:Copper / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000737:chemistry; D008550:Melatonin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects*; D010545:Peroxides / Q000737:chemistry; D012701:Serotonin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D016166:Free Radical Scavengers; D010545:Peroxides; D012997:Solvents; D014867:Water; C049375:perhydroxyl radical; D012701:Serotonin; D017665:Hydroxyl Radical; D003300:Copper; D008550:Melatonin; C006389:N-acetylserotonin; C012365:6-hydroxymelatonin