title: N-acetylserotonin reduces lipopolysaccharide-induced lipid peroxidation in vitro more effectively than melatonin.
abstract: OBJECTIVE
  Bacterial lipopolysaccharide (LPS) causes lipid peroxidation (LPO). We have found that LPS induces LPO in vitro, in tissue homogenates in a concentration-dependent manner, the concentration of 400 µg/ml demonstrating the most efficient lipid damaging effect . Both melatonin and its precursor, N-acetylserotonin, must possess antioxidant activities, both in vivo or in vitro, however, following some claims, N-acetylserotonin is a more effective extra- and intracellular antioxidant than melatonin. The aim of our study was to compare the effects of melatonin and N-acetylserotonin on the LPS-induced LPO in vitro.
  
  
  METHODS
  Malondialdehyde (MDA) plus 4-hydroxyalkenal (4-HDA) concentrations were measured as the indices of induced membrane peroxidative damage in brain, liver and kidney homogenates. Both melatonin and N-acetylserotonin were used at increasing concentrations, starting from 0.01-5 mM, together with LPS at one concentration level of 400 µg/ml.
  
  
  RESULTS
  In all the examined tissues, LPS stimulated LPO, while both melatonin and N-acetylserotonin decreased LPS-stimulated LPO. Furthermore, the capacity of N-acetylserotonin reducing LPO was higher than that of melatonin.
  
  
  CONCLUSIONS
  The results of the reported study clearly indicate that N-acetylserotonin is a much stronger antioxidant in vitro than melatonin in terms of reducing oxidative damage to lipid membranes. However, it remains still unclear how the features relate to in vivo circumstances.
authors.affiliation: Department of Endocrine Disorders and Bone Metabolism, Medical University of Lodz, Poland.
authors.forename: Michal
authors.initials: M
authors.lastname: Stuss
authors.forename: Joanna A
authors.initials: JA
authors.lastname: Wiktorska
authors.forename: Ewa
authors.initials: E
authors.lastname: Sewerynek
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008550:Melatonin / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D008070:Lipopolysaccharides; D012701:Serotonin; D008315:Malondialdehyde; D008550:Melatonin; C006389:N-acetylserotonin