N-acetylserotonin reduces lipopolysaccharide-induced lipid peroxidation in vitro more effectively than melatonin.
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.
Stuss
Michal
M
Department of Endocrine Disorders and Bone Metabolism, Medical University of Lodz, Poland.
Wiktorska
Joanna A
JA
Sewerynek
Ewa
E
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
D008070:Lipopolysaccharides; D012701:Serotonin; D008315:Malondialdehyde; D008550:Melatonin; C006389:N-acetylserotonin