Open Access6‐Hydroxymelatonin protects against quinolinic‐acid‐induced oxidative neurotoxicity in the rat hippocampus
Author(s) -
Maharaj D. S.,
Maharaj H.,
Antunes E. M.,
Maree D. M.,
Nyokong T.,
Glass B. D.,
Daya S.
Publication year - 2005
Publication title -
journal of pharmacy and pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 118
eISSN - 2042-7158
pISSN - 0022-3573
DOI - 10.1211/0022357056424
Subject(s) - neurotoxicity , quinolinic acid , singlet oxygen , neuroprotection , free radical scavenger , chemistry , superoxide , in vivo , metabolite , pharmacology , antioxidant , biochemistry , oxygen , medicine , tryptophan , biology , organic chemistry , toxicity , enzyme , microbiology and biotechnology , amino acid
Melatonin, a naturally occuring chemical mediator, although assigned a diverse range of functions, has attracted interest because of its ability to function as a free radical scavenger. Its major hepatic metabolite and photoproduct, 6‐hydroxymelatonin (6‐OHM), also shares this property. Since singlet oxygen and quinolinic acid (QUIN) are critically involved in the pathology of neurotoxicity, the objective of this study was to investigate the ability of 6‐OHM to scavenge singlet oxygen and evaluate its ability to scavenge superoxide anions and reduce QUIN‐induced neurotoxicity in the hippocampus in‐vivo. The results show that 6‐OHM is an efficient inhibitor of singlet oxygen formation as indicated by the rate constants and quantum yields reported for 6‐OHM and zinc phthalo‐cyanine (ZnPc), respectively. 6‐OHM, appears to reduce QUIN‐induced superoxide anion generation in the hippocampus, which provides some evidence of the neuroprotective effects of 6‐OHM.