6-Hydroxymelatonin protects against quinolinic-acid-induced oxidative neurotoxicity in the rat hippocampus.
Melatonin, a naturally occurring 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 phthalocyanine (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.
Maharaj
D S
DS
Division of Pharmacology, Faculty of Pharmacy, Rhodes University, Grahamstown, 6140, South Africa.
Maharaj
H
H
Antunes
E M
EM
Maree
D M
DM
Nyokong
T
T
Glass
B D
BD
Daya
S
S
D000818:Animals; D002316:Cardiotonic Agents; D016166:Free Radical Scavengers; D006624:Hippocampus / Q000187:drug effects* / Q000473:pathology*; D008297:Male; D008550:Melatonin / Q000031:analogs & derivatives; D018696:Neuroprotective Agents; D018384:Oxidative Stress; D017378:Quinolinic Acid / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar
D002316:Cardiotonic Agents; D016166:Free Radical Scavengers; D018696:Neuroprotective Agents; D017378:Quinolinic Acid; D008550:Melatonin; C012365:6-hydroxymelatonin