Protective effect of beta-carbolines and other antioxidants on lipid peroxidation due to hydrogen peroxide in rat brain homogenates

Tryptoline and pinoline are two beta -carbolines isolated from the nervous system of mammals. We investigated the ability of these compounds to preven t lipid peroxidation induced by hydrogen peroxide in rat brain homogenates. We also compared their effects with other known antioxidants including mel atonin, trolox and ascorbic acid. Lipid peroxidation was assessed by measur ing malonaldehyde (MDA) and 4-hydroxy-alkenals (4-HDA) concentrations in th e brain homogenates. Incubation with hydrogen peroxide (5 mM) increased MDA + 4-HDA levels, which were totally prevented by tryptoline, pinoline, mela tonin and trolox in a concentration-dependent manner. By contrast, higher M DA-4-HDA concentrations compared with control experiments were found after incubation with ascorbic acid, thus reflecting an increase of lipid peroxid ation induced by this compound. Although in vivo studies are needed, the da ta suggest that these beta -carbolines may be potential neuroprotective age nts because of their antioxidant activities. (C) 2000 Elsevier Science Irel and Ltd. All rights reserved.