[Antioxidant effect of drugs used in cardiovascular therapy]

Oxidative stress is implicated in the pathogenesis of various cardiovascular disorders. The knowledge, characterisation and comparison of the different antioxidant properties of some cardiovascular drugs might lead to new therapeutic approaches. Blood constituents are biological products easier to obtain. Their oxidative damage is accepted to be involved in several pathogenic pathways such as atherogenesis. Blood products can be utilised as in vitro models of macromolecular and cellular oxidative damage. It is well known that transition metals catalyse the generation of more damaging reactive oxygen species. We studied the antioxidant effect of four beta-adrenergic blocking agents (pindolol, propranolol, atenolol and metoprolol) and of one calcium channel antagonist (nifedipine), on the plasma oxidative damage induced by copper. Lipid peroxidation was evaluated by measuring fluorescent substances. We added the drugs to the assay system, before and after the induction of peroxidation by copper, to elucidate their ability to prevent and/or block lipid peroxidation. We observed that pindolol, propranolol and nifedipine have antioxidant properties, in the assay system, when added 15 min before the addition of copper. This effect is demonstrated by the delay in initiation and decrease in formation of lipid peroxidation products. Nifedipine also has a remarkable chain breaking effect. We compared the drugs with ascorbic acid in their relative antioxidant effect: nifedipine > ascorbate > pindolol > propranolol.