Antioxidant and prooxidant action of nitric oxide donors and metabolites

It has been shown that various nitric oxide donors and metabolites have similar effects on lipid peroxidation in rat myocardium homogenate. The formation of malondialdehyde, a secondary product of lipid peroxidation, was inhibited in a dose-dependent manner by PAPA/NONO (a synthetic nitric oxide donor), S-nitrosoglutathione, nitrite, and nitroxyl anion. The inhibition of lipid peroxidation was provided most efficiently by the administration of dinitrosyl-iron complexes with dextran and PAPA/NONO. S-nitrosoglutathione also inhibited the destruction of coenzymes Q(9) and Q(10) during free radical oxidation of myocardium homogenate. Low-molecular-weight dinitrosyl iron complexes with cysteine also promoted lipid peroxidation, which is probably due to iron release during the destruction dinitrosyl iron complexes. It is likely that the antioxidant action of nitric oxide derivatives is related to the reduction of ferry forms of hemoproteins and interaction of nitric oxide with lipid radicals.