Antioxidant Effect of Carnosine and Carnosine Dinitrosyl Iron Complexes under the Conditions Modeling Peroxidation of Biomolecules

The antioxidant activity of carnosine and of carnosine dinitrosyl iron complexes (DNICs) was studied. A system with metmyoglobin (metMb) or hemin in combination with tert-butyl hydroperoxide (t-BOOH) was used as an experimental model. Using the luminol-dependent chemiluminescence method, it was shown that carnosine and carnosine DNICs effectively diminished the level of prooxidants formed by the interaction of heme groups with t-BOOH. In addition, carnosine and carnosine DNICs inhibited the formation of diene conjugates arising during the oxidation of arachidonic acid in the metMb–t-BOOH system. In the reaction systems used, the antioxidant effect of carnosine DNICs was higher than that of carnosine. The antioxidant effect of carnosine also depended on the presence of bivalent iron ions added at a concentration equivalent to their content in DNICs. These results show that the insertion of carnosine as a ligand to nitrosyl iron complexes enhances its antioxidant properties.