NO-donating and hemolytic activity of tetranitrosyl iron complexes with ligands of the 2-mercaptopyridine series

The NO-donating and hemolytic activity of the binuclear tetranitrosyl iron complexes (TNIC) with thiolate ligands of the composition [Fe2(SR)2(NO)4], where R is pyridin-2-yl and 5-nitropyridin-2-yl, was studied. The NO-donating and hemolytic activities of the com- plex with the nitrosubstituted ligand are approximately two and three times higher than the corresponding characteristics of the complex with unsubstituted 2-mercaptopyridine, respectively. Symbate changes in these parameters confirm the conclusion made earlier on the peroxynitrite-dependent mechanism of erythrocyte hemolysis under the action of TNIC. The NO-donating activity of TNIC with ligands of the 2-mercaptopyridine series, unlike the previously studied complexes containing thioderivatives of other nitrogenous heterocycles as S-ligands, did not decrease with an increase in the concentration of erythrocytes. This allows one to consider them as promising NO-donating substances for the preparation of pharma- cological remedies.