Effect of Aminophenol and Amino Acids Derivatives on the Level of Nitrosyl Radical and Its Active Forms <i>In Vitro</i>

The effect of aminophenol, amino acids and their derivatives on the level of •NO and its intermediates (•NO2, N2O3) in an aqueous aerobic media (pH = 7.4) was studied using nitroprusside as a •NO donor. It was found that the highest NOx scavenging activity is exhibited by 3-aminophenol (IC50 = 0.11 mM), 2-aminophenol (IC50 = 0.195 mM) and 4,6-di-tert-butyl-2-aminophenol (IC50 = 0.12 mM), standards: trolox (IC50 = 0.19 mM) and ascorbate (IC50 = 4.88 mM). Methylation of the OH group reduced the effectiveness of aminophenol. In the studied concentration range (0–70 mM), Tyr-Ala (IC50 = 5.0 mM) and β-Ala-His (IC50 = 35.0 mM) were more active than Phe-Ala (IC50 50 mM) and Gly-Gly (IC50 50 mM). Complexes Cu(Gly)2 and Cu(Gly-Gly)2 at low concentrations (0.05–0.5 mM) are 1.4–1.8 times more effective than Gly and Gly-Gly.