Kinetic and theoretical study on peroxynitrite decomposition catalyzed by iron porphyrins

Abstract

Peroxynitrite is a potent oxidant in vivo which can result in serious diseases such as cardiopathy, acute inflammation and even cancer. Iron porphyrins have been shown to catalyze the efficient decomposition of peroxynitrite and are therefore important to detoxify the cytotoxic oxidant as therapeutic agents. A kinetic and theoretical study on peroxynitrite decomposition catalyzed by iron porphyrins is carried on in order to search and synthesize more effective scavengers of peroxynitrite. Kinetic experiments and quantum chemistry calculations were applied to iron porphyrins with different substituents for catalyzing peroxynitrite decay. Kinetic experiments suggested that the catalytic ability of iron porphyrins for peroxynitrite decomposition were dependent on the type and location of substituents on the porphyrin rings. Density functional calculations further reveal that the variation of substituent leads to a difference in structure-related quantum chemical descriptors including charges of central metal ion, energy of the highest occupied molecular orbital and energy of the lowest unoccupied molecular orbital.