Hydroxyl radical formation resulting from the interaction of nitric oxide and hydrogen peroxide

Abstract

The highly reactive and cytotoxic hydroxyl radical ( ·OH) was found by electrochemical detection to be produced in reactions involving hydrogen peroxide (H 2O 2) and the nitric oxide ( · NO) donor diethylamine- · NO complex. Using aromatic hydroxylation of salicylate as a specific indicator of · OH , three salicylate hydroxylation products were identified; catechol, 2,3- and 2,5-dihydroxybenzoic acid. Four additional compounds were detected but not identified. The interactions of H 2O 2 and · NO represent a biologically feasible reaction mechanism that can account for · OH -induced damage in cellular environments where transition metal ions are unavailable for participation in the superoxide-mediated Fenton reaction. The ability of the · NO/H 2O 2 complex to generate · OH independently of iron or other transition metals provides a new focus for studies concerned with the origin of tissue-specific damage caused by oxygen-derived species.