HYDROXYL RADICAL FORMATION RESULTING FROM THE INTERACTION OF NITRIC-OXIDE AND HYDROGEN-PEROXIDE

The highly reactive and cytotoxic hydroxyl radical ((OH)-O-.) was foun d by electrochemical detection to be produced in reactions involving h ydrogen peroxide (H2O2) and the nitric oxide ((NO)-N-.) donor diethyla mine-(NO)-N-. complex. Using aromatic hydroxylation of salicylate as a specific indicator of (OH)-O-., three salicylate hydroxylation produc ts were identified; catechol, 2,3- and 2,5-dihydroxybenzoic acid. Four additional compounds were detected but not identified. The interactio ns of H2O2 and (NO)-N-. represent a biologically feasible reaction mec hanism that can account for (OH)-O-.-induced damage in cellular enviro nments where transition metal ions are unavailable for participation i n the superoxide-mediated Fenton reaction. The ability of the (NO)-N-. /H2O2 complex to generate (OH)-O-. independently of iron or other tran sition metals provides a new focus for studies concerned with the orig in of tissue-specific damage caused by oxygen-derived species. (C) 199 8 Elsevier Science B.V.