Detection of the spin adduct produced from CYPMPO and water decomposition radicals

Abstract

The oxygen radicals play a crucial role in biological oxidative damage. It is important to clarify behavior of hydroxyl and superoxide radicals, detection and quantification of these radicals are required. A new spin-trap agent CYPMPO (5-(2,2-dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1- pyrroline N-oxide) can spin-trap hydroxyl and superoxide radicals, and then produce hydroxyl and superoxide adducts, respectively. The ESR spectra of these adducts are assigned as different spectra. It is expected that hydroxyl and superoxide radicals can quantified by using CYPMPO, however, furthermore quantitative evaluation of kinetics and reactivity of CYPMPO are required. The oxygen radicals are also produced by water decomposition with irradiation. The behavior of these radicals shows useful information for understanding the indirect effect of irradiation.
In present work, the reactivities of CYPMPO toward a hydrated electron and a hydroxyl radical utilizing a pulse radiolysis system are investigated, and compared with DMPO (5,5-Dimethyl-1-pyrroline N-oxide) results. The oxygen radicals produced by gamma-ray irradiation are also discussed.