Abstract
Harmine was <i>in situ</i> UV-irradiated in the presence of 5,5-dimethyl-1-pyrroline-<i>N</i>-oxide (DMPO), α-phenyl-<i>N-tert</i>-butyl nitrone (PBN), or α-(4-pyridyl-1-oxide) <i>N-tert</i>-butyl nitrone (4-POBN) as spin traps and observed by electron spin resonance (ESR) spectroscopy. The superoxide radical (O<sub>2</sub>•<sup>-</sup>) was detected as the corresponding DMPO, PBN, or 4-POBN spin adduct in dimethylsulfoxide (DMSO) or acetonitrile solution. The detection of these spin adducts was prevented by the addition of superoxide dismutase (SOD) to the solution. Also, the O<sub>2</sub>•<sup>-</sup> adduct formation was inhibited by the addition of antioxidants as cysteine methyl ester or ascorbic acid, in a dose-dependent manner. The studies carried out in aqueous buffered solution did not allow superoxide radical adduct detection. In the presence of DMPO as a spin trap, the DMPO–OH spin adduct was detected. On the other hand, classical scavengers of the hydroxyl radical such as mannitol or glycerol abolished DMPO–OH spin adduct detection. Other scavengers such as ethanol, DMSO, or sodium azide inhibited the trapping of hydroxyl radicals and resulted in the formation of new radical adducts. No PBN or 4-POBN spin adducts were detected in aqueous solution. The origin of the hydroxyl radical is discussed.
PDF Article
More Like This
Cited By
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.
Contact your librarian or system administrator
or
Login to access Optica Member Subscription