Skip to main content

Photosensitization by Harmine: An ESR Spin Trapping Study on the Generation of the Superoxide Anion Radical

Buy Article:

$29.00 plus tax (Refund Policy)


Harmine was in situ UV-irradiated in the presence of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), α-phenyl-N-tert-butyl nitrone (PBN), or α-(4-pyridyl-1-oxide) N-tert-butyl nitrone (4-POBN) as spin traps and observed by electron spin resonance (ESR) spectroscopy. The superoxide radical (O2-) 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 O2- 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.

Keywords: ESR; Harmine; Photosensitizer; Spin trapping; Superoxide

Document Type: Research Article


Affiliations: Departamento de Química-Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco 28049 Madrid, Spain

Publication date: November 1, 1996

More about this publication?

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more