Medical College of Wisconsin
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ESR detection of free radical intermediates during autoxidation of 5-hydroxyprimaquine. Free Radic Res Commun 1990;9(3-6):383-9 PMID: 2167276

Pubmed ID



Autoxidation of 5-hydroxyprimaquine, a putative metabolite of the antimalarial primaquine, was studied by oxygen consumption and ESR spectroscopy. 5-Hydroxyprimaquine underwent fast autoxidation under mild conditions (pH 7.4-8.5, 25 degrees C, and presence of 1 mM diethylenetriamine pentaacetic acid); each mol of the drug consumed 0.75 mol of oxygen and formed 0.5 mol of hydrogen peroxide. Direct-ESR experiments demonstrated that 5-hydroxyprimaquine autoxidation was accompanied by generation of a drug-derived free radical that is oxygen sensitive. Generation of hydroxyl radical was also established by spin-trapping experiments in the presence of 5,5-dimethyl-1-pyrroline N-oxide. The effect of antioxidant enzymes on hydroxyl radical adduct yield and analysis of autoxidation stoichiometry suggest that the main route for hydroxyl radical generation is the iron-catalyzed reaction between the drug-derived free radical and hydrogen peroxide.

Author List

Vasquez-Vivar J, Augusto O


Jeannette M. Vasquez-Vivar PhD Professor in the Biophysics department at Medical College of Wisconsin


2-s2.0-0025013036   5 Citations

MESH terms used to index this publication - Major topics in bold

Cyclic N-Oxides
Electron Spin Resonance Spectroscopy
Free Radicals
Hydroxyl Radical
Oxygen Consumption
Spin Labels
jenkins-FCD Prod-353 9ccd8489072cb19f5b9f808bb23ed672c582f41e