An electron paramagnetic resonance study of the interactions between the adriamycin semiquinone, hydrogen peroxide, iron-chelators, and radical scavengers.
Anaerobic reduction of hydrogen peroxide in a xanthine/xanthine oxidase system by adriamycin semiquinone in the presence of chelators and radical scavengers was investigated by direct electron paramagnetic resonance and spin trapping techniques. Under these conditions, adriamycin semiquinone appears to react with hydrogen peroxide forming the hydroxyl radical in the presence of chelators such as ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid. In the absence of chelators, a related, but unknown oxidant is formed. In the presence of desferrioxamine, adriamycin semiquinone does not disappear in the presence of hydrogen peroxide at a detectable rate. The presence of adventitious iron is therefore implicated during adriamycin semiquinone-catalyzed reduction of hydrogen peroxide. Formation of alpha-hydroxyethyl radical and carbon dioxide radical anion from ethanol and formate, respectively, was detected by spin trapping. Both the hydroxyl radical and the related oxidant react with these scavengers, forming the corresponding radical. In the presence of scavengers from which reducing radicals are formed, the rate of consumption of hydrogen peroxide in this system is increased. This result can be explained by a radical-driven Fenton reaction.
Kalyanaraman
B
B
Department of Radiology, Medical College of Wisconsin, Milwaukee 53226.
Morehouse
K M
KM
Mason
R P
RP
D002614:Chelating Agents; D003676:Deferoxamine; D004317:Doxorubicin / Q000031:analogs & derivatives* / Q000737:chemistry; D004492:Edetic Acid; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D016166:Free Radical Scavengers; D005609:Free Radicals; D006861:Hydrogen Peroxide; D007501:Iron; D007700:Kinetics; D004369:Pentetic Acid
D002614:Chelating Agents; D016166:Free Radical Scavengers; D005609:Free Radicals; C024703:adriamycin semiquinone radicals; D004369:Pentetic Acid; D004317:Doxorubicin; D004492:Edetic Acid; D006861:Hydrogen Peroxide; D007501:Iron; D003676:Deferoxamine