10. Inhibition of transition metal ion-catalysed
ascorbate oxidation and lipid peroxidation
by allopurinol and oxypurinol.
Ko KM, Godin DV.
Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British
Allopurinol and its metabolite oxypurinol
inhibited basal oxidation of ascorbate and exerted
comparable concentration-dependent inhibitory effects on the oxidation of ascorbate catalysed by cupric ion,
but the stimulation produced by ferric ion was affected minimally. UV spectral
analysis suggested the formation of an allopurinol-ascorbate-copper
ion complex. The oxidation of erythrocyte membrane lipids by ferric ion and
cupric ion-t-butylhydroperoxide was also inhibited by
allopurinol and oxypurinol,
by the metal chelators EDTA and uric acid, and by the
antioxidant butylated hydroxytoluene.
The metal chelating actions of allopurinol and oxypurinol may be relevant to their protective actions
against ischemia/reperfusion injury.