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The prooxidant properties of captopril
D Lapenna1, S De Gioia, A Mezzetti
1Istituto di Fisiopatologia Medica, Università degli Studi "G. D'Announzio", Facolta' di Medicina e Chirurgia, Chieti, Italy.
Biochemical Pharmacology
|June 29, 1995
Summary
Captopril exhibits prooxidant effects with iron and copper, challenging its antioxidant classification. Its thiol group is key to iron chelation and copper reduction, influencing oxidative injury.
Area of Science:
- Biochemistry
- Medicinal Chemistry
- Toxicology
Background:
- Captopril, a thiol drug, has known metal-binding properties.
- Transition metals like iron and copper can induce oxidative stress.
- The prooxidant or antioxidant role of captopril in metal-induced oxidative injury requires clarification.
Purpose of the Study:
- To investigate the effects of captopril on iron- and copper-induced oxidative injury.
- To determine the role of captopril's thiol group in these processes.
- To evaluate captopril's potential prooxidant capacity in the presence of transition metals.
Main Methods:
- Deoxyribose oxidation assay was used to measure oxidative injury.
- Experiments involved iron(III) or copper(II) as oxidants.
- The role of ascorbate and pre-mixing with metals was assessed.
- Comparisons were made with reduced glutathione (GSH) and ramiprilat.
Main Results:
- Captopril enhanced iron-induced oxidation via 'malignant' chelation, independent of iron reduction.
- Captopril acted as a prooxidant with copper, involving both chelation and copper(II) to copper(I) reduction.
- GSH showed biphasic effects with copper, while ramiprilat had minimal impact.
Conclusions:
- Captopril is not solely an antioxidant drug.
- Its prooxidant capacity, mediated by transition metal interactions (chelation and reduction), is significant.
- These findings necessitate consideration of captopril's catalytic metal-related prooxidant effects in research and clinical settings.