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The influence of calcium channel blockers on superoxide anions
Abstract:
Four calcium channel blockers were tested from the point of view of their influence on enzymic lipid oxidation and on generation of superoxide anions. All the compounds were found to be antioxidants as tested by the inhibition of NADPH-stimulated malonaldehyde formation from lipids. IC50 values were 60 microM for nifedipine; 1.1 microM for verapamil; 1.4 microM for fendiline and 20.6 microM for diltiazem. Only nifedipine scavenged superoxide anions both in an enzymic (xanthine:xanthine oxidase) and non-enzymic (phenazine methosulphate:NADH) generating system. IC50 values for this inhibition were about 2.5 times higher than for inhibition of formation of malonaldehyde. Nifedipine inhibited also xanthine oxidase-mediated formation of uric acid.
Insights
Four calcium channel blockers demonstrated antioxidant properties by inhibiting lipid oxidation. Nifedipine uniquely scavenged superoxide anions, suggesting broader antioxidant potential beyond lipid peroxidation inhibition.
Area of Science:
- Biochemistry
- Pharmacology
- Oxidative Stress
Background:
- Calcium channel blockers (CCBs) are widely used cardiovascular drugs.
- Oxidative stress, implicated in various diseases, involves lipid peroxidation and superoxide anion generation.
- The antioxidant potential of CCBs beyond their primary pharmacological action is not fully elucidated.
Purpose of the Study:
- To investigate the antioxidant effects of four CCBs: nifedipine, verapamil, fendiline, and diltiazem.
- To assess their influence on enzymic lipid oxidation and superoxide anion generation.
- To compare their efficacy in inhibiting malonaldehyde formation and scavenging superoxide radicals.
Main Methods:
- Lipid peroxidation was assessed by measuring NADPH-stimulated malonaldehyde formation.
- Superoxide anion scavenging was evaluated using both enzymic (xanthine/xanthine oxidase) and non-enzymic (phenazine methosulphate/NADH) systems.
- Inhibition concentrations (IC50) were determined for each CCB in the tested assays.
Main Results:
- All four CCBs exhibited antioxidant activity by inhibiting lipid peroxidation, with varying IC50 values (nifedipine: 60 µM, verapamil: 1.1 µM, fendiline: 1.4 µM, diltiazem: 20.6 µM).
- Nifedipine was the only CCB that effectively scavenged superoxide anions in both tested systems.
- Nifedipine's IC50 for superoxide scavenging was approximately 2.5 times higher than for malonaldehyde formation inhibition.
- Nifedipine also inhibited xanthine oxidase-mediated uric acid formation.
Conclusions:
- CCBs possess antioxidant properties, acting as inhibitors of lipid peroxidation.
- Nifedipine demonstrates a dual antioxidant capacity, inhibiting both lipid peroxidation and scavenging superoxide anions.
- These findings suggest a potential role for nifedipine in mitigating oxidative stress, warranting further investigation.