The influence of calcium channel blockers on superoxide anions.
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.
Shridi
F
F
Department of Pharmacology, Copernicus Academy of Medicine, Cracow, Poland.
Robak
J
J
D000818:Animals; D000838:Anions / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004110:Diltiazem / Q000494:pharmacology; D005275:Fendiline / Q000494:pharmacology; D005609:Free Radicals; D066298:In Vitro Techniques; D008862:Microsomes, Liver / Q000201:enzymology; D009543:Nifedipine / Q000494:pharmacology; D010084:Oxidation-Reduction; D051381:Rats; D013481:Superoxides / Q000378:metabolism*; D014700:Verapamil / Q000494:pharmacology; D014969:Xanthine Oxidase / Q000378:metabolism
D000838:Anions; D002121:Calcium Channel Blockers; D005609:Free Radicals; D013481:Superoxides; D014700:Verapamil; D014969:Xanthine Oxidase; D004110:Diltiazem; D009543:Nifedipine; D005275:Fendiline