Antioxidant effects of angiotensin-converting enzyme (ACE) inhibitors: free radical and oxidant scavenging are sulfhydryl dependent, but lipid peroxidation is inhibited by both sulfhydryl- and nonsulfhydryl-containing ACE inhibitors.
With an assay that generates free radicals (FR) through photooxidation of dianisidine sensitized by riboflavin, 4 x 10(-5) M captopril, epicaptopril (SQ 14,534, captopril's stereoisomer), zofenopril, and fentiapril [all sulfhydryl (-SH)-containing angiotensin-converting enzyme (ACE) inhibitors] were shown effective scavengers of nonsuperoxide free radicals whereas non-SH ACE inhibitors were not. Captopril was a more effective FR scavenger at pH 5.0 than at pH 7.5. Captopril (2 x 10(-5) M) also scavenged the other toxic oxygen species hydrogen peroxide and singlet oxygen and inhibited microsomal lipid peroxidation. Finally, captopril reduced the amount of superoxide anion-radical detected after neutrophils in whole blood were activated with zymosan, probably by inhibiting leukocyte superoxide production.
Chopra
M
M
Department of Cardiology, Western Infirmary, Glasgow, Scotland.
Beswick
H
H
Clapperton
M
M
Dargie
H J
HJ
Smith
W E
WE
McMurray
J
J
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002216:Captopril / Q000494:pharmacology; D003962:Dianisidine / Q000494:pharmacology; D004347:Drug Interactions; D016166:Free Radical Scavengers; D005609:Free Radicals / Q000378:metabolism; D006098:Granulocytes / Q000187:drug effects / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D010777:Photochemistry; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism
D000806:Angiotensin-Converting Enzyme Inhibitors; D000975:Antioxidants; D016166:Free Radical Scavengers; D005609:Free Radicals; D013438:Sulfhydryl Compounds; D013481:Superoxides; D002216:Captopril; D003962:Dianisidine; D010100:Oxygen