title: Antioxidant power of angiotensin-converting enzyme inhibitors in vitro.
abstract: OBJECTIVE
  There is controversy regarding the potential antioxidant effect of captopril, therefore this study was performed to compare the in vitro antioxidant power of captopril with other angiotensin-converting enzyme (ACE) inhibitors.
  
  
  METHODS
  Antioxidant power of captopril, enalapril, fosinopril, perindopril, quinapril and ramipril in aqueous solution was measured using the ferric reducing (antioxidant) power (FRAP) assay; captopril was also measured in ethanolic solution.
  
  
  RESULTS
  Only captopril showed significant antioxidant power, demonstrating a stoichiometric factor of 1.0 in this assay. Concentration-related antioxidant power was seen in both aqueous and ethanolic solutions.
  
  
  CONCLUSIONS
  Captopril shows antioxidant activity in vitro. This property could be relevant in vivo if captopril is concentrated in membranes, lipoproteins or at other important sites.
authors.affiliation: Department of Nursing & Health Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon.
authors.forename: I F
authors.initials: IF
authors.lastname: Benzie
authors.forename: B
authors.initials: B
authors.lastname: Tomlinson
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000032:analysis* / Q000494:pharmacology; D000975:Antioxidants / Q000008:administration & dosage / Q000032:analysis* / Q000494:pharmacology; D002216:Captopril / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology; D003124:Colorimetry / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004656:Enalapril / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology; D005290:Ferric Compounds / Q000737:chemistry / Q000378:metabolism; D005296:Ferrous Compounds / Q000737:chemistry / Q000378:metabolism; D017328:Fosinopril / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology; D007211:Indoles / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology; D007546:Isoquinolines / Q000008:administration & dosage / Q000032:analysis / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D020913:Perindopril; D000077583:Quinapril; D044005:Tetrahydroisoquinolines
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000975:Antioxidants; D005290:Ferric Compounds; D005296:Ferrous Compounds; D007211:Indoles; D007546:Isoquinolines; D044005:Tetrahydroisoquinolines; D004656:Enalapril; D002216:Captopril; D017328:Fosinopril; D000077583:Quinapril; D020913:Perindopril