title: Oxidative damage shifts from lipid peroxidation to thiol arylation by catechol-containing antioxidants.
abstract: Catechol-containing antioxidants are able to protect against lipid peroxidation by nonenzymatic scavenging of free radicals with their catechol moiety. During their antioxidant activity, catechol oxidation products such as semiquinone radicals and quinones are formed. These oxidation products of 4-methylcatechol inactivate the GSH-dependent protection against lipid peroxidation and the calcium sequestration in liver microsomes. This effect is probably due to arylation by oxidation products of 4-methylcatechol of free thiol groups of the enzymes responsible for the GSH-dependent protection and calcium sequestration, i.e. the free radical reductase and calcium ATPase. It is concluded that a catechol-containing antioxidant might shift radical damage from lipid peroxidation to sulfhydryl arylation.
authors.affiliation: Department of Pharmacology and Toxicology, Faculty of Medicine, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands. A.Boots@farmaco.unimaas.nl
authors.forename: Agnes W
authors.initials: AW
authors.lastname: Boots
authors.forename: Guido R M M
authors.initials: GR
authors.lastname: Haenen
authors.forename: Gertjan J M
authors.initials: GJ
authors.lastname: den Hartog
authors.forename: Aalt
authors.initials: A
authors.lastname: Bast
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D016227:Benzoquinones / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism; D002396:Catechols / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005033:Ethylmaleimide / Q000494:pharmacology; D005609:Free Radicals / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism*; D013439:Sulfhydryl Reagents / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D016227:Benzoquinones; D002396:Catechols; D005609:Free Radicals; D013438:Sulfhydryl Compounds; D013439:Sulfhydryl Reagents; C018599:4-methylcatechol; C088487:4-methyl-1,2-benzoquinone; D000252:Calcium-Transporting ATPases; D005978:Glutathione; D005033:Ethylmaleimide