title: Formation of the semiquinone anion radical from tert-butylquinone and from tert-butylhydroquinone in rat liver microsomes.
abstract: The tert-butylsemiquinone anion radical is formed from tert-butylhydroquinone and from tert-butylquinone in rat liver microsomes. In the presence of oxygen, the quinone and, less extensively, the hydroquinone induce excess production of superoxide in microsomes. It is concluded that autoxidation of the semiquinone formed from the quinone by microsomal enzyme activity is responsible for superoxide formation and that the hydroquinone enters the redox cycle via autoxidation. tert-Butylquinone induces injury of the hepatocyte plasma membrane. tert-Butylhydroquinone and tert-butylquinone are metabolites of the antioxidant butylated hydroxyanisole. The semiquinone-dependent superoxide formation may contribute to the toxic actions of butylated hydroxyanisole.
authors.affiliation: Institute of Physical and Theoretical Chemistry, Free University of Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Bergmann
authors.forename: J K
authors.initials: JK
authors.lastname: Dohrmann
authors.forename: R
authors.initials: R
authors.lastname: Kahl
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D016227:Benzoquinones / Q000378:metabolism* / Q000633:toxicity; D002083:Butylated Hydroxyanisole / Q000378:metabolism / Q000633:toxicity; D004578:Electron Spin Resonance Spectroscopy; D006873:Hydroquinones / Q000378:metabolism* / Q000633:toxicity; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D009153:Mutagens / Q000633:toxicity; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains; D013481:Superoxides / Q000032:analysis
chemical_list: D000975:Antioxidants; D016227:Benzoquinones; D006873:Hydroquinones; D009153:Mutagens; D013481:Superoxides; D002083:Butylated Hydroxyanisole; C018855:2-tert-butylhydroquinone; C051290:2-tert-butyl-4-quinone