title: Selective targeting of an antioxidant to mitochondria.
abstract: Mitochondrial oxidative damage contributes significantly to a range of human disorders, including neurodegenerative diseases, ischaemia-reperfusion injury and ageing-associated dysfunction. To prevent this damage we have delivered a molecule containing the active antioxidant moiety of vitamin E to mitochondria. This was carried out by covalently coupling the antioxidant moiety to a lipophilic triphenylphosphonium cation. This mitochondrially targeted antioxidant, 2-[2-(triphenylphosphonio)ethyl]-3,4-dihydro-2, 5,7,8-tetramethyl-2H-1-benzopyran-6-ol bromide (TPPB), accumulated several-hundred fold within the mitochondrial matrix, driven by the organelle's large membrane potential. When cells were incubated with micromolar concentrations of TPPB, they accumulated millimolar concentrations within their mitochondria. The amount of TPPB taken up by mitochondria was approximately 80-fold greater than endogenous levels of vitamin E. Consequently the targeted derivative of vitamin E protected mitochondrial function from oxidative damage far more effectively than vitamin E itself. The mitochondrially targeted antioxidant TPPB has potential as an antioxidant therapy for disorders involving mitochondrial oxidative damage. It also suggests a new family of mitochondrially targeted antioxidants, redox-active and pharmacologically active molecules designed to prevent damage or manipulate mitochondrial function.
authors.affiliation: Department of Chemistry, University of Otago, Dunedin, New Zealand.
authors.forename: R A
authors.initials: RA
authors.lastname: Smith
authors.forename: C M
authors.initials: CM
authors.lastname: Porteous
authors.forename: C V
authors.initials: CV
authors.lastname: Coulter
authors.forename: M P
authors.initials: MP
authors.lastname: Murphy
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology*; D001578:Benzopyrans / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology*; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D006801:Humans; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D015227:Lipid Peroxidation / Q000187:drug effects; D008564:Membrane Potentials; D008930:Mitochondria, Liver / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000493:pharmacokinetics / Q000494:pharmacology*
chemical_list: C121197:2-(2-(triphenylphosphonio)ethyl)-3,4-dihydro-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol bromide; D000975:Antioxidants; D001578:Benzopyrans; D014810:Vitamin E; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone