title: Reaction kinetics of alpha-tocopheroxyl radical with biologically and pharmacologically active substances.
abstract: The alpha-tocopheroxyl radical (alpha TR.)generated in the reaction with 1,1-diphenyl-2-picrylhydrazyl in n-butanol decayed according to second-order kinetics with a rate constant k alpha = 3 x 10(3) M-1s-1 as determined by EPR spectroscopy. Various biologically and pharmacologically active substances like isoprenaline (ISO), epinephrine (EPI), histamine (HIS), stobadine (STO), nafazatrom (NAF) and Kampo C medicine (KMC) accelerated the decay rate of alpha TR(.). The whole process is formally a third-order reaction with the rate constants (in 10(9) M-2s-1): ks(ISO) = 1.28, ks(NAF) = 1.25, ks(EPI) = 0.6, ks(HIS) = 0.4, and ks(STO) = 0.1. In the kinetics of the reaction mechanism, bimolecular intermediates are assumed and the rate constants of their formation were determined.
authors.affiliation: Institute of Experimental Pharmacology, Slovak Academy of Sciences, Bratislava.
authors.forename: K
authors.initials: K
authors.lastname: Ondrias
authors.forename: V
authors.initials: V
authors.lastname: Misík
authors.forename: V
authors.initials: V
authors.lastname: Brezová
authors.forename: A
authors.initials: A
authors.lastname: Stasko
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D002243:Carbolines / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004837:Epinephrine / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry*; D006632:Histamine / Q000737:chemistry; D007545:Isoproterenol / Q000737:chemistry; D007700:Kinetics; D016859:Lipoxygenase Inhibitors / Q000737:chemistry; D008433:Mathematics; D008962:Models, Theoretical; D010084:Oxidation-Reduction; D011720:Pyrazoles / Q000737:chemistry; D047069:Pyrazolones; D013997:Time Factors; D014810:Vitamin E / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D002243:Carbolines; D005609:Free Radicals; D016859:Lipoxygenase Inhibitors; D011720:Pyrazoles; D047069:Pyrazolones; C066323:tocopheroxy radical; D014810:Vitamin E; D006632:Histamine; C018845:nafazatrom; D007545:Isoproterenol; C100106:dicarbine; D004837:Epinephrine