title: The interaction of diamines and polyamines with the peroxidase-catalyzed metabolism of aromatic amines: a potential mechanism for the modulation of aniline toxicity.
abstract: Synthetic and biological amines such as ethylenediamine (EDA), spermine, and spermidine have not been previously investigated in free-radical biochemical systems involving aniline-based drugs or xenobiotics. We aimed to study the influence of polyamines in the modulation of aromatic amine radical metabolites in peroxidase-mediated free radical reactions. The aniline compounds tested caused a relatively low oxidation rate of glutathione in the presence of horseradish peroxidase (HRP), and H2O2; however, they demonstrated marked oxygen consumption when a polyamine molecule was present. Next, we characterized the free-radical products generated by these reactions using spin-trapping and electron paramagnetic resonance (EPR) spectrometry. Primary and secondary but not tertiary polyamines dose-dependently enhanced the N-centered radicals of different aniline compounds catalyzed by either HRP or myeloperoxidase, which we believe occurred via charge transfer intermediates and subsequent stabilization of aniline-derived radical species as suggested by isotopically labeled aniline. Aniline/peroxidase reaction product(s) were monitored at 435 nm by kinetic spectrophotometry in the presence and absence of a polyamine additive. Using gas chromatography-mass spectrometry, the dimerziation product of aniline, azobenzene, was significantly amplified when EDA was present. In conclusion, di- and poly-amines are capable of enhancing the formation of aromatic-amine-derived free radicals, a fact that is expected to have toxicological consequences.
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, Katz Group Centre for Pharmacy & Health Research, University of Alberta, Edmonton, AB, Canada. michail@ualberta.ca
authors.forename: Karim
authors.initials: K
authors.lastname: Michail
authors.forename: Naif
authors.initials: N
authors.lastname: Aljuhani
authors.forename: Arno G
authors.initials: AG
authors.lastname: Siraki
mesh_terms: D000588:Amines / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D000814:Aniline Compounds / Q000633:toxicity*; D002384:Catalysis; D003959:Diamines / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D005609:Free Radicals / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D010101:Oxygen Consumption / Q000502:physiology; D009195:Peroxidase / Q000378:metabolism*; D011073:Polyamines / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology
chemical_list: D000588:Amines; D000814:Aniline Compounds; D003959:Diamines; D005609:Free Radicals; D011073:Polyamines; D009195:Peroxidase; C023650:aniline