title: Reductive activation and thiol reactivity of benzazolo[3,2-a]quinolinium salts.
abstract: Derivatives of benzazolo[3,2-a]quinolium salts (QSDs) are reductively activated by the enzymatic reducing agents hypoxanthine (or xanthine)/xanthine oxidase and NADH dehydrogenase as evidenced by the increase in rates of ferricytochrome c (Cyt(III)c) reduction and oxygen consumption, respectively. No correlation between Michaelis-Menten parameters and QSDs redox potentials was found regarding anaerobic or aerobic Cyt(III)c reduction, although maximum rates were observed for nitro-containing QSDs. However, oxygen consumption rates correlate with QSDs redox potentials when NADH dehydrogenase is used as reducing agent. QSDs bind covalently to bovine serum albumin (BSA) under anaerobic conditions, in the presence, and less in the absence, of HX/XO and only if the nitro group is present at the QSD. QSDs react with glutathione (GSH) in the presence of HX/XO but not in its absence, under anaerobic conditions. The amount of reacted GSH increases, and the relative amount of GSSG formed decreases, with an increase in the QSD reduction potential, thus indicating that GSH reacts with reduced nitro-containing QSDs mainly in a manner which does not involve the production of GSSG, presumably, through the formation of the nitroso-QSD-GSH conjugate. QSDs are, thus, novel nitro-containing heterocyclic compounds which could be bioreductively activated to react with oxygen and thiols.
authors.affiliation: Department of Chemistry, University of Puerto Rico at Humacao, Humacao, PR 00791, USA. ae_alegria@webmail.uprh.edu
authors.forename: Antonio E
authors.initials: AE
authors.lastname: Alegria
authors.forename: Wilmarie
authors.initials: W
authors.lastname: Flores
authors.forename: Emelyn
authors.initials: E
authors.lastname: Cordones
authors.forename: Lizmarie
authors.initials: L
authors.lastname: Rivera
authors.forename: Pedro
authors.initials: P
authors.lastname: Sanchez-Cruz
authors.forename: Marisol
authors.initials: M
authors.lastname: Cordero
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Cox
mesh_terms: D000818:Animals; D002417:Cattle; D007700:Kinetics; D009245:NADH Dehydrogenase / Q000378:metabolism; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D011485:Protein Binding; D011806:Quinolinium Compounds / Q000737:chemistry*; D019163:Reducing Agents / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D019820:Xanthine / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D011806:Quinolinium Compounds; D019163:Reducing Agents; D013438:Sulfhydryl Compounds; D019820:Xanthine; D012710:Serum Albumin, Bovine; C038668:3-nitrobenzothiazolo(3,2-a)quinolinium; D014969:Xanthine Oxidase; D009245:NADH Dehydrogenase