title: Oxidative stress in Staphylococcus aureus associated to the cleavage of an isoxazolylnaphthoquinoneimine with antibacterial capacity.
abstract: Staphylococcus aureus was inhibited by exposure to 2-hydroxy-N-(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinone-4-imine (Q1). This compound was cleavaged in the presence of bacteria and an efflux of isoxazolamine was detected whereas in the S. aureus membrane and cytoplasm was observed an absorption band similar to that of the bencenoid ring. Non-viable bacteria showed intact Q1 intracellularly and in the membrane. Antistaphylococcus effect was associated to Q1 interaction with the respiratory chain, the oxidative metabolites were stimulated; there was cellular injury simultaneous to reduction of antibiotic molecule and efflux of isoxazolamine. The bacteria treated with Q1 increased its oxygen consumption and superoxide anion generation. Superoxide dismutase (SOD) production was stimulated, but it was principally extracellular in S. aureus. Escherichia coli, a species resistant to the antibiotic, did not reduce Q1 and showed lower superoxide anion generation; besides, there was an increase of intracellular SOD with extracellular decrease.
authors.affiliation: Departamento de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Argentina.
authors.forename: P M
authors.initials: PM
authors.lastname: Bogdanov
authors.forename: M M
authors.initials: MM
authors.lastname: Bertorello
authors.forename: I
authors.initials: I
authors.lastname: Albesa
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism* / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000378:metabolism; D007555:Isoxazoles / Q000378:metabolism* / Q000494:pharmacology*; D009284:Naphthols / Q000378:metabolism* / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000096:biosynthesis; D013481:Superoxides / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D007555:Isoxazoles; D009284:Naphthols; D013481:Superoxides; C070800:2-hydroxy-N-(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinone imine; D013482:Superoxide Dismutase