Síntese e atividade antiestafilocócica do derivado 2-acetóxil-1, 4-naftoquinona

Abstract

The compound 2-acetoxy-1,4-naphthoquinone derivative (NQD), synthesized by one of us (Ferreira), was tested against six different bacterial species isolated from patients at Hospital Universitário Antônio Pedro (HUAP). The drug only exhibited activity on Gram-positive bacteria (zones of inhibition > 12 mm, for preliminary testings): Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis. Minimal inhibitory concentrations (MICs) and minimal bactericida/ concentrations (MBCs), for NQD on S. aureus strains, ranged from 16μ.g to 256μ.g!ml and from 64μ.g to 512μ.g!ml, respectively. On optical density ~ adings (560nm), NQD's inhibition kinetics increased directly with drug concentration rises. ln these experiments, 2 x MIC had a lytic action against oxacillin-sensitive strains. On viability determinations (CFU/ ml), the derivative also showed dose dependent kinetics, with very clear bactericida/ responses at 2 x MIC, on the strains sensitive to the beta-lactam. ln spite of NQD's slower activity, by comparison with clinicai antibiotics, these results stimulate us to modify the derivative structure, looking for better antibacterial actions.