Atividade antimicrobiana in vitro e in vivo das folhas de Plectranthus amboinicus frente cepas hospitalares de Staphylococcus aureus resistente à Meticilina

Abstract

The present study aimed to evaluate the efficacy of Plectranthus amboinicus (Lour.) Spreng against clinical isolates of MRSA. The in vitro antimicrobial activity of the essential oil of the hydroalcoholic extract (HE), the ethyl acetate fraction (EA) and its subfractions were determined by broth microdilution and bioautography against clinical isolates of MRSA. The chessboard microdilution method was used to evaluate in vitro drug combination studies. To induce abscess formation, bacterial suspensions were added to Citodex and inoculated subcutaneously into male Swiss mice. The treatment protocol consisted of 2 doses of HE, the EA fraction or vancomycin introduced intraperitoneally in mice 3 and 12 h after infection. Among the drugs studied, the most effective inhibitory effect against clinical strains was essential oil with minimal inhibitory concentration (MIC) ≥0.07% v / v, ethyl acetate fraction (F4) with MIC ≥ 0.25 mg / mL and the compound PA-1 MIC = 0.125 mg / mL. Plant samples were bacteriostatic at 2x and 4x MIC and bactericidal at 100 mg / ml. The EA and essential oil fraction showed synergism with vancomycin. A significant reduction in abscess volume, bacterial cell count in the abscess binders and inflammatory scores was observed in the HE and EA fraction treated groups. Samples were effective in treating the animals in a dose-dependent manner. The present study proved the efficacy of the fractions of P. amboinicus against MRSA using in vitro and in vivo assays.