Atividade antibacteriana do óleo essencial Plectranthus amboinicus (Lour.) Spreng frente a cepas de bacilos anaeróbicos Gram negativos

Abstract

The anaerobic microorganisms are an important bacterial group involved in the aetiology of various infectious processes, being considered powerful opportunistic pathogens. Inside this group the gram negative bacteria associated with periodontal disease, abscess and wound infection stand out from the others. As an alternative for the treatment of these infections, the use of medicinal plants has gained strength, since many of these pathogens are proving resistant to usual antibacterial therapy. Therefore, this study aimed to investigate the in vitro antibacterial activity of essential oil (EO) of Plectranthus amboinicus (Lour.) Spreng against anaerobic Gram negative strains involved with those diseases. Thus, the EO was obtained by hydrodistillation and analized by gas chromatography mass spectrometry. The minimal inhibitory concentration was determined by the agar dilution method and the effects of their action on cell wall and cell mambrane was examined by atomic force microscopy. After analisys of the EO carvacrol (90.5%) was the major component. The rates of minimal inhibitory concentration and minimal bacterial concentration range respectively, between 64-128 p-g/ml and the bacterial kill curve showed a suggestive bacteriostatic and bactericidal effect. These results suggest that the P. amboinicus essential oil has activity against Gram negative anaerobes. These data corroborate with the use of this plant in the folk medicine for the treatment of infections caused by other Gram negative bacteria.