Estudo comparativo sobre a composição química, atividade antibacteriana e efeito sinérgico dos óleos essenciais de Croton tetradenius Baill. e c. pulegiodorus Baill. Contra isolados de Staphylococcus aureus

Abstract

Staphylococcus aureus has high clinical relevance for its ability to develop resistance mechanisms, so it is necessary to development of new forms of control of this microorganism. Therefore, for being sources of natural products, essential oils (OEs) are promising in the search for new bioactive compounds that can be used in health. O objective of this work was to analyze the chemical composition and antibacterial activity of Croton tetradenius Baill essential oil. (OECT) and Croton pulegiodorus Baill. (OECP) against S. aureus isolates and the synergistic effect with antibiotics conventional. For this, the OECT and OECP were extracted by hydrodistillation, quantitative analysis performed by gas chromatography coupled to the mass spectrometry (CG / MS) and qualitative analysis by gas chromatography with flame ionization detector (CG-DIC). Two strains were used standards (ATCC 700698 and 6538) and four clinical isolates (0A, 4B, 8B and 9B). The profile resistance of the strains was determined by the VITEK®2 system, and the ATCC 700698 and clinical isolate 0A showed a higher resistance profile. The activity antibacterial analysis of the oils was analyzed by disc-diffusion, microtiter and by growth curve. The synergistic effect of OEs with antibiotics (oxacillin, ampicillin and benzylpenicillin) was assessed using the checkerboard test. THE statistical analysis was determined by the area under the curve (ASC) of the curve test growth, using ANOVA test. OECT and OECP showed income 0.47 and 0.37% w / w, respectively. For the species C. tetradenius Baill. O most prevalent volatile component was p-cymene (28.35%), followed by camphor (18.29%) and α-felandrene (8.98%). For the species C. pulegiodorus, it was chrysantenyl transacetate (27.05%), α-terpinene (19.21%) and o-cymene (12.27%). O disk-diffusion assay showed that bacteria are sensitive to agents tested. The Minimum Inhibitory Concentration (MIC) in the presence of the OECT was 4,000 µg / mL, while for OECP it was 8,000 µg / mL, except for clinical isolate 4B. THE Minimum Bactericidal Concentration (CBM) for strains treated with OECT was 8,000 µg / mL, with the exception of isolates 8B and 0A (4,000 µg / mL). For the OECP all the strains showed a concentration above 8,000 µg / mL. The analysis of the growth revealed the ability of the OECT and OECP to delay the lag phase and reduce the log phase (p <0.001). OEs showed synergism between themselves and with tested antibiotics, especially when combined with OXA. Therefore, both C. tetradenius Baill. as for C. pulegiodorus Baill. showed antibacterial action against S. aureus strains, showing promising natural alternatives in the clinical therapy, even combined with antibiotics.