GC-FID Analysis and Antibacterial Activity of the Calyptranthes concinna Essential Oil against MDR Bacterial Strains

Presently, results from a study carried out in this area using the essential oil from the Calyptranthes concinna species, a representative from the Myrtaceae family, are reported. The essential oil was obtained by hydrodistillation and gas chromatography coupled to mass spectrometry was used to identify its chemical constituents. Antibacterial activity was determined using the broth microdilution method, thus obtaining the Minimal Inhibitory Concentration (MIC) value, from which the subinhibitory concentration (MIC/8) was derived. The C. concinna essential oil presented antibacterial activity against both standard and multiresistant bacteria. In addition, the oil demonstrated an antibiotic activity potentiation against Staphylococcus aureus and Escherichia coli when in combination with the antibiotic gentamicin, reducing the MIC from 141.38 mu g/mL and 208.63 mu g/mL to 64 mu g/mL and 128 mu g/mL, respectively. Conclusions: Findings from the present study suggest this oil is promising in terms of its antimicrobial activity.