Antimicrobial, antibiotic potentiating activity and phytochemical profile of essential oils from exotic and endemic medicinal plants of Mauritius

The aim of this study was to evaluate the antimicrobial properties of essential oils (EOs) isolated from 7 exotic and 2 endemic medicinal plants of Mauritius. Eighteen microorganisms (bacterial and fungal isolates) have been used to evaluate the antimicrobial potential of the EOs as well as their ability to potentiate conventional antibiotics. Significant antibacterial activities were recorded with low minimal inhibitory concentration for 8 of the EOs using the microbroth dilution assay except for Salvia officinalis, where the activity recorded was comparable to that of the antibiotics. The synergistic effect of the EOs of Pimenta dioica, Psiadia arguta and Piper betle were observed against Escherichia coli and Staphylococcus epidermidis when combined with gentamicin. The fungicidal and fungistatic effect of the EOs were observed among all the fungi irrespective of the family except for Trichophyton mentagrophytes. Forty three major compounds were identified using the gas chromatography-mass spectrometry method and predominantly composed of oxygenated monoterpenes at a dose ranging from 0.45% to 69.76%, while, in the case of P. dioica, the EO was predominantly composed of aromatic compounds at a dose of 89.22%. This study has provided key information on the antimicrobial property and phytochemical composition of some tropical medicinal plants from Mauritius.