Antibacterial activity of essential oils from Brocchia cinerea, Artemisia campestris and Origanum vulgare growing in Algeria against antibiotic-resistant foodborne pathogens

This study aimed to evaluate the antibacterial activity of three Algerian medicinal plants (Brocchia cinerea, Artemisia campestris and Origanum vulgare) against multi-drug-resistant Gram-negative bacteria isolates from different food samples. Essential oils of the mentioned plants were extracted by hydro-distillation of the aerial parts. The chemical composition of the obtained oils was then determined using Gas Chromatography/Mass Spectrometry analysis. Moreover, the antibacterial activity was performed against different antibiotic-resistant bacterial species using the broth micro-dilution method. Gas Chromatography/Mass Spectrometry analysis showed a dominance of beta-thujone for the Brocchia cinerea essential oil. Whereas, the major components of Origanum vulgare and Artemisia campestris essential oils were carvacrol and thymol as well as 5(6 H)-benzocyclooctenone − 7,8- dihydro-8,8-dimethyl, 1,2,3,4,4a,9,10,10a-(trans- 4a,10a)-octahydro-9- oxophenanthrene, Germacrene D, respectively. The antibacterial activity results revealed that all the tested essential oils were active against the tested bacteria, including those resistant to last-resort antibiotics with minimum inhibitory concentrations ranging between 1.333 µg/mL and 170.72 µg/mL. In addition, Brocchia cinerea essential oil showed the best activity with the lowest minimum inhibitory concentration followed by Origanum vulgare and Artemisia campestris essential oils, respectively. Our study confirmed that the tested essential oils had an interesting activity against the tested antibiotic-resistant bacteria and may act as a potential source of natural effective antibacterial molecules that could be further investigated to help prevent bacterial proliferation in food products.