Chemical composition, antibacterial and antibiofilm activities of essential oil from Tunisian Ephedra alata aerial parts

In the current work, we investigated the chemical composition, the antibacterial and antibiofilm properties of the essential oil (EO) from the aerial parts of Ephedra alata extracted by hydrodistillation. The main compounds identified by GC/MS were monoterpene hydrocarbons. Among these compounds, linalool (27.44%), a-terpinyl acetate (20.80%) and beta-pinene (9.87%) were the major constituents. The antibacterial activity was evaluated by determining the minimum inhibitory and bactericidal concentrations. The results showed a strong activity against both Gram negative and positive bacteria, particularly Pseudomonas aeruginosa and Micrococcus luteus (minimum inhibitory concentration MIC and minimum bactericidal concentration MBC = 1.25 mu g/mL). The antibiofilm activity was quantified using the crystal violet assay, and the results showed a high antibiofilm capacity against all tested strains and especially Pseudomonas aeruginosa, with a percentage of reduction up to 90%. The results are of interest for the potential use of E. alata essential oil to control pathogenic bacteria in their planktonic and/or their biofilm forms in medicine or the food industry.