Chemical fingerprints of Lamiaceae essential oils: targeting biofilm viability, biomass, metabolic activity, and membrane integrity.

This study examines the antibacterial and antibiofilm activities of essential oils from Thymus vulgaris, Rosmarinus officinalis, and Lavandula angustifolia. Chemical analysis identified carvacrol, linalool, and camphor as key constituents contributing to activity against E. coli, S. aureus, and P. aeruginosa. T. vulgaris oil, rich in phenolic and flavonoid content, showed the strongest efficacy. R. officinalis and L. angustifolia oils also demonstrated notable antimicrobial effects, reducing bacterial viability, biofilm biomass, and metabolic activity, although effectiveness varied with species and biofilm structure. T. vulgaris oil effectively removed E. coli and P. aeruginosa biofilms at 2 × MIC (log reduction 7) but was less effective against S. aureus (log reduction 1.7) at 2 × MIC. The activity of these oils may be associated with disruption of bacterial membranes, biofilm architecture, and induction of oxidative stress. Mammalian toxicity at 3 × MIC shows a low toxic profile for T. vulgaris and R. officinalis, but a high toxic profile for L. angustifolia. These findings highlight T. vulgaris and R. officinalis essential oils as promising antibacterial agents in terms of both efficacy and safety.