Chemical Composition, Antibacterial, and Antioxidant Activities of L. angustifolia Essential Oil Against Human Pathogenic Clinical Bacterial Isolates

L. angustifolia is a perennial shrub native to the Mediterranean region with multiple medicinal properties. In this study, we report on the chemical composition of L. angustifolia essential oil (LEO), its antibacterial, antibiofilm, and antioxidant activities against ten clinical isolates. Chemical constituents of LEO were identified using Gas Chromatography-Mass Spectrometry (GC–MS). Its antibacterial activity was evaluated in vitro against Gram-positive and Gram-negative bacteria using disk diffusion and broth microdilution methods. A growth inhibition assay was performed to determine the bacterial growth spectrophotometrically. The antibiofilm activity was assessed using a Crystal Violet assay. Finally, the activities of oxidative stress indicators, including Superoxide dismutase (SOD) and Catalase (CAT), were evaluated. GC–MS findings of the essential oil revealed the predominance of Linalool as the major compound. Antimicrobial tests demonstrated activity against Acetobacter aceti, Acinetobacter baumannii, Enterococcus faecium, Escherichia coli, Methicillin-resistant Staphylococcus aureus, Proteus vulgaris, Klebsiella pneumonia, Staphylococcus aureus, Staphylococcus haemolyticus and Stenotrophomonas maltophilia. Furthermore, LEO modulated bacterial growth over time, inhibited biofilm formation and eradicated pre-formed ones. Additionally, LEO significantly decreased the activities of the antioxidant enzymes SOD and CAT. Our findings demonstrated the therapeutic potential of LEO against pathogenic strains and broad antibacterial efficacy.