Antibacterial and antibiofilm activities of Laurus nobilis L. essential oil against Staphylococcus aureus strains associated with oral infections

Abstract

Background: Laurus nobilis L. is an aromatic herb with relevant medicinal properties due to its important chemical composition and its potential therapeutic effects. In this study, we investigate the chemical composition, the antibacterial and the antibiofilms activities of Tunisian L. nobilis L. essential oils against clinical Staphylococcus aureus strains.

Methods: The chemical composition of L. nobilis L. essential oils was analysed by Gas Chromatography-Mass Spectrometry (GC-MS). The antibacterial activity of L. nobilis L. essential oils was evaluated in vitro against oral S. aureus (n=21) strains using broth microdilution method. The antibiofilm activity was assessed via Crystal Violet staining and MTT assays.

Results: Our results revealed that GC-MS assay exhibited 1.8-Cineole, methyl eugenol and α-terpinyl acetate as the major compounds in the essential oils. Moreover, the essential oil from Sousse exhibited the best bactericidal activity (MICs values ranged from 3.91 to 15.62mgm^-1). Furthermore, this oil showed a strong biofilm inhibition effect above 70%, from a low sub-inhibitory concentration (1/16×MIC). MTT assay revealed that both essential oils displayed an excellent antibiofilm activity with eradication percentages ranging from 79.6±2.27 to 95.2±0.56.

Conclusion: Our finding demonstrated that L. nobilis L. essential oils are able to inhibit oral S. aureus strains with important antibiofilm efficacy. It could have a promising role in the prevention of oral diseases.

Keywords: Activité anti-staphylococcique; Activité antibiofilm; Anti-staphylococcal activity; Antibiofilm activity; CG–SM; Essential oil; GC–MS analysis; Huile essentielle; Laurus nobilis L..