Antifungal activity, mode of action and anti-biofilm effects of Laurus nobilis Linnaeus essential oil against Candida spp.

Objective: The present study demonstrated the antifungal potential of the chemically characterized essential oil (EO) of Laurus nobilis L. (bay laurel) against Candida spp. biofilm adhesion and formation, and further established its mode of action on C albicans. Methods: L nobilis EO was obtained and tested for its minimum inhibitory and fungicidal concentrations (MIC/MFC) against Candida spp., as well as for interaction with cell wall biosynthesis and membrane ionic permeability. Then we evaluated its effects on the adhesion, formation, and reduction of 48 h C albicans biofilms. The EO phytochemical profile was determined by gas chromatography coupled to mass spectrometry (GC/MS). Results: The MIC and MFC values of the EO ranged from (250 to 500) mu g/mL. The MIC values increased in the presence of sorbitol (osmotic protector) and ergosterol, which indicates that the EO may affect cell wall biosynthesis and membrane ionic permeability, respectively. At 2 MIC the EO disrupted initial adhesion of C. albicans biofilms (p < 0.05) and affected biofilm formation with no difference compared to nystatin (p > 0.05). When applied for 1 min, every 811, for 24 h and 48 h, the EO reduced the amount of C. albicans mature biofilm with no difference in relation to nystatin (p > 0.05). The phytochemical analysis identified isoeugenol as the major compound (53.49%) in the sample. Conclusions: L nobilis ED has antifungal activity probably due to monoterpenes and sesquiterpenes in its composition. This EO may affect cell wall biosynthesis and membrane permeability, and showed deleterious effects against C. albicans biofilms. (C) 2016 Published by Elsevier Ltd.