Lippia sidoides essential oil against Candida auris and Candida albicans - A promising strategy for antifungal activity in the context of oral candidiasis.

内容摘要

The emergence of multidrug-resistant Candida highlights a pressing threat to global public health. To evaluate in vitro the antifungal activity, mechanism of action, drug association, and anti-biofilm effect of the essential oil of Lippia sidoides Cham. (EO-LS) against Candida albicans and Candida auris. EO-LS was extracted, and its chemical profile was determined by GC-MS. Assays were performed to determine the Minimum Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC), mechanism of action, drug interaction with nystatin and ketoconazole, time-kill kinetics, and biofilm inhibition by confocal microscopy. The compound exhibited fungicidal activity, with MIC and MFC values of 125&#x202f;&#xb5;g/mL against C. albicans and 62.5&#x202f;&#xb5;g/mL against C. auris. The exogenous ergosterol assay indicated that EO-LS exerts antifungal activity by interfering with fungal plasma membrane functions. The combination of EO-LS with ketoconazole demonstrated pharmacological synergism, while its combination with nystatin resulted in an antagonistic effect. EO-LS significantly inhibited fungal growth (p&#x202f;<&#x202f;0.005) and promoted a marked reduction of mature C. auris biofilm at a concentration of 125&#x202f;&#xb5;g/mL (p&#x202f;<&#x202f;0.0001), as confirmed by confocal microscopy imaging. The essential oil of Lippia sidoides exhibits antifungal activity against Candida spp., including C. auris, likely through an action on the cell membrane, and shows potential as an anti-biofilm agent with pharmacological synergism when combined with ketoconazole.