Synergistic effects of Thymus vulgaris essential oil in combination with antifungal agents and inhibition of virulence factors of Candida albicans

BLANC, ALAN; SORTINO, MAXIMILIANO; BUTASSI, ESTEFANÍA; SVETAZ, LAURA

Mar del Plata

Congreso; Reunión Anual de Sociedades de Biociencias - Reunión Conjunta SAIC SAB AAFE AACYTAL 2023; 2023

Sociedad Argentina de Biología

The aim of this study was to evaluate the antifungal activity of a mixture of thyme essential oil (ThyEO) and posaconazole (PSZ) and its capacity to inhibit virulence factors of Candida albicans. Materials and Methods: Minimum inhibitory concentration and minimum fungicidal concentration were evaluated using the microbroth dilution assay. Microdilution checkerboard assay was used to assess interactions. Ergosterol and methylene blue assays were used to detect effects on fungal membrane, while the sorbitol assay was used to detect effects on fungal cell wall. Inhibition of yeast virulence factors (adherence to epithelial cells, germ tube and pseudomycelium formation, secretion of hydrolytic enzymes, and biofilm formation) was assessed using previously reported methods. Results: the combination ThyEO/PSZ (31.25/0.0039 µg/ml) showed partial synergism against C. albicans strains. Furthermore, this mixture was fungicidal. ThyEO/PSZ, its components alone, and thymol have been shown to disrupt the fungal cytoplasmic membrane, increasing its permeability. At sub-inhibitory concentrations, ThyEO/PSZ significantly decreased the ability of C. albicans to adhere to buccal epithelial cells. ThyEO/PSZ, ThyEO and PSZ were able to reduce the pseudomycelium production of C. albicans while thymol completely inhibited its formation. ThyEO/PSZ, its components, and thymol inhibited biofilm formation and preformed biofilms of C. albicans. For the assays, means and standard deviations were determined. Differences between treatment groups were analyzed using ANOVA, Kruskall-Wallis, and Dunn tests; p-values