Targeting skin-associated candida: antifungal efficacy of selected essential oils

Introduction: Candida spp. are commensal yeasts that inhabit the skin and mucous membranes and are the leading cause of invasive fungal infections (Lopes et al. 2024). Mucocutaneous candidiasis is a common condition, often treated with azoles and polyenes, which can cause side effects and promote resistance (Tortorano et al., 2021). Essential oils (EOs), natural compounds with antimicrobial activity, present a promising alternative due to their multi- targeted action, thereby reducing the likelihood of resistance (Zuzarte et al., 2011). Objective: To study the antimicrobial activity of three EOs – eucalyptus, lavender, and thyme – against two species of Candida (C. albicans and C. tropicalis). Conclusions: Eucalyptus, lavender, and thyme EOs presented antifungal activity against C. albicans and C. tropicalis. Thyme possessed the lowest MIC; the inhibition curves corroborated this result. All EOs showed anti-biofilm activity. The flow cytometry assay showed that all oils were able to damage yeast cells; thyme oil presented the highest percentages of dead and injured cells. Fluorescence microscopy supported flow cytometry findings, revealing live (green), injured (yellow), and dead (red) cells following EO exposure. Thyme EO was the one with the best antifungal activity. These promising results suggest EOs, especially thyme, can be applied to formulations to treat Candida-related skin infections.