Evaluation of the antifungal activity and mode of action of citral against Cladophialophora carrionii

Introduction: Cladophialophora carrionii is one of the most frequent etiologic agents of human chromoblastomycosis, a chronic cutaneous disease. Such fungal infections are difficult to treat and underlines the need for new antifungal agents. Citral is a monoterpene with known pharmacological properties, including antimi-crobial activity. Aims: To investigate the antifungal activity of citral against strains of C. carrionii. Methodology: The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) were determined by broth microdilution techniques. Citral was tested to evaluate its effects on C. carrionii mycelia growth and germination of fungal conidia. Next, it was investigated the possible citral action on cell walls (sorbitol assay) and cell membranes (ergosterol binding assay). Results: The MIC50 and MFC50 of citral were respectively 128 μg/mL and 512 μg/mL. The study shows that citral displayed in vitro antifungal potential against strains of C. carrionii, where it was capable of inhibiting both its mycelial growth and germination of conidia for this fungus, whilst affecting the structure of fungal cell membranes. Citral’s mechanism of action involves binding to ergosterol. Further study is needed to completely describe its effects before clinical use as a therapeutic antifungal agent.