Carvacrol with ARO1 repression synergistically alters Candida albicans mitochondrial integrity, energy metabolism, membrane ultrastructure, and function

Among Candida species, Candida albicans is the leading cause of candidemia and invasive candidiasis, which can cause morbidity and mortality in immunocompromised patients. Fungi have developed resistance to the few existing antifungal drugs, which are limited in efficacy and mechanistic diversity, emphasizing the urgent need for novel antifungals and combination therapies. Developing novel antifungals is more challenging than developing antibacterial agents, since eukaryotic fungi share components and metabolism with human cells, making the discovery of compounds with low cytotoxicity difficult. Phenolic compounds from plant-based essential oils with broad-spectrum antifungal activity and minimal cytotoxicity to humans, such as carvacrol, are regaining interest as antifungals. This study investigates the combined impact of carvacrol treatment and conditional repression of ARO1 , a key enzyme of the shikimate pathway, which synergistically disrupts metabolic activity, mitochondrial function, intracellular adenosine triphosphate levels, causes oxidative stress, and perturbs mitochondrial and plasma membrane potentials, as visualized by altered cell membrane and wall ultrastructure in Candida albicans . These findings indicate a potential strategy for combination therapy to address antifungal resistance.