Caracterização e avaliação antifúngica do óleo essencial de Cinnamomum verum J.Presl contra isolados clínicos de Candida Albicans sensíveis e resistentes a fluconazol

Abstract

The number of invasive fungal infections has increased in recent years, with Candida species standing out as opportunistic yeasts and major causative agents of systemic mycoses. In this context, aromatic plants such as Cinnamomum verum J.Presl (true cinnamon) have attracted attention due to their antimicrobial properties. Therefore, this study aimed to characterize and determine the antifungal activities of Cinnamomum verum essential oil against Candida albicans. The essential oil was obtained by hydrodistillation using a Clevenger-type apparatus. Antifungal activity was evaluated by broth microdilution, and synergistic interactions were assessed using the checkerboard method. Antibiofilm activity and hemolytic effects were also determined. Additionally, the inhibition profile of virulence factors was analyzed through hydrolytic enzyme assays, and the mechanism of action was investigated using ergosterol and sorbitol assays. The essential oil showed a minimum inhibitory concentration (MIC) of 2.5 mg/mL against ATCC 90028 and other clinical isolates, and 1.25 mg/mL against the resistant clinical isolate C14. Checkerboard assays revealed an additive effect for the combination of amphotericin B and essential oil (FICI = 0.75 for ATCC 90028 and FICI = 1. 0 for C16). The combination of fluconazole and essential oil resulted in an additive effect for ATCC 90028 (FICI = 0.63) and a synergistic effect for C16 (FICI = 0.37). The essential oil inhibited biofilm adhesion similarly to fluconazole and amphotericin B but did not eradicate mature biofilms. Hemolytic activity was lower than that observed for the antifungals tested, with the essential oil showing the highest HC50 at 7.56 mg/mL. The oil modulated hydrolytic enzyme activity, particularly in strain ATCC 90028. Its mechanism of action was not associated with ergosterol or sorbitol pathways, suggesting interference with metabolic processes or cell wall integrity. These findings highlight the potential of natural products and their constituents in the search for new antimicrobial therapies.