Natural products eugenol and cinnamaldehyde as potential therapeutic alternatives against Candida auris infections.

Aims: Candida auris has been reported on all continents, becoming a global threat due to high levels of resistance to all antifungal classes. In addition, this pathogen has lower susceptibility to disinfectants used in hospitals, favoring its stay in such environments. Evaluate the action of eugenol and cinnamaldehyde against Candida auris.

Methods and results: The products were evaluated through sensitivity tests of broth microdilution, as well as their possible mechanisms of action using proteomic analysis. For microdilution was used 24 strains and for synergistic interactions was used 2 strains. Cytotoxicity of these products was verified in Vero cells. Eugenol and cinnamaldehyde showed fungicidal action at concentrations ranging from 31.25 to 250 µg/mL. Combinations of eugenol and cinnamaldehyde with itraconazole showed either antagonistic effects or no detectable interaction. No cytotoxicity was found for eugenol at the concentrations that caused yeast growth inhibition. On the other hand, cinnamaldehyde was cytotoxic at the same concentrations. According to proteomic analysis, the mechanism of action of eugenol and cinnamaldehyde is possibly related to the biosynthesis of ergosterol.

Conclusion: The present results suggest eugenol as a possible candidate for the development of formulations to treat infections caused by C. auris.