Potential of the β-Myrcene Rich Essential Oil from Astronium Urundeuva (M.Allemão) Engl. (Anacardiaceae) to Potentiate Fluconazole Activity and Inhibit Morphological Transition in Candida Species.

Background: In view of the increasing resistance of Candida species, it is necessary to explore alternative strategies. In this context, essential oils have emerged as promising options, among which the essential oil of Astronium urundeuva (M. Allemão) Engl. has shown potential, as it is traditionally used in folk medicine for the treatment of inflammation and multiple infections. Thus, the aim of this study was to evaluate the chemical profile, anti- Candida activity, and Fluconazole (FCZ) potentiating effect of the essential oil extracted from the leaves of A. urundeuva (EOAU) and its ability to inhibit the virulence mechanism in Candida species.

Methods: The essential oil was obtained via hydrodistillation and characterized using gas chromatography-mass spectrometry. To evaluate the antifungal effects and the modulating activity of Fluconazole (FCZ), the essential oil was diluted in DMSO (1 mL) and SDB medium (9 mL) and tested on 3 Candida strains using the serial microdilution method. In addition, a morphological transition assay was used to evaluate its capacity to inhibit fungal virulence.

Results: The major constituent of EOAU was the monoterpene β-myrcene (71.07%). The results indicate that the essential oil exhibits an antifungal effect, with C. tropicalis being the most susceptible species. At subinhibitory concentrations (MC/8), the EOAU enhanced the action of fluconazole against C. krusei and C. tropicalis. The EOAU strongly inhibited the morphological transition in C. tropicalis.

Conclusion: EOAU is rich in β-myrcene and exhibits an interesting fungistatic effect, making it a great natural candidate for inhibiting Candida spp. virulence.