Antifungal Activity of a Hydroethanolic Extract From Astronium urundeuva Leaves Against Candida albicans and Candida glabrata

We have previously reported on the activity of different extracts from sp. against , with the hydroethanolic extract prepared from leaves of , an arboreal species widely distributed in arid environments of South America and often used in folk medicine, displaying the highest activity. Here we have further evaluated the antifungal activity of this extract against strains of and , the two most common etiological agents of candidiasis. The extract was tested alone and loaded into a nanostructured lipid system (10% oil phase, 10% surfactant and 80% aqueous phase, 0.5% Poloxamer 407 ). susceptibility assays demonstrated the antifungal activity of the free extract and the microemulsion against both species, with increased activity against , including collection strains and clinical isolates displaying different levels of resistance against the most common clinically used antifungal drugs. Checkerboard results showed synergism when the free extract was combined with amphotericin B against . Serial passage experiments confirmed development of resistance to fluconazole but not to the free extract upon prolonged exposure. Although preformed biofilms were intrinsically resistant to treatment with the extract, it was able to inhibit biofilm formation by at concentrations comparable to those inhibiting planktonic growth. Cytotoxicity assays in different cell lines as well as an alternative model using L. confirmed a good safety profile of the both free and loaded extracts, and an assay demonstrated the efficacy of the free and loaded extracts when used topically in a rat model of vaginal candidiasis. Overall, these results reveal the promise of the leaves extract to be further investigated and developed as an antifungal.