Resumo

Throughout the last twenty years, the yeasts most commonly isolated from systemic fungal infections have been species of Candida spp. Among invasive fungal infections, C. albicans has been reported in the literature as a major Candida species causing fungemia in patients with malignancies. The emergence of antimicrobial resistance and the limited efficacy of current antifungal agents have motivated the exploration of new drugs with relatively low toxicity that can reduce the chances of developing resistance. Natural products from plants have attracted scientific interest for their antifungal properties. Plants belongin to Mimosa genus are known to possess sedative, emetic, and tonic properties, and has been used traditionally in the treatment of various ailments including alopecia, diarrhea, dysentery, insomnia, tumor, and various urogenital infections. Recently, several reports have been demosntrated that Mimosa species possess antimicrobial properties. Herein, the synergistic effect of different protein fractions from seeds of Mimosa regnellii and fluconazole (FLC) was evaluated against FLC-resistant strains of C. albicans via broth microdilution susceptibility assay (CLSI document M27-A3). Over a period 24 h exposure at 35°C, none of tested fractions (0.125-64 μg/mL) showed antifungal activity (MIC50 > 64 μg/mL), but when combined with FLC (2 µg/mL) a specific fraction was able to significantly interfere on candida growth, as demonstrated by reduction of MIC values (0.125 µg/mL) and by fractional inhibitory concentration index (FICI ≤ 0.5). In conclusion, the preliminary data suggest that active protein fraction obtained from partitioning of the crude seeds extract of M. regnellii could be considered a potential source of antifungal proteins when combined with FLC against C. albicans resistant to this azolic compound.