Phytochemical prospecting was performed by HPLC-DAD. The Inhibitory Concentration of 50% of mortality the microorganisms (IC50) was determined and a cell viability curve was obtained. Minimum Fungicidal Concentration (MFC) was determined by subculture in Sabourad Dextrose Agar. The effect of the combination extract/fluconazole was verified by microdilution, with the extracts in subinhibitory concentrations (MFC/16). Caffeic acid was the major compound of both extracts, representing 6.08% in the aqueous extract and 7.62% in the ethanolic extract. The extracts showed a fungistatic effect (MFC ≥ 16,384 μg/mL). The IC50 results demonstrated that the combination of the extracts with fluconazole were more significant than the products tested alone, with values from 4.9 to 34.8 μg/mL for the ethanolic extract/fluconazole and 5 to 84.7 μg/mL for the aqueous extract/fluconazole. The potentiating effect of fluconazole action was observed against C. albicans and C. tropicalis. In C. krusei the aqueous extract had an antagonistic effect.
Keywords: Fluconazole; Fungistatic effect; Medicinal plants; Phenolic compounds; Synergism.
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