Red propolis hydroalcoholic extract inhibits the formation of Candida albicans biofilms on denture surface

To evaluate the antifungal activity of the red propolis hydroalcoholic extract (RPHE) against biofilms. The minimum inhibitory and fungicidal concentrations (MIC and MFC) of the RPHE were determined by the microdilution technique. biofilms were formed on the surface of resin specimens preconditioned with artificial saliva (1h). The specimens (N=48) were equally divided according to the four solutions used for anti-biofilm evaluation (n=12 per group). After overnight incubation, biofilms were daily exposed (2x/day for 15 min) along 3 days with 3% RPHE, 0.12% chlorhexidine (CHX), 50,000 IU/mL nystatin (NYS) or saline (0.9% NaCl). Biofilms were analyzed regarding the number of viable microorganisms (CFU/mL), the metabolic activity (MTT assay) and the proportion of hyphae (optical microscopy). The MIC and MFC of RPHE were respectively 0.29 mg/mL (0.03%) and 1.17 mg/mL (0.12%). There was no difference in the microorganisms' viability (CFU/mL) among groups treated with RPHE (4.92×103), CHX (3.33×102) or NYS (6.8×104), being all of them different from NaCl (3.93×107) (