Scanning electron microscopy ofCandida albicansATCC 10231 biofilms formed in the presence of fraction F2 or subfraction F2.4 fromStryphnodendron adstringens. Biofilms were treated with antifungal agents concentrations 64 fold higher than the minimum inhibitory concentration (MIC) values determined for the treatment of planktonic cells for 24-h incubations at 35°C. Compared to untreated controls (A-C), biofilms formed in the presence of 32 μg/mL amphotericin B (D-F) displayed a reduction in fungal biomass, with filamentation inhibition and the presence of irregular buds (arrows in F). Treatment with 1,000 μg/mL of fraction F2 (G-I) or subfraction F2.4 (J-L) led to the formation of biofilms with blastoconidia cells of altered shape, including ‘dumbell’ cells (I and L, arrows) and those with elongated bud necks (L, arrowhead). Scale bars: 1 mm (A, D, G and J), 20 μm (B, E, H and K) and 10 μm (C, F, I and L).