Anti-adherent activity of Rosmarinus officinalis essential oil on Candida albicans: an SEM analysis

Abstract

Purpose: To evaluate the anti-adherent activity of Rosmarinus officinalis (Rosemary) essential oil on Candida albicans (ATCC289065). Methods: The effect of the essential oil of R. officinalis at concentrations of 0.56 mg/mL, 1.12 mg/mL and 2.25 mg/mL on C. albicans adherence was examined using Scanning Electron Microscopy (SEM) analysis. A test piece of acrylic resin, 2 mL of Sabouraud Dextrose broth, 0.2 mL of fungal inoculum and 2 mL of R. officinalis essential oil in the various test concentrations were combined in sterile glass tubes. Sterile distilled water and nystatin (100.000 IU/mL) were used as controls. The essential oil test products were combined with the fungal samples under two different conditions: at the same time as the other components of the adhesion device (t=0 h) or 24 h after the combination of the other components (t=24 h). The tubes were incubated at 37 °C for 48 h. The specimens were fixed and prepared for SEM analysis. Results: At 0.56 mg/mL, the effect of R. officinalis essential oil was similar to that of nystatin (t=0h and t=24 h). At 2.25 mg/mL, the essential oil caused significant cell disruption and inhibition of adhesion. An intermediate effect was observed at 1.12 mg/mL. Greater inhibition of adhesion was observed at t=24 h. Conclusion: The essential oil of R. officinalis had an anti-adherent effect on C. albicans. Greater inhibition of adhesion was observed in cultures undergoing cellular aggregation (t=24 h) and at higher concentrations of the natural product.