Method: Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) were determined by microdilution technique, using Sabouraud Dextrose (SD) doubly concentrated and 96-well microplates. It was also verified the possible activity of eugenol on fungal cell wall. In addition, controls of strain viability and culture medium sterility were made. Nystatin was used as positive control and tests were performed in triplicate. The reading to determine MIC was done by visual method, which took into account the formation or non-formation of cellular clusters in the bottom of the wells. TCT (2,3,5 triphenyl tetrazolium chloride) was used in order to confirm presence of viable microorganisms in the non-inhibitory concentrations. Such dye reflects the action of dehydrogenase enzymes, involved in the process of cellular respiration.
Result: Eugenol showed MIC and MFC of 1,250 µg/mL. The outcomes suggest that eugenol does not act on fungal cell wall, since sorbitol test indicated MIC of 1,250 µg/mL. Nystatin presented MIC and MFC of 6,25 µg/mL.
Conclusion: Eugenol was proven to present antifungal activity on C. albicans, and its mechanism of action, probably, is not related to fungal cell wall.