Aims: The objective of this study was to investigate the effectiveness of (+)-β-pinene inhibition
on Candida spp. growth, aiming at elucidation of the mechanism of action; to determine fungal cell
enzyme binding activity (through molecular docking simulations) and its effects on biofilm reduction.
Methods: Candida strains (n=25) from referenced and clinical origins, either susceptible or resistant to
standard clinical antifungals, were tested for determination of Minimum Inhibitory Concentration
(MIC); Minimum Fungicidal Concentration (MFC); and microbial death curves upon treatment with
(+)-β-pinene; the effects of (+)-β-pinene on the cell wall (sorbitol assay), membrane ergosterol binding,
and effects on biofilm were evaluated by microdilution techniques. We also evaluated the interactions
between (+)-β-pinene and cell wall and membrane enzymes of interest.
Results: The MIC values of (+)-β-pinene ranged from <56.25 to 1800 µmol/L. The MIC of (+)-β-pinene
did not increase when ergosterol was added to the medium, however it did increase in the presence of
sorbitol, leading to a doubled MIC for C. tropicalis and C. krusei. The results of the molecular docking
simulations indicated better interaction with delta-14-sterol reductase (−51 kcal/mol). (+)-β-pinene presents
anti-biofilm activity against multiples species of Candida.
Conclusion: (+)-β-pinene has antifungal activity and most likely acts through interference with the cell
wall; through molecular interaction with Delta-14-sterol reductase and, to a lesser extent, with the 1,3-β-
glucan synthase. This molecule was also found to effectively reduce Candida biofilm adhesion.