Fungal biotransformation of cyclademol and antimicrobial activities of its metabolites

Abstract

Cyclademol (1) was converted for the first time to 1-(4-hydroxy-3,3-dimethylcyclohexyl) ethanone (2) and 4-(1-hydroxyethyl)-2,2-dimethylcyclohexanol (3) with 31.2 and 15.1% yields by Aspergillus Niger and Neurospora crassa, respectively. The resulting metabolite structures were established by FT-IR, MS and NMR spectroscopic studies, respectively. In addition, the in vitro antimicrobial activities of the substrates and metabolites were evaluated comparatively both by using agar dilution and microdilution methods. The minimum inhibitory concentrations (MIC) of the tested compounds against a panel of pathogenic bacterial strains ranged from 1000 - 4000 μg/mL, whereas the MIC values against fungal strains were between 500 -1000 μg/mL.