Biotransformation of tetrahydrocarvone and biological effects

In this present study, the monoterpene tetrahydrocarvone (carvomenthone, C10H180) used as flavoring agent, was subjected to microbial biotransformation experiments, to the best of our knowledge for the first time, by using 20 different bacteria, yeast, and fungi, respectively. Six mono- and dihydroxylated derivatives of tetrahidrocarvone were identified by gas chromatography-mass spectroscopy (GC-MS) after the biotransformation studies. Scale up experiments using Bacillus velezensis NRRL B-14580 resulted in the isolation and charachterization of three metabolites p-menthane-1,2-diol and p-menthane-2-ol?s two enantiomers. Furthermore, the purified metabolites were subjected to in vitro antibacterial, anticandidal, anti-oxidant evaluations and bioauthographic pancreatic lipase inhibition assays. The bioassay results indicated that (1R,2R,5R)-p-menthane-2-ol was effective for the inhibitors of anticandidal activity against C.glabrata. Additionally, pancreatic lipase activity was inhibited more stronger by 1R-2R-p-menthane-2-ol than other metabolites, tetrahydrocarvone and standard orlistat