A tractable method for the preparation of the ginsenoside compounds O and Mc1

Rare ginsenosides, compounds O and Mc1, were produced from the major ginsenosides Rb-2 and Rc by beta-glucosidase from Esteya vermicola via the pathways of Rb-2-compound O and Rc-compound Mc1. The biotransformation conditions for the compounds using Esteya vermicola CBS 115803 were established with a transformation temperature and time of 26 degrees C and seven days, respectively, and a pH value of 5.5 at 130 rpm. The structure of the key metabolite was confirmed by MS analysis. The biotransformation yields for the two compounds were 96.7 and 95.2%, respectively. A feasible method to recover the products was also developed, in which the products were purified from the fermentation broth, and the unreacted substrates were recovered from the mycelia. The present study provides a practical and potentially valuable approach that can be applied in the preparation of compounds O and Mc1 without byproducts.