Enzymatic transformation of the major ginsenoside Rb1 to compound K by Weissella hellenica DC06

In the present study, the major ginsenoside Rb1 was transformed into the more pharmacologically active minor ginsenoside compound K (C-K) via the enzymatic activity of food grade Weissella hellenica DC06 isolated from kimchi, a traditional Korean fermented food. The transformation products were analyzed by TLC, HPLC, and LC/MS. Within 4 d of incubation, 100% of Rb1 was decomposed and converted into F2 and C-K. The crude enzyme of W. hellenica DC06 hydrolyzed the two glucose moieties attached to the C-3 position and the outer glucose moiety attached to the C-20 position of the ginsenoside Rb1. Strain DC06 hydrolyzed ginsenoside Rb1 along the following pathway: Rb1→Rd→F2→CK. The optimum temperature and pH of the enzyme activity was 37°C and 7.0, respectively. DC06 was identified as a W. hellenica species based on its 16S rRNA gene sequences through the construction of a phylogenetic tree and homology analysis. This is the first report of the bioconversion of ginsenoside Rb1 to ginsenoside C-K using W. hellenica DC06.