Microbial deglycosylation and ketonization of ginsenoside by Cladosporium cladosporioide and their anticancer activity.

Ginseng has been used for thousands of years in Asian countries as a traditional medicinal herb and has gained great popularity in the past decade. Ginsenosides are the major pharmacological components in ginseng. We here show that Cladosporium cladosporioide is able to convert the major ginsenoside Rb1 into four known metabolites (ginsenosides Rd, F2, CK and PPD) and two new metabolites [12β-hydroxydammar-3-one-20(S)-O-β-D-glucopyranoside (3-oxo-CK) and dammar-24-en-12β,20(S)-diol-3-one (3-oxo-PPD)]. CK, PPD and 3-oxo-PPD were shown to have a potent antiproliferative activity against A549 lung cancer cells. We found that Rb1 → Rd → F2 → CK → PPD or 3-oxo-CK → 3-oxo-PPD represents the ginsenoside metabolic pathway.