title: Degradation of ginseng saponins under mild acidic conditions.
abstract: Ginseng saponins, ginsenosides Rg (1), Re and Rb (1), decomposed under mild acidic conditions to yield prosapogenins. The structures of the prosapogenins were investigated by (13)C-NMR spectroscopy and Rg (1)-prosapogenin II was shown to be a mixture of ginsenoside Rh (1), and its C-20 epimer, produced by hydrolysis followed by epimerization at C-20. Rg (1)-prosapogenin III, the other prosapogenin derived from ginsenoside Rg (1); was a C-25,26 hydrated derivative of Rg (1)-prosapogenin II. Re-prosapogenin II was identified as a mixture of ginsenoside Rg (2) and its C-20 epimer, and Re-prosapogenine III as a C-25,26 hydrated derivative of Re-prosapogenin II.
authors.affiliation: Natural Product Research Institute, Seoul National University, Seoul, Korea.
authors.forename: B H
authors.initials: BH
authors.lastname: Han
authors.forename: M H
authors.initials: MH
authors.lastname: Park
authors.forename: Y N
authors.initials: YN
authors.lastname: Han
authors.forename: L K
authors.initials: LK
authors.lastname: Woo
authors.forename: U
authors.initials: U
authors.lastname: Sankawa
authors.forename: S
authors.initials: S
authors.lastname: Yahara
authors.forename: O
authors.initials: O
authors.lastname: Tanaka