Degradation of Ginseng Saponins under Mild Acidic Conditions

Abstract

Ginseng saponins, ginsenosides Rg₁, Re and Rb₁, decomposed under mild acidic conditions to yield prosapogenins. The structures of the prosapogenins were investigated by ¹³C-NMR spectroscopy and Rg₁-prosapogenin II was shown to be a mixture of ginsenoside Rh₁, and its C-20 epimer, produced by hydrolysis followed by epimerization at C-20. Rg₁-prosapogenin III, the other prosapogenin derived from ginsenoside Rg₁; was a C-25,26 hydrated derivative of Rg₁-prosapogenin II. Re-prosapogenin II was identified as a mixture of ginsenoside Rg₂ and its C-20 epimer, and Re-prosapogenine III as a C-25,26 hydrated derivative of Re-prosapogenin II.

Key Word Index

Panax ginseng - Araliaceae - Saponin - Ginsenoside - Prosapogenin