Studies on Absorption, Distribution, Excretion and Metabolism of Ginseng Saponins. V. : The Decomposition Products of Ginsenoside Rb₂ in the Large Intestine of Rats

抄録

The decomposition of ginsenoside Rb₂ (Rb₂) in the rat large intestine after oral administration was investigated in detail. A part of Rb₂ was decomposed and six decomposition products (I-VI) were observed on thin-layer chromatogram. Among them, five products (I-V) were isolated, and identification of these compounds was done by carbon-13 nuclear magnetic resonance (¹³C-NMR).On the basis of ¹³C-NMR analysis, these compounds were identified as ginsenoside Rd (I), 3-O-β-D-glucopyranosyl-20-O-[α-L-arabinopyranosyl(1→6)-β-D-glucopyranosyl]-20(S)-proto-panaxadiol (II), ginsenoside F₂ (III), 20-O-[α-L-arabinopyranosyl(1→6)-β-D-glucopyranosyl]-20(S)-protopanaxadiol (IV), and compound K (V), respectively.