Chemical studies on crude drug processing. VI. Chemical structures of malonyl-ginsenosides Rb1, Rb2, Rc, and Rd isolated from the root of Panax ginseng C.A. Meyer.

Abstract

Four malonylated dammarane-type triterpene oligoglycosides, named malonyl-ginsenosides Rb1, Rb2, Rc, and Rd, were isolated from the water-soluble portion of the dried root of Panax ginseng C. A. MEYER (Araliaceae), together with previously known ginsenosides. On the basis of chemical and physicochemical evidence including metastable ion analysis of liquid secondary ion mass spectra, the structures of malonyl-ginsenosides Rb1, Rb2, Rc, and Rd have been elucidated as 3-O-[6-O-malonyl-β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl]-20-O-[β-D-glucopyranosyl(1→6)-β-D-glucopyranosyl]-20(S)-protopanaxadiol, 3-O-[6-O-malonyl-β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl]-20-O-[α-L-arabinopyranosyl(1→6)-β-D-glucopyranosyl]-20(S)-protopanaxadiol, 3-O-[6-O-malonyl-β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl]-20-O-[α-L-arabinofuranosyl(1→6)-β-D-glucopyranosyl]-20(S)-protopanaxadiol, and 3-O-[6-O-malonyl-β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl]-20-O-[β-D-glucopyranosyl]-20(S)-protopanaxadiol, respectively.