Studies on the Saponins of Ginseng. IV. On the Structure and Enzymatic Hydrolysis of Ginsenoside-Ra1

Abstract

The presence of ginsenoside-Ra in Ginseng Radix has been demonstrated by thin-layer chromatography. Recently, ginsenoside-Ra was shown to be a mixture of more than two saponins. Among them, ginsenoside-Ra1 was isolated and its structure was determined on the basis of spectral, chemical and enzymatic hydrolysis evidence as 20(S)-protopanaxadiol 3-O-β-d-glucopyranosyl(1→2)-β-d-glucopyranosido-20-O-β-d-xylopyranosyl(1→4)-α-l-arabinopyranosyl(1→6)-β-d-glucopyranoside (1). Besides compound K (8), three prosapogenins, 20(S)-protopanaxadiol 3-O-α-d-glucopyranosido-20-O-β-d-glucopyranoside (7), 20(S)-protopanaxadiol 3-O-β-d-glucopyranosido-20-O-β-d-xylopyranosyl(1 → 4)-α-l-arabinopyranosyl(1→6)-β-d-glucopyranoside (9), and 20(S)-protopanaxadiol 20-O-β-d-xylopyranosyl(1→4)-α-l-arabinopyranosyl(1→6)-β-d-glucopyranoside (10) were obtained in the course of enzymatic hydrolysis of ginsenoside-Ra1. Further, 20(S)-protopanaxadiol 3-O-β-d-glucopyranosido-20-O-α-l-arabinopyranosyl (1→6)-β-d-glucopyranoside (5), 20(S)-protopanaxadiol 20-O-α-l-arabinopyranosyl(1→6)-β-d-glucopyranoside (6), 7 and 8 were obtained by enzymatic hydrolysis of ginsenoside-Rb2 (4). The course of enzymatic hydrolysis of ginsenosides with naringinase is also discussed. © 1982, The Pharmaceutical Society of Japan. All rights reserved.