20(R)-Ginsenoside-Rh19, a novel ginsenoside from alkaline hydrolysates of total saponins in stems-leaves of Panax ginseng / 中草药

ABSTRACT

Objective: To study the chemical constituents of alkaline hydrolysates of total saponins from the stems and leaves of Panax ginseng. Methods: The chemical constituents were isolated and purified by various chromatographic methods, and the chemical structures were identified by NMR and MS spectra analyses. Results: A total of 30 compounds were isolated and identified. Among them, 28 were determined as 20(S)-protopanaxadiol (1), 20(R)-protopanaxadiol (2), dammar-20(21),24-diene-3β,6α,12β-triol (3), dammar-20(22)E,24-diene-3β,6α,12β-triol (4), 20(S)-protopanaxatriol (5), 20(R)-protopanaxatriol (6), 20(S)-ginsenoside Rh2 (7), 20(R)-ginsenoside Rh2 (8), ginsenoside Rh16 (9), isoginsenoside Rh3 (10), 20(S)-dammar-3β,6α,12β,20,25-pentol (11), 20(R)-dammar-3β,6α,12β,20,25-pentol (12), ginsenoside Rk3 (13), 20(S)-ginsenoside Rh1 (14), 20(R)-ginsenoside Rh1 (15), ginsenoside F1 (16), ginsenoside Rh19 (17), 20(R)-ginsenoside Rh19 (18), dammar-20(22)E-ene-3β,6α,12β,25-tetrol (19), notoginsenoside T2 (20), ginsenoside Rg6 (21), 20(22)E-ginsenoside F4 (22), ginsenoside Rk1 (23), 20(S)-ginsenoside Rg3 (24), 20(R)-ginsenoside Rg3 (25), 20(S)-ginsenoside Rg2 (26), 20(R)-ginsenoside Rg2 (27), and 3β,6α,12β,25-tetrahydroxy-dammar-20(22)E-ene-6-O-α-L-rhamno- pyranosyl-(1→2)-β-D-glucopyranoside (28). Conclusion: Compound 18 is a new saponin. Compounds 3, 4, 11, 12, and 19 are rare dammarane-type triterpenes, and 7-10, 13-18, and 20-28 are rare ginsenosides.