Summary

Ginsenoside-Rk₃ and Ginsenoside-Rh₄ Isolated

from Processed Vietnamese Ginseng

Vietnamese ginseng (Panax vietnamensis Ha et Grushv.), a Panax species growing in high mountains in the middle of Vietnam. The unprocessed underground part of this species has been used with the same therapeutic indications as those of   Panax ginseng. In our previous study [4], remarkable changes in the saponin composition of steamed Vietnamese ginseng was detected  by TLC and HPLC  in comparison with that of fresh Vietnamese ginseng. This continuing work was aimed to isolate and demonstrate newly formed saponins in Vietnamese ginseng after the steaming process. Two among three dammarane-type triterpenoid saponins were isolated and elucidated as ginsenoside-Rk₃ and ginsenoside-Rh₄ by using spectroscopic analyses including MS and NMR. Ginsenoside-Rh₄ was previously isolated in Vietnamese ginseng at very low yield (ca. 0.0145% as compared with the total saponin) [2]. However, it was isolated in much higher yield (0.13%) in this study. In addition, for the first time, ginsenoside-Rk₃ was found in steamed Vietnamese ginseng.

Keywords: Steamed Vietnamese ginseng, Panax vietnamensis, ginsenoside-Rk₃, ginsenoside-Rh_4.