State-of-the-art separation of ginsenosides from Korean white and red ginseng by countercurrent chromatography

Abstract

Ginseng (Panax ginseng C. A. Meyer) has been one of the most popular herbs used for nutritional and medicinal purposes by the people of eastern Asia for thousands of years. Ginsenosides, the mostly widely studied chemical components of ginseng, are quite different depending on the processing method used. A number of studies demonstrate the countercurrent chromatography (CCC) separation of ginsenosides from several sources; however, there is no single report demonstrating a one-step separation of all of these ginsenosides from different sources. In the present study, we have successfully developed an efficient CCC separation methodology in which the flow-rate gradient technique was coupled with a new solvent gradient dilution strategy for the isolation of ginsenosides from Korean white (peeled off dried P. ginseng) and red ginseng (steam-treated P. ginseng). The crude samples were initially prepared by extraction with butanol and were further purified with CCC using solvent gradients composed of methylene chloride-methanol-isopropanol-water (different ratios, v/v). Gas chromatography coupled with flame ionization detector was used to analyze the components of the two-phase solvent mixture. Each phase solvent mixture was prepared without presaturation, which saves time and reduces the solvent consumption. Finally, 13 ginsenosides have been purified from red ginseng with the new technique, including Rg1, Re, Rf, Rg2, Rb1, Rb2, Rc, Rd, Rg3, Rk1, Rg5, Rg6, and F4. Meanwhile, eight ginsenosides have been purified from white ginseng, including Rg1, Re, Rf, Rh1, Rb1, Rb2, Rc, and Rd by using a single-solvent system. Thus, the present technique could be used for the purification of ginsenosides from all types' ginseng sources. To our knowledge, this is the first report involving the separation of ginsenoside Rg2 and Rg6 and the one-step separation of thirteen ginsenosides from red ginseng by CCC.