Preparative isolation of four ginsenosides from Korean red ginseng (steam-treated Panax ginseng C. A. Meyer), by high-speed counter-current chromatography coupled with evaporative light scattering detection

Ginseng (Panax ginseng C. A. Meyer) has been well known to have a variety of ginsenosides that show diverse biological activities. Especially, the components of ginsenosides are quite different depending on the processing method. Recently, there have been several reports showing that less polar ginsenosides from Korean red ginseng (steam-treated Panax ginseng) have potent biological activities such as radical scavenging, vasodilating and anti-tumor activities. In this study, we have isolated four known ginsenosides Rg3, Rk1, Rg5 and F4 from Korean red ginseng by high-speed counter-current chromatography (HSCCC) coupled with evaporative light scattering detection (ELSD). The enriched saponin fraction (350 mg) was separated by using methylene chloride–methanol–water–isopropanol (6:6:4:1, v/v) as the two-phase solvent system and yielded 28.6 mg of Rg5, 26.6 mg of Rk1, 32.2 mg of Rg3 and 8.1 mg of F4. The purity of these ginsenosides was assessed by HPLC–ELSD to be over 95%, and their structures were characterized by electrospray ionization mass spectrometry (ESI-MS), 1H NMR and 13C NMR.