Separation of Saponins from the Roots of Platycodon grandiflorum by High-speed Counter- Chromatography and their Anticancer Activity

Platycosides, the primary saponins of the root of Platycodon grandiflorum (Platycodi Radix), are known to have diverse biological activities, exerting anti-inflammation, anti-allergy, anti-tumor, anti-obesity and anti-hyperlipidemia effects. The isolation of six bioactive platycosides (platycoside E, platycodin D3, platycodin D, and each deapiose structures) on a preparative scale, high-speed counter-current chromatography (HSCCC) was performed using a two-phase solvent system composed of hexane-n-butanol-water (1:40:20, v/v) and (1:10:5, v/v), in combination with effluent monitoring by evaporative light scattering detection. Minor saponins, acetylated isomers of the major saponin, were also isolated using a multi-step process including high-speed counter-current chromatography (HSCCC) and preparative reversed-phase high-performance liquid chromatography (HPLC). After the separation of the major components, the enriched minor saponin fraction was used for this study. A two-phase solvent system consisting of chloroform-methanol-isopropanol-water (3:2:2:3, v/v) was used for HSCCC. HSCCC fractions were further purified by preparative reversed-phase HPLC, yielding 3“-O-acetylplatycodin D, polygalacin D, 2“-O-acetylplatycodin D, 3“-O-acetylpolygalacin D, and 2“-O-acetylpolygalacin D. Especially, the anticancer activity of major and minor platycosides has been studied and the results will be presented.