Preparative and rapid purification of saponins from Asparagus racemosus root by high performance centrifugal partition chromatography

Abstract

High performance centrifugal partition chromatography (HPCPC) was applied to the rapid isolation and purification of saponin glycosides in Asparagus racemosus Willd. root. A two-phase solvent system composed of CHCl3-MeOH-water (4:4:2, v/v) in descending mode was used for the separation, yielding shatavarin IX (1) and asparacoside (2) in one step. Asparanin A (3) and shatavarin V (4) were separated by repeated HPCPC fractionation using CH2Cl2- MeOH-water (4:4:2, v/v) as the solvent system, followed by either gel-filtration or TLC. Their structures were identified by NMR spectroscopy and ESI/MS. The A. racemosus extracts and 1, 2, 3 and 4 were cytotoxic towards human hepato- and prostate-carcinoma cell lines (IC50 14-37 μM), while primary human fibroblasts were less vulnerable (IC50 22-66 μM), i.e., every saponin glycoside showed selectivity towards carcinoma cells compared with normal fibroblasts. HPCPC has proven rapidity to separate complex mixtures of phytochemicals yielding quantities suited to biological studies.