Preparative isolation and purification of two flavonoid glycosides from Taraxacum mongolicum by high-speed counter-current chromatography

Two flavonoid glycosides, alquds and hesperidin were isolated and purified from the aerial part of Taraxacum mongolicum, a traditional Chinese medicine (TCM) by high-speed counter-current chromatography (HSCCC). After C18 open column chromatography served as enrichment step, high-speed counter-current chromatography (HSCCC) was used for the final purification. The target compounds were finally isolated and purified with a solvent system composed of n-hexane–n-butanol–water (1:1:2, v/v/v). In a single operation, 0.6 g of the enriched extracts of T. mongolicum was separated to yield 84.6 mg of alquds and 45.1 mg of hesperidin with the purity of 98.8% and 98.1%, respectively. The HSCCC fractions were analyzed by high-performance liquid chromatography (HPLC) and the chemical structures of the two flavonoid glycosides were identified by UV, ESI-MS, 1H NMR, 13C NMR and HMBC analysis. Alquds and hesperidin were obtained from the plant of genus Taraxacum for the first time, which may be used for in vitro and in vivo studies and reference substances for analytical purpose. This technique should also be applicable to the preparation of unknown bioactive compounds from traditional Chinese medicine (TCM).