A simple and efficient protocol for large-scale preparation of three flavonoids from the flower of Daphne genkwa by combination of macroporous resin and counter-current chromatography.

In this paper, macroporous resin column chromatography and counter-current chromatography (CCC) were applied for large-scale preparative separation of three flavonoids from the flower of Daphne genkwa, a famous Chinese medicinal herb. Nine kinds of resins were investigated by adsorption and desorption tests and D101 macroporous resin was selected for the first cleaning-up, in which 40% aqueous ethanol was used to remove the undesired constituents and 90% aqueous ethanol was used to elute the targets. The crude extract after the first step was directly subjected to the preparative CCC purification using the solvent system composed of n-hexane-ethyl acetate-methanol-water (4:5:4:5, v/v). The compounds apigemin (823 mg), 3-hydroxyl-genkwanin (842 mg) and genkwanin (998 mg) with the purities of 98.79, 97.71 and 93.53%, respectively, determined by HPLC were produced from 3-g crude extract only in one CCC run. Their chemical structures were identified by MS, UV and the standards.