Preparative isolation and purification of coumarins from Cnidium monnieri (L.) Cusson by high-speed counter-current chromatography.

A high-speed counter-current chromatography (HSCCC) method for separation and purification of coumarins from Cnidium monnieri (L.) Cusson was developed by using stepwise elution with a pair of two-phase solvent system composed of light petroleum-ethyl acetate-methanol-water at volume ratios of 5:5:5:5, 5:5:6:4 and 5:5:6.5:3.5. Five kinds of coumarins were obtained and yielded 7.6 mg of xanthotoxin(I), 7.6 mg of isopimpinellin(II), 9.7 mg of bergapten(III), 60.5 mg of imperatorin(IV), 50.6 mg of osthole(V) and 10.2 mg of one unknown compound from 150mg crude sample. The purity of these compounds was 95.0%, 99.6%, 99.7%, 100%, 100% and 98.1%, respectively, as determined by HPLC. Their structures were identified by 1H NMR.