Preparative isolation and purification of coumarins from Peucedanum praeruptorum Dunn by high-speed counter-current chromatography

A preparative high-speed counter-current chromatography (HSCCC) method for isolation and purification of coumarins from Peucedanum praeruptorum Dunn (Baihuaqianhu in Chinese) was successfully established by using light petroleum–ethyl acetate–methanol–water as the two-phase solvent system in gradient elution mode. The upper phase of light petroleum–ethyl acetate–methanol–water (5:5:5:5, v/v) was used as the stationary phase of HSCCC. The mobile phase used in HSCCC was the lower phase of light petroleum–ethyl acetate–methanol–water (5:5:5:5, v/v) and light petroleum–ethyl acetate–methanol–water (5:5:6.5:3.5, v/v) that was changed in gradient. Four kinds of coumarins and another unknown compound were obtained and yielded 5.3 mg of qianhucoumarin D, 7.7 mg of Pd–Ib, 35.8 mg of (+)-praeruptorin A, 31.9 mg of (+)-praeruptorin B and 6.4 mg of unknown compound with the purity of 98.6%, 92.8%, 99.5%, 99.4% and 99.8% in one-step separation, respectively. The structures of the coumarins were identified by 1H NMR and 13C NMR.