Preparative separation and purification of bufadienolides from Chinese traditional medicine of ChanSu using high-speed counter-current chromatography.

A preparative high-speed counter-current chromatography method for isolation and purification of bufadienolides from ChanSu was developed by using a stepwise elution with two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water at the ratios of 4:6:2:4 v/v, 4:6:2.5:4 v/v and 4:6:3.2:4 v/v. A total of 3.8 mg of gamabufotalin (1), 7.2 mg of arenobufagin (2), 3.4 mg of telocinobufagin (3), 5.3 mg of bufotalin (4), 8.5 mg of cinobufotalin (5) and 8 mg of bufalin (6) were obtained in one-step separation from 80 mg of the crude extract with purity of 92.7, 96.7, 87.2, 97.3, 94.9 and 99.4%, respectively. Their chemical structures were identified on the basis of (1)H-NMR and (13)C-NMR technology.