Preparative separation of four major bufadienolides from the Chinese traditional medicine, Chansu, using high-speed counter-current chromatography.

A preparative, high-speed, counter-current chromatographic (HSCCC) method for the isolation and purification of bufadienolides from Chansu was successfully developed by using stepwise elution with a two-phase solvent system composed of n-hexane: chloroform: methanol: water (4:1:2.5:5 and 4:1:4:5, v/v). A total of 7.5 mg of cinobufotalin (1), 8.0 mg of bufalin (2), 14.0 mg of cinobufagin (3) and 9.5 mg of resibufogenin (4) were obtained in a one-step separation from 80 mg of the crude extract with purities of 93.2%, 98.7%, 99.2%, and 99.4%, respectively. The chemical structures were determined from 1H NMR and 13C NMR spectroscopic data.