Preparative isolation of hydrolysable tannins chebulagic acid and chebulinic acid from Terminalia chebula by high-speed counter-current chromatography

As a chromatographic column, the high‐speed counter‐current chromatography system was equipped with a preparative HPLC series, enabling the successful isolation of hydrolysable tannins from the fruits of Terminalia chebula, a traditional Chinese medicine. The two‐phase solvent system was composed of n‐hexane‐ethyl acetate‐methanol‐water (1 : 20 : 1 : 20 v/v). As a result, 33.2 mg chebulagic and 15.8 mg chebulinic acids were obtained in one step from 300 mg of crude extract. Their purities were determined by HPLC to be 95.3 and 96.1%, respectively. The chemical structures were identified by their MS and 1H NMR spectra.