Elution-extrusion Counter-current Chromatography Separation of Two New Benzyl Ester Glucosides and Three Other High-polarity Compounds from the Tubers of Pleione bulbocodioides

ABSTRACT Introduction The tubers of Pleione bulbocodioides (Franch.) Rolfe, with gastrodin and benzyl ester glucosides as main components, have been used in traditional Chinese medicine for the treatment of various cancers and bacterial infections. Up to now, their official quality control method is still inadequate, and the difficulty of obtaining these high‐polarity compounds is one of the major reasons. Objective To develop a rapid and efficient method for preparative separation of the high‐polarity compounds gastrodin and benzyl ester glucosides. Methods An optimised solvent system composed of n‐butanol:ethanol:water (20:1:20, v/v/v) was applied for the elution‐extrusion counter‐current chromatography (EECCC) separation. The upper phase was used as the stationary phase, and the lower phase was used as the mobile phase at a flow rate of 1.5 mL/min, a rotation speed of 850 rpm and a temperature of 35°C. Results Five high‐polarity glucosides, including two new compounds, (E)‐4‐β‐D‐glucopyranosyloxycinnamic acid 9‐(4‐β‐D‐glucopyranosyloxybenzyl) ester (4 mg) and (Z)‐2‐(2‐methylpropyl)butenedioic acid bis(4‐β‐D‐glucopyranosyloxybenzyl) ester (9 mg), and three main components, gastrodin (87 mg), dactylorhin A (60 mg) and militarine (15 mg), with HPLC purities of 95.4%, 96.4%, 91.1%, 97.2% and 95.5% respectively, were yielded from 400 mg of the prepared sample. Conclusion Elution‐extrusion counter‐current chromatography could be used as a useful tool for the separation of high‐polarity compounds such as gastrodin and benzyl ester glucosides and the enrichment of the minor ones. Copyright © 2013 John Wiley & Sons, Ltd. The tubers of Pleione bulbocodioides (Franch.) Rolfe, as a traditional Chinese medicine, have been used for the treatment of various cancers and bacterial infections. Elution‐extrusion counter‐current chromatography (EECCC), a support‐free counter‐current chromatography technique, showed its great advantage in separation of high‐polarity compounds. In this research, we successfully used EECCC as a useful tool for the separation of gastrodin and benzyl ester glucosides, including two new ones from this herbal medicine.