Preparation of flavone di-C-glycoside isomers from Jian-Gu injection (Premna fulva Craib.) using recycling counter-current chromatography

Abstract Jian-Gu Injection (JGI, Premna fulva Craib) has been demonstrated to be effective in the clinical treatment of bone hyperplasia. However, an effective purification method of the JGI flavone C -glycosides as reference materials is not available. The present work developed a recycling counter-current chromatography approach to prepare these materials in high quality. An optimized biphasic solvent system composed of ethyl acetate/ n -butanol/water (1:9:10, v/v/v) was employed to purify the five congeneric flavone C -glycosides, identified as apigenin 6,8-di- C - β - d -glucopyranoside (vicenin 2), apigenin 6- C - β - d -xylopyranosyl-8- C - β - d -glucopyranoside (vicenin 1), apigenin 6- C - β - d -xylopyranosyl-8- C - β - d -galactopyranoside, apigenin 6- C - β - d -glucopyranosyl-8- C - β - d -xylopyranoside (vicenin 3), and apigenin 6- C - β - d -galactopyranosyl-8- C - β - d -xylopyranoside, by means of UHPLC-PDA-ESI-IT-ToF-MS n and NMR spectroscopy.