Application of High-Speed Counter-Current Chromatography Preparative Separation of Flavone C-Glycosides From Lophatherum gracile

Abstract

Preparative high-speed counter-current chromatography (HSCCC) was used to separate and purify bioactive constituents from the stems and leaves of Lophatherum gracile Brongn. Six flavone C-glycosides each at over 95% purity including two new compounds were obtained in one-step separation by HSCCC with an optimized two-phase solvent system composed of ethyl acetate-n-butanol-ethanol-water at volume ratio of 4:2:1.5:8.5 (v/v/v/v). The experiment yielded 19.9 mg of luteolin 6-C-β-D-galactopyranosiduronic acid (1→2)-β-D-glucopyranoside (1), 28.5 mg of luteolin 6-C-α-L-arabinopyranosyl-7-O-β-D-glucopyranoside (2), 31.5 mg of isoorientin (3), 44.8 mg of orientin (4), 25.3 mg of swertiajaponin (5) and 12.1 mg of apigenin 6-C-β-D-galactopyranosiduronic acid (1→2)-β-D-glucopyranoside (6) from 500 mg of crude extracts. The purity of these compounds was determined by high-performance liquid chromatography (HPLC). Their chemical structures were identified by electron spray ionization mass spectroscopy (ESI-MS), ¹H and ¹³C nuclear magnetic resonance spectroscopy (NMR).

Keywords:

• flavone C-glycoside
• Gramineae
• High-speed counter-current chromatography
• Lophatherum gracile

ACKNOWLEDGEMENTS

This work was supported financially by the Program for Changjiang Scholars and Innovative Research Team in University (No. IRT0965), the National Natural Science Foundation of China (No. 81072535), the Natural Science Foundation of Guangdong Province (No. 8351063201000003), the Science and Technology Development Fund of Macao Special Administrative Region (No. 013/2008/A1), and the Science and Technology Planning Project of Guangzhou (No. 2010U1-E00531-6).