Abstract: Three flavones were isolated and purified from Nelumbo nucifera Gaertn. by the combination of silica gel chromatography and high-speed counter-current chromatography (HSCCC). The crude extract of N. nucifera was separated by silica gel chromatography and the fraction containing flavones was obtained. Then, the fraction was separated by HSCCC with two phase solvent systems composed of ethyl acetate-ethanol-water-acetic acid (4:1:5:0.025, v/v/v/v). The upper phase was as the stationary phase and the lower phase as the mobile phase. Under the conditions of a flow rate of 2.0 mL/min, while the apparatus rotated at 800 r/min and the detection wavelength was at 254 nm, 6.1 mg of quercetin-3-O-β-D-glucuronide, 14.8 mg of myricetin-3-O-β-D-glucopyranoside and 20.2 mg of astragalin were obtained from 150 mg of the crude sample in one step. The purities determined by high performance liquid chromatography (HPLC) were 97.0%, 95.4% and 96.3%, respectively. The structures of the target compounds were identified by electrospray ionisation mass spectrometry (ESI-MS),1H-nuclear magnetic resonance(1H-NMR) and 13C-nuclear magnetic resonance(13C-NMR). This method that has practical value not only saves solvent but also is convenient. It is effective in the separation of flavones from N. nucifera, and provides theoretical foundation for the further development and use of N. nucifera resources.

Key words: astragalin, high-speed counter-current chromatography (HSCCC), myricetin-3-O-β-D-glucopyranoside, Nelumbo nucifera Gaertn, quercetin-3-O-β-D-glucuronide, silica gel chromatography