One-step separation of three flavonoids from Poacynum hendersonii by high-speed counter-current chromatography.

INTRODUCTION

Owing to them having the same traditional name, the leaves of Apoacynum venetum and Poacynum hendersonii are used indiscriminately in some areas of China. Although a series of studies have been conducted on Apoacynum venetum, there are only a few studies on Poacynum hendersonii.

OBJECTIVE

To develop an efficient method for the preparative isolation and purification of flavonoids from the leaves of Poacynum hendersonii by high-speed counter-current chromatography (HSCCC).

METHODOLOGY

Powdered Poacynum hendersonii lead was extracted three times with 75% ethanol at 60 °C for 3 h. The distribution constant (K(D) ) was measured to select an optimal two-phase solvent system for HSCCC separation. The purities of the target compounds were tested using HPLC and their structures were identified by ¹H-NMR and ¹³C-NMR.

RESULTS

Using a two-phase solvent system composed of n-butanol-petroleum ether-0.5% acetic acid (5:3:5, v/v), three main flavonoids, i.e. isoquercitrin, quercetin-3-O-sophoroside and quercetin-3-O-(6''-O-malonyl)-β-D-glucoside, were separated from 240 mg crude sample in a one-step separation by using HSCCC method. After further purification with a Sepdex-LH20 column, 5.7 mg isoquercitrin (LC purity 98.72%), 4.9 mg quercetin-3-O-sophoroside (LC purity 99.06%) and 7.4 mg quercetin-3-O-(6''-O-malonyl)-β-D-glucoside (LC purity 99.31%) were obtained, respectively.

CONCLUSION

The optimised high-speed counter-current chromatography method is fast, simple and efficient for the preparative separation of flavonoids from the leave of Poacynum hendersonii.