High-Speed Counter-Current Chromatography with an Online Storage Technique for the Preparative Isolation and Purification of Dihydroflavonoids from Sophora alopecuroides L.

INTRODUCTION: High-speed counter-current chromatography (HSCCC) is an efficient and non-absorption separation technique, but limitations still exist in simultaneous isolation of complex structures of natural products. Moreover, particular methods are various for different kinds of natural products.

OBJECTIVE: A novel HSCCC strategy combined with an online storage recycling elution (OSR-CCC) technique was developed for the quick separation of naturally occurring dihydroflavonoids from the extract of the herb Sophora alopecuroides L.

METHODOLOGY: In the separation procedure, a storage loop and two six-port valves were connected to a HSCCC system. Effluent A was subjected to an online storage loop and then to recycling separation three times after effluent B was collected in head-to-tail mode. After completion of the recycling separation of effluent A, the elution was switched to tail-to-head mode to collect effluent C. A biphasic solvent system of n-hexane/ethyl acetate/methanol/water (9:6:6:8, v/v/v/v) was used as the separation solvent during the whole elution.

RESULTS: Six constituents were isolated simultaneously from the extract (200 mg) of S. alopecuroides by running HSCCC non-stop, and their purities were higher than 95.0%. Their structures were determined as the pterocarpan glycoside sophoratonkin (1) (10.0 mg) and five dihydroflavonoids, alopecurone F (2) (5.4 mg), lehmannin (3) (11.0 mg), alopecurone A (4) (35.0 mg), sophoraflavanone G (5) (21.0 mg), alopecurone B (6) (31.0 mg).

CONCLUSION: This recycling HSCCC method combined with an online storage technique could be a rapid, effective and simple approach to isolate stilbene-dihydroflavonoids from herbs of the Sophora genus simultaneously. Copyright © 2017 John Wiley & Sons, Ltd.