Enrichment and isolation of barbigerone from Millettia pachycarpa Benth. using high-speed counter-current chromatography and preparative HPLC.

Enrichment of the anti-tumor compound barbigerone along with a rotenoid derivative from Millettia pachycarpa Benth. was performed by a two-step high-speed counter-current chromatography (HSCCC) separation process. In the first step, 155.8 mg of target fraction (Fra6) was obtained from 400 mg ethyl acetate extract of M. pachycarpa Benth. with an increase in barbigerone from 5.1 to 13% via HSCCC using a solvent system of n-hexane-ethyl acetate-methanol-water (5:4:5:3, v/v) under normal phase head to tail elution. HSCCC was repeated to eliminate the major contaminant in this initial fraction 6. After a separation time of 65 min, 22.1 mg barbigerone of 87.7% purity was obtained from Fra6 with the ternary solvent system of n-hexane-methanol-water (2:2:1, v/v) under normal phase elution. Finally, preparative HPLC was employed for the further isolation of barbigerone and the rotenoid derivative. The structures were confirmed by ESI-MS, (1)H NMR and (13)C NMR.