LAUSR

This study presents an efficient strategy based on liquid-liquid extraction and pH-zone-refining counter-current chromatography for selective enrichment, separation and purification of alkaloid and organic acid from natural products. Firstly, an acid or base modified two-phase solvent system with max or min partition coefficient was developed for the liquid-liquid extraction of the crude extract. As a result, alkaloid or organic acid could be selectively enriched in upper or lower phase. Then pH-zone-refining counter-current chromatography was employed to separate and purify the selectively enriched alkaloid or organic acid efficiently. The selective enrichment and separation of five bufadienolide from toad venom of Bufo marinus was used as an example to show the advantage of this strategy. As a result, 759 mg of selectively enriched bufadienolide was obtained from 2 g of crude extract and the total content of five targets was increased from 14.64% to 83%. 31 mg of marinobufagin-3-adipoyl-L-arginine, 42 mg of telocinobufagin-3-pimeloyl-L-arginine, 51 mg of telocinobufagin-3-suberoyl-L-arginine, 132 mg of marinobufagin-3- suberoyl-L-arginine and 57 mg of bufalin-3-suberoyl-L-arginine were all simultaneously separated from 500 mg of selectively enriched sample, with the purity of 92.4%, 97.5%, 90.3%, 92.1% and 92.8%, respectively. This article is protected by copyright. All rights reserved.