Abstract
The first preparative separation of a flavonoid sulphate isorhamnetin 3‐sulphate from Flaveria bidentis (L.) Kuntze by counter‐current chromatography (CCC) was presented. Two kinds of solvent systems were used. A conventional organic/aqueous solvent system n‐butanol–ethyl acetate–water (4:1:5, v/v) was used, yielding isorhamnetin 3‐sulphate 2.0 mg with a purity of 93.4% from 83 mg of pre‐enriched crude extract obtained from 553 mg ethanol extract by macroporous resin. A one‐component organic/salt‐containing system composed of n‐butanol–0.25% sodium chloride aqueous solution (1:1, v/v) was also used, and the LC column packed with macroporous resin has been employed for desalination of the target compound purified from CCC. As a result, 2.1 mg of isorhamnetin 3‐sulphate with a purity of over 97% has been isolated from 402 mg of crude extract without pre‐enrichment. Compared with the conventional organic/aqueous system, the one‐component organic/salt‐containing aqueous system was more suitable for the separation of isorhamnetin 3‐sulphate, and purer target compound was obtained from the crude extract without pre‐enrichment using the new solvent system. The chemical structure was confirmed by ESI‐MS and ^1^H, ^13^C NMR. In summary, our results indicated that CCC using one‐component organic/salt‐containing aqueous solution is very promising and powerful for high‐throughput purification of isorhamnetin 3‐sulphate from Flaveria bidentis (L.) Kuntze.