Separation of isorhamnetin 3-sulphate and astragalin from Flaveria bidentis (L.) Kuntze using macroporous resin and followed by high-speed countercurrent chromatography.

D4020 resin offered the best dynamic adsorption and desorption capacity for total flavonoids based on the research results from ten kinds of macroporous resin. A column packed with D4020 resin was used to optimize the separation of total flavonoids from Flaveria bidentis (L.) Kuntze extracts. The content of flavonoids in the product was increased from 4.3 to 30.1% with a recovery yield of 90%. After the treatment with gradient elution on D4020 resin, the contents of isorhamnetin 3-sulfate and astragalin were increased from 0.49 to 8.70% with a recovery yield of 74.1% and 1.16 to 30.8%, with a recovery yield of 92.2%, respectively. Further purification was carried out by one-run high-speed countercurrent chromatography yielding 4.5 mg of isorhamnetin 3-sulfate at a high purity of 96.48% and yielding 24.4 mg of astragalin at a high purity of over 98.46%.