Separation of Baicalein from Baicalin by Means of Solvent Extraction

Abstract

In this work, solvent extraction behaviors of some commercial extractants such as tri-n-octylphosphine oxide (TOPO), Cyanex 923 and Cyanex 925 for baicalein and baicalin decocted from Suctellaria root, which is a crude drug, were examined to elucidate their mutual separation by solvent extraction. Baicalein was extracted selectively by trialkylphosphine oxides over baicalin. From analyses of the extraction mechanism, the equilibrium constant of extraction reaction and enthalpy change were evaluated. A porous resin impregnated with Cyanex 923 in XAD-7 was prepared to remove baicalein from baicalin by using a column packed with the resin. Baicalein was able to be completely removed by this column operation.