Separation and purification of puerarin with solvent extraction

The partitioning behavior of puerarin from extract using n-butanol/water two-phase solvent system was investigated. The results showed that puerarin can be selectively separated from the hydrophilic impurities and the hydrophobic impurities by a double solvent extraction. It is advantageous to decrease the pH for the first solvent extraction of puerarin, whereas it may become favorable to increase the pH for the second solvent extraction. The partition coefficients of puerarin decrease as the initial concentration of puerarin increases.