Enhancement of the isolation selectivity of isoflavonoid puerarin using oligo-β-cyclodextrin coupled polystyrene-based media

The isolation selectivity of the isoflavonoid puerarin, a well-known traditional Chinese medicine, was studied when native and oligo-β-cyclodextrin (CDP) coupled polystyrene-based macroporous resins were used as adsorbents by static tests. The research results indicated that the CDP coupled resin HPD-100-CDP offered the best adsorption and desorption capacity for puerarin than others and its equilibrium adsorption data at 25 °C fit best to the Freundlich isotherm. The performance of separation of puerarin on HPD-100-CDP column in one step was evaluated. Based on the above experimental data, a novel medium PS-CDP was synthesized and its chromatographic retention behaviors were also explored. ESI-MS/MS, ¹H NMR spectroscopy and UV absorption spectrum were used for the detection and characterization of puerarin in isolated fraction. Under the optimum mobile phase, methanol/acetic acid/water = 5.0/6.6/88.4 (v/v/v), the purity and recovery of puerarin were 95.3% and 86.7%, respectively, by HPLC analysis. In conclusion, the PS-CDP medium can enhance the isolated selectivity of puerarin and it can be applied in preparative scale operations.