Selective recognition and preliminary separation of hepatoprotective component silybin from milk thistle seeds by the prepared core–shell magnetic molecularly imprinted polymer

Abstract

Using hepatoprotective component silybin as the template, MAA as the functional monomer, EGDMA as the cross linker, acetonitrile as the solvent, and Fe3O4 as the magnetic substrate, the silybin magnetic molecularly imprinted polymer(S-MIP) was successfully prepared by the reverse atom transfer radical precipitation polymerization(RATRP), and non-ion imprinted polymer(NIP) was also synthesized by the same procedure only in the absence of silybin. On the basis of computer simulation and L9(34) orthogonal array design matrix, the optimal preparation conditions were finally obtained as follows that the molar ratio of silybin, MAA, and EGDMA was 1:5:60. The prepared materials were respectively characterized by SEM, XRD, FT-IR, VSM and TGA, and the kinetic analyses explored that the adsorption process of S-MIP was better describled by the pseudo-second order kinetic equation, meanwhile, scatchard analysis illustrated that the heterogeneous binding sites existed in S-MIP. Both the selectivity factor α (2.232) and the relative selectivity factor β (2.201) of S-MIP showed the aim material had the excellent specific recognition capacity and selection adsorption property to silybin. Additionally, the recycling reuse experiments explored S-MIP was of a good stability and could be used repeatedly at least five times with only 15.8% decrease of adsorption capacity when applied in the fifth experiment, and the evaluation experiments by HPLC for silybin extraction from the medicinal herb milk thistle seeds indicated that S-MIP had the potential application in separating the natural hepatoprotective component silybin from the herbal plants.