One-step preparation of molecularly imprinted hollow beads for pseudohypericin separation from Hypericum perforatum L. extracts

Abstract In the attempt to separate pseudohypericin (PH) from Hypericum Perforatum L. (or Saint John’s Wort, SJW) phyto-extracts, molecularly imprinted polymers (MIPs) hollow beads were prepared by one-step suspension polymerisation procedures and reported herein for the first time. The main reason for preparing such hollow materials refers to enhancing the accessibility of pH to the recognition sites that further leads to selective and high rebinding yields. In this respect, various terpolymer matrixes based on methacrylic acid (MAA), acrylonitrile (AN) and ethylene glycol dimethacrylate (EDMA) were tested for the ability to form micron-sized hollow beads. Morpho-structural analyses of resulted MIP beads confirmed their hollow structure. Evaluating the influence of different parameters like solvent, pH and concentration of the feed SJW extract, upon recognition and re-binding ability of MIPs for various naphtodianthrones (NTs) from SJW phyto-extracts, reflected that the optimum rebinding concentration, specificity and selectivity for PH can be atributed to the MIP systems with 50:50 and 100:0 (wt./wt.) of MAA:AN.