Magnetic Molecularly Imprinted Polymer Combined with Solid-Phase Extraction for Purification of Schisandra chinensis Lignans

Molecularly imprinted polymers (MIPs) can specifically recognize template molecules in solution with imprinted cavities. Due to their capacity for scalable production, they can be used to isolate target products from natural products for industrial production in the fields of pharmaceuticals and food. In this study, magnetic single-template molecularly imprinted polymers (St-MIPs) instead of magnetic multi-template molecularly imprinted polymers (Mt-MIPs) were prepared by surface imprinting using Schizandrol A as a template molecule and deep eutectic solvent (DES) as a functional monomer, combined with solid-phase extraction (SPE) for the adsorption and separation of Schizandrol A, Schisantherin A, Schizandrin A, and Schizandrin B from <i>Schisandra chinensis</i> (Turcz.) Baill. (<i>S. chinensis</i>) fruits extracts. The synthesized MIPs were characterized by FT-IR, TEM, SEM, TG, XRD and VSM, and their adsorption properties were also evaluated. MIPs can specifically recognize the template molecules with high reusability. The purity of the total <i>S. chinensis</i> lignans after SPE was 74.05%, among which that of Schizandrol A, Schisantherin A, Schizandrin A, and Schizandrin B was 33.38%, 8.69%, 16.33% and 15.67%, respectively. Moreover, the one-step synthesis of carrier was easy to operate. And St-MIPs reduced the production cost compared with Mt-MIPs. This study provides a new idea for natural product separation by molecular imprinting technology (MIT).