Application of Molecularly Imprinted Polymers in Plant Natural Products: Current Progress and Future Perspectives

Plants, as a large and complex system, are rich in a variety of natural bioactive constituents. It is crucial to enrich, isolate, purify and detect these natural products. Molecularly imprinted polymers (MIPs) are a class of polymers prepared by molecularly imprinted technology (MIT) that have specific recognition sites and are complementary to templates in shape, size, and binding groups. The synthesis and polymerization mechanism of MIPs are introduced. A variety of preparation methods for MIPs have been developed. MIPs can be classified into three types: non‐covalent molecularly imprinted, covalent molecularly imprinted, and semi‐covalent molecularly imprinted. MIPs usually consists of five parts: template, functional monomer, cross‐linker, initiator, and solvent/reagent. With the advantages of high‐specificity binding ability, MIPs have shown excellent efficacy in the separation, enrichment, and purification of plant active products, such as flavonoids, polyphenols, terpenoids, and other components, especially as specific adsorbent materials. Due to the high selectivity to target the analytes, MIPs have also been used as sensors to detect the bioactive constituents in plants. Undeniably, MIPs still face undeniable limitations in the application of plant natural products. The development of MIPs with high selectivity, strong affinity, cost‐effectiveness, sensitivity, and environmental friendliness are valuable and promising. Molecularly imprinted polymers are very popular because of their specific recognition function. The mechanism, polymerization method, classification, and composition of molecularly imprinted polymers have been reviewed in this paper. This paper focuses on the application of molecularly imprinted polymers in the purification and detection of plant natural bioactive constituents.