Molecularly Imprinted Polymers for the Selective Adsorption and Separation of Matrine

Sophora alopecuroides, a characteristic medicinal herb in Ningxia, is rich in medicinally valuable alkaloids. Among them, matrine (MAT) exhibits notable anti-inflammatory, antiviral, and anticancer activities. However, traditional separation and purification of MAT from the complex total alkaloid extract of S. alopecuroides often suffers from long processing time, poor selectivity, and reliance on toxic solvents. Therefore, we prepared a matrine-imprinted polymer (MAT@MIP) with moderate selectivity for MAT. MAT was used as the template, with 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and N-isopropylacrylamide (NIPAM) as functional monomers. The adsorption performance of MAT@MIP was enhanced by optimizing the experimental parameters. The kinetic results (35 °C, 40 min, 250 μg/mL) showed an apparent equilibrium adsorption capacity of 177.83 mg/g for MAT@MIP. When MAT@MIP was used as a solid-phase extraction sorbent to separate MAT from the real extract of S. alopecuroides, the MISPE dynamic adsorption capacity was 100.8 mg/g with a recovery of 79%. Compared with traditional methods, a notable advantage of this study is that the adsorption step can be performed in a pure aqueous phase under mild conditions. This strategy provides a reference method for the purification and separation of MAT from real samples and shows potential for practical application.