Silane-modified cellulose molecularly imprinted microspheres as solid-phase extraction sorbents for selective camptothecin isolation from Camptotheca acuminata crude extracts

CPT-enriching molecularly imprinted materials have been developed. • CCS-Si and MIP-CPT exhibit high selectivity for CPT. • The efficiency of the molecularly imprinted extraction column can reach 89.45%. Camptothecin (CPT), a potent anticancer quinoline alkaloid derived from plant resources, is conventionally purified through multi-step processes with low selectivity, high solvent consumption and unsatisfactory recovery. In this study, a novel bio-based surface-imprinted adsorbent (CCS-Si&MIP-CPT) was rationally designed and fabricated using porous cellulose-silica hybrid microspheres as the support matrix, with CPT as the template molecule and methacrylic acid as the functional monomer. The physicochemical structure of the as-prepared material was fully characterized, and its adsorption kinetics, isotherms, selective recognition mechanism and reusability were systematically investigated. Furthermore, the material was applied as a solid-phase extraction (SPE) filler for the purification of CPT from crude camptotheca seed extracts, and its performance was benchmarked against established purification methods. The results show that the adsorption behaviour of CCS-Si&MIP-CPT toward CPT is in good agreement with the Langmuir isotherm and the pseudo-second-order kinetic model. Combined with molecular structure comparison of CPT analogs, the selective recognition mechanism was comprehensively elucidated from three perspectives: hydrogen-bonding functional group matching, steric hindrance effect of substituents, and complementarity of molecular size and overall shape. The renewable carrier design and its cyclic stability not only show potential for application in green separation technologies for natural medicine development, but also provide a theoretical foundation for the high-value utilization of plant resources.