Targeted enrichment of bruceine D from Brucea javanica by molecularly imprinted nanomagnetic sorbents

Objective: This study aimed to develop and validate a novel method for targeted enrichment of bruceine compounds, whose structural complexity hinders both synthesis and conventional natural extraction. As a case study, bruceine D, a major antitumor component from Brucea javanica (Yadanzi in Chinese), was selected for enrichment using magnetic nanoparticles (MNPs) functionalized with molecularly imprinted polymers (MIPs).

Methods: A comprehensive chemical profiling of the B. javanica extract was performed to identify bruceine D and its structural analogues. MNPs coated with bruceine D-MIPs (MMIPs) were synthesized and characterized using various techniques, including transmission electron microscopy to observe the morphology, scanning electron microscopy to analyze the surface structure, and Fourier-transform infrared spectroscopy to confirm the successful functionalization of MIPs on MNPs. The adsorption performance of MMIPs was assessed through static and dynamic adsorption experiments. Subsequently, the process was validated for selectivity, repeatability, and reusability. The adsorption data were modeled using the Freundlich isotherm and kinetic models to reveal the adsorption mechanism.

Results: Among multiple analogues, bruceine D was confirmed as a major constituent of the B. javanica extract. The MMIPs demonstrated superior morphology, crystallinity, and functional surface modification, leading to favorable adsorption characteristics. Compared to non-imprinted polymers, they exhibited significantly stronger adsorption intensity and selectivity for bruceine D due to a lower Freundlich isotherm constant (0.0418) and a higher imprinting factor (1.69). The MMIPs showed excellent repeatability with a low relative standard deviation (0.75 %) and maintained high extraction efficacy across multiple cycles. The MMIPs successfully isolated bruceine D from B. javanica extract, achieving a remarkable recovery yield (39.50 µg/g).

Conclusion: This study demonstrated a novel application of molecular imprinting technology targeting bruceine compounds. In particular, the MMIP-based selective enrichment of bruceine D from B. javanica showed superior efficiency, selectivity, and adsorption capacity compared to conventional methods. This advancement holds significant implications for natural product isolation, offering a sustainable and green strategy in the pharmaceutical industry for the isolation of complex bioactive compounds for therapeutic use.