Rapid Screening and Identification of Antitumor Ingredients from the Mangrove Endophytic Fungus Using an Enzyme-Immobilized Magnetic Nanoparticulate System

As a consequence of recent progression in biomedicine and nanotechnology, nanoparticle-based systems have evolved as a new method with extensive applications in responsive therapy, multimodal imaging, drug delivery and natural product separation. Meanwhile, the magnetic nanoparticulate system has aroused great interest for separation and purification because of its excellent magnetic properties. Phospholipase A(2) (PLA(2)) is a highly expressed regulator to promote the growth of various cancers and is an ideal target to treat cancers. In this study, a novel strategy based on ligand-receptor interactions to discover novel PLA(2) inhibitors was established, in which PLA(2)-functionalized Fe3O4@PLGA-PEG-NH2 magnetic nanoparticles were used as a supporting material combined with high-performance liquid chromatography-mass spectrometry, aiming to accelerate the discovery of novel PLA(2) inhibitors from natural sources such as mangrove endophytic fungi. Under the optimized ligand fishing conditions, six target compounds were ultimately fished and identified to be cyclic peptides (1-3) and sterols (4-6), which compounds 1, 2 and 4-6 have well-documented cytotoxicities. Compound 3 exerted better inhibitory effect on A549 cells by experiment. In conclusion, PLA(2)-functionalized Fe3O4@PLGA-PEG-NH2 magnetic nanoparticles-based ligand fishing provided a feasible, selective and effective platform for the efficient screening and identification of antitumor components from natural products.