Search Results (4)

A novel screening platform based on an Fe₃O₄@C@PDA-Ni²⁺@COX-2 ligand fishing combination with high-performance liquid chromatography–mass spectrometry was first designed, synthesized, and employed to screen and identify COX-2 inhibitors from Panax notoginseng leaves. The obtained magnetic nanoparticles exhibit outstanding preconcentration ability that allows for controlling the enzyme orientation to avoid enzyme active site blocking, conformational changes, or denaturing during immobilization. The as-prepared Fe₃O₄@C@PDA-Ni²⁺@COX-2 composite was carefully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectrometry (FT-IR), Xray powder diffraction (XRD), thermal gravimetric analyzer (TGA), vibrating sample magnetometer (VSM), and Zeta potential analysis. The analytical parameters influencing the magnetic solid-phase fishing efficiency were optimized by univariate and multivariate methods (Box–Behnken design) by testing a positive control and celecoxib with active and inactive COX-2. Under the optimized ligand fishing conditions, twelve potential COX-2 inhibitors were screened and characterized in Panax notoginseng leaves. The results indicate that the proposed method provides a simple, feasible, selective, and effective platform for the efficient screening and identification of active compounds from Chinese herbal medicine. It has guiding significance for the synthesis and development of novel anti-inflammatory drugs, and provides a reference for the efficient discovery of anti-inflammatory drugs or lead compounds from the complex system of Chinese herbal medicine. Full article

How to rapidly and accurately screen bioactive components from complex natural products remains a major challenge. In this study, a screening platform for pancreatic lipase (PL) inhibitors was established by combining magnetic beads-based ligand fishing and high-resolution bioassay profiling. This platform was well validated using a mixture of standard compounds, i.e., (-)- epigallocatechin gallate (EGCG), luteolin and schisandrin. The dose–effect relationship of high-resolution bioassay profiling was demonstrated by the standard mixture with different concentrations for each compound. The screening of PL inhibitors from green tea extract at the concentrations of 0.2, 0.5 and 1.0 mg/mL by independent high-resolution bioassay profiling was performed. After sample pre-treatment by ligand fishing, green tea extract at the concentration of 0.2 mg/mL was specifically enriched and simplified, and consequently screened through the high-resolution bioassay profiling. As a result, three PL inhibitors, i.e., EGCG, (-)-Gallocatechin gallate (GCG) and (-)-Epicatechin gallate (ECG), were rapidly identified from the complex matrix. The established platform proved to be capable of enriching affinity binders and eliminating nonbinders in sample pre-treatment by ligand fishing, which overcame the technical challenges of high-resolution bioassay profiling in the aspects of sensitivity and resolution. Meanwhile, the high-resolution bioassay profiling possesses the ability of direct bioactive assessment, parallel structural analysis and identification after separation. The established platform allowed more accurate and rapid screening of PL inhibitors, which greatly facilitated natural product-based drug screening. Full article

Due to the expanding occurrence of marine toxins, and their potential impact on human health, there is an increased need for tools for their rapid and efficient detection. We give an overview of the use of magnetic beads (MBs) for the detection of marine toxins in shellfish and fish samples, with an emphasis on their incorporation into electrochemical biosensors. The use of MBs as supports for the immobilization of toxins or antibodies, as signal amplifiers as well as for target pre-concentration, is reviewed. In addition, the exploitation of MBs in Systematic Evolution of Ligands by Exponential enrichment (SELEX) for the selection of aptamers is presented. These MB-based strategies have led to the development of sensitive, simple, reliable and robust analytical systems for the detection of toxins in natural samples, with applicability in seafood safety and human health protection. Full article

Identification of active compounds from natural products is a critical and challenging task in drug discovery pipelines. Besides commonly used bio-guided screening approaches, affinity selection strategy coupled with liquid chromatography or mass spectrometry, known as ligand fishing, has been gaining increasing interest from researchers. In this review, we summarized this emerging strategy and categorized those methods as off-line or on-line mode according to their features. The separation principles of ligand fishing were introduced based on distinct analytical techniques, including biochromatography, capillary electrophoresis, ultrafiltration, equilibrium dialysis, microdialysis, and magnetic beads. The applications of ligand fishing approaches in the discovery of lead compounds were reviewed. Most of ligand fishing methods display specificity, high efficiency, and require less sample pretreatment, which makes them especially suitable for screening active compounds from complex mixtures of natural products. We also summarized the applications of ligand fishing in the modernization of Traditional Chinese Medicine (TCM), and propose some perspectives of this remarkable technique. Full article