NMR-based screening for natural product subfraction to precisely identify ligand of target protein

Introduction The inherent diversity of natural product extracts has not only made their value for biological activity attractive, but has also presented significant challenges for separation and detection techniques to enable rapid characterisation of the biologically active component present in the complicated mixture. Objective Nuclear magnetic resonance (NMR) is routinely valued for its ability to shed light on molecular structure, when NMR is used as a promising tool in drug screening, it can detect and quantify molecular interactions, and at the same time provide detailed structural information with atomic level resolution. Here, we introduced an accurate and efficient strategy for discovering ligands from natural product extracts, by taking the advantage of NMR-based drug screening. Methodology The characteristic pre-purified subfraction libraries were brought into screening, and combinatorial ligand-observed NMR interaction detection experiments were performed, once hits were found from one subfraction, the repository of the subfraction would be subject to separation and preparation, and the structure of the hits would be easily identified. Results Screening procedure of Radix Polygoni Multiflori water extract against human serum albumin (HSA) was used as an example, to discuss and verify the detailed methodology. Furthermore, human fatty acid binding protein 4 (FABP(4)) was presented as an example target protein, to illustrate the utility of this method for discovering biologically active component. Conclusions It is proved that suitable subfraction library and well-combined ligand-detected NMR experiments will make the screening streamline more accurate and efficient. NMR is a promising tool to integrate natural product extracts into modern drug screening.