Indoleamine 2,3 dioxygenase 1 immobilization on magnetic nanoparticles for screening inhibitors from coffee.

In this study, a ligand fishing method was developed to screen potential indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors from coffee extracts by immobilization of IDO1 enzyme on amino-modified magnetic nanoparticles combined with UHPLC-Q-TOF-MS/MS analysis. Parameters including enzyme concentration, immobilization time, the pH of glutaraldehyde and the amount of magnetic nanoparticles were optimized. The results indicated that immobilized IDO1 could be reused 5 times and was stable during storage for 7 days. Several IDO1 ligands were captured by incubating immobilized IDO1 with coffee extract, of which 10 showed an obvious difference comparing to non-conjugated bare nanoparticles. In vitro inhibitory activity was further performed by CE analysis, in which ferulic acid and chlorogenic acid had better IDO1 inhibitory activity, with IC50 value of 113.7 µM and 307.5 µM. These results demonstrate that this method provides an effective platform for identifying and screening IDO1 inhibitors from natural products.

Off-line and on-line liquid chromatography-mass spectrometry methods with immobilized bio-macromolecules for drug screening from natural sources.

Natural products are an important source of major compounds in drug discovery. Currently, rapid screening and identification of bioactive compounds is a challenge due to the complicated chemical composition of natural products. Affinity screening methods based on liquid chromatography coupled with mass spectrometry have seen increasing interest in the past few years. In this review, the various strategies are classified into off-line and on-line modes. The principles and applications of these screening methods such as magnetic nanoparticles, affinity solid-phase extraction, immobilized liposome chromatography and cell membrane chromatography are introduced. This review covers the research advances of LC-MS based screening methods from 2019 to mid 2022, discussing their advantages and disadvantages, and providing an outlook for the future of this field.

Determination of pesticide residues in chilli and Sichuan pepper by high performance liquid chromatography quadrupole time-of-flight mass spectrometry.

In this study, a multi-component analytical method for the detection of pesticide residues in chilli and Sichuan pepper by high performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (LC-Q-TOF/MS) was developed and validated. The sample preparation is based on an extraction step with acetonitrile followed by a cleanup step using primary secondary amine, C18, graphitized carbon black and anhydrous magnesium sulfate. Values of matrix effects ranged from -55.8 to 26.0 % for chilli, and -69.1 to 24.0 % for Sichuan pepper. The LOQ of ≤ 5 µg kg-1 was achieved for all the target pesticides. Applying the method to real samples, some pesticides were found at high concentrations, which were beyond the MRL set by the EU. The results showed that the developed method could be used for the quantitative analysis of target pesticides and non-target screening for potential metabolites in chilli and Sichuan pepper.