Preparation of immobilized xanthine oxidase with magnetic metal-organic framework and its application in screening of active ingredients in traditional Chinese medicine.

Enzymes play a crucial role in the development and progression of various diseases, making them important targets for drug development. However, the stability issues associated with natural enzymes limit their broader application. Traditional methods for screening enzyme inhibitors from natural products are often time-consuming and labor-intensive. In this study, we designed and employed magnetic metal-organic frameworks (MOFs) to immobilize xanthine oxidase for the first time. By leveraging the porous structure and high specific surface area of MOFs, combined with the magnetic responsiveness of nanoparticles, we successfully developed a novel method for the efficient screening of potential enzyme inhibitors derived from natural products. By using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide (EDC/NHS) as a cross-linking agent, we achieved efficient immobilization of xanthine oxidase and identified baicalin as a potential inhibitor from the extract of Scutellaria baicalensis. In addition, we confirmed the adsorption capacity of this method for hordenine, demonstrated the specific adsorption of allopurinol, and also performed in vitro activity validation for baicalein. We not only successfully prepared the immobilized enzyme but also showcased that this method can efficiently screen and isolate potential enzyme inhibitors from traditional Chinese medicine, which provides a rapid and efficient new strategy for identifying enzyme inhibitors in natural products. This innovative approach offers a fresh perspective on the application of botanical medicine and the pharmacological treatment of hyperuricemia, which has important theoretical and practical significance. Graphical abstract Schematic diagram of synthesis of XO@MMOF (A) and ligand fishing process (B).