Synthesis of α-glucosidase-immobilized nanoparticles and their application in screening for α-glucosidase inhibitors

In order to rapidly and accurately screen compounds present in Chinese herbal medicines for α-glucosidase inhibition activity, we have developed a screening strategy which couples the immobilized enzymes with HPLC analysis. First, the core-shell PMMA/CS nanoparticle carrier was prepared by graft polymerization method. Subsequently, α-glucosidase was loaded on the nanoparticles to prepare the immobilized enzyme and construct a screening model. Secondly, the morphology and structure of the core-shell PMMA/CS material were characterized by transmission electron microscopy (TEM) and infrared spectroscopy (IR). The results indicate that the size distribution was uniform for the α-glucosidase-immobilized nanoparticles, with an average particle size of about 239   nm. Finally, the α-glucosidase-immobilized nanoparticles were used to screen α-glucosidase inhibitors from extracts of traditional Chinese medicine and from a mixture of pharmacologically active compounds. Extracts of traditional Chinese medicines were analyzed by HPLC method before and after incubation with the immobilized enzyme nanoparticles. Using this method, magnoflorine was selectively separated from methanol extracts of Magnoliae Officinalis Cortex and genistein was selectively separated from a mixture of isoflavone compounds. Both the two compounds have previously been reported to have α-glucosidase inhibitory activity. These results demonstrate that this screening strategy represents a rapid and highly efficient method for the identification of α-glucosidase inhibitors in complex extracts of Chinese herbal medicines.