Identification of enzyme inhibitors using therapeutic target protein–magnetic nanoparticle conjugates

Target protein–magnetic nanoparticle (MNP) conjugates, i.e. α-glucosidase–MNP and protein tyrosine phosphatase 1B (PTP1B)–MNP, were prepared and evaluated for the first time for affinity extraction of enzyme inhibitors from herbal extracts. Four ligands extracted from Granati pericarpium were identified by ESI-MS analysis. In vitro tests indicated that they inhibited both α-glucosidase and PTP1B, two important target proteins for diabetic treatment.