Cerium-Based Metal-Organic Framework Nanocrystals for Colorimetric Screening of α-Glucosidase Inhibitors

The screening method for alpha-glucosidase (alpha-Glu) inhibitors plays a crucial role in the development of antidiabetic drugs. This study introduces cerium-based metal-organic framework (Ce-MOF) nanocrystals for the highly sensitive colorimetric detection of alpha-Glu inhibitors. The synthesized Ce-MOF nanocrystals exhibited excellent oxidase-like activity, efficiently catalyzing the oxidation of 3,3 ',5,5 '-tetramethylbenzidine (TMB) to generate a blue product (oxTMB) with a strong absorption peak at 652 nm, enabling quantitative analysis using spectroscopic techniques. Notably, hydroquinone (HQ) can reduce the blue oxTMB to the colorless TMB. Specifically, alpha-Glu can hydrolyze alpha-arbutin to generate HQ, which subsequently reduces the oxidase activity of Ce-MOF. However, the addition of alpha-Glu inhibitors in the system limited the production of HQ, thereby maintaining the oxidase-like activity stability of Ce-MOF. Leveraging this mechanism, a screening method for alpha-Glu inhibitors was developed. This method overcomes the limitations of the conventional p-nitrophenyl-alpha-d-glucopyranoside (p-NPG) assay and effectively avoids potential interference from hydrogen peroxide introduced by peroxidase-like nanomaterials, significantly enhancing the detection sensitivity. The reliability and accuracy of this method were validated, demonstrating the highly sensitive determination of acarbose with an IC(50 )value of 7.04 mu M and a detection limit of 3.2 nM. Moreover, this method has been successfully applied to screen potential alpha-Glu inhibitors from natural flavonoid compounds.