A fluorescence strategy for monitoring α-glucosidase activity and screening its inhibitors from Chinese herbal medicines based on Cu nanoclusters with aggregation-induced emission


Herein, the self-assembly of 1-dodecanethiol-capped Cu nanoclusters (DT-Cu NCs) is obtained by annealing of dibenzyl ether solution of nanoclusters. These aggregates are composed of small clusters and emit a high level of aggregation-induced emission (AIE) in water. Based on the quenching effect of 4-nitrophenol (4-NP) on DT-Cu NCs, a fluorescence strategy is developed to monitor α-glucosidase (α-Glu) activity and screen its inhibitors from Chinese herbal medicines. 4-Nitrophenyl-α-D-glucopyranoside (NGP) is selected as the substrate, which is further hydrolyzed to yield 4-NP through the catalysis of α-Glu. The quenching efficiency is positively correlated to the concentration of α-Glu. Furthermore, the inhibitory effects of the extracts from four Chinese herbal medicines (i.e., the rind of Punica granatum L., Momordica grosvenorii Swingle., Crataegus pinnatifida Bge., and Lycium barbarum L.) on the α-Glu activity have been studied. The IC50 values of extracts from the rind of Punica granatum L. and Momordica grosvenorii Swingle are 0.23 and 0.37 g/L, respectively, so they show obvious inhibitory effects on α-Glu. The extracts of Crataegus pinnatifida Bge. and Lycium barbarum L. exhibit relatively weak inhibitory effects. Hence, the proposed strategy can be applicable for screening α-Glu inhibitors from Chinese herbal medicines. Last but not the least, by immobilizing DT-Cu NCs into agarose hydrogels in polyethylene tubes, a visual device is fabricated to screen α-Glu inhibitors with high throughput and sensitivity.

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This work was supported by the National Natural Science Foundation of China (No. 21775088, 21705095), the Natural Science Foundation of Shandong Province, China (ZR2019QB010), and the Scientific Research Foundation of Qufu Normal University (BSQD20130117).

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Correspondence to Fei Qu or Xian-En Zhao.

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The human serum sample experiments were performed in accordance with the guidelines from the Ethical Committee, Qufu Normal University. All serum samples were obtained from healthy volunteers with their informed consent. All studies were approved by the Ethical Committee of Qufu Normal University.

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Li, C., Zi, Y., Xu, D. et al. A fluorescence strategy for monitoring α-glucosidase activity and screening its inhibitors from Chinese herbal medicines based on Cu nanoclusters with aggregation-induced emission. Anal Bioanal Chem (2021). https://doi.org/10.1007/s00216-021-03214-w

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  • α-Glucosidase
  • Inhibitor screening
  • Chinese herbal medicines
  • Inner filter effect
  • Copper nanoclusters
  • Aggregation-induced emission