New carbazole-5-phenoxymethyl-1,2,4-triazole derivatives as multi-target inhibitors towards α-glucosidase, α-amylase and PTP1B: Construction, biological evaluation, and mechanism investigation.

With the aim of developing novel multi-target agents capable of simultaneously inhibiting α-glucosidase (α-Glu), α-amylase (α-Amy), and protein tyrosine phosphatase 1B (PTP1B), a new library of twenty-four carbazole-5-phenoxymethyl-1,2,4-triazole analogues (7a-7x) was synthesized and subjected to enzyme inhibition screening. The bioassay results demonstrated that all derivatives possessed potent anti-α-glucosidase (IC50: 6.68 ± 0.05 - 35.89 ± 0.68 μM) and anti-α-amylase (IC50: 4.08 ± 0.09 - 21.37 ± 0.72 μM) properties, significantly superior to acarbose (IC50 = 165 ± 4 μM and 20.76 ± 0.29 μM, respectively). Among all tested compounds, 7w displayed the strongest dual inhibition toward α-Glu (IC50 = 6.68 ± 0.05 μM) and α-Amy (IC50 = 4.41 ± 0.15 μM). Meanwhile, its activity against PTP1B (IC50 = 3.49 ± 0.57 μM) was found to be on a par with positive ursolic acid (IC50 = 3.18 ± 0.25 μM). Further mechanistic investigations, including kinetic assays, molecular docking, and multispectral analyses, revealed that compound 7w inhibited α-Glu, α-Amy, and PTP1B activities through binding to the target enzymes, involving non-covalent interactions and altering their secondary structures. Meanwhile, 7w was found to effectively reduce murine post-meal glycemic concentrations and exhibited no apparent cytotoxicity. Collectively, these target compounds hold promise as lead scaffolds in the rational design of new multi-target therapeutics for diabetes mellitus.