Identification of novel triazolopyrimidines as potent α-glucosidase inhibitor through design, synthesis, biological evaluations, and computational analysis

Abstract

α-Glucosidase inhibitors are widely used in the management of type 2 diabetes mellitus (T2DM) by delaying carbohydrate digestion and reducing postprandial blood glucose levels. However, current drugs suffer from limited efficacy and gastrointestinal side effects, highlighting the need for novel inhibitors with improved potency and selectivity. In this study, a novel series of 5,7-diaryl-[1,2,4]triazolo[1,5-a]pyrimidin-6-amines 9a-9t was designed and prepared through an efficient, straightforward synthetic route. Subsequently, they were evaluated for their α-glucosidase inhibitory activity, with compound 9s exhibiting the most potent inhibition (IC₅₀ = 24.32 ± 0.18 µM), outperforming acarbose by over 30-fold. Enzyme kinetics revealed a competitive inhibition mode, and selectivity assays confirmed minimal α-amylase inhibition. Spectroscopic analyses (CD and fluorescence) demonstrated significant conformational changes in α-glucosidase upon ligand binding, suggesting structural stabilization and reduced flexibility. Molecular docking and 200-ns MD simulations confirmed persistent hydrophobic and halogen-bond interactions, particularly with residues Phe303, Arg315, and Gln182. Additionally, a BERT-based deep learning model with SMILES augmentation accurately predicted the biological activity of synthesized compounds, validating our computational pipeline. These findings highlight [1,2,4]triazolo[1,5-a]pyrimidines as promising scaffolds for the development of selective and potent α-glucosidase inhibitors.

Keywords: α-Glucosidase; Antidiabetic; Triazolopyrimidine; [1,2,4]Triazolo[1,5-a]pyrimidine.

Fig. 1

α-Glucosidase inhibitors containing 1,2,4-triazole core.

Fig. 2

Anti-diabetic agents bearing^1,2,4triazolo[1,5-a]pyrimidine core.

Scheme 1

The synthetic route for the preparation of targeted 5,7-diaryl-[1,2,4]triazolo[1,5-a]pyrimidin-6-amines 9.

Fig. 3

α-Glucosidase inhibition kinetics study: (A) the Lineweaver–Burk plot in the absence and presence of different concentrations of the triazolopyrimidine 9s; (B) the secondary plot between K_m and various concentrations of the triazolopyrimidine 9s.

Fig. 4

(a) Fluorescence spectroscopy of α-glucosidase in the presence of triazolopyrimidine 9s concentrations (0–25 µM) at phosphate buffer (100 mM, pH 6.8); (b) The inset shows the change in absorbance at 25 ℃ as a function of concentration of triazolopyrimidine 9s; (c) Fraction of unfolded α-glucosidase in various concentrations of triazolopyrimidine 9s at pH 6.8.

Fig. 5

Docking interaction profile of compound 9s.

Fig. 6

Protein and ligand RMSD trajectories over 200 ns. (A) Acarbose, (B) compound 9s.

Fig. 7

MM/GBSA binding free energy profiles of acarbose and compound 9s.

Fig. 8

Time series of gyration radius, surface areas, and intramolecular H‑bonds. (A) Acarbose, (B) compound 9s.

Fig. 9

Protein–ligand contact frequency histograms for compound 9s.

Fig. 10

Key ligand–protein interactions observed during the simulation trajectory.