Novel heterocyclic organic compounds as DPP-4, α-amylase, and α-glucosidase inhibitors: Design, synthesis, and...

A series of novel N-substituted heterocyclic compounds were synthesized from various carbazide derivatives, and their structural characterization was carried out using FTIR, ¹H NMR, ¹³C NMR, and QTOF spectroscopic techniques. The in vitro inhibition activities of the compounds against DPP4, α-amylase, and α-glucosidase were evaluated using spectrophotometric methods, revealing that all compounds exhibited inhibitory effects on these enzymes. Notably, the compounds 3-(2,5-dimethoxyphenyl)-5-(4-methoxyphenyl)-2-phenyl-2,3-dihydro-1H-pyrazole (3a), 5-(2,5-dimethoxyphenyl)-3-(4-methoxyphenyl)-N-phenyl-4,5-dihydro-1H-pyrazole-1-carboxamide (3d), 3-(5-(3,5-dimethoxyphenyl)-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl)-4-hydroxy-2H-chromen-2-one (7a), and 5-(3,5-dimethoxyphenyl)-3-(4-hydroxy-2-oxo-2H-chromen-3-yl)-N-phenyl-4,5-dihydro-1H-pyrazole-1-carboxamide (7c) exhibited significant α-amylase inhibitory activity, with IC₅₀ values of 13.49 μM, 17.61 μM, 16.69 μM, and 22.09 μM, respectively. In addition to the in vitro studies, these compounds (3a, 3d, 7a, and 7c) were also subjected to molecular docking studies with α-amylase. Based on IC₅₀ values, compounds (3b) and (7a) exhibited potent inhibition of the DPP4 enzyme (20.08 μM and 22.51 μM, respectively), which was further investigated through molecular docking studies. Both in vitro and in silico findings concluded that the distribution of pharmacophore-related functional groups at distinct molecular sites enhances inhibitory efficacy, indicating that these novel compounds may possess potential as effective drug candidates for the treatment of type 2 diabetes.