Computational investigation to identify multi-targeted anti-hyperglycemic potential of substituted 2-Mercaptobenzimidazole derivatives and synthesis of new α-glucosidase inhibitors

Abstract

One of the most widespread diseases recognized all over the world is diabetes, accounting for 1.5 million deaths each year. Recent studies have demonstrated benzimidazole derivatives as potential antidiabetic agents. Hence, the present study is focused on designing new derivatives of 2-mercaptobenzimidazole by C-S cross-coupling reaction and are subjected to computational screening to identify the most promising candidate. Molecular docking and MM-GBSA calculations were performed to ascertain the binding potential with different antidiabetic targets, including α-glucosidase, PPaR-γ, DPP-4, and AMPK. We observed somewhat moderate binding interactions of the synthesized compound against the α-glucosidase. Since binding affinities can be improved using synthetic chemistry approaches, synthesis of analogues (A-18a-c) by designing hybrids at sites such as the acidic functionality of A-18 was done. The analogue A-18a, with p-fluorobenzyl substitution, exhibited enhanced binding affinity (-4.339 Kcal/mol) with the α-glucosidase compared to the parent compound (-3.827 Kcal/mol). The synthesized analogues were also subjected to an in-vitro α-glucosidase inhibitory assay. Among them, A-18a exhibited the most significant inhibitory potential, with an IC₅₀ value of 0.521 ± 0.01 µM as compared to the standard drug Acarbose (IC₅₀ 21.0 ± 0.5 µM). This aligns with the computational study findings, where A-18a exhibited stronger binding interactions within the active site of the enzyme. Hence, a promising analogue of the designed compound was synthesized through a computationally guided approach as an anti-hyperglycaemic agent. Additionally, most of the designed compounds showed significantly greater binding affinity with PPaR-γ as compared to the standard pioglitazone. A-18 was successfully synthesized by S-arylation reaction using CuI in 89% yield and was subjected to MD-simulation against PPaR-γ, which revealed stable binding throughout the 200 ns run. Future studies will focus on exploring the activity of the designed drugs against PPaR-γ through in-vitro and in-vivo assays.

Graphical Abstract

Graphical depiction of flow of study starting from drug designing and followed by the prediction of molecular targets, ligand binding and molecular dynamics.