Catalyst-Free Synthesis, in vitro Biological Evaluation and in silico Molecular Docking Studies on a Series of Tosylurea-linked Heterocyclic Analogues as a-Glucosidase Inhibitors

Insulin resistance, caused by hyperglycemia, the leading cause of the global prevalence of type 2 diabetes. According to recent WHO statistics, 422 million people worldwide suffer from diabetes. α-Glucosidase inhibitors are effective in improving the metabolic profile of patients with type 2 diabetes. The introduction of green chemistry into chemical society has led to the rapid establishment of organic synthesis without catalyst. Hence, a series of tosylurea-linked heterocyclic analogues C1-C9 were synthesized in catalyst-free conditions and their physical (state, colour, melting point) and spectral (FT-IR, 1H NMR, 13C NMR and ESI-HRMS) properties were determined. All compounds were studied in silico and in vitro experiments to assess their bioactive potential as α-glucosidase inhibitors. The in silico molecular docking studies were conducted using Schrödinger Glide software against human α-glucosidase enzyme target (PBD: 3L4W) to identify the virtual binding profile of compounds C1-C9, respectively in relative comparison to the co-crystallized clinically approved α-glucosidase inhibitor. The in vitro α-glucosidase screening assay was performed to identify the hit molecule among C1-C9, the results were compared with a standard drug, voglibose. The observed in silico and in vitro results were consistent and relatively comparable that identified C7 as bioactive hit that demonstrated most stable binding properties at the target site. The observed activity of C7 is primarily due to the synergistic or addition potential of the pharmacophores pyridine and sulfonylurea hybridized into one molecule. The structural analogues of these pharmacophores were earlier proven with potential α-glucosidase inhibitory properties.