Novel 1H-pyrrole-2,5-dione derivatives as potential anti-diabetic agents: design, synthesis, in vitro, in ovo, and molecular docking studies

Diabetes mellitus (DM) is the most common metabolism-related health problem across the world and new therapeutics are still emerging into the market. One of the treatments is the inhibition of α-glucosidase, which is a validated therapeutic strategy for mitigating postprandial hyperglycemia in Type 2 DM. However, the clinical utility of current inhibitors, such as Acarbose, is often limited by gastrointestinal side effects and suboptimal pharmacokinetics linked to their surface-binding modes. In this study, we reported the design, synthesis, and biological evaluation of a novel series of 1H-Pyrrole-2,5-dione derivatives, targeting the deep catalytic cleft of human acid α-glucosidase (rhGAA). In vitro studies revealed that all the new compounds showed higher enzyme inhibitory activity than Acarbose (IC₅₀ = 54.14 ± 6.43 mM) except 3e, 3f, and 5d. In in ovo model, compound 3d worked best to reduce blood glucose levels (around 48 mg/mL) and maintained this effect within 3 h. Molecular docking calculations covering the whole protein surface confirmed the catalytic pocket as the primary binding site, followed by focused docking, which identified 3g as the top in silico hit (−9.35 kcal/mol). In vitro kinetic experiments revealed that 5c possessed the highest inhibitory potential (IC₅₀ = 0.21 mM) and performed significantly better than Acarbose, while structural dynamics analysis of 5c highlighted its conformational instability. Consequently, compound 3d (IC₅₀ = 0.64 mM) was selected as the lead candidate to effectively inhibit rhGAA. Structural fingerprinting elucidated a unique “Anchor Mechanism” for 3d, characterized by a critical hydrogen bond with ARG281.