Design, synthesis, in silico molecular modelling studies and biological evaluation of novel indole-thiazolidinedione hybrid analogues as potential pancreatic lipase inhibitors

Abstract

Pancreatic lipase (PL) is a key enzyme responsible for the digestion of dietary triglycerides; hence its inhibition is considered as a promising target for the management and/or treatment of obesity. A new series of indole-thiazolidinedione (TZD) hybrid analogues were synthesized using a molecular hybridisation approach and evaluated for their anti-obesity effects via PL inhibition. The targeted analogues were synthesized via the condensation reaction between various substituted isatin with TZD in the presence of aqueous KOH in methanol. Amongst the synthesized analogues, 7k and 7m exhibited a potential PL inhibitory activity (IC₅₀ – 7.30 and 9.51 μM, respectively). Kinetic study of these potent analogues revealed their competitive mode of enzyme inhibition. This fact was confirmed via fluorescence spectroscopy which further suggested the presence of one binding site for the synthesized analogues. Molecular docking of the synthesized analogues was performed using human PL (PDB ID: 1LPB). The obtained MolDock scores were aligned with the in vitro PL inhibitory activity (Pearson's r = 0.9108, p < 0.05). Moreover, a stable conformation of the 1LPB-ligands suggested the stability of these complexes in the dynamic environment. These studies provided a basis for the potential role of the indole-TZD hybrids in PL inhibition and further optimization might result in the development of new lead candidates for obesity treatment.