Synthesis, molecular modelling and pharmacological evaluation of novel indole-thiazolidinedione based hybrid analogues as potential pancreatic lipase inhibitors

Molecular mechanisms of naringin's high lipid-lowering activity: pancreatic lipase inhibition and fat accumulation reduction

BACKGROUND

Naringin, a natural flavonoid compound, has demonstrated potential anti-obesity effects by modulating lipid metabolism. Pancreatic lipase plays a critical role in lipid digestion and absorption, making it a key target for obesity management. This study investigated the inhibitory mechanism of naringin on pancreatic lipase through in vitro, in vivo, and in silico experiments.

RESULTS

In vitro experiments revealed that naringin was a competitive inhibitor of pancreatic lipase, with a half-maximal inhibitory concentration (IC₅₀) of 6.93 ± 0.12 mmol/L. Multi-fluorescence spectroscopy confirmed that naringin induced secondary structure changes and static fluorescence quenching of pancreatic lipase, with a binding constant of 2.16 × 104 L/mol. Isothermal titration calorimetry indicated a spontaneous exothermic reaction (-26.08 kJ/mol), mainly driven by hydrogen bonding and electrostatic force. In vivo studies demonstrated that naringin decreased serum lipase activity by 24.54%, mitigated hepatic lipid accumulation, and down-regulated inflammatory cytokines in high-fat diet-induced obese rats. Molecular simulation further revealed that hydrogen bonding was the primary interaction force between naringin and pancreatic lipase.

CONCLUSIONS

Naringin effectively inhibits pancreatic lipase through competitive binding and structural modifications, reducing lipid digestion and absorption. The inhibitory effect of naringin on pancreatic lipase might provide new insights into the role of naringin in lipid metabolism regulation and potential application in obesity management. © 2025 Society of Chemical Industry.

Discover the Power of Lithospermic Acid as Human Carbonic Anhydrase VA and Pancreatic Lipase Inhibitor Through In Silico and In Vitro Studies

Obesity remains a significant global health concern, with limited pharmacological options that balance efficacy and safety. In this study, we identified lithospermic acid (LTS0059529) from Salvia miltiorrhiza as a potential dual inhibitor of pancreatic lipase (PL) and human carbonic anhydrase VA (hCA VA), two key enzymes in lipid metabolism. Using molecular docking and dynamics simulations, we observed that lithospermic acid interacts with Zn²⁺ in hCA VA via its benzofuran carboxylate moiety and forms stable complexes with PL through hydrogen bonding with ASP 205 and π-stacking interactions with PHE 77 and PHE 215. Experimental validation confirmed its inhibitory activity, with Ki values of 33.1 ± 1.6 μM for PL and 0.69 ± 0.01 μM for hCA VA. While its inhibition of hCA VA is not isoform-specific, lithospermic acid demonstrates significant potential as a dual inhibitor, targeting complementary pathways in obesity management. This study is the first to explore its dual action on PL and hCA VA, highlighting a promising strategy for future antiobesity therapies. Further research will focus on optimizing selectivity and potency to develop safer and more effective treatments.

Coumarin Analogues as Promising Anti-Obesity Agents: In Silico Design, Synthesis, and In Vitro Pancreatic Lipase Inhibitory Activity

A set of coumarin-3-carboxamide analogues were designed, synthesized, and evaluated for their ability to impede pancreatic lipase (PL) activity. Out of all the analogues, 5dh and 5de demonstrated promising inhibitory activity against PL, as indicated by their respective IC50 values of 9.20 and 11.4 μM, as compared to Orlistat (IC50 = 0.97 μM). It was found that analogue 5dh inhibited PL in a competitive manner with an inhibition constant (Ki) of 4.504 μM. Additionally, the docking analysis validated the interactions between the analogue 5dh (MolDock score of -140.251 kcal/mol) and key amino acids in the active site, including Leu 153, Gly 76, Arg 256, His 151, Phe 77, and His 263. The inhibitory activity of these analogues was significantly correlated with their MolDock scores (Pearson's r = 0.6586). Finally, molecular dynamics simulation was also performed for 100 ns in order to elucidate the stability, confirmation and intermolecular interactions of the active analogue 5dh. The results of this investigation suggested that the complex maintained its stability despite the dynamic conditions exhibiting interactions with important amino acids. In summary, the outcomes indicated that the synthesized analogues exhibited the potential to inhibit PL activity.

Exploration of the Mechanism of Guaijaverin in Inhibiting Pancreatic Lipase Based on Multispectral Method, Molecular Docking, and Oral Lipid Tolerance Test in Rats

This study aims to investigate the action mechanism of guaijaverin on pancreatic lipase from multiple perspectives and provide a theoretical basis for the search for new pancreatic lipase inhibitors. The inhibition of pancreatic lipase by guaijaverin was investigated through enzyme inhibition activity experiments, and the IC50 was calculated to determine the type of inhibition of guaijaverin. The mechanism of action was studied by measuring fluorescence, ultraviolet spectra, and circular dichroism. Molecular docking technology was used to explore the binding situation. In addition, in vivo oral lipid tolerance tests in rats were carried out to investigate the inhibitory effect of guaijaverin on pancreatic lipase. Guaijaverin inhibited pancreatic lipase up to 90.63%, confirming its excellent inhibitory ability. The inhibition type was noncompetitive inhibition in reversible inhibition. The multispectral experiments indicated that its quenching type was static quenching and guaijaverin changed the microenvironment and spatial conformation of pancreatic lipase. The molecular docking results showed that the minimum binding energy between the two compounds was -6.96 kcal/mol. In vivo experiments demonstrated that guaijaverin inhibits pancreatic lipase by reducing TG uptake in the body. Guaijaverin has excellent inhibitory effects on pancreatic lipase and has the potential to function as a pancreatic lipase inhibitor.

Thiazolidine-2,4-dione hybrids as dual alpha-amylase and alpha-glucosidase inhibitors: design, synthesis, in vitro and in vivo anti-diabetic evaluation

Twelve 3,5-disubstituted-thiazolidine-2,4-dione (TZD) hybrids were synthesized using solution phase chemistry. Continuing our previous work, nine O-modified ethyl vanillin (8a-i) derivatives were synthesized and reacted with the TZD core via Knoevenagel condensation under primary reaction conditions to obtain final derivatives 9a-i. Additionally, three isatin-TZD hybrids (11a-c) were synthesized. The intermediates and final derivatives were characterized using 1H and 13C NMR spectroscopy, and the observed chemical shifts agreed with the proposed structures. The in vitro alpha-amylase and alpha-glucosidase inhibitory evaluation of newly synthesized derivatives revealed compounds 9F and 9G as the best dual inhibitors, with IC50 values of 9.8 ± 0.047 μM for alpha-glucosidase (9F) and 5.15 ± 0.0017 μM for alpha-glucosidase (9G), 17.10 ± 0.015 μM for alpha-amylase (9F), and 9.2 ± 0.092 μM for alpha-amylase (9G). The docking analysis of synthesized compounds indicated that compounds have a higher binding affinity for alpha-glucosidase as compared to alpha-amylase, as seen from docking scores ranging from -1.202 to -5.467 (for alpha-amylase) and -4.373 to -7.300 (for alpha-glucosidase). Further, the molecules possess a high LD50 value, typically ranging from 1000 to 1600 mg kg-1 of body weight, and exhibit non-toxic properties. The in vitro cytotoxicity assay results on PANC-1 and INS-1 cells demonstrated that the compounds were devoid of significant toxicity against the tested cells. Compounds 9F and 9G showed high oral absorption, i.e., oral absorption >96%, and their molecular dynamics simulation yielded results closely aligned with the observed docking outcomes. Finally, compounds 9F and 9G were evaluated for in vivo antidiabetic assessment by the induction of diabetes in Wistar rats using streptozotocin. Molecule 9G has been identified as the most effective anti-diabetic molecule due to its ability to modulate several biochemical markers in blood plasma and tissue homogenates. The results were further confirmed by histology investigations conducted on isolated pancreas, liver, and kidney.

Synthesis and Characterization of Short α and β-Mixed Peptides with Excellent Anti-Lipase Activities

Obesity is a source of significant pathologies and deadly diseases, including heart disease, diabetes, and cancer. One of the most intriguing strategies in the hunt for new anti-obesity medications is the inhibition of pancreatic lipase (PL). This study presents a novel application of short α and β-mixed peptides as pancreatic lipase inhibitors. These peptides were synthesized in the solution phase and characterized using FTIR and 1H-NMR. L-proline is present in a high percentage of natural anti-lipase peptides and was used as a β-amino acid in this study to enhance anti-lipase activity and proteolytic stability. Moreover, L-α-proline was converted to β-amino acid derivatives using the Arndt-Eistert method with the advantage of stereo control at the α-carbon. The synthesized peptides with anti-lipase activity are N-Boc-β-Pro-Gly-OBz (93%), N-Boc-O-Bz-Tyr-β-Pro-β-Pro-Gly-OBz (92%), N-Boc-O-Bz-Tyr-β-Pro-COOH (91%), N-Boc-Phe-β-Pro-OCH3 (90%), and N-Boc-O-Bz-Tyr-β-Pro-OCH3 (89%). These peptides may function as lead molecules for further modification to more significant molecules, which can help control obesity.

Discovery of thiazolidinedione-based pancreatic lipase inhibitors as anti-obesity agents: synthesis, in silico studies and pharmacological investigations

A series of new 2,5-disubstituted arylidene derivatives of thiazolidinedione (16a-e, 17a-d, 18a-c) designed using molecular hybridization approach were synthesized, structurally characterized, and explored for their anti-obesity potential via inhibition of Pancreatic Lipase (PL). Compound 18a presented the most potent PL inhibitory activity with IC50 = 2.71 ± 0.31 µM, as compared to the standard drug, Orlistat (IC50 = 0.99 µM). Kinetic study revealed reversible competitive mode of enzyme inhibition by compound 18a with an inhibitory constant value of 1.19 µM. The most promising compound 18a revealed satisfactory binding mode within the active site of the target protein (human PL, PDB ID: 1LPB). Also, MM/PBSA binding free energy and molecular dynamics (MD) simulation analysis were performed for the most promising compound 18a, which showed potent inhibition according to the results of in vitro studies. Furthermore, a stable conformation of the 1LPB-ligand suggested the stability of this compound in the dynamic environment. The ADME and toxicity analysis of the compounds were examined using web-based online platforms. Results of in vivo studies confirmed the anti-obesity efficacy of compound 18a, wherein oral treatment with compound 18a (30 mg/kg) resulted in a significant reduction in the body weight, BMI, Lee index, feed intake (in Kcal), body fat depots and serum triglycerides. Compound 18a significantly decreased the levels of serum total cholesterol (TC) to 128.6 ± 0.59 mg/dl and serum total triglycerides (TG) to 95.73 ± 0.67 mg/dl as compared to the HFD control group. The present study identified disubstituted TZD derivatives as a new promising class of anti-obesity agents.