Potent Pancreatic Lipase Inhibitors Research Articles

Exploring flavonoid derivatives as potential pancreatic lipase inhibitors for obesity management: An in silico and in vitro study.

Obesity is widely recognized as a major public health issue and is one of the leading causes of death worldwide. Overweight and obesity are prominent lifestyle ailments that not only give rise to additional health issues but also play a role in the development of other chronic diseases, such as cancer, diabetes, metabolic syndrome, and cardiovascular diseases. Orlistat is now the only pharmaceutical drug for the management of obesity. However, prolonged use of orlistat has been associated with detrimental consequences, hence necessitating the development of a new drug with reduced or no adverse reactions. Pancreatic Lipase is a critical enzyme in lipid metabolism. Using naturally occurring compounds as PL inhibitors has garnered significant attention because of their diverse structure and low toxicity. The present work investigates the inhibitory action of flavonoids on PL using in silico and in vitro methods. Thirteen flavonoid derivatives and orlistat were docked with PL. The ADME properties of the flavonoid derivatives were studied, and most of the compounds are in admire range. The stability of the best-docked complexes was checked by REMD. The in silico study demonstrated favorable inhibitory activity of flavonoids compared to orlistat. Consequently, an enzyme inhibitory experiment was conducted to authenticate the in silico results. The lipase inhibitory activity was assessed by using p-nitrophenyl butyrate as the substrate. Kaempferol exhibited significant inhibitory activity against PL, as shown by its IC50 value of 72.7 ± 3µM. This study proposed a natural drug candidate with promising inhibitory efficacy against PL for obesity.

Discovery of Curcuminoids as Pancreatic Lipase Inhibitors from Medicine-and-Food Homology Plants.

Researchers are increasingly interested in discovering new pancreatic lipase inhibitors as anti-obesity ingredients. Medicine-and-food homology plants contain a diverse set of natural bioactive compounds with promising development potential. This study screened and identified potent pancreatic lipase inhibitors from 20 commonly consumed medicine-and-food homology plants using affinity ultrafiltration combined with spectroscopy and docking simulations. The results showed that turmeric exhibited the highest pancreatic lipase-inhibitory activity, and curcumin, demethoxycurcumin, and bisdemethoxycurcumin were discovered to be potent pancreatic lipase inhibitors within the turmeric extract, with IC50 values of 0.52 ± 0.04, 1.12 ± 0.05, and 3.30 ± 0.08 mg/mL, respectively. In addition, the enzymatic kinetics analyses demonstrated that the inhibition type of the three curcuminoids was the reversible competitive model, and curcumin exhibited a higher binding affinity and greater impact on the secondary structure of pancreatic lipase than found with demethoxycurcumin or bisdemethoxycurcumin, as observed through fluorescence spectroscopy and circular dichroism. Furthermore, docking simulations supported the above experimental findings, and revealed that the three curcuminoids might interact with amino acid residues in the binding pocket of pancreatic lipase through non-covalent actions, such as hydrogen bonding and π-π stacking, thereby inhibiting the pancreatic lipase. Collectively, these findings suggest that the bioactive compounds of turmeric, in particular curcumin, can be promising dietary pancreatic lipase inhibitors for the prevention and management of obesity.

Biaryl carboxamide-based peptidomimetics analogs as potential pancreatic lipase inhibitors for treating obesity.

A series of 1,1'-biphenyl-3-carboxamide and furan-phenyl-carboxamide analogs were synthesized using an optimized scheme and confirmed by 1H and 13C nuclear magnetic resonance and high-resolution mass spectrometry techniques. The synthesized peptidomimetics analogs were screened in vitro to understand the inhibitory potential of pancreatic lipase (PL). Analogs were assessed for the PL inhibitory activity based on interactions, geometric complementarity, and docking score. Among the synthesized analogs, 9, 29, and 24 were found to have the most potent PL inhibitory activity with IC50 values of 3.87, 4.95, and 5.34 µM, respectively, compared to that of the standard drug, that is, orlistat, which inhibits PL with an IC50 value of 0.99 µM. The most potent analog, 9, exhibited a competitive-type inhibition with an inhibition constant (Ki) of 2.72 µM. In silico molecular docking of analog 9 with the PL (PDB ID:1LPB) showed a docking score of -11.00 kcal/mol. Analog 9 formed crucial hydrogen bond interaction with Ser152, His263, π-cation interaction with Asp79, Arg256, and π-π stacking with Phe77, Tyr114 at the protein's active site. The molecular dynamic simulation confirmed that analog 9 forms stable interactions with PL at the end of 200 ns with root mean square deviation values of 2.5 and 6 Å. No toxicity was observed for analog 9 (concentration range of 1-20 µM) when tested by MTT assay in RAW 264.7 cells.

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

A series of novel indole-thiazolidinedione hybrid analogues (7a to 7 u) were synthesised, characterised and evaluated for their potential Pancreatic Lipase (PL) inhibition. Amongst the screened analogues, 7r was found to be the most active PL inhibitor with an IC50 of 2.67 µM. Furthermore, enzyme inhibition kinetics study revealed a competitive mode of inhibition by the analogues. This fact was confirmed via fluorescence spectroscopy which further suggested the presence of one binding site for the synthesized analogues. Molecular docking was performed using human PL (PDB ID: 1LPB) and were in agreement with the in vitro results (Pearson’s r = 0.8355, p < 0.05). A molecular dynamics study (100 ns) indicated that 7r was stable in a dynamic environment. The analogue 7r exhibited potential antioxidant activity and was devoid of cytotoxic effect on RAW 264.7 cells. Based on the in-vitro profiles, 7r was selected for the in-vivo pharmacological evaluation. Oral triglyceride tolerance test highlighted effect of 7r on the inhibition of triglyceride absorption. A four-week treatment of 7r in the HFD feed mice provided information regarding its anti-obesity effect with respect to parameters such as body weight, triglycerides, total cholesterol and high-density lipids. Quantification of the faecal triglyceride contents inveterates the potential role of 7r in the PL inhibition. Overall, the synthesized analogue 7r exerted an anti-obesity effect comparable to orlistat. All these results demonstrated the potential role of the newly synthesised indole-thiazolidinedione hybrid analogues in PL inhibition and may be studied further to find potential drug candidates for treating obesity. Communicated by Ramaswamy H. Sarma

Efficient screening of pancreatic lipase inhibitors from Rheum palmatum by affinity ultrafiltration-high-performance liquid chromatography combined with high-resolution inhibition profiling.

Pancreatic lipase is one of the most important key targets in the treatment of obesity. Inhibition of pancreatic lipase can effectively reduce lipid absorption and treat obesity and other related metabolic disorders. The goal of this study is the efficient screening of pancreatic lipase inhibitors in the root and rhizome of Rheum palmatum using affinity ultrafiltration-high-performance liquid chromatography (AUF-HPLC) combined with high-resolution inhibition profiling (HRIP). Potential pancreatic lipase ligands and pancreatic lipase inhibitors in ethyl acetate fraction of R. palmatum were screened using AUF-HPLC and HRIP, respectively. All screened compounds were identified by HPLC- quadrupole time-of-flight (Q-TOF)/MS. Eight compounds were screened out by both AUF-HPLC and HRIP, and six compounds were screened out by either AUF-HPLC or HRIP alone. The pancreatic lipase inhibitory activities of all screened compounds were verified by enzyme inhibition assay and molecular docking. Five new potent pancreatic lipase inhibitors were discovered, namely procyanidin B5 3,3'-di-O-gallate (IC50 = 0.06 ± 0.01 μM), 1,6-di-O-galloyl-2-O-cinnamoyl-β-D-glucoside (IC50 = 12.83 ± 0.67 μM), 1-O-(1,3,5-trihydroxy)phenyl-2-O-galloyl-6-O-cinnamoyl-β-D-glucoside (IC50 = 17.84 ± 1.33 μM), 1,2-di-O-galloyl-6-O-cinnamoyl-β-D-glucoside (IC50 = 18.39 ± 1.52 μM), and 4-(4'-hydroxyphenyl)-2-butanone-4'-O-β-D-(2"-O-galloyl-6"-O-cinnamoyl)-glucoside (IC50 = 2.91 ± 0.40 μM). It was found that procyanidin B5 3,3'-di-O-gallate showed higher pancreatic lipase inhibitory activity than the positive control orlistat (IC50 = 0.12 ± 0.02 μM). The combination of affinity ultrafiltration-high-performance liquid chromatography (AUF-HPLC) and high-resolution inhibition profiling (HRIP) could reduce the risk of false-negative screening and missed screening and could achieve more efficient screening of bioactive compounds in complex natural products.

Design, synthesis, biological evaluation and molecular docking of alkoxyaurones as potent pancreatic lipase inhibitors

Aurones are a minor subgroup of flavonoids. Unlike other subgroups such as chalcones, flavones, and isoflavones, aurones have not been extensively explored as pancreatic lipase inhibitors. In this work, we studied the pancreatic lipase inhibitory potency of synthetic aurone derivatives. Thirty-six compounds belonging to four series (4,6-dihydroxyaurone, 6-hydroxyaurone, 4,6-dialkoxyaurone, and 6-alkoxyaurone) were designed and synthesized. Their in vitro inhibitory activities were determined by spectrophotometric assay in comparison with quercetin and orlistat. Alkoxyaurone derivatives with long-chain (6–10 carbons) alkoxy substituents showed greater potency. Of them, 4,6-dialkoxyaurone 8 displayed the highest activity against pancreatic lipase (IC50 of 1.945 ± 0.520 µM) relative to quercetin (IC50 of 86.98 ± 3.859 µM) and orlistat (IC50 of 0.0334 ± 0.0015 µM). Fluorescence quenching measurement confirmed the affinity of alkoxyaurone derivatives to pancreatic lipase. Kinetic study showed that 8 inhibited lipase through a competitive mechanism (Ki of 1.288 ± 0.282 µM). Molecular docking results clarified the role of long-chain substituents on ring A in interacting with the hydrophobic pockets and pushing the inhibitor molecule closer to the catalytic triad. The findings in this study may contribute to the development of better pancreatic lipase inhibitors with aurone structure.

Design, Synthesis, Molecular Modelling and in Vitro Evaluation of Indolyl Ketohydrazide-Hydrazone Analogs as Potential Pancreatic Lipase Inhibitors.

Inhibition of Pancreatic lipase (PL) is considered to be a promising target for the management of obesity, owing to its crucial role in the digestion of dietary triglycerides. A series of 31 indolyl ketohydrazide-hydrazone analogs (5 aa-cm) were designed, synthesized and evaluated for their PL inhibitory potential. The analogs were designed using molecular modelling studies. The designed analogs were then synthesized by condensation of indolyl oxoacetohydrazide with various substituted benzaldehydes. All the synthesized analogs showed PL inhibitory activity in the range of 4.13-48.35 μM, as compared with orlistat (0.86±0.09 μM). The most potent analog 5 bi (IC50 =4.13±0.95 μM) was found to show a competitive type of inhibition with Ki value of 0.725 μM. Additionally, the molecular docking study proved the binding of analog 5 bi at the active site of PL (PDB ID: 1LPB) with MolDock score of -141.279 kcal/mol. It also exhibited various interactions with the key amino acids namely Phe77, Phe215, Tyr114, Ser152, Arg256, His263, etc. Furthermore, the protein-ligand complex of analog 5 bi was found to be stable in molecular dynamics simulation for 100 ns with RMSD of less than 3.2 and 4 Å for the protein and ligand, respectively. The current work hereby provides a basis for the potential role of indolyl ketohydrazide-hydrazone analogs in PL inhibition and further optimization could result in the generation of new leads as anti-obesity agents.

Synthesis of amide warhead containing coumarin derivatives as potential pancreatic lipase inhibitors: in silico and in vitro evaluation for obesity treatment

Synthesis of amide warhead containing coumarin derivatives as potential pancreatic lipase inhibitors: in silico and in vitro evaluation for obesity treatment

Metal Chelators as Anticancer Approach: Part I; Novel 7-Anisidine Derivatives with Multidentate at 7-8 Carbons of Fluoroquinolone Scaffold as Potential Chelator Anticancer and Antilipolytic Candidates

Background: Cancer is one of the greatest troubling maladies currently. It is believed that it is the second reason for death following cardiovascular maladies. Owing to the multiplicity of its types, stages and genetic basis, there is no existing drug to cure all types of cancer. Resistance to present drugs and severe adverse effects are other challenges in the struggle against cancer. In such pursuit, fluoroquinolones (FQs) have the potential as antiproliferative compounds due to safety, low cost, and absence of resistance.&#x0D; Aims: In this study, we aim to synthesize biologically active compounds that have dual anticancer and anti-lipase potential. Sixteen compounds were prepared, fully characterized, and studied through identification of IC50 values against the highly susceptible cancer cell lines.&#x0D; Methods: In this work we are concerned with synthesizing biologically active compounds that belong to fluoroquinolones (FQs) with dual anti-colorectal cancer and anti-lipase activity, owing to association between cancer and obesity, conduct titration and docking experiments to validate our hypothesis.&#x0D; Results: In vitro findings indicated that these compounds demonstrated promising anticancer activity against tested cell lines in micromolar range with a potency comparable to cisplatin. Compound 11 exhibited approximately doubled potency compared to cisplatin against SW620 colorectal cancer cell line with IC50 3.2 μM which proposes FQs as potent antiproliferative agents. The synthesized Fluoroquinolone (FQ) compounds were further screened for their in vitro anti-lipase potential. The findings demonstrated that all the screened compounds have demonstrated remarkable anti-lipase activity, as compared to control molecule orlistat. Compound 9 exhibited comparable activity to orlistat against pancreatic lipase with IC50 0.4 μM which proposes FQs as potent pancreatic lipase inhibitors.&#x0D; Conclusions: The anticancer potential of these derivatives is referred to their ability to inhibit Topo II which indicates that chelation is the mechanism of inhibition of Topo II emphasized with titration and docking experiments.

Chromone-3-acrylic acid ester analogues: Design, synthesis and biological evaluation as potential pancreatic lipase inhibitors

A novel series of 21 chromone-3-acrylic acid ester analogues (5aa-5cm) were designed, synthesized and evaluated for PL inhibitory activity. The molecular docking study indicate that all the designed chromone analogues have the good binding ability (MolDock score: -115.86 to -160.07 kcal/mol) in the active site of PL enzyme (PDB ID: 1LPB), showing interactions with essential amino acid residues (Phe77, Tyr114, Ser152, Phe215, Arg256). Also, all the analogues were checked for in silico drug likeness property and all were found to have drug like properties, obeying Lipinski rule of 5, with no PAINS alerts. Analogue 5am, with the best docking score, was stable in molecular dynamics simulation for 100 ns (maximum RMSD of 6.4 Å), showing crucial amino acid interactions for more than 60% of the simulation time. The structure of the synthesized analogues were then confirmed by NMR, HRMS and IR spectroscopy. Among the synthesized analogues, 5am and 5ad exhibited potent PL inhibition with IC50 of 5.16 ± 0.287 & 5.82 ± 0.933 µM, respectively, as compared with orlistat (IC50 = 0.86 ± 0.09 µM). The inhibition kinetics and in silico studies confirmed competitive type of inhibition of analogue 5am. The current work highlights the importance of chromone analogues as potential PL inhibitors. Further, the lead optimization may lead to much more potential PL inhibitors.

Phytochemical Profiling and Pancreatic Lipase Inhibitory Activity of &lt;i&gt;Flacourtia inermis&lt;/i&gt; Roxb. Fruits

Objectives: The present research work was carried out to explore the potential use Flacourtia inermis [FI] fruits for the prevention and treatment of obesity through pancreatic lipase inhibition in vitro. The study also aimed to investigate the chemical profiling of ethanol extract of FI using High-Performance Thin Layer Chromatography (HPTLC), High-Resolution Liquid Chromatography (HR-LC/MS), and Nuclear Magnetic Resonance Spectroscopy (NMR). Materials and Methods: Dried fruits of Flacourtia inermis were pulverised and subsequently extracted using various solvents in sequential steps of increasing polarity, such as hexane, ether, chloroform, ethyl acetate, ethanol, and water. After phytochemical analysis by preliminary chemical testing various extracts were evaluated for their ability to inhibit pancreatic lipase, and the ethanol extract was found to have an IC&lt;sub&gt;50&lt;/sub&gt; close to that of reference drug orlistat. The most potent ethanol extract was analysed by HPTLC and separated through column chromatography, and further analysis was performed by HR-LC/MS and 1H-NMR techniques. Results: The presence of various phytoconstituents in this plant was detected using different types of analytical techniques. PL lipase inhibitory activity was observed in extracts in a dose dependent manner. Performing PL inhibition assay, it was found that the ethanol fruit extracts have lipase inhibitory activity with an IC&lt;sub&gt;50&lt;/sub&gt; value of 377.15 μg/ml. HPTLC finger printing of the ethanol extract showed the presence of various bioactice compounds. HR-LC/MS study of the most active ethanol extract indicated the presence of different phytochemicals, such as phenolics and flavonoids. Column chromatographic separation of ethanol fruit extract of FI followed by structural elucidation using various spectral studies demonstrated the presence of two compounds namely myricetin and quinic acid. Conclusion: The study suggests that the edible fruits of Flacourtia inermis have the potential to inhibit pancreatic lipase enzyme and therefore, may be recommended for the management of obesity. Additionally, our research sheds light on the phytochemistry of flacourtia species and may lead to the development of novel chemical entities as potential pancreatic lipase inhibitors.

A computational study to probe the binding aspects of potent polyphenolic inhibitors of pancreatic lipase

Pancreatic lipase (PL) is a keen target for anti-obesity therapy that reduces dietary fat absorption. Here, we investigated the binding patterns of 220 PL inhibitors having experimental IC50 values, using molecular docking and binding energy calculations. Screening of these compounds illustrated most of them bound at the catalytic site (S1-S2 channel) and a few compounds are at the non-catalytic site (S2-S3 channel/S1-S3 channel) of PL. This binding pattern could be due to structural uniqueness or bias in conformational search. A strong correlation of pIC50 values with SP/XP docking scores, binding energies (ΔGMMGBSA) assured the binding poses are more true positives. Further, understanding of each class and subclasses of polyphenols indicated tannins preferred non-catalytic site wherein binding energies are underestimated due to huge desolvation energy. In contrast, most of the flavonoids and furan-flavonoids have good binding energies due to strong interactions with catalytic residues. While scoring functions limited the understanding of sub-classes of flavonoids. Hence, focused on 55 potent PL inhibitors of IC50 < 5 µM for better in vivo efficacy. The prediction of bioactivity, drug-likeness properties, led to 14 bioactive compounds. The low root mean square deviation (0.1-0.2 nm) of these potent flavonoids and non-flavonoid/non-polyphenols PL-inhibitor complexes during 100 ns molecular dynamics runs (MD) as well as binding energies obtained from both MD and well-tempered metadynamics, support strong binding to catalytic site. Based on the bioactivity, ADMET properties, and binding affinity data of MD and wt-metaD of potent PL-inhibitors suggests Epiafzelechin 3-O-gallate, Sanggenon C, and Sanggenofuran A shall be promising inhibitors at in vivo conditions. Communicated by Ramaswamy H. Sarma

Novel Plant-Protein (Quinoa) Derived Bioactive Peptides with Potential Anti-Hypercholesterolemic Activities: Identification, Characterization and Molecular Docking of Bioactive Peptides

Hypercholesterolemia remains a serious global public health concern. Previously, synthetic anti-hypercholesterolemic drugs were used for ameliorating this condition; however, long-term usage presented several side-effects. In this regard, natural products as an adjunct therapy has emerged in recent times. This study aimed to produce novel bioactive peptides with anti-hypercholesterolemic activity (cholesterol esterase (CEase) and pancreatic lipase (PL)) from quinoa protein hydrolysates (QPHs) using three enzymatic hydrolysis methods (chymotrypsin, protease and bromelain) at 2-h hydrolysis intervals (2, 4, and 6 h). Chymotrypsin-generated hydrolysates showed higher CEase (IC50: 0.51 mg/mL at 2 h) and PL (IC50: 0.78 mg/mL at 6 h) inhibitory potential in comparison to other derived hydrolysates and intact quinoa proteins. Peptide profiling by LC-MS QTOF and in silico interaction with target enzymes showed that only four derived bioactive peptides from QPHs could bind in the active site of CEase, whereas twelve peptides could bind in the active site of PL. Peptides QHPHGLGALCAAPPST, HVQGHPALPGVPAHW, and ASNLDNPSPEGTVM were identified to be potential CEase inhibitors, and FSAGGLP, QHPHGLGALCAAPPST, KIVLDSDDPLFGGF, MFVPVPH, and HVQGHPALPGVPAHW were identified as potential PL inhibitors on the basis of the maximum number of reactive residues in these bioactive peptides. In conclusion, QPHs can be considered as an alternative therapy for the treatment of hypercholesterolemia.

3D-QSAR, design, docking and in silico ADME studies of indole-glyoxylamides and indolyl oxoacetamides as potential pancreatic lipase inhibitors

The versatility of indole heterocyclic led to the understanding of their structural requirements to develop new potential derivatives. The indole derivatives estimated to be active against pancreatic lipase have been chosen to develop 3D-QSAR field and atom-based models, validated using the Schrodinger suite. Designing of new agents through QSAR based predictions and performing docking on these compounds helped in defining the binding pattern and pharmacophoric features like π–π stacking interactions, hydrogen bonding, and π-cation interactions with the amino acid residues. The protein-ligand complex displayed good binding energies. In silico ADMET properties have been generated using the Quick-prop module of the Schrodinger suite. The 3D-QSAR model is found to be statistically significant and evaluated using various parameters like R2, R2CV, stability, F-value, P-value, RMSE, Q2, and Pearson-r by PLS factor of 4. The field fractions and contour maps along with their visualizations have helped in inferring the essential nature and type of substituent that should be incorporated for a compound to display potent pancreatic lipase inhibitory activity. These deductions and evaluations of the synthesized compounds through the generation of models could be further utilized for designing new molecules rationally.

Discovery of A Novel Synthetic Thiazole-benzimidazole Conjugate that Acts as a Potent Pancreatic Lipase Inhibitor using in silico and in vitro Approaches

Abstract: Aim/ Background: Pancreatic lipase (PL) inhibition has been suggested to be an effective method for obesity management. In this study, 10 novel thiazole-benzimidazole conjugates were designed. Materials and Methods: Conjugates were initially screened via in silico experiments, such as ADMET analysis and molecular docking, to identify the most promising PL inhibitors. Results: Results revealed that compounds 3, 6 and 8 had the most optimum druglikeness properties, and the highest binding affinity to PL, with binding energies of -7.7, -7.5 and -8.1 kcal/mol, respectively. Therefore, these promising derivatives were then synthesized and subjected to an in PL inhibition assay to validate the results of the in silico experiments. The synthetic compounds were fully characterized via FTIR, 1H-NMR, 13C-NMR and LCMS. Results of the enzymatic assay revealed that 3, 6 and 8 inhibited PL potently with high inhibition rates of greater than 80% at the highest tested dose, and demonstrated IC50 values of 68.53, 54.97 and 50.09 μM, respectively. Compound 8 was the most active derivative and displayed comparable activity to orlistat which possessed an IC50 value of 39.18μM. Conclusion: Therefore, we report the discovery of compound 8 as a highly potent PL inhibitor that could act as a lead compound to develop novel anti-obesity agents. Keywords: Pancreatic lipase, Inhibition, Thiazole-benzimidazole, in silico, in vitro, Enzyme assay.

Molecular modelling, synthesis and in vitro evaluation of quinazolinone hybrid analogues as potential pancreatic lipase inhibitors

Obesity is a multifactorial metabolic disorder, growing in an alarming rate across the world. Amongst the numerous targets explored for obesity management, inhibition of pancreatic lipase (PL) is considered as one of the promising approaches. Orlistat is the only PL inhibitory drug approved for long term treatment of obesity. However, it is reported to possess hepatotoxicity and nephrotoxicity. Thus, novel drug candidates that act through PL inhibition are considered the hour’s need. Based on this aim, a series of quinazolinone hybrid analogues have been synthesized, characterized and evaluated for their PL inhibitory potential. The physicochemical properties and toxicity parameters suggested that these parameters are in an acceptable range for the screened analogues. Amongst the synthesised analogues, QH-25 exerted potential PL inhibition (IC50 = 16.99 ± 0.54 µM). Further, enzyme inhibition studies suggested a reversible competitive inhibition. Molecular docking of these analogues was in line with in vitro results, wherein the obtained MolDock scores exhibited a significant correlation with their inhibitory activity (Pearson’s r = 0.6629). To further confirm the stability of the QH-25-PL complex in a dynamic environment, a molecular dynamics study (100 ns) was carried out and the results suggested that this complex is stable at dynamic conditions. Overall, these results shed light on the quinazolinone hybrids as potential PL inhibitors. Further structural modification may result in the development of potent anti-obesity agents which acts through PL inhibition. Communicated by Ramaswamy H. Sarma

Design and Synthesis of Echitamine-inspired Hybrid Analogues Containing Thiazolidinediones as Potential Pancreatic Lipase Inhibitors

Background: Obesity is a multifactorial metabolic disease characterised by excessive accumulation of triglycerides. The prevalence and morbidity rates associated with obesity are increasing tremendously, posing a significant risk to society. Pancreatic lipase (PL) is a key enzyme responsible for the digestion of dietary triglycerides; hence its inhibition is considered an attractive target in obesity. Methods: In this present work, a new series of echitamine-inspired indole-based thiazolidinedione hybrid analogues were designed, synthesized, and evaluated for their in vitro PL inhibitory potential. The nature of inhibition has been identified by enzyme kinetic analysis, whereas in silico molecular modelling tools (molecular docking and dynamic studies) were used for the identification of the mode of action at the catalytic site of PL (PDB ID: 1LPB). Fluorescence quenching was used for the identification of the interaction between the potent analogues with PL. Results: The condensation reaction of substituted indole derivatives with TZD in the presence of aqueous KOH resulted in the formation of the titled analogues. Analogues 7k and 7p displayed a potential PL inhibitory activity (IC50 = 11.36 and 11.87 μM, respectively). A competitive mode of PL inhibition was revealed in the enzyme kinetic analysis. A static quenching mechanism was exhibited by the screened agents on PL. The obtained MolDock scores were aligned with the in vitro PL inhibitory activity (Pearson’s r - 0.7575, p &lt; 0.05). Moreover, the PL-ligand complexes were stable in the dynamic conditions. Conclusion: Analogue 7k exerted the potential activity, and further studies might result in novel lead molecules.

Characterization of the synergistic inhibitory effect of cyanidin-3-O-glucoside and catechin on pancreatic lipase

This study aimed to identify novel pancreatic lipase (PL) inhibitors using affinity ultrafiltration combined with spectroscopy and molecular docking. Cyanidin-3-O-glucoside (C3G; IC50: 0.268 mg/mL) and catechin (IC50: 0.280 mg/mL) were shown to be potent PL inhibitors extracted from black rice and adzuki bean coat extracts. Isobologram analysis revealed that the combined use of C3G and catechin at a ratio of 2:3 had a remarkable synergistic effect (IC50 of the mixture: 0.201 mg/mL). The inhibitory mechanism of C3G-catechin mixture was of mixed type. The C3G-catechin mixture had a great impact on PL secondary structures. Molecular docking analysis further demonstrated that these polyphenols formed hydrophobic interactions and hydrogen bonds with amino acid residues in the binding pocket of PL. Collectively, C3G and catechin were shown to inhibit PL in a synergistic manner and can be potentially used for the development of food supplements for obesity prevention.

Design, in silico study, synthesis and in vitro evaluation of some N5-(1H-pyrazol-3-yl)-3H-benzo[d]imidazole-2,5-diamine derivatives as potential pancreatic lipase inhibitors for anti-obesity activity.

The aim of the study is to design N5-(1H-pyrazol-3-yl)-3H-benzo[d]imidazole-2,5-diamine derivatives and evaluate its anti-obesity activity. A few pyrazole-fused benzimidazole derivatives were designed as potential Pancreatic Lipase (PL) inhibitors. The designed N5-(1H-pyrazol-3-yl)-3H-benzo[d]imidazole-2,5-diamine derivatives have been screened using the Lipinski rule of five, ADMET analysis, acute toxicity prediction, and molecular docking. Later on, the derivatives which possess the most drug-likeness properties and displayed the most potent inhibition of the enzyme in molecular docking were synthesized. Then, in vitro enzyme assay was performed. Orlistat used as the standard exhibited 91±1.68% inhibition of the enzyme, displayed binding affinity (BA) of only -4.5 kcal/mol with Pancreatic Lipase (PL), and made only one salt bridge attractive charge and carbon-hydrogen bond with ASP79 and TRP252, respectively. Compound 9 displayed the most potent activity (93±1.12% inhibition of P.L. and -9.5 kcal/mol BA). It has formed five conventional H- bonds with GLU253, ILE78, ASP79, PHE258, and one Pi-donor H- bond with ILE78. From the present investigation, we hereby reported (E)-N2-((naphthalene-1-yl)methylene)-N5-(1H-pyrazol-3-yl)-3H-benzo[d]imidazole-2,5-diamine as most potent PL inhibitor for the treatment of obesity, which can be further optimized by undergoing more studies using in vivo and in vitro models. (E)-N2-((naphthalene-1-yl)methylene)-N5-(1H-pyrazol-3-yl)-3H-benzo[d]imidazole-2,5-diamine as most potent PL inhibitor for the treatment of obesity which can be further optimized better using more in vivo and in vitro models. PL plays a critical role in digesting dietary fat. Therefore, PL inhibitors are verified as a potential therapy for treating obesity.

Natural mimetic 4-benzyloxychalcones as potent pancreatic lipase inhibitors: Virtual screening, synthesis and biological evaluation

Pancreatic lipase is a well-known target for obesity drug development. The inhibition of this enzyme mitigates the digestion and absorption of dietary fat. Despite some inconvenient side effects, orlistat is currently the only medication with FDA approval that works by inhibition of pancreatic lipase. Several natural flavonoids, including chalcones, have been reported to possess promising lipase inhibitory activity. In this paper, we describe the evaluation of the lipase inhibitory activity of our in-house natural mimetic chalcone library via virtual screening, followed by the synthesis and biological evaluation of the hits. Compound C82 showed low-micromolar activity against pancreatic lipase in vitro (IC 50 = 1.01 ± 0.86 µM). The interaction of C82 and lipase was additionally confirmed by a fluorescence quenching study. • Natural mimetic 4-benzyloxychalcone derivatives were identified as potential pancreatic lipase by computational methods. • Six 4-benzyloxychalcone derivatives were synthesized and evaluated for in vitro pancreatic lipase inhibitory activity. • Compound C82 showed low-micromolar activity • The interaction of compound C82 and pancreatic lipase was confirmed by a fluorescence quenching experiment.