Assessing structural insights into in-house arylsulfonyl L-(+) glutamine MMP-2 inhibitors as promising anticancer agents through structure-based computational modelling approaches

Design and synthesis of new 1,4-naphthoquinones appended sulfenylated thiazoles as cyclooxygenase II inhibitors: Exploring the utility in the development of anticancer agents

Clinical evaluations revealed the direct role of chronic inflammation in cancer progression. The cyclooxygenase (COX) pathway is particularly important among the various pathways involved in inflammation. There are two COX isoforms: COX-1 and COX-2. The importance of drug discovery lies in selectively inhibiting COX-2, an enzyme expressed during inflammation, unlike COX-1, which is constitutively active. The inhibition of COX-1 is correlated further with gastric ulcers. However, recently approved COX-2 inhibitors have intricate cardiotoxicity, thus creating an utmost need for new COX-2 inhibitors. Considering this, in our present research, we rationally designed and synthesized a series (4a-4q) of 1,4-naphthoquinones appended sulfenylated thiazoles using molecular hybridization approach under metal-free conditions. These synthetics were explored for their anticancer potential against three cell lines, and the hits portraying anticancer effects were further tested against COX isoforms. Among all, compounds 4d and 4f were found to be potent anticancer leads, exhibiting selective inhibition of COX-2 and, concomitantly, the lipoxygenase (LOX) pathway, both of which share the same substrate, arachidonic acid. Both compounds were found to reduce oxidative stress and induce cancer cell death via apoptosis pathway. The experimental outcome was further corroborated using in silico techniques, including density field theory (DFT), Molecular docking, and dynamics.

Enhancing thermal stability of pectinase using thermal titration molecular dynamics and density functional theory approach

Pectinase, an enzyme primarily produced from Aspergillus niger, is essential in various industrial applications. However, the enzyme's functionality at high temperatures is challenging, restricting its effectiveness and potential uses. Therefore, the present study investigated the potential of peptide binding to enhance the thermal stability of pectinase. Thermal titration molecular dynamics (MD) simulations were performed at 300, 320, 340 and 360 K to identify regions susceptible to thermal fluctuations. Based on these results, 235,200 peptide sequences were screened to target the detected unstable regions. Machine learning models predicted the peptide activity and 12 promising peptide-protein complexes were identified using docking. Binding free energy calculations showed pep-10 (-19.4 kcal/mol), pep-8 (-17.97 kcal/mol), pep-12 (-15.25 kcal/mol) and pep-6 (-9.86 kcal/mol) as the most promising candidates to improve the thermal stability. Density functional theory calculations showed that pep-12 had the lowest energy of -2365. MD simulations at 360 K for 100 ns demonstrated that pep-12 maintained the most stable conformation with root mean square deviation (0.2-0.25 nm) compared to other peptides. Quantum mechanics/molecular mechanics hybrid approach to examine the mechanism of the pep-12 complex with Pectinase. The outcomes of this study suggested that pep-12 is the most potential candidate for enhancing pectinase thermal stability.

Coevolution-based protein engineering of alcohol dehydrogenase at distal sites enables enzymatic compatibility with substrate diversity and stereoselectivity

Chiral alcohols with various substituents and functional groups are attractive synthesizers in many fields. Biocatalysts have attracted great interest for their use in " sustainable chemistry". However, substrate specificity of enzymes limits their widespread use as "generalists" in biocatalysis. In addition, engineering enzymes for simultaneously improving catalytic efficiency and stereoselectivity for structurally diverse substrates is a contemporary challenge. Inspired by naturally occurring coevolution of residues dedicated to a particular function and clustered together in space, we applied coevolution-based engineering to the alcohol dehydrogenase CpRCR from Candida parapsilosis to identify distal sites which can synergistically improve the catalytic properties of diverse substrates. Five variants were developed by clustering the coupling strength and structure of coevolutionary sites which showed improved (up to 28-fold) catalytic efficiency with high stereoselectivity toward 16 structurally diverse substrates (aryl ketones, heterocyclic ketones and β-ketoesters). In particular, for substrate 2-acetylpyridine, the specific activity of K191L/D216H is 12-fold higher than the previously reported highest activity of alcohol dehydrogenase. Theses distal mutations do not directly modify the active center but rather modulate catalytic capacity in various allosteric ways favoring substrate diversity. This study provides a broadly applicable strategy for protein engineering and expanded the applications of biocatalyst on value-added chemicals.

The coevolutionary landscape of drug resistance in epidermal growth factor receptor: A cancer perspective

Epidermal growth factor receptor (EGFR), the first receptor tyrosine kinase, plays a critical role in neoplastic metastasis, angiogenesis, tumor invasion, and apoptosis, making it a prime target for treating non-small cell lung cancer (NSCLC). Although tyrosine kinase inhibitors (TKIs) have shown high efficacy and promise for cancer patients, resistance to these drugs often develops within a year due to alterations. The present study investigates the compensatory alterations in EGFR to understand the evolutionary process behind drug resistance. Our findings reveal that coevolutionary alterations expand the drug-binding pocket; leading to reduced drug efficacy and suggested that such changes significantly influence the structural adaptation of the EGFR against these drugs. Analysis such as root mean square deviation (RMSD), root mean square fluctuation (RMSF), solvent accessible surface area (SASA), principal component analysis (PCA), and free energy landscape (FEL) demonstrated that structures of wild EGFR docked with gefitinib are more stable which suggests its susceptibility towards drug than coevolution dependent double mutant. The findings were supported by MM-GBSA binding affinity analysis. The insights from this study highlighted the evolution-induced structural changes which contributes to drug resistance in EGFR and may certainly aid in designing more effective drugs.

Ligand-based cheminformatics and free energy-inspired molecular simulations for prioritizing and optimizing G-protein coupled receptor kinase-6 (GRK6) inhibitors in multiple myeloma treatment

Multiple myeloma (MM) is the second most frequently diagnosed hematological malignancy, presenting limited treatment options with no curative potential and significant drug resistance. Recent studies involving genetic knockdown established the crucial role of GRK6 in upholding the viability of MM cells, emphasizing the need to identify potential inhibitors. Computational exploration of GRK6 inhibitors has not been attempted previously. Herein, the present study reports a multilayered lead prioritization and optimization framework using chemometrics and molecular simulations. 2D QSAR studies revealed that hydrogen bonding and polar interactions enhanced GRK6 inhibitory activity, while increased electron accessibility posed a risk of off-target effects. The pharmacophore hypothesis (DDHRRR_1) featured two hydrogen bond donors, one hydrophobic region, and three aromatic rings, laying the foundation for the 3D QSAR models. Hydrophobic groups, such as pyridine and pyrazole, were shown to enhance inhibition, while smaller groups, like ethyl and hydroxyl, reduced activity. 12,557 DrugBank compounds were screened using the developed chemometric models and molecular docking in tandem, which led to the identification of 7 potential parent leads for subsequent QSAR-guided structural optimizations. 350 lead analogs were generated and the top 4 were further analyzed using molecular docking, ADMET, molecular dynamics, and metadynamics analysis based on Principal Component Analysis (PCA), Probability Density Function (PDF), and Free Energy Landscapes (FEL). Upon cumulative retrospection, we propose a novel analog of DB07168 (DB07168-A13) (docking score: -11.2 kcal/mol, MM-GBSA binding energy: -55.2 kcal/mol) as the most promising GRK6 inhibitor, warranting further in vitro validation, for addressing prospective therapeutic intervention in MM.

Design and evaluation of novel triazole derivatives as potential anti-gout inhibitors: a comprehensive molecular modeling study

Introduction

Gout is the most common inflammatory arthritis, characterized by hyperuricemia, tophus formation, joint disease, and kidney stones. Uric acid, the final byproduct of purine catabolism, is eliminated via the kidneys and digestive system. Xanthine oxidase (XO) catalyzes the conversion of hypoxanthine and xanthine into uric acid, making XO inhibitors crucial for treating hyperuricemia and gout. Currently, three XO inhibitors are clinically used, showing significant efficacy. A molecular modeling study on triazole derivatives aims to identify novel XO inhibitors using 3D-QSAR, molecular docking, MD simulations, ADMET analysis, and DFT calculations. These computational approaches facilitate drug discovery while reducing research costs.

Methods

Our work focuses on a series of synthesized anti-xanthine oxidase inhibitors, aiming to develop new inhibitors. A computational study was carried out to identify the xanthine oxidase inhibitory structural features of a series of triazole inhibitors using computational method.

Results

A model based on CoMFA and CoMSIA/SEA has been built to predict new triazole derivatives.

Discussion

The optimal model established from CoMFA and CoMSIA/SEA was successfully evaluated for its predictive capability. Visualization of the contour maps of both models showed that modifying the substituents plays a key role in enhancing the biological activity of anti-gout inhibitors. Molecular docking results for complexes N°8-3NVY and N°22-3NVY showed scores of -7.22 kcal/mol and -8.36 kcal/mol, respectively, indicating substantial affinity for the enzyme. Complex N°8-3NVY forms two hydrogen bonds with SER 69 and ASN 71, three alkyl bonds with ALA 70, LEU 74, and ALA 75, and one Pi-Pi T-shaped bond with PHE 68. Complex N°22-3NVY forms three hydrogen bonds with HIS 99, ARG 29, and ILE 91, and one halogen bond with LEU 128 at 3.60 Å. A MD study revealed that the N°22-3NVY complex remained highly stable throughout the simulation. Therefore, we proposed six new molecules, their anti-gout inhibitory activities were predicted using two models, and they were evaluated for Lipinski's rule, and ADMET properties. The results show that both Pred 4 and Pred 5 have better pharmacokinetic properties than the height potent molecule in the studied series, making these two compounds valuable candidates for new anti-gout drugs. Subsequently, using DFT study to evaluate the chemical reactivity properties of these two proposed compounds, the energy gap results revealed that both molecules exhibit moderate chemical stability and reactivity.

Elucidating the therapeutic potential of indazole derivative bindarit against K-ras receptor: An in-silico analysis using molecular dynamics exploration

Ras gene is frequently mutated in cancer. Among different subtypes of Ras gene, K-Ras mutation occurs in nearly 30 % of human cancers. K-Ras mutation, specifically K-Ras (G12D) mutation is prevalent in cancers like lung, colon and pancreatic cancer. During cancer occurrence, mutant Ras remain in activated form (GTP bound state) for cancer cell proliferation. In the quest for a potential K-Ras inhibitor, nitrogen-containing indazole derivatives can show promise as inhibitors, as they have numerous therapeutic properties like anti-inflammatory, anti-viral and anti-tumor. Furthermore, among various indazole derivatives, "Bindarit" is an important therapeutic compound which could have potential inhibitory action against K-Ras due to its structural resemblance with reference compound "Benzimidazole". So, the current study is an attempt to find out the inhibitory effect of Bindarit against K-Ras activation by binding to a pocket which is adjacent to the switch I/II regions of the K-Ras receptor. AutoDock tool was used to investigate the binding affinity of protein ligand interaction and GROMACS package was utilised to assess their interactions in a dynamic setting. Bindarit shows better binding affinity than reference with binding energy of -7.3 kcal/mol. Upon ligand binding conformational changes take place, which could lead to the loss of GTPase activity. Consequently, further downstream signalling of the K-Ras pathway would be blocked and this could lead to the inhibition of K-Ras dependent cancer cell proliferation. However, further validation of present study can be done through experimental assay such as cytotoxic and protein expression analysis.

Identification and mechanistic study of piceatannol as a natural xanthine oxidase inhibitor

Natural Xanthine oxidase (XOD) inhibitors represent promising therapeutic agents for hyperuricemia (HUA) treatment due to their potent efficacy and favorable safety profiles. This study involved the construction of a comprehensive database of 315 XOD inhibitors and development of 28 machine learning-based QSAR models. The ChemoPy light gradient boosting machine model exhibited the best performance (AUC = 0.9371 and MCC = 0.7423). This model identified three potential XOD inhibitors from the FooDB database: daphnetin, 7-hydroxycoumarin, and piceatannol. Molecular docking and dynamics simulations revealed favorable interactions, with piceatannol showing a remarkable stability through hydrogen bonding and hydrophobic interactions. ADME predictions suggested that all three compounds possess desirable drug-like properties and safety characteristics. Subsequent in vitro enzyme inhibition assays validated computational predictions, with piceatannol exhibiting the strongest inhibitory activity (IC50 = 8.80 ± 0.05 μM). Multispectroscopic analyses revealed that piceatannol-XOD binding was predominantly mediated by hydrogen bonding and van der Waals forces, which induced conformational changes characterized by decreased α-helical content and increased proportions of β-sheets, β-turns, and random coils. This study presents an efficient strategy for the identification of natural XOD inhibitors, elucidates the molecular mechanism of piceatannol-mediated XOD inhibition, and establishes a foundation for its therapeutic application in HUA treatment.

CADD-based discovery of novel oligomeric modulators of PKM2 with antitumor activity in aggressive human glioblastoma models

Pyruvate kinase isoform M2 (PKM2) is a multifunctional enzyme capable of transitioning between monomeric, dimeric, and tetrameric states, with its oligomeric equilibrium playing a pivotal role in tumour progression and survival. The unique exon ten at the dimer-dimer interface represents an attractive target for isoform-specific modulation, offering opportunities for disrupting this equilibrium and altering tumour cell dynamics. This study identifies a novel druggable pocket at the PKM2 dimer interface through conformational analysis. This pocket was exploited in a virtual screening of a large small-molecule library, identifying two promising candidates, C599 and C998. Both compounds exhibited dose-dependent antiproliferative effects in glioblastoma cell lines and induced apoptosis, as evidenced by caspase 3/7 activation. These effects were directly linked to their inhibition of PKM2 enzymatic activity, validating the proposed mechanism of action in their rational design. ADMET studies further highlighted their strong potential as lead PKM2 inhibitors for GBM treatment. Molecular dynamics (MD) simulations and post-MD analyses, including Dynamic Cross-Correlation Maps (DCCM), Probability Density Function (PDF), and Free Energy Landscape (FEL), confirmed the stability of the protein-ligand interactions and highlighted critical residues at the dimer-dimer interface. The Steered MD simulations demonstrated the high affinity of the compounds for PKM2, as evidenced by the requirement of high rupture forces to induce an unbinding event. These results highlight the potential of the compounds as oligomeric modulators of PKM2. These findings position C599 and C998 as promising lead compounds for antitumor applications. Future studies will focus on optimising these candidates and assessing their efficacy in vivo glioblastoma models, reassuring the thoroughness of our research and the potential for further advancements.

Design, synthesis and activity evaluation of novel quinazolinone compounds as TRPC5 inhibitors

The TRPC5 channel plays an important role in regulating various physiological processes, which is related to various human diseases, especially psychiatric and kidney diseases. Although the TRPC5 channel is one of the essential potential target, no drugs against TRPC5 channels have been granted in the market to date. In this study, based on the structure of hit compound ph1, we further synthesied 49 compounds of novel quinazolinone and heterocyclic fusion pyrimidinone derivatives, and their activities were evaluated by electrophysiological assays. After extensive screening, 21 compounds exhibited significant TRPC5 inhibitory activity, and compounds ph8 and ph14 displayed strong inhibitory with IC50 of 1.28 and 2.16 μM, respectively. These identified potential TRPC5 inhibitor may provide lead compounds and experimental evidence for the development of novel TRPC5 inhibitors with potential treatment for anxiety, depression, and progressive kidney disease.

Lycorine esters exert anti-HCoV-OC43 effect through reversibly acylating cysteine residue in the nsp 12 NiRAN domain

By introducing ester warheads into the hydroxyl groups in lycorine (1), three types of lycorine mono-ester or di-ester analogues were synthesized and evaluated for their antiviral activities against HCoV-OC43. Most of them showed higher selective indexes (SI) than 1, up to nearly 14 times. Using compound 6b as a probe, we firstly demonstrated that lycorine esters directly targeted nidovirus RdRp-associated nucleotidyltransferase (NiRAN) domain in the non-structural protein 12 (nsp 12) by reversibly acylating Cys12 to induce the shrink of NiRAN pocket and block the viral replication, different from the known RdRp inhibitors. Meanwhile, the reversible acylation mode of lycorine esters guaranteed the higher SI values and long-acting effects of its kind. Thus, in addition to acting as prodrugs, ester compounds with a highly acylating warhead can be used as covalent probes to explore the detailed mode of action and improve the safety window. Compound 6b has been identified as a new reversible covalent RdRp allosteric inhibitor for further investigation.

Towards novel small-molecule inhibitors blocking PD-1/PD-L1 pathway: From explainable machine learning models to molecular dynamics simulation

Molecular design of small-molecule inhibitors targeting programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) pathway has been recognized as an active research area by the clinical success of cancer immunotherapy. In recent years, using machine learning (ML) methods to accelerate drug design have been confirmed. However, the black box character of ML methods makes model interpretation and ligands optimization obscured. Herein, five explainable ML models were constructed by integrating five ML models with the SHAP method, where these ML models were pretrained with >4000 molecules and their R2 ranged from 0.835 to 0.86 on test set. Subsequently, the explainable ML models were employed to identify the relationship between fragments and bio-activity of a small molecule inhibitor BMS-1166, leading to the modification of BMS-1166 into 60 novel compounds. After consensus docking and ADMET test, 3 small molecules (C27, C52 and C54) with better docking scores and lower toxicity than BMS-1166 were screened out further. Finally, the improved binding affinity of C27, C52 to the PD-L1 dimer was validated by the MD simulation. Overall, this work proposed an efficient protocol on the basis of explainable ML models for designing small-molecule inhibitors targeting PD-1/PD-L1 pathway in a rational way.

Discovery of novel pyrrolo[2,3-d]pyrimidine derivatives as anticancer agents: virtual screening and molecular dynamic studies

CDK/Cyclins are dysregulated in several human cancers. Recent studies showed inhibition of CDK4/6 was responsible for controlling cell cycle progression and cancer cell growth. In the present study, atom-based and field-based 3D-QSAR, virtual screening, molecular docking and molecular dynamics studies were done for the development of novel pyrrolo[2,3-d]pyrimidine (P2P) derivatives as anticancer agents. The developed models showed good Q2 and r2 values for atom-based 3D-QSAR, which were equal to 0.7327 and 0.8939, whereas for field-based 3D-QSAR the values were 0.8552 and 0.6255, respectively. Molecular docking study showed good-binding interactions with amino acid residues such as VAL-101, HIE-100, ASP-104, ILE-19, LYS-147 and GLU-99, important for CDK4/6 inhibitory activity by using PDB ID: 5L2S. Pharmacophore hypothesis (HHHRR_1) was used in the screening of ZINC database. The top scored ZINC compound ZINC91325512 showed binding interactions with amino acid residues VAL-101, ILE-19, and LYS-147. Enumeration study revealed that the screened compound R1 showed binding interactions with VAL 101 and GLN 149 residues. Furthermore, the Molecular dynamic study showed compound R1, ZINC91325512 and ZINC04000264 having RMSD values of 1.649, 1.733 and 1.610 Å, respectively. These ZINC and enumerated compounds may be used for the development of novel pyrrolo[2,3-d]pyrimidine derivatives as anticancer agent.

Discovery of a novel nanomolar angiotensin-I converting enzyme inhibitory peptide with unusual binding mechanisms derived from Chlorella pyrenoidosa

Chlorella pyrenoidosa (C. pyrenoidosa) has been cultivated in large quantities and proven to be antihypertensive when consumed orally. However, the antihypertensive peptides derived from C. pyrenoidosa remains scarce. In this study, trypsin was chosen to prepare the hydrolysate of C. pyrenoidosa, which was then fractionated by column chromatography. And ninety-nine peptides were identified by LC-MS/MS, after which 10 peptides were chosen by docking-based virtual screening and demonstrated their ability to inhibit ACE. Among them, LVAKA (LV-5) had the lowest IC50 (26.66 μM). LV-5, LKKAP, and PGLRP were identified as non-competitive ACE inhibitory peptides with significant stability under extreme pH and high temperatures conditions. Both in silico and in-vitro simulated gastrointestinal digestion revealed that these three peptides could release ACE inhibitory peptide fragments upon digestion. Sequence optimization of LV-5 led to the discovery of LRAKA (LR-5), which was identified as a novel nanomolar ACE peptide with an IC50 of 350 nM in-vitro and a potent antihypertensive peptide in-vivo. Moreover, molecular dynamic simulation indicated that LR-5 interacted with an unconventional binding site on ACE. These findings underscore the potential of Chlorella as a source of antihypertensive peptides and suggest a promising future for the use of Chlorella-derived peptides in hypertension management.

Utilization of the EpiMed Coronabank Chemical Collection to identify potential SARS-CoV-2 antivirals: in silico studies targeting the nsp14 ExoN domain and PLpro naphthalene binding site

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome encodes 29 proteins including four structural, 16 nonstructural (nsps), and nine accessory proteins (https://epimedlab.org/sars-cov-2-proteome/). Many of these proteins contain potential targetable sites for the development of antivirals. Despite the widespread use of vaccinations, the emergence of variants necessitates the investigation of new therapeutics and antivirals. Here, the EpiMed Coronabank Chemical Collection (https://epimedlab.org/crl/) was utilized to investigate potential antivirals against the nsp14 exoribonuclease (ExoN) domain. Molecular docking was performed to evaluate the binding characteristics of our chemical library against the nsp14 ExoN site. Based on the initial screen, trisjuglone, ararobinol, corilagin, and naphthofluorescein were identified as potential lead compounds. Molecular dynamics (MD) simulations were subsequently performed, with the results highlighting the stability of the lead compounds in the nsp14 ExoN site. Protein-RNA docking revealed the potential for the lead compounds to disrupt the interaction with RNA when bound to the ExoN site. Moreover, hypericin, cyanidin-3-O-glucoside, and rutin were previously identified as lead compounds targeting the papain-like protease (PLpro) naphthalene binding site. Through performing MD simulations, the stability and interactions of lead compounds with PLpro were further examined. Overall, given the critical role of the exonuclease activity of nsp14 in ensuring viral fidelity and the multifunctional role of PLpro in viral pathobiology and replication, these nsps represent important targets for antiviral drug development. Our databases can be utilized for in silico studies, such as the ones performed here, and this approach can be applied to other potentially druggable SARS-CoV-2 protein targets.

Pinpointing prime structural attributes of potential MMP-2 inhibitors comprising alkyl/arylsulfonyl pyrrolidine scaffold: a ligand-based molecular modelling approach validated by molecular dynamics simulation analysis

MMP-2 overexpression is strongly related to several diseases including cancer. However, none of the MMP-2 inhibitors have been marketed as drug candidates due to various adverse effects. Here, a set of sulphonyl pyrrolidines was subjected to validation of molecular modelling followed by binding mode analysis to explore the crucial structural features required for the discovery of promising MMP-2 inhibitors. This study revealed the importance of hydroxamate as a potential zinc-binding group compared to the esters. Importantly, hydrophobic and sterical substituents were found favourable at the terminal aryl moiety attached to the sulphonyl group. The binding interaction study revealed that the S1' pocket of MMP-2 similar to 'a basketball passing through a hoop' allows the aryl moiety for proper fitting and interaction at the active site to execute potential MMP-2 inhibition. Again, the sulphonyl pyrrolidine moiety can be a good fragment necessary for MMP-2 inhibition. Moreover, some novel MMP-2 inhibitors were also reported. They showed the significance of the 3rd position substitution of the pyrrolidine ring to produce interaction inside S2' pocket. The current study can assist in the design and development of potential MMP-2 inhibitors as effective drug candidates for the management of several diseases including cancers in the future.

Targeting key players in Alzheimer's disease: bioactive compounds from Moringa oleifera, Desmodium gangeticum, and Centella asiatica as potential therapeutics

Alzheimer's Disease (AD) is one of the critical reasons for dementia around the world, with a huge number of cases being reported every year. The breakdown of Amyloid Precursor Protein (APP) plays a crucial role in AD development. The Beta-site APP Cleaving Enzyme 1 (BACE1) is a highly significant proteolytic enzyme found to be critically involved in the APP breakdown process and generates beta-amyloid plaques in the extracellular neuronal membrane. In this study, we have used natural compounds with cognitive and neuroprotective activities from three plants, Centella asiatica, Moringa oleifera, and Desmodium gangeticum to inhibit the activity of BACE1. We have identified nine compounds out of 73 compounds filtered out from the three plants showing high affinity with the catalytic dyad region of BACE1 through molecular docking studies. Interestingly, the 200 ns molecular dynamics simulation study further confirmed the stability of the complexes formed between 9 compounds and the BACE1 protein. Furthermore, the free energy calculations also revealed these complexes possess favorable energies. Astilbin, Delphinidin 3-glucoside, and kaempferol 7-O-glucoside showed good binding affinity and structural stability when compared to other compounds and the control CNP520. Following a preliminary screening, the Astilbin compound was chosen based on the grounds of binding affinity, ADMET Properties, Hbond formation, Molecular Dynamic simulation, and MM-PBSA studies. A subsequent 1microsecond molecular dynamics simulation was conducted for the Astilbin complex. Through microsecond simulation, it was found that Astilbin alters BACE1's behavior and induces conformational rearrangements. Thus, this study opens a gateway to inhibit the activity of BACE1 protein through Astilbin thereby disclosing the possibility of managing Alzheimer's Disease.

Ligand and structure-based discovery of phosphorus-containing compounds as potential metalloproteinase inhibitors

In this study, a methodology is proposed, combining ligand- and structure-based virtual screening tools, for the identification of phosphorus-containing compounds as inhibitors of zinc metalloproteases. First, we use Dragon molecular descriptors to develop a Linear Discriminant Analysis classification model, which is widely validated according to the OECD principles. This model is simple, robust, stable and has good discriminating power. Furthermore, it has a defined applicability domain and it is used for virtual screening of the DrugBank database. Second, docking experiments are carried out on the identified compounds that showed good binding energies to the enzyme thermolysin. Considering the potential toxicity of phosphorus-containing compounds, their toxicological profile is evaluated according to Protox II. Of the five molecules evaluated, two show carcinogenic and mutagenic potential at small LD50, not recommended as drugs, while three of them are classified as non-toxic, and could constitute a starting point for the development of new vasoactive metalloprotease inhibitor drugs. According to molecular dynamics simulation, two of them show stable interactions with the active site maintaining coordination with the metal. A high agreement is evident between QSAR, docking and molecular dynamics results, demonstrating the potentialities of the combination of these tools.

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.