Discovery of Novel Myristic Acid Derivatives as N-Myristoyltransferase Inhibitors: Design, Synthesis, Analysis, Computational Studies and Antifungal Activity.

In recent years, N-Myristoyltransferase (NMT) has been identified as a new target for the treatment of fungal infections. It is observed that at present, there are increased rates of morbidity and mortality due to fungal infections. Hence, a series of novel myristic acid derivatives were designed via molecular docking studies and ADMET studies by targeting NMT (N-Myristoyltransferase). The designed myristic acid derivatives were synthesized by converting myristic acid into myristoyl chloride and coupling it with aryl amines to yield corresponding myristic acid derivatives. The compounds were purified and characterized via FTIR, NMR and HRMS spectral analyses. In this study, we carried out a target NMT inhibition assay. In the NMT screening assay results, the compounds 3u, 3m and 3t showed better inhibition compared to the other myristic acid derivatives. In an in vitro antifungal evaluation, the myristic acid derivatives were assessed against Candida albicans and Aspergillus niger strains by determining their minimal inhibitory concentrations (MIC50). The compounds 3u, 3k, 3r and 3t displayed superior antifungal capabilities against Candida albicans, and the compounds 3u, 3m and 3r displayed superior antifungal capabilities against Aspergillus niger compared to the standard drug FLZ (fluconazole). Altogether, we identified a new series of antifungal agents.

Novel Derivatives of Eugenol as a New Class of PPARγ Agonists in Treating Inflammation: Design, Synthesis, SAR Analysis and In Vitro Anti-Inflammatory Activity.

The main objective of this research was to develop novel compounds from readily accessed natural products especially eugenol with potential biological activity. Eugenol, the principal chemical constituent of clove (Eugenia caryophyllata) from the family Myrtaceae is renowned for its pharmacological properties, which include analgesic, antidiabetic, antioxidant, anticancer, and anti-inflammatory effects. According to reports, PPARγ regulates inflammatory reactions. The synthesized compounds were structurally analyzed using FT-IR, 1HNMR, 13CNMR, and mass spectroscopy techniques. Molecular docking was performed to analyze binding free energy and important amino acids involved in the interaction between synthesized derivatives and the target protein. The development of the structure-activity relationship is based on computational studies. Additionally, the stability of the best-docked protein-ligand complexes was assessed using molecular dynamic modeling. The in-vitro PPARγ competitive binding Lanthascreen TR-FRET assay was used to confirm the affinity of compounds to the target protein. All the synthesized derivatives were evaluated for an in vitro anti-inflammatory activity using an albumin denaturation assay and HRBC membrane stabilization at varying concentrations from 6.25 to 400 µM. In this background, with the aid of computational research, we were able to design six novel derivatives of eugenol synthesized, analyzed, and utilized TR-FRET competitive binding assay to screen them for their ability to bind PPARγ. Anti-inflammatory activity evaluation through in vitro albumin denaturation and HRBC method revealed that 1f exhibits maximum inhibition of heat-induced albumin denaturation at 50% and 85% protection against HRBC lysis at 200 and 400 µM, respectively. Overall, we found novel derivatives of eugenol that could potentially reduce inflammation by PPARγ agonism.

Dynamacophore model for breast cancer estrogen receptor alpha as an effective lead generation screening technique.

Regardless to overwhelming quantum of cancer research worldwide, there are few drugs on the market to treat disease conditions. This is owing to multiple process inferences of drug targets in integrated pathways for invasion, growth, and metastasis. Over the past years, the death rate due to breast cancer has been increasing, that set the stage for improved better treatment. Therefore, there is a persistent and vital demand for innovative development of drugs to treat breast cancer. Many studies have reported that more than 60% of breast cancers are Estrogen receptor-α (ERα)-positive tumours and a key transcription factor, Estrogen receptor-α (ERα) was believed to promote proliferation of breast cancer cells. In this study, 150 ns of molecular dynamics was performed for protein-ligand complex to retrieve the potential stable conformations. The most populated dynamics cluster of 4-Hydroxytamoxifen intact with active site amino acid was selected to generate dynamacophore model (dynamic pharmacophore). Further, internal model validation with AU-ROC values ∼0.93 indicate the best model to screen library. The refined hits are funnelled in pharmacokinetics/dynamics, CDOCKER molecular docking, MM-GBSA and density functional theory to identify the promising ERα ligand candidates.Communicated by Ramaswamy H. Sarma.

Virtual Screening for Identification of Dual Inhibitors against CDK4/6 and Aromatase Enzyme.

CDK4/6 and aromatase are prominent targets for breast cancer drug discovery and are involved in abnormal cell proliferation and growth. Although aromatase inhibitors have proven to be effective (for example exemestane, anastrozole, letrozole), resistance to treatment eventually occurs through the activation of alternative signaling pathways, thus evading the antiproliferative effects of aromatase inhibitors. One of the evasion pathways is Cylin D-CDK4/6-Rb signaling that promotes tumor proliferation and resistance to aromatase inhibitors. There is significant evidence that the sequential inhibition of both proteins provides therapeutic benefits over the inhibition of one target. The basis of this study objective is the identification of molecules that are likely to inhibit both CDK4/6 and aromatase by computational chemistry techniques, which need further biochemical studies to confirm. Initially, a structure-based pharmacophore model was constructed for each target to screen the sc-PDB database. Consequently, pharmacophore screening and molecular docking were performed to evaluate the potential lead candidates that effectively mapped both of the target pharmacophore models. Considering abemaciclib (CDK4/6 inhibitor) and exemestane (aromatase inhibitor) as reference drugs, four potential virtual hit candidates (1, 2, 3, and 4) were selected based on their fit values and binding interaction after screening a sc-PDB database. Further, molecular dynamics simulation studies solidify the stability of the lead candidate complexes. In addition, ADMET and DFT calculations bolster the lead candidates. Hence, these combined computational approaches will provide a better therapeutic potential for developing CDK4/6-aromatase dual inhibitors for HR+ breast cancer therapy.

Estrogen receptor potentially stable conformations from molecular dynamics as a structure-based pharmacophore model for mapping, screening, and identifying ligands-a new paradigm shift in pharmacophore screening.

Despite rigorous research on breast cancer has increased in recent decades, only few drugs are in practice to combat against the disease. Due to excessive usage, these drugs attain resistance is an avertable phenomenon resulting from inadequate treatment. A novel, and real-time approaches are expected to overcome to find the solution for the drug resistance. The molecular dynamics based multi-conformational sampling technique via computer-aided drug-designing approach, may be a promising route to identify the lead candidates from real-time generated frames. The estrogenic receptor, being one of the most widely targeted receptors for various breast cancer drugs namely, tamoxifen, raloxifene and GW5 (tamoxifen-resistance inhibitor) was used for simulating the molecular dynamics to obtain various real time frames. The energetically stable frames were funnelled based on Gibbs free binding energy, interaction energy and active site interaction to generate pharmacophores model for virtual screening of compounds. Generated pharmacophores are validated by receiver operating characteristic area under curve greater than 0.8. Further, screening of compounds with validated structure-based pharmacophore model of different estrogen bound drug complex conformations and binding orientations are complement for tamoxifen and tamoxifen-resistance inhibitor frames. Moreover, the best mapped compounds were docked and probed for ADMET, TopKat® and Lipinski's rule of five is more favourable for compound Andrographidine F sourced from medicinal herbal plant Andrographis paniculata. Hence, this compound had to be further analysed in in-vitro and in-vivo to prove the same.Communicated by Ramaswamy H. Sarma.

Novel derivatives of eugenol as potent anti-inflammatory agents via PPARγ agonism: rational design, synthesis, analysis, PPARγ protein binding assay and computational studies.

Eugenol is a natural product abundantly found in clove buds known for its pharmacological activities such as anti-inflammatory, antidiabetic, antioxidant, and anticancer activities. It is well known from the literature that peroxisome proliferator-activated receptors (PPARγ) have been reported to regulate inflammatory responses. In this backdrop, we rationally designed semi-synthetic derivatives of eugenol with the aid of computational studies, and synthesized, purified, and analyzed four eugenol derivatives as PPARγ agonists. Compounds were screened for PPARγ protein binding by time-resolved fluorescence (TR-FRET) assay. The biochemical assay results were favorable for 1C which exhibited significant binding affinity with an IC50 value of 10.65 µM as compared to the standard pioglitazone with an IC50 value of 1.052 µM. In addition to the protein binding studies, as a functional assay, the synthesized eugenol derivatives were screened for in vitro anti-inflammatory activity at concentrations ranging from 6.25 µM to 400 µM. Among the four compounds tested 1C shows reasonably good anti-inflammatory activity with an IC50 value of 133.8 µM compared to a standard diclofenac sodium IC50 value of 54.32 µM. Structure-activity relationships are derived based on computational studies. Additionally, molecular dynamics simulations were performed to examine the stability of the protein-ligand complex, the dynamic behavior, and the binding affinity of newly synthesized molecules. Altogether, we identified novel eugenol derivatives as potential anti-inflammatory agents via PPARγ agonism.

Multi-conformational frame from molecular dynamics as a structure-based pharmacophore model for mapping, screening and identifying ligands against PPAR-γ: a new protocol to develop promising candidates.

Despite intensive research on clinical and molecular factors, the development of antidiabetic drugs in the last few decades is decelerating and as a result, the number of drugs approved by the US FDA is reduced. Hence, there is a persistent need for the innovative development of novel anti-diabetic drugs. Recent studies have provided ample proof that the peroxisome proliferator-activated receptor gamma (PPARγ), a ligand-activated transcription factor and its co-activator PGC-1 alpha may serve as good candidates for the treatment of several metabolic disorders. Therefore, in this study, 50 ns molecular dynamics (MD) simulations of the ligand-receptor complex were carried out and the most populated cluster of rosiglitazone bound to crucial amino acids during dynamics studies were selected to generate multi-conformation frame and further dynamic pharmacophore models. Finally, three pharmacophore models were generated, and 10 hits were retrieved as final lead candidates by virtual screening of ZINC database and molecular docking. The study reveals that the amino acids Met364, Lys367, His449, Leu453, Leu469, and Tyr473 play a crucial role in the binding of the compounds at the active site of PPARγ and the selected compounds from the ZINC database showed promising binding as compared to rosiglitazone. Further, ADMET studies were carried out to define the pharmacokinetic properties of promising PPARγ ligand candidates.Communicated by Ramaswamy H. Sarma.

Mapping of FSHR agonists and antagonists binding sites to identify potential peptidomimetic modulators.

Owing to the critical role of follicle stimulating hormone receptor (FSHR) signaling in human reproduction, FSHR has been widely explored for development of fertility regulators. Using high-throughput screening approaches, several low molecular weight (LMW) compounds that can modulate FSHR activity have been identified. However, the information about the binding sites of these molecules on FSHR is not known. In the present study, we extracted the structural and functional information of 161 experimentally validated LMW FSHR modulators available in PubMed records. The potential FSHR binding sites for these modulators were identified through molecular docking experiments. The binding sites were further mapped to the agonist or antagonist activity reported for these molecules in literature. MD simulations were performed to evaluate the effect of ligand binding on conformational changes in the receptor, specifically the transmembrane domain. A peptidomimetic library was screened using these binding sites. Six peptidomimetics that interacted with the residues of transmembrane domain and extracellular loops were evaluated for binding activity using in vitro cAMP assay. Two of the six peptidomimetics exhibited positive allosteric modulatory activity and four peptidomimetics exhibited negative allosteric modulatory activity. All six peptidomimetics interacted with Asp521 of hFSHR(TMD). Several of the experimentally known LMW FSHR modulators also participated in H-bond interactions with Asp521, suggesting its important role in FSHR modulatory activity.

A promising in silico protocol to develop novel PPARγ antagonists as potential anticancer agents: Design, synthesis and experimental validation via PPARγ protein activity and competitive binding assay.

Peroxisome proliferator-activated receptor gamma (PPARγ), a member of the nuclear receptor superfamily is an excellent example of targets that orchestrates cancer, inflammation, lipid and glucose metabolism. We report a protocol for the development of novel PPARγ antagonists by employing 3D QSAR based virtual screening for the identification of ligands with anticancer properties. The models are generated based on a large and diverse set of PPARγ antagonist ligands by the HYPOGEN algorithm using Discovery Studio 2019 drug design software. Among the 10 hypotheses generated, Hypotheses 2 showed the highest correlation coefficient values of 0.95 with less RMS deviation of 1.193. Validation of the developed pharmacophore model was performed by Fischer's randomization and screening against test and decoy set. The GH score or goodness score was found to be 0.81 indicating moderate to a good model. The selected pharmacophore model Hypo 2 was used as a query model for further screening of 11,145 compounds from the PubChem, sc-PDB structure database, and designed novel ligands. Based on fit values and ADMET filter, the final 10 compounds with the predicated activity of ≤ 3 nM were subjected for docking analysis. Docking analysis revealed the unique binding mode with hydrophobic amino acid that can cause destabilization of the H12 which is an important molecular mechanism to prove its antagonist action. Based on high CDocker scores, Cpd31 was synthesized, purified, analyzed and screened for PPARγ competitive binding by TR-FRET assay. The biochemical protein binding results matched the predicted results. Further, Cpd31 was screened against cancer cells and validated the results.

Gas chromatography-mass spectrometry metabolic profiling, molecular simulation and dynamics of diverse phytochemicals of Punica granatum L. leaves against estrogen receptor.

Introduction: Breast cancer is the most common type of cancer globally and its treatment with many FDA-approved synthetic drugs manifests various side effects. Alternatively, phytochemicals are natural reserves of novel drugs for cancer therapy. Punica granatum commonly known as pomegranate is a rich source of phytopharmaceuticals. Methods: The phytoconstituents of Punica granatum leaves were profiled using GC-MS/MS in the present work. Cytoscape-assisted network pharmacology of principal and prognostic biomarkers, which are immunohistochemically tested in breast cancer tissue, was carried out for the identification of protein target. Followed by, rigorous virtual screening of 145 phytoconstituents against the three ER isoforms (α, ß and γ) was performed using Discovery Studio. The docked complexes were further evaluated for their flexibility and stability using GROMACS2016 through 50 ns long molecular dynamic simulations. Results: In the current study, we report the precise and systematic GC-MS/MS profiling of phytoconstituents (19 novel metabolites out of 145) of hydromethanolic extract of Punica granatum L. (pomegranate) leaves. These phytocompounds are various types of fatty acids, terpenes, heterocyclic compounds and flavonoids. 4-coumaric acid methyl ester was identified as the best inhibitor of ER isoforms with drug-likeness and no toxicity from ADMET screening. γ-ligand binding domain complex showed the best interactions with minimum RMSD, constant Rg, and the maximum number of hydrogen bonds. Conclusion: We conclude that 4-coumaric acid methyl ester exhibits favourable drug-like properties comparable to tamoxifen, an FDA-approved breast cancer drug and can be tested further in preclinical studies.

Needleless electrospun phytochemicals encapsulated nanofibre based 3-ply biodegradable mask for combating COVID-19 pandemic.

The emergence of COVID-19 pandemic has severely affected human health and world economies. According to WHO guidelines, continuous use of face mask is mandatory for personal protection for restricting the spread of bacteria and virus. Here, we report a 3-ply cotton-PLA-cotton layered biodegradable face-mask containing encapsulated phytochemicals in the inner-filtration layer. The nano-fibrous PLA filtration layer was fabricated using needleless electrospinning of PLA & phytochemical-based herbal-extracts. This 3-layred face mask exhibits enhanced air permeability with a differential pressure of 35.78 Pa/cm2 and superior bacterial filtration efficiency of 97.9% compared to conventional face masks. Close-packed mesh structure of the nano-fibrous mat results in effective adsorption of particulate matter, aerosol particles, and bacterial targets deep inside the filtration layer. The outer hydrophobic layer of mask exhibited effective blood splash resistance up to a distance of 30 cm, ensuring its utilization for medical practices. Computational analysis of constituent phytochemicals using the LibDock algorithm predicted inhibitory activity of chemicals against the protein structured bacterial sites. The computational analysis projected superior performance of phytochemicals considering the presence of stearic acid, oleic acid, linoleic acid, and Arachidic acid exhibiting structural complementarity to inhibit targeted bacterial interface. Natural cotton fibers and PLA bio-polymer demonstrated promising biodegradable characteristics in the presence of in-house cow-dung based biodegradation slurry. Addition of jaggery to the slurry elevated the biodegradation performance, resulting in increment of change of weight from 07% to 12%. The improved performance was attributed to the increased sucrose content in biodegradation slurry, elevating the bacterial growth in the slurry. An innovative face mask has shown promising results for utilization in day-to-day life and medical frontline workers, considering the post-pandemic environmental impacts.

CDK4/6 inhibitors: a brief overview and prospective research directions.

The discovery of cyclin-dependent kinases (CDK) and their mechanism in regulating the cell cycle process was considered a game-changer in cancer therapy. Cell cycle arrest and apoptosis were both triggered by their inhibition. The CDK4/6 complex acts as a checkpoint during the cell cycle transition from cell growth (G1) to DNA synthesis (S) phase and its deregulation or overexpression induces abnormal cell proliferation and cancer development. Consequently, targeting CDK4/6 has been proposed as a paradigm shift in the anticancer approach. The design and development of effective CDK4/6 inhibitors are increasingly becoming a promising cancer therapy evident with approved drugs such as palbociclib, ribociclib, and abemaciclib, etc. In this article, we explore the biological importance of CDK4/6 in cancer therapy, the development of resistance to monotherapy, and a short overview of PROTAC (Proteolysis Targeting Chimera), a unique and pioneering technique for degrading CDK4/6 enzymes. Overall, our prime focus is to discuss novel CDK4/6 inhibitors with diverse chemical classes and their correlation with computational studies.

Curcumin to inhibit binding of spike glycoprotein to ACE2 receptors: computational modelling, simulations, and ADMET studies to explore curcuminoids against novel SARS-CoV-2 targets.

The recent emergence of the novel coronavirus (SARS-CoV-2) has raised global concern as it is declared a pandemic by the WHO. However, to date, there is no current regimen to mitigate the molecular pathogenesis of SARS-CoV-2 virus. Curcuminoids, bioactive ingredients present in Curcuma longa (turmeric), are known to exhibit diverse pharmacological properties. To the best of our understanding to date, SARS-CoV-2 uses angiotensin-converting enzyme 2 (ACE2) for the host cellular entry. This is mediated via proteins of SARS-CoV-2, especially the spike glycoprotein receptor binding domain. Accordingly, our primary objective is to thwart virus replication and binding to the host system, leading us to probe curcuminoids efficiency towards key surface drug target proteins using the computational biology paradigm approach. Specifically, fourteen natural curcuminoids were studied for their possibility of inhibiting SARS-CoV-2. We studied their in silico properties towards SARS-CoV-2 target proteins by homology modelling, ADME, drug-likeness, toxicity predictions, docking molecular dynamics simulations and MM-PBSA free energy estimation. Among the curcuminoids docked to the receptor binding domain of SARS-CoV-2 spike glycoprotein, the keto and enol forms of curcumin form strong hydrogen bond interactions with ACE2 binding residues Q493, T501, Y505, Y489 and Q498. Molecular dynamics simulations, free energy binding and interaction energy validated the interaction and stability of the docked keto and enol forms of curcumin.

Molecular Dynamics and Biological Evaluation of 2-chloro-7-cyclopentyl- 7H-pyrrolo[2,3-d]pyrimidine Derivatives Against Breast Cancer.

AIM AND OBJECTIVE: Inspired by the impressive biological properties of pyrrolo[2,3- d]pyrimidine units, the objective of this study was to synthesize some new derivatives of heterocyclic compounds with different substituent's using solvent-free microwave irradiation conditions from readily available starting material. The synthesized compounds were screened for their in vitro anti-microbial, anti-oxidant, anti-cancer activities and theoretical molecular docking studies. MATERIAL AND METHODS: Structural elucidation of the synthesized compounds was determined on the basis of various spectroscopic methods. Synthesized compounds have been evaluated for their in vitro antimicrobial activity (MIC) against various microbial strains. After the primary screening, synthesised compounds are further studied for anti-oxidant activity using DPPH assay method, anticancer activity against MCF-7 cell line using MTT assay and molecular docking studies. Moreover, molecular dynamics and simulation was done for best compound using GROMACS. RESULTS: A series of 2-chloro-7-cyclopentyl-7H-pyrrolo[2,3-d]pyrimidine derivatives 6(a-f), 7(a-c) and 8(a-c) were synthesised using solvent-free microwave irradiation technique. Among all the synthesized compounds, compounds 6e (51.35 µg/mL) and 6f (60.14 µg/mL) showed better activity profile against MCF-7 cell line for breast cancer activity. Compounds 6f and 6d have shown potent antibacterial activity against most of the employed strains, especially against S. pneumoniae, B. cerus and S. aureus. Compound 7a (52.21 µg/mL) showed high potential activity for antioxidant using DPPH assay. Molecular docking study showed good binding of these compounds to the active site of ER- alpha with binding energy ranging from -7.12 kcal/mol to -1.21 kcal/mol. Furthermore, molecular dynamics and simulation was conducted for best pose interacted compound 6e with active site of protein to study its stability and behaviour in nanoscale. CONCLUSION: The present research work is intended for facile and efficient green synthesis of various biologically useful potent bio-active molecules from inexpensive and readily available starting substrates under mild reaction condition. These classes of synthesized various heterocyclic compounds holds a great importance to discover newer anti-microbial, anti-oxidant and anti-cancer drugs in future prospects. Further structural modification in these structures will be of interest and may result in compounds having a better therapeutic and biological activity. Hence, this efficient green synthetic protocol and biological results of newly synthesized heterocyclic derivatives are found to be interesting lead molecules for bioactivity in the near future. It could be considered for investigation of their mode of action and for further development.

Recent Updates on Computer-aided Drug Discovery: Time for a Paradigm Shift.

Computer-Aided Drug Designing (CADD) has gained a wide popularity among biologists and chemists as a part of interdisciplinary drug discovery approach. It plays a vital role in the discovery, design and analysis of drugs in pharmaceutical industry. It is extensively used to reduce cost, time and speed up the early stage development of biologically new active molecules. In the current review we presented a brief review of CADD, merits and demerits, DNA, protein and enzyme as targets, types of CADD: Structure Based Drug Designing (SBDD), Ligand Based Drug Designing (LBDD), Pharmacophore based drug designing (PBDD) and Fragment Based Drug Designing (FBDD), theory behind the types of CADD and their applications. The review also focuses on the in-silico pharmokinetic, pharmacodynamic and toxicity filters or predictions that play a major role in identifying the drug like molecules. Currently in pharmaceutical sciences computational tools and software are exhibiting imperative role in the different stages of drug discovery hence the review throws light on various commercial and freeware available for each step of CADD.

Decolorization of Distillery Spent Wash Using Biopolymer Synthesized by Pseudomonas aeruginosa Isolated from Tannery Effluent.

A bacterial strain was isolated from tannery effluent which can tolerate high concentrations of potassium dichromate up to 1000 ppm. The isolated microorganism was identified as Pseudomonas aeruginosa by performing biochemical tests and molecular characterization. In the presence of excess of carbohydrate source, which is a physiological stress, this strain produces Polyhydroxybutyrate (PHB). This intracellular polymer, which is synthesized, is primarily a product of carbon assimilation and is employed by microorganisms as an energy storage molecule to be metabolized when other common energy sources are limitedly available. Efforts were taken to check whether the PHB has any positive effect on spent wash decolorization. When a combination of PHB and the isolated bacterial culture was added to spent wash, a maximum color removal of 92.77% was found which was comparatively higher than the color removed when the spent wash was treated individually with the PHB and Pseudomonas aeruginosa. PHB behaved as a support material for the bacteria to bind to it and thus develops biofilm, which is one of the natural physiological growth forms of microorganisms. The bacterial growth in the biofilm and the polymer together acted in synergy, adsorbing and coagulating the pollutants in the form of color pigments.