Lead Molecules Research Articles

Ultrapotent influenza hemagglutinin fusion inhibitors developed through SuFEx-enabled high-throughput medicinal chemistry

Seasonal and pandemic-associated influenza strains cause highly contagious viral respiratory infections that can lead to severe illness and excess mortality. Here, we report on the optimization of our small-molecule inhibitor F0045(S) targeting the influenza hemagglutinin (HA) stem with our Sulfur-Fluoride Exchange (SuFEx) click chemistry-based high-throughput medicinal chemistry (HTMC) strategy. A combination of SuFEx- and amide-based lead molecule diversification and structure-guided design led to identification and validation of ultrapotent influenza fusion inhibitors with subnanomolar EC50 cellular antiviral activity against several influenza A group 1 strains. X-ray structures of six of these compounds with HA indicate that the appended moieties occupy additional pockets on the HA surface and increase the binding interaction, where the accumulation of several polar interactions also contributes to the improved affinity. The compounds here represent the most potent HA small-molecule inhibitors to date. Our divergent HTMC platform is therefore a powerful, rapid, and cost-effective approach to develop bioactive chemical probes and drug-like candidates against viral targets.

Anti-vitiligo effect of Thespesia populnea L. bark against Tyrosinase enzyme using In-silico model

Background: Siddha medicine is one among the popular traditional systems of medicine in treating various diseases. Vitiligo is a primary autoimmune de-pigmentary disorder. Generally, melanin pigment production is diminished in vitiligo. By improving tyrosinase activity, melanogenesis can be achieved in vitiligo. Hence the phytocomponents which bind with the target Tyrosinase enzyme, act as a potential treatment for vitiligo. Objective: The objective of this study is to find the lead molecules that bind with these core bio active amino acid residues namely His 190, His54, His63, His194, His38 and His216.These bioactive residues mediates the enzymatic action of tyrosinase enzyme and tends to enhance the action of tyrosinase enzyme which improves melanogenesis. Methods: Auto dock program was used for the molecular docking studies against Tyrosinase enzyme. Results: From reported data of the herb, the phytochemicals Myricetin reveals highiest of 4 interactions with the core active amino acid residues of the target Tyrosinase enzyme.Second highiest level is reached by the compounds such as Catechin, Apigenin and Cinnamic acid with the 3 interactions with the active site . Gallic acid and Quercetin reveal 2 interactions over the target enzyme. From the results of docking study of the herb, the leads such as Catechin, Myricetin, Apigenin and Cinnamic acid possess 3-4 interactions with core target amino acids of Tyrosinase enzyme and helps in treatment and management of vitiligo. Conclusion: These phytochemicals exhibit anti-vitiligo activity by harmonising the action of tyrosinase enzyme in vitiligo treatment. Further clinical trials need to be performed for identifying the efficacy and effectiveness of Thespesia populnea in the treatment and management of vitiligo.

Baccharoides anthelmintica (L.) Moench: A Review on Ethnomedicinal, Phytochemical, Pharmacological and Toxicological Profile.

Baccharoides anthelmintica (L.) Moench is a popular medicinal plant with a long history of use in several traditional remedies to cure a variety of diseases including; its effect on the central nervous system, gastrointestinal tract, metabolism, kidneys, gynecology, skin diseases, and general health. The present review aims to provide the latest, organized information on toxicological, pharmacological, phytochemical, and ethnomedicinal applications of Baccharoides anthelmintica. For this; several well-known searchable websites (search engines) like; Web of Science, Google Scholar, Scopus-Elsevier, Taylor & Francis, Springer, and DOAJ, were used to empirically investigate the knowledge of this useful medicinal plant. Based on previous studies, the pharmacological action of B. anthelmintica is due to various secondary metabolites including alkaloids, terpenoids, lignans, steroids, and other phytoconstituents. Hence, the present study recorded 225 phytochemicals obtained from different parts of the plant, where the steroids and derivatives (48), terpenes and sesquiterpenes (46), flavonoids and derivatives (41), fatty acids and derivatives (40), phenolic acids (12), triterpenes (11), chalcones (06), diterpenes (01) and miscellaneous (20) were reported. The present review also covered the pharmacological importance, including antioxidant, antimicrobial, antiparasitic, antidiabetic, hypolipidemic action, liver disease, anticancer potential, anti-HIV, antiosteoporotic action, antitoxic action, skin disorder, wound healing and immunomodulatory activity, systemic infection, and treatment of neurodegenerative diseases etc. The review concluded that B. anthelmintica has several pharmacological activities, which were due to the presence of secondary metabolites present in it, and thus indicates the importance of medicinal value of this plant. Hence, B. anthelmintica may be a good source for developing a lead molecule in the process of new drug discovery and development. More study is required to determine the pharmacokinetics, mechanism of action, long-term toxicology testing, safe dosage, and possible interactions with other herbs/drugs.

A Recent Trends on Green Synthesis and Bioactivity of Imidazole

Imidazole is a five-membered, planar heterocyclic ring made up of 3C, 2N, and N in the 1st and 3rd places. Purine, histamine, histidine, and nucleic acid are only a few significant natural compounds that contain the imidazole ring. It is utilised as a cure to optimize the solubility and bioavailability properties of proposed weakly soluble lead compounds since it is an aromatic chemical that is polar and ionizable and so improves the pharmacokinetic features of lead molecules. Derivatives of imidazole have a special place in medicinal chemistry. An essential synthesis technique in the process of discovering new drugs is the integration of the imidazole nucleus. Due to the remarkable therapeutic efficacy of medications related to imidazole, medicinal chemists have been inspired to create numerous innovative chemotherapy agents. This review summarized the work that has been done in recent years about different synthetic approaches of imidazole derivatives and their potential activity as anti-HIV, anticancer, anticovid, antifungal, antidiabetic, antidepressant, antioxidant, and antituberculosis.

Investigating the molecular interactions of 11-substituted-1-(4-chlorophenyl)-8H-indolo[3,2-c][1,2,4]triazolo[3,4-a]isoquinolines for Antimicrobial Potential: Synthesis, Spectral, In vitro and In silico study interpretations

Indole molecules are one of the important scaffolds in the discovery and development of new drugs. We herein described a synthesis of new 11-substituted-1-(4-chlorophenyl)-8H-indolo[3,2-c][1,2,4]triazolo[3,4-a]isoquinoline 6 (a-h). Structures of the newly synthesized compounds were confirmed by making use of spectroscopic techniques like IR, NMR and mass. The DFT calculations were taken for the selected molecules using CAM-B3LYP hybrid functional with a 6–31+g(d) all-electron basis set using the Gaussian 09 package. The drug-likeness calculations were explained for the synthesized derivatives. The compounds 6b, 6c and 6 g exhibited excellent antibacterial, antifungal and anti-TB activities against tested pathogens at MIC 3.125 μg/ml. Furthermore, molecular docking studies of these compounds against S. aureus Gyrase (PDB ID:2XCT), Staphylococcus aureus tyrosyl-tRNA synthetase (PDB ID:1JIJ), and Mycobacterium tuberculosis enoyl reductase (INHA) (PDB ID:4TZK), revealed the potential binding mode of the ligands to the site of the appropriate targets. Finally, drug likeness and SAR studies were disclosed. Lastly, the protein stability, fluctuations of APO-Protein, and protein-ligand complexes were investigated through molecular dynamics simulations studies using Desmond Maestro 11.3 and potential lead molecules were identified.

Confronting Tuberculosis: A Synthetic Quinoline-Isonicotinic Acid Hydrazide Hybrid Compound as a Potent Lead Molecule Against Mycobacterium tuberculosis.

The current tuberculosis (TB) treatment is challenged by a complex first-line treatment for drug-sensitive (DS) TB. Additionally, the prevalence of multidrug (MDR)- and extensively drug (XDR)-resistant TB necessitates the search for new drug prototypes. We synthesized and screened 30 hybrid compounds containing aminopyridine and 2-chloro-3-formyl quinoline to arrive at a compound with potent antimycobacterial activity, UH-NIP-16. Subsequently, antimycobacterial activity against DS and MDR Mycobacterium tuberculosis (M.tb) strains were performed. It demonstrated an MIC50 value of 1.86 ± 0.21 μM for laboratory pathogenic M.tb strain H37Rv and 3.045 ± 0.813 μM for a clinical M.tb strain CDC1551. UH-NIP-16 also decreased the MIC50 values of streptomycin, isoniazid, ethambutol, and bedaquiline to about 45, 55, 68, and 76%, respectively, when used in combination, potentiating their activities. The molecule was active against a clinical MDR M.tb strain. Cytotoxicity on PBMCs from healthy donors and on human cell lines was found to be negligible. Further, blind docking of UH-NIP-16 using Auto Dock Vina and MGL tools onto diverse M.tb proteins showed high binding affinities with multiple M.tb proteins, the top five targets being metabolically critical proteins CelA1, DevS, MmaA4, lysine acetyltransferase, and immunity factor for tuberculosis necrotizing toxin. These bindings were confirmed by fluorescence spectroscopy using a representative protein, MmaA4. Envisaging that a pathogen will have a lower probability of developing resistance to a hybrid molecule with multiple targets, we propose that UH-NIP-16 can be further developed as a lead molecule with the bacteriostatic potential against M.tb, both alone and in combination with first-line drugs.

In-vitro and in-silico investigations of SLC-0111 hydrazinyl analogs as human carbonic anhydrase I, II, IX, and XII inhibitors.

Two novel series of hydrazinyl-based benzenesulfonamides 9a-j and 10a-j were designed and synthesized using SLC-0111 as the lead molecule. The newly synthesized compounds were evaluated for their inhibitory activity against four different human carbonic anhydrase (hCA) isoforms I, II, IX, and XII. Both the series reported here were practically inactive against the off-target isozyme hCA I. Notably, derivative 10a exhibited superior potency (Ki of 10.2 nM) than acetazolamide (AAZ) against the cytosolic isoform hCA II. The hCA IX and XII isoforms implicated in tumor progression were effectively inhibited with Kis in the low nanomolar range of 20.5-176.6 nM and 6.0-127.5 nM, respectively. Compound 9g emerged as the most potent and selective hCA IX and XII inhibitor with Ki of 20.5 nM and SI of 200.1, and Ki of 6.0 nM and SI of 683.7, respectively, over hCA I. Furthermore, six compounds (9a, 9h, 10a, 10g, 10i, and 10j) exhibited significant inhibition toward hCA IX (Kis = 27.0, 41.1, 27.4, 25.9, 40.7, and 30.8 nM) relative to AAZ and SLC-0111 (Kis = 25.0 and 45.0 nM, respectively). These findings underscore the potential of these derivatives as potent and selective inhibitors of hCA IX and XII over the off-target hCA I and II.

Multifunctional application of seagrass-derived rosmarinic acid in mitigating biofilm and quorum-sensing virulence transcripts of methicillin-resistant Staphylococcus aureus

Anti-microbial drug resistance is a primary public health concern, and the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) infections is gradually increasing. Considering the folk medicinal value of the seagrass Cymodocea rotundata and its antioxidant potential, the aim of this study was to assess C. rotundata for bioactive constituents that mitigate biofilm formation and quorum-sensing (QS) mechanism of MRSA. Different solvent extracts (chloroform, ethyl acetate, methanol, and distilled water) of C. rotundata were used, of which the methanolic extract exhibited maximum biofilm inhibition with complete cell lysis in 2 h. Column fractionation of the methanolic extract was performed, and 22 fractions were obtained. Fraction 7 exhibited maximum anti-biofilm potential, and the lead molecule was separated using thin-layer chromatography and characterized with high-performance liquid chromatography and nuclear magnetic resonance spectroscopy. The active constituent was identified as rosmarinic acid (RA), and the minimum inhibitory concentration was found to be 61.5 µg/mL; RA inhibited MRSA virulence factors such as protease by 89.37 %, lipase by 87.69 %, α-hemolysin by 91.52 %, and exopolysaccharides by 81.79 %, with an effective anti-adherence potential. Moreover, the lead molecule RA exhibited significant downregulation of QS-mediated virulence genes such as agrA, sarA, RNAIII, fnbA, fnbB, icaA, and icaD. Thus, seagrass C. rotundata has bioactive compounds with anti-microbial potential, and RA was found to control MRSA infection.

Molecular Docking and Dynamics Study of Acetogenins Targeting Cyclin-dependent Kinase and In vitro Evaluation of Annona Muricata Fruit Extracts using MDA-MB-231 Breast Cancer Cell Line

Background: Overexpressed CDK1 and CDK2 are targeted as potential sites for cancer treatment. Annona muricata fruit has been reported to have more than 100 acetogenins showing cytotoxic activities against cancer cell lines. Hence the study aims to demonstrate the cytotoxicity of ethyl acetate fruit extract, its role in cell cycle progression, and apoptosis using the MDMBA-231 breast cancer cell line. Docking, dynamics, and ADME studies were also demonstrated to generate lead molecules of AM fruit responsible for cancer treatment. Method: Cell viability was quantified by the MTT assay. Cell cycle arrest and apoptotic cells were determined by flow cytometry and PI annexin V-FITC staining by flow cytometry, respectively. Molecular docking, molecular dynamics, and ADME properties of 11 acetogenins were studied using the schrödinger maestro suite 2018-1. Results: The MTT assay revealed IC50 232.9μg/ml with a high degree of cytotoxicity. The extract effectively caused cell cycle arrest at the G2M and S phases; early and late apoptosis was induced at 160 μg/ml and 320 μg/ml. Docking scores of muricin L, J, and annomuricin A complexed with CDK2 and muricin J, K, and L with CDK1 binding energy ranging is mentioned as a molecular dynamic study envisaged muricin j against CDK2 stable hydrogen and hydrophobic interactions with critical residues like ASP-86, GLN-131, HIS-84, LYS-89, PHE80, PHE82, and PHE83 throughout 200 ns (hinge region). ADMET profiling also confirmed that all 11 ligands passed the rule of 5 and 3. The in vitro and in silico studies revealed that these acetogenins could be CDK1 and CDK2 inhibitors for cancer treatment. Conclusion: The in vitro studies presume that the ethyl acetate fruit extract of AM is an excellent cytotoxic agent. In silico studies demonstrated that muricin j could lead molecules to target kinase proteins responsible for cell proliferation. ADME study enlightened us to take 11 acetogenins for the drug discovery process in managing cancer treatment.

Docking of T6361 Analogues as Potential Inhibitors of E.coli MurA Followed by ADME-Toxicity Study.

Developing more potent antibacterial agents is one of the most important tasks of scientists in the health field due to the problem of antibiotic resistance. Among the antibiotic targets, we mention MurA (UDP-N-Acetylglucosamine Enolpyruvyl Transferase), which is a key enzyme of peptidoglycan biosynthesis of the bacterial cell wall. Our objective was to search for new inhibitors of the bacterial enzyme MurA by docking the analogues of its inhibitor T6361, a derivative of 5-sulfonoxy-anthranilic acid. 990 analogues of T6361 were docked in the first binding site of E.coli MurA (open form) using the FlexX program, and the ADME-Toxicity profile of the best ones was evaluated by SwissADME and PreADMET web servers. . Docking results revealed two T6361 analogues to provide better energy scores than T6361, and have similar interactions with the binding site of E.coli MurA namely,3-{[2-(piperidine-1-carbonyl) phenyl]sulfamoyl}benzoic acid and 3-{[2-(pyrrolidine-1 carbonyl)phenyl]sulfamoyl}benzoic acid. Moreover, the two molecules were found to possess good pharmacokinetics and low toxicity. We propose two analogues of T6361 as new potential inhibitors of MurA enzyme. Their good ADME-Toxicity profile qualifies them to reach in vitro and in vivo assays as future lead molecules.

Anticancer Activity of Novel 1,3,4-oxadiazole Derivatives against PARP-1 Inhibitors: An In-silico Approach

Background: Nuclear enzyme poly (ADP-ribose) polymerase-1 (PARP-1) controls the cell cycle, DNA repair, transcription, and replication processes. In this study, olaparib and rucaparib have been taken as standard drugs for comparison of results. As per previous research data, 1,3,4-Oxadiazole moiety has multidirectional biological activity and shows high activity against cancer. Objective: This study aimed to carry out the in silico ligand-based screening for the identification of hits for PARP1 inhibitors bearing 1,3,4-thiadiazole derivatives using Schrodinger suite 2022-1 and to perform MMGBSA and molecular dynamics simulation for lead molecules. Methods: A total of 32 derivatives of 1,3,4-Oxadiazole were designed with four different acids: phenoxy acetic acid, 1-Naphthoxy acetic acid, 2-Naphthoxy acetic acid, and piperonylic acid. Molecular docking (XP) studies were performed between 4ZZZ.pdb and the designed analogues, and the binding affinity values lay in the range of -8.52 to -3.52 kcal/mol. 2D interactions between the protein and the ligand were observed. Based on the binding affinity values and ADMET results, top 10 analogues were selected for performing MM-GBSA. Results: The dG-bind score of the top compounds varied from -2.30 to -60.67 kcal/mol, and analogue D4 was selected for MD simulation studies for 100ns. Results of Molecular dynamics (MD) studies showed that D4 interacted with amino acid residues, and the ligand-protein interaction stabilized from 58-90ns. The in silico study's findings suggested that the chemicals A1, A3, B1, B2, B3, B4, C1, C6, D1, and D4 might be significantly active against breast cancer with potential therapeutic benefits and are likely to be useful after further development. Conclusion: In conclusion, numerous molecules exhibit a high affinity for PARP-1 when derived from 1,3,4-oxadiazole. The in silico study's findings suggested that the chemicals A1, A3, B1, B2, B3, B4, C1, C6, D1, and D4 might be significantly active against breast cancer with potential therapeutic benefits and are likely to be useful after further development.

ChemoDOTS: a web server to design chemistry-driven focused libraries.

In drug discovery, the successful optimization of an initial hit compound into a lead molecule requires multiple cycles of chemical modification. Consequently, there is a need to efficiently generate synthesizable chemical libraries to navigate the chemical space surrounding the primary hit. To address this need, we introduce ChemoDOTS, an easy-to-use web server for hit-to-lead chemical optimization freely available at https://chemodots.marseille.inserm.fr/. With this tool, users enter an activated form of the initial hit molecule then choose from automatically detected reactive functions. The server proposes compatible chemical transformations via an ensemble of encoded chemical reactions widely used in the pharmaceutical industry during hit-to-lead optimization. After selection of the desired reactions, all compatible chemical building blocks are automatically coupled to the initial hit to generate a raw chemical library. Post-processing filters can be applied to extract a subset of compounds with specific physicochemical properties. Finally, explicit stereoisomers and tautomers are computed, and a 3D conformer is generated for each molecule. The resulting virtual library is compatible with most docking software for virtual screening campaigns. ChemoDOTS rapidly generates synthetically feasible, hit-focused, large, diverse chemical libraries with finely-tuned physicochemical properties via a user-friendly interface providing a powerful resource for researchers engaged in hit-to-lead optimization.

A structure-based pharmacophore modelling approach to identify and design new neprilysin (NEP) inhibitors: An in silico-based investigation

Neutral endopeptidase or neprilysin (NEP) cleaves the natriuretic peptides, bradykinin, endothelin, angiotensin II, amyloid β protein, substance P, etc., thus modulating their effects on heart, kidney, and other organs. NEP has a proven role in hypertension, heart disease, renal disease, Alzheimer's, diabetes, and some cancers. NEP inhibitor development has been in focus since the US FDA approved a combination therapy of angiotensin II type 1 receptor inhibitor (valsartan) and NEP inhibitor (sacubitril) for use in heart failure. Considering the importance of NEP inhibitors the present work focuses on the designing of a potential lead for NEP inhibition. A structure-based pharmacophore modelling approach was employed to identify NEP inhibitors from the pool of 1140 chemical entities obtained from the ZINC database. Based on the docking score and pivotal interactions, ten molecules were selected and subjected to binding free energy calculations and ADMET predictions. The top two compounds were studied further by molecular dynamics simulations to determine the stability of the ligand-receptor complex. ZINC0000004684268, a phenylalanine derivative, showed affinity and complex stability comparable to sacubitril. However, in silico studies indicated that it may have poor pharmacokinetic parameters. Therefore, the molecule was optimized using bioisosteric replacements, keeping the phenylalanine moiety intact, to obtain five potential lead molecules with an acceptable pharmacokinetic profile. The works thus open up the scope to further corroborate the present in silico findings with the biological analysis.

IN VITRO ANTIOBESITY ACTIVITY OF SOME PLANTS THROUGH A MODIFIED LIPASE INHIBITION ASSAY

The objective of the present study was to evaluate the antiobesity potential of various plant (leaves or seed) extracts through a modified in vitro lipase inhibitory activity assay. Dimethyl sulphoxide (DMSO, negative control or solvent) extracts as cold infusion of leaves and seeds of some plants were studied for lipase inhibitory potential using porcine pancreatic lipase enzyme, p- nitro phenyl acetate and orlistat (as positive control or standard inhibitor). Among the leaves, the Urtica dioica showed the best pancreatic lipase inhibition activity (52.0 %). On the other hand, among the seeds, Trachyspermum ammi showed the highest per cent lipase inhibition (91.68 %). Among six leaves’ and seven seeds’ extract, it was evident that the seeds showed better pancreatic lipase inhibition activity over the leaves in the study. The lipase inhibition was found to be in the range of 34.43 to 91.68 % for the plants in study. DMSO extract of the plants under the study showed significant pancreatic lipase inhibitory activity indicating strong antiobesity activity. Therefore, the plants can be further investigated for the identification and isolation of chief bioactive constituents for developing the lead molecules for obesity treatment.

Lead optimization based design, synthesis, and pharmacological evaluation of quinazoline derivatives as multi-targeting agents for Alzheimer's disease treatment

The complexity and multifaceted nature of Alzheimer's disease (AD) have driven us to further explore quinazoline scaffolds as multi-targeting agents for AD treatment. The lead optimization strategy was utilized in designing of new series of derivatives (AK-1 to AK-14) followed by synthesis, characterization, and pharmacological evaluation against human cholinesterase's (hChE) and β-secretase (hBACE-1) enzymes. Amongst them, compounds AK-1, AK-2, and AK-3 showed good and significant inhibitory activity against both hAChE and hBACE-1 enzymes with favorable permeation across the blood-brain barrier. The most active compound AK-2 revealed significant propidium iodide (PI) displacement from the AChE-PAS region and was non-neurotoxic against SH-SY5Y cell lines. The lead molecule (AK-2) also showed Aβ aggregation inhibition in a self- and AChE-induced Aβ aggregation, Thioflavin-T assay. Further, compound AK-2 significantly ameliorated Aβ-induced cognitive deficits in the Aβ-induced Morris water maze rat model and demonstrated a significant rescue in eye phenotype in the Aꞵ-phenotypic drosophila model of AD. Ex-vivo immunohistochemistry (IHC) analysis on hippocampal rat brains showed reduced Aβ and BACE-1 protein levels. Compound AK-2 suggested good oral absorption via pharmacokinetic studies and displayed a good and stable ligand-protein interaction in in-silico molecular modeling analysis. Thus, the compound AK-2 can be regarded as a lead molecule and should be investigated further for the treatment of AD.

Synthesis, in vitro and in silico screening of novel ferrocenyl substituted cyclohexenone and indazole derivatives as effective antimycobacterial agents

In response to the escalating threat of mycobacterial infections, including extensively drug-resistant tuberculosis (XDR) and multidrug-resistant tuberculosis (MDR), we synthesized novel ferrocene incorporating cyclohexenone and indazole derivatives. The compounds were synthesized via multistep reaction approach starting from chalcone precursors and evaluated against Mycobacterium fortuitum. The MIC and MBC values were calculated by following CLSI guidelines, with a focus on their ability to inhibit bacterial growth and disrupt biofilm formation. All the test compounds showed potent in vitro antimycobacterial activity against M. fortuitum. The MIC values range from 3.907 µg/mL to 500 µg/mL, whereas the MBC values range from 15.625 µg/mL to >500 µg/mL. Among the synthesized compounds, compound 3b exhibited potent antimycobacterial activity compared with standard drug Amikacin used to treat multidrug-resistant tuberculosis. 3b demonstrated significant inhibition of bacterial growth and showed the capacity to effectively suppress biofilm formation and disrupt pre-existing biofilms. This molecule also displayed favourable ADMET profile and good oral bioavailability, besides showing potential interactions with the target enzyme as revealed by docking studies and validated by enzyme assay. Collectively, these studies position 3b as a potential lead molecule that could be further optimized to develop ferrocene incorporating indazole based antimycobacterial agents.

Substituted 4H-3,1-benzoxazine-4-one Derivatives as Inhibitors of Cathepsin G.

Cathepsin G (CatG) is a cationic serine protease with a wide substrate specificity. CatG has been reported to play a role in several pathologies, including rheumatoid arthritis, ischemic reperfusion injury, acute respiratory distress syndrome, and cystic fibrosis, among others. We aim to develop a new class of CatG inhibitors and evaluate their potency and selectivity against a series of serine proteases. We exploited chemical synthesis as well as chromogenic substrate hydrolysis assays to construct and evaluate the new inhibitors. In this communication, we report on a new class of CatG inhibitors of 4H-3,1-benzoxazin- 4-one derivatives. We constructed a small library of seven substituted 4H-3,1-benzoxazin-4-one derivatives and identified their inhibition potential against CatG. Five molecules were identified as CatG inhibitors with values of 0.84-5.5 μM. Inhibitor 2 was the most potent, with an IC50 of 0.84 ± 0.11 μM and significant selectivity over representative serine proteases of thrombin, factor XIa, factor XIIa, and kallikrein. Thus, we propose this inhibitor as a lead molecule to guide subsequent efforts to develop clinically relevant potent and selective CatG inhibitors for use as anti-inflammatory agents.

Chemical Investigation of the Calcareous Marine Sponge Pericharax heteroraphis, Clathridine-A Related Derivatives Isolation, Synthesis and Osteogenic Activity.

As a result of screening a panel of marine organisms to identify lead molecules for the stimulation of endochondral bone formation, the calcareous sponge Pericharax heteroraphis was identified to exhibit significant activity during endochondral differentiation. On further molecular networking analysis, dereplication and chemical fractionation yielded the known clathridine A-related metabolites 3-6 and the homodimeric complex (clathridine A)2 Zn2+ (9), together with the new unstable heterodimeric complex (clathridine A-clathridimine)Zn2+ (10). With the presence of the zinc complexes annotated through the LC-MS analysis of the crude extract changing due to the instability of some metabolites and complexes constituting the mixture, we combined the isolation of the predicted molecules with their synthesis in order to confirm their structure and to understand their reactivity. Interestingly, we also found a large quantity of the contaminant benzotriazoles BTZ (7) and its semi-dimer (BTZ)2CH2 (8), which are known to form complexes with transition metals and are used for preventing corrosion in water. All isolated 2-aminoimidazole derivatives and complexes were synthesized not only for structural confirmation and chemical understanding but to further study their bioactivity during endochondral differentiation, particularly the positively screened imidazolone derivatives. Compounds leucettamine B, clathridine A and clathridimine were found to increase type X collagen transcription and stimulate endochondral ossification in the ATDC5 micromass model.

Ensemble-Based Virtual Screening Led to the Discovery of Novel Lead Molecules as Potential NMBAs.

Neuromuscular blocking agents (NMBAs) are routinely used during anesthesia to relax skeletal muscle. Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels; NMBAs can induce muscle paralysis by preventing the neurotransmitter acetylcholine (ACh) from binding to nAChRs situated on the postsynaptic membranes. Despite widespread efforts, it is still a great challenge to find new NMBAs since the introduction of cisatracurium in 1995. In this work, an effective ensemble-based virtual screening method, including molecular property filters, 3D pharmacophore model, and molecular docking, was applied to discover potential NMBAs from the ZINC15 database. The results showed that screened hit compounds had better docking scores than the reference compound d-tubocurarine. In order to further investigate the binding modes between the hit compounds and nAChRs at simulated physiological conditions, the molecular dynamics simulation was performed. Deep analysis of the simulation results revealed that ZINC257459695 can stably bind to nAChRs' active sites and interact with the key residue Asp165. The binding free energies were also calculated for the obtained hits using the MM/GBSA method. In silico ADMET calculations were performed to assess the pharmacokinetic properties of hit compounds in the human body. Overall, the identified ZINC257459695 may be a promising lead compound for developing new NMBAs as an adjunct to general anesthesia, necessitating further investigations.

Synthesis and biological evaluation of some novel benzoxazin-4-one and quinazolin-4-one derivatives based on anti-inflammatory commercial drugs

Benzoxazine and quinazoline are nitrogen-containing heterocyclic scaffolds found in various biologically active compounds. Due to their diverse biological actions, these heterocyclic rings serve as crucial frameworks for designing medicinal compounds. This study aimed to synthesize and assess in vivo anti-inflammatory, analgesic, and low ulcerogenic potential of a few novel benz[d][1,3]-oxazin-4-one and quinazolinone derivatives. Benzoxazinones (3a-e) were synthesized by cyclizing the carboxylic group (-COOH) of five nonsteroidal anti-inflammatory drugs viz., aceclofenac, ibuprofen, diclofenac, mefenamic acid and ketoprofen (2a-e) with anthranilic acid (1) using dry phosphorus oxychloride (POCl3) in pyridine. The corresponding quinazolinone derivatives (5a-e) were obtained by reacting 3a-e with isonicotinic acid hydrazide (4). Both sets of compounds were evaluated for their anti-inflammatory, analgesic effects, and ulcerogenicity in animal models. Structural characterization was performed using spectral analysis. Among the benzoxazinone derivatives, compound 2-(2-((2,6-dichlorophenyl) amino) benzyl)-4H-benzo[d][1,3]oxazin-4-one (3d) exhibited significant anti-inflammatory activity (62.61% inhibition of rat paw edema) and analgesic activity (62.36% protection in acetic acid-induced writhings) with tolerable gastrointestinal toxicity (2.67 ulcerogenicity index) compared to quinazolinone derivatives. The results of anti-inflammatory and analgesic activities of both the series are comparable with the respective, positive control. Compound 3d, a benzoxazinone-diclofenac hybrid, emerged as a lead molecule with potent anti-inflammatory, analgesic activities and moderate gastric toxicity showcasing the promising potential for further development.