Coumarinyl pyranopyrimidines as new neuropeptide S receptor antagonists; design, synthesis, homology and molecular docking

Synthesis, molecular modelling and evaluation of larvicidal efficacy of annulated Benzo[h]chromenes against Culex pipiens L. Larvae

A new series of substituted benzo[h]chromene, benzochromenopyrimidine, and benzochromenotriazolopyrimidine derivatives were synthesized via chemical transformations of iminonitrile, ethoxymethylene amino, and cyanomethylene functionalities. The chemical structures of the synthesized compounds were assured by spectroscopic data and elemental analysis. The larvicidal efficacy of these compounds against Culex pipiens L. larvae was investigated, revealing potent insecticidal activity, particularly for compounds 6, 10, and 16, exceeding that of the standard insecticide chlorpyrifos. The mode of action of these compounds was explored through molecular docking studies, indicating their potential as acetylcholine esterase (AChE) inhibitors and nicotinic acetylcholine receptors (nAChR) blockers. The structure-activity relationship analysis highlighted the influence of substituents and fused heterocyclic rings on larvicidal potency. These findings suggest that the synthesized compounds hold promise as potential candidates for developing novel and effective mosquito control agents.

Pathophysiological and therapeutic implications of neuropeptide S system in neurological disorders

Neuropeptide S (NPS) is a 20 amino acids-containing neuroactive molecule discovered by the reverse pharmacology method. NPS is detected in specific brain regions like the brainstem, amygdala, and hypothalamus, while its receptor (NPSR) is ubiquitously expressed in the central nervous system (CNS). Besides CNS, NPS and NPSR are also expressed in the peripheral nervous system. NPSR is a G-protein coupled receptor that primarily uses Gq and Gs signaling pathways to mediate the actions of NPS. In animal models of Parkinsonism and Alzheimer's disease, NPS exerts neuroprotective effects. NPS suppresses oxidative stress, anxiety, food intake, and pain, and promotes arousal. NPSR facilitates reward, reinforcement, and addiction-related behaviors. Genetic variation and single nucleotide polymorphism in NPSR are associated with depression, schizophrenia, rheumatoid arthritis, and asthma. NPS interacts with several neurotransmitters including glutamate, noradrenaline, serotonin, corticotropin-releasing factor, and gamma-aminobutyric acid. It also modulates the immune system via augmenting pro-inflammatory cytokines and plays an important role in the pathogenesis of rheumatoid arthritis and asthma. In the present review, we discussed the distribution profile of NPS and NPSR, signaling pathways, and their importance in the pathophysiology of various neurological disorders. We have also proposed the areas where further investigations on the NPS system are warranted.

Discovery of benzochromene derivatives first example with dual cytotoxic activity against the resistant cancer cell MCF-7/ADR and inhibitory effect of the P-glycoprotein expression levels

A series of 1H-benzo[f]chromene moieties (4a-z) were synthesised under Ultrasonic irradiation and confirmed with spectral analyses. Derivative 4i solely possessed an X-ray single crystal. The anti-proliferative efficacy of the desired molecules has been explored against three cancer cells: MCF-7, HCT-116, and HepG-2 with the cytotoxically active derivatives screened against MCF-7/ADR and normal cells HFL-1 and WI-38. Furthermore, compounds 4b-d, 4k, 4n, 4q, and 4w, which possessed good potency against MCF-7/ADR, were tested as permeability glycoprotein (P-glycoprotein [P-gp]) expression inhibitors. The attained data confirmed that 4b-d, 4q, and 4w exhibited strong expression inhibition against the P-gp alongside its cytotoxic effect on MCF-7/ADR. The western blot results and Rho123 accumulation assays showed that compounds 4b-d, 4q, and 4w effectively inhibited the P-gp expression and efflux function. Meanwhile, 4b-d, 4q, and 4w induced apoptosis and accumulation of the treated MCF-7/ADR cells in the G1 phase and 4k and 4n in the S phase of the cell cycle.

EGFR and PI3K/m-TOR inhibitors: design, microwave assisted synthesis and anticancer activity of thiazole-coumarin hybrids

A series of thiazoline and thiazolidinone-based 4-hydroxycoumarin derivatives were synthesized using both conventional synthesis procedures and microwave-assisted techniques. The new compounds were evaluated for their cytotoxic effect against three human cancer cell lines; MCF-7, HCT-116 and HepG2 and one normal human cell line (BJ-1). The promising anti-proliferative compounds 2a, 2b, 6a and 6b were assessed for inhibiting EGFR and PI3K/mTOR. Compound 6a showed the highest inhibition activity towards the signaling pathway. The apoptotic effect and cell cycle arrest potential of derivative 6a were examined. Moreover, the molecular docking, physicochemical properties and pharmacokinetic parameters of the promising compound were investigated, as well.

Developing multitarget coumarin based anti-breast cancer agents: synthesis and molecular modeling study

A new series of 7-substituted coumarin scaffolds containing a methyl ester moiety at the C4-position were synthesized and tested for their in vitro anti-proliferative activity against MCF-7 and MDA-MB-231 breast cancer cell lines using Doxorubicin (DOX) as reference. Compounds 2 and 8 showed noticeable selectivity against MCF-7 with IC50 = 6.0 and 5.8 µM, respectively compared to DOX with IC50 = 5.6 µM. Compounds 10, 12, and 14 exhibited considerable selectivity against Estrogen Negative cells with IC50 = 2.3, 3.5, and 1.9 µM, respectively) compared to DOX with (IC50 = 7.3 µM). The most promising compounds were tested as epidermal growth factor receptor and aromatase (ARO) enzymes inhibitors using erlotinib and exemestane (EXM) as standards, respectively. Results proved that compound 8 elicited the highest inhibitory activity (94.73% of the potency of EXM), while compounds 10 and 12 displayed 97.67% and 81.92% of the potency of Erlotinib, respectively. Further investigation showed that the promising candidates 8, 10, and 12 caused cell cycle arrest at G0-G1 and S phases and induced apoptosis. The mechanistic pathway was confirmed by elevating caspases-9 and Bax/Bcl-2 ratio. A set of in silico methods was also performed including docking, bioavailability ADMET screening and QSAR study.

Synthesis and Molecular Docking of Some Novel 3-Thiazolyl-Coumarins as Inhibitors of VEGFR-2 Kinase

One crucial strategy for the treatment of breast cancer involves focusing on the Vascular Endothelial Growth Factor Receptor (VEGFR-2) signaling system. Consequently, the development of new (VEGFR-2) inhibitors is of the utmost importance. In this study, novel 3-thiazolhydrazinylcoumarins were designed and synthesized via the reaction of phenylazoacetylcoumarin with various hydrazonoyl halides and α-bromoketones. By using elemental and spectral analysis data (IR, ¹H-NMR, ¹³C-NMR, and Mass), the ascribed structures for all newly synthesized compounds were clarified, and the mechanisms underlying their formation were delineated. The molecular docking studies of the resulting 6-(phenyldiazenyl)-2H-chromen-2-one (3, 6a-e, 10a-c and 12a-c) derivatives were assessed against VEGFR-2 and demonstrated comparable activities to that of Sorafenib (approved medicine) with compounds 6d and 6b showing the highest binding scores (-9.900 and -9.819 kcal/mol, respectively). The cytotoxicity of the most active thiazole derivatives 6d, 6b, 6c, 10c and 10a were investigated for their human breast cancer (MCF-7) cell line and normal cell line LLC-Mk2 using MTT assay and Sorafenib as the reference drug. The results revealed that compounds 6d and 6b exhibited greater anticancer activities (IC₅₀ = 10.5 ± 0.71 and 11.2 ± 0.80 μM, respectively) than the Sorafenib reference drug (IC₅₀ = 5.10 ± 0.49 μM). Therefore, the present study demonstrated that thiazolyl coumarins are potential (VEGFR-2) inhibitors and pave the way for the synthesis of additional libraries based on the reported scaffold, which could eventually lead to the development of efficient treatment for breast cancer.

Induced-Fit Docking Enables Accurate Free Energy Perturbation Calculations in Homology Models

Homology models have been used for virtual screening and to understand the binding mode of a known active compound; however, rarely have the models been shown to be of sufficient accuracy, comparable to crystal structures, to support free-energy perturbation (FEP) calculations. We demonstrate here that the use of an advanced induced-fit docking methodology reliably enables predictive FEP calculations on congeneric series across homology models ≥30% sequence identity. Furthermore, we show that retrospective FEP calculations on a congeneric series of drug-like ligands are sufficient to discriminate between predicted binding modes. Results are presented for a total of 29 homology models for 14 protein targets, showing FEP results comparable to those obtained using experimentally determined crystal structures for 86% of homology models with template structure sequence identities ranging from 30 to 50%. Implications for the use and validation of homology models in drug discovery projects are discussed.

Pharmacology, Physiology and Genetics of the Neuropeptide S System

The Neuropeptide S (NPS) system is a rather ‘young’ transmitter system that was discovered and functionally described less than 20 years ago. This review highlights the progress that has been made in elucidating its pharmacology, anatomical distribution, and functional involvement in a variety of physiological effects, including behavior and immune functions. Early on, genetic variations of the human NPS receptor (NPSR1) have attracted attention and we summarize current hypotheses of genetic linkage with disease and human behaviors. Finally, we review the therapeutic potential of future drugs modulating NPS signaling. This review serves as an introduction to the broad collection of original research papers and reviews from experts in the field that are presented in this Special Issue.

New quinolone derivatives as neuropeptide S receptor antagonists: Design, synthesis, homology modeling, dynamic simulations and modulation of Gq/Gs signaling pathways

In a search for new neuropeptide S receptor antagonists, we have described a new series of quinolone-pyranopyrimidine hybrid derivatives aiming to modify the inhibitory characters towards NPSR to develop new therapeutic strategies against anxiety, addiction and food disorders. We identified six potent antagonists 3, 4b, 6, 8, 9 and 10 which counteracted the stimulatory effect of NPS at both Gq and Gs pathways, at low micromolar concentrations, through modulation of Ca²⁺ and cAMP signaling, respectively. Molecular docking predicted the orientation mode of the top active compounds; 10 and 4b with ΔG value of -23.94 and -23.87 kcal/mol, respectively that is considered good when compared to that of the reference compound ML154 (ΔG = -25.75 kcal/mol) . Molecular dynamic simulations confirmed the stability of binding of compound 10 to the homology model of NPSR as it reached the equilibrium after 4 ns at RMSD of 1.00 Å while ML154 was faster to achieve the equilibrium after 2 ns at RMSD of 1.00 Å.

Targeted potent antimicrobial benzochromene-based analogues: Synthesis, computational studies, and inhibitory effect against 14α-Demethylase and DNA Gyrase

7H-Benzo[7,8]chromeno[2,3-d]pyrimidin-9(8H)-amine (6a,b) have been synthesized via hydrazinolysis of the imidates (5a,b). Polysubstituted chromenotriazolopyrimidine (7a-j), (12a,b) and Schiff base (8a,b) derivatives have also been prepared. The new heterocyclic derivatives were affirmed by spectral data. The target compounds have been screened for antibacterial and antifungal activity. Compounds 6a,b and 7a-c, g,h displayed the most favorable antimicrobial activities in resemblance to the reference antimicrobial agents by IZ range over 24 mm. In addition, MIC, MBC and MFC were also tested and screen for most active compound 6a by 6.25 µg/mL showing bactericidal effect. SAR study revealed that the antimicrobial vitality of the target compounds was safely influenced by the lipophilicity substituents and the calculated log P value. The potent compounds were subjected into in vitro enzyme screening (14α-Demethylase and DNA Gyrase) against both interesting targets and showed good inhibitory profile. Molecular modeling analyses were introduced and discussed focusing on the docking of active compounds into two essential targets, and their ADMET properties were studied.

New 4-phenylcoumarin derivatives as potent 3C protease inhibitors: Design, synthesis, anti-HAV effect and molecular modeling

A new series of 4-phenylcoumarin derivatives was synthesized starting from (2-oxo-4-phenyl-2H-chromen-7-yloxy) acetic acid hydrazide 3. Evaluation of the target compounds for their antiviral activity against hepatitis A virus revealed that the ethylthiosemicarbazide derivative 7b was the most potent virucidal agent (IC50 = 3.1 μg/ml, TI = 83). The Schiff's bases 14c and 14b demonstrated the highest virustatic effects against viral adsorption and replication, respectively (14c; IC50 = 8.5 μg/ml, TI = 88 and 14b; IC50 = 10.7 μg/ml, TI = 91). Furthermore, compounds 7b, 14b and 14c were tested against HAV 3C protease and showed significant inhibition effects (Ki = 1.903, 0.104 and 0.217 μM, respectively). The remarkable inhibitory effect expressed by the three target compounds against HAV 3C protease prompted us to expand our research on HRV 3C protease, a structurally related enzyme of the same family, and interestingly, the three target compounds displayed significant inhibitory effect against HRV 3C protease (IC50 = 16.10, 4.13 and 6.30 μM, respectively). Moreover, the active compounds 7b, 14b and 14c were docked within the pocket site of HAV 3C protease (PDB code: 2HAL) illustrating a strong H-profile with the key amino acids Gly170 and Cys172 similar to the co-crystallized ligand. Furthermore, 3D-pharmacophore and quantitative structure activity relationship (QSAR) models were generated to explore the structural requirements for the observed antiviral activity.

Small Molecule Neuropeptide S and Melanocortin 4 Receptor Ligands as Potential Treatments for Substance Use Disorders

There is a vital need for novel approaches and biological targets for drug discovery and development. Treatment strategies for substance use disorders (SUDs) to date have been mostly ineffective other than substitution-like therapeutics. Two such targets are the peptide G-protein-coupled receptors neuropeptide S (NPS) and melanocortin 4 (MC4). Preclinical evidence suggests that antagonists, inverse agonists, or negative allosteric modulators of these receptors might be novel therapeutics for SUDs. NPS is a relatively unexplored receptor with high potential for treating SUD. MC4 has a strong link to early-onset obesity, and emerging evidence suggests significant overlap between food-maintained and drug-maintained behaviors making MC4 an intriguing target for SUD. This chapter provides an overview of the literature in relation to the roles of NPS and MC4 in drug-seeking behaviors and then provides a medicinal chemistry-based survey of the small molecule ligands for each receptor.

N-Alkyl-1,5-dideoxy-1,5-imino-l-fucitols as fucosidase inhibitors: Synthesis, molecular modelling and activity against cancer cell lines

1,5-Dideoxy-1,5-imino-l-fucitol (1-deoxyfuconojirimycin, DFJ) is an iminosugar that inhibits fucosidases. Herein, N-alkyl DFJs have been synthesised and tested against the α-fucosidases of T. maritima (bacterial origin) and B. taurus (bovine origin). The N-alkyl derivatives were inactive against the bacterial fucosidase, while inhibiting the bovine enzyme. Docking of inhibitors to homology models, generated for the bovine and human fucosidases, was carried out. N-Decyl-DFJ was toxic to cancer cell lines and was more potent than the other N-alkyl DFJs studied.