Evaluation of some new heterocycles bearing 2‐oxoquinolyl moiety as immunomodulator against highly pathogenic avian influenza virus ( H 5 N 8 )

Synthesis, in vivo evaluation, and in silico molecular docking of benzo[h]quinoline derivatives as potential Culex pipiens L. larvicides

A new series of benzo[h]quinoline-containing heterocycles was synthesized via reactions of benzo[h]quinolinyl-2(3H)-furanone with some nitrogen bidentate nucleophiles, leading to the formation of pyridazinone, pyrrolinone, benzimidazole, and benzoxazinone derivatives. The synthesized compounds were evaluated for their insecticidal activity against Culex pipiens L. larvae. Among these, pyridazinone 3 demonstrated the highest insecticidal activity with an LC50 value of 1.4 µg/mL (3.40 µM), significantly outperforming the reference insecticide chlorpyrifos. Molecular docking studies were conducted to explore the potential interactions between these compounds and key mosquito neuroreceptors, such as acetylcholinesterase (AChE), nicotinic acetylcholine receptors (nAChR), and the alpha subunit of voltage-gated sodium channels (VGSC). The docking results indicated strong binding affinities, suggesting that these derivatives could disrupt the normal functions of these neuroreceptors, contributing to their insecticidal activity. Additionally, molecular dynamics (MD) simulations were performed to assess the stability and binding interactions of compound 3 with AChE which revealed stable and strong interactions with key residues in the enzyme's active site, such as Trp212, Asp200, and Ile198, leading to reduced conformational flexibility and enhanced binding stability. These findings were further supported by MM-GBSA binding free energy calculations, which aligned with the compound's observed high inhibitory potency. The structure-activity relationship (SAR) analysis demonstrated that specific structural modifications, especially those involving pyridazinone and benzoxazinone frameworks, had a significant impact on the insecticidal potency of the derivatives. Additionally, ADME profiling indicated favorable pharmacokinetic properties, supporting the potential of these compounds as effective larvicides. This study presents novel insights into the synthesis and insecticidal potential of benzo[h]quinoline derivatives, which could contribute to developing more effective and sustainable solutions for controlling mosquito populations, especially amidst growing concerns of insecticide resistance in disease vectors.

Synthesis, insecticidal Activity, and molecular docking analysis of some benzo[h]quinoline derivatives against Culex pipiens L. Larvae

Some heterocycles bearing a benzo[h]quinoline moiety were synthesized through treating a 3-((2-chlorobenzo[h]quinolin-3-yl)methylene)-5-(p-tolyl)furan-2(3H)-one with four nitrogen nucleophiles comprising ammonium acetate, benzylamine, dodecan-1-amine, and 1,2-diaminoethane. Also, thiation reactions of furanone and pyrrolinone derivatives were investigated. The insecticidal activity of these compounds against mosquito larvae (Culex pipiens L.) was evaluated. All tested compounds exhibited significant larvicidal activity, surpassing that of the conventional insecticide chlorpyrifos. In silico docking analysis revealed that these compounds may act as acetyl cholinesterase (AChE) inhibitors, potentially explaining their larvicidal effect. Additionally, interactions with other neuroreceptors, such as nicotinic acetylcholine receptor and sodium channel voltage-gated alpha subunit were also predicted. The results obtained from this study reflected the potential of benzo[h]quinoline derivatives as promising candidates for developing more effective and sustainable mosquito control strategies. The ADME (absorption, distribution, metabolism, and excretion) analyses displayed their desirable drug-likeness and oral bioavailability properties.

Antiviral activity of pyrazole derivatives bearing a hydroxyquinoline scaffold against SARS-CoV-2, HCoV-229E, MERS-CoV, and IBV propagation

The ongoing global threat posed by coronaviruses necessitates the urgent development of effective antiviral agents. In this study, we investigated the potential of hydroxyquinoline-pyrazole candidates as antiviral agents against a range of coronaviruses, including SARS-CoV-2, MERS-CoV, and HCoV-229E. Molecular docking studies were conducted to assess the binding affinity of the synthesized compounds to key viral proteins. The compounds were prepared via condensation reactions of a pyrazolylhydrazide derivative with 2-chloro-3-formylquinoline, yielding hydrazone and pyrrolone derivatives. The cytotoxicity of compounds was evaluated using Vero E6 cells, and their antiviral activity was assessed via plaque reduction assays and viral inhibition assays using hydroxychloroquine as a positive control antiviral drug. The results revealed promising antiviral activity of the synthesized compounds against all tested coronaviruses, with selectivity indices indicating their potential as selective antiviral agents. Notably, the compounds exhibited potent inhibition of SARS-CoV-2 at lower concentrations, highlighting their promise as therapeutic candidates against this highly pathogenic virus. Likewise, the modeling pharmacokinetics approach showed its appropriate drug-likeness and bioavailability assets. These findings underscore the importance of hydroxyquinoline-pyrazole derivatives as potential antiviral agents against diverse coronaviruses, providing valuable insights for further therapeutic development.

Synthesis and cytotoxicity evaluation of novel 1,8-acridinedione derivatives bearing phthalimide moiety as potential antitumor agents

In this study, we aimed to develop hybrid antitumor compounds by synthesizing and characterizing novel N-substituted acrididine-1,8-dione derivatives, designed as hybrids of phthalimide and acridine-1,8-diones. We employed a three-step synthetic strategy and characterized all compounds using IR, 1H NMR, 13C NMR, and LC-MS. The cytotoxicity and antitumor activity of five compounds (8c, 8f, 8h, 8i, and 8L) against four cancer cell lines (H460, A431, A549, and MDA-MB-231) compared to human skin fibroblast cells were evaluated. Among the synthesized compounds, compound 8f showed promising activity against skin and lung cancers, with favorable IC50 values and selectivity index. The relative changes in mRNA expression levels of four key genes (p53, TOP2B, p38, and EGFR) in A431 cells treated with the five synthesized compounds (8c, 8f, 8h, 8i, and 8L) were also investigated. Additionally, molecular docking studies revealed that compound 8f exhibited high binding affinity with TOP2B, p38, p53, and EGFR, suggesting its potential as a targeted anticancer therapy. The results obtained indicate that N-substituted acrididine-1,8-dione derivatives have the potential to be developed as novel antitumor agents with a dual mechanism of action, and compound 8f is a promising candidate for further investigation.

Synthesis and antioxidant, antimicrobial, and antiviral activity of some pyrazole-based heterocycles using a 2(3H)-furanone derivative

Some pyrazole-based heterocycles such as pyrrolone, pyridazinone, and imidazole derivatives were synthesized utilizing the pyrazolyl-2(3H )-furanone derivative 3 , which was obtained in a good yield via Perkin condensation of 5-chloro-4-formyl-3-methyl-1-phenylpyrazole with 3-(4-methylbenzoyl)propionic acid in the presence of cyclo-dehydrating agent (sodium acetate and acetic anhydride). Also, the acid hydrazide obtained was reacted with some carbonyl reagents such as acetic anhydride, benzoyl chloride, 4-chlorobenzaldehyde, and 1,3-diphenyl-4-formylpyrazole, aiming to achieve new pyrrolone derivatives. The antioxidant, antimicrobial, and antiviral activity screening of some synthesized compounds demonstrated that some of them offered strong potencies. An experimental trial was undertaken to explore the effect of different substances and applied against avian influenza HPAI-H5N1 (AIV) to evaluate the antiviral replication in specific pathogen-free chicken embryos. All the compounds were screened for their antimicrobial activities, and most of tested compounds showed potent inhibition growth activity toward Haemophilus (Gram-negative bacteria), Staphylococcus aureus (Gram-positive bacteria), and Candida albicans fungus. Upon antimicrobial screening, it was observed that the majority of the compounds were found to be active against Staphylococcus aureus , Haemophilus , and Candida albicans as compared to standard drugs. This experiment shows the potential usage of these compounds as antiviral agents and can be considered as a viable means to control the economically important avian influenza of poultry. These compounds can thus be recommended for their antiviral, antibacterial, and antifungal property and can very well be used as immunostimulants.

Whole-Genome Sequence Analysis of an Endophytic Fungus Alternaria sp. SPS-2 and Its Biosynthetic Potential of Bioactive Secondary Metabolites

As one of the commonly isolated endophytic fungi, Alternaria has been known for the production of numerous secondary metabolites (SMs). However, its detailed genomic features and SM biosynthetic potential have not been extensively studied thus far. The present work focuses on the whole-genome sequencing and assembly of an endophytic strain Alternaria sp. SPS-2 derived from Echrysantha chrysantha Lindl. and gene annotation using various bioinformatic tools. The results of this study suggested that the genome of strain SPS-2 was 33.4 Mb in size with a GC content of 51% and an N50 scaffold of 2.6 Mb, and 9789 protein-coding genes, including 644 CAZyme-encoding genes, were discovered in strain SPS-2 through KEGG enrichment analysis. The antiSMASH results indicated that strain SPS-2 harbored 22 SM biosynthetic gene clusters (BGCs), 14 of which are cryptic and unknown. LS–MS/MS and GNPS-based analyses suggested that this endophytic fungus is a potential producer of bioactive SMs and merits further exploration and development.

Synthesis, SAR studies, and insecticidal activities of certain N-heterocycles derived from 3-((2-chloroquinolin-3-yl)methylene)-5-phenylfuran-2(3H)-one against Culex pipiens L. larvae

An acid hydrazide derivative was synthesized and transformed into a variety of valuable N-heterocycles such as pyridazinone, oxadiazole, triazolopyridazinone, and triazole derivatives via reactions with certain carbon electrophiles such as 4-methoxybenzaldehyde, indole-3-carbaldehyde, pentan-2,4-dione, and carbon disulfide. The chemical structures of all prepared compounds were verified via their analytical and spectroscopic data. The insecticidal activity of the N-heterocycles was evaluated against field and lab strains of the third larval instar of Culex pipiens. All tested compounds exhibited higher larvicidal activity against the lab strains compared to the field strains, with dissimilar ratios. The obtained results demonstrate that the high toxicity achieved by oxadiazole followed the order of furanone, pyridazinone and hydrazide, with lower LC₅₀ values of the hydrazone and N-acetylpyridazinone derivatives compared to that of imidacloprid. Interestingly, these compounds are promising agents for insect pest control, especially since they are insoluble in water and can overcome the disadvantages of neonicotinoid applications in pest management programs.

A new series of N-heterocycles including pyridazinone, oxadiazole, triazolopyridazinone, and triazole derivatives were synthesized from the acid hydrazide via its reaction with certain carbon electrophiles.

Synthesis, DFT, and eco-friendly insecticidal activity of some N-heterocycles derived from 4-((2-oxo-1,2-dihydroquinolin-3-yl)methylene)-2-phenyloxazol-5(4H)-one

A new series of nitrogen heterocycles encompassing a quinoline scaffold such as imidazolone, benzimidazole, triazinone, triazole, and thiazole derivatives was synthesized utilizing the readily obtainable building block synthon, 4-((2-oxo-1,2-dihydroquinolin-3-yl)methylene)-2-phenyloxazol-5(4H)-one (3). It was interesting that the fused heterocycle, pyranoquinoline derivative 15 was successfully synthesized by different routes of reactions. The synthesized compounds were evaluated for their insecticidal activity and compounds 6, 17, and 20 were the most potent against both Mythimna separata and Nilaparvata lugens. The DFT study was performed for the most potent compounds.