Construction of Donor-Acceptor-Type Conjugated Microporous Polymers by Oxidative Coupling of Boranil-Carbazole Mixed Monomers for Enhanced Photocatalytic Oxidation.

Conjugated microporous polymers (CMPs), featuring photoactive structures, a high surface area, robust thermal stability, and facile modulation, provide a versatile platform for fabricating diverse heterogeneous photocatalysts. The incorporation of donor-acceptor (D-A) structures into CMPs to increase their charge separation potential and enhance the photocatalytic efficacy is a viable strategy. In this work, we designed and synthesized a unique set of D-A monomers, incorporating boranil dyes as electron-deficient moieties and carbazoles as electron-rich subunits. Subsequently, D-A CMPs were prepared via an economical and environmentally friendly oxidation coupling reaction, and their potential in photocatalytic oxidation reactions was investigated. Modulation of the polymer's photoelectronic properties and photocatalytic performance can be achieved by adjusting the boranil content in the monomer. The polymer pCZFB-3, with the highest content of boranil units, exhibited an optimal photocatalytic activity. This finding confirms that strengthening the D-A effect can significantly enhance a catalyst's photoelectronic properties and catalytic efficacy. This study presents insights into designing innovative heterogeneous photocatalysts based on boron-containing dyes.

Discovery of 5-(Substituted Phenyl)-2-aryl Benzimidazole Derivatives as SIRT1 Activators: Their Design, in silico Studies, Synthesis, and in vitro Evaluation.

AIM: Silent information regulator two homologue one (SIRT1) is an emerging target for managing metabolic disorders. This study aimed to synthesize novel 5-(- substituted phenyl)-2-aryl benzimidazole derivatives and evaluate them for SIRT1 activation. METHODS: The compounds were designed according to the findings of the QSAR models framed in our previous studies. Molecular docking and dynamics studies were also performed to explore the interactions of designed compounds with the active site of the SIRT1 enzyme using AutoDock Vina and Schrödinger Maestro version 11.8.012, respectively. Compounds with good binding affinity were synthesized by Suzuki-Miyaura cross-coupling and spectrally characterized. The molecules were evaluated for their in vitro SIRT1 activation properties using a fluorescent screening kit. Based on the results of in vitro assay, a structure-activity relationship was established. SwissADME was employed to calculate the pharmacokinetics characteristics of the synthesized molecules. RESULTS: The molecular docking studies revealed that all the activators were effectively docked in the catalytic active site. All compounds demonstrated interactions with important amino acids like Glu230 and Arg446. In molecular dynamics simulations, the root mean square deviation (RMSD) of compound 5m and protein SIRT1 remained stable, i.e., below 3mm. Compound 5m, 4-(2-(3,4-dihydroxy-5-nitrophenyl)-1H-benzo[d]imidazol- 5-yl)benzaldehyde, was the most potent compound with an EC50 value of 0.006 mM (±0.001) and maximum activation of 240.5%. All the synthesized compounds had acceptable theoretical ADME profiles, and drug-likeness properties complied with Lipinski's rule. CONCLUSION: According to the findings, synthesized compounds may be viable leads for SIRT1 activators and may be used to advance preclinical in vivo research utilizing animal models.

2-Aryl-Benzoimidazoles as Type II NADH Dehydrogenase Inhibitors of Mycobacterium tuberculosis.

The nonproton pumping type II NADH dehydrogenase in Mycobacterium tuberculosis is essential for meeting the energy needs in terms of ATP under normal aerobic and stressful hypoxic environmental states. Type II NADH dehydrogenase conduits electrons into the electron transport chain in Mycobacterium tuberculosis, which results in ATP synthesis. Therefore, the inhibition of NDH-2 ensures the abolishment of the entire ATP synthesis machinery. Also, type II NADH dehydrogenase is absent in the mammalian genome, thus making it a potential target for antituberculosis drug discovery. Herein, we have screened a commercially available library of drug-like molecules and have identified a hit having a benzimidazole core moiety (6, H37Rv mc26230; minimum inhibitory concentration (MIC) = 16 µg/mL and ATP IC50 = 0.23 µg/mL) interfering with the oxidative phosphorylation pathway. Extensive medicinal chemistry optimization resulted in analogue 8, with MIC = 4 µg/mL and ATP IC50 = 0.05 µg/mL against the H37Rv mc26230 strain of Mycobacterium tuberculosis. Compounds 6 and 8 were found to be active against mono- and multidrug-resistant mycobacterium strains and demonstrated a bactericidal response. The Peredox-mCherry experiment and identification of single-nucleotide polymorphisms in mutants of CBR-5992 (a known type II NADH dehydrogenase inhibitor) were used to confirm the molecules as inhibitors of the type II NADH dehydrogenase enzyme. The safety index >10 for the test active molecules revealed the safety of test molecules.

Design and Synthesis of Benzimidazole Carboxamide Cysteine Protease Inhibitors as Promising Anti-leishmanial Agents.

INTRODUCTION: More than 20 protozoan species of Leishmania are responsible for causing Leishmaniasis, an infection spread by blood-feeding phlebotomine sandflies. A narrow pool of drugs is currently available rendering the current drug stratagem to treat this infection . Development of novel, less toxic, and more effective regimens is thus a need of the hour. Design and synthesis of benzo[d]imidazole carboxamides as agents to combat Leishmaniasis are also required. METHODS: 14 benzo[d]imidazole carboxamides were synthesized and gauged against L. donovani promastigotes and intramacrophage amastigote forms. All of the tested compounds exhibited significant anti-promastigote properties with IC50 well below 10 uM. Compounds 4a, 4b, and 4d, showing the highest anti-parasitic activity against promastigote forms (IC50 0.91- 1.33 µM), were also found to be associated with better anti-leishmanial potential (IC50 0.78- 1.67 µM) against the intramacrophage amastigotes comparable to Amphotericin-B (0.13 µM), a drug used for Leishmaniasis. Compound (4a), namely N-(2-(trifluoromethyl)-1Hbenzo[ d]imidazol-5-yl)benzo[d][1,3]-5-carboxamide-dioxole, was found to be most potent against L. donovani amastigotes among all the tested compounds, and demonstrated better antileishmanial properties (IC50 0.78 µM) when compared to the standard. Compound 4a was also assessed for its toxicity profile against THP-1 human monocytic cells. To establish the molecular target(s) in silico, molecular docking studies were performed against cysteine protease, a putative virulence factor of Leishmania parasites, and nucleoside diphosphate kinase, an enzyme with a critical role in nucleotide recycling, also associated with resistance in Leishmania strains. Compound 4a showed better binding affinity than the standard to these targets; furthermore, the molecular dynamic simulation studies further affirmed the stability of compound 4a, within the active site of the targets. In vitro, cysteine protease inhibitory activity (IC50 8.53 µM) using Bz-Arg-AMC hydrochloride fluorogenic peptide substrate established the promising potential of 4a as a cysteine protease inhibitor. RESULT: Computational ADMET analysis indicated appropriate pharmacokinetic profile and physicochemical characteristics for all members of the synthesized library. CONCLUSION: Both in vitro and in silico studies indicate that the synthesized imidazole carboxamides can act as potent hits and that N-(2-(trifluoromethyl)-1H-benzo[d]imidazol-5- yl)benzo[d][1,3]-5-carboxamide-dioxole 4a can be an effective hit molecule which can be further developed into potent lead molecule (s) to fight Leishmania donovani.

The thienopyridine A-769662 and benzimidazole 991 inhibit human TASK-3 potassium channels in an AMPK-independent manner.

Heteromeric Tandem pore domain Acid Sensitive (TASK)-1/3 channels are critical to oxygen-sensing by carotid body type 1 cells, where hypoxia-induced inhibition of TASK-3 and/or TASK-1/3 potassium currents leads to voltage-gated calcium entry, exocytotic transmitter release and increases in carotid body afferent input responses that initiate corrective changes in breathing patterns. It was proposed that, in response to hypoxia, the AMP-activated protein kinase (AMPK) might directly phosphorylate and inhibit TASK channels, in particular TASK-3, but studies on rat type I cells questioned this view. However, sequence alignment identified a putative AMPK recognition motif in human (h) TASK-3, but not hTASK-1, with Ser55 representing a potential phosphorylation site. We therefore studied the effects of five different AMPK activators on recombinant hTASK-3 potassium channels expressed in human embryonic kidney (HEK)-293 cells. Two structurally unrelated AMPK activators, the thienopyridine A-769662 (100-500 µM) and the benzimidazole 991 (3-30 µM) inhibited hTASK-3 currents in a concentration-dependent manner, while the 4-azabenzimidazole MK-8722 (3-30 µM) partially inhibited hTASK-3 at concentrations above those required for maximal AMPK activation. By contrast, the 4-azabenzimidazole, BI-9774 (10-100 µM; a closely related analogue of MK8722) and the pro-drug AICA-riboside (1 mM; metabolised to ZMP, an AMP-mimetic) had no significant effect on hTASK-3 currents at concentrations sufficient to maximally activate AMPK. Importantly, A-769662 (300 µM) also inhibited hTASK-3 channel currents in HEK-293 cells that stably over-expressed an AMPK-ß1 subunit mutant (S108A) that renders AMPK insensitive to activators that bind to the Allosteric Drug and Metabolite site, such as A-769662. We therefore identify A-769662 and 991 as novel hTASK-3 channel inhibitors and provide conclusive evidence that AMPK does not regulate hTASK-3 channel currents.

Potent α-glucosidase inhibitors with benzimidazole-propionitrile hybridization; synthesis, bioassay and docking study.

Background: Diabetes is characterized by a lack of insulin and insensitivity to insulin. In 2013, the global diabetes population was 382 million, with 90% of them having type 2 diabetes (non-insulin-dependent). It is predicted that this number will increase to 592 million by 2035.Aim: Here, we aimed to synthesize a series of benzimidazole-based derivatives B1-B32 with α-glucosidase inhibition potential as antidiabetic agents.Methods: Compounds B1-B32 were prepared in three three-step reactions, and the structures were elucidated using spectroscopic methods, namely 1H NMR, 13C NMR, MS and IR. Enzyme inhibition and kinetic study were done using commercial assay kits, and molecular docking study using autodock4.Results: Bioassay data showed that twenty-four out of the thirty-two tested compounds exhibited IC50 values ranging from 44 to 745 µM, surpassing the standard molecule, acarbose (IC50: 750 µM). it was determined that the best compound, B10, functions as a competitive inhibitor. Additionally, a molecular docking study provided insights into the interactions between the four most promising compounds (B5, B6, B10 and B28) and the active site residues within the enzyme.Conclusion: The tested compounds are interesting α-glucosidase inhibitors, which indicates the benefit of more bioassay studies, especially in vivo studies.

[Box: see text].

A Benzimidazole-Based N-Heterocyclic Carbene Derivative Exhibits Potent Antiproliferative and Apoptotic Effects against Colorectal Cancer.

Background and Objectives: Colorectal cancer (CRC) remains a major global health issue. Although chemotherapy is the first-line treatment, its effectiveness is limited due to drug resistance developed in CRC. To overcome resistance and improve the prognosis of CRC patients, investigating new therapeutic approaches is necessary. Materials and Methods: Using human colorectal adenocarcinoma (HT29) and metastatic CRC (SW620) cell lines, the potential anticancer properties of a newly synthesized compound 1-(Isobutyl)-3-(4-methylbenzyl) benzimidazolium chloride (IMBZC) were evaluated by performing MTT cytotoxicity, cell migration, and colony formation assays, as well as by monitoring apoptosis-related protein and gene expression using Western blot and reverse transcription-quantitative polymerase chain reaction technologies. Results: Tested at various concentrations, the half-maximal inhibitory concentrations (IC50) of IMBZC on HT29 and SW620 cell growth were determined to be 22.13 µM (6.97 µg/mL) and 15.53 µM (4.89 µg/mL), respectively. IMBZC did not alter the cell growth of normal HEK293 cell lines. In addition, IMBZC inhibited cell migration and significantly decreased colony formation, suggesting its promising role in suppressing cancer metastasis. Mechanistic analyses revealed that IMBZC treatment increased the expression of pro-apoptotic proteins p53 and Bax, while decreasing the expression of anti-apoptotic proteins Bcl-2 and Bcl-xL, thus indicating the induction of apoptosis in IMBZC-treated CRC cells, compared to untreated cells. Additionally, the addition of IMBZC to conventional chemotherapeutic drugs (i.e., 5-fluorouracil, irinotecan, and oxaliplatin) resulted in an increase in the cytotoxic potential of the drugs. Conclusions: This study suggests that IMBZC has substantial anticancer effects against CRC cells through its ability to induce apoptosis, inhibit cancer cell migration and colony formation, and enhance the cytotoxic effects of conventional chemotherapeutic drugs. These findings indicate that IMBZC could be a promising chemotherapeutic drug for the treatment of CRC. Further research should be conducted using in vivo models to confirm the anti-CRC activities of IMBZC.

Discovery of benzimidazole-2-amide BNZ-111 as new tubulin inhibitor.

Methyl benzimidazole-2-carbamate anthelmintics are a class of oral drugs to treat parasitic worm infections via microtubule disruption for non-systemic indications and currently in use. In order to use for anticancer treatment, the new benzimidazoles needs to improve solubility and pharmacokinetic parameters while maintaining its cellular potency as for systemic drug. Structure-activity-relationship on the benzimidazole is thoroughly examined and a novel benzimidazole-2 propionamide BNZ-111 is identified having good oral exposure and bioavailability in rat. Molecular docking study suggests BNZ-111 have a specific binding mode to the ß subunit of curved tubulin. BNZ-111 is potent to cancer cells and possesses good drug-like properties as oral drug. Especially, BNZ-111 is not a P-gp substrate and it demonstrates its efficacy over Paclitaxel-resistance tumor in vivo.

New Family of Benzimidazole-Based Chitosan Derivatives against Penicillium expansum.

Penicillium expansum is the major fungus that causes blue mold and produces patulin, threatening human health. Due to health and environmental pollution concerns, chitosan (CS) has attracted more and more attention as a safer alternative to synthetic fungicides for the control of blue mold. In the present study, four different benzimidazole groups were introduced onto CS by the acylation reaction to obtain benzimidazole-based chitosan derivatives (R1b-R4b). After being well-characterized with Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-vis spectra), and nuclear magnetic resonance (NMR), their antifungal activities against P. expansum were screened. Results showed that the inhibitory effects of chitosan derivatives against the pathogen were significantly correlated with chitosan derivatives' concentration and their structures. R4b was shown as optimum with good solubility and antifungal activity with a minimum inhibitory concentration (MIC) value of 0.5 mg/mL and a minimum fungicidal concentration (MFC) value of 2.0 mg/mL. The remarkable antifungal efficiency of R4b against P. expansum was further demonstrated in terms of spore germination, mycelial growth, patulin production, and the preliminary antifungal mechanism. R4b exhibited significant inhibition of patulin production, while its antifungal mechanism was revealed by destroying cell membrane integrity and inducing membrane depolarization. Furthermore, R4b treatment could significantly reduce the incidence of blue mold rot in apple fruit, and the MTT assay showed the nontoxicity of R4b against Raw 264.7, HBZY-1, and Caco-2 cells. Altogether, these results indicate that it is promising to be used as a fruit preservative in the future.

Chemotherapy for the treatment of alveolar echinococcosis: Where are we?

Alveolar echinococcosis (AE) is a severe liver disease due to infection with the Echinococcus multilocularis larval stage, called the metacestode. Management of AE is based on benzimidazole chemotherapy (albendazole or mebendazole), associated with surgery when possible. Benzimidazoles are the only compounds recommended for the treatment of AE; however, these are parasitostatic, which means that the parasite can resume growth when treatment is interrupted. Also, benzimidazoles can cause liver dysfunction which may prevent their use. Numerous drugs have been reported to have in vitro activity against E. multilocularis, but few had satisfactory in vivo activity, and none were clearly more effective than benzimidazoles. These drugs belong to various therapeutic categories including anti-infective agents (e.g. amphotericin B, mefloquine, pentamidine derivatives), anti-neoplastic compounds (e.g. imatinib, nilotinib, bortezomib), plant-extracted compounds (e.g. thymol, crocin, carvacrol) and others (e.g. metformin, verapamil, thiaclopride). These treatments are generally of limited interest due to their toxicity, their unfavorable pharmacokinetics, or the scarcity of studies involving humans. Apart from benzimidazoles, only amphotericin B, mefloquine and nitazoxanide have been reported to be used for human AE treatment, with unsatisfactory results. Few studies have aimed at developing innovative strategies for AE drug therapy, such as vectorization of drugs using nanoparticles. Altogether, this review emphasizes the urgent need for new therapeutic strategies in AE management, for which there is currently no curative chemotherapy.

Title: Chimiothérapie de l'échinococcose alvéolaire : où en sommes-nous ? Abstract: L'échinococcose alvéolaire (EA) est une maladie sévère du foie due à l'infection par la forme larvaire d'Echinococcus multilocularis, appelée métacestode. La prise en charge de l'EA repose sur la chimiothérapie par benzimidazolés (albendazole ou mébendazole), si possible associée à la chirurgie. Les benzimidazolés sont les seules molécules recommandées dans le traitement de l'EA, toutefois, ceux-ci sont parasitostatiques, ce qui signifie que le parasite peut reprendre sa croissance lors d'une interruption du traitement. Également, les benzimidazolés peuvent causer une dysfonction hépatique qui peut empêcher leur utilisation. De nombreux médicaments ont été rapportés comme ayant une activité in vitro contre E. multilocularis, mais peu d'entre eux avaient une activité in vivo satisfaisante et aucun n'était clairement plus efficace que les benzimidazolés. Ces médicaments appartiennent à diverses catégories, notamment les agents anti-infectieux (par exemple l'amphotéricine B, la méfloquine, des dérivés de la pentamidine), les composés antinéoplasiques (par exemple l'imatinib, le nilotinib, le bortézomib), les composés extraits de plantes (par exemple le thymol, la crocine, le carvacrol) et d'autres (par exemple metformine, vérapamil, thiaclopride). Ces traitements présentent généralement un intérêt limité en raison de leur toxicité, de leur pharmacocinétique défavorable ou de la rareté des études menées chez l'homme. Outre les benzimidazolés, seules l'amphotéricine B, la méfloquine et la nitazoxanide ont été utilisées dans le traitement de l'EA humaine, avec des résultats insatisfaisants. Peu d'études se sont intéressées à développer des stratégies médicamenteuses innovantes contre l'EA, comme la vectorisation de médicaments à l'aide de nanoparticules. Cette revue souligne le besoin urgent de nouvelles stratégies thérapeutiques dans la prise en charge de l'EA, pour lesquelles il n'existe pas de chimiothérapie curative.

Discovery of novel fructose-1,6-bisphosphatase inhibitors bearing benzimidazole scaffold using a dual-ligand molecular docking model.

Fructose-1,6-bisphosphatase (FBPase) is an emerging target in gluconeogenesis, inhibitors of which would be an effective treatment for elevated fasting blood glucose in patients with type 2 diabetes. Based on the lead compound G-1 (FBPase 10 µM inhibition = 64.3 %) and according to the X-ray crystal structure of FBPase, we designed and validated an innovative molecular docking method based on the dual-ligand model to explore the interactions between two identical ligands in neighboring targets. Based on the dual-ligand molecular docking model, a novel compound 45 bearing a benzimidazole scaffold was identified to show increased inhibitory activity against FBPase (IC50, 2.08 µM). An oral pyruvate tolerance test in ICR mice showed that 45 had a potent inhibitory effect on gluconeogenesis similar to that of metformin when administered as a single dose in vivo. Compound 45 did not inhibit the common subtypes of the human cytochrome P450 system, indicating that it may have a reduced propensity for drug-drug interactions. The findings of this study may pave the way for further development of FBPase inhibitors with novel structural features, improved activity, and good druggability.

Benzimidazole-acrylonitrile hybrid derivatives act as potent urease inhibitors with possible fungicidal activity.

Aim: A series of benzimidazole-acrylonitrile derivatives TM1-TM53 were designed with urease inhibition approach.Materials & methods: TM1-TM53 were synthesized and characterized (1H Nuclear Magnetic Resonance (NMR), 13C NMR, Mass Spectroscopy (MS) and IR) and subjected to urease inhibition assay using commercial assay kit. A molecular docking study was also performed using Autodock tool software.Results: Except six compounds, target molecules exhibited a higher urease inhibition effect (IC50: 1.22-28.45 µM) than hydroxyurea (IC50: 100 µM). kinetic study on TM11, clarified its mode of action as a mixed inhibitor. A molecular docking study on TM6, TM11 and TM21, was performed and the results showed the main residues inside the active site of the enzyme. All TM1-TM53 were also studied in silico using molecular docking techniques to evaluate their potential to inhibit succinate dehydrogenase in comparison to fluxapyroxad as standard. Docking study revealed the high potential of TM1-TM53 as a fungicides.Conclusion: Obtained results exhibited the high activity of benzimidazole-acrylonitrile derivatives as urease inhibitors and their possible potential as fungicide agents. So, it will be beneficial to do more bioactivity investigation on this family of compounds.

[Box: see text].

Novel benzimidazole-based azine derivatives as potent urease inhibitors: synthesis, in vitro and in silico approach.

Aim: In light of various biological activities of benzimidazole and azines, this study focuses on reporting novel derivatives of benzimidazole nucleus.Methods: Twenty novel azines of benzimidazole were synthesized, characterized and tested for in vitro urease inhibitory activity.Results: All these derivatives showed excellent to good inhibition in the range of IC50 values 14.21 ± 1.87 to 76.11 ± 1.81 µM by comparing with standard thiourea 21.14 ± 0.42 µM. Docking studies were performed for the targeted benzimidazole derivatives to understand the binding mechanics. The results indicated higher binding efficacy compared with the reference inhibitor.Conclusion: This work identifies potential lead candidates for novel urease inhibitors, which with industrial support may be harnessed for the development of new drugs.

[Box: see text].

Prevalence status and detection of benzimidazole resistance using AS-PCR in Haemonchus contortus of goats from Marathwada region, Maharashtra, India.

This study examined Haemonchus contortus prevalence and benzimidazole resistance in eight districts of Marathwada, Maharashtra, India. A comprehensive investigation of 264 abomasa of goats collected from abattoirs and goats necropsied at the College of Veterinary Sciences and Animal Husbandry, Parbhani, revealed 21.21 % a prevalence of H. contortus. The incidence of H. contortus did not vary much across seasons and it was highest in summer (23.42 %), followed by monsoon (22.89 %), and lowest in winter (15.71 %). Statistically non-significant (p < 0.05) prevalence was observed in male and female animals. A detailed examination of 168 adult H. contortus worms from eight districts revealed the presence of all conceivable genotypes including homozygous resistant (rr), susceptible (SS), and heterozygous (Sr) BZ susceptible genotypes. The rr was the most frequent at 50 %, followed by SS at 27 % and Sr at 22 %. The presence of the SNP was observed in in all eight randomly selected and sequenced samples.

In-situ strategies for melamine-functionalized graphene oxide nanosheets-based nanocomposite proton exchange membranes in wide-temperature range applications.

The traditional preparation of nanocomposite proton exchange membranes (PEM) is hindered by poor organic-inorganic interface compatibility, insufficient proton-conducting sites, easy aggregation of nanoparticles, and difficulty in leveraging nanoscale advantages. In this study, a novel method involving electrochemical anodic oxidation exfoliation was employed to prepare melamine-coated graphene oxide (Me@GO), which was subsequently subjected to in-situ polymerization with poly(2,5-benzimidazole) (ABPBI) to prepare a Me@GO/ABPBI composite proton exchange membrane. Benefiting from the strong hydrogen bonding and large π stacking interactions, melamine (Me) tightly bound to graphene oxide (GO), effectively preventing the secondary aggregation of GO after exfoliation. Moreover, the abundant alkaline functional groups of melamine enhanced the enhancement of phosphoric acid (PA) retention in the Me@GO/ABPBI membranes, thereby increasing the number of proton-conducting sites. The experimental results indicated that the introduction of Me@GO enhanced membrane properties. For Me@GO at a concentration of 1 wt%, the tensile strength of the 1Me@GO/ABPBI composite membrane reached 207 MPa, nearly 2.52 times that of the pure membrane. The proton conductivity of the 1Me@GO/ABPBI composite membrane reached 0.01 S cm-1 across a wide temperature range (40-180 °C), peaking at 0.087 S cm-1 at 180 °C. Additionally, a single-cell incorporating the 1Me@GO/ABPBI composite membrane achieved a peak power density of 0.304 W cm-2 at 160 °C, nearly 1.46 times that of the pure membrane. Benefiting from the well-dispersed and PA-enriched proton channels provided by Me@GO, the Me@GO/ABPBI composite membrane exhibits excellent prospects for wide-temperature range (40-180 °C) applications.

Design, synthesis, characterization, and biological activities of novel Ag(I)-NHC complexes based on 1,3-dioxane ligand.

Herein, a series of new Ag(I)-NHC complexes containing 1,3-dioxane group were synthesized by the direct reaction of Ag2O and benzimidazolium salts in light-free conditions. All Ag(I)-NHC complexes were spectrally characterized using 1H, 13C NMR, FT-IR, LC-MS, and elemental analysis. Additionally, the structures of compounds 1a and 1e were elucidated by the single X-ray diffraction techniques. Further, the synthesized Ag(I)-NHC complexes were evaluated for cytotoxicity study on the L-929 cells and the anticancer activity against the HCT 116 and MCF-7 cancer cell lines. Notably, 1a showed significant anticancer activity against HCT 116 with an IC50 of 6.37 ± 0.92 µg/mL compared to cisplatin (IC50 = 36.75 ± 1.76 µg/mL). 1c (IC50 = 3.21 ± 1.96 µg/mL) and 1e (IC50 = 3.72 ± 1.12 µg/mL) exhibited significant anticancer activity against MCF-7 cells and was similar to cisplatin (IC50 = 32.17 ± 2.85 µg/mL). Meanwhile, 1a and 1e displayed the highest selectivity index. Most importantly, the cell viability test showed that 1e induced neglectable cytotoxicity (IC50 = 36.38 ± 2.27 µg/mL) toward L-929 and was similar to cisplatin (IC50 = 36.11 ± 2.09 µg/mL). The anticancer activities of Ag(I)-NHC complexes vary depending on the substituent group of the silver complex and the cell line type. Moreover, the inhibitory mechanism of 1e was not dependent on caspase-associated apoptosis initiated by the lysosomal-mitochondrial pathway. Taken together, we conclude that this work provides a simple and rapid protocol for the synthesis of Ag(I)-NHC complexes and the featured Ag(I)-NHC complexes have an anticancer drug potential for biomedical applications.

The first molecular detection of benzimidazole resistance in Haemonchus contortus from sheep in Hejing and Minfeng counties of Southern Xinjiang.

To understand the benzimidazole (BZ) resistance of Haemonchus contortus in Southern Xinjiang, three single nucleotide polymorphisms (SNPs) designated as F167Y, E198A, and F200Y, in the isotype-1 ß-tubulin gene which are associated with BZ resistance, were investigated for H. contortus populations from sheep in Hejing and Minfeng counties of Southern Xinjiang. In brief, a total of 190 H. contortus adults were collected from 52 out of 70 slaughtered sheep in city abattoirs across two regions in Southern Xinjiang. The species identity of each adult worm was confirmed by PCR amplification of ITS-2 using H. contortus-specific primers targeting the ITS-2. The samples were then investigated for BZ-related SNPs at locus 167, 198, and 200, by PCR-sequencing of the isotype-1 ß-tubulin gene. The results showed that only E198A and F200Y mutations were detected in the investigated H. contortus populations. The E198A mutation (homozygous and heterozygote resistant: found in 40% and 30% of sequenced samples from Minfeng and Hejing counties, respectively) was predominant compared with the F200Y mutation (homozygous and heterozygote resistant: found in 14% and 13.3% of sequenced samples from Minfeng and Hejing counties, respectively). The results indicate a high prevalence of BZ resistance in H. contortus populations from certain areas of Southern Xinjiang. Our findings provide valuable information for the prevention and control of H. contortus in areas with similar conditions.

Metabolic characterization of the new benzimidazole synthetic opioids - nitazenes.

The recent re-emergence and the increasing popularity of nitazenes, a group of new synthetic opioids (NSO) that belong to the benzimidazole chemical class, has raised public health concerns. As a class of potential opioid analgesic agents whose development was discontinued in the 1960s due to their high potential for abuse, very little is known about their metabolism and physiologic disposition. In the current study, three nitazenes-butonitazene, isotonitazene and protonitaze were incubated in human liver microsomes (HLM), human S9 (HS9) fractions and recombinant cytochrome P450 enzymes. All three nitazenes were rapidly metabolized in both HLM and HS9 with over 95% depletion within 60 min. In HLM, butonitazene, isotonitazene and protonitazene had in vitro intrinsic clearance (CLint) (µL/min/mg protein) values of 309, 221 and 216 respectively compared to 150 of verapamil, the positive control. In HS9, CLint values were 217, 139, and 150 for butonitazene, isotonitazene and protonitazene respectively compared to only 35 for testosterone, the control probe substrate. Putative metabolite identified from this study include products of hydroxylation, desethylation, dealkylation, desethylation followed by dealkylation, and desethylation followed by hydroxylation. The metabolic phenotyping showed CYP2D6, CYP2B6 and CYP2C8 and the major hepatic enzymes responsible for the metabolism of nitazenes. Within 30 min of incubation, CYP2D6 depleted butonitazene (99%), isotonitazene (72%) and butonitazene (100%) significantly. The rapid metabolism of nitazenes may be an important factor in accurate and timely detections and quantitation of the unchanged drugs in human matrices following intoxication or in forensic analysis. The involvement of multiple polymorphic CYPs in their metabolism may play important roles in the susceptibility to intoxication and/or addiction, depending on the activity of the metabolites.

Highly Reversible "On-Off-On" Fluorescence Switch Governed by pH, Utilizing Bis(Benzimidazole) Derivatives with Varied Link Groups.

In this work, a series of dibenzimidazole derivatives 1-4, act as highly reversible colorimetric and fluorescent pH chemosensor, were designed and synthesized. Excellent reversible pH response of these sensors could be found by a specific pH change through obvious fluorescent color changes. The response is not affected by common cations (including Al3+, Cu2+, Ca2+, Cd2+, Co2+, Cr3+, Mg2+, Na+, K+, Ni2+, Pb2+ and Zn2+) and anions (including F-, Cl-, Br-, I-, ClO4-, H2PO4-, HSO4-, HCO3- and CH3COO-). Notably, these sensors can be reused more than 10 times without losing functionality. Unlike previous reports, the distinct properties of 1-4 are attributed to the varied link groups. Based on comprehensive experimental data and mechanistic analyses, it is concluded that sensors 1-4 are promising candidates for use as highly reversible "on-off-on" fluorescence switches under precise pH control.

Design, synthesis, and antifungal activity of novel pyrazole carboxamide derivatives containing benzimidazole moiety as potential SDH inhibitors.

To address the urgent need for new antifungal agents, a collection of novel pyrazole carboxamide derivatives incorporating a benzimidazole group were innovatively designed, synthesized, and evaluated for their efficacy against fungal pathogens. The bioassay results revealed that the EC50 values for the compounds A7 (3-(difluoromethyl)-1-methyl-N-(1-propyl-1H-benzo[d]imidazol-2-yl)-1H-pyrazole-4-carboxamide) and B11 (N-(1-(4-chlorobenzyl)-1H-benzo[d]imidazol-2-yl)-3-(difluoromethyl)-1-methyl-1H-pyrazole-4-carboxamide) against B. cinerea were notably low to 0.79 µg/mL and 0.56 µg/mL, respectively, demonstrating the potency comparable to that of the control fungicide boscalid, which has an EC50 value of 0.60 µg/mL. Noteworthy is the fact that in vivo tests demonstrated that A7 and B11 showed superior protective effects on tomatoes and strawberries against B. cinerea infection when juxtaposed with the commercial fungicide carbendazim. The examination through scanning electron microscopy revealed that B11 notably alters the morphology of the fungal mycelium, inducing shrinkage and roughening of the hyphal surfaces. To elucidate the mechanism of action, the study on molecular docking and molecular dynamics simulations was conducted, which suggested that B11 effectively interacts with crucial amino acid residues within the active site of succinate dehydrogenase (SDH). This investigation contributes a novel perspective for the structural design and diversification of potential SDH inhibitors, offering a promising avenue for the development of antifungal therapeutics.