Pharmacological significance of heterocyclic 1H-benzimidazole scaffolds: a review

Synthesis and Photophysical Characterizations of Benzimidazole Functionalized BODIPY Dyes

Herein, a series of new BODIPY dyes substituted by 2-phenyl benzimidazole units at the meso (C8) position including methyl/ethyl, phenyl, or p-methoxyphenyl moieties at the distal and proximal positions of the BODIPY core have been successfully synthesized and their photophysical characteristics were analyzed. Experimentally investigating absorption and fluorescence profiles in the THF media was followed by density functional theory (DFT) calculations to clarify photophysical features. Theoretical analyses have revealed that upon excitation, both electrons and holes are confined solely within the BODIPY core. The energy levels of the frontier molecular orbitals converge depending on the presence of the phenyl and p-methoxyphenyl substituents. The orbital distributions of both electron and hole were in the -3 and -5 positions, which demonstrates a continuous conjugation with the BODIPY core at these sites. However, the electron density present on the phenyl rings located at the -1, -7, and -8 (meso) positions was found to be negligible. The benzimidazole-BODIPYs exhibited photodynamic activity (Φ∆) ranging from ~ 7% to ~ 11%, determined by a comparative method. Moreover, the compounds have shown to maintain their stability thermally in a non-reactive/inert environment up to temperatures surpassing 300 °C, exhibiting primarily a two-phase decomposition process. These compounds have the potential to function as antibacterial and anti-biofilm agents when used in concentrations ranging from 0.5 to 2.0 mg/mL. The results provide a basis for evaluating heterocyclic benzimidazole units on photophysical processes containing BODIPY chromophores.

Gold Nanoparticles Functionalized With 5-Amino-2-Mercaptobenzimidazole: A Promising Antimicrobial Strategy Against Carbapenem-Resistant Gram-Negative Bacteria

Introduction

Carbapenem-resistant gram-negative bacteria (CR-GNB) pose a significant threat to public health and require immediate attention. The development of novel antibacterial agents against CR-GNB has become an urgent priority, and nanomaterials offer promising solutions due to their unique properties. This study introduces 5-amino-2-mercaptobenzimidazole (5-A-2MBI) functionalized gold nanoparticles (5-A-2MBI_Au NPs) and evaluates their antibacterial activity against CR-GNB.

Methods

The 5-A-2MBI_Au NPs was synthesized using a one-pot method. Its biocompatibility, bactericidal properties, and mechanisms of action were systematically characterized through in vivo and in vitro toxicity tests, antimicrobial susceptibility testing, live/dead staining, membrane permeability and reactive oxygen species (ROS) generation assays, as well as transcriptomic analysis.

Results

The results of this study demonstrate that 5-A-2MBI_Au NPs exhibit excellent antibacterial efficacy against carbapenem-resistant gram-negative bacteria with various resistance mechanisms, with a minimum inhibitory concentration (MIC) of 2 μg/mL. In vivo experiments further confirmed that 5-A-2MBI_Au NPs not only possess effective bactericidal activity but also exhibit satisfactory biocompatibility. Mechanistic studies revealed that 5-A-2MBI_Au NPs enhance bacterial membrane permeability, increase the generation of reactive oxygen species, and disrupt intracellular oxidative stress and succinate synthesis, thereby conferring potent antibacterial activity. This study results demonstrate that 5-A-2MBI_Au NPs exhibit notable antibacterial efficacy against CR-GNB, with a minimum inhibitory concentration of 2 μg/mL. The antibacterial mechanism involves enhanced membrane permeability, increased reactive oxygen species production, and interference with intracellular oxidative stress and succinate synthesis. These mechanisms collectively contribute to the potent antibacterial activity of 5-A-2MBI_Au NPs against CR-GNB.

Discussion

5-A-2MBI_Au NPs are a novel and highly effective antibacterial agent prepared through a simple process using benzimidazole and HAuCl4•3H2O. They efficiently eradicate the most challenging multidrug-resistant GNB both in vitro and in vivo while demonstrating excellent biocompatibility. This highlights their potential as a promising antibacterial agent to combat multidrug-resistant GNB.

Emerging Role of Natural Topoisomerase Inhibitors as Anticancer agents

Topoisomerases I and II are the functionally two forms of DNA topoisomerase. In anticancer research, novel anticancer chemotherapeutical capable of blocking topoisomerase enzymes have been discovered. Most commonly, topoisomerase causes replication fork arrest and doublestrand breaks, and this is how a clinically successful topoisomerase-targeting anticancer medicines work. Unfortunately, this novel mechanism of action has been linked to the development of secondary malignancies as well as cardiotoxicity. The specific binding locations and mechanisms of topoisomerase poisons have been identified by studying the structures of topoisomerase-drug-DNA ternary complexes. Recent breakthroughs in science have revealed that isoform-specific human topoisomerase II poison could be created as safer anticancer drug molecules. It may also be able to develop catalytic inhibitors of topoisomerases by focusing on their inactive conformations. In addition to this, the discovery of new bacterial topoisomerase inhibitor molecules and regulatory proteins could lead to the discovery of new human topoisomerase inhibitors. As a result, biologists, organic chemists, and medicinal chemists worldwide have been identifying, designing, synthesizing, and testing a variety of novel topoisomerase-targeting bioactive compounds. This review focused on topoisomerase inhibitors, their mechanisms of action, and different types of topoisomerase inhibitors that have been developed during the last ten years.

Facile Synthesis and Applications of Flavonoid-Heterocyclic Derivatives

Flavonoids belong to the polyphenol group that naturally exists in fruits, vegetables, tea, and grains. Flavonoids, as secondary metabolites, show indispensable contributions to biological processes and the responses of plants to numerous environmental factors. The bioactivity of flavonoids depends on C6-C3-C6 ring substitution patterns that exhibit bioactive antioxidant, antimicrobial, antifungal, antitumor, and anti-inflammatory properties. The synthesis of flavonoids has been reported by various methodologies. Therefore, the present review systematically summarizes the synthesis of recent heterocyclic flavonoid derivatives via facile synthetic approaches since the research in flavonoids is useful for therapeutic and biotechnology fields.

Investigation of photoluminescence and DNA binding properties of benzimidazole compounds containing benzophenone group

The synthesis of benzimidazole compounds containing benzophenone group in accordance with the literature and the investigation of DNA binding properties of these compounds by using UV-vis and photoluminescence spectroscopy methods constitute the basis of this research. The structures of the compounds were determined by methods such as FT-IR, 1H, 13C NMR, UV-vis, Photoluminescence spectroscopy, and X-ray crystallography. By using methods such as UV-vis, Photoluminescence spectroscopy, and viscosity tests, information were collected about the binding types, binding mode, and binding energies of the compounds with DNA. In addition, the binding interactions of the compounds with DNA were investigated using the molecular docking technique. Using this information, calibration equations, correlation coefficients (r2), and DNA binding constants (Kb) were calculated for their compounds. The binding constants (Kb) calculated for substances A, B, and C were found to be 3.0 × 104, 7.0 × 104, and 3.0 × 104 M-1, respectively. UV-vis, EB competitive binding, and viscosity tests showed that the compounds tended to bind to the DNA structure via the groove binding mode. At the end of molecular docking studies, it was determined that compound B showed the best DNA binding activity in in vitro studies. Compared with the studies in the literature, it is thought that the synthesized compounds can take place in cancer drug research as DNA binding agents.Communicated by Ramaswamy H. Sarma.

Design, Synthesis, DFT, docking Studies, and antimicrobial evaluation of novel benzimidazole containing sulphonamide derivatives

In silico approaches have been employed to design a new series of benzimidazole-containing sulphonamide derivatives and qualified compounds have been synthesized to analyze their potential as antimicrobial agents. Antibacterial screening of all synthesized compounds was done using the broth microdilution method against several human pathogenic bacteria, viz. Gram-positive bacteria [B. cerus (NCIN-2156), B. subtilis (ATCC-6051), S. aureus (NCIM-2079)] and Gram-negative bacteria [P. aeruginosa (NCIM-2036), E. coli (NCIM-2065), and a drug-resistant strain of E. coli (U-621)], and the compounds presented admirable MIC values, ranging between 100-1.56 µg/mL. The combinatorial analysis showed the magnificent inhibitory efficiency of the tested compounds, acquired equipotent to ten-fold more potency compared to original MIC values. An immense synergistic effect was exhibited by the compounds during combination studies with reference drugs chloramphenicol and sulfamethoxazole was presented as fractional inhibitory concentration (∑FIC). Enzyme inhibition studies of all synthesized compounds were done by using peptidyl transferase and dihydropteroate synthase enzymes isolated from E. coli and S. aureus and each of the compound presented the admirable IC50 values, where the lead compound 3 bound to peptidyl transferase (of S. aureus with IC50 363.51 ± 2.54 µM and E. coli IC50 1.04 ± 0.08 µM) & dihydropteroate synthase (of S. aureus IC50 3.51 ± 0.82 µM and E. coli IC50 2.77 ± 0.65 µM), might account for the antimicrobial effect, exhibited excellent inhibition potential. Antifungal screening was also performed employing food poisoning methods against several pathogenic fungal species, viz A. flavus, F. oxysporum, A. niger, and A. brassicae. The obtained result indicated that few compounds can prove to be a potent drug regimen against dreaded MDR strains of microbes. Structural activity relationship (SAR) analysis and docking studies reveal that the presence of electron-withdrawing, polar, and more lipophilic substituents positively favor the antibacterial activity, whereas, electron-withdrawing, more polar, and hydrophilic substituents favor the antifungal activities. A robust coherence has been found in in-silico and in-vitro biological screening results of the compounds.

Visible-Light-Activated Heteroaryl Azoswitches: Toward a More Colorful Future

Azobenzenes (Ph-N═N-Ph) are known as the most widely studied molecular photoswitches, and the recent rise of azoheteroarenes (Het-N═N-Ph or Het-N═N-Het) offers great opportunities to advance this already mature field. A common limitation is that azo-switches generally require harmful UV light for activation, which hinders their application across various fields. Despite great efforts in developing visible-light azobenzenes over the past few decades, the potential of visible-light heteroaryl azoswitches remains largely unexplored. This Perspective summarizes the state-of-the-art advancements in visible-light heteroaryl azoswitches, covering molecular design strategies, the structure-property relationship, and potential applications. We highlight the distinctive advantages of azoheteroarenes over azobenzenes in the research and development of visible-light switches. Furthermore, we discuss the opportunities and challenges in this emerging field and propose potential solutions to address crucial issues such as spectral red-shift and thermal half-life. Through this Perspective paper, we aim to provide inspiration for further exploration in this field, in anticipation of the growing prosperity and bright future of visible-light azoheteroarene photoswitches.

A comprehensive review on the progress and challenges of tetrahydroisoquinoline derivatives as a promising therapeutic agent to treat Alzheimer's disease

Alzheimer's disease (AD) is the most common and irreversible neurodegenerative disorder worldwide. While the precise mechanism behind this rapid progression and multifaceted disease remains unknown, the numerous drawbacks of the available therapies are prevalent, necessitating effective alternative treatment methods. In view of the rising demand for effective AD treatment, numerous reports have shown that tetrahydroisoquinoline (THIQ) is a valuable scaffold in various clinical medicinal molecules and has a promising potential as a therapeutic agent in treating AD due to its significant neuroprotective, anti-inflammatory, and antioxidative properties via several mechanisms that target the altered signaling pathways. Therefore, this review comprehensively outlines the potential application of THIQ derivatives in AD treatment and the challenges in imparting the action of these prospective therapeutic agents. The review emphasizes a number of THIQ derivatives, including Dauricine, jatrorrhizine, 1MeTIQ, and THICAPA, that have been incorporated in AD studies in recent years. Subsequently, a dedicated section of the review briefly discusses the emerging potential benefits of multi-target therapeutics, which lie in their ability to be integrated with alternative therapeutics. Eventually, this review elaborates on the rising challenges and future recommendations for the development of therapeutic drug agents to treat AD effectively. In essence, the valuable research insights of THIQ derivatives presented in this comprehensive review would serve as an integral reference for future studies to develop potent therapeutic drugs for AD research.

Innovative Arylimidazole-Fused Phytovirucides via Carbene-Catalyzed [3+4] Cycloaddition: Locking Viral Cell-To-Cell Movement by Out-Competing Virus Capsid-Host Interactions

The control of potato virus Y (PVY) induced crop failure is a challengeable issue in agricultural chemistry. Although many anti-PVY agents are designed to focus on the functionally important coat protein (CP) of virus, how these drugs act on CP to inactivate viral pathogenicity, remains largely unknown. Herein, a PVY CP inhibitor -3j (S) is disclosed, which is accessed by developing unusually efficient (up to 99% yield) and chemo-selective (> 99:1 er in most cases) carbene-catalyzed [3+4] cycloaddition reactions. Compound -3j bears a unique arylimidazole-fused diazepine skeleton and shows chirality-preferred performance against PVY. In addition, -3j (S) as a mediator allows ARG191 (R191) of CP to be identified as a key amino acid site responsible for intercellular movement of virions. R191 is further demonstrated to be critical for the interaction between PVY CP and the plant functional protein NtCPIP, enabling virions to cross plasmodesmata. This key step can be significantly inhibited through bonding with the -3j (S) to further impair pathogenic behaviors involving systemic infection and particle assembly. The study reveals the in-depth mechanism of action of antiviral agents targeting PVY CP, and contributes to new drug structures and synthetic strategies for PVY management.

Arylazobenzimidazoles: versatile visible-light photoswitches with tuneable Z-isomer stability

Benzimidazole heterocycles are of great importance in medicinal chemistry due to their applicability to a wide range of pharmacological targets, therefore representing a prototypical "privileged structure". In photopharmacology, azoheteroarene photoswitches have emerged as valuable tools for a variety of applications due to the high tuneability of their photophysical properties. Benzimidazole-based photoswitches could therefore enable the optically-controlled investigation of many pharmacological targets and find application in materials science. Here we report a combined experimental and computational investigation of such arylazobenzimidazoles, which allowed us to identify derivatives with near-quantitative bidirectional photoswitching using visible light and highly tuneable Z-isomer stability. We further demonstrate that arylazobenzimidazoles bearing a free benzimidazole N-H group not only exhibit efficient bidirectional photoswitching, but also excellent thermal Z-isomer stability, contrary to previously reported fast-relaxing Z-isomers of N-H azoheteroarenes. Finally, we describe derivatives which can be reversibly isomerized with cyan and red light, thereby enabling significantly "red-shifted" photocontrol over prior azoheteroarenes. The understanding gained in this study should enable future photopharmacological efforts by employing photoswitches based on the privileged benzimidazole structure.

State-of-the-art Review on the Antiparasitic Activity of Benzimidazolebased Derivatives: Facing Malaria, Leishmaniasis, and Trypanosomiasis

Protozoan parasites represent a significant risk for public health worldwide, afflicting particularly people in more vulnerable categories and cause large morbidity and heavy economic impact. Traditional drugs are limited by their toxicity, low efficacy, route of administration, and cost, reflecting their low priority in global health management. Moreover, the drug resistance phenomenon threatens the positive therapy outcome. This scenario claims the need of addressing more adequate therapies. Among the diverse strategies implemented, the medicinal chemistry efforts have also focused their attention on the benzimidazole nucleus as a promising pharmacophore for the generation of new drug candidates. Hence, the present review provides a global insight into recent progress in benzimidazole-based derivatives drug discovery against important protozoan diseases, such as malaria, leishmaniasis and trypanosomiasis. The more relevant chemical features and structure-activity relationship studies of these molecules are discussed for the purpose of paving the way towards the development of more viable drugs for the treatment of these parasitic infections.

Nitrogen-fused Heterocycles: Empowering Anticancer Drug Discovery

The worldwide impact of cancer is further compounded by the constraints of current anticancer medications, which frequently exhibit a lack of selectivity, raise safety apprehensions, result in significant adverse reactions, and encounter resistance mechanisms. The current situation highlights the pressing need to develop novel and more precise anticancer agents that prioritize safety and target specificity. Remarkably, more than 85% of drugs with physiological activity contain heterocyclic structures or at least one heteroatom. Nitrogen-containing heterocycles hold a significant position among these compounds, emerging as the most prevalent framework within the realm of heterocyclic chemistry. This article explores the medicinal chemistry behind these molecules, highlighting their potential as game-changing possibilities for anticancer medication development. The analysis highlights the inherent structural variety in nitrogen-containing heterocycles, revealing their potential to be customized for creating personalized anticancer medications. It also emphasizes the importance of computational techniques and studies on the relationships between structure and activity, providing a road map for rational medication design and optimization. Nitrogen- containing heterocycles are a promising new area of study in the fight against cancer, and this review summarises the state of the field so far. By utilizing their inherent characteristics and exploiting cooperative scientific investigations, these heterocyclic substances exhibit potential at the forefront of pioneering therapeutic approaches in combating the multifaceted obstacles posed by cancer.

Hybrids of Benzimidazole-oxadiazole: A New Avenue for Synthesis, Pharmacological Activity and Recent Patents for the Development of More Effective Ligands

BACKGROUND

Two significant families of compounds i.e. 1,3,4-oxadiazole and benzimidazole, have undergone extensive investigation into their pharmacological characteristics and possible therapeutic applications. Both classes have shown their potential in a variety of applications, and because of their synergistic interactions, they may have an even better therapeutic impact when combined.

OBJECTIVES

To produce a specific molecule with potent therapeutic properties, it is now common methods to combine at least two pharmacophores. This facilitates interaction with several targets, enhances biological functions, or eliminates adverse effects associated with them.

CONCLUSION

The synthesis of benzimidazole-1,3,4-oxadiazole hybrid compounds has recently involved the use of several synthetic techniques, all of which are detailed in the literature along with the advantages and disadvantages. It has been noted that the structure-activity relationship relates their pharmacological actions to their molecular structure. In order to set the stage for future research, the study aims to provide researchers with an effective toolbox and an understanding of benzimidazole and 1,3,4-oxadiazole hybrid compounds.

Design, synthesis, and anti-respiratory syncytial virus potential of novel 3-(1,2,3-triazol-1-yl)furoxazine-fused benzimidazole derivatives

Respiratory syncytial virus (RSV) is a major cause of serious lower respiratory tract infections in infants, children, and older persons. Currently, the only approved anti-viral chemotherapeutic drug for RSV treatment is ribavirin aerosol; however, its significant toxicity has led to restricted clinical use. In a previous study, we developed various benzimidazole derivatives against RSV. In this study, we synthesised 3-azide substituted furoxazine-fused benzimidazole derivatives by sulfonylation and azide substitution of the 3-hydroxyl group of the furoxazine-fused benzimidazole derivatives. Subsequently, a series of 3-(1,2,3-triazol-1-yl)-substituted furoxazine-fused benzimidazole derivatives were synthesised using the classical click reaction. Biological evaluations of the target compounds indicated that compound 4a-2 had higher activity against RSV (EC50 = 12.17 μM) and lower cytotoxicity (CC50 = 390.64 μM). Compound 4a-2 exerted anti-viral effects against the RSV Long strain by inhibiting apoptosis and the elevation of reactive oxygen species (ROS) and inflammatory factors caused by viral infection in vitro. Additionally, the clinical symptoms of the virus-infected mice were markedly relieved, and the viral load in the lung tissues was dramatically decreased. The biosafety profile of compound 4a-2 was also favourable, showing no detectable adverse effects on any of the major organs in vivo. These findings underscore the potential of compound 4a-2 as a valuable therapeutic option for combating RSV infections while also laying the foundation for further research and development in the field.

Visible-Light Photoswitchable Benzimidazole Azo-Arenes as β-Arrestin2-Biased Selective Cannabinoid 2 Receptor Agonists

The cannabinoid 2 receptor (CB2 R) has high therapeutic potential for multiple pathogenic processes, such as neuroinflammation. Pathway-selective ligands are needed to overcome the lack of clinical success and to elucidate correlations between pathways and their respective therapeutic effects. Herein, we report the design and synthesis of a photoswitchable scaffold based on the privileged structure of benzimidazole and its application as a functionally selective CB2 R "efficacy-switch". Benzimidazole azo-arenes offer huge potential for the broad extension of photopharmacology to a wide range of optically addressable biological targets. We used this scaffold to develop compound 10 d, a "trans-on" agonist, which serves as a molecular probe to study the β-arrestin2 (βarr2) pathway at CB2 R. βΑrr2 bias was observed in CB2 R internalization and βarr2 recruitment, while no activation occurred when looking at Gα16 or mini-Gαi . Overall, compound 10 d is the first light-dependent functionally selective agonist to investigate the complex mechanisms of CB2 R-βarr2 dependent endocytosis.

Seleno/Thio-functionalized ipso-Annulation of N-Propiolyl-2-arylbenzimidazole to Construct Azaspiro[5,5]undecatrienones

Till date, the ipso-cyclization of propiolamides is limited to provide azaspiro[4,5]decatrienones. Herein, we present the first example of ipso-carbocyclization, leading to azaspiro[5,5]-undecatrienones from N-propiolyl-2-arylbenzimidazoles, involving both the radical-based and electrophilic reactions. This report establishes an access to a wide range of chalcogenated (SCN/SCF3/SePh) benzimidazo-fused azaspiro[5,5]undecatrienones in good yields.

Unexpected structural complexity of d-block metallosupramolecular architectures within the benzimidazole-phenoxo ligand scaffold for crystal engineering aspects

Design of metallosupramolecular materials encompassing more than one kind of supramolecular interaction can become deceptive, but it is necessary to better understand the concept of the controlled formation of supramolecular systems. Herein, we show the structural diversity of the bis-compartmental phenoxo-benzimidazole ligand H3L1 upon self-assembly with variety of d-block metal ions, accounting for factors such as: counterions, pH, solvent and reaction conditions. Solid-state and solution studies show that the parent ligand can accommodate different forms, related to (de)protonation and proton-transfer, resulting in the formation of mono-, bi- or tetrametallic architectures, which was also confirmed with control studies on the new mono-compartmental phenoxo-benzimidazole H2L2 ligand analogue. For the chosen architectures, structural variables such as porous character, magnetic behaviour or luminescence studies were studied to demonstrate how the form of H3L1 ligand affects the final form of the supramolecular architecture and observed properties. Such complex structural variations within the benzimidazole-phenoxo-type ligand have been demonstrated for the first time and this proof-of-concept can be used to integrate these principles in more sophisticated architectures in the future, combining both the benzimidazole and phenoxide subunits. Ultimately, those principles could be utilized for targeted manipulation of properties through molecular tectonics and crystal engineering aspects.

New hybrids based on benzimidazole and diazepine moieties: design, synthesis, characterization, molecular docking studies and their in vitro interactions with benzodiazepine receptors

Benzodiazepines are one of the most widely prescribed pharmacologic agents in the world. They are employed for numerous indications, including anxiety, insomnia, muscle relaxation, relief from spasticity caused by central nervous system pathology and epilepsy. In this work, we have synthesized some new hybrids based on benzimidazole and diazepine scaffolds from the reaction of suitable benzimidazole derivatives with glycine. NMR spectra, IR and mass as well as elemental analyses approved the structure of the title compounds. In vitro interactions of the title compounds were also examined on recombinant benzodiazepine receptors (αxβ2/3γ2, x = 1-3, 5) expressed in HEK293 cells. The results indicated that the title compounds exhibited suitable affinity for α1β2 γ2 subtype (Ki = 16-29 nM). To achieve deeper insight into their interactions with benzodiazepine receptors, molecular dynamics simulation was employed. According to the results obtained from the molecular dynamics simulation, Pro85, Leu103, Pro101, Gln102, Ile79, Ser80, Pro17, Leu82 and Val84 interact with the most potent ligand by hydrophobic interactions and Asp86 and Leu87 interact with the ligand by hydrogen bond interactions.Communicated by Ramaswamy H. Sarma.

Organocatalytic Atroposelective Construction of Axially Chiral Compounds Containing Benzimidazole and Quinoline Rings

An organocatalytic atroposelective strategy for the construction of axially chiral compounds containing benzimidazole and quinoline rings is described. The enantioselective heteroannulation reaction of 2-alkynylbenzimidazoles with ortho-aminophenylketones proceeded smoothly in the presence of chiral phosphoric acid to provide axially chiral heterobiaryls with good yields and enantioselectivities. This is the first example of the combination of benzimidazole and quinoline rings at the 2- and 3-positions, respectively, into axially chiral heterobiaryls by this new strategy.

Anticancer, antioxidant activities and molecular docking study of thiazolidine-4-one and thiadiazol derivatives

Liver cancer accounts for a major portion of the global cancer burden. In many nations, the prevalence of this condition has risen in recent decades. New series of thiazolidinones and thiadiazolidine have been designed, synthesized, and evaluated for potential antioxidant and antihepatocarcinogenic activity. The antioxidant activity was evaluated using a DPPH assay. Furthermore, we examined the compounds against Hepg-2 cells using MTT assay, flow cytometry analysis through the cell cycle, reactive oxygen species, and apoptosis. The result showed that compound 6b has the highest antioxidant activity with IC50 = 60.614 ± 0.739 µM. The anticancer activity showed that compounds 5 and 6b have significant toxicity against liver cancer cells Hepg2, IC50 values (9.082 and 4.712) µM, respectively. Flow cytometry experiments revealed that compound 5 arrested Hepg-2 cells in the S process, while compound 6b arrested Hepg-2 cells in the G1. Compound 6b had a greater reduction in reactive oxygen species and late apoptosis than compound 5. Substantially, compound 5 had affinity energies of -7.6 and -8.5 for Akt and CDK4 proteins, respectively, but compound 6b had affinity energies of -7.8 and -10.1 for Akt1 and CDK4 proteins, respectively. Consequently, compound 6b had lower binding energies than compound 5. In this work, we used multiple bioinformatics methods to shed light on the prospective therapeutic use of these series as novel candidates to target immune cells in the tumor microenvironment of hepatocellular carcinomas such as CD8+ T cells, endothelial cells, and hematopoietic stem cells.

Insights into the structure and drug design of benzimidazole derivatives targeting the epidermal growth factor receptor (EGFR)

Tyrosine kinase overexpression could result in an unfavourable consequence of cancer progression in the body. A number of kinase inhibitor drugs targeting various cancer-related protein kinases have been developed and proven successful in clinical therapy. Benzimidazole is one of the most studied scaffolds in the search for effective anticancer drugs. The association of various functional groups and the structural design of the compounds may influence the binding towards the receptor. Despite numerous publications on the design, synthesis and biological assays of benzimidazole derivatives, their inhibitory activities against epidermal growth factor receptor (EGFR), a receptor tyrosine kinase (RTK), have not been specifically analysed. This review covers recent research reports on the anticancer activity of benzimidazole derivatives focusing on EGFR expression cell lines, based on their structure-activity relationship study. We believe it would aid researchers to envision the challenges and explore benzimidazole's potentials as tyrosine kinase inhibitors.

Deciphering the nature of binding of dexlansoprazole with DNA: Biophysical and docking approaches

Drugs, in general, exhibit their pharmacological activity in binding with intracellular targets. Numerous anticancer and antibacterial drugs target DNA as one of their primary intracellular targets. Dexlansoprazole (DLP) is a heterocyclic compound containing benzimidazole moiety and a proton pump inhibitor used to treat gastroesophageal reflux disease. The interaction of dexlansoprazole with calf thymus DNA (ct-DNA) has been studied using biophysical methods. The UV-Visible studies revealed a binding constant of 2.15 ± 0.3 × 104 M^-1 which is close to the value of 2.44 ± 0.3 × 10⁴ M^-1 obtained from the fluorescence studies. Competitive displacement studies using the fluorescence spectroscopic method with ethidium bromide and Hoechst as DNA markers suggested the groove binding mode of DLP in ct-DNA. The groove binding mode of DLP in ct-DNA was complemented by the results of viscosity and DNA melting studies. Further studies on the effect of ionic strength and potassium iodide on DLP binding with ct-DNA supported the observed binding mode. Circular dichroism studies reflected no significant conformational variation in ct-DNA after the interaction. The binding mode obtained from the experimental studies was corroborated by the molecular docking studies that showed the position of DLP in the minor groove of ct-DNA along with the receptor interface restudies involved in the interaction.

Structure-Activity Relationship of New Chimeric Analogs of Mastoparan from the Wasp Venom Paravespula lewisii

Mastoparan (MP) is an antimicrobial cationic tetradecapeptide with the primary structure INLKALAALAKKIL-NH₂. This amphiphilic α-helical peptide was originally isolated from the venom of the wasp Paravespula lewisii. MP shows a variety of biological activities, such as inhibition of the growth of Gram-positive and Gram-negative bacteria, as well as hemolytic activity and activation of mast cell degranulation. Although MP appears to be toxic, studies have shown that its analogs have a potential therapeutic application as antimicrobial, antiviral and antitumor agents. In the present study we have designed and synthesized several new chimeric mastoparan analogs composed of MP and other biologically active peptides such as galanin, RNA III inhibiting peptide (RIP) or carrying benzimidazole derivatives attached to the ε-amino side group of Lys residue. Next, we compared their antimicrobial activity against three reference bacterial strains and conformational changes induced by membrane-mimic environments using circular dichroism (CD) spectroscopy. A comparative analysis of the relationship between the activity of peptides and the structure, as well as the calculated physicochemical parameters was also carried out. As a result of our structure-activity study, we have found two analogs of MP, MP-RIP and RIP-MP, with interesting properties. These two analogs exhibited a relatively high antibacterial activity against S. aureus compared to the other MP analogs, making them a potentially attractive target for further studies. Moreover, a comparative analysis of the relationship between peptide activity and structure, as well as the calculated physicochemical parameters, may provide information that may be useful in the design of new MP analogs.

Seeking heterocyclic scaffolds as antivirals against dengue virus

Dengue is one of the most typical viral infection categorized in the Neglected Tropical Diseases (NTDs). It is transmitted via the female Aedes aegypti mosquito to humans and majorly puts risk to the lives of more than half of the world. Recent advancements in medicinal chemistry have led to the design and development of numerous potential heterocyclic scaffolds as antiviral drug candidates for the inhibition of the dengue virus (DENV). Thus, in this review, we have discussed the significance of inhibitory and antiviral activities of nitrogen, oxygen, and mixed (nitrogen-sulfur and nitrogen-oxygen) heterocyclic scaffolds that are published in the last seven years (2016–2022). Furthermore, we have also discussed the probable mechanisms of action and the diverse structure-activity relationships (SARs) of the heterocyclic scaffolds. In addition, this review has elaborately outlined the mechanism of viral infection and the life cycle of DENV in the host cells. The wide set of heterocycles and their SARs will aid in the development of pharmaceuticals that will allow the researchers to synthesize the promising anti-dengue drug candidate in the future.

Physicochemical Properties of a Bi-aromatic Heterocyclic-Azo/BSA Hybrid System at the Air-Water Interface

The interaction of a heterocyclic azo compound with itself and with bovine serum albumin (BSA) is realized by probing the structural modifications in Langmuir (L) monolayers and Langmuir-Blodgett (LB) films. It was found from the pressure-area/molecule isotherms that the elastic, thermodynamic, and hysteretic properties of the pure azo L monolayer were strongly altered due to the variation of temperature and pH of subphase water. In addition to that, the modification of such properties of the azo L monolayer due to mixing with BSA was also studied. The incorporation of BSA within the azo molecular assembly reduced the elasticity of that assembly. Such reduction of in-plane elasticity of the pure azo monolayer can also be achieved by reducing the temperature and pH of subphase water without adding BSA. A reduction in area per molecule of the azo assembly at the air-water interface associated with the conformational change from horizontal to vertical orientation facilitating π-π interaction was observed with increase in temperature and pH of the subphase. Such parameters also affected the interactions between azo and BSA molecules within the azo/BSA binary system. The structures of pure azo and binary films can be determined after they are transferred to hydrophilic and hydrophobic Si surfaces using the LB technique. Their out-of-plane and in-plane structures, as extracted from two complementary surface sensitive techniques, X-ray reflectivity and atomic force microscopy, were found to be strongly dependent on mixing with BSA, subphase pH, temperature, and substrate nature.

Synthesis of Benzimidazole-Sulfonyl Derivatives and Their Biological Activities

Currently, the synthesis of new compounds with potential bioactivities has become a central issue in the drug discovery arena. Among these new compounds, benzimidazole-sulfonyl scaffolds have vital applications in the fields of pharmaceuticals industries. Benzimidazole and sulfonyl compounds have remarkable biological activities, such as antibacterial, antifungal, anti-inflammatory, antiproliferative, carbonic anhydrase inhibitory, and α-amylase inhibitory activities. Furthermore, recent literature mentions the synthesis and bioactivities of some benzimidazole-sulfonyl hybrids. In this review, we focus on reviewing the synthesis of these hybrid scaffolds and their various types of biological activities of the compounds.

Molecularly Engineering Defective Basal Planes in Molybdenum Sulfide for the Direct Synthesis of Benzimidazoles by Reductive Coupling of Dinitroarenes with Aldehydes

Developing more sustainable catalytic processes for preparing N-heterocyclic compounds in a less costly, compact, and greener manner from cheap and readily available reagents is highly desirable in modern synthetic chemistry. Herein, we report a straightforward synthesis of benzimidazoles by reductive coupling of o-dinitroarenes with aldehydes in the presence of molecular hydrogen. An innovative molecular cluster-based synthetic strategy that employs Mo₃S₄ complexes as precursors have been used to engineer a sulfur-deficient molybdenum disulfide (MoS₂)-type material displaying structural defects on both the naturally occurring edge positions and along the typically inactive basal planes. By applying this catalyst, a broad range of functionalized 2-substituted benzimidazoles, including bioactive compounds, can be selectively synthesized by such a direct hydrogenative coupling protocol even in the presence of hydrogenation-sensitive functional groups, such as double and triple carbon-carbon bonds, nitrile and ester groups, and halogens as well as diverse types of heteroarenes.

Coumarin-benzimidazole hybrids: A review of developments in medicinal chemistry

Coumarin and benzimidazole are privileged structures in medicinal chemistry and are widely used in drug discovery and development due to their vast biological properties. The pharmacokinetic and pharmacodynamic properties of the individual scaffolds can be improved by developing coumarin-benzimidazole chimeric molecules via molecular hybridization approach. The three major classes of coumarin-benzimidazole hybrids are merged, fused and spacer-linked hybrids. Depending on the substitution position, fused hybrids and spacer-linked hybrids can be further classified as coumarin-C3 hybrids, coumarin-C4 hybrids and coumarin-C5/6/7/8 hybrids. Most of the coumarin-benzimidazole hybrid molecules exhibited potent anticancer, antiviral, antimicrobial, antitubercular, anthelmintic, anti-inflammatory, antioxidant, anticonvulsant and carbonic anhydrase inhibitory activities. The fused coumarin-C3 hybrid (2), thiomethylene-linked coumarin-C3 hybrid (45), N-glucoside substituted thiomethylene-linked coumarin-C3 hybrid (37c), amide-linked coumarin-C3 hybrid (50a), and sulfonylmethylene-linked coumarin-C4 hybrid (63) were identified as the representative potent anticancer, antimicrobial, antiviral, antioxidant and antitubercular agents respectively. The biological properties of the different classes of coumarin-benzimidazole hybrids with their structure-activity relationship studies and the mechanism of action studies were presented in this review, aiming to help the researchers across the globe to generate future hybrid molecules as potential drug candidates.

Formulating The Structural Aspects Of Various Benzimidazole Cognates

BACKGROUND

Benzimidazole derivatives are widely used in clinical practice as potential beneficial specialists. Recently, the neuroprotective effect of derivatives of benzimidazole moiety has also shown positive outcomes.

OBJECTIVE

To develop favourable molecules for various neurodegenerative disorders using the versatile chemical behaviour of the benzimidazole scaffold.

METHODS

About 25 articles were collected that discussed various benzimidazole derivatives and categorized them under various subheadings based on the targets such as BACE 1, JNK, MAO, choline esterase enzyme, oxidative stress, mitochondrial dysfunction in which they act. The structural aspects of various benzimidazole derivatives were also studied.

CONCLUSION

To manage various neurodegenerative disorders, a multitargeted approach will be the most hopeful stratagem. Some benzimidazole derivatives can be considered for future studies, which are mentioned in the discussed articles.

2,2′-(1,4-Phenylene)bis(7-nitro-1H-benzimidazole 3-oxide)

Bis(benzimidazol-2-yl-3-oxide)benzene derivatives have potential applications as energetic or photoactive materials. By using a two-step one-pot approach employing microwave heating as a tool, 2,2′-(1,4-phenylene)bis(7-nitro-1H-benzimidazole 3-oxide) (1) has been prepared in 94% yield. In the first step an SNAr reaction is performed using p-xylylenediamine as the central building block. Without isolating the intermediate, a base-mediated cyclization reaction follows in the second step. The product was isolated in analytically pure form by means of a pH-controlled precipitation.

Metal-Free Synthesis of Heteroaryl Amines or Their Hydrochlorides via an External-Base-Free and Solvent-Free C-N Coupling Protocol

Herein, a metal-free and solvent-free protocol was developed for the C-N coupling of heteroaryl halides and amines, which afforded numerous heteroaryl amines or their hydrochlorides without any external base. Further investigations elucidated that the basicity of amines and specific interactions derived from the X-ray crystallography analysis of 3j'·HCl played pivotal roles in the reactions. Moreover, this protocol was scalable to gram scales and applicable to drug molecules, which demonstrated its practical value for further applications.

A Comprehensive Account on Recent Progress in Pharmacological Activities of Benzimidazole Derivatives

Nowadays, nitrogenous heterocyclic molecules have attracted a great deal of interest among medicinal chemists. Among these potential heterocyclic drugs, benzimidazole scaffolds are considerably prevalent. Due to their isostructural pharmacophore of naturally occurring active biomolecules, benzimidazole derivatives have significant importance as chemotherapeutic agents in diverse clinical conditions. Researchers have synthesized plenty of benzimidazole derivatives in the last decades, amidst a large share of these compounds exerted excellent bioactivity against many ailments with outstanding bioavailability, safety, and stability profiles. In this comprehensive review, we have summarized the bioactivity of the benzimidazole derivatives reported in recent literature (2012-2021) with their available structure-activity relationship. Compounds bearing benzimidazole nucleus possess broad-spectrum pharmacological properties ranging from common antibacterial effects to the world's most virulent diseases. Several promising therapeutic candidates are undergoing human trials, and some of these are going to be approved for clinical use. However, notable challenges, such as drug resistance, costly and tedious synthetic methods, little structural information of receptors, lack of advanced software, and so on, are still viable to be overcome for further research.

Visible-light-mediated one-pot efficient synthesis of 1-aryl-1H,3H-thiazolo[3,4-a]benzimidazoles: a metal-free photochemical approach in aqueous ethanol

A new metal-free approach to construct medicinally valuable 1-aryl-1H,3H-thiazolo[3,4-a]benzimidazoles under visible light irradiation in aqueous ethanol medium at room temperature has been developed. The present process was performed with 1,2-phenylenediamines, aromatic aldehydes and 2-mercaptoacetic acid utilizing a simple household 22 W compact fluorescent lamp to generate C-S, C-N bonds through radical intermediates. This visible-light-promoted synthesis provides lower cost, operation simplicity and high functional groups tolerating ability with short reaction time and high yield under mild reaction conditions.

Design, synthesis, kinetic, molecular dynamics, and hypoglycemic effect characterization of new and potential selective benzimidazole derivatives as Protein Tyrosine Phosphatase 1B inhibitors

Protein-tyrosine phosphatase 1B (PTP1B) is a negative regulator of insulin signaling pathway and has been validated as a therapeutic target for type 2 diabetes. A wide variety of scaffolds have been included in the structure of PTP1B inhibitors, one of them is the benzimidazole nucleus. Here, we report the design and synthesis of a new series of di- and tri- substituted benzimidazole derivatives including their kinetic and structural characterization as PTP1B inhibitors and hypoglycemic activity. Results show that compounds 43, 44, 45, and 46 are complete mixed type inhibitors with a Ki of 12.6 μM for the most potent (46). SAR type analysis indicates that a chloro substituent at position 6(5), a β-naphthyloxy at position 5(6), and a p-benzoic acid attached to the linker 2-thioacetamido at position 2 of the benzimidazole nucleus, was the best combination for PTP1B inhibition and hypoglycemic activity. In addition, molecular dynamics studies suggest that these compounds could be potential selective inhibitors from other PTPs such as its closest homologous TCPTP, SHP-1, SHP-2 and CDC25B. Therefore, the compounds reported here are good hits that provide structural, kinetic, and biological information that can be used to develop novel and selective PTP1B inhibitors based on benzimidazole scaffold.

Ruthenium Complexes with 2-Pyridin-2-yl-1H-benzimidazole as Potential Antimicrobial Agents: Correlation between Chemical Properties and Anti-Biofilm Effects

Antimicrobial resistance is a growing public health concern that requires urgent action. Biofilm-associated resistance to antimicrobials begins at the attachment phase and increases as the biofilms maturate. Hence, interrupting the initial binding process of bacteria to surfaces is essential to effectively prevent biofilm-associated problems. Herein, we have evaluated the antibacterial and anti-biofilm activities of three ruthenium complexes in different oxidation states with 2-pyridin-2-yl-1H-benzimidazole (L1 = 2,2'-PyBIm): [(η6-p-cymene)RuIIClL1]PF6 (Ru(II) complex), mer-[RuIIICl3(CH3CN)L1]·L1·3H2O (Ru(III) complex), (H2L1)2[RuIIICl4(CH3CN)2]2[RuIVCl4(CH3CN)2]·2Cl·6H2O (Ru(III/IV) complex). The biological activity of the compounds was screened against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa strains. The results indicated that the anti-biofilm activity of the Ru complexes at concentration of 1 mM was better than that of the ligand alone against the P. aeruginosa PAO1. It means that ligand, in combination with ruthenium ion, shows a synergistic effect. The effect of the Ru complexes on cell surface properties was determined by the contact angle and zeta potential values. The electric and physical properties of the microbial surface are useful tools for the examined aggregation phenomenon and disruption of the adhesion. Considering that intermolecular interactions are important and largely define the functions of compounds, we examined interactions in the crystals of the Ru complexes using the Hirshfeld surface analysis.