Benzimidazole: an emerging scaffold for analgesic and anti-inflammatory agents

The effects of benzimidazole and electrical stimulation on peripheral nerve regeneration after short- and long-term injury

This research investigated the effects of benzimidazole (BZ) and electrical stimulation (ES) on peripheral nerve regeneration after short- and long-term injury and assessed functional recovery by means of stereological, histological, and electrophysiological analyses. Fifty-four male albino Wistar rats were divided into nine groups of six animals each. No treatment or surgery was applied to the control (CONT) group. The sciatic nerve was crushed for 5 s in the short-term injury (STI) and for 60 s in the long-term injury (LTI) groups. In the STI + BZ group and the LTI + BZ group, the rats received 25 mg/kg/day of BZ via oral gavage for 28 days. In the STI + ES and LTI + ES groups, a 3-V current was applied for 20 min daily for 28 days. In the STI + BZ + ES group and the LTI + BZ + ES groups, 3-V ES was applied for 20 min per day for 28 days following oral administration of BZ at 25 mg/kg/day for 28 days. All groups were subjected to electrophysiological, electron microscopic, stereological, and statistical analyses. The stereological analyses revealed a significant increases in the numbers of myelinated axons in the STI + ES groups compared with the STI (p < 0.01). BZ treatment yielded no significant differences in the numbers of myelinated axons in the groups (p > 0.05). Histological evaluation of the STI and LTI groups showed that ES and BZ treatment positively affect the histological structure of the nerve.

Synthesis and crystal structure analysis of 1-ethyl-1,3-di-hydro-2H-benzo[d]imidazole-2-thione

The asymmetric unit of the title compound, C9H10N2S, contains two crystallographically independent, almost planar, mol-ecules. In the crystal, inter-mole-cular N-H⋯S hydrogen bonds link the mol-ecules into pseudocentrosymmetric dimers, enclosing R 2 2(8) ring motifs. There are mutual π-π inter-actions between the five- and six-membered rings of each independent mol-ecule in the chosen asymmetric unit, with ring centroid-to-centroid distances of 3.6685 (12) and 3.7062 (12) Å. A weak C-H⋯π(ring) inter-action is also observed. The N-H⋯S hydrogen bonds, the π-π inter-actions and the weak C-H⋯π(ring) inter-action are effective in the stabilization of the crystal structure. The structure was refined as an inversion twin with a component occupancy ratio of 0.546 (15):0.454 (16).

An Insight into the Structure-activity Relationship of Benzimidazole and Pyrazole Derivatives as Anticancer Agents

INTRODUCTION

Cancer is a leading cause of death worldwide, driving the urgent need for new and effective treatments. Benzimidazole and pyrazole derivatives have gained attention for their potential as anticancer agents due to their diverse biological activities. The development of resistance in cancer cells, toxicity concerns, and inconsistent efficacy across different types of cancer are a few of the challenges. To overcome these challenges, optimisation of these nuclei using the structure-activity relationships is necessary.

OBJECTIVES

This review aimed to examine various benzimidazole, pyrazole, and their hybrid derivatives by focusing on their structure-activity relationships (SAR) as anticancer agents. Results of the most potent and least potent benzimidazole, pyrazole compounds, and their hybrid derivatives published by researchers were compiled.

METHODS

The findings of different researchers working on benzimidazole and pyrazole nuclei were reviewed and analysed for different targets and cell lines. Moreover, substitutions on different positions of pyrazole, benzimidazole, and their hybrid were summarised to derive an optimised pharmacophore.

RESULTS

Based on our analysis of existing studies, we anticipate that this review will guide researchers in creating potent pyrazole, benzimidazole, and hybrid derivatives crucial for combating cancer effectively.

CONCLUSION

Structure-Activity Relationship (SAR) studies can help in developing pyrazolebenzimidazole hybrids that are more powerful and selective in targeting specific aspects of cancer.

Design, synthesis, biological evaluation, and in silico studies of novel N-substituted-2-(3,4,5-trimethoxyphenyl)-1H-benzo[d]imidazole-6-carboxamides as promising anticancer agents

Novel benzimidazole-based derivatives were synthesized and their cytotoxic activities were evaluated against two human cancer cells, SW480 and A549, and the normal human MRC-5 cells, using the MTT assay. N-(2,4-Dimethoxyphenyl)-2-(3,4,5-trimethoxyphenyl)-1H-benzo[d]imidazole-6-carboxamide (5o) showed excellent cytotoxicity with IC50 values of 0.15 ± 0.01 and 3.68 ± 0.59 μM against A549 and SW480. Compound 5o had 38.5-, 62.9- and 3.1-fold superior cytotoxicity than cisplatin (IC50 = 5.77 ± 1.60 μM), etoposide (IC50 = 9.44 ± 1.98 μM), and doxorubicin (IC50 = 0.46 ± 0.02 μM), respectively against A549 cells. Moreover, 5o exhibited high selectivity towards A549 (SI = 794.6) and SW480 (SI = 32.4) cancer cells compared with the normal MRC-5. Further studies revealed the ability of 5o to induce apoptosis and arrest the cell cycle at the S phase in A549 cells. Molecular docking studies revealed 5o was well accommodated within the pocket of topoisomerase IIα-DNA, as a possible target. Molecular dynamics simulation studies confirmed the stability of the 5o-IIα-DNA complex. Compound 5o was predicted to have appropriate drug-likeness and pharmacokinetic properties.

Development of N-alkylated benzimidazole based cubosome hydrogel for topical treatment of burns

The current study focuses on assessing the activity of the N-alkylated benzimidazole based cubosomal hydrogel (cubogel) for the topical treatment of burn wounds. The study involves the synthesis of six benzimidazole derivatives (1-6) and their characterization by FT-IR and 1H and 13C NMR spectroscopy. The further study involves the design and formation of nanoparticles known as cubosomes loaded with selected 1-benzyl-1-benzimidazole (API 6) and the development of a cubogel for the topical treatment of burn wounds. Cubosomes were prepared by the homogenization method, using glyceryl monooleate (GMO) as a lipid polymer and poloxamer 407 (P407) as a surfactant. Cubosomes undergo in vitro characterizations (measurement of particle size, zeta potential, polydispersity index (PDI), % entrapment efficiency, drug release in phosphate buffer saline of pH 6.8, and surface morphology by utilizing TEM (transmission electron microscopy). Formulation D3 (2.5% of GMO, 1% of P407, and 2.5% of PVA) emerged as the optimized formulation, displaying a minimum particle size (PS) of 129.9 ± 1 nm, entrapment efficiency (%EE) of 96.67 ± 0.89%, and a drug release of 86 ± 2.7% at 24 h. Carbopol 940 hydrogel was prepared and incorporated with the optimized formulation to prepare cubogel. This optimized cubogel provided 92.56 ± 0.014% in vitro drug release within 24 h. An in vivo histopathological study was conducted on an animal model (rabbit) to assess the efficacy of cubogel in wound healing and wound contraction. Then cubogel was compared with the commercially available creams Clotrimazole® and Polyfax®. The wound treated with newly developed cubogel has maximum wound contraction (96.70%) as compared to the standard creams. The findings revealed that the newly formulated cubogel was highly effective in treating burns, showing superior performance to commercial products without inducing side effects. Additionally, benzimidazole derivative loaded cubogel caused a sustained release for treating burn wounds without any bacterial infections. The current results further suggested phase 0 clinical trials.

Synthesis of new two 1,2-disubstituted benzimidazole compounds: their in vitro anticancer and in silico molecular docking studies

In this study, two new molecules were synthesized from the reaction of 2-methyl-1H-benzo[d]imidazole with aryl halides in the presence of a strong base. The structures newly of synthesized 1,2-disubstituted benzimidazole compounds were characterized using spectroscopic techniques (FT-IR, 1HNMR, 13CNMR) and chromatographic technique (LC/MS). For discovering an effective anticancer drug, the developed heterocyclic compounds were screened against three different human cancer cell lines (A549, DLD-1, and L929). The results demonstrated that of IC50 values of compound 2a were higher as compared to cisplatin for the A549 and DLD-1 cell lines. The frontier molecular orbital (FMO), and molecular electrostatic potential map (MEP) analyses were studied by using DFT (density functional theory) calculations at B3LYP/6-31G** level of theory. The molecular docking studies of the synthesized compound with lung cancer protein, PDB ID: 1M17, and colon cancer antigen proteins, PDB ID: 2HQ6 were performed to compare with experimental and theoretical data. Compound 2a had shown the best binding affinity with -6.6 kcal/mol. It was observed that the theoretical and experimental studies carried out supported each other.

Benzimidazole-Oxadiazole Hybrids-Development in Medicinal Chemistry: An Overview

To increase the success rate of drug discovery, one practical strategy is to begin molecular hybridisation. The presence of two or more pharmacophores in a single unit leads to a pharmacological potency greater than the sum of each individual moiety's potency. Heterocyclic compounds are very widely distributed in nature and are essential for life activities. Benzimidazole and oxadiazole are privileged structures in medicinal chemistry and are widely used in drug discovery and development due to their vast biological properties. The drug-like properties (like pharmacokinetics and pharmacodynamics) of the individual scaffolds can be improved by benzimidazole-oxadiazole chimeric molecules via a molecular hybridisation approach. Benzimidazole and oxadiazole cores can either be fused or incorporated using either functional groups/bonds. Over the last few decades, drug discovery scientists have predicted that these moieties could be interconnected to yield a novel or modified hybrid compound. Benzimidazole and oxadiazole hybrids were identified as the most potent anticancer, antimicrobial, anti-inflammatory, antioxidant, anticonvulsant, antidepressant, antihypertensive and antitubercular agents. In this context, the present review describes the biological properties of benzimidazole-oxadiazole (1,3,4 and 1,2,4) hybrids, their possible structure-activity relationship and the mechanism of action studies presented. This review article is intended to stimulate fresh ideas in the search for rational designs of more active and less toxic benzimidazole-oxadiazole hybrid prospective therapeutic candidates, as well as more effective diagnostic agents and pathologic probes.

Synthesis and anti-inflammatory activity of benzimidazole derivatives; an in vitro, in vivo and in silico approach

Many non-steroidal anti-inflammatory drugs (NSAIDs) concurrently inhibit both COX-1 and COX-2, with a preference for specifically targeting COX-2 due to its significant involvement in various pathologies. In addition to COX enzymes, several other targets, including Aldose reductase, Aldo-ketoreductase family 1-member C2, and Phospholipase A2, have been identified as contributors to inflammation and a myriad of other diseases. In this context, a series of 2-substituted benzimidazole derivatives was synthesized and assessed for their anti-inflammatory potential through both in vitro and in vivo assays. Molecular docking studies were conducted to elucidate the mechanism of action of these compounds against COX enzymes and other therapeutic targets associated with NSAIDs, such as Aldose reductase, AIKRC, and Phospholipase A2. Among the synthesized compounds, B2, B4, B7, and B8 demonstrated IC50 values lower than the standard ibuprofen, as determined by the Luminol-enhanced chemiluminescence assay. Validation of these findings was achieved through an in vivo carrageenan-induced mice paw edema model, confirming a comparable anti-inflammatory effect to diclofenac sodium observed in vitro. Notably, these compounds exhibited significant binding affinity with all therapeutic targets investigated in this study. These results suggest that the newly synthesized derivatives possess noteworthy anti-inflammatory potential, warranting further exploration for the development of novel multi-targeting inhibitors.

Synthesis, Anticancer Activity, and In Silico Modeling of Alkylsulfonyl Benzimidazole Derivatives: Unveiling Potent Bcl-2 Inhibitors for Breast Cancer

A series of alkylsulfonyl 1H-benzo[d]imidazole derivatives were synthesized and evaluated for anticancer activity against human breast cancer cells, MCF-7 in vitro. The cytotoxic potential was determined using the xCELLigence real-time cell analysis, and expression levels of genes related to microtubule organization, tumor suppression, apoptosis, cell cycle, and proliferation were examined by quantitative real-time polymerase chain reaction. Molecular docking against Bcl-2 was carried out using AutoDock Vina, while ADME studies were performed to predict the physicochemical and drug-likeness properties of the synthesized compounds. The results revealed that compounds 23 and 27 were the most potent cytotoxic derivatives against MCF-7 cells. Gene expression analysis showed that BCL-2 was the most prominent gene studied. Treatment of MCF-7 cells with compounds 23 and 27 resulted in significant downregulation of the BCL-2 gene, with fold changes of 128 and 256, respectively. Docking analysis predicted a strong interaction between the compounds and the target protein. Interestingly, all of the compounds exhibit a higher binding affinity toward Bcl-2 than the standard drug (compound 27 vina score = -9.6 kcal/mol, vincristine = -6.7 kcal/mol). Molecular dynamics simulations of compounds 23 and 27 showed a permanent stabilization in the binding site of Bcl-2 for 200 ns. Based on Lipinski and Veber's filters, all synthesized compounds displayed drug-like characteristics. These findings suggest that compounds 23 and 27 were the most promising cytotoxic compounds and downregulated the expression of the BCL-2 gene. These derivatives could be further explored as potential candidates for the treatment of breast cancer.

A Critical Review on Therapeutic Potential of Benzimidazole Derivatives: A Privileged Scaffold

Benzimidazole nucleus is a predominant heterocycle displaying a wide spectrum of pharmacological activities. The privileged nature of the benzimidazole scaffold has been revealed by its presence in most small molecule drugs and in its ability to bind multiple receptors with high affinity. A literature review of the scaffold reveals several instances where structural modifications of the benzimidazole core have resulted in high-affinity lead compounds against a variety of biological targets. Hence, this structural moiety offers opportunities to discover novel, better, safe and highly potent biological agents. The goal of the present review is to compile the medicinal properties of benzimidazole derivatives with a focus on SAR (Structure-Activity Relationships).

In silico Approaches for Exploring the Pharmacological Activities of Benzimidazole Derivatives: A Comprehensive Review

BACKGROUND

This article reviews computational research on benzimidazole derivatives. Cytotoxicity for all compounds against cancer cell lines was measured and the results revealed that many compounds exhibited high inhibitions. This research examines the varied pharmacological properties like anticancer, antibacterial, antioxidant, anti-inflammatory and anticonvulsant activities of benzimidazole derivatives. The suggested method summarises In silico research for each activity. This review examines benzimidazole derivative structure-activity relationships and pharmacological effects. In silico investigations can anticipate structural alterations and their effects on these derivative's pharmacological characteristics and efficacy through many computational methods. Molecular docking, molecular dynamics simulations and virtual screening help anticipate pharmacological effects and optimize chemical design. These trials will improve lead optimization, target selection, and ADMET property prediction in drug development. In silico benzimidazole derivative studies will be assessed for gaps and future research. Prospective studies might include empirical verification, pharmacodynamic analysis, and computational methodology improvement.

OBJECTIVES

This review discusses benzimidazole derivative In silico research to understand their specific pharmacological effects. This will help scientists design new drugs and guide future research.

METHODS

Latest, authentic and published reports on various benzimidazole derivatives and their activities are being thoroughly studied and analyzed.

RESULT

The overview of benzimidazole derivatives is more comprehensive, highlighting their structural diversity, synthetic strategies, mechanisms of action, and the computational tools used to study them.

CONCLUSION

In silico studies help to understand the structure-activity relationship (SAR) of benzimidazole derivatives. Through meticulous alterations of substituents, ring modifications, and linker groups, this study identified the structural factors influencing the pharmacological activity of benzimidazole derivatives. These findings enable the rational design and optimization of more potent and selective compounds.

Unlocking the Pharmacological Potential of Benzimidazole Derivatives: A Pathway to Drug Development

Heterocyclic molecules have fascinated a massive interest in medicinal chemistry. They are heterocyclic compounds that have gained significance due to their diverse variety of pharmacological activities. Benzimidazole is a heterocyclic compound consisting of benzene and imidazole rings. The ease of synthesis and the structural versatility of benzimidazole make it a promising scaffold for drug development. Many biological actions of benzimidazole derivatives have been well documented, including antibacterial, antiviral, anticancer, anti-inflammatory, antitubercular, and anthelmintic properties. The mechanism of action of benzimidazole derivatives varies with their chemical structure and target enzyme. This review has explored numerous methods for producing benzimidazole derivatives as well as a broad range of pharmacological activities. SAR investigations are also discussed in this review as they provide crucial details regarding the essential structural qualities that benzimidazole derivatives must have in order to be biologically active, which could aid in the rational design of new drug candidates. Benzimidazole scaffold is an exclusive structure in drug design and discovery. Many new pharmaceutical drugs containing benzimidazole are anticipated to be available within the next ten years as a result of the extensive therapeutic applications of benzimidazole and its derivatives. This review inspired many researchers to develop more biologically active compounds bearing benzimidazole, expanding the scope of finding a remedy for other diseases. From this study, we concluded that 2-substituted benzimidazole was considered more extensively by researchers.

Discovery of Novel Inhibitors of Cruzain Cysteine Protease of Trypanosoma cruzi

Chagas disease (CD) is a parasitic disease endemic in several developing countries. According to the World Health Organization, approximately 6-8 million people worldwide are inflicted by CD. The scarcity of new drugs, mainly for the chronic phase, is the main reason for treatment limitation in CD. Therefore, there is an urgent need to discover new targets for which new therapeutical agents could be developed. Cruzain cysteine protease (CCP) is a promising alternative because this enzyme exhibits pleiotropic effects by acting as a virulence factor, modulating host immune cells, and interacting with host cells. This systematic review was conducted to discover new compounds that act as cruzain inhibitors, and their effects in vitro were studied through enzymatic assays and molecular docking. Additionally, the advances and perspectives of these inhibitors are discussed. These findings are expected to contribute to medicinal chemistry in view of the design of new, safe, and efficacious inhibitors against Trypanosoma cruzi CCP detected in the last decade (2013-2022) to provide scaffolds for further optimization, aiming toward the discovery of new drugs.

Design, synthesis, and molecular docking studies of benzimidazole-1,3,4-triazole hybrids as carbonic anhydrase I and II inhibitors

In this study, with an aim to develop novel heterocyclic hybrids as potent enzyme inhibitors, we synthesized a series of 10 novel 2-(4-(4-ethyl-5-(2-(substitutedphenyl)-2-oxo-ethylthio)-4H-1,2,4-triazol-3-yl)-phenyl)-5,6-dimethyl-1H-benzimidazole (5a-5j) derivatives and characterized by 1 H-NMR, 13 C-NMR, and HRMS. These compounds were evaluated for their inhibitory activity against hCA I and hCA II. All the compounds exhibited good hCA I and hCA II inhibitory activities with IC50 values in range of 1.288 μM-3.122 μM. Among all these compounds, compound 5e, with an IC50 value of 1.288 μM is the most active against carbonic hCA I. Compound 5h with an IC50 value of 1.532 μM is the most active against carbonic hCA-II. Compounds 5a-5j were also evaluated for their cytotoxic effects on the L929 mouse fibroblast (normal) cell line. The compounds were also analyzed for their antioxidant capacity by TAS, FRAP, and DPPH activity. Enzyme inhibition kinetics showed all compounds 5a-5j to inhibit the enzyme by non-competitive. The most active compound 5e for hCA I and compound 5h for hCA-II were subjected to molecular docking, which revealed their binding interactions with the enzyme's active site, confirming the experimental findings.

Synthesis, antimicrobial activity and molecular docking study of benzyl functionalized benzimidazole silver(I) complexes

In this study, a series of N-functionalized benzimidazole silver(I) complexes were prepared and characterized by FT-IR, 1H, 13C{1H} NMR spectroscopy, and elemental analysis. Synthesized N-benzylbenzimidazole silver(I) complexes were evaluated for their antimicrobial activities against bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and the fungal strains Candida albicans and Candida glabrata. The results indicated that N-alkylbenzimidazole silver(I) complexes exhibited good antimicrobial activity compared to N-alkylbenzimidazole derivatives. Especially, complex 2e presented perfect antimicrobial activity than the other complexes. The characterized molecules were optimized by DFT-based calculation methods and the optimized molecules were analyzed in detail by molecular docking methods against bacterial DNA-gyrase and CYP51. The amino acid residues detected for both target molecules are consistent with expectations, and the calculated binding affinities and inhibition constants are promising for further studies. A series of N-alkylbenzimidazole silver(I) complexes were synthesized and fully characterized by means of 1H NMR, 13C NMR, and FT-IR spectroscopies. Synthesized N-alkylbenzimidazole silver(I) complexes were investigated for their antimicrobial activities against bacteria Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and the fungal strains Candida albicans and Candida glabrata. All complexes showed better activity according to Ampicilin against Pseudomonas aeruginosa. The molecules which were firstly optimized by DFT-based calculation methods were also analyzed by molecular docking methods against DNA gyrase of E. Coli and CYP51. 338 × 190 mm (96 × 96 DPI).

Urea Hydrogen Peroxide and Ethyl Lactate, an Eco-Friendly Combo System in the Direct C(sp2)-H Bond Selenylation of Imidazo[2,1-b]thiazole and Related Structures

Herein, we describe a urea hydrogen peroxide-mediated sustainable protocol for the synthesis of selenylated imidazo[2,1-b]thiazole by using half molar equivalent diorganyl diselenides in ethyl lactate as a greener solvent. The reaction features high yields, easy performance on gram scale, metal-free conditions, as well as applicability to imidazopyridine and imidazopyrimidine.

The medicinal panorama of benzimidazoles and their scaffolds as anticancer and antithrombotic agents: A review

Nitrogen-containing heterocyclic scaffolds have become a prospective pharmacophore with therapeutic importance due to their biological similarities with natural and synthetic drugs. Among all nitrogen heterocyclic compounds, benzimidazoles and their derivatives are privileged molecules structurally akin to naturally available nucleotides, enabling them to intercommunicate with numerous biopolymers in biological systems. This reason enlightens modern researchers worldwide to assess their potential significance in the context of synthetic and biological chemistry. Therefore, it is crucial to merge the latest data with the prior documentation to apprehend the ongoing situation of the benzimidazole moiety in various therapeutic zones of research. The current work displays that the benzimidazole center is a versatile nucleus that offers the necessary data of synthetic alterations for pre-existing compounds to provide new scaffolds to resist numerous therapeutic sectors, including those associated with anticancer and antithrombosis. Due to the potential significance of benzimidazoles, this review aims to emphasize the latest innovations in synthesizing several other notable benzimidazole substrates and their significant pharmacological prospects for the future, including anticancer and antithrombosis.

Antimalarial Imidazopyridines Incorporating an Intramolecular Hydrogen Bonding Motif: Medicinal Chemistry and Mechanistic Studies

We previously identified a novel class of antimalarial benzimidazoles incorporating an intramolecular hydrogen bonding motif. The frontrunner of the series, analogue A, showed nanomolar activity against the chloroquine-sensitive NF54 and multi-drug-resistant K1 strains of Plasmodium falciparum (PfNF54 IC₅₀ = 0.079 μM; PfK1 IC₅₀ = 0.335 μM). Here, we describe a cell-based medicinal chemistry structure-activity relationship study using compound A as a basis. This effort led to the identification of novel antimalarial imidazopyridines with activities of <1 μM, favorable cytotoxicity profiles, and good physicochemical properties. Analogue 14 ( PfNF54 IC₅₀ = 0.08 μM; PfK1 IC₅₀ = 0.10 μM) was identified as the frontrunner of the series. Preliminary mode of action studies employing molecular docking, live-cell confocal microscopy, and a cellular heme fractionation assay revealed that 14 does not directly inhibit the conversion of heme to hemozoin, although it could be involved in other processes in the parasite's digestive vacuole.

NaClO-Mediated Cross Installation of Indoles and Azoles Benefits Anticancer Hit Discovery

Innovations in synthetic chemistry have a profound impact on the drug discovery process, and will always be a necessary driver of drug development. As a result, it is of significance to develop novel simple and effective synthetic installation of medicinal modules to promote drug discovery. Herein, we have developed a NaClO-mediated cross installation of indoles and azoles, both of which are frequently encountered in drugs and natural products. This effective toolbox provides a convenient synthetic route to access a library of N-linked 2-(azol-1-yl) indole derivatives, and can be used for late-stage modification of drugs, natural products and peptides. Moreover, biological screening of the library has revealed that several adducts showed promising anticancer activities against A549 and NCI-H1975 cells, which give us a hit for anticancer drug discovery.

In Vitro Determination of Antileshmanial Activities of Benzimidazolium Derivatives on L. major Promastigotes and Amastigotes

PURPOSE

Leishmaniasis is a serious public health problem infecting millions of people worldwide. An effective and reliable treatment method to be used in the treatment of the disease has not been developed yet.

METHODS

In this article, the anti-leishmanial activities of two benzimidazolium derivatives (B.A and B.B) against Leishmania major promastigotes and amastigotes, which are known to cause cutaneous leishmaniasis, were investigated for the first time. The immunostimulatory activity of the developed formulations was determined using the J774 murine macrophage cell line.

RESULTS

B.A and B.B compounds were found to have a much higher cytotoxic effect than Amphotericin B (IC₅₀ value 0.75 μM ± 0.03), which is used as the reference drug. The IC₅₀ value was determined as 2.02 µM ± 0.52 for B.A and 1.83 µM ± 0.71 for B.B in Leishmania promastigotes. In addition, IC₅₀ values of B. A and B.B Leishmania amastigotes were found to be 1.01 µM and 0.67 µM, respectively. It was found that B.B was 81.12 times more selective than Amphotericin B and showed the highest selectivity against L. major promastigotes (359.09) and amastigotes (980.80). Considering the selectivity indices (SI) of B.A and B.B, both compounds tested are more promising than Amphotericin B.

CONCLUSION

The results showed that benzimidazolium derivatives have anti-leishmanial potential against L. major, which is the causative agent of cutaneous leishmaniasis. Thus, we can say that the obtained results will help the development of effective and safe antileishmanial drug formulations against cutaneous leishmaniasis.

Mechanochemistry Frees Thiourea Dioxide (TDO) from the 'Veils' of Solvent, Exposing All Its Reactivity

The synthesis of nitrogen-based heterocycles has always been considered essential in developing pharmaceuticals in medicine and agriculture. This explains why various synthetic approaches have been proposed in recent decades. However performing as methods, they often imply harsh conditions or the employment of toxic solvents and dangerous reagents. Mechanochemistry is undoubtedly one of the most promising technologies currently used for reducing any possible environmental impact, addressing the worldwide interest in counteracting environmental pollution. Following this line, we propose a new mechanochemical protocol for synthesizing various heterocyclic classes by exploiting thiourea dioxide (TDO)'s reducing proprieties and electrophilic nature. Simultaneously exploiting the low cost of a component of the textile industry such as TDO and all the advantages brought by a green technique such as mechanochemistry, we plot a route towards a more sustainable and eco-friendly methodology for preparing heterocyclic moieties.

Antiplasmodial activity, structure-activity relationship and studies on the action of novel benzimidazole derivatives

Malaria cases and deaths keep being excessively high every year. Some inroads gained in the last two decades have been eroded especially due to the surge of resistance to most antimalarials. The search for new molecules that can replace the ones currently in use cannot stop. In this report, the synthesis of benzimidazole derivatives guided by structure-activity parameters is presented. Thirty-six molecules obtained are analyzed according to their activity against P. falciparum HB3 strain based on the type of substituent on rings A and B, their electron donor/withdrawing, as well as their dimension/spatial properties. There is a preference for electron donating groups on ring A, such as Me in position 5, or better, 5, 6-diMe. Ring B must be of the pyridine type such as picolinamide, other modifications are generally not favorable. Two molecules, 1 and 33 displayed antiplasmodial activity in the high nanomolar range against the chloroquine sensitive strain, with selectivity indexes above 10. Activity results of 1, 12 and 16 on a chloroquine resistance strain indicated an activity close to chloroquine for compound 1. Analysis of some of their effect on the parasites seem to suggest that 1 and 33 affect only the parasite and use a route other than interference with hemozoin biocrystallization, the route used by chloroquine and most antimalarials.

Hypervalent iodine(iii) promoted C–H/C–H amination/annulation tandem reactions: synthesis of benzimidazoles from simple anilines and aldehydes

A novel hypervalent iodine mediated cascade transformation of anilines and aldehydes to benzimidazoles was developed.

N,2,6-Trisubstituted 1H-benzimidazole derivatives as a new scaffold of antimicrobial and anticancer agents: design, synthesis, in vitro evaluation, and in silico studies

Compounds containing benzimidazole moiety occupy privileged chemical space for discovering new bioactive substances. In continuation of our recent work, 69 benzimidazole derivatives were designed and synthesized with good to excellent yields of 46-99% using efficient synthesis protocol i.e. sodium metabisulfite catalyzed condensation of aromatic aldehydes with o-phenylenediamines to form 2-arylbenzimidazole derivatives followed by N-alkylation by conventional heating or microwave irradiation for diversification. Potent antibacterial compounds against MSSA and MRSA were discovered such as benzimidazole compounds 3k (2-(4-nitrophenyl), N-benzyl), 3l (2-(4-chlorophenyl), N-(4-chlorobenzyl)), 4c (2-(4-chlorophenyl), 6-methyl, N-benzyl), 4g (2-(4-nitrophenyl), 6-methyl, N-benzyl), and 4j (2-(4-nitrophenyl), 6-methyl, N-(4-chlorobenzyl)) with MIC of 4-16 μg mL-1. In addition, compound 4c showed good antimicrobial activities (MIC = 16 μg mL-1) against the bacteria strains Escherichia coli and Streptococcus faecalis. Moreover, compounds 3k, 3l, 4c, 4g, and 4j have been found to kill HepG2, MDA-MB-231, MCF7, RMS, and C26 cancer cells with low μM IC50 (2.39-10.95). These compounds showed comparable drug-like properties as ciprofloxacin, fluconazole, and paclitaxel in computational ADMET profiling. Finally, docking studies were used to assess potential protein targets responsible for their biological activities. Especially, we found that DHFR is a promising target both in silico and in vitro with compound 4c having IC50 of 2.35 μM.

Microfluidics Biocatalysis System Applied for the Synthesis of N-Substituted Benzimidazole Derivatives by Aza-Michael Addition

Benzimidazole scaffolds became an attractive subject due to their broad spectrum of pharmacological activities. In this work, a methodology was developed for the synthesis of N-substituted benzimidazole derivatives from benzimidazoles and α, β-unsaturated compounds (acrylonitriles, acrylate esters, phenyl vinyl sulfone) catalyzed by lipase TL IM from Thermomyces lanuginosus in continuous-flow microreactors. Investigations were conducted on reaction parameters such as solvent, substrate ratio, reaction temperature, reactant donor/acceptor structures, and reaction time. The transformation is promoted by inexpensive and readily available lipase in methanol at 45 °C for 35 min. A wide range of β-amino sulfone, β-amino nitrile, and β-amino carbonyl compounds were efficiently and selectively synthesized in high yields (76–97%). All in all, a microfluidic biocatalysis system was applied to the synthesis of N-substituted benzimidazole derivatives, and could serve as a promising fast synthesis strategy for further research to develop novel and highly potent active drugs.

Quinoline-imidazole/benzimidazole derivatives as dual-/multi-targeting hybrids inhibitors with anticancer and antimicrobial activity

Two new classes of hybrid quinoline-imidazole/benzimidazole derivatives (the hybrid QIBS salts and QIBC cycloadducts) were designed and synthesized to evaluate their anticancer and antimicrobial activity. The strategy adopted for synthesis is straight and efficient, in four steps: N-acylation, N-alkylation, quaternization and a Huisgen 3 + 2 cycloaddition. The in vitro single-dose anticancer assay of forty six hybrid quinoline-benzimidazole compounds reveal that one QIBS salt (11h), has an excellent quasi nonselective activity against all type of cancer cell with an excellent PGI in the area of 90-100% and very good lethality. Three others quinoline-imidazole/benzimidazole hybrids (8h, 12h, 12f) has an excellent selective activity against some cancer cell lines: breast cancer MDA-MB-468 and Leukemia HL-60 TB). The five-dose assay screening confirms that compound 11h possesses excellent anti-proliferative activity, with GI₅₀ in the range of nano-molar, against some cancer cell lines: Leukemia HL-60 TB, Leukemia K-526, Leukemia RPMI-8226, Breast cancer MDA-MB-468, Lung cancer HOP-92 and Ovarian cancer IGROV1. The antibacterial assay indicates that three hybrid QIBS salts (12f, 12c, 12d) have an excellent activity against Gram-negative bacteria E. coli (superior to control Gentamicin) while against Gram-positive bacteria S. aureus only one compound 8i (R₂ = -CF3) exhibits a significant activity (superior to control Gentamicin). The MIC assay indicates that two other compounds (11h, 12h) are biologically active to a very low concentration, in the range of nano-molar. We believe that all these excellent assets related to anticancer and antibacterial activities, make from our hybrid quinoline-imidazole/benzimidazole compounds bearing a phenyl group (R₂ = -C₆H₅) in the para (4)-position of the benzoyl moiety a good candidate for future drug developing.

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.

Zinc Coordination Compounds with Benzimidazole Derivatives: Synthesis, Structure, Antimicrobial Activity and Potential Anticancer Application

Developing new, smart drugs with the anticancer activity is crucial, especially for cancers, which cause the highest mortality in humans. In this paper we describe a series of coordination compounds with the element of health, zinc, and bioactive ligands, benzimidazole derivatives. By way of synthesis we have obtained four compounds named C1, C2, C4 and C4. Analytical analyses (elemental analysis (EA), flame atomic absorption spectrometry (FAAS)), spectroscopic (Fourier transform infrared spectroscopy (FT-IR), mass spectrometry (MS)) and thermogravimetric (TG) methods and the definition of crystal structures were used to explore the nature of bonding and to elucidate the chemical structures. The collected analytical data allowed the determination of the stoichiometry in coordination compounds, thermal stability, crystal structure and way of bonding. The cytotoxicity effect of the new compounds as a potential antitumor agent on the glioblastoma (T98G), neuroblastoma (SK-N-AS) and lung adenocarcinoma (A549) cell lines and human normal skin fibroblasts (CCD-1059Sk) was also determined. Cell viability was determined by the MTT assay. The results obtained confirmed that conversion of ligands into the respective metal complexes significantly improved their anticancer properties. The complexes were screened for antibacterial and antifungal activities. The ADME technique was used to determine the physicochemical and biological properties.

Design and synthesis of benzimidazole derivatives as antimycobacterial agents

A series of 2,5-disubstituted benzimidazole derivatives was synthesized with the aim to identify compounds with potent anti-TB activity. All the compounds were screened in vitro against cultured Mycobacterium tuberculosis H₃₇ Rv strain and found to be exhibiting MIC₉₉ values in the range of 0.195-100 µM. Out of 43 synthesized compounds, two compounds 11h and 13e showed better anti-TB activity than the reference drug isoniazid.

Quorum Sensing and Biofilm Disrupting Potential of Imidazole Derivatives in Chromobacterium violaceum Using Antimicrobial and Drug Discovery Approaches

Population of drug-resistant bacteria have increased at an alarming rate in the past few decades. The major reason for increasing drug resistance is the lack of new antibiotics and limited drug targets. It has therefore been a vital task to develop new antibiotics with different drug targets. Two such targets are biofilm formation and quorum sensing. Quorum sensing is cell to cell communication used by bacteria that initiates many important survival processes and aids in establishing pathogenesis. Both biofilm and quorum sensing are inter-related processes and play a major role in physiological and pathogenesis processes. In this study, five novel imidazole derivatives (IMA-1-IMA-5) were synthesised and tested for their antibacterial and anti-quorum sensing activities against Chromobacterium violaceum using different in silico and in vitro techniques following the standard protocols. In silico results revealed that all compounds were able to effectively bind to and interact sufficiently with the target protein CviR. CviR is a protein to which autoinducers bind to initiate the quorum sensing process. In silico results also revealed that the compounds generated favourable structural dynamics implying that the compounds would be able to effectively bind to CviR and inhibit quorum sensing. Susceptibility results revealed that IMA-1 is the most active of all the derivatives against both planktonic cells and biofilms. Qualitative and quantitative evaluation of anti-quorum sensing activity at sub-inhibitory concentrations of these compounds also revealed high activity for IMA-1. Down-regulation of most of the quorum sensing genes when cells were treated with the test compounds affirmed the high anti-quorum sensing activities of these compounds. The results from this study are promising and urges on the use of anti-quorum sensing and biofilm disrupting molecules to combat multi-drug resistance problem.

N-methyl Benzimidazole Tethered Cholic Acid Amphiphiles Can Eradicate S. aureus-Mediated Biofilms and Wound Infections

Infections associated with Gram-positive bacteria like S. aureus pose a major threat as these bacteria can develop resistance and thereby limit the applications of antibiotics. Therefore, there is a need for new antibacterials to mitigate these infections. Bacterial membranes present an attractive therapeutic target as these membranes are anionic in nature and have a low chance of developing modifications in their physicochemical features. Antimicrobial peptides (AMPs) can disrupt the microbial membranes via electrostatic interactions, but the poor stability of AMPs halts their clinical translation. Here, we present the synthesis of eight N-methyl benzimidazole substituted cholic acid amphiphiles as antibacterial agents. We screened these novel heterocyclic cholic acid amphiphiles against different pathogens. Among the series, CABI-6 outperformed the other amphiphiles in terms of bactericidal activity against S. aureus. The membrane disruptive property of CABI-6 using a fluorescence-based assay has also been investigated, and it was inferred that CABI-6 can enhance the production of reactive oxygen species. We further demonstrated that CABI-6 can clear the pre-formed biofilms and can mitigate wound infection in murine models.

1-Mesityl-3-(3-Sulfonatopropyl) Imidazolium Protects Against Oxidative Stress and Delays Proteotoxicity in C. elegans

Due to the increase in life expectancy worldwide, age-related disorders such as neurodegenerative diseases (NDs) have become more prevalent. Conventional treatments comprise drugs that only attenuate some of the symptoms, but fail to arrest or delay neuronal proteotoxicity that characterizes these diseases. Due to their diverse biological activities, imidazole rings are intensively explored as powerful scaffolds for the development of new bioactive molecules. By using C. elegans, our work aims to explore novel biological roles for these compounds. To this end, we have tested the in vivo anti-proteotoxic effects of imidazolium salts. Since NDs have been largely linked to impaired antioxidant defense mechanisms, we focused on 1-Mesityl-3-(3-sulfonatopropyl) imidazolium (MSI), one of the imidazolium salts that we identified as capable of improving iron-induced oxidative stress resistance in wild-type animals. By combining mutant and gene expression analysis we have determined that this protective effect depends on the activation of the Heat Shock Transcription Factor (HSF-1), whereas it is independent of other canonical cytoprotective molecules such as abnormal Dauer Formation-16 (DAF-16/FOXO) and Skinhead-1 (SKN-1/Nrf2). To delve deeper into the biological roles of MSI, we analyzed the impact of this compound on previously established C. elegans models of protein aggregation. We found that MSI ameliorates β-amyloid-induced paralysis in worms expressing the pathological protein involved in Alzheimer’s Disease. Moreover, this compound also delays age-related locomotion decline in other proteotoxic C. elegans models, suggesting a broad protective effect. Taken together, our results point to MSI as a promising anti-proteotoxic compound and provide proof of concept of the potential of imidazole derivatives in the development of novel therapies to retard age-related proteotoxic diseases.

Design, synthesis, biological evaluation and QSAR analysis of novel N-substituted benzimidazole derived carboxamides

As a result of our previous research focussed on benzimidazoles, herein we present design, synthesis, QSAR analysis and biological activity of novel N-substituted benzimidazole derived carboxamides. Carboxamides were designed to study the influence of the number of methoxy groups, the type of the substituent placed at the benzimidazole core on biological activity. Pronounced antioxidative activity displayed unsubstituted 28 (IC₅₀ ≈ 3.78 mM, 538.81 mmolFe²⁺/mmolC) and dimethoxy substituted derivative 34 (IC₅₀ ≈ 5.68 mM, 618.10 mmolFe²⁺/mmolC). Trimethoxy substituted 43 and unsubstituted compound 40 with isobutyl side chain at N atom showed strong activity against HCT116 (IC₅₀ ≈ 0.6 µM, both) and H 460 cells (IC₅₀ ≈ 2.5 µM; 0.4 µM), being less cytotoxic towards non-tumour cell. Antioxidative activity in cell generally confirmed relatively modest antioxidant capacity obtained in DPPH/FRAP assays of derivatives 34 and 40. The 3D-QSAR models were generated to explore molecular properties that have the highest influence on antioxidative activity.

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.

Benzimidazoles Against Certain Breast Cancer Drug Targets: A Review

BACKGROUND

Benzimidazoles are widely used scaffolds against various types of cancer including breast cancer. To this end, anticancer agents must be developed using the knowledge of the specific targets of BC.

OBJECTIVE

In this study, we aim to review the compounds used against some of the biomolecular targets of breast cancer. To this end, we present information about the various targets, with their latest innovative studies.

CONCLUSION

Benzimidazole ring is an important building block that can target diverse cancer scenarios since it can structurally mimic biomolecules in the human body. Additionally, many studies imply the involvement of this moiety on a plethora of pathways and enzymes related to BC. Herein, our target-based collection of benzimidazole derivatives strongly suggests the utilization of benzimidazole derivatives against BC.

Acid Dissociation Constants of the Benzimidazole Unit in the Polybenzimidazole Chain: Configuration Effects

The acid dissociation constant of three benzimidazoles, namely 2,2′-bibenzo[d]imidazole, 2,5′-bibenzo[d]imidazole, and 5,5′-bibenzo[d]imidazole, have been investigated by means of density functional theory calculations in gas phase and in aqueous solution. The theoretical approach was validated by the comparing of predicted and experimentally determined pK_a values in imidazole, benzimidazole, and 2-phenylbenzimidazole. From the studied compounds, 2,2′-bibenzo[d]imidazole was found to be the most acidic, which made it a valuable candidate as a material for polymer electrolyte membrane fuel cells.