Synthesis and antibacterial evaluation of some novel imidazole and benzimidazole sulfonamides

In-vitro anticancer evaluation of newly designed and characterized tri/tetra-substituted imidazole congeners- maternal embryonic leucine zipper kinase inhibitors: Molecular docking and MD simulation approaches

Our cascading attempt to develop new potent molecules now involves designing a series of imidazole derivatives and synthesizing two sets of 2,4,5- tri-substituted (4a-4d) and 1,2,4,5-tetra-substituted (6a-6d) imidazole by the principle of Debus-Radziszewski multicomponent synthesis reaction. The structures of the obtained compounds were confirmed by 1H/13C NMR, FT-IR, elemental analysis, purity and the retention time was analyzed by HPLC. Based upon the binding affinity in the molecular docking studies, we have synthesized different imidazole derivatives from which compound 6c have been found to show more anti-proliferative activity by inducing apoptosis at a higher rate than the other compounds corroborating the in-silico prediction. The structure and crystallinity of compound 4d have been confirmed by single XRD analysis. The synthesized molecules were screened for their in vitro anti-cancer properties in triple negative breast cancer cell line (MDA-MB-231), pancreatic cancer cell lines (MIA PaCa-2) and oral squamous cell carcinoma cell line (H357) and results indicated that all the compounds inhibited the cell proliferation in a concentration-dependent manner at different time points. The compounds 4b and 6d were found to be effective against the S. aureus bacterial strain whereas only compound 4d fairly inhibited the fungal strain of T. rubrum with a MIC 12.5 μg/mL. Molecular docking study reveals good interaction of the synthesized compounds with known target MELK involved in oncogenesis having high binding profiles. The lead compound 6c was further analyzed by the detailed molecular dynamics study to establish the stability of the ligand-enzyme complex.

Chitosan/poly (ethylene oxide) nanofiber sponge with dual-responsive drug release and excellent antibacterial property

An ideal wound dressing can absorb wound exudate in time, and has the advantages of moisture permeability, oxygen permeability, rapid hemostatic performance, antibacterial and low-toxic, which are the key to wound healing. However, traditional wound dressings exist structural and functional defects, especially in controlling bleeding and active wound protection. Herein, a novel three-dimensional chitosan/ poly (ethylene oxide) sponge dressing (3D CS/PEO sponge-ZPC) consists of CS/PEO nanofiber sponge (carrier unit), Zn metal-organic framework grown in-situ (Zn-MOF, drug loading unit and antibacterial unit), curcumin (CUR, antibacterial unit), and poly[(N-isopropylacrylamide)-co-(methacrylic acid)] (P(NIPAM-co-MAA), 'gatekeepers' unit) to promote the wound healing by absorb exudate in time, accelerate hemostasis and inhibit bacteria growth. Due to the unique structure of the as-prepared 3D CS/PEO sponge-ZPC was endowed with smart stimuli-responsive drug release mode, rapid hemostatic performance and strong antibacterial property. The result of CUR release showed smart "ON-OFF" drug release mode. Antibacterial results verified strong antibacterial property up to 99.9 %. Hemolysis test showed that hemolysis ratio of 3D CS/PEO sponge-ZPC met the acceptable standard. The rapid hemostatic property was demonstrated by hemostatic test. High wound healing effect was confirmed in vivo. These results provide an important research basis for the design of new smart dressing.

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.

Design, synthesis, crystal structure, and in vitro antibacterial activities of sulfonamide derivatives bearing the 4-aminoquinazoline moiety

A total of 66 sulfonamide derivatives bearing the 4-aminoquinazoline moiety were designed and synthesized, and their structures were fully characterized by ¹H NMR, ¹³C NMR, and HRMS techniques. Among them, the structures of compounds 5A10 and 5B11 were further confirmed through X-ray single-crystal diffraction analyses. The bioassay results indicated that some of the target compounds displayed higher inhibition activities in vitro against the tested phytopathogenic bacteria. For example, compound 5A26 exhibited a strong anti-Xanthomonas oryzae pv. oryzicola (Xoc) efficacy with an EC₅₀ (half-maximal effective concentration) value of 30.6 μg/mL, over twofold more active than control agent bismerthiazol (BMT). Additionally, compound 5B14 had a good antibacterial effect against the phytopathogen Xanthomonas axonopodis pv. citric (Xac) with EC₅₀ = 34.5 μg/mL, significantly better than control agent BMT (71.5 μg/mL). The anti-Xoc mechanistic studies showed that compound 5A26 exerted its antibacterial efficacy by increasing the permeability of bacterial membrane, decreasing the content of extracellular polysaccharides, and triggering morphological changes of bacterial cells.

Recent Updates on the Synthesis of Bioactive Quinoxaline-Containing Sulfonamides

Quinoxaline is a privileged pharmacophore that has broad-spectrum applications in the fields of medicine, pharmacology and pharmaceutics. Similarly, the sulfonamide moiety is of considerable interest in medicinal chemistry, as it exhibits a wide range of pharmacological activities. Therefore, the therapeutic potential and biomedical applications of quinoxalines have been enhanced by incorporation of the sulfonamide group into their chemical framework. The present review surveyed the literature on the preparation, biological activities and structure-activity relationship (SAR) of quinoxaline sulfonamide derivatives due to their broad range of biomedical activities, such as diuretic, antibacterial, antifungal, neuropharmacological, antileishmanial, anti-inflammatory, anti-tumor and anticancer action. The current biological diagnostic findings in this literature review suggest that quinoxaline-linked sulfonamide hybrids are capable of being established as lead compounds; modifications on quinoxaline sulfonamide derivatives may give rise to advanced therapeutic agents against a wide variety of diseases.

Novel Dipeptides Bearing Sulfonamide as Antimalarial and Antitrypanosomal agents: Synthesis and Molecular Docking

OBJECTIVE

Currently, there is a problem of ineffective chemotherapy to trypanosomiasis and the increasing emergence of malarial drug-resistant parasites. This research aimed to develop new dipeptide-sulfonamides as antiprotozoal agents.

BACKGROUND

Protozoan parasites cause severe diseases, with human African trypanosomaisis (HAT) and malaria leading the list. The noted deficiencies of existing antitrypanosomal drugs and the worldwide resurgence of malaria, accompanied by the springing up of widespread drug-resistant protozoan parasites, represent a huge challenge in infectious disease treatment in tropical regions.

METHODS

In order to discover new antiprotozoal agents, ten novel p-nitrobenzenesulphonamide derivatives incorporating dipeptide moiety were synthesized by the condensation reaction of 3-methyl-2-(4-nitrophenylsulphonamido)pentanoic acid (6) with substituted acetamides (4a-j) using peptide coupling reagents, characterized using 1H and 13C NMR, FTIR, HRMS, and investigated for their antimalarial and antitrypanosomal activities in vivo employing standard methods.

RESULTS

At 100 mg/kg body weight, N-(2-(2,6-dimethylphenylamino)-2-oxoethyl)-3-methyl-2-(4-nitrophenylsulfonamido)pentanamide showed the highest activity by inhibiting P. berghei parasite by 79.89%, which was comparable with the standard drug (artemether-lumefantrine 79.77%). In the antitrypanosomal study, N-(2-(4-chlorophenylamino)-2-oxoethyl)-3-methyl-2-(4-nitrophenylsulfonamido)pentanamide, N-(2-(4-fluorophenylamino)-2-oxoethyl)-3-methyl-2-(4-nitrophenylsulfonamido)pentanamide, and N-(2-(3-chlorophenylamino)-2-oxoethyl)-3-methyl-2-(4-nitrophenylsulfonamido)pentanamide were most potent in clearing Trypanosome brucei in mice. However, they were less active than the standard drug (diminazene aceturate). Molecular docking results demonstrated good binding affinity among the reported derivatives and target proteins in the active place of the protein. The outcome of haematological analysis and liver and kidney function tests showed that the new compounds had no adverse effect on the blood and organs.

CONCLUSIONS

The results of this research showed that the new compounds demonstrated interesting antitrypanosomal and antimalarial potentials. However, further research should be carried out on the synthesized derivatives as promising drug candidates for trypanosomiasis and malaria.

Recent advancements on Benzimidazole: A versatile scaffold in medicinal chemistry

Benzimidazole is nitrogen containing fused heterocycle which has been extensively explored in medicinal chemistry. Benzimidizole nucleus has been found to possess various biological activities such as anticancer, antimicrobial, anti-inflammatory, antiviral, antitubercular and antidiabetic. A number of benzimidazoles such as bendamustine, pantoprazole have been approved for the treatment of various illnesses whereas galeterone and GSK461364 are in clinical trials. The present review article gives an overview about the different biological activities exhibited by the benzimidazole derivatives as well as different methods used for the synthesis of benzimidazole derivatives for the past ten years.

Metal-Organic-Framework-Based Materials for Antimicrobial Applications

To address the serious threat of bacterial infection to public health, great efforts have been devoted to the development of antimicrobial agents for inhibiting bacterial growth, preventing biofilm formation, and sterilization. Very recently, metal-organic frameworks (MOFs) have emerged as promising materials for various antimicrobial applications owing to their different functions including the controlled/stimulated decomposition of components with bactericidal activity, strong interactions with bacterial membranes, and formation of photogenerated reactive oxygen species (ROS) as well as high loading and sustained releasing capacities for other antimicrobial materials. This review focuses on recent advances in the design, synthesis, and antimicrobial applications of MOF-based materials, which are classified by their roles as component-releasing (metal ions, ligands, or both), photocatalytic, and chelation antimicrobial agents as well as carriers or/and synergistic antimicrobial agents of other functional materials (antibiotics, enzymes, metals/metal oxides, carbon materials, etc.). The constituents, fundamental antimicrobial mechanisms, and evaluation of antimicrobial activities of these materials are highlighted to present the design principles of efficient MOF-based antimicrobial materials. The prospects and challenges in this research field are proposed.

An Updated Review on the Synthesis and Antibacterial Activity of Molecular Hybrids and Conjugates Bearing Imidazole Moiety

The rapid growth of serious infections caused by antibiotic resistant bacteria, especially the nosocomial ESKAPE pathogens, has been acknowledged by Governments and scientists and is one of the world's major health problems. Various strategies have been and are currently investigated and developed to reduce and/or delay the bacterial resistance. One of these strategies regards the design and development of antimicrobial hybrids and conjugates. This unprecedented critical review, in which our continuing interest in the synthesis and evaluation of the bioactivity of imidazole derivatives is testified, aims to summarise and comment on the results obtained from the end of the 1900s until February 2020 in studies conducted by numerous international research groups on the synthesis and evaluation of the antibacterial properties of imidazole-based molecular hybrids and conjugates in which the pharmacophoric constituents of these compounds are directly covalently linked or connected through a linker or spacer. In this review, significant attention was paid to summarise the strategies used to overcome the antibiotic resistance of pathogens whose infections are difficult to treat with conventional antibiotics. However, it does not include literature data on the synthesis and evaluation of the bioactivity of hybrids and conjugates in which an imidazole moiety is fused with a carbo- or heterocyclic subunit.

Synthesis of 99mTc-labeled 2-Mercaptobenzimidazole as a novel radiotracer to diagnose tumor hypoxia

Discovery of ^99mTc-labeled imidazole derivatives as a potential radiotracer for hypoxic tumor imaging is considered to be of great interest because of non-invasive detection capabilities. 2-Mercaptobenzimidazole (2-MBI) was successfully synthesized, characterized and radiolabeled with [^99mTc (CO)₃(H₂O)₃]⁺ intermediate to form ^99mTc-2-MBI complex with radiochemical purity of ≥95% yield as observed by instant-thin layer chromatography (ITLC) and radio-high performance liquid chromatography (radio-HPLC). The ^99mTc-2-MBI complex was observed to be stable in saline and serum with no noticeable decomposition at room temperature and 37 °C, respectively, over a time period of 24 h. Biodistribution results in Balb/c mice bearing S180 tumor show that ^99mTc-2-MBI highly internalized in tumor tissue, also possess preferably high tumor/muscle and tumor/blood ratios 4.14 ± 0.77 and 3.91 ± 0.63, respectively at 24 h incubation. Scintigraphic imaging study shows ^99mTc-2-MBI is visibly accumulated in hypoxic tumor tissue, suggesting it would be a promising radiotracer for early stage diagnosis of tumor hypoxia.

•

Radiolabeled imidazole derivatives are non-invasive imaging radiotracers

•

Benzoimidazole as basic subunit of biomolecules

•

Hypoxia or oxygen deprivation plays key role in tumor progression and resistance to therapy

•

Imidazole moiety reduce into reactive intermediary metabolites to show high accumulation in viable hypoxic cells

•

^99mTc-2-MBI radiotracer possess enhanced tumor/muscle and tumor/blood ratios

Antimicrobial evaluation of thiadiazino and thiazolo quinoxaline hybrids as potential DNA gyrase inhibitors; design, synthesis, characterization and morphological studies

A series of thiadiazino[5,6-b]quinoxaline and thiazolo[4,5-b]quinoxaline derivatives was designed and synthetized from the reaction of 2,3-dichloro-6-(morpholinosulfonyl)quinoxaline (2) with thiosemicarbazide or thiocarbohydrazide and thiourea derivatives to give nineteen quinoxaline derivatives 3-16. All the synthesized compounds were evaluated for in vitro antimicrobial potential against various bacteria and fungi strains that showed considerable antimicrobial activity against tested microorganisms. The most potent compounds 2, 7, 9, 10, 12 and 13c were exhibited bactericidal activity, in addition to fungistatic activity by dead live assay. Moreover, these compounds showed a significant result against all multi-drug resistance (MDRB) used especially compound 13c that displayed the best results with MICs of MDRB (1.95, 3.9, 2.6, 3.9 µg/mL) for stains used in this study, compared with Norfloxacin (1.25, 0.78, 1.57, 3.13 µg/mL). Also, cytotoxicity on normal cell (Vero cells ATCC CCL-81) by MTT assay was performed with lower toxicity results. Additionally, morphological studies, immunostimulatory potency and DNA gyrase inhibition assay of most active compounds was done. A molecular docking study has also been carried out to support the effective binding of the most promising compounds at the active site of the target enzyme S. aureus DNA gyrase (2XCT).

New chalcone-type compounds and 2-pyrazoline derivatives: synthesis and caspase-dependent anticancer activity

Aim: There is a continuous and urgent need for new anticancer agents with novel structures and target selectivity. Methods & results: The anticancer activity of the prepared compounds was assessed against human lung (A549) and stomach (AGS) cancer cell lines and evaluated in the noncancer human lung fibroblast (MRC-5) cell line. 2-Pyrazolines were devoid of toxicity in all cell lines used, chalcones bearing a β-(benz)imidazole moiety being toxic toward AGS cell line. Mechanistic studies showed that these compounds trigger loss of cell viability and mitochondrial membrane potential, while eliciting morphological traits compatible with regulated cell death, which was ultimately shown to derive from caspase activation, specifically caspase-3. Conclusion: Chalcones 1-3 have been identified as new and promising anticancer agents toward the AGS cell line.

Design, synthesis, in vitro antimicrobial evaluation and molecular docking studies of indol-2-one tagged with morpholinosulfonyl moiety as DNA gyrase inhibitors

A series of Schiff bases 3, 5, 7 and hydrazones 9 were achieved via reaction of 5-(morpholinosulfonyl)indol-2,3-dione (1) with appropriate amines and/or hydrazide derivatives. Representative compounds of the synthesized products were tested and evaluated as antimicrobial agents. According to MIC and MBC results from compounds 9a, 9c, 7a, 3b, 3c, and 5b were able to exhibit significant antibacterial activity against both Gram-positive and Gram-negative bacteria together with moderate antifungal activities. Also, a multi-drug resistance study (MDRS) was carried out to evaluate the activity of most potent compounds, and these compounds showed considerable results compared with Norfloxacin and Tetracycline which observed no results against strains used in this study. The inhibitory activity of most potent compounds (3b, 3c, 5b, 7a, 9a, and 9c) against DNA gyrase isolated from S. aureus was examined. The results indicated that all of these derivatives inhibiting DNA gyrase and therefore lead to separate bacterial DNA and inhibit cell division. Compounds 3b, 9c showed to be very potent inhibitors towards S. aureus DNA gyrase with IC₅₀ values (18.75 ± 1.2 and 19.32 ± 0.99 µM) respectively, compared with Ciprofloxacin (26.43 ± 0.64 µM). Molecular docking studies indicated that the synthesized compounds observed good binding with the enzyme and showed lower binding energy of the most promising compounds than a standard drug used, and enabled a better understanding of their structural features.

Synthesis and characterization of Ag(i) and Au(i) complexes with macrocyclic hybrid amine N-heterocyclic carbene ligands

N-Heterocyclic carbene Ag(i) and Au(i) complexes with various structures synthesized from four macrocyclic hybrid amine–benzimidazolium salts have been structurally characterized.

Synthesis, structures and luminescence properties of amine-bis(N-heterocyclic carbene) copper(i) and silver(i) complexes

Mononuclear Ag(i), Cu(i) and heterometallic Cu(i)/Ag(i) complexes with the tridentate amine-bis(N-heterocyclic carbene) were prepared, among which Cu(i)- and Cu/Ag complexes show luminescence properties.

Organic Compounds Based on (E)-N-Aryl-2-ethene-sulfonamide as Microtubule Targeted Agents in Prostate Cancer: QSAR Study

(E)-N-Aryl-2-ethene-sulfonamide and its derivatives are potent anticancer agents; these compounds inhibit cancer cells proliferation. A study of quantitative structure-activity relationship (QSAR) has been applied on 40 compounds based on (E)-N-Aryl-2-ethene-sulfonamide, in order to predict their anticancer biological activity. The principal components analysis is used for minimizing the base matrix and the multiple linear regression (MLR) and multiple nonlinear regression have been used to design the relationships between the molecular descriptor and anticancer properties of the sulfonamide derivatives. The validation of the models MLR and MNLR has been done by dividing the dataset into training and test set, the external validation of multiple correlation coefficients was RpIC50 = 0.81 for MLR and RpIC50 = 0.91 for MNLR. The artificial neural network (ANN) showed a correlation coefficient close to 0.96, which concluded that this latter model is more effective and much better than the other models. This obtained model (ANN) has been confirmed by two methods of LOO cross-validation and scrambling (or Y-randomization). The high correlation between experimental and predicted activity values was observed, indicating the validation and the good quality of the derived QSAR model.

Functionalized Benzimidazole Scaffolds: Privileged Heterocycle for Drug Design in Therapeutic Medicine

Benzimidazole derivatives are crucial structural scaffolds found in diverse libraries of biologically active compounds which are therapeutically useful agents in drug discovery and medicinal research. They are structural isosteres of naturally occurring nucleotides, which allows them to interact with the biopolymers of living systems. Hence, there is a need to couple the latest information with the earlier documentations to understand the current status of the benzimidazole nucleus in medicinal chemistry research. This present work unveils the benzimidazole core as a multifunctional nucleus that serves as a resourceful tool of information for synthetic modifications of old existing candidates in order to tackle drug resistance bottlenecks in therapeutic medicine. This manuscript deals with the recent advances in the synthesis of benzimidazole derivatives, the widespread biological activities as well as pharmacokinetic reports. These present them as a toolbox for fighting infectious diseases and also make them excellent candidates for future drug design.

Recent Development of Benzimidazole-Containing Antibacterial Agents

Clinically significant antibiotic resistance is one of the greatest challenges of the twenty-first century. However, new antibacterial agents are currently being developed at a much slower pace than our growing need for such drugs. Given their diverse biological activities and clinical applications, many bioactive heterocyclic compounds containing a benzimidazole nucleus have been the focus of interest for many researchers. The benzimidazole nucleus is a structural isostere of naturally occurring nucleotides. This advantage allows benzimidazoles to readily interact with the various biopolymers found in living systems. In view of this situation, much attention has been given to the exploration of benzimidazole-based antibacterial agents, leading to the discovery of many new chemical entities with intriguing profiles. In this minireview we summarize novel benzimidazole derivatives active against various bacterial strains. In particular, we outline the relationship between the structures of variously modified benzimidazoles and their antibacterial activity.

Bis-imidazolium and benzimidazolium based gemini-type ionic liquids structure: synthesis and antibacterial evaluation

The incorporated benzenesulfonamide moiety and the active side substituents in di-imidazolium and benzimidazolium cations enhanced both antibacterial activity and miscibility for the synthesized gemini type ILs.

A novel potentiometric self-plasticizing polypyrrole sensor based on a bidentate bis-NHC ligand for determination of Hg(ii) cation

In this approach, a new potentiometric self-plasticizing polypyrrole sensor was constructed based on a bidentate bis-NHC ligand for the purpose of Hg²⁺cation determination.