New Benzimidazole-Triazole Derivatives as Topoisomerase I Inhibitors: Design, Synthesis, Anticancer Screening, and Molecular Modeling Studies.

In this study, we designed, synthesized, and evaluated a series of 1,2,4-triazole benzimidazoles for their cytotoxic effects against the A549, C6, and NIH3T3 cell lines. Additionally, these compounds were assessed for their inhibitory activity against DNA topoisomerase I, aiming to develop novel anticancer agents. The synthesized final compounds 4a-h were characterized using 1H NMR, 13C NMR, and HRMS. Among them, compounds 4b and 4h emerged as the most potent agents against the A549 cell line, exhibiting an IC50 value of 7.34 ± 0.21 µM and 4.56 ± 0.18 µM, respectively. These results were compared to standard drugs, doxorubicin (IC50 = 12.420 ± 0.5 µM) and Hoechst 33342 (IC50 = 0.422 ± 0.02 µM). Notably, all tested compounds displayed higher cytotoxicity toward A549 cells than C6 cells. Compounds 4b and 4h demonstrated significant inhibitory activity against topoisomerase I, highlighting their potential as lead compounds in anticancer therapy. Subsequent in silico molecular docking studies were conducted to elucidate the potential binding interactions of compounds 4b and 4h with the target enzyme topoisomerase I. Molecular dynamics studies also assessed and validated the binding affinity and stability. These studies confirmed the promising binding affinity of these compounds, reinforcing their status as lead candidates. According to DFT, compound 4b having the lower energy gap value (ΔE = 3.598 eV) is more chemically reactive than the others, which is consistent with significant inhibitory activity against topoisomerase I. Furthermore, in silico ADME profiles for compounds 4b and 4h were evaluated using SwissADME, providing insights into their pharmacokinetic properties.

Synthesis and Molecular Docking of New N-Acyl Hydrazones- Benzimidazole as hCA I and II Inhibitors.

BACKGROUND: The carbonic anhydrases (CAs) which are found in most living organisms is a member of the zinc-containing metalloenzyme family. The abnormal levels and activities are frequently associated with various diseases therefore CAs have become an attractive target for the design of inhibitors or activators that can be used in the treatment of those diseases. METHODS: Herein, we have designed and synthesized new benzimidazole-hydrazone derivatives to investigate the effects of these synthesized compounds on CA isoenzymes. Chemical structures of synthesized compounds were confirmed by 1H NMR, 13C NMR, and HRMS. The synthetic derivatives were screened for their inhibitory potential against carbonic anhydrase I and II by in vitro assay. RESULTS: These compounds have IC50 values of 5.156-1.684 µM (hCA I) and 4.334-2.188 µM (hCA II). Inhibition types and Ki values of the compounds were determined. The Ki values of the compounds were 5.44 ± 0.14 µM-0.299 ± 0.01 µM (hCA I) and 3.699 ± 0.041 µM-1.507 ± 0.01 µM (hCA II). The synthetic compounds displayed inhibitory action comparable to that of the clinically utilized reference substance, acetazolamide. According to this, compound 3p was the most effective molecule with an IC50 value of 1.684 µM. Accordingly, the type of inhibition was noncompetitive and the Ki value was 0.299 ± 0.01 µM. CONCLUSION: According to the in vitro test results, detailed protein-ligand interactions of the compound 3p, which is more active against hCA I than standard azithromycin (AZM), were analyzed. In addition, the cytotoxic effects of the compounds on the L929 healthy cell line were evaluated.

Synthesis, Molecular Docking, Dynamics, Quantum-Chemical Computation, and Antimicrobial Activity Studies of Some New Benzimidazole-Thiadiazole Hybrids.

In this study, some new compounds, which are 2-aminothiadiazole derivatives linked by a phenyl bridge to the 2-position of the benzimidazole ring, were designed and synthesized as antimicrobial agents. The structures of the compounds were elucidated by 1H and 13C NMR spectroscopy, high-resolution mass spectrometry, and elemental analysis. The antifungal activities of the synthesized compounds were tested on Candida albicans, Candida krusei, Candida glabrata, and Candida parapsilosis. Compound 5f is more active against C. albicans and C. glabrata than standard fluconazole and varicanazole. Compounds were also evaluated for their counteracting activity against Gram-positive Escherichia coli, Serratia marcescens, Klebsiella pneumoniae, and Pseudomonas aeruginosa and Gram-negative Enterococcus faecalis, Bacillus subtilis, and Staphylococcus aureus. Compounds 5c and 5h had minimum inhibitory concentrations against E. faecalis close to that of the standard azithromycin. Molecular docking studies were performed against Candida species' 14-α demethylase enzyme. 5f was the most active compound against Candida species, which gave the highest docking interaction energy. The stabilities of compounds 5c and 5f with CYP51 were tested using 100 ns molecular dynamics simulations. According to the theoretical ADME calculations, the profiles of the compounds are suitable in terms of limiting rules. HOMO-LUMO analysis showed that 5h is chemically more reactive (represented with the lower ΔE = 3.432 eV) than the other molecules, which is compatible with the highest antibacterial activity result.

Design, Synthesis, and Molecular Modeling Studies of a Novel Benzimidazole as an Aromatase Inhibitor.

In this study, a series of novel 1,3,4-oxadiazole-benzimidazole derivatives were designed and synthesized. Their cytotoxic activities against five cancer cell lines, including A549, MCF-7, C6, HepG2, and HeLa, were evaluated by the MTT assay. The compounds 5b,c showed satisfactory potencies with much higher anticancer activity in comparison to the reference drug doxorubicin against the studied cancer cell lines. In vitro, enzymatic inhibition assays of aromatase (ARO) enzymes were performed. Molecular docking, molecular dynamics simulations, and binding free energy analyses were used to better understand the structure-activity connections and mechanism of action of the aromatase inhibitors. Two types of satisfactory 3D-QSAR (CoMFA and CoMSIA) models were generated, to predict the inhibitory activities of the novel inhibitors. Molecular docking studies were also carried out to find their binding sites and types of their interactions with the aromatase enzyme. Additionally, molecular dynamics simulations were performed to explore the most likely binding modes of compounds 5b,c with CYP19A1.

Synthesis, characterization, molecular docking, dynamics simulations, and in silico absorption, distribution, metabolism, and excretion (ADME) studies of new thiazolylhydrazone derivatives as butyrylcholinesterase inhibitors.

In this study, two novel series of thiazolylhydrazone derivatives containing 4-ethylpiperazine (3a-3f) and 4-methoxyphenylpiperazine (3g-3l) side chains were synthesized and their structures were characterized by spectral (1H NMR, 13C NMR, and MS spectra) analyses. In vitro inhibitory activities of synthesized compounds against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were determined by Ellman method. According to the results, all compounds showed a weak inhibitory effect on AChE, while promising results were obtained on BChE. Among the synthesized compounds, the activities of the derivatives carrying 4-ethylpiperazine (3a-3f) structure were found to be more effective than the compounds carrying 4-methoxyphenyl piperazine (3g-3l) derivatives. Especially, compound 3f bearing the nitro substituent was found to be the most promising compound on BChE in the series. The absorption, distribution, metabolism, and excretion (ADME) parameters of the synthesized compounds were predicted by using the SwissADME server. The potential binding mode and stability of compound 3f with BChE were investigated by the molecular docking and dynamics simulations. The results showed that 3f was strongly bound up with BChE with the optimal conformation; in addition, their binding free energy reached -167.936 ± 13.109 kJ/mol.

Design, synthesis and biological assessment of new selective COX-2 inhibitors including methyl sulfonyl moiety.

Nonsteroidal anti-inflammatory drugs (NSAIDs) cause peptic lesions in the gastrointestinal mucosa by inhibiting the cyclooxygenase-1 (COX-1) enzyme. Selective COX-2 inhibition causes decreased side effects over current NSAIDs. Therefore, the studies about selective inhibition of COX-2 enzyme are very important for new drug development. The design, synthesis and biological activity evaluation of novel derivatives bearing thiazolylhydrazine-methyl sulfonyl moiety as selective COX-2 inhibitors were aimed in this paper. The structures of synthesized compounds were assigned using different spectroscopic techniques such as 1H NMR, 13C NMR and HRMS. In addition, the estimation of ADME parameters for all compounds was carried out using in silico process. The evaluation of in vitro COX-1/COX-2 enzyme inhibition was applied according to the fluorometric method. According to the enzyme inhibition results, synthesized compounds showed the selectivity against COX-2 enzyme inhibition as expected. Compounds 3a, 3e, 3f, 3g, 3i and 3j demonstrated significant COX-2 inhibition potencies. Among them, compound 3a was found to be the most effective derivative with an IC50 value of 0.140 ± 0.006 µM. Moreover, it was seen that compound 3a displayed a more potent inhibition profile at least 12-fold than nimesulide (IC50 = 1.684 ± 0.079 µM), while it showed inhibitory activity at a similar rate of celecoxib (IC50 = 0.132 ± 0.005 µM). Molecular modelling studies aided in the understanding of the interaction modes between this compound and COX-2 enzyme. It was found that compound 3a had a significant binding property. In addition, the selectivity of obtained derivatives on COX-2 enzyme could be explained and discussed by molecular docking studies.

Synthesis, investigation of biological effects and in silico studies of new benzimidazole derivatives as aromatase inhibitors.

Inhibition of aromatase enzymes is very important in the prevention of estrogen-related diseases and the regulation of estrogen levels. Aromatase enzyme is involved in the final stage of the biosynthesis of estrogen, in the conversion of androgens to estrogen. The development of new compounds for the inhibition of aromatase enzymes is an important area for medicinal chemists in this respect. In the present study, new benzimidazole derivatives have been designed and synthesized which have reported anticancer activity in the literature. Their anticancer activity was evaluated against human A549 and MCF-7 cell lines by MTT assay. In the series, concerning MCF-7 cell line, the most potent compounds were the 4-benzylpiperidine derivatives 2c, 2g, and 2k with IC50 values of 0.032 ± 0.001, 0.024 ± 0.001, and 0.035 ± 0.001 µM, respectively, compared to the reference drug cisplatin (IC50 = 0.021 ± 0.001 µM). Then, these compounds were subject to further in silico aromatase enzyme inhibition assays to determine the possible binding modes and interactions underlying their activity. Thanks to molecular docking studies, the effectiveness of these compounds against aromatase enzyme could be simulated. Consequently, it has been found that these compounds can be settled very properly to the active site of the aromatase enzyme.

Synthesis, characterization and carbonic anhydrase I and II inhibitory evaluation of new sulfonamide derivatives bearing dithiocarbamate.

In this study, novel dithiocarbamate-sulfonamide derivatives (3a-3k) were synthesized to investigate their inhibitory activity on purified human carbonic anhydrase (hCA) I and II. The IC50 and Ki values of the compounds were calculated to compare their inhibition profiles on hCA I and II isoenzymes. Acetazolamide was used as the standard inhibitor in the enzyme inhibition assay. Compounds 3a, 3e, 3g, 3h, 3j and 3k showed notable inhibitory effects against hCA I and II. Among these compounds, compound 3h was found to be the most active derivate against both the hCA I and II enzymes with Ki values of 0.032 ± 0.001 µM and 0.013 ± 0.0005 µM, respectively. The cytotoxicity of compounds 3a, 3e, 3g, 3h, 3j and 3k toward NIH/3T3 (mouse embryonic fibroblast cell line) was observed and the compounds were found to be non-cytotoxic. Furthermore, molecular docking studies were performed to investigate the interaction types between compound 3h and the hCA I and II enzymes. As a result of this study a novel and potent class of CA inhibitors with good activity potential were identified.

Synthesis and biological evaluation of novel 1,3,4-thiadiazole derivatives as possible anticancer agents.

The synthesis of new N-(5-substituted-1,3,4-thiadiazol-2-yl)-2-[(5-(substituted amino)-1,3,4-thiadiazol-2-yl)thio]acetamide derivatives and investigation of their anticancer activities were the aims of this work. All the new compounds' structures were elucidated by elemental analyses, IR, 1H NMR, 13C NMR and MS spectral data. Anticancer activity studies of the compounds were evaluated against MCF-7 and A549 tumor cell lines. In addition, with the purpose of determining the selectivity of cytotoxic activities, the most active compound was screened against a noncancer NIH3T3 cell line (mouse embryonic fibroblast cells). Among the tested compounds, compound 4y (N-(5-ethyl-1,3,4-thiadiazol-2-yl)-2-((5-(p-tolylamino)-1,3,4-thiadiazol-2-yl)thio)acetamide), showed promising cytotoxic activity against MCF7 cancer cell with an IC 50value of 0.084 ± 0.020 mmol L-1 and against A549 cancer cell with IC 50 value of 0.034 ± 0.008 mmol L-1, compared with cisplatin. The aromatase inhibitory activity was evaluated for compound 4y on MCF-7 cell line showing promising activity with IC50 of 0.062 ± 0.004 mmol L-1.

Synthesis, molecular docking analysis and carbonic anhydrase I-II inhibitory evaluation of new sulfonamide derivatives.

New sulfonamide-hydrazone derivatives (3a-3n) were synthesized to evaluate their inhibitory effects on purified human carbonic anhydrase (hCA) I and II. The inhibition profiles of the synthesized compounds on hCA I-II isoenzyme were investigated by comparing their IC50 and Ki values. Acetazolamide (5-acetamido-1,3,4-thiadiazole-2-sulfonamide, AZA) has also been used as a standard inhibitor. The compound 3e demonstrated the best hCA I inhibitory effect with a Ki value of 0.1676 ±â€¯0.017 µM. Besides, the compound 3m showed the best hCA II inhibitory effect with a Ki value of 0.2880 ±â€¯0.080 µM. Cytotoxicity of the compounds 3e and 3m toward NIH/3T3 mouse embryonic fibroblast cell line was observed and the compounds were found to be non-cytotoxic. Molecular docking studies were performed to investigate the interaction types between active compounds and hCA enzymes. Pharmacokinetic profiles of compounds were assessed by theoretical ADME predictions. As a result of this study a novel and potent class of CA inhibitors were identified with a good activity potential.

Synthesis and Anticandidal Activity Evaluation of New Benzimidazole-Thiazole Derivatives.

Azole-based antifungal agents constitute one of the important classes of antifungal drugs. Hence, in the present work, 12 new benzimidazole-thiazole derivatives 3a-3l were synthesized to evaluate their anticandidal activity against C.albicans, C.glabrata, C.krusei, and C.parapsilopsis. The structures of the newly synthesized compounds 3a-3l were confirmed by IR, ¹H-NMR, 13C-NMR, and ESI-MS spectroscopic methods. ADME parameters of synthesized compounds 3a-3l were predicted by an in-slico study and it was determined that all synthesized compounds may have a good pharmacokinetic profile. In the anticandidal activity studies, compounds 3c and 3d were found to be the most active compounds against all Candida species. In addition, cytoxicity studies showed that these compounds are nontoxic with a IC50 value higher than 500 µg/mL. The effect of compounds 3c and 3d on the ergosterol level of C.albicans was determined by an LC-MS-MS method. It was observed that both compounds cause a decrease in the ergosterol level. A molecular docking study including binding modes of 3c to lanosterol 14α-demethylase (CYP51), a key enzyme in ergosterol biosynthesis, was performed to elucidate the mechanism of the antifungal action. The docking studies revealed that there is a strong interaction between CYP51 and the most active compound 3c.

Pharmacological and Toxicological Screening of Novel Benzimidazole-Morpholine Derivatives as Dual-Acting Inhibitors.

The aim of this study was to investigate acetylcholinesterase (AChE), monoamine oxidase A (MAO-A), monoamine oxidase B (MAO-B), cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzyme inhibitory, and antimicrobial activities of a new series of 2-(4-substituted phenyl)-1-[2-(morpholin-4-yl)ethyl]-1H-benzimidazole derivatives, for their possible use as multi-action therapeutic agents. Target compounds (n = 15) were synthesized under microwave irradiation conditions in two steps, and their structures were elucidated by FT-IR, ¹H-NMR, 13C-NMR and high resolution mass spectroscopic analyses. Pharmacological screening studies revealed that two of the compounds (2b and 2j) have inhibitory potential on both COX-1 and COX-2 enzymes. In addition, cytotoxic and genotoxic properties of the compounds 2b, 2j and 2m were investigated via the well-known MTT and Ames tests, which revealed that the mentioned compounds are non-cytotoxic and non-genotoxic. As a concise conclusion, two novel compounds were characterized as potential candidates for treatment of frequently encountered inflammatory diseases.

Synthesis of New Fluoro-Benzimidazole Derivatives as an Approach towards the Discovery of Novel Intestinal Antiseptic Drug Candidates.

In the present study, nineteen new fluoro-benzimidazole derivatives, including nifuroxazide analogs, were synthesized by microwave-supported reactions and tested against a panel of pathogenic microorganisms consisting of resistant strains. The synthesized compounds were characterized and identified by FT-IR, 1H- and 13C-NMR, mass spectroscopy, and elemental analyses, respectively. In vitro antimicrobial and cytotoxic effects of the synthesized compounds were determined by microdilution and by [3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide] (MTT) assay. The compound 4-[5(6)-fluoro-1H-benzimidazol-2-yl)-N'-(2- methylbenzylidene)]benzohydrazide (18) showed particularly high inhibitory activity against the gastro-intestinal pathogens, such as Escherichia coli O157:H7, Escherichiacoli ATCC 8739, Escherichia coli ATCC 35218 and Salmonella typhimurium ATCC 13311 standard strains, with minimum inhibitory concentrations (MIC90) ranging from 0.49-0.98 µg/mL. The microbial panel contained a total of ten pathogens including Klebsiella sp., Mycobacterium sp., MRSA, etc., for which the level of inhibitory activity measured was higher than that exhibited by the tested concentrations (MIC > 1000 µg/mL). In vitro cytotoxicity results revealed that the inhibitory concentration (IC50) value (210.23 µg/mL) of compound 18 against CCD 841 CoN cells (human intestinal epithelial cell line) is about 430 times higher than its MIC90 value against the tested Escherichia coli strains. Furthermore, the docking study of compound 18 suggested that its structure is very compatible with the active site pocket of the phosphofructokinase-2 enzyme.