Synthesis, DFT Calculations, In Silico Studies, and Antimicrobial Evaluation of Benzimidazole-Thiadiazole Derivatives.

In this study, a series of new benzimidazole-thiadiazole hybrids were synthesized, and the synthesized compounds were screened for their antimicrobial activities against eight species of pathogenic bacteria and three fungal species. Azithromycin, voriconazole, and fluconazole were used as reference drugs in the mtt assay. Among them, compounds 5f and 5h showed potent antifungal activity against C. albicans with a MIC of 3.90 µg/mL. Further, the results of the antimicrobial assay for compounds 5a, 5b, 5f, and 5h proved to be potent against E. faecalis (ATCC 2942) on the basis of an acceptable MIC value of 3.90 µg/mL. The cytotoxic effects of compounds that are effective as a result of their antimicrobial activity on healthy mouse fibroblast cells (L929) were evaluated. According to HOMO-LUMO analysis, compound 5h (with the lower ΔE = 3.417 eV) is chemically more reactive than the other molecules, which is compatible with the highest antibacterial and antifungal activity results. A molecular docking study was performed to understand their binding modes within the sterol 14-α demethylase active site and to interpret their promising fungal inhibitory activities. Molecular dynamics (MD) simulations of the most potent compounds 5f and 5h were found to be quite stable in the active site of the 14-α demethylase (5TZ1) protein.

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.

Design, synthesis, molecular modeling, DFT, ADME and biological evaluation studies of some new 1,3,4-oxadiazole linked benzimidazoles as anticancer agents and aromatase inhibitors.

Breast cancer is the most frequent female cancer and second cause of cancer-related deaths among women around the world. Two thirds of breast cancer patients have hormone-dependent tumors, which is very likely be treated with hormonal therapy. Aromatase is involved in the biosynthesis of estrogen thus a critical target for breast cancer. In this study, in order to identify new aromatase enzyme inhibitors, a series of benzimidazole-1,3,4-oxadiazole derivatives were synthesized and characterized by 1H NMR, 13C NMR, and MS spectra analyses. In the in vitro anticancer assay, all the compounds tested anticancer activities using MTT-based assay against five cancer cell lines (MCF-7, A549, HeLa, C6, and HepG2). Among them, compound 5a exhibited the most potent activity with IC50 values of 5.165 ± 0.211 µM and 5.995 ± 0.264 µM against MCF-7 and HepG2 cell lines. Compound 5a was included in the BrdU test to determine the DNA synthesis inhibition effects for both cell types. Furthermore, compound 5c was also found to be more effective than doxorubicin on the HeLa cell line. The selectivity of anticancer activity was evaluated in NIH3T3 cell line. In vitro, enzymatic inhibition assays of aromatase enzyme were performed for compound 5a acting on the MCF-7 cell line. For compound 5a, in silico molecular docking and dynamics simulations against aromatase enzyme was performed to determine possible protein-ligand interactions and stability. DFT study was performed to evaluate the quantum mechanical and electronic properties of compound 5a. Finally, the theoretical ADME properties of the potential aromatase inhibitor compound 5a were analyzed by calculations.Communicated by Ramaswamy H. Sarma.

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.

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.

Clinical and Immunological Effects of Er,Cr:YSGG Laser in Nonsurgical Periodontal Treatment: A Randomized Clinical Trial.

Objective: The aim of this study was to compare the clinical and immunological results of nonsurgical periodontal treatment with or without the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser. Background data: As lasers have begun to be used in dentistry, the Er,Cr:YSGG laser has started to attract attention in the field of periodontology. Materials and methods: Fifty-nine nonsmoking patients with advanced chronic periodontitis were randomly allocated to a test group (full-mouth ultrasonic supra- and subgingival debridement+Er,Cr:YSGG laser application) and a control group (full-mouth ultrasonic supra- and subgingival debridement+root planing with Gracey curettes). The laser parameters were set as follows: 1.5 W output power, pulse mode H (pulse duration of 140 µs), pulse frequency of 20 Hz, and an air-water spray ratio of 10% air and 15% water. The instrumentation was performed until the operator felt that the root surfaces were adequately debrided. Probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), plaque index, interleukin-1 beta (IL-1ß), matrix metalloproteinase-8 (MMP-8), tissue inhibitor metalloproteinase-1 (TIMP-1), and MMP-8/TIMP-1 levels in gingival crevicular fluid were evaluated at baseline, 6 weeks, and 3 months postoperatively. Results: There were statistically significant differences in PD, which was our primary outcome, and BOP between the groups at both examinations [p < 0.001 and p < 0.001 (for PD) and p = 0.048 and p < 0.001 (for BOP), respectively], in favor of the laser group. However, there were no significant differences among groups at any time for CAL gain (p = 563 and p = 369, respectively). No significant differences in MMP-8, TIMP-1, and MMP-8/TIMP-1 levels were detected among groups. There was a statistically significant difference for IL-1ß levels among groups at 3-month evaluations in favor of the laser group. Conclusions: Using the Er,Cr:YSGG laser instead of hand instruments in nonsurgical periodontal treatment has shown additional improvements in terms of pocket reduction and gingival bleeding compared with traditional nonsurgical therapy.