New benzimidazole-oxadiazole derivatives: Synthesis, α-glucosidase, α-amylase activity, and molecular modeling studies as potential antidiabetic agents.

Benzimidazole-1,3,4-oxadiazole derivatives (5a-z) were synthesized and characterized with different spectroscopic techniques such as 1 H NMR, 13 C NMR, and HRMS. The synthesized analogs were examined against α-glucosidase and α-amylase enzymes to determine their antidiabetic potential. Compounds 5g and 5q showed the most activity with 35.04 ± 1.28 and 47.60 ± 2.16 µg/mL when compared with the reference drug acarbose (IC50 = 54.63 ± 1.95 µg/mL). Compounds 5g, 5o, 5s, and 5x were screened against the α-amylase enzyme and were found to show excellent potential, with IC50 values ranging from 22.39 ± 1.40 to 32.07 ± 1.55 µg/mL, when compared with the standard acarbose (IC50 = 46.21 ± 1.49 µg/mL). The antioxidant activities of the effective compounds (5o, 5g, 5s, 5x, and 5q) were evaluated by TAS methods. A molecular docking research study was conducted to identify the active site and explain the functions of the active chemicals. To investigate the most likely binding mode of the substances 5g, 5o, 5q, 5s, and 5x, a molecular dynamics simulation was also carried out.

Design, synthesis, and biological activity of novel dithiocarbamate-methylsulfonyl hybrids as carbonic anhydrase inhibitors.

Carbonic anhydrase (CA) enzymes are involved in many physiological events. These enzymes, which contain Zn2+ in their structure, can be easily inhibited by dithiocarbamate compounds. In addition, CA enzyme inhibitory activities are known in groups such as sulfonamide and methylsulfonyl. For this purpose, in this study, a series of 23 new dithiocarbamate-methylsulfonyl derivatives were synthesized and their CA enzyme inhibitory activities were investigated. The inhibition potentials of the obtained compounds against the human CA I and CA II enzymes were investigated by the in vitro enzyme isolation method. It is seen that the compounds show activity at the nanomolar level. Molecular docking studies of the compounds were carried out by in silico methods. The poses of compounds 2a, 2e, 2o, and 2t are presented.

Design and synthesis of novel chalcone derivatives and evaluation of their inhibitory activities against acetylcholinesterase.

According to the cholinergic hypothesis, an increase in the acetylcholine level in Alzheimer's disease patients relatively slows down the symptoms of the disease. The most commonly used drug, donepezil, is a cholinesterase inhibitor. In this study, 12 new chalcones (2a-l) were designed and synthesized. In biological activity studies, the acetylcholinesterase (AChE) and butyrylcholinesterase inhibitory potentials of all compounds were evaluated using the in vitro Ellman method. The biological evaluation showed that compounds 2d, 2f, 2j, and 2l displayed significant activity against AChE. The compounds 2d, 2f, 2j, and 2l displayed IC50 values of 0.042, 0.024, 0.053, and 0.033 µM against AChE, respectively. The reference drug donepezil (IC50 = 0.021 µM) also displayed significant inhibition of AChE. The inhibitory activities of these compounds for ß-amyloid plaque aggregation were investigated. The enzyme kinetic study was performed to observe the effect of the most active compound 2f on the substrate-enzyme relationship, and a mixed-type inhibition of AchE was determined. Further, docking simulation also revealed that these compounds (2d, 2f, 2j, and 2l) interacted with the enzyme active site in a similar manner to donepezil. The most active derivative, compound 2f, interacted with the amino acids Trp286, Phe295, Tyr341, Trp86, and Glu202.

Design, synthesis, biological activity, molecular docking, and molecular dynamics of novel benzimidazole derivatives as potential AChE/MAO-B dual inhibitors.

To develop new acetylcholinesterase (AChE)-monoamine oxidase-B (MAO-B) dual inhibitors against Alzheimer's disease, the benzimidazole ring, which has a propargyl side chain with previously proven selective MAO-B inhibitory activity, was used as the main structure. Moreover, like donepezil, it was thought that the enzyme AChE would provide π-π interactions with the peripheral anionic side in this structure. Piperazine derivatives were chosen for the cationic active site. The synthesis of the compounds was carried out in five steps. The structures of the compounds were determined using 1 H-NMR (nuclear magnetic resonance), 13 C-NMR, and high-resolution mass spectrometry spectroscopic methods. First, the in vitro AChE, butyrylcholinesterase (BChE), MAO-A, and MAO-B inhibitory potentials of the obtained compounds were investigated. As a result of activity tests, compounds 5b, 5e, 5g, and 5h showed inhibitory activity against AChE; compounds 5e and 5g showed inhibitory activity against MAO-B. None of the compounds showed inhibitory activity against BChE or MAO-A. Compounds 5e and 5g showed dual inhibition. Among these compounds, compound 5g had inhibition potential similar to that of donepezil and selegiline. For compound 5g, further kinetic studies and Aß-plaque inhibitory potentials were investigated using in vitro methods. Molecular docking studies were performed using both AChE and hMAO-B crystals to elucidate the compound's interactions with the enzyme active site. The binding modes of the compound on AChE were fully elucidated by molecular dynamics studies.

Design, Synthesis and Biological Evaluation of a Novel Series of Thiadiazole- Based Anticancer Agents as Potent Angiogenesis Inhibitors.

BACKGROUND: Thiadiazole has attracted a great deal of interest as a versatile heterocycle for the discovery and development of potent anticancer agents. Thiadiazole derivatives exert potent antitumor activity against a variety of human cancer cell lines through various mechanisms. OBJECTIVE: The goal of this work was to design and synthesize thiadiazole-based anticancer agents with anti-angiogenic activity. METHODS: N-aryl-2-[(5-(aryl)amino-1,3,4-thiadiazol-2-yl)thio]acetamides (4a-r) were synthesized via the reaction of 5-(aryl)amino-1,3,4-thiadiazole-2(3H)-thiones with N-(aryl)-2-chloroacetamides in the presence of potassium carbonate. The compounds were investigated for their cytotoxic effects on three cancer (A549, HepG2, SH-SY5Y), two normal (HUVEC and 3T3-L1) cell lines using MTT and WST-1 assays. In order to examine whether the compounds have anti-angiogenic effects or not, HUVECs were cultured on matrigel matrix to create a vascular-like tube formation. RESULTS: Compounds 4d, 4m and 4n were more effective on A549 human lung adenocarcinoma cells than cisplatin. The IC50 values of compounds 4d, 4m and 4n for A549 cell line were found to be 7.82 ± 0.4, 12.5 ± 0.22, 10.1 ± 0.52 µM, respectively when compared with cisplatin (IC50= 20 ± 0.51 µM), whilst their IC50 values for HUVEC cell line were determined as 138.7 ± 0.84, 78 ± 0.44, 177.6 ± 0.2 µM, respectively after 48 h of the treatment. The concentrations (10-20-50 µM) of compounds 4d, 4e, 4l, 4m, 4n, 4q and 4r were found to inhibit vascular like tube formation. CONCLUSION: According to their anticancer and anti-angiogenic effects, compounds 4d, 4m and 4n may be potential anticancer agents for further in vivo studies.

Design, synthesis, biological evaluation, and docking studies of some novel chalcones as selective COX-2 inhibitors.

A new series of chalcones (1-9) possessing an SO2 CH3 COX-2 pharmacophore at the para position of the C-1 phenyl ring was synthesized via the Claisen-Schmidt condensation reaction and examined for their inhibition potential against cyclooxygenase (COX) enzymes. Their structures were elucidated by infrared, 1 H NMR (nuclear magnetic resonance), 13 C NMR, and high-resolution mass spectroscopic methods. Enzyme inhibition studies revealed that most of the compounds showed a moderate-to-strong inhibitory activity (IC50 = 0.18-0.34 µM) against the COX-2 enzyme as compared with celecoxib (IC50 = 0.12 µM), ibuprofen (IC50 = 5.33 µM), and nimesulide (IC50 = 1.68 µM). Among these compounds, 1-[4-(methylsulfonyl)phenyl]-3-(2,3-dichlorophenyl)prop-2-en-1-one (5), 1-[4-(methylsulfonyl)phenyl]-3-(2,4-dichlorophenyl)prop-2-en-1-one (6), and 1-[4-(methylsulfonyl)phenyl]-3-(2-chloro-6-fluorophenyl)prop-2-en-1-one (8) became prominent with IC50 values of 0.21, 0.19, and 0.18 µM, respectively. According to molecular docking studies of the most effective compounds, it was found that the compounds interact with amino acids that are important in COX-2 selectivity, such as Arg499 and Phe504.

Synthesis and docking study of benzimidazole-triazolothiadiazine hybrids as aromatase inhibitors.

Aromatase is involved in the biosynthesis of estrogen and thus is a critical target for breast cancer. In this study, to identify new aromatase enzyme inhibitors, seven 3-[4-(5-methyl-1H-benzo[d]imidazol-2-yl)phenyl]-6-(substituted phenyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine derivatives were synthesized. First, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to determine the inhibitory activity of the synthesized compounds on the MCF-7 cell line. The aromatase inhibitory activity was determined for the active compounds 5b, 5c, 5e, and 5g on the MCF-7 cell line. Compound 5g showed significant aromatase inhibitory activity (IC50 = 0.037 ± 0.001 µM). Interestingly, this compound, which bears a difluoro substituent at positions 2 and 4 of the phenyl ring, displayed the most potent aromatase inhibitory activity without significant cytotoxicity to a normal healthy cell line (NIH3T3). Furthermore, the interactions between the best active compounds and the active site of the enzyme were analyzed through a docking study. The results of this study determined that benzimidazole-triazolothiadiazine derivatives are promising compounds that should be further developed as a novel class of aromatase inhibitors.

Synthesis and Evaluation of a Series of 1,3,4-Thiadiazole Derivatives as Potential Anticancer Agents.

BACKGROUND AND METHODS: In an attempt to develop potent antitumor agents, the synthesis of a series of N-(6-substituted benzothiazol-2-yl)-2-[(5-(arylamino)-1,3,4-thiadiazol-2-yl)thio]acetamides (1-14) was described and their cytotoxic effects on A549 human lung adenocarcinoma, MCF-7 human breast adenocarcinoma, HepG2 human hepatocellular carcinoma and NIH/3T3 mouse embryonic fibroblast cell lines were investigated using MTT assay. RESULTS: Phenyl-substituted compounds (8-14) were found to be more effective than naphthyl-substituted compounds (1-7) on cancer cells. Compounds 8, 9, 10, 12, 13 and 14 were identified as the most potent anticancer agents on MCF-7 and HepG2 cell lines and therefore their effects on DNA synthesis and apoptosis/necrosis in MCF-7 cell line were evaluated. Among these compounds, N-(6-methoxybenzothiazol-2-yl)-2-[(5- (phenylamino)-1,3,4-thiadiazol-2-yl)thio]acetamide (13) was the most selective anticancer agent against MCF-7 and HepG2 cell lines with a SI value of 100. On the other hand, compounds 8, 9, 10, 12, 13 and 14 inhibited DNA synthesis in MCF-7 cell line in a dose-dependent manner. Flow cytometric analyses clearly indicated that the compounds showed significant anticancer activity against MCF-7 cell line via the induction of apoptosis dose dependently. CONCLUSION: According to in vitro assays, compounds 8, 9, 10, 12, 13 and 14 stand out as promising candidates for further studies.

Toxicity and Synergistic Activities of Chalcones Against Aedes aegypti (Diptera: Culicidae) and Drosophila melanogaster (Diptera: Drosophilidae).

Mosquito-borne illnesses are of great concern throughout the world, and chemical insecticides are commonly employed to decrease mosquito populations. However, the developmental insecticide pipeline for vector control has primarily been filled by repurposed agricultural products, and is hampered by their widespread use and insecticide resistance. The present study was performed in the search for new chemical insecticides or insecticide synergists. Screening of 31 chalcone analogs was performed using Aedes aegypti (Linnaeus) first-instar larval toxicity assay, and oral feeding to Drosophila melanogaster's proper authority should be (Meigen). Synergism studies were performed by topically applying chalcones to adult female Ae. aegypti mosquitoes to examine its impact on activity of carbaryl, which was compared to piperonyl butoxide alone. Fourteen chalcone analogs had LC50 values in the range of 0.4-38 ppm against first-instar Ae. aegypti larvae, and three chalcones displayed toxicity against D. melanogaster via feeding (LC50 values ranged from 146-214 µg/ml). Two chalcones synergized carbaryl toxicity against adult Ae. aegypti with efficacy similar to piperonyl butoxide. As a result, it is concluded that chalcones may serve as novel insecticides and synergists after further structural optimization.

Synthesis and biological evaluation of a series of dithiocarbamates as new cholinesterase inhibitors.

In the present paper, a novel series of dithiocarbamates was synthesized via the treatment of 4-(trifluoromethyl)benzyl chloride with appropriate sodium salts of N,N-disubstituted dithiocarbamic acids. The chemical structures of the compounds were elucidated by (1) H NMR, mass spectral data, and elemental analyses. Each derivative was evaluated for its ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) using a modification of Ellman's spectrophotometric method. The most potent AChE inhibitor was found as compound 2g (IC50 = 0.53 ± 0.001 µM) followed by compounds 2f (IC50 = 0.74 ± 0.001 µM) and 2j (IC50 = 0.89 ± 0.002 µM) when compared with donepezil (IC50 = 0.048 ± 0.001 µM). Compounds 2f and 2g were more effective than donepezil (IC50 = 7.88 ± 0.52 µM) on BuChE inhibition. Compounds 2f and 2g exhibited the inhibitory effect on BuChE with IC50 values of 1.39 ± 0.041 and 3.64 ± 0.072 µM, respectively.

Synthesis and biological evaluation of some 1,2-disubstituted benzimidazole derivatives as new potential anticancer agents.

The synthesis of some new 1-(2-aryl-2-oxoethyl)-2-[(morpholine-4-yl)thioxomethyl]benzimidazole derivatives and investigation of their anticancer activities were the aims of this work. 2-(Chloromethyl)benzimidazole compound was reacted with sulfur and morpholine via Willgerodt-Kindler reaction to give 2-[(morpholine-4-yl)thioxomethyl]benzimidazole. Then, the obtained compound was reacted with appropriate α-bromoacetophenone derivatives in the presence of potassium carbonate to give the final products. Structure elucidation of the final compounds was achieved by FT-IR, (1)H NMR spectroscopy and MS spectrometry. The anticancer activities of the final compounds were evaluated by MTT assay, BrdU method, and flow cytometric analysis on C6, MCF-7, and A549 tumor cells. Most of the synthesized compounds exhibited considerable selectivity against the MCF-7 and C6 cell lines.

Synthesis and biological evaluation of some pyrazoline derivatives bearing a dithiocarbamate moiety as new cholinesterase inhibitors.

In the present study, new pyrazoline derivatives were synthesized via the reaction of 1-(chloroacetyl)-3-(2-furyl)-5-aryl-2-pyrazolines with sodium salts of N,N-disubstituted dithiocarbamic acids. Each derivative was evaluated for its ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) using a modification of Ellman's spectrophotometric method. The compounds were also investigated for their cytotoxic properties using the MTT assay. The most potent AChE inhibitor was found as compound 7 followed by compounds 27 and 17, when compared with eserine. Compounds effective on AChE carry the 2-dimethylaminoethyl moiety, which resembles the trimethylammonium group and the ethylene bridge of acetylcholine. Among all compounds, compound 7 bearing 2-dimethylaminoethyl and 3,4-methylenedioxyphenyl moieties was also found to be the most effective inhibitor of BuChE. The MTT assay indicated that the effective concentration of compound 7 was lower than its cytotoxic concentration.

Synthesis and antituberculosis activity of new hydrazide derivatives.

The increasing clinical importance of drug-resistant mycobacterial pathogens, especially Mycobacterium tuberculosis, has lent additional urgency to microbiological research and new antimycobacterial compound development. For this purpose, new hydrazide derivatives of imidazo[1,2-a]pyridine were synthesized and evaluated for antituberculosis activity. The reaction of 2-[(2-carboxyimidazo[1,2-a]pyridine-3-yl)sulfanyl]acetic acid hydrazide with various benzaldehydes gave N-(arylidene)-2-[(2-carboxyimidazo[1,2-a]pyridine-3-yl)sulfanyl]acetic acid hydrazide derivatives. The chemical structures of the compounds were elucidated by IR,(1)H-NMR, FAB-MS spectral data and elemental analysis. Antituberculosis activities of the synthesized compounds were determined by broth microdilution assay, the Microplate Alamar Blue Assay in BACTEC 12B medium. The results were screened in vitro, using the BACTEC 460 Radiometric System against Mycobacterium tuberculosis H37Rv (ATCC 27294) at 6.25 microg/mL; the tested compounds showed significant inhibition.