A new series of hydrazones as small-molecule aldose reductase inhibitors.

In the search for small-molecule aldose reductase (AR) inhibitors, new tetrazole-hydrazone hybrids (1-15) were designed. An efficient procedure was employed for the synthesis of compounds 1-15. All hydrazones were subjected to an in vitro assay to assess their AR inhibitory profiles. Compounds 1-15 caused AR inhibition with Ki values ranging between 0.177 and 6.322 µM and IC50 values ranging between 0.210 and 0.676 µM. 2-[(1-(4-Hydroxyphenyl)-1H-tetrazol-5-yl)thio]-N'-(4-fluorobenzylidene)acetohydrazide (4) was the most potent inhibitor of AR in this series. Compound 4 markedly inhibited AR (IC50 = 0.297 µM) in a competitive manner (Ki = 0.177 µM) compared to epalrestat (Ki = 0.857 µM, IC50 = 0.267 µM). Based on the in vitro data obtained by applying the MTT test, compound 4 showed no cytotoxic activity toward normal (NIH/3T3) cells at the tested concentrations, indicating its safety as an AR inhibitor. Compound 4 exhibited proper interactions with crucial amino acid residues within the active site of AR. In silico QikProp data of all hydrazones (1-15) were also determined to assess their pharmacokinetic profiles. Taken together, compound 4 stands out as a promising inhibitor of AR for further in vivo studies.

A new series of thiazole-hydrazone hybrids for Akt-targeted therapy of non-small cell lung cancer.

In an attempt to identify potent antitumor agents for the fight against non-small cell lung cancer, new thiazolyl hydrazones (2a-n) were synthesized and examined for their in vitro cytotoxic effects on A549 human lung adenocarcinoma and L929 mouse embryonic fibroblast cells by means of the MTT assay. Furthermore, the effects of the most potent anticancer agents on apoptosis and Akt inhibition were investigated. 2-[2-((Isoquinolin-5-yl)methylene)hydrazinyl]-4-(4-methylsulfonylphenyl)thiazole (2k) (IC50 = 1.43 ± 0.12 µM) and 2-[2-((isoquinolin-5-yl)methylene)hydrazinyl]-4-(1,3-benzodioxol-5-yl)thiazole (2l) (IC50 = 1.75 ± 0.07 µM) displayed more pronounced anticancer activity than cisplatin (IC50 = 3.90 ± 0.10 µM) on A549 cell lines; 2-[2-((isoquinolin-5-yl)methylene)hydrazinyl]-4-(4-methoxyphenyl)thiazole (2j) (IC50 = 3.93 ± 0.06 µM) showed anticancer activity close to cisplatin. These compounds were found to induce apoptosis in A549 cells. Compound 2j (IC50 = 3.55 ± 0.64 µM) showed stronger Akt inhibitory activity than GSK690693 (IC50 = 4.93 ± 0.06 µM), while compounds 2k and 2l did not cause Akt inhibition at IC50 concentrations (1.43 and 1.75 µM, respectively). To comprehensively elucidate the binding pose of compound 2j and to provide a detailed understanding on the ligand' binding mechanism, induced-fit docking calculations were also conducted. Both in vitro and in silico studies suggest that compound 2j shows its cytotoxic and apoptotic effects on A549 cell lines via Akt inhibition. However, it is understood that compounds 2k and 2l exert their strong anticancer effects on A549 cells through different pathways.

A new series of thiosemicarbazone-based anti-inflammatory agents exerting their action through cyclooxygenase inhibition.

In an endeavor to identify potent anti-inflammatory agents, new thiosemicarbazones (TSCs) incorporated into a diaryl ether framework (2a-2l) were prepared and screened for their in vitro inhibitory effects on cyclooxygenases (COXs). 4-[4-(Piperidin-1-ylsulfonyl)phenyl]-1-[4-(4-cyanophenoxy)benzylidene]thiosemicarbazide (2c) was the most potent and selective COX-1 inhibitor in this series, with an IC50 value of 1.89 ± 0.04 µM. On the other hand, 4-[4-(piperidin-1-ylsulfonyl)phenyl]-1-[4-(4-nitrophenoxy)benzylidene]thiosemicarbazide (2b) was identified as a nonselective COX inhibitor (COX-1 IC50 = 13.44 ± 0.65 µM, COX-2 IC50 = 12.60 ± 0.78 µM). Based on molecular docking studies, the diaryl ether and the TSC groups serve as crucial moieties for interactions with pivotal amino acid residues in the active sites of COXs. According to MTT test, compounds 2b and 2c showed low cytotoxic activity toward NIH/3T3 cells. Their in vivo anti-inflammatory and antioxidant potencies were also assessed using the lipopolysaccharide-induced sepsis model. Compounds 2b and 2c diminished high-sensitivity C-reactive protein, myeloperoxidase, nitric oxide, and malondialdehyde levels. Both compounds also caused a significant decrease in aspartate aminotransferase levels as well as alanine aminotransferase levels. In silico pharmacokinetic studies suggest that compounds 2b and 2c possess favorable drug-likeness and oral bioavailability. It can be concluded that these compounds may act as orally bioavailable anti-inflammatory and antioxidant agents.

Novel metabolic enzyme inhibitors designed through the molecular hybridization of thiazole and pyrazoline scaffolds.

New hybrid thiazolyl-pyrazoline derivatives (4a-k) were obtained through a facile and versatile synthetic procedure, and their inhibitory effects on the human carbonic anhydrase (hCA) isoforms I and II as well as on acetylcholinesterase (AChE) were determined. All new thiazolyl-pyrazolines showed activity at nanomolar levels as hCA I, hCA II, and AChE inhibitors, with KI values in the range of 13.35-63.79, 7.01-115.80, and 17.89-48.05 nM, respectively. 1-[4-(4-Cyanophenyl)thiazol-2-yl]-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4f) and 1-(4-phenylthiazol-2-yl)-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4a) against hCAs and 1-[4-(4-chlorophenyl)thiazol-2-yl]-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4d) and 1-[4-(4-nitrophenyl)thiazol-2-yl]-3-(4-piperidinophenyl)-5-(4-fluorophenyl)-2-pyrazoline (4b) against AChE were identified as highly potent inhibitors, superior to the standard drugs, acetazolamide and tacrine, respectively. Compounds 4a-k were also evaluated for their cytotoxic effects on the L929 mouse fibroblast (normal) cell line. Moreover, a comprehensive ligand-receptor interaction prediction was performed using the ADME-Tox, Glide XP, and MM-GBSA modules of the Schrödinger Small-Molecule Drug Discovery Suite to elucidate the potential binding modes of the new hybrid inhibitors against these metabolic enzymes.

A New Series of Antileukemic Agents: Design, Synthesis, In Vitro and In Silico Evaluation of Thiazole-Based ABL1 Kinase Inhibitors.

BACKGROUND: After the approval of imatinib, more than 25 antitumor agents targeting kinases have been approved, and several promising candidates are at various stages of clinical evaluation. OBJECTIVES: Due to the importance of the thiazole scaffold in targeted anticancer drug discovery, the goal of this work is to identify new thiazolyl hydrazones as potent ABL1 kinase inhibitors for the management of Chronic Myeloid Leukemia (CML). METHODS: New thiazolyl hydrazones (2a-p) were synthesized and investigated for their cytotoxic effects on the K562 CML cell line. Compounds 2h, 2j and 2l showed potent anticancer activity against K562 cell line. The cytotoxic effects of these compounds on other leukemia (HL-60, MT-2 and Jurkat) and HeLa human cervical carcinoma cell lines were also investigated. Furthermore, their cytotoxic effects on Mitogen-Activated Peripheral Blood Mononuclear Cells (MA-PBMCs) were evaluated to determine their selectivity. Due to its selective and potent anticancer activity, compound 2j was benchmarked for its apoptosis-inducing potential on K562 cell line and inhibitory effects on eight different Tyrosine Kinases (TKs), including ABL1 kinase. In order to investigate the binding mode of compound 2j into the ATP binding site of ABL1 kinase (PDB: 1IEP), a molecular docking study was conducted using MOE 2018.01 program. The QikProp module of Schrödinger's Molecular modelling package was used to predict the pharmacokinetic properties of compounds 2a-p. RESULTS: 4-(4-(Methylsulfonyl)phenyl)-2-[2-((1,3-benzodioxol-4-yl)methylene)hydrazinyl]thiazole (2j) showed antiproliferative activity against K562 cell line with an IC50 value of 8.87±1.93 µM similar to imatinib (IC50= 6.84±1.11µM). Compound 2j was found to be more effective than imatinib on HL-60, Jurkat and MT-2 cells. Compound 2j also showed cytotoxic activity against HeLa cell line similar to imatinib. The higher selectivity index value of compound 2j than imatinib indicated that its antiproliferative activity was selective. Compound 2j also induced apoptosis in K562 cell line more than imatinib. Among eight TKs, compound 2j showed the strongest inhibitory activity against ABL1 kinase enzyme (IC50= 5.37±1.17µM). According to molecular docking studies, compound 2j exhibited high affinity to the ATP binding site of ABL1 kinase, forming significant intermolecular interactions. On the basis of in silico studies, this compound did not violate Lipinski's rule of five and Jorgensen's rule of three. CONCLUSION: Compound 2j stands out as a potential orally bioavailable ABL1 kinase inhibitor for the treatment of CML.

Design, synthesis, in vitro and in silico evaluation of new pyrrole derivatives as monoamine oxidase inhibitors.

In an effort to develop potent monoamine oxidase (MAO) inhibitors, new pyrrole derivatives were obtained via the selective reduction of the CC bonds of 1-(1-methyl-1H-pyrrol-2-yl)-3-[5-(aryl)furan-2-yl]prop-2-en-1-ones through palladium catalyzed hydrogenation in ethanol. The synthesized compounds were screened for their inhibitory effects on MAO-A and MAO-B by an in vitro fluorometric method. The selectivity index (SI) value was given as the ratio of IC50 (MAO-A)/IC50 (MAO-B) for each compound. 3-(5-(4-Chlorophenyl)furan-2-yl)-1-(1-methyl-1H-pyrrol-2-yl)propan-1-one (6) was identified as the most selective MAO-A inhibitor in this series, with an IC50 value of 0.162 µM and a SI value of 0.002. Kinetic studies were also carried out to assess the nature of MAO-A inhibition by compound 6. According to Lineweaver-Burk plots, compound 6 was found to be a competitive MAO-A inhibitor and the Ki value of compound 6 was determined as 0.1221 µM. Docking studies were performed for compound 6 and clorgyline using the human MAO-A crystal structure (PDB ID: 2Z5Y). The docking results showed that compound 6 presented similar interactions as clorgyline in the active center cavity of the enzyme. Molinspiration software was used to determine the physicochemical parameters of all compounds for an evaluation of their compliance to Lipinski's rule of five. Compound 6 did not violate Lipinski's rule, making it a potential orally bioavailable therapeutic agent.

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.

Synthesis and Evaluation of a New Series of Arylidene Indanones as Potential Anticancer Agents.

BACKGROUND: Arylidene indanones have attracted a great deal of interest due to their outstanding therapeutic applications. In particular, considerable research has pointed out the importance of arylidene indanones in the field of cancer research. OBJECTIVE: The aim of the current work was to design and synthesize arylidene indanone-based anticancer agents. METHOD: New arylidene indanones were obtained via the Claisen-Schmidt condensation of 5-chloro-6-methoxy- 2,3-dihydro-1H-inden-1-one with p-substituted benzaldehyde derivatives. MTT assay was performed to evaluate their cytotoxic effects on MCF-7 human breast adenocarcinoma, HeLa human cervix carcinoma and NIH/3T3 mouse embryonic fibroblast cell lines. The most effective derivatives were evaluated for their DNA synthesis inhibitory and apoptotic effects. The most apoptotic compounds were also investigated for their effects on caspase-3 activation in HeLa cells. The binding interactions of the most effective caspase-3 activator at the active site of caspase-3 were confirmed through molecular docking studies using Schrodinger's Maestro molecular modeling package. RESULTS AND CONCLUSION: Compounds 2, 3, 4, 5, 6 and 7 exhibited selective anticancer activity against HeLa cells, whilst compounds 7 and 10 showed selective anticancer activity against MCF-7 cells. Compound 10 caused significant DNA synthesis inhibition on MCF-7 cells, whereas compound 3 caused significant DNA synthesis inhibition on HeLa cells. Compounds 2 and 3 were determined as the most apoptotic agents against HeLa cells, whereas compounds 7 and 10 showed apoptotic activity against MCF-7 cells. Besides, compound 2 was identified as the most effective compound on caspase-3 activation in HeLa cells. Docking studies showed that compound 2 interacted with the residues His121 and Tyr204 forming π-π stacking interactions.

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 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.