Showing papers in "Archiv Der Pharmazie in 2019"

Design, synthesis, molecular docking, and anticancer activity of benzoxazole derivatives as VEGFR-2 inhibitors.

Abstract: Novel series of benzoxazoles 4a-f -16 were designed, synthesized, and evaluated for anticancer activity against HepG2, HCT-116, and MCF-7 cells. HCT-116 was the most sensitive cell line to the influence of the new derivatives. In particular, compound 5e was found to be the most potent against HepG2, HCT-116, and MCF-7 with IC50 = 4.13 ± 0.2, 6.93 ± 0.3, and 8.67 ± 0.5 µM, respectively. Compounds 5c , 5f , 6b , 5d , and 6c showed the highest anticancer activities against HepG2 cells with IC50 of 5.93 ± 0.2, 6.58 ± 0.4, 8.10 ± 0.7, 8.75 ± 0.7, and 9.95 ± 0.9 µM, respectively; HCT-116 cells with IC50 of 7.14 ± 0.4, 9.10 ± 0.8, 7.91 ± 0.6, 9.52 ± 0.5, and 12.48 ± 1.1 µM, respectively; and MCF-7 cells with IC50 of 8.93 ± 0.6, 10.11 ± 0.9, 12.31 ± 1.0, 9.95 ± 0.8, and 15.70 ± 1.4 µM, respectively, compared with sorafenib as a reference drug with IC50 of 9.18 ± 0.6, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively. The most active compounds 5c-f and 6b,c were further evaluated for their vascular endothelial growth factor receptor-2 (VEGFR-2) inhibition. Compounds 5e and 5c potently inhibited VEGFR-2 at lower IC50 values of 0.07 ± 0.01 and 0.08 ± 0.01 µM, respectively, compared with sorafenib (IC50 = 0.1 ± 0.02 µM). Compound 5f potently inhibited VEGFR-2 at low IC50 value (0.10 ± 0.02 µM) equipotent to sorafenib. Our design was based on the essential pharmacophoric features of the VEGFR-2 inhibitor sorafenib. Molecular docking was performed for all compounds to assess their binding pattern and affinity toward the VEGFR-2 active site.

Emerging therapeutic potentials of dual-acting MAO and AChE inhibitors in Alzheimer's and Parkinson's diseases.

Abstract: No drug has been approved to prevent neuronal cell loss in patients suffering from Parkinson's disease (PD) or Alzheimer's disease (AD); despite increased comprehension of the underlying molecular causes, therapies target cognitive functional improvement and motor fluctuation control. Drug design strategies that adopt the "one protein, one target" philosophy fail to address the multifactorial aetiologies of neurodegenerative disorders such as AD and PD optimally. On the contrary, restoring neurotransmitter levels by combined combinatorial inhibition of cholinesterases, monoamine oxidases, and adenosine A2A A receptors, in conjunction with strategies to counter oxidative stress and beta-amyloid plaque accumulation, would constitute a therapeutically robust, multitarget approach. This extensive review delineates the therapeutic advantages of combining dual-acting molecules that inhibit monoamine oxidases and cholinesterases and/or adenosine A2A A receptors, and describes the structure-activity relationships of compound classes that include, but are not limited to, alkaloids, coumarins, chalcones, donepezil-propargylamine conjugates, homoisoflavonoids, resveratrol analogs, hydrazones, and pyrazolines. In the wake of recent advances in network biology, in silico approaches, and omics, this review emphasizes the need to consider conceptually informed research strategies for drug discovery, in the context of the mounting burden posed by chronic neurodegenerative diseases with complex aetiologies and pathophysiologies involving multiple signalling pathways and numerous drug targets.

Benzoxazole/benzothiazole-derived VEGFR-2 inhibitors: Design, synthesis, molecular docking, and anticancer evaluations.

Abstract: A novel series of benzoxazole/benzothiazole derivatives 4a-c-11a-e were designed, synthesized, and evaluated for anticancer activity against HepG2, HCT-116, and MCF-7 cells. HCT-116 was the most sensitive cell line to the influence of the new derivatives. In particular, compound 4c was found to be the most potent derivative against HepG2, HCT-116, and MCF-7 cells, with IC50 values = 9.45 ± 0.8, 5.76 ± 0.4, and 7.36 ± 0.5 µM, respectively. Compounds 4b, 9f, and 9c showed the highest anticancer activities against HepG2 cells with IC50 values of 9.97 ± 0.8, 9.99 ± 0.8, and 11.02 ± 1.0 µM, respectively, HCT-116 cells with IC50 values of 6.99 ± 0.5, 7.44 ± 0.4, and 8.15 ± 0.8 µM, respectively, and MCF-7 cells with IC50 values of 7.89 ± 0.7, 8.24 ± 0.7, and 9.32 ± 0.7 µM, respectively, in comparison with sorafenib as reference drug with IC50 values of 9.18 ± 0.6, 5.47 ± 0.3, and 7.26 ± 0.3 µM, respectively. The most active compounds 4a-c, 9b,c,e,f,h, and 11c,e were further evaluated for their VEGFR-2 inhibition. Compounds 4c and 4b potently inhibited VEGFR-2 at IC50 values of 0.12 ± 0.01 and 0.13 ± 0.02 µM, respectively, which are nearly equipotent to the sorafenib IC50 value (0.10 ± 0.02 µM). Furthermore, molecular docking studies were performed for all synthesized compounds to assess their binding pattern and affinity toward the VEGFR-2 active site.

Synthesis, characterization, molecular docking and biological activities of novel pyrazoline derivatives.

Abstract: In this study, synthesis of ethyl 2-((4-bromophenyl)diazenyl)-3-oxo-phenylpropanoate 1 was carried out and a series of new 3H-pyrazol-3-ones (P1-7) were synthesized from 1 as well as various hydrazines. The obtained yields of the synthesized compounds were moderate (40-70%) and these compounds were confirmed by spectral data. These novel pyrazoline derivatives were effective inhibitor compounds of the human carbonic anhydrase I and II isozymes (hCAs I and II) and of the acetylcholinesterase (AChE) enzyme, with Ki values in the range of 17.4-40.7 nM for hCA I, 16.1-55.2 nM for hCA II, and 48.2-84.1 nM for AChE. In silico studies were performed on the compounds inhibiting hCA I, hCA II, and AChE receptors. On the basis of the findings, the inhibition profile of the new pyrazoline compounds at the receptors was determined.

Discovery and antiproliferative evaluation of new quinoxalines as potential DNA intercalators and topoisomerase II inhibitors.

Abstract: In continuation of our previous work on the design and synthesis of topoisomerase II (Topo II) inhibitors and DNA intercalators, a new series of quinoxaline derivatives were designed and synthesized. The synthesized compounds were evaluated for their cytotoxic activities against a panel of three cancer cell lines (Hep G-2, Hep-2, and Caco-2). Compounds 18b, 19b, 23, 25b, and 26 showed strong potencies against all tested cell lines with IC50 values ranging from 0.26 ± 0.1 to 2.91 ± 0.1 µM, comparable with those of doxorubicin (IC50 values ranging from 0.65 ± 0.1 to 0.81 ± 0.1 µM). The most active compounds were further evaluated for their Topo II inhibitory activities and DNA intercalating affinities. Compounds 19b and 19c exhibited high activities against Topo II (IC50 = 0.97 ± 0.1 and 1.10 ± 0.1 µM, respectively) and bound the DNA at concentrations of 43.51 ± 2.0 and 49.11 ± 1.8 µM, respectively, whereas compound 28b exhibited a significant affinity to bind the DNA with an IC50 value of 37.06 ± 1.8 µM. Moreover, apoptosis and cell-cycle tests of the most promising compound 19b were carried out. It was found that 19b can significantly induce apoptosis in Hep G-2 cells. It has revealed cell-cycle arrest at the G2/M phase. Moreover, compound 19b downregulated the Bcl-2 levels, indicating its potential to enhance apoptosis. Furthermore, molecular docking studies were carried out against the DNA-Topo II complex to examine the binding patterns of the synthesized compounds.

Synthesis, crystal structure, and biological evaluation of optically active 2‐amino‐4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐3‐carbonitriles: Antiepileptic, antidiabetic, and anticholinergics potentials

Abstract: In the presence of chiral organic catalysts, the optically active 4H-chromine was synthesized from the multicomponent condensation of 5,5-dimethylcyclohexane-1,3-dione with malononitrile and methylene-active compound, and the specific angle of rotation of the compounds was determined in the AUTOPOL-III polarimeter and their structures were confirmed by the X-ray spectroscopic analysis method. These optically active 2-amino-4-aryl-7,7-dimethyl-5-oxo-5,6,7,8-tetrahydro-4H-chromen-3-carbonitriles were effective inhibitors of α-glycosidase, the cytosolic carbonic anhydrase I and II isoforms (hCA I and II), and acetylcholinesterase (AChE) enzymes with Ki values in the range of 21.33 ± 1.11 to 40.24 ± 10.78 μM for hCA I, 28.91 ± 6.51 to 59.97 ± 15.62 μM for hCA II, 18.16 ± 3.18 to 66.57 ± 1.36 μM for α-glycosidase, and 8.68 ± 0.93 to 102.61 ± 24.96 μM for AChE.

Potent and highly selective dual-targeting monoamine oxidase-B inhibitors: Fluorinated chalcones of morpholine versus imidazole.

Abstract: Two series of fluorinated chalcones containing morpholine and imidazole-based compounds (f1-f8) were synthesized and evaluated for recombinant human monoamine oxidase (MAO)-A and -B as well as acetylcholinesterase inhibitory activities. Our results indicate that morpholine containing chalcones are highly selective MAO-B inhibitors having reversibility properties. All the imidazole-based fluorinated chalcones showed weak MAO inhibitions in both isoforms. Among the tested compounds, (2E)-3-(3-fluorophenyl)-1-[4-(morpholin-4-yl)phenyl]prop-2-en-1-one (f2) showed potent inhibitory activity for recombinant human MAO-B (IC50 = 0.087 μM) with a high selectivity index (SI) of 517.2. In the recovery experiments using dialysis, the residual activity of MAO-B inhibited by f2 was close to that with the reversible reference inhibitor. Inhibition assays revealed that the Ki values of f1 and f2 for MAO-B were 0.027 and 0.020 μM, respectively, with competitive patterns. All the morpholine-based compounds (f1-f4) showed moderate inhibition toward acetylcholinesterase with IC50 values ranging between 24 and 54 μM. All morpholine-containing compounds exhibit good blood-brain barrier permeation in the PAMPA method. The rational approach regarding the highly selective MAO-B inhibitor f2 was further ascertained by induced fit docking and molecular dynamics simulation studies.

Design, synthesis, in silico ADMET profile and GABA-A docking of novel phthalazines as potent anticonvulsants.

Abstract: A new series of 2-substituted-2,3-dihydrophthalazine-1,4-diones (2- 9) were designed and synthesized to evaluate their anticonvulsant activity. The neurotoxicity was assessed using the rotarod test. Molecular docking was performed for the synthesized compounds to assess their binding affinities as γ-aminobutyric acid A (GABA-A) receptor agonists as a possible mechanism of their anticonvulsant action, to rationalize their anticonvulsant activity in a qualitative way. The data obtained from the molecular modeling was strongly matched with that obtained from the biological screening, which revealed that compounds 5a , 9b , and 9h showed the highest binding affinities toward the GABA-A receptor and also showed the highest anticonvulsant activities with relative potencies of 1.66, 1.63, and 1.61, respectively, compared with diazepam. The most active compounds 5a , 9b , and 9h were further tested against maximal electroshock seizures. Compounds 5a and 9b showed 100% protection at a dose level of 125 µg/kg, while compound 9h exhibited 83.33% protection at the same dose level. A GABA enzymatic assay was performed for these highly active compounds to confirm the obtained results and to explain the possible mechanism for their anticonvulsant action. These agents exerted low neurotoxicity and a high safety margin compared with valproate as a reference drug. Most of our designed compounds exhibited a good ADMET profile.

Synthesis, molecular modeling, in vivo study, and anticancer activity of 1,2,4-triazole containing hydrazide-hydrazones derived from (S)-naproxen.

Abstract: A new series of 1,2,4-triazole containing hydrazide-hydrazones derived from (S)-naproxen ( 7a-m) was synthesized in this study. The structures of these compounds were characterized by spectral (Fourier-transform infrared spectroscopy, 1 H-nuclear magnetic resonance (NMR), 13 C-NMR, and high-resolution electron ionization mass spectrometry) methods. Furthermore, molecular modeling of these compounds was studied on human methionine aminopeptidase-2. All synthesized compounds were screened for anticancer activity against three prostate cancer cell lines (PC3, DU-145, and LNCaP) using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium colorimetric method. Compound 7a showed the best activity against the PC3, DU-145 and LNCaP cancer cell lines with IC50 values of 26.0, 34.5, and 48.8 μM, respectively. Compounds 7b, 7k, and 7m showed anticancer activity against cancer cell lines PC3 and DU-145 with IC50 values of 43.0, 36.5, 29.3 μM and 49.8, 49.1, 31.6 μM, respectively. Compounds 7f and 7g showed anticancer activity against PC3 cells with IC50 values of 43.4 and 34.5 μM, respectively. To assess the biodistribution in mice of IRDye800, dye-labeled compound 7a or 100 μM of free dye was injected intravenously into the mice's tail. In vivo images were taken with in vivo imaging system spectrum device at 60, 120, 180, 240, 300, and 360 min after injection. At the end of 360 min, ex vivo studies were carried out to determine in which organs the dye was accumulated in the urogenital system. Ex vivo studies showed that the accumulation of compound 7a in the prostate is greater than that of the free dye, and it is concluded that compound 7a may be promising for the treatment of prostate cancer.

Towards anticancer fluoroquinolones: A review article

Abstract: Different studies about the anticancer potential of several medically used antibacterial fluoroquinolones have been established. Fluoroquinolone derivatives, like some anti-cancer drugs, such as doxorubicin, can achieve antitumor activity via poisoning of type II human DNA topoisomerases. Interestingly, structural features required for the anticancer activity of quinolones have been determined. Most of the chemical modifications required to convert antibacterially acting fluoroquinolones into their anticancer analogs were at position 7 and the carboxylic group at position 3. This review highlights the antitumor potential of fluoroquinolones in general and summarizes the chemical modifications carried out on fluoroquinolones to become anticancer agents. Moreover, the review gives a quick recap on metal ion chelates with fluoroquinolones and their substantial role in topoisomerase poisoning and antitumor potential improvement. Hence, it should be highly interesting for researchers attempting to design and synthesize novel anticancer fluoroquinolone candidates.

Liposomes actively recognizing the glucose transporter GLUT 1 and integrin α v β 3 for dual-targeting of glioma.

Abstract: The treatment of glioma is a great challenge because of the existence of the blood-brain barrier (BBB). In order to develop an efficient glioma-targeting drug delivery system to greatly improve the brain permeability of anti-cancer drugs and target glioma, a novel glioma-targeted glucose-RGD (Glu-RGD) derivative was designed and synthesized as ligand for preparing liposomes to effectively deliver paclitaxel (PTX) to cross the BBB and target glioma. The liposomes were prepared and characterized for particle size, zeta potential, encapsulation efficiency, release profile, stability, hemolysis, and cell cytotoxicity. Also, the Glu-RGD modified liposomes showed superior targeting ability in in vitro and in vivo evaluation as compared to naked PTX, non-coated, singly modified liposomes and liposomes co-modified by physical blending. The relative uptake efficiency and concentration efficiency were enhanced by 4.41- and 4.72-fold compared to that of naked PTX, respectively. What is more, the Glu-RGD modified liposomes also displayed the maximum accumulation of DiD-loaded liposomes at tumor sites compared to the other groups in in vivo imaging. All the results in vitro and in vivo suggested that Glu-RGD-Lip would be a potential delivery system for PTX to treat integrin αv β3 -overexpressing tumor-bearing mice.

Ursolic acid: Pharmacokinetics process in vitro and in vivo, a mini review.

Abstract: Ursolic acid (UA) is a natural triterpene compound found in various fruits and vegetables. UA has a widespread pharmacologic effect, including antitumor, anti-inflammatory, anti-oxidant, anti-apoptotic, anti-allergy, and anti-carcinogenic effects. UA can be used as an alternative medicine for the treatment and prevention of many diseases. However, the bioavailability of UA by oral administration is low since it is absorbed by the intestine through passive diffusion. Therefore, some novel technologies are used to produce UA preparations that can change the pharmacokinetics process and increase its solubility and bioavailability. At present, pharmacokinetic studies on UA are few. In this paper, we will review the pharmacokinetics features of free UA and some novel UA preparations in vitro and in vivo, in order to provide a reference for rational utilization and drug design of UA.

Aminopyrazole-substituted metallophthalocyanines: Preparation, aggregation behavior, and investigation of metabolic enzymes inhibition properties.

Abstract: The synthesis, characterization, aggregation behavior, theoretical studies, and investigation of antimicrobial, antidiabetic, and anticholinergic properties of 4-(2-(5-amino-4-(4-bromophenyl)-3-methyl-1H-pyrazol-1-yl)ethoxy)phthalonitrile (2) and its soluble aminopyrazole-substituted peripheral metallo (Mn, Co, and Ni)-phthalocyanine complexes (3-5) are reported for the first time. The synthesized compounds and phthalocyanine complexes were characterized spectroscopically. The new phthalonitrile derivative (2) and its peripheral metallophthalocyanine complexes (3-5) were found to be effective inhibitors of α-glycosidase, acetylcholinesterase (AChE), human carbonic anhydrase I and II isoforms (hCA I and II), and butyrylcholinesterase (BChE) with Ki values in the range of 1.55 ± 0.47 to 10.85 ± 3.43 nM for α-glycosidase, 8.44 ± 0.32 to 21.31 ± 7.91 nM for hCA I, 11.73 ± 2.82 to 31.03 ± 4.81 nM for hCA II, 101.62 ± 26.58 to 326.54 ± 89.67 nM for AChE, and 68.68 ± 11.15 to 109.53 ± 19.55 nM for BChE. This is the first study of peripherally substituted phthalocyanines containing an aminopyrazole group as potential carbonic anhydrase enzyme inhibitor. Also, the antimicrobial activities of the synthesized compounds were evaluated against six microorganisms (four bacteria and two Candida species) using the broth microdilution method. The gram-positive bacteria were detected to be more sensitive than gram-negative bacteria and yeasts in the synthesized compounds.

Design, synthesis, biological evaluation, and molecular modeling studies of rhodanine derivatives as pancreatic lipase inhibitors.

Abstract: A series of rhodanine-3-acetic acid derivatives were synthesized via Knoevenagel condensation of rhodanine-3-acetic acid with various substituted aromatic aldehydes. The synthesized derivatives were screened in vitro for understanding the inhibitory potential towards pancreatic lipase (PL), a key enzyme responsible for the digestion of dietary fats. Derivative 8f exhibited a potential inhibitory activity towards PL (IC50 = 5.16 µM), comparable to that of the standard drug, orlistat (0.99 µM). An increase in the density of the aromatic ring resulted in potential PL inhibition. The enzyme kinetics of 8f exhibited a reversible competitive-type inhibition, similar to that of orlistat. Derivative 8f exhibited a MolDock score of -125.19 kcal/mol in docking studies, and the results were in accordance with their PL inhibitory potential. Furthermore, the reactive carbonyl group of 8f existed at a distance adjacent to Ser152 (≈3 A) similar to that of orlistat. Molecular dynamics simulation (10 ns) of the 8f-PL complex revealed a stable binding conformation of 8f in the active site of PL (maximum root mean square displacement of ≈2.25 A). The present study identified novel rhodanine-3-acetic acid derivatives with promising PL inhibitory potential, and further lead optimization might result in potent PL inhibitors.

Discovery and structure–activity relationship of plastoquinone analogs as anticancer agents against chronic myelogenous leukemia cells

Abstract: Two series of amino-1,4-benzoquinones (AQ1-18) based on the structural analogs of plastoquinones were synthesized and the structure-activity relationship against chronic myelogenous leukemia activity was examined. All of the synthesized compounds were tested for their cytotoxic effects on different leukemic cell lines. Of interest, AQ15 exhibited a better selectivity than the reference drug imatinib on cancer cells. Owing to this, AQ15 was selected for a further apoptosis/necrosis evaluation where AQ15-treated K562 cells demonstrated similar apoptotic effects like imatinib-treated cells at their IC50 values. The inhibitory effects of AQ15 and the other three compounds with various activities against eight tyrosine kinases, including ABL1, were investigated. AQ15 showed weak activity against ABL1, and a correlation was observed between the anti-K562 and anti-ABL1 activities. The binding mode of AQ15 into the ATP binding pocket of ABL1 kinase was predicted in silico, showing the formation of some key interactions. In addition, AQ15 was shown to suppress the downstream signaling of BCR-ABL in K562 cells. Finally, AQ15 obviously cleaved DNA in the presence of an iron(II) complex system, indicating that this can be the major mechanism of its antiproliferative action, whereas the mild inhibition of ABL kinase is just in-part mechanism of its overall outstanding cellular activity.

A new series of Schiff base derivatives bearing 1,2,3‐triazole: Design, synthesis, molecular docking, and α‐glucosidase inhibition

Abstract: A series of new Schiff bases bearing 1,2,3-triazole 12a-o was designed, synthesized, and evaluated as α-glucosidase inhibitors. All the synthesized compounds showed promising inhibition against α-glucosidase and were more potent than the standard drug acarbose. The kinetic study on the most potent compound 12n showed that this compound acted as a competitive α-glucosidase inhibitor. The docking study revealed that the synthesized compounds interacted with the important residues in the active site of α-glucosidase.

Quinolone derivatives: Potential anti-HIV agent-development and application.

Abstract: Acquired immune deficiency syndrome (AIDS)/human immunodeficiency virus (HIV) is one of the largest and most devastating public health pandemics throughout the world. The global pandemic of drug-sensitive HIV and the increasing threat from drug-resistant HIV result in an urgent need to develop more effective anti-HIV candidates. Quinolone represents a significant class of privileged heterocycles, and its derivatives possess promising in vitro and in vivo anti-HIV properties. The 4-quinolone elvitegravir has already been approved for the treatment of HIV; thus, quinolone derivatives might be promising candidates with anti-HIV activity. This review emphasizes quinolone derivatives with potential anti-HIV activity, covering articles published between 1992 and 2019. The structure-activity relationship is also discussed to provide insights for further development of more active quinolone derivatives.

Novel acyl thiourea derivatives: Synthesis, antifungal activity, gene toxicity, drug-like and molecular docking screening.

Abstract: Nine novel acyl thioureas were synthesized. Their identities and purities were confirmed by LC-MS spectra; each structure was elucidated by elemental analysis, IR, 1 Н and 13 C NMR spectra. Applying an in vitro screening of their antifungal potential, three substances (3, 5, and 6) could be selected as showing high activity against 11 fungi and 3 Phytophthora strains of phytopathogenic significance. Analysis of gene toxicity with the Salmonella reverse mutagenicity test, as an assessment of drug likeness, lipophilicity, and calculations of frontier molecular orbitals assign a low toxicity profile to these compounds. Molecular docking studies point to 14α-demethylase (CYP51) and N-myristoyltransferase (NMT) as possible fungal targets for growth inhibition. The findings are discussed with respect to structure-activity relationship (SAR).

Antiparasitic activities of new lawsone Mannich bases

Abstract: A series of new lawsone Mannich bases derived from salicylaldehydes or nitrofurfural were prepared and tested for their activities against Leishmania major, Toxoplasma gondii, and Trypanosoma brucei brucei parasites. The hydrochloride salts 5a and 6a of the Mannich bases 2a and 3a, derived from unsubstituted salicylaldehyde and long-chained alkyl amines, were selectively and strongly active against T. gondii cells and appear to be new promising drug candidates against this parasite. Compound 6a showed an even higher activity against T. gondii than the known lawsone Mannich base 1b. Compound 4a, derived from salicylaldehyde and 2-methylaminopyridine, was also distinctly active against T. gondii cells. The derivatives 3a (salicyl derivative), 3b (3,5-dichloro-2-hydroxyphenyl derivative), and 3d (5-nitrofuranyl derivative) as well as the hydrochlorides 6a and 6b were also efficacious against T. b. brucei cells with compounds 3a and 3b being more selective for T. b. brucei over Vero cells when compared with the known control compound 1b. The derivatives 5a, 5c, 6a, and 6c proved to be up to five times more active than 1b against L. major promastigotes and up to four times more efficacious against L. major amastigotes.

Synthesis of novel derivatives of 7,8-dihydro-6H-imidazo[2,1-b][1,3]benzothiazol-5-one and their virus-inhibiting activity against influenza A virus.

Abstract: Influenza remains a highly pathogenic and hardly controlled human infection. The ability of selecting drug-resistant variants necessitates the search and development of novel anti-influenza drugs. Herein, we describe the synthesis and evaluation of a series of novel 2-substituted 7,8-dihydro-6H-imidazo[2,1-b][1,3]benzothiazol-5-ones 3a-k for their virus-inhibiting activity against influenza A virus. The new analogues 3a-k prepared in two steps from commercially available cyclohexane-1,3-diones were fully characterized by their NMR and mass spectral data. Among the new derivatives screened for cytotoxicity and in vitro antiviral activity against influenza virus A/Puerto Rico/8/34 (H1N1) in MDCK cells, three analogues 3i-k containing a thiophene unit were found to exhibit high virus-inhibiting activity (high SI values) and a favorable toxicity profile. The compound 3j (CC50 : >1000 μM, SI = 77) with higher potency is the best anti-influenza hit analogue for further structural optimization and drug development. The most active compounds did not inhibit viral neuraminidase and possess therefore other targets and mechanisms of activity than the currently used neuraminidase inhibitors.

Synthesis and antimicrobial activity of novel 1,2,3-triazole-conjugates of quinazolin-4-ones.

Abstract: A novel series of diethyl{4-[(4-oxoquinazolin-3(4H)-yl)methyl]-1H-1,2,3-triazol-1-yl}alkylphosphonates 9aa-aj and their respective derivatives substituted at C6 of the quinazolinone moiety with a bromine atom (9ba-bj) or a nitro group (9ca-cj) were synthesized and assessed for the antibacterial activity toward selected Gram-positive and Gram-negative bacteria. Their antifungal activity was also screened. Compound 9ac was found to be the most active against Staphylococcus aureus ATCC 6535 (MIC 0.625 mg/mL, MBC 1.25 mg/mL), phosphonates 9ab-ai showed promising activity against Enterococcus faecalis ATCC 29212 (MIC = 0.625 mg/mL, MBC = 1.25 mg/mL), while compounds 9ac-j appeared the most active toward Pseudomonas aeruginosa ATCC 27853 (MIC = 0.625 mg/mL, MBC = 1.25 mg/mL). Antifungal assays of compounds 9aa-aj, 9ba-bj, and 9ca-cj were conducted on Candida albicans ATCC 10231 and Aspergillus brasiliensis ATCC 16404 and revealed noticeable activity of 9aa-aj (MIC = 1.25 mg/mL).

Design, synthesis, and biological evaluation of new pyrazino[1,2-a]benzimidazole derivatives as selective cyclooxygenase (COX-2) inhibitors.

Abstract: A new class of pyrazino[1,2-a]benzimidazole derivatives possessing the SO2 Me pharmacophore at the para position of the C-3 phenyl ring was designed, synthesized, and tested for their cyclooxygenase-2 (COX-2) inhibitory, anti-cancer and anti-platelet aggregation activities. In vitro COX-1/COX-2 inhibition studies showed that 2-(4-methylphenyl)-1-methylene-3-(4-(methylsulfonyl)phenyl)-1,2-dihydropyrazino-[1,2-a]benzimidazole (5g) was the most potent COX-2 inhibitor (IC50 = 0.08 μM) and 2-(3,4,5-trimethoxyphenyl)-1-methylene-3-(4-(methylsulfonyl)phenyl)-1,2-dihydropyrazino-[1,2-a]benzimidazole (5m) had the highest selectivity index (SI > 909). Cytotoxicity of the synthesized compounds was also determined against the MCF-7 cell line. Most compounds were cytotoxic against MCF-7 cells and our results showed that compound 5m exhibited the highest anti-proliferative activity compared to the reference compound, cisplatin. Our data also indicated that compound 5k was the most potent platelet aggregation inhibitor according to aggregometry test results.

Anti-Alzheimer's multitarget-directed ligands with serotonin 5-HT6 antagonist, butyrylcholinesterase inhibitory, and antioxidant activity.

Abstract: Serotonin 5-HT6 receptors, butyrylcholinesterase (BuChE) and oxidative stress are related to the pathophysiology of Alzheimer's disease. Inhibition of BuChE provides symptomatic treatment of the disease and the same effect was demonstrated for 5-HT 6 antagonists in clinical trials. Oxidative stress is regarded as a major and primary factor contributing to the development of Alzheimer's disease; therefore, antioxidant agents may provide a disease-modifying effect. Combining BuChE inhibition, 5-HT 6 antagonism, and antioxidant properties may result in multitarget-directed ligands providing cognition-enhancing properties with neuroprotective activity. On the basis of the screening of the library of 5-HT 6 antagonists against BuChE, we selected two compounds and designed their structural modifications that could lead to improved BuChE inhibitory activity. We synthesized two series of compounds and tested their affinity and functional activity at 5-HT 6 receptors, BuChE inhibitory activity and antioxidant properties. Compound 12 with K i and K b values against 5-HT 6 receptors of 41.8 and 74 nM, respectively, an IC 50 value of 5 µM against BuChE and antioxidant properties exceeding the activity of ascorbic acid is a promising lead structure for further development of anti-Alzheimer's agents.

Synthesis and biological evaluation of novel benzo[c]acridine-diones as potential anticancer agents and tubulin polymerization inhibitors.

Abstract: A new series of novel benzo[c]acridine-diones possessing pharmacophoric elements of antitubulins with central dihydropyridine bridge were designed and synthesized as potential anticancer agents and tubulin polymerization inhibitors. The cytotoxic activity of the synthesized compounds was evaluated against eight cancer cell lines including MCF-7, A2780, HeLa, HepG2, DU145, A549, PC3, and LNCAP cancer cells and normal cells human umbilical vein endothelial cell (HUVEC) through 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay, wherein β-lapachone and combretastatin A-4 were used as positive controls. Some of our compounds (4c and 4g) showed significant cytotoxic activity on cancer cells with IC50 values in the range of 5.23-24.32 μM. None of the synthesized compounds showed significant cytotoxicity on normal HUVEC cells. Among all investigated derivatives, compound 4g showed promising greater antiproliferative activity against all tested cancer cells with the highest sensitivity observed for the PC3 cell line. Results from the flow cytometry analysis of PC3 and MCF-7 cancer cells treated with 4g showed an induced cell-cycle arrest at G2/M, and therefore induced apoptosis which occurred at low concentration of test compound, whereas annexin V-FITC/propidium iodide staining assay in the aforementioned cancer cell lines treated with 4g showed that 4g can cause necrosis in PC3 and MCF-7 cancer cells at higher concentration. Compound 4g proved to be an inhibitor of tubulin polymerization in a mode similar to that of colchicine and in a dose-dependent manner. Molecular docking studies of 4g into the colchicine-binding site of tubulin exhibited a possible mode of interaction between this compound and tubulin.

Click chemistry based regioselective one-pot synthesis of coumarin-3-yl-methyl-1,2,3-triazolyl-1,2,4-triazol-3(4H)-ones as newer potent antitubercular agents.

Abstract: Coumarin-3-yl-methyl-1,2,3-triazolyl-1,2,4-triazol-3(4H)-ones (8k-z) were synthesized via copper(I)-catalyzed azide-alkyne cycloaddition click chemistry. The synthesized hybrid molecules were characterized by spectral studies. Compounds 8k-z were screened for their in vitro anti-TB activity by using the Microplate Alamar Blue assay and for cytotoxicity using the MTT assay. Some of the compounds were found to be most potent against the tested Mycobacterium tuberculosis H37Rv strain with a MIC of 1.60 µg/ml. Further, docking the compounds into the InhA binding pocket showed strong binding interactions and effective overall docking scores were recorded. The drug-likeness and toxicity studies were computed using Molinspiration and Protox, respectively.

Design, synthesis, and evaluation of anticonvulsant activities of benzoxazole derivatives containing the 1,2,4-triazolone moiety.

Abstract: A novel series of benzoxazole derivatives containing 1,2,4-triazolone (5a-m) was designed. These compounds were synthesized in order to screen their anticonvulsant activities by the maximal electroshock seizure (MES) model and the subcutaneous pentylenetetrazole (sc-PTZ) seizure model in mice. The rotarod test was used to evaluate their neurotoxicities. Most of the compounds showed anti-MES activities at 100 and 300 mg/kg. Compound 5f, which showed potential anticonvulsant activity in the MES model with ED50 values of 22.0 mg/kg, was considered as the most promising one in this study. It exhibited greater safety than that of carbamazepine and valproate regarding neurotoxicity. The efficacy of compound 5f in inhibiting the tonic seizures and death induced by the convulsants 3-mercaptopropionic acid and BIC was also verified. In an enzyme-linked immunosorbent assay, compound 5f and the positive drug phenytoin significantly increased the γ-aminobutyric acid (GABA) level in the mouse brain. Further, pretreatment with an inhibitor of the GABA synthesizing enzyme dramatically raised the ED50 value of 5f in the MES model. These results confirmed that the compound 5f plays its anticonvulsive action via regulating the GABA function in the brain. Also, a docking study of the compound 5f in the benzodiazepine (BZD) binding site of the GABAA receptor confirmed possible binding of the compound 5f with BZD receptors.

Gatifloxacin-1,2,3-triazole-isatin hybrids and their antimycobacterial activities.

Abstract: A series of gatifloxacin-1,2,3-triazole-isatin hybrids 8a-l were designed, synthesized, and screened for their in vitro antimycobacterial activity as well as cytotoxicity toward Chinese Hamster Ovary (CHO) cells. The synthesized hybrids showed considerable activity against MTB H37 Rv and two MDR-MTB strains with minimal inhibitory concentration (MIC) of 0.25-8 μg/ml, and the hybrid 8a (MICMTB H37Rv : 0.25 μg/ml and MICMDR-MTB : 0.5 and 1 μg/ml) was found to be most active against the tested strains, which was not inferior to the parent gatifloxacin (MIC: 0.5, 0.25, and 0.5 μg/ml) against all three tested strains, and was ≥128-fold more active than isoniazid (MIC: ≥64 μg/ml) and rifampicin (MIC: >128 μg/ml) against the two MDR-MTB strains. Moreover, hybrid 8a (CC50 : 8.0 μg/ml) also displayed acceptable cytotoxicity toward CHO cells, and the selectivity index was 32. The structure-activity relationship and structure-cytotoxicity relationship were also enriched.

A novel five-step synthetic route to 1,3,4-oxadiazole derivatives with potent α-glucosidase inhibitory potential and their in silico studies.

Abstract: A series of new N-aryl/aralkyl derivatives of 2-methyl-2-{5-(4-chlorophenyl)-1,3,4-oxadiazole-2ylthiol}acetamide were synthesized by successive conversions of 4-chlorobenzoic acid (a) into ethyl 4-chlorobenzoate (1), 4-chlorobenzoylhydrazide (2) and 5-(4-chlorophenyl)-1,3,4-oxadiazole-2-thiol (3), respectively. The required array of compounds (6a-n) was obtained by the reaction of 1,3,4-oxadiazole (3) with various electrophiles (5a-n) in the presence of DMF (N,N-dimethylformamide) and sodium hydroxide at room temperature. The structural determination of these compounds was done by infrared, 1 H-NMR (nuclear magnetic resonance), 13 C-NMR, electron ionization mass spectrometry, and high-resolution electron ionization mass spectrometry analyses. All compounds were evaluated for their α-glucosidase inhibitory potential. Compounds 6a, 6c-e, 6g, and 6i were found to be promising inhibitors of α-glucosidase with IC50 values of 81.72 ± 1.18, 52.73 ± 1.16, 62.62 ± 1.15, 56.34 ± 1.17, 86.35 ± 1.17, 52.63 ± 1.16 µM, respectively. Molecular modeling and ADME (absorption, distribution, metabolism, excretion) predictions supported the findings. The current synthesized library of compounds was achieved by utilizing very common raw materials in such a way that the synthesized compounds may prove to be promising drug leads.

Synthesis of 2-(2-oxo-2H-chromen-4-yl)acetamides as potent acetylcholinesterase inhibitors and molecular insights into binding interactions.

Abstract: Sixteen novel coumarin-based compounds are reported as potent acetylcholinesterase (AChE) inhibitors. The most active compound in this series, 5a (IC50 0.04 ± 0.01 µM), noncompetitively inhibited AChE with a higher potency than tacrine and galantamine. Compounds 5d, 5j, and 5 m showed a moderate antilipid peroxidation activity. The compounds showed cytotoxicity in the same range as the standard drugs in HEK-293 cells. Molecular docking demonstrated that 5a acted as a dual binding site inhibitor. The coumarin moiety occupied the peripheral anionic site and showed π-π interaction with Trp278. The tertiary amino group displayed significant cation-π interaction with Phe329. The aromatic group showed π-π interaction with Trp83 at the catalytic anionic site. The long chain of methylene lay along the gorge interacting with Phe330 via hydrophobic interaction. Molecular docking was applied to postulate the selectivity toward AChE of 5a in comparison with donepezil and tacrine. Structural insights into the selectivity of the coumarin derivatives toward huAChE were explored by molecular docking and 3D QSAR and molecular dynamics simulation for 20 ns. ADMET analysis suggested that the 2-(2-oxo-2H-chromen-4-yl)acetamides showed a good pharmacokinetic profile and no hepatotoxicity. These coumarin derivatives showed high potential for further development as anti-Alzheimer agents.

Design, synthesis, biological evaluation, and molecular dynamics of novel cholinesterase inhibitors as anti‐Alzheimer's agents

Abstract: A series of novel chroman-4-one derivatives were designed and synthesized successfully with good to excellent yield (3a-l). In addition, the obtained products were evaluated for their cholinesterase (ChE) inhibitory activities. The results show that among the various synthesized compounds, analogs bearing the piperidinyl ethoxy side chain with 4-hydroxybenzylidene on the 3-positions of chroman-4-one (3l) showed the most potent activity with respect to acetylcholinesterase (anti-AChE activity; IC50 = 1.18 μM). In addition, the structure-activity relationship was studied and the results revealed that the electron-donating groups on the aryl ring of the 3-benzylidene fragment (3k, 3l) resulted in the designed compounds to be more potent ChE inhibitors in comparison with those having electron-withdrawing groups (3h). In this category, the strongest ChE inhibition was found for the compound containing piperidine as cyclic amine, and a hydroxyl group (for AChE, compound 3l) and fluoro group (for butyrylcholinesterase (BuChE, compound 3i) on the para-position of the aryl ring of the benzylidene group. The molecular docking and dynamics studies of the most potent compounds (3i and 3l against BuChE and AChE, respectively) demonstrated remarkable interactions with the binding pockets of the ChE enzymes and confirmed the results obtained through in vitro experiments.