Insights of tankyrases: A novel target for drug discovery.

Tankyrases are the group of enzymes belonging to a class of Poly (ADP-ribose) polymerase (PARP) recently named ADP-ribosyltransferase (ARTD). The two isoforms of tankyrase i.e. tankyrase1 (TNKS1) and tankyrase2 (TNKS2) were abundantly expressed in various biological functions in telomere regulation, Wnt/ß-catenin signaling pathway, viral replication, endogenous hormone regulation, glucose transport, cherubism disease, erectile dysfunction, and apoptosis. The structural analysis, mechanistic information, in vitro and in vivo studies led identification and development of several classes of tankyrase inhibitors under clinical phases. In the nutshell, this review will drive future research on tankyrase as it enlighten the structural and functional features of TNKS 1 and TNKS 2, different classes of inhibitors with their structure-activity relationship studies, molecular modeling studies, as well as past, current and future perspective of the different class of tankyrase inhibitors.

Synthesis and biological activity of structurally diverse phthalazine derivatives: A systematic review.

Phthalazine, a structurally and pharmacologically versatile nitrogen-containing heterocycle, has gained more attention from medicinal chemists in the design and synthesis of novel drugs owing to its pharmacological potential. In particular, phthalazine scaffold appeared as a pharmacophoric feature numerous drugs exhibiting pharmacological activities, in particular, antidiabetic, anticancer, antihypertensive, antithrombotic, anti-inflammatory, analgesic, antidepressant and antimicrobial activities. This review presents a summary of updated and detailed information on phthalazine as illustrated in both patented and non-patented literature. The reported literature have described the optimal pharmacological characteristics of phthalazine derivatives and highlighted the applicability of phthalazine, as potent scaffold in drug discovery.

Synthesis, biological evaluations and computational studies of N-(3-(-2-(7-Chloroquinolin-2-yl)vinyl) benzylidene)anilines as fungal biofilm inhibitors.

In the present investigation, new chloroquinoline derivatives bearing vinyl benzylidene aniline substituents at 2nd position were synthesized and screed for biofilm inhibitory, antifungal and antibacterial activity. The result of biofilm inhibition of C. albicans suggested that compounds 5j (IC50 value = 51.2 µM) and 5a (IC50 value = 66.2 µM) possess promising antibiofilm inhibition when compared with the standard antifungal drug fluconazole (IC50 = 40.0 µM). Two compounds 5a (MIC = 94.2 µg/mL) and 5f (MIC = 98.8 µg/mL) also exhibited good antifungal activity comparable to standard drug fluconazole (MIC = 50.0 µg/mL). The antibacterial screening against four strains of bacteria viz. E. coli, P. aeruginosa, B. subtilis, and S. aureus suggested their potential antibacterial activity and especially all the compounds except 5g were found more active than the standard drug ciprofloxacin against B. subtilis. To further gain insights into the possible mechanism of these compounds in biofilm inhibition through the agglutinin like protein (Als), molecular docking and molecular dynamics simulation studies were carried out. Molecular modeling studies suggested the clear role in inhibition of this protein and the resulting biofilm inhibitory activity.

Molecular docking, pharmacophore based virtual screening and molecular dynamics studies towards the identification of potential leads for the management of H. pylori.

The enzyme pantothenate synthetase panC is one of the potential new antimicrobial drug targets, but it is poorly characterized in H. pylori. H. pylori infection can cause gastric cancer and the management of H. pylori infection is crucial in various gastric ulcers and gastric cancer. The current study describes the use of innovative drug discovery and design approaches like comparative metabolic pathway analysis (Metacyc), exploration of database of essential genes (DEG), homology modelling, pharmacophore based virtual screening, ADMET studies and molecular dynamics simulations in identifying potential lead compounds for the H. pylori specific panC. The top ranked virtual hits STOCK1N-60270, STOCK1N-63040, STOCK1N-44424 and STOCK1N-63231 can act as templates for synthesis of new H. pylori inhibitors and they hold a promise in the management of gastric cancers caused by H. pylori.

Microwave-assisted synthesis of novel 5-substituted benzylidene amino-2-butyl benzofuran-3-yl-4-methoxyphenyl methanones as antileishmanial and antioxidant agents.

A series of 5-substitutedbenzylideneamino-2-butylbenzofuran-3-yl-4-methoxyphenyl methanones is synthesized and evaluated for antileishmanial and antioxidant activities. Compounds 4f (IC50 = 52.0 ±â€¯0.09 µg/ml), 4h (IC50 = 56.0 ±â€¯0.71 µg/ml) and 4l (IC50 = 59.3 ±â€¯0.55 µg/ml) were shown significant antileishmanial when compared with standard sodium stibogluconate (IC50 = 490.0 ±â€¯1.5 µg/ml). Antioxidant study revealed that compounds 4i (IC50 = 2.44 ±â€¯0.47 µg/ml) and 4l (IC50 = 3.69 ±â€¯0.44 µg/ml) have shown potent comparable activity when compared with standard ascorbic acid (IC50 = 3.31 ±â€¯0.34 µg/ml). Molecular docking study was carried out which replicating results of biological activity in case of initial hits 4f and 4h suggesting that these compounds have a potential to become lead molecules in drug discovery process. In silico ADME study was performed for predicting pharmacokinetic profile of the synthesised antileishmanial agents and expressed good oral drug like behaviour.

Novel 2-(nitrooxy)ethyl 2-(4-(substituted phenyl)-2-((substituted phenyl)amino)thiazol-5-yl)acetate as Anti-inflammatory, Analgesic and Nitric Oxide Releasing Agents: Synthesis and Molecular Docking Studies.

BACKGROUND: Due to the need and adverse effects associated with the available anti-inflammatory agents, an attempt was made to develop the new anti-inflammatory agents with better activity and lesser adverse effects. OBJECTIVE: Synthetic approaches based on chemical modification of NSAIDs have been undertaken with the aim of improving NSAIDs safety profile. METHOD: In the present study, a series of thiazole derivatives (3a-3x) was synthesized and tested for its anti-inflammatory with analgesic and nitric oxide releasing properties. In this work, synthesis of molecules containing substituted diaryl ring on 5-membered thiazole ring with nitric oxide releasing moiety is described. RESULTS: Out of the twenty four synthesized compounds, five compounds showed considerable anti-inflammatory and analgesic activity in comparison with the standard. Most of the synthesized compounds showed considerable nitric oxide-releasing property. The molecular docking study was used to rationalize binding interaction at the active site and the result showed good binding interaction. CONCLUSION: From the results of pharmacological studies, we conclude that the synthesized compounds have not only retained, but showed enhanced anti-inflammatory and analgesic profile.

Antileishmanial potential of fused 5-(pyrazin-2-yl)-4H-1,2,4-triazole-3-thiols: Synthesis, biological evaluations and computational studies.

A series of newer 1,2,4-triazole-3-thiol derivatives 5(a-m) and 6(a-i) containing a triazole fused with pyrazine moiety of pharmacological significance have been synthesized. All the synthesized compounds were screened for their in vitro antileishmanial and antioxidant activities. Compounds 5f (IC50=79.0µM) and 6f (IC50=79.0µM) were shown significant antileishmanial activity when compared with standard sodium stibogluconate (IC50=490.0µM). Compounds 5b (IC50=13.96µM) and 6b (IC50=13.96µM) showed significant antioxidant activity. After performing molecular docking study and analyzing overall binding modes it was found that the synthesized compounds had potential to inhibit L. donovani pteridine reductase 1 enzyme. In silico ADME and metabolic site prediction studies were also held out to set an effective lead candidate for the future antileishmanial and antibacterial drug discovery initiatives.

Mur Ligase Inhibitors as Anti-bacterials: A Comprehensive Review.

Exploring a new target for antibacterial drug discovery has gained much attention because of the emergence of Multidrug Resistance (MDR) strains of bacteria. To overcome this problem the development of novel antibacterial was considered as highest priority task and was one of the biggest challenge since multiple factors were involved. The bacterial peptidoglycan biosynthetic pathway has been well documented in the last few years and has been found to be imperative source for the development of novel antibacterial agents with high target specificity as they are essential for bacterial survival and have no homologs in humans. We have therefore reviewed the process of peptidoglycan biosynthesis which involves various steps like formation of UDP-Nacetylglucosamine (GlcNAc), UDP-N-acetylmuramic acid (MurNAc) and lipid intermediates (Lipid I and Lipid II) which are controlled by various enzymes like GlmS, GlmM, GlmU enzyme, followed by Mur Ligases (MurAMurF) and finally by MraY and MurG respectively. These four amide ligases MurC-MurF can be used as the source for the development of novel multi-target antibacterial agents as they shared and conserved amino acid regions, catalytic mechanisms and structural features. This review begins with the need for novel antibacterial agents and challenges in their development even after the development of bacterial genomic studies. An overview of the peptidoglycan monomer formation, as a source of disparity in this process is presented, followed by detailed discussion of structural and functional aspects of all Mur enzymes and different chemical classes of their inhibitors along with their SAR studies and inhibitory potential. This review finally emphasizes on different patents and novel Mur inhibitors in the development phase.

Bacterial Peptide Deformylase Inhibition of Tetrazole-Substituted Biaryl Acid Analogs: Synthesis, Biological Evaluations, and Molecular Docking Study.

The synthesis and screening of tetrazole-substituted biaryl acid analogs 7a-l as bacterial peptide deformylase (PDF) enzyme inhibitors is reported. The compounds 7e (IC50 value = 5.50 µM) and 7g (IC50 value = 7.25 µM) showed good PDF inhibition activity. The compounds 7e (MIC range = 10.75-11.66 µg/mL) and 7g (MIC range = 8.91-12.83 µg/mL) also showed potent antibacterial activity when compared with the standard ciprofloxacin (MIC range = 25-50 µg/mL). Thus, the active derivatives were not only potent PDF enzyme inhibitors but also efficient antibacterial agents. In order to gain more insight into the binding mode of the compounds with the PDF enzyme, the most active compounds 7e and 7g, the moderately active compound 7k, and the least active compound 7h were docked against the PDF enzyme of Escherichia coli. The docking study of the most active compounds 7e and 7g against the PDF enzyme exhibited good binding properties. Hence, we believe our synthesized compounds 7a-l could serve as reservoir for bacterial PDF inhibitor development.

Biphenyl tetrazole-thiazolidinediones as novel bacterial peptide deformylase inhibitors: Synthesis, biological evaluations and molecular docking study.

Herein, we report the synthesis and screening of biphenyl tetrazole-thiazolidinediones 14(a-j) as bacterial Peptide deformylase (PDF) enzyme inhibitors. The compounds 14b (IC50 value=16.25µM), 14c (IC50 value=18.00µM) and 14h (IC50 value=17.25µM) had shown good PDF inhibition activity. The compounds 14b (MIC range=20.75-35.41µg/mL), 14c (MIC range=19.41-26.00µg/mL) and 14d (MIC range=8.41-8.58µg/mL) had also shown potent antibacterial activity when compared with standard ciprofloxacin (MIC range=25-50µg/mL). Thus, the active derivatives were not only potent PDF inhibitors but also efficient antibacterial agents. In order to gain more insight on the binding mode of the compounds with PDF enzyme, the synthesized compounds 14(a-j) were docked against PDF enzyme of E. coli and compounds exhibited good binding properties. The results suggest that this class of compounds have been potential for development and use in a future as antibacterial drugs.

Design and synthesis of 4'-((5-benzylidene-2,4-dioxothiazolidin-3-yl)methyl)biphenyl-2-carbonitrile analogs as bacterial peptide deformylase inhibitors.

Herein, we report the synthesis and screening of 4'-((5-benzylidene-2,4-dioxothiazolidin-3-yl)methyl)biphenyl-2-carbonitrile analogs 11(a-j) as bacterial peptide deformylase (PDF) enzyme inhibitors. The compounds 11b (IC50 value = 139.28 µm), 11g (IC50 value = 136.18 µm), and 11h (IC50 value = 131.65 µm) had shown good PDF inhibition activity. The compounds 11b (MIC range = 103.36-167.26 µg/mL), 11g (MIC range = 93.75-145.67 µg/mL), and 11h (MIC range = 63.61-126.63 µg/mL) had also shown potent antibacterial activity when compared with standard ampicillin (MIC range = 100.00-250.00 µg/mL). Thus, the active derivatives were not only PDF inhibitors but also efficient antibacterial agents. To gain more insight on the binding mode of the compounds with PDF enzyme, the synthesized compounds 11(a-j) were docked against PDF enzyme of Escherichia coli and compounds exhibited good binding properties. The results suggest that this class of compounds has potential for development and use in future as antibacterial drugs.

Bacterial Peptide deformylase inhibition of cyano substituted biaryl analogs: Synthesis, in vitro biological evaluation, molecular docking study and in silico ADME prediction.

Herein, we report the synthesis and screening of cyano substituted biaryl analogs 5(a-m) as Peptide deformylase (PDF) enzyme inhibitors. The compounds 5a (IC50 value=13.16µM), 5d (IC50 value=15.66µM) and 5j (IC50 value=19.16µM) had shown good PDF inhibition activity. The compounds 5a (MIC range=11.00-15.83µg/mL), 5b (MIC range=23.75-28.50µg/mL) and 5j (MIC range=7.66-16.91µg/mL) had also shown potent antibacterial activity when compared with ciprofloxacin (MIC range=25-50µg/mL). Thus, the active derivatives were not only potent PDF inhibitors but also efficient antibacterial agents. In order to gain more insight on the binding mode of the compounds with PDF, the synthesized compounds 5(a-m) were docked against PDF enzyme of Escherichia coli and compounds exhibited good binding properties. In silico ADME properties of synthesized compounds were also analyzed and showed potential to develop as good oral drug candidates.

Synthesis and antimicrobial evaluation of novel ethyl 2-(2-(4-substituted)acetamido)-4-subtituted-thiazole-5-carboxylate derivatives.

A series of novel molecules containing thiazole ring structure were designed and synthesized. The structures of the synthesized compounds were elucidated and confirmed by (1)H NMR, (13)C NMR, Mass spectrum and the purity was checked through HPLC analysis. Among these synthesized compounds, 3a-3i and 6a-6c were tested for their antimicrobial activity (minimum inhibitory concentration) against a series of strains of Bacillus subtilis, Staphylococcus aureus and Escherichia coli for antibacterial activity and against the strains of Candida albicans, Aspergillus flavus and Aspergillus niger for antifungal activity respectively. The results of the antimicrobial screening data revealed that most of the tested compounds showed moderate to good microbial inhibitions.

Antileishmanial activity of novel indolyl-coumarin hybrids: Design, synthesis, biological evaluation, molecular docking study and in silico ADME prediction.

In present work we have designed and synthesized total twelve novel 3-(3-(1H-indol-3-yl)-3-phenylpropanoyl)-4-hydroxy-2H-chromen-2-one derivatives 13(a-l) using Ho(3+) doped CoFe2O4 nanoparticles as catalyst and evaluated for their potential antileishmanial and antioxidant activities. The compounds 13a, 13d and 13h were found to possess significant antileishmanial activity (IC50 value=95.50, 95.00 and 99.00µg/mL, respectively) when compared to the standard sodium stibogluconate (IC50=490.00 µg/mL). The compounds 13a (IC50=12.40 µg/mL), 13d (IC50=13.49 µg/mL), 13g (IC50=13.24 µg/mL) and 13l (IC50=13.74 µg/mL) had shown good antioxidant activity when compared with standards butylated hydroxy toluene (IC50=16.5 µg/mL) and ascorbic acid (IC50=12.8 µg/mL). After performing molecular docking studies, it was found that compounds 13a and 13d had potential to inhibit pteridine reductase 1 enzyme. In silico ADME pharmacokinetic parameters had shown promising results and none of the synthesized compounds had violated Lipinski's rule of five. Thus, suggesting that compounds from the present series can serve as important gateway for the design and development of new antileishmanial as well as antioxidant agent.

Structure Based Library Design (SBLD) for new 1,4-dihydropyrimidine scaffold as simultaneous COX-1/COX-2 and 5-LOX inhibitors.

The various scaffolds containing 1,4-dihydropyrimidine ring were designed by considering the environment of the active site of COX-1/COX-2 and 5-LOX enzymes. The structure-based library design approach, including the focused library design (Virtual Combinatorial Library Design) and virtual screening was used to select the 1,4-dihydropyrimidine scaffold for simultaneous inhibition of both enzyme pathways (COX-1/COX-2 and 5-LOX). The virtual library on each 1,4-dihydropyrimidine scaffold was enumerated in two alternative ways. In first way, the chemical reagents at R groups were filtered by docking of scaffold with single position substitution, that is, only at R1, or R2, or R3, … Rn on COX-2 enzyme using Glide XP docking mode. The structures that do not dock well were removed and the library was enumerated with filtered chemical reagents. In second alternative way, the single position docking stage was bypassed, and the entire library was enumerated using all chemical reagents by docking on the COX-2 enzyme. The entire library of approximately 15,629 compounds obtained from both ways after screening for drug like properties, were further screened for their binding affinity against COX-1 and 5-LOX enzymes using Virtual Screening Workflow. Finally, 142 hits were obtained and divided into two groups based on their binding affinity for COX-1/COX-2 and for both enzyme pathways (COX-1/COX-2 and 5-LOX). The ten molecules were selected, synthesized and evaluated for their COX-1, COX-2 and 5-LOX inhibiting activity.

Biofilm inhibition of linezolid-like Schiff bases: synthesis, biological activity, molecular docking and in silico ADME prediction.

Herein, we report the synthesis and screening of linezolid-like Schiff bases as inhibitors of biofilm formation. The result of biofilm inhibition of Pseudomonas aeruginosa suggested that compounds 5h (IC50 value=12.97±0.33µM) and 5i (IC50 value=15.63±0.20µM) had more inhibitory activity when compared with standard linezolid (IC50=15.93±0.18µM) without affecting the growth of cells (and thus behave as anti-quorum sensing agents). The compounds 5h (MIC range=2.5-10µg/mL) and 5i (MIC range=3.5-10µg/mL) with 2-chloroquinolinyl and 2-chloro-8-methylquinolinyl motif, respectively, showed antibacterial activity in comparable range of linezolid (MIC range=2-3µg/mL) and were more potent when compared with ciprofloxacin (MIC range=25-50µg/mL). Thus, the active derivatives were not only potent inhibitors of P. aeruginosa biofilm growth but also efficient antibacterial agents. The docking study of most active compounds 5h and 5i against PqsD enzyme of P. aeruginosa exhibited good binding properties. In silico ADME properties of synthesized compounds were also analyzed and showed potential to develop as good oral drug candidates.

Peptide deformylase: a new target in antibacterial, antimalarial and anticancer drug discovery.

Peptide deformylase (PDF) is a class of metalloenzyme responsible for catalyzing the removal of the N-formyl group from N-terminal methionine following translation. PDF inhibitors are moving into new phase of drug development. Initially, PDF was considered as an important target in antibacterial drug discovery; however genome database searches have revealed PDF-like sequences in parasites (P. falciparum) and human, widening the utility of this target in antimalarial and anticancer drug discovery along with antibacterial. Using structural and mechanistic information together with high throughput screening, several types of chemical classes of PDF inhibitors with improved efficacy and specificity have been identified. Various drugs like, GSK-1322322 (Phase II), BB-83698 (Phase I), and LBM-415 (Phase I) have entered into clinical developments. Developments in the field have prompted us to review the current aspects of PDFs, especially their structures, different classes of PDF inhibitors, and molecular modeling studies. In nut shell, this review enlightens PDF as a versatile target along with its inhibitors and future perspectives of different PDF inhibitors.

Microwave assisted synthesis and docking study of N-(2-oxo-2-(4-oxo-2-substituted thiazolidin-3ylamino)ethyl)benzamide derivatives as anticonvulsant agents.

Herewith, we report the design and synthesis of a series of N-(2-oxo-2((4-oxo-2-substituted thiazolidin-3yl)amino)ethyl) benzamide derivatives 7(a-j) under microwave irradiation, based on four component pharmacophoric model to get structural prerequisite indispensable for anticonvulsant activity. The synthesized derivatives were investigated in maximal electroshock seizure (MES), subcutaneous pentylenetetrazole (sc-PTZ) induced seizure and neurotoxicity screening. All the test compounds were administered at a dose of 30, 100 and 300 mg/kg body weight at the time interval of 0.5 h and 4 h. The compounds were also evaluated for behavioral activity and toxicity study. The compound 7 h was found to be most active in MES model. The anticonvulsant screening data shows that 65% of the compounds were found active against MES model when compared to 35% sc-PTZ model. The computational parameter such as docking study, logP determination and ADME prediction were performed to exploit the results.

One pot three components microwave assisted and conventional synthesis of new 3-(4-chloro-2-hydroxyphenyl)-2-(substituted) thiazolidin-4-one as antimicrobial agents.

A one-pot, three-component, microwave assisted and conventional synthesis of new 3-(4-chloro-2-hydroxyphenyl)-2-(substituted) thiazolidin-4-one (4a-n) was carried out by using N,N-dimethylformamide as a solvent with high product yield. Among these synthesized compounds (4f, 4g, 4l and 4m) were found to be a broad spectrum molecule active against all bacterial and fungus strains tested, except fungus Aspergillus niger. Amongst the compounds (4g, 4l and 4m) were found to be more potent than respective standard drugs used in the experiment against Candida albicans, Staphylococcus aureus and Aspergillus flavus, respectively. All synthesized compounds were also tested for their cytotoxic activity against HeLa and MCF-7 cell lines by the sulforhodamine B (SRB) assay. This study shows that all compounds were non-cytotoxic in nature, and confirmed their antimicrobial specificity apart from any general cytotoxicity.

Synthesis, antileishmanial activity and docking study of N'-substitutedbenzylidene-2-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl)acetohydrazides.

A series of N'-substitutedbenzylidene-2-(6,7-dihydrothieno[3,2-c]pyridin-5(4H)-yl)acetohydrazide derivatives is synthesized and evaluated for antileishmanial activity against Leishmania donovani promastigotes. Compounds 9a and 9i were shown significant antileishmanial when compared with standard sodium stilbogluconate. Antimicrobial study revealed that compound 9b has potent as well as broad spectrum antibacterial activity when compared with ampicillin and compound 9e showed promising antifungal activity when compared with miconazole. Also, none of the synthesized compounds showed cytotoxicity up to tested concentration. Further, docking study against pteridine reductase 1 enzyme of L. donovani showed good binding interactions. ADME properties of synthesized compounds were also analyzed and showed potential to develop as good oral drug candidates.