Synthesis, biological evaluation, and docking studies of 3-(substituted)-aryl-5-(9-methyl-3-carbazole)-1H-2-pyrazolines as potent anti-inflammatory and antioxidant agents

Synthesis of novel carbazole hydrazine-carbothioamide scaffold as potent antioxidant, anticancer and antimicrobial agents

BACKGROUND

Carbazole-based molecules containing thiosemicarbazide functional groups are recognized for their diverse biological activities, particularly in enhancing therapeutic anticancer effects through inhibiting crucial pathways. These derivatives also exhibit noteworthy antioxidant properties.

OBJECTIVES

This study aims to synthesize, characterize, and evaluate the antioxidant and anticancer activities of 18 novel carbazole derivatives.

METHODS

The radical scavenging capabilities of the compounds were assessed using the 2,2-diphenyl-1-picrylhydrazyl assay. Antiproliferative activities were evaluated on MCF-7 cancer cell lines through viability assays. Additionally, the modulation of the PI3K/Akt/mTOR pathway, apoptosis/necrosis induction, and cell cycle analysis were conducted for the most promising anticancer agents.

RESULTS

nine compounds showed potent antioxidant activities with IC50 values lower than the positive control acarbose, with compounds 4 h and 4y exhibiting the highest potency (IC50 values of 0.73 and 0.38 µM, respectively). Furthermore, compounds 4o and 4r displayed significant anticancer effects, with IC50 values of 2.02 and 4.99 µM, respectively. Compound 4o, in particular, exhibited promising activity by targeting the PI3K/Akt/mTOR signaling pathway, inhibiting tumor survival, inducing apoptosis, and causing cell cycle arrest in MCF-7 cell lines. Furthermore, compound 4o was showed significant antimicrobial activities against S. aureus and E. coli, and antifungal effect against C. albicans. Its potential to overcome drug resistance through this pathway inhibition highlights its promise as an anticancer agent. Molecular docking simulations supported these findings, revealing favorable binding profiles and interactions within the active sites of the enzymes PI3K, AKT1, and mTOR. Moreover, assessing the druggability of the newly synthesized thiosemicarbazide derivatives demonstrated optimal physicochemical properties, further endorsing their potential as drug candidates.

Acetic Acid-Catalyzed (3 + 2) Cyclization of 2-Aroyl-3-aryl-1,1-dicyanocyclopropanes with Arylhydrazines: To trans-4-Dicyanomethyl-1,3,5-triaryl-4,5-dihydropyrazoles

Acetic acid-catalyzed (3 + 2) cyclization reaction of substituted 2-aroyl-3-aryl-1,1-dicyanocyclopropanes with arylhydrazines was investigated for the efficient synthesis of 4-dicyanomethyl-1,3,5-triaryl-4,5-dihydropyrazoles in good yields, in which 4,5-double substituents are predominantly trans selective. This approach included the consecutive condensation, ring opening, and double nucleophilic cyclization reaction.

Design of N-heterocycle based-phthalonitrile/metal phthalocyanine-silver nanoconjugates for cancer therapies

This study reports the anticancer properties of carbazole-containing phthalonitrile/phthalocyanine-modified silver nanoparticles for the first time. In this study, a new mono-substituted phthalonitrile namely 3-[9H-carbazole-9-ethoxy]phthalonitrile and its metal phthalocyanines {M = Zn, Co, and Mn(Cl)} were synthesized by template cyclotetramerization of phthalonitrile derivatives. The newly synthesized compounds were characterized using UV-vis, FT-IR, 1H NMR, 13C NMR, and mass spectroscopy. The resultant compounds were successfully linked to the surface of silver nanoparticles. The characterization of the surficial modification was carried out by applying the TEM technique. The cytotoxic activities of the studied nanoconjugates were tested against A549, DLD-1, and Wi38 cell lines by performing a (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay with/without irradiation. Although the functionalization of silver nanoparticles increased the solubility of phthalocyanines in aqueous media, the presence of phthalonitrile/phthalocyanine derivatives on the silver nanoparticles' surface improved their biological properties. All the studied biological candidates exhibited antiproliferative activities against the cell lines. The IC50 values calculated were between 6.80 and 97.99 μM against the studied cell lines in the dark. However, the IC50 values determined were between 3.11 and 88.90 μM with irradiation. The highest IC50 values obtained were 3.11 and 3.52 μM against the DLD-1 cell line for nanoconjugates 1-AgNP and 3-AgNP, respectively. The findings indicated that the compounds may be utilized as anticancer agents after further studies.

Design, synthesis, X-ray crystal structures, anticancer, DNA binding, and molecular modelling studies of pyrazole-pyrazoline hybrid derivatives

We have designed and synthesized three pyrazole analogs (4, 5a, 5b), pyrazole-based chalcones (6a-6d) and (8a-8h), and N-formyl/acetyl 1,3,5-trisubstituted pyrazoline analogs (7a-7d), (9a-9d). FT-IR, 1H, 13C NMR, and mass spectrometry techniques were used to describe the structures of all the synthesized analogs. The single crystal X-ray method was used to identify the molecular structure of derivatives 4 and 5a. All synthesized analogs were screened by MTT assay on two cancer cell lines, the human lung cancer cell line (A549) and cervical cancer cell line (HeLa). Among all compounds, analog 9d demonstrates significant anticancer activity against HeLa (IC50 = 23.6 μM) and A549 (IC50 = 37.59 μM). The non-interactive interaction of active compound (9d) with Calf thymus DNA (Ct-DNA) has been investigated through various methods, such as UV-vis absorption, emission, cyclic voltammetry and circular dichroism. The DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical has been used to measure the antioxidant capacity of the pyrazoline derivative (9d). The outcomes showed that active analog has significant antioxidant activity. In addition, MD simulation of the EGFR tyrosine kinase protein-ligand complex was performed at a time scale of 100 ns. The MMGBSA data of ligand-protein complex are showed stable interactions up to 100 ns.

Repurposing anti-inflammatory drugs for fighting planktonic and biofilm growth. New carbazole derivatives based on the NSAID carprofen: synthesis, in silico and in vitro bioevaluation

Introduction

One of the promising leads for the rapid discovery of alternative antimicrobial agents is to repurpose other drugs, such as nonsteroidal anti-inflammatory agents (NSAIDs) for fighting bacterial infections and antimicrobial resistance.

Methods

A series of new carbazole derivatives based on the readily available anti-inflammatory drug carprofen has been obtained by nitration, halogenation and N-alkylation of carprofen and its esters. The structures of these carbazole compounds were assigned by NMR and IR spectroscopy. Regioselective electrophilic substitution by nitration and halogenation at the carbazole ring was assigned from H NMR spectra. The single crystal X-ray structures of two representative derivatives obtained by dibromination of carprofen, were also determined. The total antioxidant capacity (TAC) was measured using the DPPH method. The antimicrobial activity assay was performed using quantitative methods, allowing establishment of the minimal inhibitory/bactericidal/biofilm eradication concentrations (MIC/MBC/MBEC) on Gram-positive (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) strains. Computational assays have been performed to assess the drug- and lead-likeness, pharmacokinetics (ADME-Tox) and pharmacogenomics profiles.

Results and discussion

The crystal X-ray structures of 3,8-dibromocarprofen and its methyl ester have revealed significant differences in their supramolecular assemblies. The most active antioxidant compound was 1i, bearing one chlorine and two bromine atoms, as well as the CO2Me group. Among the tested derivatives, 1h bearing one chlorine and two bromine atoms has exhibited the widest antibacterial spectrum and the most intensive inhibitory activity, especially against the Gram-positive strains, in planktonic and biofilm growth state. The compounds 1a (bearing one chlorine, one NO2 and one CO2Me group) and 1i (bearing one chlorine, two bromine atoms and a CO2Me group) exhibited the best antibiofilm activity in the case of the P. aeruginosa strain. Moreover, these compounds comply with the drug-likeness rules, have good oral bioavailability and are not carcinogenic or mutagenic. The results demonstrate that these new carbazole derivatives have a molecular profile which deserves to be explored further for the development of novel antibacterial and antibiofilm agents.

In vivo anticoccidial, antioxidant, and anti-inflammatory activities of avocado fruit, Persea americana (Lauraceae), against Eimeria papillata infection

Apicomplexan parasites, especially Eimeria sp., are the main intestinal murine pathogens, that lead to severe injuries to farm and domestic animals. Many anticoccidial drugs are available for coccidiosis, which, leads to the development of drug-resistant parasites. Recently, natural products are considered as an alternative agent to control coccidiosis. This study was designed to evaluate the anticoccidial activity of the Persea americana fruit extract (PAFE) in male C57BL/6 mice. A total of 35 male mice were divided into seven equal groups (1, 2, 3, 4, 5, 6, and 7). At day 0, all groups except the first group which served as uninfected-untreated control were infected orally with 1 × 10³E. papillata sporulated oocysts. Group 2 served as uninfected-treated control. Group 3 was considered an infected-untreated group. After 60 min of infection, groups 4, 5, and 6 were treated with oral doses of PAFE aqueous methanolic extract (100, 300, and 500 mg/kg of body weight, respectively). Group 7 was treated with amprolium (a reference drug for coccidiosis). PAFE with 500 mg/kg, was the most effective dose, inducing a significant reduction in the output of oocysts in mice feces (by about 85.41%), accompanied by a significant decrease in the number of the developmental parasite stages and a significant elevation of the goblet cells in the jejunal tissues. Upon treatment, a significant change in the oxidative status due to E. papillata infection was observed, where the levels of glutathione (GSH) increased, while, levels of malondialdehyde (MDA) and nitric oxide (NO) were decreased. In addition, the infection significantly upregulated the inflammatory cytokines of interleukin-1β (IL-1β), tumor necrosis factor-alpha (TNF-α), and interferon-γ (IFN-γ). This increase in mRNA expression of IL-1β, TNF-α, and IFN-γ was about 8.3, 10.6, and 4.5-fold, respectively, which significantly downregulated upon treatment. Collectively, P. americana is a promising medicinal plant with anticoccidial, antioxidant, and anti-inflammatory activities and could be used for the treatment of coccidiosis.

Synthesis of indole-based oxadiazoles and their interaction with bacterial peptidoglycan and SARS-CoV-2 main protease: In vitro, molecular docking and in silico ADME/Tox study

In the present study, Indole-based-oxadiazole (1A-17A) compounds were successfully synthesized. The structures of all synthesized compounds were fully characterized by different sophisticated spectroscopic techniques such 1H NMR, 13C NMR, and HREI-MS. Further, the synthesized compounds were explored to investigate their broad-spectrum antibacterial and antibiofilm potential against multidrug resistant Pseudomonas aeruginosa (MDR-PA) and methicillin resistant Staphylococcus aureus (MRSA). The compounds possessed a broad spectrum of antibacterial activity having MIC values of values 1–8 mg/ml against the tested microorganisms. Compound A6 and A7 shows maximum antibacterial activity against MDR-PA, whereas A6, A7 and A11 shows highest activity against MRSA. Furthermore, antibiofilm assay shows that A6, A7 and A11 showed maximum inhibition of biofilm formation and it was found that at 4 mg/ml; A6, A7 and A11 inhibit MRSA biofilm formation by 81.1, 77.5 and 75.9%, respectively; whereas in case of P. aeruginosa; A6 and A7 showed maximum biofilm inhibition and inhibit biofilm formation by 81.5 and 73.7%, respectively. Molecular docking study showed that compounds A6, A7, A8, A10, and A11 had high binding affinity to bacterial peptidoglycan, indicating their potential inhibitory activity against tested bacteria, whereas A6 and A11 were found to be the most effective inhibitors of SARS CoV-2 main protease (3CLpro), with a binding affinity of − 7.78 kcal/mol. Furthermore, SwissADME and pkCSM-pharmacokinetics online tools was applied to calculate the ADME/Tox profile of the synthesized compounds and the toxicity of these chemicals was found to be low. The Lipinski, Veber, Ghose, and Consensus LogP criteria were also used to predict drug-likeness levels of the compounds. Our findings imply that the synthesized compounds could be a useful for the preventing and treating biofilm-related microbial infection as well as SARS-CoV2 infections.

Synthesis, electrochemical, optical and biological properties of new carbazole derivatives

Carbazole skeleton is the key structural motif of many biologically active compounds including synthetic and natural products. Based on the (E)-2-(2-(4-9H-carbazol-9-yl)benzylidene) hydrazinyl)thiazole as skeleton, three novel carbazole dyes were synthesized. The scientific analysis includes the effect of changing the strength of the activating substituents and their exchange for the deactivating substituent on the chemical and biological properties. The presented research showed a significant influence of the CH₃, OCH₃ and CH₂COOC₂H₅ groups on the spectral properties of the tested derivatives. Their significant influence is also visible in electrochemical, nonlinear-optic and biological properties. The study also included the analysis of the use of the presented derivatives as potential fluorescent probes for in vivo and in vitro tests. Quantum-chemical calculations complement the conducted experiments.

Design, synthesis, and SAR study of novel 4,5-dihydropyrazole-Thiazole derivatives with anti-inflammatory activities for the treatment of sepsis

Systemic inflammatory response syndrome is a major feature of sepsis which is one of the major causes of death worldwide. It has been reported that 3,5-diaryl-4,5-dihydropyrazole and thiazole derivatives have many biological functions, especially in the aspect of anti-inflammation. According to the strategy of pharmacophore combination, we introduced thiazole moiety into dihydropyrazole skeleton to design and synthesize a novel series of 2-(3,5-diphenyl-4,5-dihydro-1H-pyrazol-1-yl)-4-methylthiazole derivatives, and evaluated their anti-inflammatory activities for sepsis treatment. Preliminary structure-activity relationship (SAR) analysis was conducted by their inhibitory activities against nitric oxide (NO) release in LPS-induced RAW264.7 cells, and the optimal compound E26 exhibited more potent anti-inflammatory activity than the positive control treatment indomethacin and dexamethasone. In further mechanism study, our results showed that compound E26 significantly suppressed the production of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), NO and inhibited the expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) through blocking MAPKs signaling pathway. In addition, in vivo administration of compound E26 resulted in a significant improvement of LPS-induced sepsis in C57BL/6J mice, with reducing toxicity in multiple organs. Taken together, this study demonstrated the compound E26 could be a promising agent for the treatment of sepsis.

Rational Design of Dipicolylamine-Containing Carbazole Amphiphiles Combined with Zn2+ as Potent Broad-Spectrum Antibacterial Agents with a Membrane-Disruptive Mechanism

Antibiotic resistance has become one of the most urgently important problems facing healthcare providers. A novel series of dipicolylamine-containing carbazole amphiphiles with strong Zn²⁺ chelating ability were synthesized, biomimicking cationic antimicrobial peptides. Effective broad-spectrum 16 combined with 12.5 μg/mL Zn²⁺ was identified as the most promising antimicrobial candidate. 16 combined with 12.5 μg/mL Zn²⁺ exhibited excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria (MICs = 0.78-3.125 μg/mL), weak hemolytic activity, and low cytotoxicity. Time-kill kinetics and mechanism studies revealed 16 combined with 12.5 μg/mL Zn²⁺ had rapid bacterial killing properties, as evidenced by disruption of the integrity of bacterial cell membranes, effectively preventing bacterial resistance development. Importantly, 16 combined with 12.5 μg/mL Zn²⁺ showed excellent in vivo efficacy in a murine keratitis model caused by Staphylococcus aureus ATCC29213 or Pseudomonas aeruginosa ATCC9027. Therefore, 16 combined with 12.5 μg/mL Zn²⁺ could be a promising candidate for treating bacterial infections.

A Comprehensive Review of Monoamine Oxidase-A Inhibitors in their Syntheses and Potencies

BACKGROUND

Monoamine oxidases (MAOs) play a crucial role during the development of various neurodegenerative disorders. There are two MAO isozymes, MAO-A and MAO-B. MAO-A is a flavoenzyme, which binds to the outer mitochondrial membrane and catalyzes the oxidative transformations of neurotransmitters like serotonin, norepinephrine, and dopamine.

MATERIALS AND METHODS

Focus on synthetic studies has culminated in the preparation of many MAOA inhibitors, and advancements in combinatorial and parallel synthesis have accelerated the developments of synthetic schemes. Here, we provided an overview of the synthetic protocols employed to prepare different classes of MAO-A inhibitors. We classified these inhibitors according to their molecular scaffolds and the synthetic methods used.

RESULTS

Various synthetic and natural derivatives from a different class of MAO-A inhibitors were reported.

CONCLUSION

The review provides a valuable tool for the development of a new class of various selective MAO-A inhibitors for the treatment of depression and other anxiety disorders.

Identification of an orally active carbazole aminoalcohol derivative with broad-spectrum anti-animal trypanosomiasis activity

Animal trypanosomiasis, caused by the members of subgenus Trypanozoon (Trypanosoma brucei brucei, T. evansi and T. equiperdum), has reduced animal productivity leading to significant negative economic impacts in endemic regions. Due to limited drug discovery and the emergence of drug-resistance over many recent decades, novel and effective compounds against animal trypanosomiasis are urgently required. This study was conducted to evaluate the antitrypanosomal potential of a batch of carbazole aminoalcohol derivatives. Among them, we found that the most effective compound was H1402, which exhibited potent trypanocidal efficacy against the bloodstream-form of T. b. brucei (EC₅₀ = 0.73 ± 0.05 µM) and presented low cytotoxicity against two mammalian cell lines with CC₅₀ > 30 µM. Using a murine model of acute infection, oral administration with H1402 demonstrated a complete clearance of T. b. brucei and all the infected mice were cured when they were treated twice daily for 5 days at a dose of 100 mg/kg. Furthermore, parasites were not detected in mice infected with T. evansi and T. equiperdum (the causative agents of surra and dourine, respectively, in animals) within 30 days following the same regimen with H1402. In addition, H1402 caused severe morphological and ultrastructural destruction to trypanosomes, as well as causing phosphatidylserine externalization, which are suggested to be the most likely cause of cell death. Overall, the present data demonstrated that H1402 could be promising as a rapid, safe and orally active lead compound for the development of new chemotherapeutics for animal trypanosomiasis.

Effect of the Chloro-Substitution on Electrochemical and Optical Properties of New Carbazole Dyes

Carbazole derivatives are the structural key of many biologically active substances, including naturally occurring and synthetic ones. Three novel (E)-2-(2-(4-9H-carbazol-9-yl)benzylidene)hydrazinyl)triazole dyes were synthesized with different numbers of chlorine substituents attached at different locations. The presented research has shown the influence of the number and position of attachment of chlorine substituents on electrochemical, optical, nonlinear, and biological properties. The study also included the analysis of the use of the presented derivatives as potential fluorescent probes for in vivo and in vitro tests. Quantum-chemical calculations complement the conducted experiments.

Novel quinolinone-pyrazoline hybrids: synthesis and evaluation of antioxidant and lipoxygenase inhibitory activity

The present project deals with the investigation of structure-activity relationship of several quinolinone-chalcone and quinolinone-pyrazoline hybrids, in an effort to discover promising antioxidant and anti-inflammatory agents. In order to accomplish this goal, four bioactive hybrid quinolinone-chalcone compounds (8a-8d) were synthesized via an aldol condensation reaction, which were then chemically modified, forming fifteen new pyrazoline analogues (9a-9o). All the synthesized analogues were in vitro evaluated in terms of their antioxidant and soybean lipoxygenase (LOX) inhibitory activity. Among all the pyrazoline derivatives, compounds 9b and 9m were found to possess the best combined activity, whereas 9b analogue exhibited the most potent LOX inhibitory activity, with IC50 value 10 μM. The in silico docking results revealed that the synthetic pyrazoline analogue 9b showed high AutoDock Vina score (- 10.3 kcal/mol), while all the tested derivatives presented allosteric interactions with the enzyme.

Contemporary advances of cyclic molecules proposed for inflammation

This review stretches insight about the advancement (2011-2021) of synthesized non-heterocyclic, heterocyclic and natural occurring cyclic molecules for inflammation. While inflammation is very significant in the abolition of pathogens and other causes of soreness, a protracted inflammatory procedure takes to outcomes in chronic disease that might finally affect in organ failure or damage. Thus, restraining the provocative process by the use of anti-inflammatory agents is chief in controlling this damage. It also reveals other pursuit along with their anti-inflammatory activity. Molecular docking studies represent most suitable PDB (Protein Data Bank) ID for the synthesized heterocyclic molecules with their selective inhibitor. It discusses the findings presented in recent research papers and provides understanding to researchers intended for the growth of newer combinations/molecules having littler side things.

Discovery of Anticancer Agents from 2-Pyrazoline-Based Compounds

As nitrogen-containing five-membered heterocyclic structural units, the substituted pyrazole derivatives have a broad spectrum of pharmacological activities, especially 4,5-dihydro-1H-pyrazoles that also commonly known as 2-pyrazolines. Since 2010, considerable studies have been found that the 2-pyrazoline derivatives possess potent anticancer activities. In the present review, it covers the pyrazoline derivatives reported by literature from 2010 till date (2010-2019). This review aims to establish the relationship between the anticancer activities variation and different substituents introduced into a 2-pyrazoline core, which could provide important pharmacophore clues for the discovery of new anticancer agents containing 2-pyrazoline scaffold.

Investigation of in vitro and in silico effects of some novel carbazole Schiff bases on human carbonic anhydrase isoforms I and II

Carbonic anhydrases (CAs, EC4.2.1.1) are metalloenzymes that catalyse reversible hydration reaction of carbon dioxide to bicarbonate and protons. In recent years, there has been a great interest in inhibitors/activators of carbonic anhydrase isoenzymes. Therefore, we investigated the effects of four different carbazole Schiff base derivatives, which are believed to have a potential to be used as a drug, on human carbonic anhydrase (hCA) isoenzymes I and II under in vitro conditions. The IC₅₀ values of carbazole Schiff base derivatives were found to be in the range of 32.09-151.2 μM for hCA isoenzyme I and 21.82-40.54 μM for hCA isoenzyme II. Among all compounds, (E)-3-(((9-Octyl-9H-carbazole-3-yl)imino)methyl)benzene-1,2-diol (C3) had the strongest inhibitory effect on hCA isoenzyme II. It was determined that 2,3,4-trimethoxy and 4-hydroxy phenyl containing carbazole compounds have selective inhibition against hCA II isoenzyme. Docking studies were performed against hCA I and II receptors using induced-fit docking method. The compounds had affinity scores varying from -7.74 ± 0.27 to -6.27 ± 0.07 kcal/mol for hCA I and from -8.04 ± 0.17 to -7.27 ± 0.18 kcal/mol for hCA II.Communicated by Ramaswamy H. Sarma.

Synthesis and Biological Evaluation of 1,3,5-Trisubstituted 2-Pyrazolines as Novel Cyclooxygenase-2 Inhibitors with Antiproliferative Activity

A new series of 1,3,5-trisubstituted 2-pyrazolines for the inhibition of cyclooxygenase-2 (COX-2) were synthesized. The designed structures include a COX-2 pharmacophore SO₂ CH₃ at the para-position of the phenyl ring located at C-5 of a pyrazoline scaffold. The synthesized compounds were tested for in vitro COX-1/COX-2 inhibition and cell toxicity against human colorectal adenocarcinoma cell lines HT-29. The lead compound (4-chlorophenyl){5-[4-(methanesulfonyl)phenyl]-3-phenyl-4,5-dihydro-1H-pyrazol-1-yl}methanone (16) showed significant COX-2 inhibition (IC₅₀ =0.05±0.01 μM), and antiproliferative activity (IC₅₀ =5.46±4.71 μM). Molecular docking studies showed that new pyrazoline-based compounds interact via multiple hydrophobic and hydrogen-bond interactions with key binding site residues of the COX-2 enzyme.

Design, synthesis and evaluation of carbazole derivatives as potential antimicrobial agents

Five series of novel carbazole derivatives containing an aminoguanidine, dihydrotriazine, thiosemicarbazide, semicarbazide or isonicotinic moiety were designed, synthesised and evaluated for their antimicrobial activities. Most of the compounds exhibited potent inhibitory activities towards different bacterial strains (including one multidrug-resistant clinical isolate) and one fungal strain with minimum inhibitory concentrations (MICs) between 0.5 and 16 µg/ml. Compounds 8f and 9d showed the most potent inhibitory activities (MICs of 0.5–2 µg/ml). Furthermore, compounds 8b, 8d, 8f, 8k, 9b and 9e with antimicrobial activities were not cytotoxic to human gastric cancer cell lines (SGC-7901 and AGS) or a normal human liver cell line (L-02). Structure–activity relationship analyses and docking studies implicated the dihydrotriazine group in increasing the antimicrobial potency and reducing the toxicity of the carbazole compounds. In vitro enzyme activity assays suggested that compound 8f binding to dihydrofolate reductase might account for the antimicrobial effect.

Jejucarbazoles A–C, carbazole glycosides with indoleamine 2,3-dioxygenase 1 inhibitory activity from Streptomyces sp. KCB15JA151

A bioassay-guided investigation led to the isolation of three new carbazole glycosides, jejucarbazoles A–C (1–3), from Streptomyces sp. KCB15JA151. Their planar structures were elucidated by detailed NMR and MS spectroscopic analysis with a literature study. Their relative and absolute configurations were established by ROESY correlations, coupling constants, LC-MS analysis of thiocarbamoyl-thiazolidine carboxylate derivatives, and ECD calculation. Compounds 1–3 showed indoleamine 2,3-dioxygenase 1 (IDO1) inhibitory activity with IC₅₀ values of 18.38, 9.17, and 8.81 μM. The molecular docking analysis suggested that all compounds act as heme-displacing inhibitors against IDO1 enzyme.

This study presents the isolation and structure elucidation of jejucarbazoles A–C, isolated from Streptomyces sp. KCB15JA15 and their inhibitory effect and molecular docking analysis against the IDO1 enzyme.

Synthesis of carbazole based α-aminophosphonate derivatives: design, molecular docking and in vitro cholinesterase activity

A series of novel carbazole based α-aminophosphonate derivatives were synthesized under solvent-free condition, characterized and evaluated for their cholinesterase inhibition, enzyme kinetic inhibition, in-vitro cell viability using N2a cells, neuroprotective studies against H₂O₂-induced stress using N2a cells and antioxidant studies using DPPH radical activity. Test compounds displayed better AChE activity (0.475 to 7.781 µM) than BuChE (3.306 to 21.32 µM). Compound 4j was most potent derivative against AChE as well as BuChE with IC₅₀=0.475 ± 0.12 µM and IC₅₀=3.306 ± 0.21 µM respectively. Kinetic inhibition studies indicate that compound 4j exhibits mixed type inhibition against both enzymes which was supported by molecular docking studies. Cell viability studies showed that compounds did not induce any cytotoxic effect against N2a cells using MTT assay. Also, compound 4j, 4 s and 4r were subjected to H₂O₂-induced stress using N2a cells and were found to be protective in nature. ADME predictions were carried out to understand the pharmacokinetics behaviour.Communicated by Ramaswamy H. Sarma.

Synthesis and antioxidant properties of 2-(3-(hydroxyimino)methyl)-1H-indol-1-yl)acetamide derivatives

Background

The main aim of this work was to synthesise a novel N-(substituted phenyl)-2-(3-(hydroxyimino) methyl)-1H-indol-1-yl) acetamide derivatives and evaluate their antioxidant activity. These compounds were prepared by a condensation reaction between 1H-indole carbaldehyde oxime and 2-chloro acetamide derivatives. The newly synthesised compound structures were characterised by FT-IR, 1H-NMR, mass spectroscopy and elemental analysis. Furthermore, the above-mentioned compounds were screened for antioxidant activity by using ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods.

Result

The antioxidant activity result reveals that most of the compounds were exhibiting considerable activity in both methods and the values are very closer to the standards. Among the synthesised compounds, compound 3j, 3a and 3k were shown remarkable activity at low concentration.

Conclusion

Compounds 3j, 3a and 3k were shown highest activity among the prepared analogues due to the attachment of halogens connected at the appropriate place in the phenyl ring. Hence, these substituted phenyl rings considered as a perfect side chain for the indole nucleus for the development of the new antioxidant agents.

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.

Metal-Free Indole-Phenacyl Bromide Cyclization: A Regioselective Synthesis of 3,5-Diarylcarbazoles

A metal-free, simultaneous triple C-C coupling cyclization reaction between phenacyl bromides and indoles is discovered in a highly regioselective fashion to furnish 3,5-diarylcarbazoles. DMAP is utilized as the only reagent for the unusual and rapid cyclization reaction to furnish all new carbazole compounds through installation of a great diversity of substituents. A plausible radical mechanism for the new reaction is predicted by conducting various control experiments, competitive reactions, furoindole formation, and ESI-MS analyses of the ongoing cyclization reaction.

POCl3 Mediated Syntheses, Pharmacological Evaluation and Molecular Docking Studies of Some Novel Benzofused Thiazole Derivatives as a Potential Antioxidant and Anti-inflammatory Agents

Background:

The present research work is focused on the development of alternative antioxidant and anti-inflammatory agents. The review of the literature reveals that many benzofused thiazole analogues have been used as lead molecules for the design and development of therapeutic agent, including anticancer, anti-inflammatory, antioxidant and antiviral. The synthesized benzofused thiazole derivatives are evaluated for in vitro antioxidant, anti-inflammatory activities and molecular docking study. Thus, the present research work aims to synthesize benzofused thiazole derivatives and to test their antioxidant and antiinflammatory activities.

Objective:

To design and synthesize an alternative antioxidant and anti-inflammatory agents.

Methods:

The substituted benzofused thiazoles 3a-g were prepared by cyclocondensation reaction of appropriate carboxylic acid with 2-aminothiophenol in POCl3 and heated for about 2-3 h to offer benzofused thiazole derivatives 3a-g. All the newly synthesized compounds were in vitro screened for their anti-inflammatory and antioxidant activities by using a known literature method.

Results:

At the outset, the study of in vitro indicated that the compounds code 3c, 3d and 3e possessed distinct anti-inflammatory activity as compared to a standard reference. All the tested compounds show potential antioxidant activity against one or more reactive (H2O2, DPPH, SO and NO) radical scavenging species. Additionally, docking simulation is further performed to the position of compounds 3d & 3e into the anti-inflammatory active site to determine the probable binding model.

Conclusion:

New anti-inflammatory and antioxidant agents were needed; it has been proved that benzofused thiazole derivatives were 3c, 3d and 3e constituted as an interesting template for the evaluation of new anti-inflammatory agents and an antioxidant’s work also may provide an interesting template for further development.

N-Trifluoroacetylated pyrazolines: Synthesis, characterization and antimicrobial studies

A series of N-trifluoroacetyl-2-pyrazolines have been synthesized via cyclization of chalcones in the presence of trifluoroacetic acid and hydrazine as a base. The method used for the preparation of pyrazolines was found to be an efficient one as all of the compounds were obtained in good yield (up to 79%). Various spectroscopic techniques established the structures and additionally corroborated the compounds 2a and 2e by single crystal X-ray. Newly synthesized pyrazolines were investigated for their potential as antimicrobial agents. Compound 2a displayed promising antimicrobial activity against pathogenic Escherichia coli and Pseudomonas aeruginosa. Furthermore, the mechanism of the antimicrobial activity of 2a was demonstrated with the help of scanning electron microscopy (SEM), which revealed complete damage of the bacterial cell membrane, providing dead cell debris in the milieu. The minimum inhibitory concentration (MIC) observed was 79 and 90 µM against E. coli and P. aeruginosa, respectively. Hence, these compounds might be significantly useful in antimicrobial drug development.

Synthesis and biological studies of amphiphilic carbazole pyridinium conjugates

Amphiphilic carbazole pyridinium conjugates are synthesized and characterized by IR, 1H and [Formula: see text]C NMR and ESI-MS spectrometry. The pyridinium group is attached on the 3-position of the carbazole ring and long alkyl chains are linked to the central [Formula: see text] atom. The introduction of a pyridinium group afforded water-soluble carbazole derivatives with significant bathochromic shifts in their absorption and emission spectra. As compared to the parent [Formula: see text]-butylcarbazole compound, carbazole pyridinium conjugates exhibited 50 nm red-shifted absorption maxima. Similarly, the carbazole pyridinium conjugates displayed 143–147 nm red-shifted emission maxima in solution. In addition, large Stokes shifts (5747–7558 cm[Formula: see text] were observed for the conjugates in solution. The cell penetrable amphiphilic carbazole pyridinium conjugates exhibited cytoplasmic distribution in A549 cells.

Synthesis, Anti-Cancer and Anti-Migratory Evaluation of 3,6-Dibromocarbazole and 5-Bromoindole Derivatives

In this study, a new series of N-alkyl-3,6-dibromocarbazole and N-alkyl-5-bromoindole derivatives have been synthesized and evaluated in vitro as anti-cancer and anti-migration agents. Cytotoxic and anti-migratory effects of these compounds were evaluated in MCF-7 and MDA-MB-231 breast cancer cell lines and an insight on the structure-activity relationship was developed. Preliminary investigations of their anti-cancer activity demonstrated that several compounds have moderate antiproliferative effects on cancer cell lines with GI50 values in the range of 4.7-32.2 µM. Moreover, carbazole derivatives 10, 14, 15, 23, and 24 inhibit migration activity of metastatic cell line MDA-MB-231 in the range of 18-20%. The effect of compounds 10, 14, and 15 in extension of invadopodia and filopodia was evaluated by fluorescence microscopy and results demonstrated a reduction in actin-based cell extensions by compounds 10 and 15.

Design, synthesis, and carbonic anhydrase inhibition activity of benzenesulfonamide-linked novel pyrazoline derivatives

Carbonic anhydrases (CA, EC 4.2.1.1) are Zinc metalloenzymes and are present throughout most living organisms. Among the catalytically active isoforms are the cytosolic CA I and II, and tumor-associated CA IX and CA XII. The carbonic anhydrase (CA) inhibitory activities of newly synthesized pyrazoline-linked benzenesulfonamides 18-33 against human CA (hCA) isoforms I, II, IX, and XII were measured and compared with that of acetazolamide (AAZ), a standard inhibitor. Potent inhibitory activity against hCA I was exerted by compounds 18-25, with inhibition constant (KI) values of 87.8-244.1 nM, which were greater than that of AAZ (KI, 250.0 nM). Compounds 19, 21, 22, 29, 30, and 32 were proven to have inhibitory activities against hCA IX with KI values (5.5-37.0 nM) that were more effective than or nearly equal to that of AAZ (KI, 25.0 nM). Compounds 20-22, and 30 exerted potent inhibitory activities (KIs, 7.1-10.1 nM) against hCA XII, in comparison with AAZ (KI, 5.7 nM).

Hydrazide-integrated carbazoles: synthesis, computational, anticancer and molecular docking studies

Novel carbazolylmethylene isonictinohydrazides have been synthesized as anticancer agents against pancreatic cancer cells.

Current progress on antioxidants incorporating the pyrazole core

The search of new antioxidants, as drugs candidates, is an active field of medicinal chemistry. The synthesis of compounds with antioxidant potential has increased in recent years and a high number of structurally diverse compounds have been published. This review aims to show the current state-of-the-art on the development of antioxidant compounds incorporating the pyrazole pharmacophore. It is a well-timed review driven by the increasing number of papers, on this issue, that have been published since the beginning of the 21st century (from 2000 to 2017). The aim is to look deeper into the structures already published in the literature containing the pyrazole core as the unique pharmacophore or combined with other pharmacophores and see the relationship between the presence of this five-membered nitrogen heterocycle and the behaviour of the compounds as potential antioxidant agents. An attempt was made to whenever possible establish structure-activity relationships that could help the design of new and more potent antioxidant agents containing this important pharmacophore.