Novel spiroindoline derivatives targeting aldose reductase against diabetic complications: Bioactivity, cytotoxicity, and molecular modeling studies.

Despite significant developments in therapeutic strategies, Diabetes Mellitus remains an increasing concern, leading to various complications, e.g., cataracts, neuropathy, retinopathy, nephropathy, and several cardiovascular diseases. The polyol pathway, which involves Aldose reductase (AR) as a critical enzyme, has been focused on by many researchers as a target for intervention. On the other hand, spiroindoline-based compounds possess remarkable biological properties. This guided us to synthesize novel spiroindoline oxadiazolyl-based acetate derivatives and investigate their biological activities. The synthesized molecules' structures were confirmed herein, using IR, NMR (1H and 13C), and Mass spectroscopy. All compounds were potent inhibitors with KI constants spanning from 0.186 ± 0.020 µM to 0.662 ± 0.042 µM versus AR and appeared as better inhibitors than the clinically used drug, Epalrestat (EPR, KI: 0.841 ± 0.051 µM). Besides its remarkable inhibitory profile compared to EPR, compound 6k (KI: 0.186 ± 0.020 µM) was also determined to have an unusual pharmacokinetic profile. The results showed that 6k had less cytotoxic effect on normal mouse fibroblast (L929) cells (IC50 of 569.58 ± 0.80 µM) and reduced the viability of human breast adenocarcinoma (MCF-7) cells (IC50 of 110.87 ± 0.42 µM) more than the reference drug Doxorubicin (IC50s of 98.26 ± 0.45 µM and 158.49 ± 2.73 µM, respectively), thus exhibiting more potent anticancer activity. Moreover, molecular dynamic simulations for 200 ns were conducted to predict the docked complex's stability and reveal significant amino acid residues that 6k interacts with throughout the simulation.

Structural Characterization of TRAF6 N-Terminal for Therapeutic Uses and Computational Studies on New Derivatives.

Tumor necrosis factor receptor-associated factors (TRAFs) are a protein family with a wide variety of roles and binding partners. Among them, TRAF6, a ubiquitin ligase, possesses unique receptor binding specificity and shows diverse functions in immune system regulation, cellular signaling, central nervous system, and tumor formation. TRAF6 consists of an N-terminal Really Interesting New Gene (RING) domain, multiple zinc fingers, and a C-terminal TRAF domain. TRAF6 is an important therapeutic target for various disorders and structural studies of this protein are crucial for the development of next-generation therapeutics. Here, we presented a TRAF6 N-terminal structure determined at the Turkish light source "Turkish DeLight" to be 3.2 Å resolution at cryogenic temperature (PDB ID: 8HZ2). This structure offers insight into the domain organization and zinc-binding, which are critical for protein function. Since the RING domain and the zinc fingers are key targets for TRAF6 therapeutics, structural insights are crucial for future research. Separately, we rationally designed numerous new compounds and performed molecular docking studies using this template (PDB ID:8HZ2). According to the results, 10 new compounds formed key interactions with essential residues and zinc ion in the N-terminal region of TRAF6. Molecular dynamic (MD) simulations were performed for 300 ns to evaluate the stability of three docked complexes (compounds 256, 322, and 489). Compounds 256 and 489 was found to possess favorable bindings with TRAF6. These new compounds also showed moderate to good pharmacokinetic profiles, making them potential future drug candidates as TRAF6 inhibitors.

Synthesis, anti-inflammatory activity, inverse molecular docking, and acid dissociation constants of new naphthoquinone-thiazole hybrids.

Chronic Inflammation is associated with various types of diseases that involves pro-inflammatory cytokines like IL-6 and TNF-α. High costs and serious side effects of available anti-inflammatory/immunomodulatory drugs led us to design new compounds with promising anti-inflammatory activities. Many drugs and biologically important compounds involve naphthoquinone and thiazole moieties in their core structures. Thereby, here we report the synthesis, characterization and anti-inflammatory activities of new naphthoquinone thiazole hybrids by reaction of naphthoquinone acyl thioureas with various α-bromoketone derivatives. The position of NO2 group in one of the phenyl rings of naphthoquinone thiazole hybrids was changed while different substituents were introduced at the para position of the second phenyl ring. All compounds were tested for potential immunomodulatory effect. No inflammatory cytokines were observed in the absence of LPS stimulant. On the other hand, they had promising anti-inflammatory immunomodulatory activities by being able to decrease the production of the pro-inflammatory cytokines (TNF-α and IL-6) in the LPS-stimulated cells. In an effort to find the possible mechanism of action, several enzymes involved in signalling pathways that play critical roles in inflammatory responses were screened in silico. Subsequent to inverse molecular docking approach, PI3K was predicted be the potential target. The docked complexes of the most potent compounds 5g and 5i were subjected to molecular dynamics simulation to assess the binding stability of the igands with the putative target. Acid dissociation constants (pKa) of the products were also determined potentiometrically.

Novel beta-lactam substituted benzenesulfonamides: in vitro enzyme inhibition, cytotoxic activity and in silico interactions.

In this study, a library of twelve beta-lactam-substituted benzenesulfonamides (5a-l) was synthesized using the tail-approach method. The compounds were characterized using IR, 1H NMR, 13C NMR and elemental analysis techniques. These newly synthesized compounds were tested for their ability to inhibit the activity of two carbonic anhydrases (hCA) isoforms, I and II, and acetylcholinesterase (AChE) in vitro. The results showed that the synthesized compounds were potent inhibitors of hCA I, with KIs in the low nanomolar range (66.60-278.40 nM) than the reference drug acetazolamide (AAZ), which had a KI of 439.17 nM. The hCA II was potently inhibited by compounds 5a, 5d-g and 5l, with KIs of 69.56, 39.64, 79.63, 74.76, 78.93 and 74.94 nM, respectively (AAZ, KI of 98.28 nM). Notably, compound 5a selectively inhibited hCA II with a selectivity of > 4-fold over hCA I. In terms of inhibition of AChE, the synthesized compounds had KIs ranging from 30.95 to 154.50 nM, compared to the reference drug tacrine, which had a KI of 159.61 nM. Compounds 5f, 5h and 5l were also evaluated for their ability to inhibit the MCF-7 cancer cell line proliferation and were found to have promising anticancer activity, more potent than 5-fluorouracil and cisplatin. Molecular docking studies suggested that the sulfonamide moiety of these compounds fits snugly into the active sites of hCAs and interacts with the Zn2+ ion. Furthermore, molecular dynamics simulations were performed for 200 ns to assess the stability and dynamics of each enzyme-ligand complex. The acceptability of the compounds based on Lipinski's and Jorgensen's rules was also estimated from the ADME/T results. These results indicate that the synthesized molecules have the potential to be developed into effective and safe inhibitors of hCAs and AChE and could be lead agents.Communicated by Ramaswamy H. Sarma.

Design, Synthesis, and Evaluation of a New Series of Hydrazones as Small-Molecule Akt Inhibitors for NSCLC Therapy.

In an endeavor to identify small molecules for the management of non-small-cell lung carcinoma, 10 new hydrazone derivatives (3a-j) were synthesized. MTT test was conducted to examine their cytotoxic activities against human lung adenocarcinoma (A549) and mouse embryonic fibroblast (L929) cells. Compounds 3a, 3e, 3g, and 3i were determined as selective antitumor agents on A549 cell line. Further studies were conducted to figure out their mode of action. Compounds 3a and 3g markedly induced apoptosis in A549 cells. However, both compounds did not show any significant inhibitory effect on Akt. On the other hand, in vitro experiments suggest that compounds 3e and 3i are potential anti-NSCLC agents acting through Akt inhibition. Furthermore, molecular docking studies revealed a unique binding mode for compound 3i (the strongest Akt inhibitor in this series), which interacts with both hinge region and acidic pocket of Akt2. However, it is understood that compounds 3a and 3g exert their cytotoxic and apoptotic effects on A549 cells via different pathway(s).

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

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

Quinazolinone-based benzenesulfonamides with low toxicity and high affinity as monoamine oxidase-A inhibitors: Synthesis, biological evaluation and induced-fit docking studies.

The research in selective monoamine oxidases (MAO-A and MAO-B) inhibitors has been increased due to their therapeutic value for neurodegenerative diseases. In this study, 4-((2-(aryl)-4-oxoquinazolin-3(4H)-yl)amino)benzenesulfonamides were synthesized and their MAOs inhibition potentials were investigated applying in vitro fluorometric technique. The most potent compounds 7 and 8 against MAO-A had IC50 values of 0.058 ± 0.002 and 0.094 ± 0.003 µM, respectively, while the reference moclobemide had an IC50 value of 6.061 µM. Compounds 7 (>1724 times) and 8 (>1063 times) more selective and reversible inhibitors of MAO-A rather than MAO-B. Toxicity studies of 7 (IC50 = 210.23 µM) and 8 (IC50 = 259.27 µM) showed that compounds can be considered as non-toxic towards SH-SY5Y cell line at their effective concentrations against MAO-A. In silico docking simulations successfully explained the observed activities and also highlighted structural water molecules to play a key role in the ligand-enzyme interactions. Calculated molecular descriptors are also obeying Lipinski's rule of five and brain/blood partition coefficients, a critical parameter in neurodegenerative diseases. These reversible inhibitors can have considerable advantages compared to irreversible inhibitors which may possess serious pharmacological side effects.

Epichlorohydrin and tripolyphosphate-crosslinked chitosan-kaolin composite for Auramine O dye removal from aqueous solutions: Experimental study and DFT calculations.

Chitosan (Ch, a natural polymer) and kaolin (K, a natural mineral) composite (Ch-K) was produced with the help of two crosslinkers, epichlorohydrin and tripolyphosphate, and then moulded into uniform beads in tripolyphosphate solution. The synthesis was proved by the analyses involving FT-IR and SEM-EDX. The beads were then used as the natural adsorbent for removal of the auramine O (AO), a frequently-used industrial dye, in aqueous solutions. Adsorbent performance of the Ch-K composite for AO dye molecules was optimized: 500 mg L-1 at pH 7.5 at 25 °C. The Langmuir model found 0.118 mol kg-1 for the maximum adsorption capacity of the Ch-K and the D-R isotherm model showed that the nature of the adsorption process was physical. Kinetics of the adsorption could be explained by using both IPD (intraparticle diffusion) and PSO (pseudo second order) models. Thermodynamic parameters demonstrated that the behaviour of the adsorption was an endothermic and spontaneous. The activity of the composite adsorbent was recovered (88%) after the five sequential adsorption/desorption cycles. Supported by experimental findings, the results obtained from in silico modeling at M06-2X/6-31+G (d,p) level helped hypothesise a mechanism for the formation of the Ch-K composite, and shed some light onto the adsorption behaviour of AO dye by assuming several favourable intermolecular interactions.

New bis- and tetrakis-1,2,3-triazole derivatives: Synthesis, DNA cleavage, molecular docking, antimicrobial, antioxidant activity and acid dissociation constants.

In this study, a series of bis- and tetrakis-1,2,3-triazole derivatives were synthesized using copper-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry in 73-95% yield. The bis- and tetrakis-1,2,3-triazoles exhibited significant DNA cleavage activity while the tetrakis-1,2,3-triazole analog 6g completely degraded the plasmid DNA. Molecular docking simulations suggest that compound 6g acts as minor groove binder of DNA by binding through several noncovalent interactions with base pairs. All bis- and tetrakis-1,2,3-triazole derivatives were screened for antibacterial activity against E. coli, B. cereus, S. aureus, P. aeruginosa, E. hirae, L. pneumophila subsp. pneumophila strains and antifungal activity against microfungus C. albicans and C. tropicalis strains. Compound 4d exhibited the best antibacterial activity among bis-1,2,3-triazoles against E. coli and E. hirae, while 6c exhibited the best antibacterial activity among tetrakis-1,2,3-triazoles against E. hirae. Furthermore, the best antifungal activity against C. albicans and C. tropicalis was reported for the compound 5, while 6d displayed the best antifungal activity against C. tropicalis and C. albicans. Reasonable iron chelating activities and DPPH radical scavenging abilities were found for some of the compounds. Finally, the acid dissociation constants (pKa) of the bis-1,2,3-triazoles were also determined with the help of HYPERQUAD program using the data obtained from potentiometric titrations. The reported data here concludes that the bis- and tetrakis-1,2,3-triazoles are important cores that should be considered for further development of especially new anticancer agents acting through the DNA cleavage activity.

Novel imidazo[2,1-b]thiazole-based anticancer agents as potential focal adhesion kinase inhibitors: Synthesis, in silico and in vitro evaluation.

The purpose of this study was to synthesize imidazo[2,1-b]thiazole derivatives, characterize them with spectroscopical techniques and investigate for cytotoxic and apoptotic effects on glioma C6 cancer cell line. The in vitro anticancer activities were also investigated against focal adhesion kinase. Most of the compounds, particularly the derivatives carrying 3-oxo-1-tiya-4-azaspiro[4.5]decane moiety, exhibited higher or comparable activities in comparison with the reference drug, cisplatin. Compounds with methyl, propyl, phenyl moieties at the eighth and second position of the spirothiazolidinone ring showed high FAK inhibitory activities. In addition, molecular docking studies shed light on the binding modes of the synthesized compounds. The critical interactions with amino acid residues located in the active site were revealed. The results obtained from both biological assay data and computational results might provide insight into developing new inhibitors against focal adhesion kinase.

Comprehensive study on potent and selective carbonic anhydrase inhibitors: Synthesis, bioactivities and molecular modelling studies of 4-(3-(2-arylidenehydrazine-1-carbonyl)-5-(thiophen-2-yl)-1H-pyrazole-1-yl) benzenesulfonamides.

In this research, rational design, synthesis, carbonic anhydrases (CAs) inhibitory effects, and cytotoxicities of the 4-(3-(2-arylidenehydrazine-1-carbonyl)-5-(thiophen-2-yl)-1H-pyrazole-1-yl)benzenesulfonamides 1-20 were reported. Compound 18 (Ki = 7.0 nM) was approximately 127 times more selective cancer-associated hCA IX inhibitor over hCA I, while compound 17 (Ki = 10.6 nM) was 47 times more selective inhibitor of hCA XI over hCA II compared to the acetazolamide. Compounds 11 (CC50 = 5.2 µM) and 20 (CC50 = 1.6 µM) showed comparative tumor-specificity (TS= > 38.5; >128.2) with doxorubicin (TS > 43.0) towards HSC-2 cancer cell line. Western blot analysis demonstrated that 11 induced slightly apoptosis whereas 20 did not induce detectable apoptosis. A preliminary analysis showed that some correlation of tumor-specificity of 1-20 with the chemical descriptors that reflect hydrophobic volume, dipole moment, lowest hydrophilic energy, and topological structure. Molecular docking simulations were applied to the synthesized ligands to elucidate the predicted binding mode and selectivity profiles towards hCA I, hCA II, and hCA IX.

Bioactive indanes: insight into the bioactivity of indane dimers related to the lead anti-inflammatory molecule PH46A.

OBJECTIVES: PH46A (1) demonstrates significant anti-inflammatory activity in phenotypic models but its mechanism and site of action have been elusive. Current study focused on the bioactivity of PH46 (2) and related novel indane dimers (6-10) to investigate the impact of changes in substitution and stereochemistry at the C-1 and C-2 positions of the PH46 (2) scaffold. METHODS: Cytotoxicity profiles of compounds were established using THP-1 macrophages and SW480 cells. Effects of the compounds were then evaluated at 10 µm using 5-lipoxygenase (LOX) and 15-LOX enzymes, and 5-LOX binding was evaluated in silico against NDGA, nitric oxide (NO) released from LPS-induced SW480 cells and cytokines in THP-1 macrophages (IL-6, IL-1ß, TNF-α and IFN-γ) and in SW480 cells (IL-8). KEY FINDINGS: PH46 (2) and 7 cause reduction in NO, inhibition of 5-LOX with high binding energy and no cytotoxicity effects in THP-1 macrophages and SW480 cell lines (up to 50 µm). The cytokine profiling of the series demonstrated inhibition of IL-6 and TNF-α in THP-1 macrophages together with IL-8 in SW480 cells. CONCLUSIONS: The observed profile of cytokine modulation (IL-6/ TNF-α, IL-8) and inhibition of release of NO and 5-LOX may contribute to the in vivo effects demonstrated by indane dimers and PH46A (1) in murine models of colitis.

Synthesis, biological evaluation and in silico modelling studies of 1,3,5-trisubstituted pyrazoles carrying benzenesulfonamide as potential anticancer agents and selective cancer-associated hCA IX isoenzyme inhibitors.

Inhibition of carbonic anhydrases (CAs, EC 4.2.1.1) has clinical importance for the treatment of several diseases. They participate in crucial regulatory mechanisms for balancing intracellular and extracellular pH of the cells. Among CA isoforms, selective inhibition of hCA IX has been linked to decreasing of cell growth for both primary tumors and metastases. The discovery of novel CA inhibitors as anticancer drug candidates is a current topic in medicinal chemistry. 1,3,5-Trisubstituted pyrazoles carrying benzenesulfonamide were evaluated against physiologically abundant cytosolic hCA I and hCA II and trans-membrane, tumor-associated hCA IX isoforms by a stopped-flow CO2 hydrase method. Their in vitro cytotoxicities were screened against human oral squamous cell carcinoma (OSCC) cell lines (HSC-2) and human mesenchymal normal oral cells (HGF) via 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) test. Compounds 6, 8, 9, 11, and 12 showed low nanomolar hCA II inhibitory potency with Ki < 10 nM, whereas compounds 9 and 12 displayed Ki < 10 nM against hCA IX isoenzyme when compared with reference Acetazolamide (AZA). Compound 9, 4-(3-(hydrazinecarbonyl)-5-(4-nitrophenyl)-1H-pyrazol-1-yl)benzenesulfonamide, can be considered as the most selective hCA IX inhibitor over off-target cytosolic isoenzymes hCA I and hCA II with the lowest Ki value of 2.3 nM and selectivity ratios of 3217 (hCA I/hCA IX) and 3.9 (hCA II/hCA IX). Isoform selectivity profiles were also discussed using in silico modelling. Cytotoxicity results pointed out that compounds 5 (CC50 = 37.7 µM) and 11 (CC50 = 58.1 µM) can be considered as lead cytotoxic compounds since they were more cytotoxic than 5-Fluorouracil (5-FU) and Methotrexate (MTX).