Design and synthesis of novel coumarin-benzimidazole hybrids as human galectin-1 inhibitors.

Aim: To develop novel non-carbohydrate inhibitors of human galectin-1 (GAL-1), we have designed a series of coumarin-benzimidazole hybrids. Methods: We synthesized and characterized the coumarin-benzimidazole hybrids and further evaluated them using an in vitro GAL-1 enzyme-linked immunosorbent assay and in silico methods. Results: Among all, the compounds 6p and 6q were found to be potent, with GAL-1 inhibition of 37.61 and 36.92%, respectively, at 10 µM in GAL-1-expressed cell culture supernatant of MCF-7 cells. These two compounds are feasible for fluorine-18 radiolabeling to develop GAL-1 selective PET radiotracers. Computational studies revealed strong binding interactions of GAL-1 with these novel coumarin-benzimidazole hybrids. Conclusion: Coumarin-benzimidazole hybrids can serve as potential leads to develop selective non-carbohydrate GAL-1 inhibitors for cancer therapy.

[Box: see text].

Unraveling the peculiarities and development of novel inhibitors of leishmanial arginyl-tRNA synthetase.

Aminoacylation by tRNA synthetase is a crucial part of protein synthesis and is widely recognized as a therapeutic target for drug development. Unlike the arginyl-tRNA synthetases (ArgRSs) reported previously, here, we report an ArgRS of Leishmania donovani (LdArgRS) that can follow the canonical two-step aminoacylation process. Since a previously uncharacterized insertion region is present within its catalytic domain, we implemented the splicing by overlap extension PCR (SOE-PCR) method to create a deletion mutant (ΔIns-LdArgRS) devoid of this region to investigate its function. Notably, the purified LdArgRS and ΔIns-LdArgRS exhibited different oligomeric states along with variations in their enzymatic activity. The full-length protein showed better catalytic efficiency than ΔIns-LdArgRS, and the insertion region was identified as the tRNA binding domain. In addition, a benzothiazolo-coumarin derivative (Comp-7j) possessing high pharmacokinetic properties was recognized as a competitive and more specific inhibitor of LdArgRS than its human counterpart. Removal of the insertion region altered the mode of inhibition for ΔIns-LdArgRS and caused a reduction in the inhibitor's binding affinity. Both purified proteins depicted variances in the secondary structural content upon ligand binding and thus, thermostability. Apart from the trypanosomatid-specific insertion and Rossmann fold motif, LdArgRS revealed typical structural characteristics of ArgRSs, and Comp-7j was found to bind within the ATP binding pocket. Furthermore, the placement of tRNAArg near the insertion region enhanced the stability and compactness of LdArgRS compared to other ligands. This study thus reports a unique ArgRS with respect to catalytic as well as structural properties, which can be considered a plausible drug target for the derivation of novel anti-leishmanial agents.

Coumarin and Piperazine Conjugates as Selective Inhibitors of the Tumor-associated Carbonic Anhydrase IX and XII Isoforms.

BACKGROUND: Carbonic Anhydrases (CAs) are a family of metalloenzymes that catalyze the reversible interconversion of CO2 and water to bicarbonate and proton. CA isoforms I, II, IX, and XII are considered physiologically and pharmacologically relevant. OBJECTIVE: The objective of this study is to synthesize potent and selective tumor-associated CA IX and XII inhibitors. METHODS: A library of 17 coumarin derivatives clubbed with piperazine and benzyl moiety was designed, synthesized and evaluated for its inhibitory effects and selectivity profile towards physiologically and pharmacologically relevant CA isoforms I, II, IX, and XII. RESULTS: All the derivatives were found to be active against the tumor-associated isoforms IX and XII. The most active compound against hCA (human Carbonic Anhydrase) IX was found to possess a Ki of 229 nM, while the one against hCA XII had a Ki of 294.2 nM. Additionally, two of the compounds were found to have exquisite selectivity towards the off-target hCA I and II isoforms. Moreover, they were found to be approximately 20-fold more selective towards hCA IX than XII. The selectivity of the compounds was further investigated via molecular modeling techniques. CONCLUSION: Coumarin-piperazine hybrids were identified as potent and selective CA IX and XII inhibitors. Molecular modeling techniques provided interesting cues pertaining to observed selectivity.

Automated Radiosynthesis and Molecular Docking Studies of Coumarin- Triazole Hybrid with fluorine-18: A feasibility study.

BACKGROUND: Fluorine-18 is one of the promising radiotracers that can report target specific information related to its physiology to understand the disease status through the PET modality. In the current study, the radiochemical synthesis, purification, and molecular docking studies of fluorine-18 (18F) radiolabeled coumarin-triazole hybrid have been performed. OBJECTIVE: To develop target specific fluorine-18 radiotracer for the diagnosis in oncology. METHODS: GE Tracer-lab FX2N module with few modifications in the line connections was used for the radiosynthesis and purification of target molecule [18F]SG-2, 4-((2,6-dimethylmorpholino) methyl)-7-((1-(4-(fluoro-18F) benzyl)-1H-1,2,3-triazol-4-yl) oxy)-2H-chromen-2-one, through the nucleophilic radiofluorination mechanism. The radiochemical purity was measured by HPLC, and TLC analytical methods. The kryptofix levels were also evaluated by using the TLC method. The residual solvents like DMF, ethanol were measured using GC. The Schrödinger drug discovery suite 2018 was used to study the protein and ligand interactions. RESULTS: The quality control parameters revealed the purity, chemical identity, and limits of residual solvents. The radiochemical purity was 95.5 ± 2.3%, and dimethylformamide solvent limit was 89 ± 3 ppm. The molecular docking results had suggested that the cold target molecule has made strong electronic interactions and showed the possible pharmacokinetic (ADME) properties with galectin-1 protein. Overall, these results showed that [[18F]SG-2 radiolabeling with 18F radionuclide was feasible, and support of molecular docking studies suggest possible interactions with Galectin- 1. CONCLUSION: we reported a feasibility study for labeling coumarin-triazole hybrid with fluorine-18 through aromatic nucleophilic fluorination reaction (SNAr).

Embelin Alleviates Severe Airway Inflammation in OVA-LPS-Induced Rat Model of Allergic Asthma.

BACKGROUND: Asthma is a chronic lung disease, which causes wheezing, tightness in the chest, shortness of breath and coughing. In the wake of coronavirus disease 2019 (COVID-19), which affect the lungs, asthma patients are at high risk. Embelin, a natural benzoquinone obtained mainly from Embelia ribes Burm, has excellent biological properties, including protection against acute asthma. However, since asthma is a chronic and multi-factorial inflammatory disease, asthma conferred by a single allergen in an animal may not be clinically significant. Therefore, the purpose of the current study was to evaluate the effectiveness of embelin against ovalbumin (OVA)-lipopolysaccharide (LPS)-induced severe airway inflammation in experimental animals and to investigate the plausible mechanism of action. METHODS: Rats (n=36) were divided into six groups. Group I served as a normal control. Groups II-VI were sensitised with severe allergens (OVA and LPS) on day 7, 14 and 21, followed by OVA and LPS challenge for 30 min three times/week for 3 weeks. Group II acted as an asthmatic disease control and received only vehicle. On the other hand, groups III-V received embelin (12.5, 25 and 50 mg/kg, P.O. respectively) while group VI received a standard dexamethasone (2.5 mg/kg, P.O.) for 15 days from day 27. Lung function parameters, including the respiratory rate, tidal volume and airflow rate were measured at the end of the experiment (day 42). The total and differential counts of leukocytes in the blood and bronchoalveolar fluid (BALF) were calculated. Th2-mediated serum pro-inflammatory cytokines such as interleukin (IL)-4, IL-5 and IL-13 levels were analyzed. At the end of the study protocol, the lung tissues were removed for a histopathology study. Additionally, a molecular docking simulation on embelin and standard dexamethasone was applied to support the in vivo findings. RESULTS: Significant inhibition of eosinophils, neutrophils, lymphocytes and monocytes in the blood and the BALF was seen in the groups, which received embelin (25 and 50 mg/kg) and dexamethasone (2.5 mg/kg). Moreover, the lung function parameters were normalised by embelin (25 and 50 mg/kg) treatment significantly. The lung histopathological changes confirmed the protective effect of embelin against severe airway inflammation. The docking findings indicated good binding efficacy of embelin to IL-13. CONCLUSION: Overall, our findings indicate that embelin can alleviate severe airway inflammation in OVA-LPS-induced model of allergic asthma occurring by suppression of Th2-mediated immune response. Due to its promising anti-asthmatic effect, it is recommended that embelin should be investigated in clinical trials against asthma. It should also be further explored against COVID-19 or COVID-like diseases due to its ameliorative effects on cytokines and immune cell infiltration.

MEMES: Machine learning framework for Enhanced MolEcular Screening.

In drug discovery applications, high throughput virtual screening exercises are routinely performed to determine an initial set of candidate molecules referred to as "hits". In such an experiment, each molecule from a large small-molecule drug library is evaluated in terms of physical properties such as the docking score against a target receptor. In real-life drug discovery experiments, drug libraries are extremely large but still there is only a minor representation of the essentially infinite chemical space, and evaluation of physical properties for each molecule in the library is not computationally feasible. In the current study, a novel Machine learning framework for Enhanced MolEcular Screening (MEMES) based on Bayesian optimization is proposed for efficient sampling of the chemical space. The proposed framework is demonstrated to identify 90% of the top-1000 molecules from a molecular library of size about 100 million, while calculating the docking score only for about 6% of the complete library. We believe that such a framework would tremendously help to reduce the computational effort in not only drug-discovery but also areas that require such high-throughput experiments.

Non-carbohydrate strategies to inhibit lectin proteins with special emphasis on galectins.

Lectins are a family of glycan-binding proteins, many of which have been established as key targets for therapeutic intervention. They play a central role in many physiological and cellular processes. With the advances in protein crystallography, NMR spectroscopy and computational power over the past couple of decades, the carbohydrate-receptor interactions are now well understood and characterized. Nevertheless, designing efficient carbohydrate inhibitors is a laborious endeavour. They are known to have weak affinities, unsuitable pharmacokinetic properties and highly cumbersome/complex synthetic routes. To circumvent these issues many non-carbohydrate strategies have been reported. Galectins are a sub-family of lectin proteins which have been recognized as crucial targets for a wide variety of diseases. Many candidates targeting galectins are currently in advanced stages of clinical trials. There have been a few reports of non-carbohydrate inhibitors targeting galectins which comprise of peptide-based inhibitors and a recent flourish of heterocyclic inhibitors. In this review, we have briefly highlighted the strategies like fragment-based drug-design and high-throughput screens utilized to identify non-carbohydrate based antagonists for proteins wherein the presence of a sugar was believed to be essential. Additionally, we have described the literature pertaining to non-carbohydrate inhibitors of galectins and how previous reports on rational substitution of a sugar motif could aid in design of heterocyclics that inhibit lectins/galectins. We have concluded with remarks on challenges, gap in our understanding and future perspectives concerned with rational design of non-carbohydrate molecules targeting lectins/galectins.

An updated patent review of galectin-1 and galectin-3 inhibitors and their potential therapeutic applications (2016-present).

INTRODUCTION: Galectins are ubiquitous in nature. They have established themselves as a protein family of high therapeutic potential and play a role in a wide variety of diseases like cancer, fibrosis, and Alzheimer's. Within the galectin family, galectin- 1 and galectin- 3 have been widely studied and their roles and functions have now been well established. AREAS COVERED: In this review, we discuss the important advancements in the development of galectin-1 & 3 inhibitors. All patents filed detailing the divergent strategies to inhibit galectin-1 & 3 from 2016 to present have been covered and discussed. EXPERT OPINION: Over the past couple of decades, distinct galectin inhibitors have been synthesized, reported and studied. Among all, the mono and disaccharide-based antagonists have been found to be considerably successful. However, the cumbersome synthetic route followed to develop this class of inhibitors, in addition to complexity involved in making selective modifications within these molecules has posed a significant challenge. Recently, there have been numerous reports on heterocyclic-based galectin inhibitors. If these are established as potent galectin inhibitors, their ease of synthesis and tunability could overcome the potential drawbacks of carbohydrate-based inhibitors and could thus be exploited to develop efficient and highly specific galectin inhibitors.

Synthesis and biological evaluation of novel 4,7-disubstituted coumarins as selective tumor-associated carbonic anhydrase IX and XII inhibitors.

With an aim to develop novel potential anti-cancer agents we have designed a series of novel 4,7-disubstituted coumarin hybrids synthesis and evaluated for their inhibitory activity against the human carbonic anhydrase isoforms namely CA I, CA II, CA IX and CA XII. The results of CA inhibition clearly showed that the novel 4, 7-disubstituted coumarin hybrids (7a-i & 8a-j) exhibited selective inhibition towards tumor associated isoforms, CA IX and CA XII without inhibiting CA I and CA II isoforms. Among all the compound 8b showed a significant inhibition against hCA IX with a Ki of 0.58 µM whereas, the compound 7c showed a significant inhibition against hCA XII with a Ki of 0.36 µM respectively. All other compounds have shown a good inhibition against hCA IX and hCA XII over hCA I and hCA II within the range of 0.46 to 9.35 µM. Therefore, compound 8b and 7c would be the potential leads for developing selective cytotoxic agents targeting hCA IX and XII.

Synthesis and biological evaluation of some coumarin hybrids as selective carbonic anhydrase IX and XII inhibitors.

Two series, coumarin-linked to thiazolidinone via a pyrazole linker (6a-m, Series 1) and coumarin-linked 1,2,3-triazoles (5a-j, Series 2) were synthesized and the synthesized compounds were subjected for evaluation against the four physiologically and pharmacologically relevant hCA isoforms, hCA I, II, IX and XII. The results indicated selective inhibition of tumor-associated isoforms hCA IX and XII over the off-target isoforms, hCA I and II. The compounds of series 1 exhibited better hCA IX inhibition compared to hCA XII, with compounds 6i, 6h, 6a and 6k, exhibiting notable Ki values of less than 100 nM. Among all the compounds, compound 6i showed the best inhibition with a Ki value of 61.5 nM. Among the compounds of series 2, compounds 5a, 5b, 5c, 5d, 5f and 5j exhibited notable hCA IX inhibition. Compound 5d showed the best inhibition with a Ki value of 32.7 nM. In the case of hCA XII, compound 5i showed the best inhibition with a Ki value of 84.2 nM. Hence, compound 6i from Series 1 and 5d from Series 2 could be taken as lead compounds for the further development of selective and potent hCA IX inhibitors, whereas the compound 5i from Series 2 can be explored further for the design of selective and potent hCA XII inhibitors.

Novel benzimidazole-triazole hybrids as apoptosis inducing agents in lung cancer: Design, synthesis, 18F-radiolabeling & galectin-1 inhibition studies.

In this study, we have synthesized a new series of benzimidazole-triazole hybrids as galectin-1 (gal-1) mediated apoptosis-inducing agents, and evaluated for their potential anticancer activity against a panel of human cancer cell lines viz. breast cancer (MCF-7 and MDA-MB-231) lung cancer (A-549 and NCI-H460), and human keratinocyte cancer (HaCaT), using MTT assay. The target compound 7c exhibited an excellent growth inhibition against lung cancer (A-549 and NCI-H460) cells with an IC50 value of 0.63 ± 0.21 µM, and 0.99 ± 0.01 µM respectively. The target compound 7c also showed a significant growth inhibition against breast cancer (MCF-7 and MDA-MB-23) with an IC50 value of 1.3 ± 0.18 µM, and 0.94 ± 0.02 µM respectively. In addition, the radiochemical synthesis has been performed using fluorine-18 radionuclide in the GE Tracer-lab FX2N module to prove the target compound 7c as a PET imaging agent. In the final stage, the 18F-7c target compound was successfully purified with 60% ethanol in water. The radiochemical purity was achieved >95% using HPLC, and the residual solvent DMF limit was around 78 ± 3 ppm confirmed by GC analysis. Further, the apoptosis induction by 7c in lung cancer (A-549) cells was confirmed as a result of the decrease in MMP levels, increased percentage of apoptotic cells, and sub G1 phase arrest by JC-1 staining, DAPI staining, annexin V-FITC/PI, and flow cytometric analysis. In addition, the target compound 7c significantly reduced the gal-1 protein levels in a dose-dependent manner as confirmed by ELISA studies. The protein binding studies like Surface Plasmon Resonance (SPR) and Fluorescence Spectroscopy (FS) studies indicated that the target compound 7c is capable of binding to gal-1 with an equilibrium constant (KD) value of 1.19E-06 M, and binding constant (Ka) of 9.5 × 103 M-1 respectively. The in-silico computational studies also revealed possible interactions and pharmacokinetic properties (ADMET) of compound 7c with the binding domain of gal-1. Therefore, the novel benzimidazole-triazole hybrids as apoptosis-inducing agents in lung cancer would be potential cytotoxic and PET imaging agents via gal-1.

Design and synthesis of ß-carboline linked aryl sulfonyl piperazine derivatives: DNA topoisomerase II inhibition with DNA binding and apoptosis inducing ability.

A series of new ß-carboline linked aryl sulfonyl piperazine congeners have been synthesized by coupling various ß-carboline acids with substituted aryl sulfonyl piperazines. Evaluation of their anticancer activity against a panel of human cancer cell lines such as colon (HT-29), breast (MDA-MB-231), bone osteosarcoma (MG-63), brain (U87 MG), prostate (PC- 3) and normal monkey kidney (Vero) cell line has been done. Among the series, compound 8ec and 8ed has shown most potent cytotoxicity with an IC50 values of 2.80 ± 0.10 µM and 0.59 ± 0.28 µM respectively against MG-63 cell line and also potent on other cell lines tested. Compounds 8ec and 8ed was found to inhibit Topo II that is confirmed by specific Topo II inhibition assay. DNA binding studies, cell cycle analysis, Annexin V study indicate that these compounds has potential anticancer activity. Molecular docking studies for compound 8ec and 8ed are incorporated to understand the nature of interaction with topoisomerase IIα and dsDNA.

Synthesis and Biological Evaluation of Imidazo[2 ,1-b]Thiazole based Sulfonyl Piperazines as Novel Carbonic Anhydrase II Inhibitors.

A novel series of imidazo[2,1-b]thiazole-sulfonyl piperazine conjugates (9aa-ee) has been synthesized and evaluated for carbonic anhydrase (CA, EC 4.2.1.1) inhibitory potency against four isoforms: The cytosolic isozyme hCA I, II and trans-membrane tumor-associated isoform hCA IX and hCA XII, taking acetazolamide (AAZ) as standard drug, using a stopped flow CO2 hydrase assay. The results revealed that most of the compounds showed selective activity against hCA II whereas none of them were active against hCA I, IX, XII (Ki > 100 µM). The physiologically dominant cytosolic isoform hCA II was inhibited by these molecules with inhibition constants in the range of 57.7-98.2 µM. This new derivative, thus, selectively inhibits hCA II over the hCA I, IX, XII isoforms, which may be used for further understanding the physiological roles of some of these isoforms in various pathologies.

Synthesis, 18F-radiolabeling and apoptosis inducing studies of novel 4, 7-disubstituted coumarins.

In present study, a new series of 4, 7-disubstituted coumarin derivatives (7a-y) have been synthesized as galectin-1 targeting apoptosis inducing agents and evaluated for their in vitro cytotoxic potentials against a panel of selected human cancer cell lines namely, Brest (MCF7), Ovarian (SKOV3), Prostate (PC-3 & DU145) and normal embryonic kidney (HEK293T) cells, using MTT assay. Most of the compounds exhibited potent growth inhibitory action against the treated cancer cell lines with an IC50 range of 10-30 µM. Compound 7q exhibited a significant growth inhibition against prostate cancer (PC-3 & DU145) cell lines with an IC50 value of 7.45 ± 0.03 µM, 8.95 ± 0.17 µM respectively. Further, the target compound 7q was radiolabeled with fluorine-18 [18F] to be used as a novel PET radiotracer for imaging of tumors via targeting galectin-1, using appropriate reaction conditions in the GE Tracer-lab FX2N synthesis module. The purification of the [18F] radiolabeled compound [18F]-7q was successfully achieved with 60% ethanol. The radiochemical purity was>85% and residual solvent limits of DMF was 65 ± 3 ppm as analysed by HPLC, TLC & GC analytical methods. The apoptosis studies confirm the inhibition of cell proliferation with morphological changes like cell shrinkage, blebbing and cell wall deformation, increasing the ROS levels, and loss of mitochondrial membrane potential by Acridine orange/Ethidium bromide staining, Hoechst-33342 staining, H2DCFDA staining, annexin V-FITC/PI, and JC-1 staining methods. In flow cytometric analysis, 7q selectively arrested the sub-G1 phase of the cell cycle in a dose-dependent manner. In Gal-1 ELISA studies, compound 7q efficiently reduced the levels of Gal-1 protein in dose-dependent manner with an IC50 value of 100 µM. The binding constant (Ka) of 7q with Gal-1 was observed as 1.3 × 104 M-1 by fluorescence spectroscopy. The molecular docking studies clearly showed possible interactions and the pharmacokinetic (ADMET) properties of compound 7q with Gal-1. Hence, the novel 4, 7-disubstituted coumarins could be a potential cytotoxic and PET imaging agents via Gal-1.

Design and synthesis of substituted (1-(benzyl)-1H-1,2,3-triazol-4-yl)(piperazin-1-yl)methanone conjugates: study on their apoptosis inducing ability and tubulin polymerization inhibition.

A library of substituted (1-(benzyl)-1H-1,2,3-triazol-4-yl)(piperazin-1-yl)methanone derivatives were designed, synthesized and screened for their in vitro cytotoxic activity against BT-474, HeLa, MCF-7, NCI-H460 and HaCaT cells by employing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Among all the synthesized analogues, compound 10ec displayed the highest cytotoxicity with the IC50 value of 0.99 ± 0.01 µM towards BT-474 cancer cell line. The target compound (10ec) was also evaluated for its tubulin polymerization inhibition study. Detailed biological studies such as acridine orange/ethidium bromide (AO/EB), DAPI and annexin V-FITC/propidium iodide staining assay suggested that compound 10ec induced the apoptosis of BT-474 cells. The clonogenic assay revealed that the inhibition of colony formation in BT-474 cells by 10ec in concentration-dependent manner. Moreover, the flow cytometric analysis revealed that 10ec induced apoptosis via cell cycle arrest at the sub-G1 and G2/M phase. In silico studies of sulfonyl piperazine-integrated triazole conjugates unveil that they possess drug-like properties. According to the molecular modelling studies, compound 10ec binds to the colchicine binding site of the tubulin.

Understanding the role of galectin inhibitors as potential candidates for SARS-CoV-2 spike protein: in silico studies.

The Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) has been rapidly transmitting and leaving its footprints across the globe. Stringent measures like complete lockdown and extensive testing have been employed by many countries to slow it down in its tracks until a viable treatment is found. Therefore, in the current scenario, prompt solutions need to be uncovered to tackle the virus. In the present study, 330 galectin inhibitors were tested against SARS-CoV-2 spike (S) protein with the aid of molecular docking and molecular dynamics. Finally, the binding free energy and contributing energies were calculated for 2 top scoring ligands by using MM-GBSA method. Many of the galectin inhibitors displayed high binding score against the S protein. They were found to bind to the site of contact of S protein to ACE2. Thus, they show promise of disrupting the ACE2-S protein binding and prevent the virus from invading the host cell. Among the ligands screened, TD-139, a molecule currently in Phase IIb clinical trials, was found to be a potential hit. The present study paves the way for in vitro and in vivo testing of galectin inhibitors against SARS-CoV-2. In addition, it warrants a swift examination of TD-139 for treating COVID-19.

Synthesis and exploration of 2-morpholino-4-phenylthiazol-5-yl acrylamide derivatives for their effects against carbonic anhydrase I, II, IX and XII isoforms as a non-sulfonamide class of inhibitors.

Novel series of 2-morpholino-4-phenylthiazol-5-yl acrylamide derivatives (8a-s) have been synthesized and explored as a non-sulfonamide class of carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. The newly synthesized molecules were evaluated for their CA inhibitory potency against four isoforms: the cytosolic isozyme hCA I, II as well as trans-membrane tumor associated isoform hCA IX and hCA XII taking acetazolamide (AAZ) as standard drug. The results revealed that most of the compounds showed good activity against hCA II, IX, and XII whereas none of them were active against hCA I (Ki >100 µM). It is observed that the physiologically most important cytosolic isoform hCA II was inhibited by these molecules in the range of Ki 9.3-77.7 µM. It is also found the both the transmembrane isoforms hCA IX and XII were also inhibited with Kis ranging between 54.7-96.7 µM and 4.6-8.8 µM, respectively. The binding modes of the active compounds within the catalytic pockets of hCA II, IX and XII were evaluated by docking studies. This new non-sulfonamide class of selective inhibitors of hCA II, IX and XII over the hCA I isoform may be used for further understanding the physiological roles of some of these isoforms in various pathologies.

Synthesis of Substituted Cinnamido Linked Quinazolinone Congeners as Potential Anticancer Agents via Mitochondrial Dependent Intrinsic Apoptotic Pathway.

BACKGROUND: The synthesis of novel heterocyclic scaffolds with amide functionality is a key research area due to their plethora of medicinal applications. The present study aims to explore the synthesis of new cinnamido linked quinazolinone congeners and their potential as anticancer agents. METHODS: Cytotoxicity evaluation, Cell cycle analysis, JC-1 staining, ROS, Annexin V assays, AO/EB, DAPI nuclear staining, Colony-forming assay and Western blot analysis. RESULTS: Among the synthesized compounds, 5eb and 5fc have shown promising cytotoxic activity with an IC50 value of 3.89±1.01µM and 4.05±0.62µM against HeLa cell lines. The flow-cytometry analysis demonstrated that the compound 5eb arrested the sub-G1 phase of the cell cycle and induced apoptosis. Furthermore, the compound 5eb triggered the collapse of mitochondrial membrane potential (ΔΨm), which was assessed by JC-1 staining and also induced the generation of Reactive Oxygen Species. An increase in the expression of proapoptotic proteins such as Bax, p53, cleaved PARP and cleaved caspase-3 by 5eb confirmed the activation of the mitochondrial-dependent intrinsic apoptosis pathway. CONCLUSION: Our results suggest that compound 5eb and 5fc of cinnamido linked quinazolinone derivatives could serve as potential leads in the development of novel chemotherapeutic agents.

A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C-C bond cleavage.

An efficient, simple, and metal-free synthetic approach for the N- and O-benzoylation of various amines/benzyl alcohols with pyridinium salts of phenacyl bromides is demonstrated to generate the corresponding amides and esters. This protocol facilitates the oxidative cleavage of a C-C bond followed by formation of a new C-N/C-O bond in the presence of K2CO3. Various pyridinium salts of phenacyl bromides can be readily transformed into a variety of amides and esters which is an alternative method for the conventional amidation and esterification in organic synthesis. High functional group tolerance, broad substrate scope and operational simplicity are the prominent advantages of the current protocol.

Synthesis and biological evaluation of morpholines linked coumarin-triazole hybrids as anticancer agents.

A series of novel morpholines linked coumarin-triazole hybrids (6a-6v) has been synthesized and evaluated for their anti-proliferative potential on a panel of five human cancer cell lines, namely bone (MG-63), lung (A549), breast (MDA-MB-231), colon (HCT-15) and liver (HepG2), using MTT assay. Among all, the compound 6n {7-((1-(2,4-dichlorobenzyl)-1H-1,2,3-triazol-4-yl) methoxy)-4-((2,6-dimethylmorpholino) methyl)-2H-chromen-2-one} showed significant growth inhibition against MG-63 cells with an IC50 value of 0.80 ± 0.22 µM. Further, induction of apoptosis by 6n of MG-63 cells confirmed as a result of morphological changes, the sub-G1 phase arrest, increased percentage of apoptotic cells, and decrease in mitochondrial membrane potential and increase in reactive oxygen species levels. The in vitro Gal-1 expression in cell culture supernatant of MG-63 cells treated with compound 6n showed dose-dependent reduction. The binding constant (Ka ) of 6n with Gal-1 was calculated from the intercept value which was observed as 3.0 × 105  M-1 by fluorescence spectroscopy. Surface plasmon resonance showed that 6n binds to Gal-1 with binding constant (Ka ) of 1.29E+04 1/Ms and equilibrium constant KD value of 7.54E-07 M, respectively. Molecular docking studies revealed the binding interactions of 6n with Gal-1.