Novel Phenolic Compounds as Potential Dual EGFR and COX-2 Inhibitors: Design, Semisynthesis, in vitro Biological Evaluation and in silico Insights.

INTRODUCTION: Epidermal growth factor receptor (EGFR) inhibition is an imperative therapeutic approach targeting various types of cancer including colorectal, lung, breast, and pancreatic cancer types. Moreover, cyclooxygenase-2 (COX-2) is frequently overexpressed in different types of cancers and has a role in the promotion of malignancy, apoptosis inhibition, and metastasis of tumor cells. Combination therapy has been emerged to improve the therapeutic benefit against cancer and curb intrinsic and acquired resistance. METHODS: Three semi-synthetic series of compounds (C1-4, P1-4, and G1-4) were prepared and evaluated biologically as potential dual epidermal growth factor receptor (EGFR) and COX-2 inhibitors. The main phenolic constituents of Amaranthus spinosus L. (p-coumaric, caffeic and gallic) acids have been isolated and subsequently subjected to diazo coupling with various amines to get novel three chemical scaffolds with potential anticancer activities. RESULTS: Compounds C4 and G4 showed superior inhibitory activity against EGFR (IC50: 0.9 and 0.5 µM, respectively) and displayed good COX-2 inhibition (IC50: 4.35 and 2.47 µM, respectively). Moreover, the final compounds were further evaluated for their cytotoxic activity against human colon cancer (HT-29), pancreatic cancer (PaCa-2), human malignant melanoma (A375), lung cancer (H-460), and pancreatic ductal cancer (Panc-1) cell lines. Interestingly, compounds C4 and G4 exhibited the highest cytotoxic activity with average IC50 values of 1.5 µM and 2.8 µM against H-460 and Panc-1, respectively. The virtual docking study was conducted to gain proper understandings of the plausible-binding modes of target compounds within EGFR and COX-2 binding sites. DISCUSSION: The NMR of prepared compounds showed characteristic peaks that confirmed the structure of the target compounds. The synthesized benzoxazolyl scaffold containing compounds showed inhibitory activities for both COXs and EGFR which are consistent with the virtual docking study.

Design, Synthesis and Biological Evaluation of 5-amino-3-aryl-1-(6'-chloropyridazin-3'-yl)pyrazoles and their Derivatives as Analgesic Agents.

An efficient and environmental benign solvent-free synthesis of 5-amino-3-aryl-1-(6'-chloropyridazin-3'-yl)pyrazoles (4A-E): was accomplished by grinding 3-chloro-6-hydrazinopyridazine (2): and ß-ketonitriles (3A-E): in the presence of p-toulenesulfonic acid as a catalyst. Subsequently, 6'-chloro group in 4A-E: was replaced with cyclic 2° amine derivatives viz. pyrrolidine 5A: , piperidine 5B: and morpholine 5C: to obtain 6A-E: , 7A-E: , 8A-E: respectively. The newly synthesized compounds were characterized by using IR, NMR (1H and 13C), mass spectral studies, elemental analyses. All the synthesized compounds were studied for their docking interaction with target protein 6COX and screened for their in vivo analgesic mode of action against swiss albino mice (animal model) using acetic-acid induced writhing test. Consequently, docking simulations data justifies the potential of synthesized series as an analgesic and very well correlated with in vivo study. Preliminary results revealed that most of the synthesized compounds exhibited moderate to good analgesic activity as compared to reference/standard drug (s) sodium diclofenac and candidates 4D: and 7C: protrude out as a promising lead for further investigation.

N-arylmethylideneaminophthalimide: Design, Synthesis and Evaluation as Analgesic and Anti-inflammatory Agents.

BACKGROUND AND OBJECTIVE: N-aryl derivatives of phthalimide and 4-nitro phthalimide have demonstrated cyclooxygenase inhibitory activity. Also, they possess excellent analgesic and antiinflammatory activity. In this work, a new series of N-arylmethylideneamino derivatives of phthalimide and 4-nitro phthalimide were designed and synthesized. METHODS: The designed compounds were synthesized by condensation of the appropriate aldehyde and N-aminophthalimide in ethanol at room temperature at PH around 3. Their analgesic and antiinflammatory activity were evaluated by acetic acid-induced pain test and carrageenan-induced paw edema test in mice and rats, respectively. RESULTS AND CONCLUSION: The details of the synthesis and chemical characterization of the analogs are described. In vivo screening showed compounds 3a, 3b, 3f and 3h were the most potent analgesic compounds. In addition, compounds 3a, 3c, 3d, 3e and 3j indicated comparable anti-inflammatory activity to indomethacin as a reference drug.

Computer-aided identification of natural lead compounds as cyclooxygenase-2 inhibitors using virtual screening and molecular dynamic simulation.

In order to find more natural lead-compounds as inhibitors for Cyclooxygenase-2, the essential structural features for human cyclooxygenase-2 inhibitors and 3D-Quantitative structure activity relationship (3D-QSAR) model were carried out based on dataset from three confirmatory bioassays using Phase program. Six point pharmacophore (AAHRRR) of COX-2 selective inhibitors was generated from training set of 52 compounds. The 3D-QSAR model was selected as having favourable statistic measures (R2 = 0.93, Q2ext = 0.81) for the training set and test set respectively. This model was developed using the best pharmacophore hypothesis that helped to reveal the essential features responsible for the anti-inflammatory activity. As a result, this pharmacophore hypothesis has aided in the identification of new four natural lead compounds from UNPD database (UNPD100208, UNPD168234, UNPD91145, UNPD57376) that can be used as potential anti-inflammatory agents or as a core structure to develop other more selective molecules. This result was confirmed by molecular docking, which showed that these four natural lead-compounds adopt the same orientation as Rofecoxib in the COX-2 active site. On the other hand, a molecular dynamic simulation (MDS) was applied and repeated on the top ranking complex 5KIR-UNPD100208 and compared with the results of MDS of 5KIR-Rofecoxib. The results from MDS revealed a good stability of the compound UNPD100208 in the active site based on several parameters such as RMSD, RMSF and potential energy, which can nominate it as a natural anti-inflammatory lead-compound candidate.

LASSBio-1586, an N-acylhydrazone derivative, attenuates nociceptive behavior and the inflammatory response in mice.

Pain and inflammation are complex clinical conditions that are present in a wide variety of disorders. Most drugs used to treat pain and inflammation have potential side effects, which makes it necessary to search for new sources of bioactive molecules. In this paper, we describe the ability of LASSBio-1586, an N-acylhydrazone derivative, to attenuate nociceptive behavior and the inflammatory response in mice. Antinociceptive activity was evaluated through acetic acid-induced writhing and formalin-induced nociception tests. In these experimental models, LASSBio-1586 significantly (p<0.05) reduced nociceptive behavior. Several methods of acute and chronic inflammation induced by different chemical (carrageenan, histamine, croton oil, arachidonic acid) and physical (cotton pellet) agents were used to evaluate the anti-inflammatory effect of LASSBio-1586. LASSBio-1586 exhibited potent anti-inflammatory activity in all tests (p<0.05). Study of the mechanism of action demonstrated the possible involvement of the nitrergic, serotonergic and histamine signaling pathways. In addition, a molecular docking study was performed, indicating that LASSBio-1586 is able to block the COX-2 enzyme, reducing arachidonic acid metabolism and consequently decreasing the production of prostaglandins, which are important inflammatory mediators. In summary, LASSBio-1586 exhibited relevant antinociceptive and anti-inflammatory potential and acted on several targets, making it a candidate for a new multi-target oral anti-inflammatory drug.

Indole Derivatives as Cyclooxygenase Inhibitors: Synthesis, Biological Evaluation and Docking Studies.

A new series of 2-(5-methoxy-2-methyl-1H-indol-3-yl)-N'-[(E)-(substituted phenyl) methylidene] acetohydrazide derivatives (S1⁻S18) were synthesized and evaluated for their anti-inflammatory activity, analgesic activity, ulcerogenic activity, lipid peroxidation, ulcer index and cyclooxygenase expression activities. All the synthesized compounds were in good agreement with spectral and elemental analysis. Three synthesized compounds (S3, S7 and S14) have shown significant anti-inflammatory activity as compared to the reference drug indomethacin. Compound S3 was further tested for ulcerogenic index and cyclooxygenase (COX) expression activity. It was selectively inhibiting COX-2 expression and providing the gastric sparing activity. Docking studies have revealed the potential of these compounds to bind with COX-2 enzyme. Compound S3 formed a hydrogen bond between OH of Tyr 355 and NH2 of Arg 120 with carbonyl group and this hydrogen bond was similar to that formed by indomethacin. This study provides insight for compound S3, as a new lead compound as anti-inflammatory agent and selective COX-2 inhibitor.

Preparation, Characterization and In Vitro / In Vivo Evaluation of Oral Time-Controlled Release Etodolac Pellets.

The objective of this study was to prepare time-controlled release etodolac pellets to facilitate drug administration according to the body's biological rhythm, optimize the drug's desired effects, and minimize adverse effects. The preparation consisted of three laminal layers from center to outside: the core, the swelling layer, and the insoluble polymer membrane. Factors influenced the core and the coating films were investigated in this study. The core pellets formulated with etodolac, lactose, and sodium carboxymethyl starch (CMS-Na) were prepared by extrusion-spheronization and then coated by a fluidized bed coater. Croscarmellose sodium (CC-Na) was selected as the swelling agent, and ethyl cellulose (EC) as the controlled release layer. The prepared pellets were characterized by scanning electron microscopy and evaluated by a dissolution test and a pharmacokinetic study. Compared with commercial available capsules, pharmacokinetics studies in beagle dogs indicated that the prepared pellets release the drug within a short period of time, immediately after a predetermined lag time. A good correlation between in vitro dissolution and in vivo absorption of the pellets was exhibited in the analysis.

Design, Synthesis, and Biological Evaluation of Some Novel Pyrrolizine Derivatives as COX Inhibitors with Anti-Inflammatory/Analgesic Activities and Low Ulcerogenic Liability.

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly prescribed anti-inflammatory and pain relief medications. However, their use is associated with many drawbacks, including mainly serious gastric and renal complications. In an attempt to circumvent these risks, a set of N-(4-bromophenyl)-7-cyano-6-substituted-H-pyrrolizine-5-carboxamide derivatives were designed, synthesized and evaluated as dual COX/5-LOX inhibitors. The structural elucidation, in vivo anti-inflammatory and analgesic activities using a carrageenan-induced rat paw edema model and hot plate assay, were performed, respectively. From the results obtained, it was found that the newly synthesized pyrrolizines exhibited IC50 values in the range of 2.45-5.69 µM and 0.85-3.44 µM for COX-1 and COX-2, respectively. Interestingly, compounds 12, 13, 16 and 17 showed higher anti-inflammatory and analgesic activities compared to ibuprofen. Among these derivatives, compounds 16 and 19 displayed better safety profile than ibuprofen in acute ulcerogenicity and histopathological studies. Furthermore, the docking studies revealed that compound 17 fits nicely into COX-1 and COX-2 binding sites with the highest binding affinity, while compound 16 exerted the highest binding affinity for 5-LOX. In light of these findings, these novel pyrrolizine-5-carboxamide derivatives represent a promising scaffold for further development into potential dual COX/5-LOX inhibitors with safer gastric profile.

Celecoxib analogs bearing benzofuran moiety as cyclooxygenase-2 inhibitors: design, synthesis and evaluation as potential anti-inflammatory agents.

Novel series of celecoxib analogs endowed with benzofuran moiety 3a-e and 9a-d were synthesized and evaluated for COX-1/COX-2 inhibitory activity in vitro. The most potent and selective COX-2 inhibitors - compounds 3c, 3d, 3e, 9c and 9d - were assessed for their anti-inflammatory activity and ulcerogenic liability in vivo. The 3-(pyridin-3-yl)pyrazole derivatives 3c and 3e exhibited the highest anti-inflammatory activity, that is equipotent to celecoxib. Furthermore, the tested compounds proved to have better gastric safety profile compared to celecoxib. In particular, compound 3e demonstrated about 40% reduction in ulcerogenic potential relative to the reference drug. Finally, molecular docking simulation of the new compounds in COX-2 active site and drug likeness studies showed good agreement with the obtained pharmaco-biological results.

Synthesis of new ibuprofen derivatives with their in silico and in vitro cyclooxygenase-2 inhibitions.

Cyclooxygenase-2 (COX-2) is one of the important targets for treatment of inflammation related diseases. In the literature, most of drug candidates are first synthesized and then their COX-2 inhibitory activities are tested by in vitro and in vivo experiments. However, synthesis of dozens of drug analogues without any interpretations on their inhibitory activity can result in loss of time and chemicals. Therefore, synthetic drug designs with molecular modeling are of importance to synthesize selective drug candidates against inflammatory diseases. The synthesis of the novel ibuprofen derivatives through their in silico and in vitro COX-2 inhibitory activities were investigated in the present study. Starting from ibuprofen, ibuprofen amide and ibuprofen acyl hydrazone derivatives were synthesized. According to the results of the in silico molecular docking and in vitro enzyme inhibition studies, the synthesized novel ibuprofen derivatives have selective COX-2 inhibition, and molecule 3a and 3c were showed higher inhibition compared to ibuprofen. In conclusion, the newly synthesized ibuprofen derivatives can be used in model in vivo studies.

Synthesis of three 18F-labelled cyclooxygenase-2 (COX-2) inhibitors based on a pyrimidine scaffold.

Cyclooxygenase (COX) is the key enzyme within the complex conversion of arachidonic acid into prostaglandins (PGs). Inhibitors of this enzyme represent a particularly promising class of compounds for chemoprevention and cancer therapy. The experimental data on the involvement of COX isoform COX-2 in tumour development and progression, as well as the observed overexpression of COX-2 in a variety of human cancers provide the rationale for targeting COX-2 for molecular imaging and therapy of cancer. A series of trifluoromethyl-substituted pyrimidines was prepared as a novel class of selective COX-2 inhibitors, based on the lead structure 1a. All compounds were tested in cyclooxygenase (COX) assays in vitro to determine COX-1 and COX-2 inhibitory potency and selectivity. Molecular docking studies using the catalytic site of COX-1 and COX-2, respectively, provided complementary theoretical support for the obtained experimental biological structure­activity relationship data of three highly potent and selective fluorobenzyl-containing COX-2 inhibitors. Selected fluorobenzyl-substituted pyrimidine derivatives were further developed as (18)F-labelled radiotracers ([(18)F]1a, [(18)F]2a, [(18)F]3a). Radiotracers [(18)F]1a and [(18)F]2a were radiolabelled using 4-[(18)F]fluorobenzylamine ([(18)F]FBA) as a building block. Radiotracer [(18)F]3a was radiofluorinated directly using a nucleophilic aromatic substitution reaction with no-carrier-added (n.c.a.) [(18)F]fluoride on an iodylaryl compound as a labelling precursor.

Synthesis and characterization of celecoxib derivatives as possible anti-inflammatory, analgesic, antioxidant, anticancer and anti-HCV agents.

A series of novel N-(3-substituted aryl/alkyl-4-oxo-1,3-thiazolidin-2-ylidene)-4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamides 2a-e were synthesized by the addition of ethyl a-bromoacetate and anhydrous sodium acetate in dry ethanol to N-(substituted aryl/alkylcarbamothioyl)-4-[5-(4-methylphenyl)-3-(trifluoro-methyl)-1H-pyrazol-1-yl]benzene sulfonamides 1a-e, which were synthesized by the reaction of alkyl/aryl isothiocyanates with celecoxib. The structures of the isolated products were determined by spectral methods and their anti-inflammatory, analgesic, antioxidant, anticancer and anti-HCV NS5B RNA-dependent RNA polymerase (RdRp) activities evaluated. The compounds were also tested for gastric toxicity and selected compound 1a was screened for its anticancer activity against 60 human tumor cell lines. These investigations revealed that compound 1a exhibited anti-inflammatory and analgesic activities and further did not cause tissue damage in liver, kidney, colon and brain compared to untreated controls or celecoxib. Compounds 1c and 1d displayed modest inhibition of HCV NS5B RdRp activity. In conclusion, N-(ethylcarbamothioyl)-4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (1a) may have the potential to be developed into a therapeutic agent.

Design and synthesis of new 1,3-benzdiazinan-4-one derivatives as selective cyclooxygenase (COX-2) inhibitors.

A new group of regioisomeric 2,3-diaryl-1,3-benzdiazinan-4-ones, possessing a methyl sulfonyl pharmacophore, were synthesized and their biological activities were tested for cyclooxygenase-2 (COX-2) inhibitory activity. In vitro COX-1/COX-2 inhibition studies identified 3-(p-fluorophenyl)-2-(4-methylsulfonylphenyl)-1,3-benzdiazinane-4-one (2b) as a potent and highly selective (IC(50) = 0.07 µM; selectivity index = 572.8) COX-2 inhibitor.

Synthesis and evaluation of 1,5-diaryl-substituted tetrazoles as novel selective cyclooxygenase-2 (COX-2) inhibitors.

A series of 1,5-diaryl-substituted tetrazole derivatives was synthesized via conversion of readily available diaryl amides into corresponding imidoylchlorides followed by reaction with sodium azide. All compounds were evaluated by cyclooxygenase (COX) assays in vitro to determine COX-1 and COX-2 inhibitory potency and selectivity. Tetrazoles 3a-e showed IC(50) values ranging from 0.42 to 8.1 mM for COX-1 and 2.0 to 200 µM for COX-2. Most potent compound 3c (IC(50) (COX-2)=2.0 µM) was further used in molecular modeling docking studies.

Semisynthesis and pharmacological investigation of lipo-alkaloids prepared from aconitine.

Processed aconite drugs are widely used in Eastern medicine as painkillers and antirheumatic agents. It is known that the traditional processing of aconite drugs increases the amount of lipo-alkaloids. In order to obtain information about the pharmacological potential of these compounds, semisynthesis of 9 aconitine-derived lipo-alkaloids was carried out and their COX-1, COX-2 and LTB(4) formation inhibitory activities were investigated. It was found that compounds esterified with unsaturated fatty acids demonstrated significant COX-2 inhibitory effects, while in the COX-1 assay only 14-benzoylaconine-8-O-eicosapentaenoate exerted remarkable activity. The inhibition of LTB(4) formation was pronounced in cases of long chain fatty acid derivatives.

Synthesis and evaluation of the anti-inflammatory properties of selenium-derivatives of celecoxib.

Celecoxib is a selective cyclooxygenase (COX)-2 inhibitor used to treat inflammation, while selenium is known to down-regulate the transcription of COX-2 and other pro-inflammatory genes. To expand the anti-inflammatory property, wherein celecoxib could inhibit pro-inflammatory gene expression at extremely low doses, we incorporated selenium (Se) into two Se-derivatives of celecoxib, namely; selenocoxib-2 and selenocoxib-3. In vitro kinetic assays of the inhibition of purified human COX-2 activity by these compounds indicated that celecoxib and selenocoxib-3 had identical K(I) values of 2.3 and 2.4µM; while selenocoxib-2 had a lower K(I) of 0.72µM. Furthermore, selenocoxib-2 inhibited lipopolysaccharide-induced activation of NF-κB leading to the down-regulation of expression of COX-2, iNOS, and TNFα more effectively than selenocoxib-3 and celecoxib in RAW264.7 macrophages and murine bone marrow-derived macrophages. Studies with rat liver microsomes followed by UPLC-MS-MS analysis indicated the formation of selenenylsulfide conjugates of selenocoxib-2 with N-acetylcysteine. Selenocoxib-2 was found to release minor amounts of Se that was effectively inhibited by the CYP inhibitor, sulphaphenazole. While these studies suggest that selenocoxib-2, but not celecoxib and selenocoxib-3, targets upstream events in the NF-κB signaling axis, the ability to effectively suppress NF-κB activation independent of cellular selenoprotein synthesis opens possibilities for a new generation of COX-2 inhibitors with significant and broader anti-inflammatory potential.

Synthesis of some pyrazolyl benzenesulfonamide derivatives as dual anti-inflammatory antimicrobial agents.

Four series of pyrazolylbenzenesulfonamide derivatives were synthesized and evaluated for their anti-inflammatory activity using cotton pellet induced granuloma and carrageenan-induced rat paw edema bioassays. Moreover, COX-1 and COX-2 inhibitory activity, ulcerogenic effect and acute toxicity were also determined. Furthermore, the target compounds were screened for their in-vitro antimicrobial activity against Eischerichia coli, Staphylococcus aureus and Candida albicans. Compounds 4-(3-Phenyl-4-cyano-1H-pyrazol-1-yl)benzenesulfonamide 9a and 4-(3-Tolyl-4-cyano-1H-pyrazol-1-yl)benzenesulfonamide 9b were not only found to be the most active dual anti-inflammatory antimicrobial agents in the present study with good safety margin and minimal ulcerogenic effect but also exhibited good selective inhibitory activity towards COX-2. A docking pose for 9a and 9b separately in the active site of the human COX-2 enzyme was also obtained. Therefore, these compounds would represent a fruitful matrix for the development of dual anti-inflammatory antimicrobial candidates with remarkable COX-2 selectivity.

Synthesis, characterization and preliminary screening of regioisomeric 1-(3-pyridazinyl)-3-arylpyrazole and 1-(3-pyridazinyl)-5-arylpyrazole derivatives towards cyclooxygenase inhibition.

In a search for novel compounds with analgesic and anti-inflammatory activity, a series of regioisomeric 1-(3-pyridazinyl)-3-arylpyrazole (5a-f, 6a-f) and 1-(3-pyridazinyl)-5-arylpyrazole (7a-f, 8a-f) derivatives were synthesized. The structure of these regioisomers was confirmed by spectral techniques. The compounds were preliminarily screened at 8 microM concentration for their inhibitory activity against cyclooxygenase enzymes, COX-1 and COX-2, using a human whole blood test. The tested derivatives showed inhibitory activity for both enzymes and are worthy of further investigation for developing better leads.

Design and study of some novel ibuprofen derivatives with potential nootropic and neuroprotective properties.

Six novel ibuprofen derivatives and related structures, incorporating a proline moiety and designed for neurodegenerative disorders, are studied. They possess anti-inflammatory properties and three of them inhibited lipoxygenase. One compound was found to inhibit cyclooxygenase (COX)-2 production in spleenocytes from arthritic rats. The HS-containing compounds are potent antioxidants and one of them protected against glutathione loss after cerebral ischemia/reperfusion. They demonstrated lipid-lowering ability and seem to acquire low gastrointestinal toxicity. Acetylcholinesterase inhibitory activity, found in two of these compounds, may be an asset to their actions.