Cyclooxygenase-2 Inhibitors. 1,5-Diarylpyrrol-3-acetic Esters with Enhanced Inhibitory Activity toward Cyclooxygenase-2 and Improved Cyclooxygenase-2/Cyclooxygenase-1 Selectivity

BF3-promoted reactions of α-amino acetals with alkynes to 2,5-disubstituted pyrroles

An efficient BF3-promoted cyclization of α-amino acetals with alkynes for the assembly of substituted pyrroles has been developed. This cascade process can be easily achieved through a simple metal-free operation under mild conditions.

A Novel Class of Dual-Acting DCH-CORMs Counteracts Oxidative Stress-Induced Inflammation in Human Primary Tenocytes

Carbon monoxide (CO) can prevent cell and tissue damage by restoring redox homeostasis and counteracting inflammation. CO-releasing molecules (CORMs) can release a controlled amount of CO to cells and are emerging as a safer therapeutic alternative to delivery of CO in vivo. Sustained oxidative stress and inflammation can cause chronic pain and disability in tendon-related diseases, whose therapeutic management is still a challenge. In this light, we developed three small subsets of 1,5-diarylpyrrole and pyrazole dicobalt(0)hexacarbonyl (DCH)-CORMs to assess their potential use in musculoskeletal diseases. A myoglobin-based spectrophotometric assay showed that these CORMs act as slow and efficient CO-releasers. Five selected compounds were then tested on human primary-derived tenocytes before and after hydrogen peroxide stimulation to assess their efficacy in restoring cell redox homeostasis and counteracting inflammation in terms of PGE₂ secretion. The obtained results showed an improvement in tendon homeostasis and a cytoprotective effect, reflecting their activity as CO-releasers, and a reduction of PGE₂ secretion. As these compounds contain structural fragments of COX-2 selective inhibitors, we hypothesized that such a composite mechanism of action results from the combination of CO-release and COX-2 inhibition and that these compounds might have a potential role as dual-acting therapeutic agents in tendon-derived diseases.

Design, synthesis, biological assessment and in silico ADME prediction of new 2-(4-(methylsulfonyl) phenyl) benzimidazoles as selective cyclooxygenase-2 inhibitors

A novel series of benzimidazole derivatives wherein 4-(methylsulfonyl) phenyl pharmacophore attached via its C-2 position was designed and synthesized. These compounds were evaluated in vitro as cyclooxygenase-1(COX-1)/cyclooxygenese-2(COX-2) inhibitors. Furthermore, the synthesized compounds were also in vivo evaluated for their anti-inflammatory activity and ulcerogenic liability. Examination of histopathological lesions was also performed to evaluate the cariogenic effect of most active compounds. In silico prediction of physicochemical properties, ADME, and drug-likeness profiles were also studied. Several compounds as 11b, 11k, 12b, and 12d showed selective inhibition to (COX-2) isozyme. Compound 11b showed the most potent (COX-2) inhibitory activity with (IC₅₀ = 0.10 μM) and selectivity index (SI = 134); the tested compounds also have shown good anti-inflammatory activity. Regarding the ulcerogenic liability, compound 11b was also safest one (Ulcer Index) (UI = 0.83). The results of the molecular docking studies is closely related to the results of the in vitro COX-2 inhibitory activities.

A novel series of benzimidazole derivatives wherein 4-(methylsulfonyl) phenyl pharmacophore attached via its C-2 position was designed and synthesized.

Review on the recent progress in the development of fluorescent probes targeting enzymes

Enzymes are very important for biological processes in a living being, performing similar or multiple tasks in and out of cells, tissues and other organisms at a particular location. The abnormal activity of particular enzyme usually caused serious diseases such as Alzheimer's disease, Parkinson's disease, cancers, diabetes, cardiovascular diseases, arthritis etc. Hence, nondestructive and real-time visualization for certain enzyme is very important for understanding the biological issues, as well as the drug administration and drug metabolism. Fluorescent cellular probe-based enzyme detectionin vitroandin vivohas become broad interest for human disease diagnostics and therapeutics. This review highlights the recent findings and designs of highly sensitive and selective fluorescent cellular probes targeting enzymes for quantitative analysis and bioimaging.

Therapeutic potential for coxibs-nitric oxide releasing hybrids in cystic fibrosis

This review discusses the rational for further studies of COX-2 inhibitors-NO releaser hybrids (NO-Coxibs) in the pharmacological treatment of the airway inflammation in Cystic Fibrosis (CF). Our research group developed several classes of NO-Coxibs for the pharmacological treatment of arthritis, and among them several compounds showed an outstanding in vivo efficacy and good pharmacokinetic properties. The good antiinflammatory properties displayed by these compounds during the previous screening could, by itself, suggest appropriate candidates for further testing in CF.

Identification of new potential cyclooxygenase-2 inhibitors: insight from high throughput virtual screening of 18 million compounds combined with molecular dynamic simulation and quantum mechanics

The cyclooxygenase isoenzymes (COX-1 and COX-2) have a critical role in inflammation, fever, and pain. In contrary to COX-1, COX-2 is specifically expressed in inflamed tissues. Because of the subtle difference between both enzyme active sites, targeting COX-2 represents an efficient strategy for the development of novel inhibitors against inflammation with fewer side effects. In order to identify potential inhibitors of COX-2, more than 18,000,000 small molecules were retrieved from the ZINC database and virtually screened against it with a gradual increase in the precision through combined multistep docking. The results were sorted according to the rank-by-rank, induced-fit docking, and MM-GBSA evaluation. Subsequently from the final hit list, two top hits along with an approved selective inhibitor (celecoxib) were further investigated by the molecular dynamics (MD) simulations. The results were indicated that ZINC16934653 and ZINC40484701 demonstrate the highest affinity for the COX-2 binding pocket. Both ligands were bound to the important active-site residues, which are necessary for the correct orientation of inhibitors inside the binding cavity. Their binding free energies were comparable to celecoxib. 100 ns MD simulation is revealed that ZINC40484701 is more preferred in comparison with ZINC16934653 and celecoxib. In addition, non-covalent interactions between the compounds and key residues located in 6 Å distance from the COX-2 binding site show similar patterns of bonding by the reduced density gradient and the independent gradient model. Therefore, ZINC40484701 can be a potential candidate for further in vitro and in vivo analysis after lead-optimization efforts.Communicated by Ramaswamy H. Sarma.

Medicinal chemistry of vicinal diaryl scaffold: A mini review

The privileged structures have been widely used as a valuable template in new drug discovery. 1,2-Diaryl or vicinal diaryl is a simple scaffold found in many drugs and naturally occurring compounds. From synthetic point of view, the vicinal diaryl derivatives are easily accessible due to their facile and expedient syntheses. These scaffolds have shown numerous interesting pharmacological activities against various diseases with lot of clinical potentials. This review aims to highlight the evidence of vicinal diaryl motif as a privileged scaffold in COX-2 inhibitors and CA-4 analogs.

Synthesis and evaluation of ortho-[18F] fluorocelecoxib for COX-2 cholangiocarcinoma imaging

Background

An ¹⁸F-tagged NSAID analog was prepared for use as a probe for COX-2 expression, which is associated with tumor development.

Methods

The in vivo uptake of celecoxib was monitored with ortho-[¹⁸F]fluorocelecoxib using positron emission tomography (PET). The binding affinity of ortho-[¹⁸F]fluorocelecoxib to COX-1 and COX-2 enzymes were assessed using the competitor celecoxib.

Results

The IC₅₀ values were 0.039 μM and 0.024 μM, respectively. A selectivity index of 1.63 was obtained (COX-2 vs COX-1). COX-2 overexpressed cholangiocarcinoma (CCA) murine cells took up more ortho-[¹⁸F]fluorocelecoxib than that by usual CCA cells from 10 to 60 minutes post incubation. Competitive inhibition (blocking) of the tracer uptake of ortho-[¹⁸F]fluorocelecoxib in the presence of celecoxib by the COX-2 overexpressed CCA cells and the usual CCA cells gave the IC₅₀ values of 0.5 μM and 46.5 μM, respectively. Based on the in vitro accumulation data and in vivo metabolism half-life (30 min), PET scanning was performed 30–60 min after the administration of ortho-[¹⁸F]fluorocelecoxib through the tail vein. Study of ortho-[¹⁸F]F-celecoxib in the CCA rats showed a tumor to normal ratio (T/N) of 1.38±0.23 and uptake dose of 1.14±0.25 (%ID/g).

Conclusion

The inferior in vivo blocking results of 1.48±0.20 (T/N) and 1.18±0.22 (%ID/g) suggests that the nonspecificity is associated with the complex role of peroxidase or the binding to carbonic anhydrase.

Novel 4-methylsulfonylphenyl derivatives as NSAIDS with preferential COX-2 inhibition

Aim: There has been an enormous commercial development following the introduction of selective COX-2 inhibitors. Efforts are continuously done to discover efficient and safe COX-2 inhibitors. Results: A series of 4-methylsulfonylphenyl derivatives was designed, synthesized and screened for preferential inhibition of COX-2 over COX-1 isoforms and in vivo anti-inflammatory activity using the rat paw edema method. The most active ones were investigated via ulcerogenic liability and molecular docking. Physicochemical parameters were calculated for all the newly synthesized compounds. Conclusion: The new compounds showed clear preferential COX-2 over COX-1 inhibition. Selective indices for compounds 4, 6b and 6e were 124, 131 and 119, respectively. Compound 4 reached 71% in vivo anti-inflammatory inhibition. The compounds obeyed ‘Lipinski’s rule of five’.

Coumarin sulfonamides derivatives as potent and selective COX-2 inhibitors with efficacy in suppressing cancer proliferation and metastasis

Cyclooxygenase-2 is frequently overexpression in malignant tumors and the product PGE2 promotes cancer cell progression and metastasis. We designed novel series of coumarin sulfonamides derivatives to improve biological activities of COX-2 inhibition and anticancer. Among them, compound 7t showed most powerful selective inhibitory and antiproliferative activity (IC50=0.09μM for COX-2, IC50=48.20μM for COX-1, IC50=0.36μM against HeLa cells), comparable to the control positive compound Celecoxib (0.31μM, 43.37μM, 7.79μM). Cancer cell apoptosis assay were performed and results indicated that compound 7t effectively fuels HeLa cells apoptosis in a dose and time-dependent manner. Moreover, 7t could significantly suppress cancer cell adhesion, migration and invasion which were essential process of cancer metastasis. Docking simulations results was further indicated that compound 7t could bind well to the COX-2 active site and guided a reasonable design of selective COX-2 inhibitor with anticancer activities in future.

Palladium-Catalyzed Room-Temperature Acylative Suzuki Coupling of High-Order Aryl Borons with Carboxylic Acids

This note describes a dimethyl dicarbonate-assisted, Pd(OAc)2/PPh3-catalyzed acylative Suzuki coupling of carboxylic acids with diarylborinic acids or tetraarylboronates for practical and efficient synthesis of sterically undemanding aryl ketones at room temperature. More than just cost-effective alternatives to aryl boronic acids, diarylborinic acids and tetraarylboronates displayed higher reactivity in the acylative Suzuki coupling. A variety of alkyl aryl ketones, including those bearing a hydroxy, bromo, or carbonyl group, could be readily obtained in modest to excellent yields.

Design, synthesis and evaluation of benzenesulfonamide-substituted 1,5-diarylpyrazoles containing phenylacetohydrazide derivatives as COX-1/COX-2 agents against solid tumors

Novel benzenesulfonamide-substituted 1,5-diarylpyrazoles containing phenylacetohydrazide derivatives have been synthesized. Among them, 48 showed best antiproliferative activity against A549 cells and was evaluated as a selective COX-2 inhibitor.

COX inhibitors: a patent review (2011 - 2014)

INTRODUCTION

The COX enzymes play a central role in the biosynthetic pathway of important biological mediators called prostanoids. Differences in regulation of gene expression, stability of transcripts and proteins determine the different biological functions of COX-1 and COX-2. While the COX-1 gene has been considered to be a 'housekeeping' gene expressed in many tissues and cells, COX-2 gene is upregulated during inflammation, hypoxia and in many cancers.

AREAS COVERED

The first part of this review provides a survey of the development of both modified traditional NSAIDs (tNSAIDs) and COX inhibitors (coxibs) with reduced side effects for the treatment of inflammation and cancer. The second part deals with patents reporting several dual inhibitors characterized by the conjugation of a COX-inhibitor scaffold to a molecule able to modulate a different target. Finally, two patents on novel COX inhibitor scaffolds are reported.

EXPERT OPINION

The most interesting branch of research concerns the conjugation of a COX-inhibitor scaffold to a molecule able to modulate a different target, in order to either enhance anti-inflammatory activity or to act as a dual inhibitor. Among the described compounds, selenium-containing coxibs inhibiting COX-2 and Akt, in addition to the multi-target biphenyl derivatives as dual inhibitors of COX and fatty acid amide hydrolase, are the most promising ones.

Synthesis and evaluation of new benzimidazole-based COX inhibitors: a naproxen-like interaction detected by STD-NMR

Non-steroidal anti-inflammatory drugs exert their pharmacological activity through inhibition of cyclooxygenase 1 and 2 (COX-1 and COX-2).

Hydroxycinnamic acid as a novel scaffold for the development of cyclooxygenase-2 inhibitors

The most active hydroxycinnamic acid derivative, caffeic acid diethyl ester (CA-DE), demonstrated 88.5/30.5% inhibition at 100/20 μM against COX-2 and negligible COX-1 inhibitory effect. CA-DE showed preferred interactions with COX-2 active site.

Development and characterization of 3-(benzylsulfonamido)benzamides as potent and selective SIRT2 inhibitors

Inhibitors of sirtuin-2 deacetylase (SIRT2) have been shown to be protective in various models of Huntington's disease (HD) by decreasing polyglutamine aggregation, a hallmark of HD pathology. The present study was directed at optimizing the potency of SIRT2 inhibitors containing the neuroprotective sulfobenzoic acid scaffold and improving their pharmacology. To achieve that goal, 176 analogues were designed, synthesized, and tested in deacetylation assays against the activities of major human sirtuins SIRT1-3. This screen yielded 15 compounds with enhanced potency for SIRT2 inhibition and 11 compounds having SIRT2 inhibition equal to reference compound AK-1. The newly synthesized compounds also demonstrated higher SIRT2 selectivity over SIRT1 and SIRT3. These candidates were subjected to a dose-response bioactivity assay, measuring an increase in α-tubulin K40 acetylation in two neuronal cell lines, which yielded five compounds bioactive in both cell lines and eight compounds bioactive in at least one of the cell lines tested. These bioactive compounds were subsequently tested in a tertiary polyglutamine aggregation assay, which identified five inhibitors. ADME properties of the bioactive SIRT2 inhibitors were assessed, which revealed a significant improvement of the pharmacological properties of the new entities, reaching closer to the goal of a clinically-viable candidate.

In vitro effects of VA441, a new selective cyclooxygenase-2 inhibitor, on human osteoarthritic chondrocytes exposed to IL-1β

The aim of this in vitro study was to examine the possible effect of [2-methyl-5-(4-methylsulphonyl)phenyl-1-phenyl-3-(2-n-propyloxyethyl)]-1H-pyrrole (VA441), a new selective cyclooxygenase (COX)-2 inhibitor, on human osteoarthritic (OA) chondrocyte cultivated in the presence or absence of interleukin-1β (IL-1β). In particular, we assessed the effects of 1 and 10 μM of VA441, celecoxib, and indomethacin on cell viability, COX-2 and inducible nitric oxide synthase (iNOS) gene expression, prostaglandin E(2) (PGE(2)) production, and nitric oxide (NO) and metalloproteinase-3 (MMP-3) release. Furthermore, we carried out morphological assessment by transmission electron microscopy (TEM). The presence of IL-1β led to a significant increase in PGE(2), MMP-3, and NO production, as well as a significant increase in gene expression of COX-2 and iNOS. All the drugs tested had a statistically significant inhibitory effect on PGE(2) production and gene expression of COX-2 stimulated by IL-1β. VA441 and celecoxib significantly suppressed IL-1β-stimulated MMP-3 and NO and iNOS gene expression in a dose-dependent manner, while indomethacin did not show any significant effect on MMP-3 and NO production or on iNOS gene expression. TEM demonstrated that IL-1β severely alters the structure of chondrocytes; after co-incubation with VA441 or celecoxib, the cells recovered their ultrastructure. Our data suggest that VA441 and celecoxib may have a beneficial effect on chondrocyte metabolism.

Indole based cyclooxygenase inhibitors: synthesis, biological evaluation, docking and NMR screening

The close structural similarity between the two cyclooxygenase (COXs) isoforms and the absence of selective inhibitors without side effects continues to stimulate the development of novel approaches towards selective anti-inflammatory drugs. In the present study a small library of new indolic compounds involving two different substitutions patterns at the indole scaffold was synthesized. In order to establish a relation between the spatial distribution of known functional groups related with inhibitory activity, two substitution patterns were explored: one with substituents at N-1, C-3, C-5 positions and another at C-2, C-3 and C5 positions. Accordingly, indole positions C-5, C-3 and N-1 were substituted with: sulfonamide or methylsulfone at C-5, p-halo-benzyl group at C-3, and an alkyl chain with a trifluoromethyl group at N-1. Alternatively, a p-halo-benzyl group was introduced at C-2, leaving the indolic nitrogen free. Inhibitory studies were performed and the activity results obtained against both COXs isoforms were rationalized based on docking and NMR studies. Docking studies show that dialkyation at C-2 and C-3 favors a binding with an orientation similar to that of the known selective inhibitor SC-558. From the tested compounds, this substitution pattern is correlated with the highest inhibitory activity and selectivity: 70% COX-2 inhibition at 50 μM, and low COX-1 inhibition (18 ± 9%). Additionally, Saturation Transfer Difference NMR experiments reveal different interaction patterns with both COXs isoforms that may be related with different orientations of the sulfonamide group in the binding pocket. Despite the moderated inhibitory activities found, this study represents an innovative approach towards COXs inhibitory activity rationalization and to the design of anti-inflammatory drugs.

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): Progress in Small Molecule Drug Development

Ever since the discovery of aspirin, small molecule therapeutics have been widely prescribed to treat inflammation and pain. Aspirin and several small molecule NSAIDs are known to inhibit the enzymes cyclooxygenase-1 (COX-1) and -2 (COX-2). Despite the success of NSAIDs to treat inflammatory disorders, the development of a clinically useful small molecule NSAIDs with decreased side effect profiles is an ongoing effort. The recent discovery and development of selective COX-2 inhibitors was a step toward this direction. Emerging trends are represented by the progress in the development of hybrid agents such as nitric oxide donor-NSAIDs (NO-NSAIDs) and dual COX/lipoxygenase (LOX) inhibitors. This review focuses on the recent advances in the rational design of small molecule NSAIDs in therapy.

2-Amino-5-sulfanyl-1,3,4-thiadiazoles: a new series of selective cyclooxygenase-2 inhibitors

A new series of cyclooxygenase-2 inhibitors with 2-amino-5-sulfanyl-1,3,4-thiadiazole as the central scaffold unit has been synthesized. The newly synthesized compounds were characterized by analytical and spectral methods. Compounds were screened for cyclooxygenase inhibitory activity by the colorimetric COX (ovine) inhibitor screening assay, anti-inflammatory activity by the carrageenean induced rat paw oedema test and analgesic activity by the tail flick method. Some compounds exhibited significant biological activity.