Pyrazole–chalcone derivatives as selective COX-2 inhibitors: design, virtual screening, and in vitro analysis

Design, synthesis and molecular modeling of novel D-ring substituted steroidal 4,5-dihydropyrazole thiazolinone derivatives as anti-inflammatory agents by inhibition of COX-2/iNOS production and down-regulation of NF-κB/MAPKs in LPS-induced RAW264.7 macrophage cells

It has been reported that 4,5-dihydropyrazole and thiazole derivatives have many biological functions, especially in the aspect of anti-inflammation. According to the strategy of pharmacophore combination, we introduced thiazolinone and dihydropyrazole moiety into steroid skeleton to design and synthesize a novel series of D-ring substituted steroidal 4,5-dihydropyrazole thiazolinone derivatives, and assessed their in vitro anti-inflammatory profiles against Lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophage cells. The anti-inflammatory activities assay demonstrated that compound 12e was considered as the most effective anti-inflammatory drug, which suppressed the expression of pro-inflammatory mediators including nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), it also dose-dependently inhibited the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-induced RAW 264.7 macrophage cells. Furthermore, the results of the Western blot analysis showed a correlation between the inhibition of the Nuclear factor-kappa B (NF-κB) and Mitogen-activated protein kinases (MAPKs) signaling pathways and the suppressive effects of compound 12e on pro-inflammatory cytokines. Molecular docking studies of compound 12e into the COX-2 protein receptor (PDB ID: 5IKQ) active site was performed to rationalize their COX-2 inhibitory potency. The results were found to be in line with the biological findings as they exerted more favorable interactions compared to that of dexamethasone (DXM), explaining their remarkable COX-2 inhibitory activity. The findings revealed that these candidates could be identified as potent anti-inflammatory agents, compound 12e could be a promising drug for the treatment of inflammatory diseases.

Identification of (4-chlorophenyl)(5-hydroxynaphtho[1,2-b]furan-3-yl)methanone as novel COX-2 inhibitor with analgesic profile

Chronic pain is a serious problem that affects billions of people worldwide, but current analgesic drugs limit their use in chronic pain management due to their respective side effects. As a first-line clinical drug for chronic pain, COX-2 selective inhibitors can relieve mild to moderate pain, but they also have some problems. The most prominent one is that their analgesic intensity is not enough, and they cannot well meet the treatment needs of chronic pain. Therefore, there is an urgent need to develop COX-2 inhibitors with stronger analgesic intensity. In this article, we used virtual screening method to screen out the structurally novel COX-2 inhibitor for chronic pain management, and conducted a preliminary study on its mechanism of action using molecular dynamics simulation.

Targeting AKT2 in MDA-MB-231 Cells by Pyrazole Hybrids: Structural, Biological and Molecular Docking Studies

Pyrazolic hybrids appended with naphthalene, p-chlorobenzene, o-phenol and toluene have been synthesized using Claisen Schmidt condensation reaction of 1-benzyl-3,5-dimethyl-1H-pyrazole-4-carbaldehyde. All compounds were characterized by various spectroscopic techniques. Compound (E)-3-(1-benzyl-3,5-dimethyl-1H-pyrazol-4-yl)-1-(4-chlorophenyl)prop-2-en-1-one crystallizes in monoclinic crystal system with C2/c space group. These synthesized compounds were tested for cytotoxic activity and among these compounds 4b and 5a shows prominent cytotoxic activity against triple-negative breast cancer (TNBC) cells MDA-MB-231 with IC50 values 47.72 μM and 24.25 μM, respectively. Distinguishing morphological changes were noticed in MDA-MB-231 cells treated with pyrazole hybrids contributing to apoptosis action. To get more insight into cytotoxic activity, in silico molecular docking of these compounds were performed and the results suggested that (E)-3-(1-benzyl-3,5-dimethyl-1H-pyrazol-4-yl)-1-(p-tolyl)prop-2-en-1-one and 1-(1'-benzyl-5-(4-chlorophenyl)-3',5'-dimethyl-3,4-dihydro-1'H,2H-[3,4'-bipyrazol]-2-yl)ethan-1-one binds to the prominent domain of Akt2 indicating their potential ability as Akt2 inhibitor. Moreover, from in silico ADME studies clearly demonstrated that these compounds may be regarded as a drug candidate for sub-lingual absorption based on log p values (2.157-4.924). These compounds also show promising antitubercular activity. The overall results suggest that pyrazolic hybrids with substitution at less sterically hindered positions have appealing potent cytotoxic activity and antituberculosis activity due to which they may act as multidrug candidate.

Design, synthesis, and biological evaluation of new 2-(4-(methylsulfonyl)phenyl)-N-phenylimidazo[1,2-a]pyridin-3-amine as selective COX-2 inhibitors

Cyclooxygenase (COX), which plays a role in converting arachidonic acid to inflammatory mediators, could be inhibited by non-steroidal anti-inflammatory drugs (NSAIDs). Although potent NSAIDs are available for the treatment of pain, fever, and inflammation, some side effects, such as gastrointestinal ulcers, limit the use of these medications. In recent years, selective COX-2 inhibitors with a lower incidence of adverse effects attained an important position in medicinal chemistry. In order to introduce some new potent COX-2 inhibitors, a new series of 2-(4-(methylsulfonyl)phenyl)-N-phenylimidazo[1,2-a]pyridin-3-amines was designed, synthesized, and evaluated. The docking studies performed by AutoDock Vina demonstrated that docked molecules were positioned as well as a crystallographic ligand in the COX-2 active site, and SO₂Me pharmacophore was inserted into the secondary pocket of COX-2 and formed hydrogen bonds with the active site. The designed compounds were synthesized through two-step reactions. In the first step, different 1-(4-(methylsulfonyl)phenyl)-2-(phenylamino)ethan-1-one derivatives were obtained by the reaction of aniline derivatives and α-bromo-4-(methylsulfonyl)acetophenone. Then, condensation of intermediates with different 2-aminopyridines gave final compounds. Enzyme inhibition assay and formalin test were performed to evaluate the activity of these compounds. Among these compounds, 8-methyl-2-(4-(methylsulfonyl)phenyl)-N-(p-tolyl)imidazo[1,2-a]pyridin-3-amine (5n) exhibited the highest potency (IC₅₀ = 0.07 µM) and selectivity (selectivity index = 508.6) against COX-2 enzyme (selectivity index: COX-1 IC₅₀/COX-2 IC₅₀). The antinociceptive activity assessment via the formalin test showed that nine derivatives (5a, 5d, 5h, 5i, 5k, 5q, 5r, 5s, and 5t) possessed significant activity compared with the control group with a p value less than 0.05.

Natural-Derived COX-2 Inhibitors as Anticancer Drugs: A Review of their Structural Diversity and Mechanism of Action

Cyclooxygenase-2 (COX-2) is a key-type enzyme playing a crucial role in cancer development, making it a target of high interest for drug designers. In the last two decades, numerous selective COX-2 inhibitors have been approved for various clinical conditions. However, data from clinical trials propose that the prolonged use of COX-2 inhibitors is associated with life-threatening cardiovascular side effects. The data indicate that a slight structural modification can help develop COX-2 selective inhibitors with comparative efficacy and limited side effects. In this regard, secondary metabolites from natural sources offer great hope for developing novel COX-2 inhibitors with potential anticancer activity. In recent years, various nature-derived organic scaffolds are being explored as leads for developing new COX-2 inhibitors. The current review attempts to highlight the COX-2 inhibition activity of some naturally occurring secondary metabolites, concerning their capacity to inhibit COX-1 and COX-2 enzymes and inhibit cancer development, aiming to establish a structure-activity relationship.

Synthesis and Characterization of Novel Heterocyclic Chalcones from 1-Phenyl-1H-pyrazol-3-ol

An efficient synthetic route to construct diverse pyrazole-based chalcones from 1-phenyl-1H-pyrazol-3-ols bearing a formyl or acetyl group on the C4 position of pyrazole ring, employing a base-catalysed Claisen-Schmidt condensation reaction, is described. Isomeric chalcones were further reacted with N-hydroxy-4-toluenesulfonamide and regioselective formation of 3,5-disubstituted 1,2-oxazoles was established. The novel pyrazole-chalcones and 1,2-oxazoles were characterized by an in-depth analysis of NMR spectral data, which were obtained through a combination of standard and advanced NMR spectroscopy techniques.

Design, synthesis, biological evaluation, and docking studies of some novel chalcones as selective COX-2 inhibitors

A new series of chalcones (1-9) possessing an SO₂ CH₃ COX-2 pharmacophore at the para position of the C-1 phenyl ring was synthesized via the Claisen-Schmidt condensation reaction and examined for their inhibition potential against cyclooxygenase (COX) enzymes. Their structures were elucidated by infrared, ¹ H NMR (nuclear magnetic resonance), ¹³ C NMR, and high-resolution mass spectroscopic methods. Enzyme inhibition studies revealed that most of the compounds showed a moderate-to-strong inhibitory activity (IC₅₀  = 0.18-0.34 μM) against the COX-2 enzyme as compared with celecoxib (IC₅₀  = 0.12 μM), ibuprofen (IC₅₀  = 5.33 μM), and nimesulide (IC₅₀  = 1.68 μM). Among these compounds, 1-[4-(methylsulfonyl)phenyl]-3-(2,3-dichlorophenyl)prop-2-en-1-one (5), 1-[4-(methylsulfonyl)phenyl]-3-(2,4-dichlorophenyl)prop-2-en-1-one (6), and 1-[4-(methylsulfonyl)phenyl]-3-(2-chloro-6-fluorophenyl)prop-2-en-1-one (8) became prominent with IC₅₀ values of 0.21, 0.19, and 0.18 μM, respectively. According to molecular docking studies of the most effective compounds, it was found that the compounds interact with amino acids that are important in COX-2 selectivity, such as Arg499 and Phe504.

Novel tetrazole-based selective COX-2 inhibitors: Design, synthesis, anti-inflammatory activity, evaluation of PGE2, TNF-α, IL-6 and histopathological study

To search for effective and selective COX-2 inhibitors, four novel series of tetrazole derivatives were designed based on bioisosteric replacement of SO₂NH₂ in celecoxib with tetrazole ring incorporating different central moieties as chalcone (2a-f), isoxazole (3a-c) or pyrazole (4a-c & 5a-c). Target tetrazoles were synthesized and their structures were confirmed by spectroscopic techniques and elemental analyses. All target compounds were more selective for COX-2 isozyme than COX-1 when compared to standard drugs indomethacin and celecoxib. Compounds 3b, 3c, 4b, 4c, 5b and 5c exhibited potent in vitro COX-2 inhibitory activity (IC₅₀ = 0.039-0.065 μM). Trimethoxy derivatives 3c, 4c and 5c acquired superior COX-2 selectivity index values (SI = 297.67-317.95) and were 1.1 fold higher than celecoxib (SI = 282.22). The most active six compounds were evaluated for their in vivo anti-inflammatory activity and serum levels of PGE₂, TNF-α and IL-6 in addition to their ulcerogenic liability and histopathological profile. At a dose of 50 mg/Kg, compounds 3c and 5c showed better anti-inflammatory activity (% edema inhibition = 29.209-42.643) than celecoxib (% edema inhibition = 28.694-40.114) at different time intervals and were less ulcerogenic (UI = 0.123 and 0.11 in sequent) than celecoxib (UI = 0.167). Also, they displayed potent inhibitory effect on the production of PGE₂ (% inhibition = 81.042 and 82.724 in sequent) greater than celecoxib (% inhibition = 79.666). Compound 5c decreased rat serum concentrations of both TNF-α (% inhibition = 55.349) and IL-6 (% inhibition = 61.561) in a comparable or better activity to celecoxib as reference drug. Finally, docking poses of the most active compounds showed strong binding interactions and effective overall docking energy scores explaining their remarkable COX-2 inhibitory activity.

Synthesis of Hydroxybenzofuranyl-pyrazolyl and Hydroxyphenyl-pyrazolyl Chalcones and Their Corresponding Pyrazoline Derivatives as COX Inhibitors, Anti-inflammatory and Gastroprotective Agents

Five new series of hydroxybenzofuranyl-pyrazolyl chalcones 3a,b, hydroxyphenyl-pyrazolyl chalcones 6a-c and their corresponding pyrazolylpyrazolines 4a, d, 7a-c and 8a-f have been synthesized and evaluated for their in vitro cyclooxygenase (COX)-1 and COX-2 inhibitory activity. All the synthesized compounds exhibited dual COX-1 and COX-2 inhibitory activity with obvious selectivity against COX-2. The pyrazolylpyrazolines 4a-d and 8a-f bearing two vicinal aryl moieties in the pyrazoline nucleus showed more selectivity towards COX-2. Within these two series, derivatives 4c, d and 8d-f bearing the benzenesulfonamide group were the most selective. Compounds 4a-d and 8a-f were further subjected to in vivo anti-inflammatory screening, ulcerogenic liability and showed good anti-inflammatory activity with no ulcerogenic effect. In addition compounds 4c and 8d as examples showed prostaglandin (PG)E2 inhibition % 44.23 and 51.4 respectively, tumor necrosis factor α (TNFα) inhibition % 33.48 and 41.41 respectively and gastroprotective effect in ethanol induced rodent gastric ulcer model. In addition, to explore the binding mode and selectivity of our compounds, 8d and celecoxib were docked into the active site of COX-1 and COX-2. It was found that compound 8d exhibited a binding pattern and interactions similar to that of celecoxib with COX-2 active site, while bitter manner of interaction than celecoxib to COX-1 active site.