Synthesis,biological evaluation and docking study of a new series of di-substituted benzoxazole derivatives as selective COX-2 inhibitors and anti-inflammatory agents

A new series of substituted-N-(3,4-dimethoxyphenyl)-benzoxazole derivatives 13a–13p was synthesized and evaluated in vitro for their COX (I and II) inhibitory activity, in vivo anti-inflammatory and ulcerogenic potential. Compounds 13d, 13h, 13k, 13l and 13n exhibited significant COX-2 inhibitory activity and selectivity towards COX-2 over COX-1. These selected compounds were screened for their in vivo anti-inflammatory activity by carrageenan induced rat paw edema method. Among these compounds, 13d was the most promising analogs of the series with percent inhibition of 84.09 and IC₅₀ value of 0.04?µM and 1.02?µM (COX-2 and COX-1) respectively. Furthermore, ulcerogenic study was performed and tested compounds (13d, 13h, 13k, 13l) demonstrated a significant gastric tolerance than ibuprofen. Molecular docking study was also performed with resolved crystal structure of COX-2 to understand the binding mechanisms of newly synthesized inhibitors in the active site of COX-2 enzyme and the results were found to be concordant with the biological evaluation studies of the compounds. These newly synthesized inhibitors also showed acceptable pharmacokinetic profile in the in silico ADME/T analyses.     

Design,synthesis, biological evaluation,and molecular docking of chalcone derivatives as anti-inflammatory agents

In this study, two series of 35 new chalcone derivatives containing aryl-piperazine or aryl-sulfonyl-piperazine fragment were synthesized and their structures were characterized by ¹H, ¹³C and ESI-MS. The in vivo and in vitro anti-inflammatory activities of target compounds were evaluated by using classical para-xylene-induced mice ear-swelling model and ELISA assays. Furthermore, docking studies were performed in COX-2 (4PH9). The in vivo anti-inflammatory assays indicated that most of the target compounds showed significant anti-inflammatory activities. Docking results revealed that the anti-inflammatory activities of compounds correlated with their docking results. Especially, compound 6o exhibited the most potent anti-inflammatory activity in vivo with the lowest docking score of ?17.4 kcal/mol and could significantly inhibit the release of LPS-induced IL-6 and TNF-α in a dose-dependent manner in vitro.     

Synthesis of new pyrazoles and pyrozolo [3,4-b] pyridines as anti-inflammatory agents by inhibition of COX-2 enzyme

New pyrazoles and pyrazolo[3,4-b] pyridines were synthesized and their structure was confirmed by elemental analyses as well as IR, ¹H NMR, ¹³C NMR, and mass spectral data. All the newly synthesized derivatives were evaluated in vitro for inhibitory activity against COX-1 and COX-2 enzymes and their IC₅₀ values were calculated, most of the derivatives showed good inhibitory activity with derivatives IVb, IVh and IVJ showing inhibitory activity better than celecoxib. Moreover, the eight most potent derivatives IVa, IVb, IVc, IVd, IVe, IVh, IVJ, and IVL were selected for in vivo assay to measure their effect on paw edema in rates and their ulcerogenic effect. Compounds IVa, IVb and IVc were found to be the most active and selective as COX-2 inhibitors and most effective in protection from edema, they were also found to have lowest ulcerogenic effect among all derivatives.     

Synthesis, biological evaluation and molecular docking studies of stellatin derivatives as cyclooxygenase (COX-1, COX-2) inhibitors and anti-inflammatory agents

Stellatin (4), isolated from Dysophylla stellata is a cyclooxygenase (COX) inhibitor. The present study reports the synthesis and biological evaluation of new stellatin derivatives for COX-1, COX-2 inhibitory and anti-inflammatory activities. Eight derivatives showed more pronounced COX-2 inhibition than stellatin and, 17 and 21 exhibited the highest COX-2 inhibition. They also exhibited the significant anti-inflammatory activity in TPA-induced mouse ear edema assay and their anti-inflammatory effects were more than that of stellatin and indomethacin at 0.5 mg/ear. The derivatives were further evaluated for antioxidant activity wherein 16 and 17 showed potent free radical scavenging activity against DPPH and ABTS radicals. Molecular docking study revealed the binding orientations of stellatin and its derivatives into the active sites of COX-1 and COX-2 and thereby helps to design the potent inhibitors.     

Synthesis,biological evaluation and molecular modeling study of pyrazole derivatives as selective COX-2 inhibitors and anti-inflammatory agents

A novel series of pyrazole derivatives were synthesized and evaluated in vivo for their anti-inflammatory activity in carrageenan-induced rat paw edema model. Among all compounds, 5a, and 5b showed comparable anti-inflammatory activity to Nimesulide, the standard drug taken for the studies. In silico (docking) studies were carried out to investigate the theoretical binding mode of the compounds to target the cyclooxygenase (COX-2) using Autodock 4.2.     

Design,synthesis of 2,3-disubstitued 4(3H)-quinazolinone derivatives as anti-inflammatory and analgesic agents: COX-1/2 inhibitory activities and molecular docking studies

A new series, 2-substituted mercapto-3-[2-(pyridin-2-yl)ethyl]-4(3H)-quinazolinone 1–21, was synthesized and evaluated for in vivo anti-inflammatory and analgesic activities and in vitro COX-1/COX-2 inhibition. Compounds 1, 4, 5, 6, 8, 10, 13, 14, 15, 16, and 17 exhibited potent anti-inflammatory and analgesic properties, with ED₅₀ values of 50.3–112.1 mg/kg and 12.3–111.3 mg/kg, respectively. These values may be compared with those of diclofenac sodium (ED₅₀ = 112.2 and 100.4 mg/kg) and celecoxib (ED₅₀ = 84.3 and 71.6 mg/kg). Compounds 4 and 6 possessed strong COX-2 inhibitory activity with IC₅₀ (0.33 μM and 0.40 μM, respectively) and selectivity index (SI > 303.0 and >250.0, respectively) values that are similar to those of the reference drug celecoxib (IC₅₀ 0.30 μM and COX-2 SI > 333). Compounds 5, 8, and 13 demonstrated effective COX-2 inhibitory activity with IC₅₀ values of 0.70–0.80 μM and COX-2 SI > 125–142. Potent COX-2 inhibitors, such as compounds 4, 6, and 13, were docked into the active site pockets of COX-1 and COX-2, with the greatest recognition occurring at the COX-2 binding site and insignificant interactions at the binding site of the COX-1 pocket.     

Synthesis,anti-inflammatory,analgesic, COX-1/2 inhibition activities and molecular docking study of pyrazoline derivatives

Design, synthesis and pharmacological activities of a group of 1,3,5-trisubstituted pyrazolines were reported. The chemical structures of the synthesized compounds have been assigned on the basis of IR, MS, ¹H NMR, and ¹³C NMR spectral analyses. The synthesized 1,3,5-trisubstituted pyrazoline derivatives were evaluated in vivo for anti-inflammatory, analgesic activities and in vitro for COX-1/2 inhibition assay. Among the tested compounds, derivatives 4h, 6e, 7a, 7e, and 9 showed more potent anti-inflammatory and analgesic activities than the reference drug celecoxib. On the basis of their higher activities in the in vivo studies compared with celecoxib, the five compounds 4h, 6e, 7a, 7e and 9 were selected to test their inhibitory activities against ovine COX-1/2 using an in vitro cyclooxygenase inhibition assay. Docking study of compounds 7a, 7e and 9 into the COX-2 binding site revealed a similar binding mode to SC-558, a selective COX-2 inhibitor.     

Synthesis,biological evaluation of benzothiazole derivatives bearing a 1,3,4-oxadiazole moiety as potential anti-oxidant and anti-inflammatory agents

Twenty benzothiazole derivatives bearing a 1,3,4-oxadiazole moiety were synthesized and evaluated for their anti-oxidant and anti-inflammatory activities. Among these compounds, 8h and 8l were appeared to have high radical scavenging efficacies as 0.05 ± 0.02 and 0.07 ± 0.03 mmol/L of IC₅₀ values in ABTS⁺ bioassay, respectively. In anti-inflammatory tests, compound 8h displayed good activity with 57.35% inhibition after intraperitoneal administration, which was more potent than the reference drug (indomethacin). Molecular modeling studies were performed to investigate the binding mode of the representative compound 8h into COX-2 enzyme. In vitro enzyme study implied that compound 8h exerted its anti-inflammatory activity through COX-2 inhibition.     

Pyrazoles containing thiophene,thienopyrimidine and thienotriazolopyrimidine as COX-2 selective inhibitors: Design,synthesis, in vivo anti-inflammatory activity,docking and in silico chemo-informatic studies

New thiophene and annulated thiophene pyrazole hybrids were synthesized and screened for their in vitro COX-1/COX-2 enzymatic inhibition and in vivo anti-inflammatory activities. All compounds were more COX-2 selective inhibitors than COX-1 with compound 13 exhibiting the highest COX-2 selectivity index. Compounds 3, 6a, 9 and 11 were the most promising in the acute anti-inflammatory assay while compounds 3, 5, 6a, 6c, 9, 10, 11 and 13 exerted promising anti-inflammatory activity in the sub-acute anti-inflammatory assay. Compounds 3, 6a, 6c, 9, 10 and 11 were evaluated for their ED₅₀ values and were more potent than diclofenac sodium while compounds 6a, 6c and 9 were of greater potency than celecoxib with compound 6a being the most potent showing ED₅₀ = 0.033 mmol/kg. These compounds were non-toxic and proved to be gastrointestinal safe compared to indomethacin, diclofenac sodium and celecoxib. Docking studies into COX-2 active site (PDB code 3LN1) revealed that compounds 3, 6a, 6c, 9, 10, 11 and 13 had binding modes and energies comparable to that of celecoxib. Compounds 3, 9, 10 and 11 complied with Lipinski’s RO5 while compounds 6a and 6c showed one violation whereas compound 13 deviated by 2 violations. Compounds 6a, 6c and 13 showed 100% plasma protein binding (PPB) and showed no aqueous solubility while compounds 3, 10 and 11 demonstrated the best drug likeness model scores. Therefore, the thiophene analog 3 and the thienopyrimidine derivatives 10 and 11 are promising anti-inflammatory candidates that exert moderate selective COX-2 inhibition with acceptable physicochemical properties.     

1,4-Dihydroquinazolin-3(2H)-yl benzamide derivatives as anti-inflammatory and analgesic agents with an improved gastric profile: Design,synthesis, COX-1/2 inhibitory activity and molecular docking study

The design and synthesis of a new series of 1,4-dihydroquinazolin-3(2H)-yl benzamide derivatives (4a–o) as anti-inflammatory and analgesic agents and COX-1/2 inhibitors are reported. The target compounds (4a–o) were synthesized using a two-step scheme, and their chemical structures were confirmed with ¹H NMR, ¹³C NMR, and mass spectra and elemental analysis. Compounds 4b, 4d, 4h, 4l, 4n and 4o showed the best in vitro COX-2 inhibitory activity (IC₅₀ 0.04–0.07 μM), which was nearly the same as that of the reference drug celecoxib (IC₅₀ 0.049 μM), but had a lower selectivity index, as dictated in our target design. In the in vivo anti-inflammatory inhibition assay, compounds 4b, 4c, 4e, 4f, 4m and 4o showed better oedema inhibition percentages, ranging from 38.1% to 54.1%, than did diclofenac sodium (37.8%). An in vivo analgesic assay revealed that compounds 4b and 4n had a potential analgesic effect 4- to 21-fold more potent than that of indomethacin and diclofenac sodium. All the tested compounds showed an improved ulcerogenic index when compared to indomethacin. In the synthesized series, compound 4b showed the best biological activity in all the experiments. The docking study results agreed with the in vitro COX inhibition assay results. Moreover, the predicted in silico studies of all the compounds support their potential as drug candidates.     

Novel 3-substituted-1-aryl-5-phenyl-6-anilinopyrazolo[3,4-d]pyrimidin-4-ones: Docking,synthesis and pharmacological evaluation as a potential anti-inflammatory agents

Novel 3-substituted-1-aryl-5-phenyl-6-anilino-pyrazolo[3,4-d]pyrimidin-4-ones of pharmacological significance were synthesized by the reaction of ethyl-(5-amino-3-methylthio-1-aryl-5-phenyl-2H-pyrazole)-4-carboxylates 3a–c with S-methyl diphenyl thiourea independently to produce 1-aryl-3-thiomethyl-5-phenyl-pyrazolo[3,4-d]pyrimidines 4a–c in DMF with catalytic amount of K₂CO₃, which on further treatment with different aromatic amines independently under same reaction conditions generated for compounds 5a–l. The compounds were screened for the anti-inflammatory activity and evaluated for ulcerogenic potential. The compounds 5i exhibited superior anti-inflammatory activity in comparison with diclofenac sodium and comparable activity with celecoxib at a dose of 25 mg/kg. The other compounds 4c, 5c, 5f and 5l were found as active with inhibition of edema in the range of 35–39 after 3 h of administration of test compounds. The ulcerogenic potential of active compounds was observed to be quite lesser as compared to standard. COX-2 docking score of the active compound 5i was found to be better than standard celecoxib.     

Synthesis and biological evaluation of phenyl-1H-1,2,3-triazole derivatives as anti-inflammatory agents

Rapid and efficient synthesis of a phenyl-1H-1,2,3-triazole library enabled cost-effective biological testing of a range of novel non-steroidal anti-inflammatory drugs with potential for improved drug efficacy and toxicity profiles. Anti-inflammatory activities of the phenyl-1H-1,2,3-triazole analogs synthesized in this report were assessed using the xylene-induced ear edema model in mice. At least four analogs, 2a, 2b, 2c, and 4a, showed more potent effects than the reference anti-inflammatory drug diclofenac at the same dose of 25 mg/kg. To explore relationships between the structural properties of phenyl-1H-1,2,3-triazole analogs and their anti-inflammatory activities in xylene-induced ear edema, comparative molecular field analysis was performed, and pharmacophores showing good anti-inflammatory activities were identified based on an analysis of contour maps obtained from comparative molecular field analysis. The anti-inflammatory effect on the molecular level was tested by the expression of tumor necrosis factor-alpha induced COX-2 using Western blots. Because the addition of the analog 2c caused the expression change of TNF-α induced COX-2, the molecular binding mode between 2c and COX-2 was elucidated using in silico docking.     

Synthesis of phenylpiperazine derivatives of 1,4-benzodioxan as selective COX-2 inhibitors and anti-inflammatory agents

1-((2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)methyl)-4-substituted-phenylpiperazine moiety was prepared and has been found to be a new and selective ligand for the enzyme cyclooxygenase-2 (COX-2). The biological activity of compound 3k as anti-inflammatory agent was further investigated both in vitro and in vivo. Notably, compound 3k exhibited the best anti-inflammatory activity among the eleven designed compounds with no toxicity, as determined by the ulcerogenic activity. Computational docking studies also showed that compound 3k has interaction with COX-2 key residues in the active site. Compound 3k maybe a new anti-inflammatory lead-candidate as powerful and novel non-ulcerogenic.     

Pyrazole-hydrazone derivatives as anti-inflammatory agents: Design,synthesis, biological evaluation,COX-1,2/5-LOX inhibition and docking study

A new series of pyrazole-hydrazone derivatives 4a-i were designed and synthesized, their chemical structures were confirmed by IR, ¹H NMR, ¹³C NMR, MS spectral data and elemental analysis. IC₅₀ values for all prepared compounds to inhibit COX-1, COX-2 and 5-LOX enzymes were determined in vitro. Compounds 4a (IC₅₀ = 0.67 μM) and 4b (IC₅₀ = 0.58 μM) showed better COX-2 inhibitory activity than celecoxib (IC₅₀ = 0.87 μM) with selectivity index (SI = 8.41, 10.55 in sequent) relative to celecoxib (SI = 8.85). Also, compound 4a and 4b exhibited superior inhibitory activity against 5-LOX (IC₅₀ = 1.92, 2.31 μM) higher than zileuton (IC₅₀ = 2.43 μM). All target pyrazoles were screened for their ability to reduce nitric oxide production in LPS stimulated peritoneal macrophages. Compounds 4a, 4b, 4f and 4i displayed concentration dependent reduction and were screened for in vivo anti-inflammatory activity using carrageenan-induced rat paw edema assay. Compound 4f showed the highest anti-inflammatory activity (% edema inhibition = 15–20%) at all doses when compared to reference drug celecoxib (% edema inhibition = 15.7–17.5%). Docking studies were carried out to investigate the interaction of target compounds with COX-2 enzyme active site.     

Synthesis,molecular docking and anti-inflammatory screening of novel quinoline incorporated pyrazole derivatives using the Pfitzinger reaction II

In continuation of our study of novel quinolines with anti-inflammatory activity using the Pfitzinger reaction, several new quinoline derivatives were synthesized and tested for their anti-inflammatory and ulcerogenic effect. A docking study on the COX-2 binding pocket was carried out for the target compounds to rationalize the possible selectivity of them against COX-2 enzyme. The most active compounds (5a, 8a and 11a) were found to be superior to celecoxib. Compound 11a demonstrated the highest anti-inflammatory activity as well as the best binding profiles into the COX-2 binding site. Moreover, compounds 9c, 9e, 10a and 11a were devoid of ulcerogenic activity.     

New benzimidazothiazole derivatives as anti-inflammatory,antitumor active agents: Synthesis,in-vitro and in-vivo screening and molecular modeling studies

A new series of benzimidazothiazole derivatives has been synthesized. The structure of the products was confirmed by spectroscopic techniques such as IR, NMR and mass spectroscopy. The tested compounds were evaluated for their anti-inflammatory activity either in vitro through the COX enzyme inhibition assay, or in vivo through carrageenan paw edema technique. Results revealed that compound 25 and 29 represented the most active ones among the entire series with % inhibition 72.19, 72.07 for COX-1, and 87.46, 87.38 for COX-2, respectively. Interestingly, all synthesized compounds exhibited IC₅₀ values less than both reference drugs celecoxib and naproxen, indicating their superior potency. For compound 25, it showed about 340 and 198 times more potent than celecoxib and naproxen respectively as COX-1 inhibitor (IC₅₀ value 0.044 vs. 15.000 and 8.700 µM), and 10 and 115 times more potent than the same drugs as COX-2 inhibitor (IC₅₀ value 4.52 vs. 40.00 and 520.00 nM). The antitumor activity of the products was also evaluated and the results obtained are consistent with those obtained by the anti-inflammatory screening where compounds 25 and 29 proved to be the most active ones among the other compounds with %GI ranging from 31.5 to 62.5% and they exhibited the lowest IC₅₀ values as well. The ADMET analysis of the tested compounds was also performed in addition to the molecular modeling studies that included flexible alignment, surface and electrostatic maps in addition to the Lipinisk's rule of five.     

Novel 2,4-dichlorophenoxy acetic acid substituted thiazolidin-4-ones as anti-inflammatory agents: Design,synthesis and biological screening

A library of fourteen 2-imino-4-thiazolidinone derivatives (1a-1n) has been synthesized and evaluated for in vivo anti-inflammatory activity and effect on ex-vivo COX-2 and TNF–α expression. Compounds 1k (5-(2,4-dichloro-phenooxy)-acetic acid (3-benzyl-4-oxo-thiazolidin-2-ylidene)-hydrazide) and 1m (5-(2,4-dichloro-phenooxy)-acetic acid (3-cyclohexyl-4-oxo-thiazolidin-2-ylidene)-hydrazide) exhibited in vivo inhibition of 81.14% and 78.80% respectively after 5 h in comparison to indomethacin which showed 76.36% inhibition of inflammation without causing any damage to the stomach. Compound 1k showed a reduction of 68.32% in the level of COX-2 as compared to the indomethacin which exhibited 66.23% inhibition of COX-2. The selectivity index of compound 1k was found to be 29.00 in comparison to indomethacin showing selectivity index of 0.476. Compounds 1k and 1m were also found to significantly suppress TNF-α concentration to 70.10% and 68.43% in comparison to indomethacin which exhibited 66.45% suppression.     

Synthesis,biological evaluation and docking study of 1,3,4-thiadiazole-thiazolidinone hybrids as anti-inflammatory agents with dual inhibition of COX-2 and 15-LOX

Selective inhibition of both cyclooxygenase-2 (COX-2) and 15-lipooxygenase (15-LOX) may provide good strategy for alleviation of inflammatory disorders while minimizing side effects associated with current anti-inflammatory drugs. The present study describes the synthesis, full characterization and biological evaluation of a series of thiadiazole-thiazolidinone hybrids bearing 5-alk/arylidene as dual inhibitors of these enzymes. Our design was based on merging pharmacophores that exhibit portent anti-inflammatory activities in one molecular frame. 5-(4-hydroxyphenyl)-1,3,4-thiadiazol-2-amine (3) was efficiently synthesized, chloroacetylated and cyclized to give the key 4-thiazolidinone (5). Knovenagel condensation of 5 with different aldehydes afforded the final compounds 6a-m, 7, 8 and 9. These compounds were subjected to in vitro COX-1/COX-2, 15-LOX inhibition assays. Compounds (6a, 6f, 6i, 6l, 6m and 9) with promising potency (IC₅₀ = 70–100 nM) and selectivity index (SI = 220-55) were further tested for in vivo anti-inflammatory activity and effect on gastric mucosa. The most promising compound (6l) inhibits COX-2 enzyme at a nanomolar concentration (IC₅₀ = 70 nM, SI = 220) with simultaneous inhibition of 15-LOX (IC₅₀ = 11 µM). These results are comparable to the potency and selectivity of the standard drugs of both enzymes; celecoxib (COX-2 IC₅₀ = 49 nM, SI = 308) and zileuton (15-LOX IC₅₀ = 15 µM) in one construct. Interestingly three compounds (6a, 6l and 9) exhibited equivalent to or even higher than that of celecoxib in vivo anti-inflammatory activity at 3 h interval with good GIT safety profile. Molecular docking study conferred binding sites of these compounds on COX-2 and 15-LOX. Such type of compounds would represent valuable leads for further investigation and derivatization.     

Design,synthesis and evaluation of some pyrazolo[3,4-d]pyrimidine derivatives bearing thiazolidinone moiety as anti-inflammatory agents

Two new series of pyrazolo[3,4-d]pyrimidine bearing thiazolidinone moiety were designed and synthesized. The newly synthesized compounds were evaluated for their in vitro (COX-1 and COX-2) inhibitory assay. Compounds that showed promising COX-2 selectivity were further subjected to in vivo anti-inflammatory screening applying formalin induced paw edema (acute model) and cotton-pellet induced granuloma (chronic model) assays using celecoxib and diclofenac sodium as reference drugs. The histopathological and ulcerogenic potential were also determined. In vivo anti-inflammatory data showed that compounds 2, 6, 7d displayed anti-inflammatory activity higher than both references in the formalin induced paw edema model. On the other hand, compounds 2, 3d, 3e, 7b and 7d displayed anti-inflammatory activity greater than or nearly equivalent to diclofenac sodium in the cotton pellet-induced granuloma assay. Moreover, most of the tested compounds revealed good gastrointestinal safety profile. Collectively, compounds 2 and 7d were considered as promising candidates in managing both acute and chronic inflammation with safe gastrointestinal margin.     

Design & synthesis of novel oxazolone & triazinone derivatives and their biological evaluation as COX-2 inhibitors

A new series of oxazolones and triazinones were designed and synthesized and evaluated against both COX-1 and COX-2 enzymes. Full structure elucidation of the new derivatives was performed using microanalyses, IR, 1H NMR, 13C NMR and mass spectra. Most of the derivatives showed good inhibitory activity against COX-2 enzyme specifically compounds IIIc, IIIe, IVd and IVg with IC50 values 0.024, 0.019, 0.011 and 0.014 µM compared to celecoxib as reference drug with IC50 value of 0.05 µM. Altogether, these results indicate that these derivatives can be effective anti-inflammatory agents.