Design and synthesis of new 1,2-diaryl-4,5,6,7-tetrahydro-1H-benzo[d] imidazoles as selective cyclooxygenase (COX-2) inhibitors

A new series of 1,2-diaryl-4,5,6,7-tetrahydro-1H-benzo[d]imidazoles, possessing a methylsulfonyl pharmacophore, were synthesized to evaluate their biological activities as selective cyclooxygenase-2 (COX-2) inhibitors. In vitro COX-1 and COX-2 isozyme inhibition studies were carried out to acquire structure–activity relationship data with respect to the point that molecular modeling studies showed that designed compounds bind in the primary binding site such that the SO₂Me substituent at para-position of C-2 phenyl ring inserts into the 2° pocket present in COX-2 enzyme. COX-1 and COX-2 inhibition studies showed that all compounds were selective inhibitors of the COX-2 isozyme with IC₅₀ values in the highly potent 0.34–0.69?μM range, and COX-2 selectivity indexes in the 52.3–163.8 range. 1-(4-Fluorophenyl)-2-(4-(methylsulfonyl)phenyl)-4,5,6,7-tetrahydro-1H-benzo[d] imidazole was identified as the most potent (IC₅₀?=?0.34?μM), and selective (SI?=?163.8), COX-2 inhibitor among the synthesized compounds.     

Synthesis and biologic evaluation of new 3-phenoxyazetidin-2-one derivatives as selective cyclooxygenase-2 inhibitors

A new series of 3-phenoxyazetidin-2-ones (β-lactams) were designed and synthesized for the evaluation as selective cyclooxygenase-2 (COX-2) inhibitors. In vitro COX-1 and COX-2 inhibition studies showed that all compounds were selective inhibitors of the COX-2 isozyme with IC₅₀ values in the 0.054–0.095 μM range, and COX-2 selectivity indexes in the 228.47–355.6 range. Among the synthesized compounds, 1-(4-methoxyphenyl)-4-(4-(methylsulfonyl)phenyl)-3-phenoxyazetidin-2-one (4j) possessing methoxy group at the para position of N-1 phenyl ring exhibited the highest COX-2 inhibitory selectivity and potency even more potent than the reference drug celecoxib. Molecular modeling studies indicated that the methylsulfonyl pharmacophore group can be inserted into the secondary pocket of COX-2 active site.     

Design,Synthesis, and Biological Evaluation of New 2-Phenyl-4H-chromen-4-one Derivatives as Selective Cyclooxygenase-2 Inhibitors

In order to develop new selective COX-2 inhibitors, a new series of 2-phenyl-4H-chromen-4-one derivatives possessing a methylsulfonyl pharmacophore group at the para position of the C-4 phenyl ring were designed, synthesized, and evaluated for cyclooxygenase-2 inhibitory activity. In vitro COX-1/COX-2 isozyme inhibition structure-activity studies identified 3-(benzyloxy)-2-[4-(methylsulfonyl)phenyl]-4H-chromen-4-one (5d) as a potent COX-2 inhibitor (IC₅₀ = 0.07 μM) with a high COX-2 selectivity index (SI = 287.1) comparable to the reference drug celecoxib (COX-2 IC₅₀ = 0.06 μM; COX-2 SI = 405). A molecular modeling study where 3-(benzyloxy)-2-[4-(methylsulfonyl)phenyl]-4H-chromen-4-one (5d) was docked into the active site of COX-2 showed that the p-MeSO₂ substituent on the C-4 phenyl ring was well-oriented in the vicinity of the COX-2 secondary pocket (Arg⁵¹³, Val⁵²³, and His⁹⁰) and the carbonyl group of the chromene ring could interact with Ser⁵³⁰. The structure-activity data acquired indicated that the nature and size of the substituent on the C-3 chromene scaffold are important for COX-2 inhibitory activity. Our results also indicated that the chromene moiety constitutes a suitable template to design new COX-2 inhibitors.     

Design and syntheses of diarylisoxazoles: Novel inhibitors of cyclooxygenase‐2 (COX‐2) with analgesic‐antiinflammatory activity

A group of 4,5‐diphenylisoxazoles ( 11a–p ), 3,4‐diphenyl‐5‐trifluoromethylisoxazoles ( 15, 21 ), and 4,5‐diphenyl‐3‐methylsulfonamidoisoxazole ( 23 ) possessing a variety of substituents (H, F, MeS, MeSO, MeSO₂) at the para‐position of one of the phenyl rings were synthesized for evaluation as analgesic, and selective COX‐2 inhibitory antiinflammatory (AI), agents. Although the 4,5‐diphenylisoxazole group of compounds (11a–p) exhibited potent analgesic and AI activities, those compounds evaluated ( 11a, 11b, 11m ) were more selective inhibitors of COX‐1 than COX‐2, with the exception of 4‐(4‐methylsulphonylphenyl)‐5‐phenylisoxazole ( 11n ) that showed a modest COX‐2 selectivity index (SI) of 2.1. In contrast, 3‐(4‐methylsulphonylphenyl)‐4‐phenyl‐5‐trifluoromethylisoxazole ( 15 ), which retained good analgesic and AI activities, was a highly potent and selective COX‐2 inhibitor (COX‐1 IC₅₀ > 500 μM; COX‐2 IC₅₀ < 0.001 μM) with a COX‐2 SI of > 500,000, relative to the reference drug celecoxib (COX‐1 IC₅₀ = 22.9 μM; COX‐2 IC₅₀ = 0.0567 μM) with a COX‐2 SI of 404. The 3‐phenyl‐4‐(4‐methylsulphonylphenyl) regioisomer ( 21 ) was a less potent inhibitor (COX‐1 IC₅₀ = 252 μM; COX‐2 IC₅₀ = 0.2236 μM) with a COX‐2 SI of 1122, relative to the regioisomer ( 15 ). The related compound 4,5‐diphenyl‐3‐methylsulfonamidoisoxazole ( 23 ) exhibited similar (to 21 ) potency and COX‐2 selectivity (COX‐1 IC₅₀ > 200 μM; COX‐2 IC₅₀ = 0.226 μM) with an SI of 752. A molecular modeling (docking) study for the most potent, and selective, COX‐2 inhibitor (15) in the active site of the human COX‐2 enzyme showed the C‐5 CF₃ substituent is positioned 3.37 Å from the phenolic OH of Tyr³⁵⁵, and 6.91 Å from the Ser⁵³⁰ OH. The S‐atom of the MeSO₂ substituent is positioned deep (7.40 Å from the entrance) inside the COX‐2 secondary pocket (Val⁵²³). These studies indicate a C‐5 CF₃ ( 15, 21 ), or C‐3 NHSO₂Me ( 23 ), central isoxazole ring substituent is crucial to selective inhibition of COX‐2 for this class of compounds. Drug Dev. Res. 51:273–286, 2000. © 2001 Wiley‐Liss, Inc.     

Design,synthesis, and biological evaluation of new 1,4-diarylazetidin-2-one derivatives (β-lactams) as selective cyclooxygenase-2 inhibitors

A new series of 1,4-diarylazetidin-2-one derivatives (β-lactams) were designed and synthesized to evaluate their biological activities as selective cyclooxygenase-2 (COX-2) inhibitors. In vitro COX-1 and COX-2 inhibition studies showed that all compounds were selective inhibitors of the COX-2 isozyme with IC₅₀ values in the 0.05–0.11 µM range, and COX-2 selectivity indexes in the range of 170–703.7. Among the synthesized β-lactams, 3-methoxy-4-(4-(methylsulfonyl)phenyl)-1-(3,4,5-trimethoxyphenyl)azetidin-2-one ( 4j ) possessing trimethoxy groups at the N-1 phenyl ring exhibited the highest COX-2 inhibitory selectivity and potency, even more potent than the reference drug celecoxib. The analgesic activity of the synthesized compounds was also determined using the formalin test. Compound 4f displayed the best analgesic activity among the synthesized molecules. Molecular modeling studies indicated that the methylsulfonyl pharmacophore group can be inserted into the secondary pocket of the COX-2 active site for interactions with Arg⁵¹³. The structure–activity data acquired indicate that the β-lactam ring moiety constitutes a suitable scaffold to design new 1,4-diarylazetidin-2-ones with selective COX-2 inhibitory activity.     

1,3‐Bis(aryloxy)propan‐2‐ols as potential antileishmanial agents

We describe herein the synthesis and antileishmanial activity of 1,3‐bis(aryloxy)propan‐2‐ols. Five compounds ( 2 , 3 , 13 , 17 , and 18 ) exhibited an effective antileishmanial activity against stationary promastigote forms of Leishmania amazonensis (IC₅₀ < 15.0 μm ), and an influence of compound lipophilicity on activity was suggested. Most of the compounds were poorly selective, as they showed toxicity toward murine macrophages, except 17 and 18 , which presented good selective indexes (SI ≥ 10.0). The five more active compounds ( 2 , 3 , 13 , 17 , and 18 ) were selected for the treatment of infected macrophages, and all of them were able to reduce the number of internalized parasites by more than 80%, as well as the number of infected macrophages by more than 70% in at least one of the tested concentrations. Altogether, these results demonstrate the potential of these compounds as new hits of antileishmanial agents and open future possibilities for them to be tested in in vivo studies.     

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.     

1,2-Diaryl-2-hydroxyiminoethanones as Dual COX-1 and β-Amyloid Aggregation Inhibitors: Biological Evaluation and In Silico Study

To find out new agents for treating inflammatory-involved diseases such as Alzheimer's disease, a series of 1,2-diaryl-2-hydroxyiminoethanones containing vicinal diaryl pharmacophore of COX inhibitors were tested by a set of in vitro, in vivo, and computational studies. The in vivo study of compounds indicated their prominent anti-inflammatory ability at the doses of 10 and 20 mg/kg comparable to celecoxib (10 mg/kg). Further in vitro COX-1/COX-2 evaluations revealed that 4-methoxy derivative 3 had a high selective COX-1 inhibitory activity (COX-1, IC₅₀ = 0.12 μm , SI > 833). To evaluate their potential use against Alzheimer's disease, in vitro evaluation of β-amyloid fibril formation using Aβ_(1–40) and Aβ_(1–42) peptides was performed. The evaluation of their antiaggregation ability gave impressive results and comparable to rifampicin and indomethacin. Conformational study of compound 3 and subsequent docking of its restrained analogs on both active sites of COX-1 and COX-2 could provide a proof of its COX-1 selectivity as well as molecular dynamic simulation could elucidate and give more insight into the amyloid disaggregation mechanisms leading to rational design of inhibitors.     

Distinction of microsomal prostaglandin E synthase-1 (mPGES-1) inhibition from cyclooxygenase-2 inhibition in cells using a novel, selective mPGES-1 inhibitor

Inflammation-induced microsomal prostaglandin E synthase-1 (mPGES-1) is the terminal enzyme that synthesizes prostaglandin E₂ (PGE₂) downstream of cyclooxygenase-2 (COX-2). The efficacy of nonsteroidal anti-inflammatory drugs and COX-2 inhibitors in the treatment of the signs and symptoms of osteoarthritis, rheumatoid arthritis and inflammatory pain, largely attributed to the inhibition of PGE₂ synthesis, provides a rationale for exploring mPGES-1 inhibition as a potential novel therapy for these diseases. Toward this aim, we identified PF-9184 as a novel mPGES-1 inhibitor. PF-9184 potently inhibited recombinant human (rh) mPGES-1 (IC₅₀ = 16.5 ± 3.8 nM), and had no effect against rhCOX-1 and rhCOX-2 (>6500-fold selectivity). In inflammation and clinically relevant biological systems, mPGES-1 expression, like COX-2 expression was induced in cell context- and time-dependent manner, consistent with the kinetics of PGE₂ synthesis. In rationally designed cell systems ideal for determining direct effects of the inhibitors on mPGES-1 function, but not its expression, PF-9184 inhibited PGE₂ synthesis (IC₅₀ in the range of 0.5-5 μM in serum-free cell and human whole blood cultures, respectively) while sparing the synthesis of 6-keto-PGF_1α (PGF_1α) and PGF_2α. In contrast, as expected, the selective COX-2 inhibitor, SC-236, inhibited PGE₂, PGF_1α and PGF_2α synthesis. This profile of mPGES-1 inhibition, distinct from COX-2 inhibition in cells, validates mPGES-1 as an attractive target for therapeutic intervention.     

Novel 1,3‐oxazine‐tetrazole hybrids as mushroom tyrosinase inhibitors and free radical scavengers: Synthesis,kinetic mechanism,and molecular docking studies

A variety of 5‐(2H‐tetrazol‐5‐yl)‐4‐thioxo‐2‐(substituted phenyl)‐4,5‐dihydro‐1,3‐oxazin‐6‐ones ( 3a–k ) have been synthesized from 1,3‐oxazine‐5‐carbonitriles ( 2a–k ). The protocol represents an efficient, facile, and novel route from easily available precursors to unprecedented structures that share 1,3‐oxazine and tetrazole motifs of utmost value. All the synthesized compounds ( 3a–k ) were evaluated for their inhibitory potential against mushroom tyrosinase. Results revealed that all examined 1,3‐oxazine‐tetrazole hybrids exhibited significant tyrosinase inhibitory activity while compound 3d having 2‐bromophenyl moiety was the most potent among the series with IC₅₀ value 0.0371 ± 0.0018 μM as compared to the reference kojic acid (IC₅₀ = 16.832 ± 0.73 μM). Inhibitory kinetics showed that compound 3d behaves as a competitive inhibitor. The molecular docking analysis was performed against target protein to investigate the binding mode. Moreover, compounds 3j and 3k displayed superior DPPH radical scavenging activity than other analogues.     

<Emphasis Type="Italic">In vitro</Emphasis> anti-inflammatory activity of carvacrol: Inhibitory effect on COX-2 catalyzed prostaglandin E<Subscript>2</Subscript> biosynthesisb

Possible anti-inflammatory effect of carvacrol was evaluated by in vitro cyclooxygenase-2 (COX-2) assay. Carvacrol inhibited production of prostaglandin E₂ catalysed by COX-2 with an IC₅₀ value of 0.8 μM what is practically the same concentration as the IC₅₀ obtained for the standard inhibitors indomethacin and NS-398 with values of 0.7 μM and 0.8 μM, respectively. The COX-1 was inhibited approximately at the same rate (IC₅₀ of 0.7 μM for carvacrol), which suggests non-selective inhibition of both enzyme isoforms. The results of the study demonstrate possible anti-inflammatory potential of this compound due to the inhibition of inducible COX-2 isoform.     

Discovery of cyclooxygenase inhibitors from medicinal plants used to treat inflammation

Eleven authenticated botanicals used in the traditional Chinese medicine Huo-Luo-Xiao-Ling Dan were screened for ligands to cyclooxygenase (COX) using pulsed ultrafiltration liquid chromatography–mass spectrometry, and a mass spectrometry-based enzyme assay was used to determine the concentration of each of 17 ligands that inhibited COX-1 or COX-2 by 50% (IC₅₀). Acetyl-11-keto-β-boswellic acid, β-boswellic acid, acetyl-α-boswellic acid, acetyl-β-boswellic acid, and betulinic acid were COX-1 selective inhibitors with IC₅₀ values of approximately 10 μM. Senkyunolide O and cryptotanshinone were COX-2 selective inhibitors with IC₅₀ values of 5 μM and 22 μM, respectively. Roburic acid and phenethyl-trans-ferulate inhibited COX-1 and COX-2 equally. COX inhibition and the IC₅₀ values of most of these natural product ligands have not been reported previously.     

Mitochondrial toxicity of selective COX-2 inhibitors via inhibition of oxidative phosphorylation (ATP synthesis) in rat liver mitochondria

Cyclooxygenase-2 (COX-2) inhibitors (coxibs) are non-steroidal anti-inflammatory drugs (NSAIDs) designed to selectively inhibit COX-2. However, drugs of this therapeutic class are associated with drug induced liver injury (DILI) and mitochondrial injury is likely to play a role. The effects of selective COX-2 inhibitors on inhibition of oxidative phosphorylation (ATP synthesis) in rat liver mitochondria were investigated. The order of potency of inhibition of ATP synthesis was: lumiracoxib (IC₅₀: 6.48 ± 2.74 μM) > celecoxib (IC₅₀: 14.92 ± 6.40 μM) > valdecoxib (IC₅₀: 161.4 ± 28.6 μM) > rofecoxib (IC₅₀: 238.4 ± 79.2 μM) > etoricoxib (IC₅₀: 405.1 ± 116.3 μM). Mechanism based inhibition of ATP synthesis (K_inact 0.078 min^− 1 and K_I 21.46 μM and K_inact/K_I ratio 0.0036 min^− 1 μM^− 1) was shown by lumiracoxib and data suggest that the opening of the MPT pore may not be the mechanism of toxicity. A positive correlation (with r² = 0.921) was observed between the potency of inhibition of ATP synthesis and the log P values. The in vitro metabolism of coxibs in rat liver mitochondria yielded for each drug substance a major single metabolite and identified a hydroxy metabolite with each of the coxibs and these metabolites did not alter the inhibition profile of ATP synthesis of the parent compound. The results suggest that coxibs themselves could be involved in the hepatotoxic action through inhibition of ATP synthesis.     

Pyridopyrimidinone Derivatives as Potent and Selective c-Jun N-Terminal Kinase (JNK) Inhibitors

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Involvement of endothelial thromboxane A2 in the vasoconstrictor response induced by 15-E2t-isoprostane in isolated human umbilical vein

The present study was undertaken to evaluate the contractile response of several E- and F-ring isoprostanes (IsoP) in human umbilical vein (HUV) and to investigate the role of the endothelium on the effect of 15-E_2t-IsoP, the most potent vasoconstrictor isoprostane, in human vessels. HUV rings with or without endothelium were suspended in an organ bath for recording the isometric tension in response to different agonists. The inhibitors to be evaluated were applied 30 min before the addition of the agonist. All of the compounds tested produced concentration-dependent contractions when tested on HUV rings with endothelium. Although these compounds were equieffective, significant differences were observed in their potency, with U46619 being the most potent followed by 15-E_2t-IsoP > 15-E_1t-IsoP = 15-F_2t-IsoP > 15-F_1t-IsoP = 9-epi-15-F_2t-IsoP in descending rank order of potency. 15-E_2t-IsoP was the most potent of the isoprostanes evaluated and, therefore, the one employed in the present study. When intact endothelium HUV rings were used, 15-E_2t-IsoP-induced contraction was unaffected by the endothelin-converting enzyme inhibitor, phosphoramidon (10 μM), suggesting that short-term endothelin-1 release is not involved in this response. However, the non-selective cyclooxygenase (COX) inhibitor, indomethacin (10 and 30 μM), and the COX-2 selective inhibitor, NS-398 (3, 10 and 30 μM) produced inhibitory effects on 15-E_2t-IsoP-induced contraction of HUV rings with endothelium. These results indicate that COX-derived contractile prostanoids are involved in this effect. Furthermore, the apparent pK _b values estimated for indomethacin (5.5) and NS-398 (5.4) suggest that the prostanoids involved are derived from the COX-2 isoenzyme pathway. On HUV rings with endothelium, the phospholipase A₂ inhibitor, oleyloxyethyl phosphorylcholine (30 and 100 μM), induced an inhibitory effect on 15-E_2t-IsoP-induced contraction, suggesting that the phospholipase A₂ pathway is also involved in this effect. In addition, the thromboxane A₂ synthase inhibitor furegrelate (10 and 30 μM) also inhibited 15-E_2t-IsoP-induced contraction of HUV rings with endothelium, indicating that thromboxane A₂ is one of the contractile prostanoids involved in this response. Endothelium denudation clearly diminished the vasoconstrictor potency of 15-E_2t-IsoP, demonstrating that the endothelium releases a vasoconstrictor factor in response to 15-E_2t-IsoP. The absence of an inhibitory effect at the highest concentration of furegrelate (30 μM) on 15-E_2t-IsoP-induced contraction of HUV rings without endothelium suggested that endothelium is the source of thromboxane A₂. We conclude that prostanoids derived from the COX-2 isoenzyme pathway participate in 15-E_2t-IsoP-induced vasoconstriction of isolated HUV rings. Our results also indicate that endothelial thromboxane A₂ is one of the prostanoids involved in this effect.     

Synthesis and structure-activity relationship of novel, highly potent metharyl and methcycloalkyl cyclooxygenase-2 (COX-2) selective inhibitors

A novel series of benzo-1,3-dioxolane metharyl derivatives was synthesized and evaluated for cyclooxygenase-2 (COX-2) and cyclooxygenase-1 (COX-1) inhibition in human whole blood (HWB). In the present study, structure-activity relationships (SAR) in the metharyl analogues were investigated. The spacer group and substitutions in the spacer group were found to be quite important for potent COX-2 inhibition. Compounds in which a methylene group (8a-c), carbonyl group (12a-c), or methylidene group (7a-c) connected cycloalkyl groups to the central benzo-1,3-dioxolane template were found to be potent and selective COX-2 inhibitors. Aryl-substituted compounds linked to the central ring by either a methylene or a carbonyl spacer resulted in potent, highly selective COX-2 inhibitors. In this series of substituted-(2H-benzo[3,4-d]1,3-dioxolan-5-yl))-1-(methylsulfonyl)benzene compounds, SAR studies demonstrated that substitution at the 3-position of the aryl group optimized COX-2 selectivity and potency, whereas substitution at the 4-position attenuated COX-2 inhibition. Mono- or difluoro substitution at meta position(s), as in 22c and 22h, was advantageous for both in vitro COX-2 potency and selectivity (e.g., COX-2 IC(50) for 22c = 1 microM and COX-1 IC(50) for 22c = 20 microM in HWB assay). Several novel compounds in the (2H-benzo[3,4-d]1,3-dioxolan-5-yl))-1-(methylsulfonyl)benzene series, as shown in structures 7c, 8a, 12a, 21c, 22c, 22e, and 22h, selectively inhibited COX-2 activity by 40-50% at a test concentration of 1 microM in an in vitro HWB assay.     

Anti-oxidative and inhibitory activities on nitric oxide (NO) and prostaglandin E<Subscript>2</Subscript> (COX-2) production of flavonoids from seeds of <Emphasis Type="Italic">Prunus tomentosa</Emphasis> Thunberg

Chemical investigation of the 80% Me₂CO extract from the seeds of Prunus tomentosa led to the isolation and identification of six flavonoids: kaempferol (1), kaempferol 3-O-α-L-rhamnopyranoside (2; afzelin), kaempferol 3-O-β-D-(6-acetyl)-glucopyranosyl(1→4)-α-L-rhamnopyranoside (3; multiflorin A), kaempferol 3-O-β-D-glucopyranosyl(1→4)-α-L-rhamnopyranoside (4; multiflorin B), quercetin 3-O-α-L-rhamnopyranoside (5; quercitrin), and quercetin 3-O-β-D-glucopyranosyl (1→4)-α-L-rhamnopyranoside (6; multinoside A). Anti-oxidative and inhibitory activities on nitric oxide (NO) and prostaglandin E₂ production in interferon-γ (INF-γ) and lipopolysaccharide (LPS)-activated RAW 264.7 cells in vitro (COX-2) of the isolated compounds were evaluated. Compounds 1, 5, and 6 exhibited potent anti-oxidative activity in the DPPH radical scavenging assay with IC₅₀ values of 57.2, 59.4, and 54.3 μg/mL respectively. The positive control, ascorbic acid, had an IC₅₀ of 55.5 μg/mL. Compounds 1, 5, and 6 also reduced COX-2 levels in a dose dependent manner with IC₅₀ values of 10.2, 8.7, and 9.6 μg/mL respectively, with the positive control, indomethacin, having an IC₅₀ of 5.1 μg/mL. All six compounds inhibited NO production in a dose dependent manner with IC₅₀ values of 35.1, 42.8, 40.0, 44.8, 43.7, and 43.9 μg/mL respectively, while the positive control, L-NMMA, had an IC₅₀ of 42.1 μg/mL.     

Rational drug discovery: Ellagic acid as a potent dual‐target inhibitor against hepatitis C virus genotype 3 (HCV G3) NS3 enzymes

Structure‐based virtual screening (SBVS) has served as a popular strategy for rational drug discovery. In this study, we aimed to discover novel benzopyran‐based inhibitors that targeted the NS3 enzymes (NS3/4A protease and NS3 helicase) of HCV G3 using a combination of in silico and in vitro approaches. With the aid of SBVS, six novel compounds were discovered to inhibit HCV G3 NS3/4A protease and two phytochemicals (ellagic acid and myricetin) were identified as dual‐target inhibitors that inhibited both NS3/4A protease and NS3 helicase in vitro (IC₅₀ = 40.37 ± 5.47 nm and 6.58 ± 0.99 µm , respectively). Inhibitory activities against the replication of HCV G3 replicons were further assessed in a cell‐based system with four compounds showed dose‐dependent inhibition. Compound P8 was determined to be the most potent compound from the cell‐based assay with an EC₅₀ of 19.05 µm . The dual‐target inhibitor, ellagic acid, was determined as the second most potent (EC₅₀ = 32.37 µm ) and the most selective in its inhibitory activity against the replication of HCV replicons, without severely affecting the viability of the host cells (selectivity index > 6.18).     

Design,synthesis, and biological evaluation of new pyrazoloquinazoline derivatives as dual COX-2/5-LOX inhibitors

A new series of pyrazoloquinazoline derivatives equipped with different chalcones was designed, synthesized, and identified through ¹H nuclear magnetic resonance (NMR), ¹³C NMR, and infrared spectroscopic techniques. Our design strategy of the quinazolinone-privileged scaffold as a new scaffold was based on merging pharmacophores previously reported to exhibit cyclooxygenase-2 (COX-2)/5-lipoxygenase (5-LOX) inhibitory activity. All the newly synthesized derivatives were biologically evaluated for COX and 5-LOX inhibitory activity and COX-2 selectivity, using celecoxib and zileuton as reference drugs, as they exhibited promising anti-inflammatory activity. Compound 3j was found to be the most promising derivative, with IC₅₀ values of 667 and 47 nM against COX-1 and COX-2, respectively, which are superior to that of celecoxib (IC₅₀ value against COX-2 = 95 nM), showing an SI of 14.2 that was much better than celecoxib. Compounds 3f and 3h exhibited COX-1 inhibition, with IC₅₀ values of 1,485 and 684 nM, respectively. The synthesized compounds showed a significant inhibitory activity against 5-LOX, with IC₅₀ values ranging from 0.6 to 4.3 µM, where compounds 3f and 3h were found to be the most potent derivatives, with IC₅₀ values of 0.6 and 1.0 µM, respectively, in comparison with that of zileuton (IC₅₀ = 0.8 µM). These promising derivatives, 3f , 3h , and 3j , were further investigated in vivo for anti-inflammatory, gastric ulcerogenic effects, and prostaglandin production (PGE2) in rat serum. The molecular docking studies concerning the binding sites of COX-2 and 5-LOX revealed similar orientation, compared with reported inhibitors, which encouraged us to design new leads targeting COX-2 and 5-LOX as dual inhibitors, as a new avenue in anti-inflammatory therapy.     

2-(Hetero(aryl)methylene)hydrazine-1-carbothioamides as Potent Urease Inhibitors

A small series of 2-(hetero(aryl)methylene) hydrazine-1-carbothioamides including two aryl derivatives was synthesized and tested for their inhibitory activity against urease. Compound (E)-2-(Furan-2-ylmethylene) hydrazine-1-carbothioamide (3f) , having a furan ring, was the most potent inhibitor of urease with an IC₅₀ value of 0.58 μm . Molecular modeling was carried out through docking the designed compounds into the urease binding site to predict whether these derivatives have analogous binding mode to the urease inhibitors. The study revealed that all of the tested compounds bind with both metal atoms at the active site of the enzyme. The aromatic ring of the compounds forms ionic interactions with the residues, Ala(440), Asp(494), Ala(636), and Met(637).