Design, synthesis and biological screening of some novel celecoxib and etoricoxib analogs with promising COX-2 selectivity, anti-inflammatory activity and gastric safety profile

New N-Substituted-1,2,4-triazole Derivatives of Pyrrolo[3,4-d]pyridazinone with Significant Anti-Inflammatory Activity-Design, Synthesis and Complementary In Vitro, Computational and Spectroscopic Studies

Regarding that the chronic use of commonly available non-steroidal and anti-inflammatory drugs (NSAIDs) is often restricted by their adverse effects, there is still a current need to search for and develop new, safe and effective anti-inflammatory agents. As a continuation of our previous work, we designed and synthesized a series of 18 novel N-substituted-1,2,4-triazole-based derivatives of pyrrolo[3,4-d]pyridazinone 4a-c-9a-c. The target compounds were afforded via a convenient way of synthesis, with good yields. The executed cell viability assay revealed that molecules 4a-7a, 9a, 4b-7b, 4c-7c do not exert a cytotoxic effect and were qualified for further investigations. According to the performed in vitro test, compounds 4a-7a, 9a, 4b, 7b, 4c show significant cyclooxygenase-2 (COX-2) inhibitory activity and a promising COX-2/COX-1 selectivity ratio. These findings are supported by a molecular docking study which demonstrates that new derivatives take position in the active site of COX-2 very similar to Meloxicam. Moreover, in the carried out in vitro evaluation within cells, the title molecules increase the viability of cells pre-incubated with the pro-inflammatory lipopolysaccharide and reduce the level of reactive oxygen and nitrogen species (RONS) in induced oxidative stress. The spectroscopic and molecular modeling study discloses that new compounds bind favorably to site II(m) of bovine serum albumin. Finally, we have also performed some in silico pharmacokinetic and drug-likeness predictions. Taking all of the results into consideration, the molecules belonging to series a (4a-7a, 9a) show the most promising biological profile.

New Benzoxazole Derivatives as Antiprotozoal Agents: In Silico Studies, Synthesis, and Biological Evaluation

Background. Benzoxazole derivatives have different biological activities. In pursuit of designing novel chemical entities with antiprotozoal and antimicrobial activities, benzoxazolyl aniline was utilized as a privileged scaffold of a series of (3-benzoxazole-2-yl) phenylamine derivatives, 3-benzoxazoloyl acetamide, and butyramide derivatives. Methods. These novel analogs were synthesized in straightforward simple chemistry without any quantitative chromatographic separations in reasonable yields. The biological evaluation of all target compounds as potential antimalarial, antileishmanial, antitrypanosomal, and antimicrobial agents was performed by various well-established cell-based methods. Results. Compounds 6d and 5a showed promising biological screening data. The amidation of 3-benzoxazolyl aniline 1 with the chloroacetyl functional group resulted in a good antimalarial activity and showed moderate inhibitory activities against leishmanial and trypanosomal spp. Moreover, chloroacetyl functionalization of benzoxazolyl aniline serves as a good early goal for constructing and synthesizing new antimicrobial and antiprotozoal agents. The molecular docking study rationalizes the relative inhibitory activity of compound 5a as an antimalarial agent with the deregulation of PfPNP activity which has emerged as a major mechanism of these targets.

A New CDK2 Inhibitor with 3-Hydrazonoindolin-2-One Scaffold Endowed with Anti-Breast Cancer Activity: Design, Synthesis, Biological Evaluation, and In Silico Insights

Background: Cyclin-dependent kinases (CDKs) regulate mammalian cell cycle progression and RNA transcription. Based on the structural analysis of previously reported CDK2 inhibitors, a new compound with 3-hydrazonoindolin-2-one scaffold (HI 5) was well designed, synthesized, and biologically evaluated as a promising anti-breast cancer hit compound. Methods: The potential anti-cancerous effect of HI 5 was evaluated using cytotoxicity assay, flow cytometric analysis of apoptosis and cell cycle distribution, ELISA immunoassay, in vitro CDK2/cyclin A2 activity, and molecular operating environment (MOE) virtual docking studies. Results: The results revealed that HI 5 exhibits pronounced CDK2 inhibitory activity and cytotoxicity in human breast cancer MCF-7 cell line. The cytotoxicity of HI 5 was found to be intrinsically mediated apoptosis, which in turn, is associated with low Bcl-2 expression and high activation of caspase 3 and p53. Besides, HI 5 blocked the proliferation of the MCF-7 cell line and arrested the cell cycle at the G2/M phase. The docking studies did not confirm which one of geometric isomers (syn and anti) is responsible for binding affinity and intrinsic activity of HI 5. However, the molecular dynamic studies have confirmed that the syn-isomer has more favorable binding interaction and thus is responsible for CDK2 inhibitory activity. Discussion: These findings displayed a substantial basis of synthesizing further derivatives based on the 3-hydrazonoindolin-2-one scaffold for favorable targeting of breast cancer.

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.

Design, synthesis, and pharmacological evaluation of novel and selective COX-2 inhibitors based on bumetanide scaffold

Herein, we describe the design and synthesis of new benzenesulfonamide derivatives as selective COX-2 inhibitors based on bumetanide scaffold. Benzenesulfonamides bearing both the pyrazole 6b and the triazoles 9a, 9c were good inhibitors of COX-2 with IC50 values of 0.32, 0.28 and 0.17 µM, respectively. These benzenesulfonamides 6b, 9a and 9c exhibited a higher selectivity index than the reference drug celecoxib. Molecular modeling study showed that incorporation of bumetanide led to a unique binding mode that is most likely the reason for the observed significant COX-2 selectivity. The anti-inflammatory activity of synthesized compounds revealed that triazoles 9a and 9c demonstrated higher efficacy than celecoxib upon using in vivo carrageenan-induced rat paw edema model. Most of the prepared compounds possess low ulcerogenic potential when administered orally. Therefore, these compounds have a great potential to be developed as safe therapeutics for inflammation, pain, and other diseases where COX-2 plays important role in their pathophysiology.

Sulfonamide-based 4-anilinoquinoline derivatives as novel dual Aurora kinase (AURKA/B) inhibitors: Synthesis, biological evaluation and in silico insights

Aurora kinases (AURKs) were identified as promising druggable targets for targeted cancer therapy. Aiming at the development of novel chemotype of dual AURKA/B inhibitors, herein we report the design and synthesis of three series of 4-anilinoquinoline derivatives bearing a sulfonamide moiety (5a-d, 9a-d and 11a-d). The % inhibition of AURKA/B was determined for all target quinolines, then compounds showed more than 50% inhibition on either of the enzymes, were evaluated further for their IC₅₀ on the corresponding enzyme. In particular, compound 9d displayed potent AURKA/B inhibitory activities with IC₅₀ of 0.93 and 0.09 µM, respectively. Also, 9d emerged as the most efficient anti-proliferative analogue in the US-NCI anticancer assay toward the NCI 60 cell lines panel, with broad spectrum activity against different cell lines from diverse cancer subpanels. Docking studies, confirmed that, the sulfonamide SO₂ oxygen was involved in a hydrogen bond with Lys162 and Lys122 in AURKA and AURKB, respectively, whereas, the sulfonamide NH could catch hydrogen bond interaction with the surrounding amino acid residues Lys141, Glu260, and Asn261 in AURKA and Lys101, Glu177, and Asp234 in AURKB. Furthermore, N1 nitrogen of the quinoline scaffold formed an essential hydrogen bond with the hinge region key amino acids Ala213 and Ala173 in AURKA and AURKB, respectively.

Design, synthesis and molecular docking of benzophenone conjugated with oxadiazole sulphur bridge pyrazole pharmacophores as anti inflammatory and analgesic agents

The prostaglandins (PG) a group of physiologically active lipid compounds having diverse hormone like effects are important mediators of the body's response to pain and inflammation, and are formed from essential fatty acids found in cell membranes. This reaction is catalyzed by cyclooxygenase, a membrane associated enzyme occurring in two isoforms, COX-1 and COX-2. Nonsteroidal anti-inflammatory drugs (NSAIDs) act by inhibiting the activity of COX. In view of this, a series of novel benzophenones conjugated with oxadiazole sulphur bridge pyrazole moiety 8a-l were designed, synthesized, characterized and subsequently evaluated for anti-inflammatory and analgesic property. The investigation of novel analogues 8a-l for potential anti-inflammatory activity showed high levels of COX-1 and COX-2 inhibitory activity. Among the series, compound 8i with electron withdrawing fluoro group at the para position of the benzoyl ring of benzophenone was characterized by highest IC₅₀ values for both COX-1 and COX-2 inhibition, which is comparable to the standard drug. Further, molecular docking studies have been performed for the potent compound.

Discovery of new non-acidic lonazolac analogues with COX-2 selectivity as potent anti-inflammatory agents

Herein, the design and synthesis of some novel 1,3,4-trisubstituted pyrazole derivatives was carried out through the structural modification of lonazolac. All the synthesized compounds were investigated for in vitro COX-1 & COX-2 inhibition and in vivo anti-inflammatory activity by a carrageenan rat paw edema model. Among them, the chalcones 2a and 2b were the most COX-2 selective derivatives (S.I. = 8.22 and 9.31, respectively) and revealed very good in vivo anti-inflammatory potency. Similarly, the compounds 4a, 6b, 7a and 8a exhibited good COX-2 selectivity and in vivo anti-inflammatory activity. The active compounds were selected to further investigate their ulcerogenic activity, and they were found to be less ulcerogenic (ulcer indices = 2.4-8.4) as compared to indomethacin (ulcer index = 17.6) and nearly as ulcerogenic as celecoxib (ulcer index = 8.1). Moreover, histological studies were performed to evaluate the safety of these compounds on the stomach, liver and kidney. Furthermore, a docking study was performed to determine possible binding of the most active compounds 2a and 2b, which showed high docking scores (-9.461 and -7.962 kcal mol^-1, respectively) that were comparable to that of celecoxib (-8.692 kcal mol^-1).

A one-pot metal-free protocol for the synthesis of chalcogenated furans from 1,4-enediones and thiols

Transition-metal-free synthesis of chalcogenated furans through the sequential thiol-Michael/Paal–Knorr reaction of 1,4-enediones in the presence of a catalytic amount of p-toluene sulfonic acid has been developed.

Synthesis, molecular docking, and pharmacological evaluation of N-(2-(3,5-dimethoxyphenyl)benzoxazole-5-yl)benzamide derivatives as selective COX-2 inhibitors and anti-inflammatory agents

A series of N-(2-(3,5-dimethoxyphenyl)benzoxazole-5-yl)benzamide derivatives (3am) was synthesized and evaluated for their in vitro inhibitory activity against COX-1 and COX-2. The compounds with considerable in vitro activity (IC₅₀  < 1 μM) were evaluated in vivo for their anti-inflammatory potential by the carrageenan-induced rat paw edema method. Out of 13 newly synthesized compounds, 3a, 3b, 3d, 3g, 3j, and 3k were found to be the most potent COX-2 inhibitors in the in vitro enzymatic assay, with IC₅₀ values in the range of 0.06-0.71 μM. The in vivo anti-inflammatory activity of these six compounds (3a, 3b, 3d, 3g, 3j, and 3k) was assessed by the carrageenan-induced rat paw edema method. Compounds 3d (84.09%), 3g (79.54%), and 3a (70.45%) demonstrated significant anti-inflammatory activity compared to the standard drug ibuprofen (65.90%) and were also found to be safer than ibuprofen, by ulcerogenic studies. A docking study was done using the crystal structure of human COX-2, to understand the binding mechanism of these inhibitors to the active site of COX-2.

Pharmacological Potential and Synthetic Approaches of Imidazo[4,5-b]pyridine and Imidazo[4,5-c]pyridine Derivatives

The structural resemblance between the fused imidazopyridine heterocyclic ring system and purines has prompted biological investigations to assess their potential therapeutic significance. They are known to play a crucial role in numerous disease conditions. The discovery of their first bioactivity as GABA_A receptor positive allosteric modulators divulged their medicinal potential. Proton pump inhibitors, aromatase inhibitors, and NSAIDs were also found in this chemical group. Imidazopyridines have the ability to influence many cellular pathways necessary for the proper functioning of cancerous cells, pathogens, components of the immune system, enzymes involved in carbohydrate metabolism, etc. The collective results of biochemical and biophysical properties foregrounded their medicinal significance in central nervous system, digestive system, cancer, inflammation, etc. In recent years, new preparative methods for the synthesis of imidazopyridines using various catalysts have been described. The present manuscript to the best of our knowledge is the complete compilation on the synthesis and medicinal aspects of imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines reported from the year 2000 to date, including structure–activity relationships.