Design, synthesis and biological evaluation of novel diphenylthiazole-based cyclooxygenase inhibitors as potential anticancer agents

Discovery and optimization of 2,3-diaryl-1,3-thiazolidin-4-one-based derivatives as potent and selective cytotoxic agents with anti-inflammatory activity

Several studies have indicated the potential therapeutic outcomes of combining selective COX-2 inhibitors with tubulin-targeting anticancer agents. In the current study, a novel series of thiazolidin-4-one-based derivatives (7a-q) was designed by merging the pharmacophoric features of some COXs inhibitors and tubulin polymerization inhibitors. Compounds 7a-q were synthesized and evaluated for their cytotoxic activity against MCF7, HT29, and A2780 cancer cell lines (IC50 = 0.02-17.02 μM). The cytotoxicity of 7a-q was also assessed against normal MRC5 cells (IC50 = 0.47-13.46 μM). Compounds 7c, 7i, and 7j, the most active in the MTT assay, significantly reduced the number of HT29 colonies compared to the control. Compounds 7c, 7i, and 7j also induced significant decreases in the tumor volumes and masses in Ehrlich solid carcinoma-bearing mice compared to the control. The three compounds also exhibited significant anti-HT29 migration activity in the wound-healing assay. They have also induced cell cycle arrest in HT29 cells at the S and G2/M phases. In addition, they induced significant increases in both early and late apoptotic events in HT29 cells compared to the control, where 7j showed the highest effect. On the other hand, compound 7j (1 μM) displayed weak inhibitory activity against tubulin polymerization compared to colchicine (3 μM). On the other hand, compounds 7a-q inhibited the activity of COX-2 (IC50 = 0.42-29.11 μM) compared to celecoxib (IC50 = 0.86 μM). In addition, 7c, 7i, and 7j showed moderate inhibition of inflammation in rats compared to indomethacin, with better GIT safety profiles. Molecular docking analysis revealed that 7c, 7i, and 7j have higher binding free energies towards COX-2 than COX-1. These above results suggested that 7j could serve as a potential anticancer drug candidate.

Design and Development of COX-II Inhibitors: Current Scenario and Future Perspective

Innate inflammation beyond a threshold is a significant problem involved in cardiovascular diseases, cancer, and many other chronic conditions. Cyclooxygenase (COX) enzymes are key inflammatory markers as they catalyze prostaglandins production and are crucial for inflammation processes. While COX-I is constitutively expressed and is generally involved in "housekeeping" roles, the expression of the COX-II isoform is induced by the stimulation of different inflammatory cytokines and also promotes the further generation of pro-inflammatory cytokines and chemokines, which affect the prognosis of various diseases. Hence, COX-II is considered an important therapeutic target for drug development against inflammation-related illnesses. Several selective COX-II inhibitors with safe gastric safety profiles features that do not cause gastrointestinal complications associated with classic anti-inflammatory drugs have been developed. Nevertheless, there is mounting evidence of cardiovascular side effects from COX-II inhibitors that resulted in the withdrawal of market-approved anti-COX-II drugs. This necessitates the development of COX-II inhibitors that not only exhibit inhibit potency but also are free of side effects. Probing the scaffold diversity of known inhibitors is vital to achieving this goal. A systematic review and discussion on the scaffold diversity of COX inhibitors are still limited. To address this gap, herein we present an overview of chemical structures and inhibitory activity of different scaffolds of known COX-II inhibitors. The insights from this article could be helpful in seeding the development of next-generation COX-II inhibitors.

Synthesis and Biological Evaluation of Arylamide Sulphonate Derivatives as Ectonucleotide Pyrophosphatase/Phosphodiesterase-1 and -3 Inhibitors

Aberrant level of ectonucleotide pyrophosphatase/phosphodiesterase-1 and -3 is linked with numerous disorders, for instance, diabetes, cancer, osteoarthritis, chondrocalcinosis, and allergic reactions. These disorders may be cured or minimized by blocking the activity of ENPP1 and ENPP3 isozymes. In this study, arylamide sulphonates were synthesized, characterized, and evaluated for their capability to affect the activity of isozymes ENPP1 and ENPP3. Among the selective inhibitors of ENPP1, compounds 4f and 4q exhibited sub-micromolar IC₅₀ values of 0.28 ± 0.08 and 0.37 ± 0.03 μM, respectively, followed by 7a, with IC₅₀ equal to 0.81 ± 0.05 μM, whereas out of the selective inhibitors of isozyme ENPP3, 4t and 7d preferably lessened the activity to half of the maximal inhibitory concentration of 0.15 ± 0.04 and 0.16 ± 0.01 μM alternatively. In addition, many structures including 4c, 4g, 4k, 4l, 4n, 4o, 4r, 4s, 7b, 7c, and 7e inhibited the activity of both isozymes to a significant level. Enzyme kinetic study of compound 4j revealed an uncompetitive mode of inhibition of ENPP1 isozyme, while 7e competitively blocked the activity of ENPP3. Cell viability analysis revealed the compound 4o as a cytotoxic agent against MCF7 (human breast cancer cell line) with a percentage inhibition of 63.2 ± 2.51%, whereas compounds 4c, 4d, 4n, and 7d decreased the HeLa cell viability (human cervical cancer cell line) to more than 50%. The tested compounds were non-cytotoxic against HEK293 (a human embryonic kidney cell line). Molecular docking analysis of selected inhibitors of both isozymes produced optimistic interactions with the influential amino acids, such as Leu290, Lys295, Tyr340, Asp376, His380, and Pro323 of ENPP1, whereas residues Asn226, His329, Leu239, Tyr289, Pro272, Tyr320, and Ala205 of ENPP3 crystallographic structure formed interactions with the potent inhibitors.

Expedition of sulfur-containing heterocyclic derivatives as cytotoxic agents in medicinal chemistry: A decade update

This review article proposes a comprehensive report of the design strategies engaged in the development of various sulfur-bearing cytotoxic agents. The outcomes of various studies depict that the sulfur heterocyclic framework is a fundamental structure in diverse synthetic analogs representing a myriad scope of therapeutic activities. A number of five-, six- and seven-membered sulfur-containing heterocyclic scaffolds, such as thiazoles, thiadiazoles, thiazolidinediones, thiophenes, thiopyrans, benzothiazoles, benzothiophenes, thienopyrimidines, simple and modified phenothiazines, and thiazepines have been discussed. The subsequent studies of the derivatives unveiled their cytotoxic effects through multiple mechanisms (viz. inhibition of tyrosine kinases, topoisomerase I and II, tubulin, COX, DNA synthesis, and PI3K/Akt and Raf/MEK/ERK signaling pathways), and several others. Thus, our concise illustration explains the design strategy and anticancer potential of these five- and six-membered sulfur-containing heterocyclic molecules along with a brief outline on seven-membered sulfur heterocycles. The thorough assessment of antiproliferative activities with the reference drug allows a proficient assessment of the structure-activity relationships (SARs) of the diversely synthesized molecules of the series.

Synthesis, biological evaluation, and docking studies of novel pyrrolo[2,3-b]pyridine derivatives as both ectonucleotide pyrophosphatase/phosphodiesterase inhibitors and antiproliferative agents

Ecto-nucleotide pyrophosphatases/phosphodiesterases (NPPs) together with nucleoside triphosphate diphosphohydrolases (NTPDases) and alkaline phosphatases (APs) are nucleotidases located at the surface of the cells. NPP1 and NPP3 are important members of NPP family that are known as druggable targets for a number of disorders such as impaired calcification, type 2 diabetes, and cancer. Sulfonylurea derivatives have been reported as antidiabetic and anticancer agents, therefore, we synthesized and investigated series of sulfonylurea derivatives 1a-m possessing pyrrolo[2,3-b]pyridine core as inhibitors of NPP1 and NPP3 isozymes that are over-expressed in cancer and diabetes. The enzymatic evaluation highlighted compound 1a as selective NPP1 inhibitor, however, 1c was observed as the most potent inhibitor of NPP1 with an IC₅₀ value of 0.80 ± 0.04 μM. Compound 1l was found to be the most potent and moderately selective inhibitor of NPP3 (IC₅₀ = 0.55 ± 0.01 μM). Furthermore, in vitro cytotoxicity assays of compounds 1a-m against MCF-7 and HT-29 cancer cell lines exhibited compound 1c (IC₅₀ = 4.70 ± 0.67 μM), and 1h (IC₅₀ = 1.58 ± 0.20 μM) as the most cytotoxic compounds against MCF-7 and HT-29 cancer cell lines, respectively. Both of the investigated compounds showed high degree of selectivity towards cancer cells than normal cells (WI-38). Molecular docking studies of selective and potent enzyme inhibitors revealed promising mode of interactions with important binding sites residues of both isozymes i.e., Thr256, His380, Lys255, Asn277 residues of NPP1 and His329, Thr205, and Leu239 residues of NPP3. In addition, the most potent antiproliferative agent, compound 1h, doesn't produce hypoglycemia as a side effect when injected to mice. This is an additional merit of the promising compound 1h.

Synthesis, molecular docking and ADME studies of thiazole-thiazolidinedione hybrids as antimicrobial agents

New thiazole-thiazolidinedione hybrids (5a-k) were efficiently synthesized and evaluated for their in-vitro antimicrobial activity against four fungal and bacterial strains. The chemical structures of the compounds were elucidated by FTIR, ¹H NMR, and ¹³C NMR spectral data. Most of the synthesized compounds were sensitive against gram positive, gram negative bacterial and fungal strains. Among the synthesized molecules, compounds 5h, and 5i exhibited promising inhibitory activity against all selected fungal strains and gram positive bacteria namely, Staphylococcus aureus, and Enterococcus faecalis. The molecular docking results predicted that the thiazole-thiazolidinedione derivatives bind to the active site protein ATP-binding pocket from E. coli, S. aureus and C. albicans with good interaction energy scores. Ct-DNA was used to evaluate the binding interactions of the selected compounds by means of absorption spectroscopy. To further characterize the drug-likeness and ADME properties were calculated using the Qikprop, the result of present study suggests that thiazole-thiazolidinedione hybrid could be an interesting approach for the design of new antimicrobial agents.Communicated by Ramaswamy H. Sarma.

Evaluation of sulfonate and sulfamate derivatives possessing benzofuran or benzothiophene nucleus as inhibitors of nucleotide pyrophosphatases/phosphodiesterases and anticancer agents

Ectonucleotidases are a broad family of ectoenzymes that play a crucial role in purinergic cell signaling. Ecto-nucleotide pyrophosphatases/phosphodiesterases (NPPs) belong to this group and are important drug targets. In particular, NPP1 and NPP3 are known to be druggable targets for treatment of impaired calcification disorders (including pathological aortic calcification) and cancer, respectively. In this study, we investigated a series of sulfonate and sulfamate derivatives of benzofuran and benzothiophene as potent and selective inhibitors of NPP1 and NPP3. Compounds 1c, 1g, 1n, and 1s are the most active NPP1 inhibitors (IC₅₀ values in the range 0.12-0.95 µM). Moreover, compounds 1e, 1f, 1j, and 1l are the most potent inhibitors of NPP3 (IC₅₀ ranges from 0.12 to 0.95 µM). Compound 1d, 1f and 1t are highly selective inhibitors of NPP1 over NPP3, whereas compounds 1m and 1s are found to be highly selective towards NPP3 over NPP1. Structure-activity relationship (SAR) study has been discussed in detailed. With the aid of molecular docking studies, a common binding mode of these compounds and suramin (the standard inhibitor) was revealed, where the sulfonate group acts as a cation-binding moiety that comes in close contact with the zinc ion of the active site. Moreover, cytotoxic evaluation against MCF-7 and HT-29 cancer cell lines revealed that compound 1r is the most cytotoxic towards MCF-7 cell line with IC₅₀ value of 0.19 µM. Compound 1r is more potent and selective against cancer cells than normal cells (WI-38) as compared to doxorubicin.

Synthesis, biological evaluation, and docking studies of new raloxifene sulfonate or sulfamate derivatives as inhibitors of nucleotide pyrophosphatase/phosphodiesterase

A new series of raloxifene sulfonate/sulfamate derivatives were designed and synthesized. The target compounds were tested for inhibitory effect against nucleotide pyrophosphatase/phosphodiesterase-1 and -3 (NPP1 and NPP3) enzymes. Furthermore, all the ten target compounds were subjected to cytotoxic studies on various cancer cell lines, and the most potent derivatives were explored for their potency against these cancer cell lines as well as F180 fibroblasts to investigate the selectivity indexes. Compound 1f exerted the highest potency against HT-29 colon cancer cell line (IC₅₀ = 1.4 μM) with 8.43-fold selectivity towards HT-29 than F180 fibroblasts. Compound 1f exerted sub-micromolar IC₅₀ values against NPP1 and NPP3 (IC₅₀ = 0.29 μM and 0.71 μM, respectively). The most potent inhibitors were docked in developed homology model of NPP1 and crystal structure of NPP3. All the docked analogues manifested remarkable interactions within the active pocket of NPP1 and NPP3.

Synthesis, molecular docking and evaluation of novel sulfonyl hydrazones as anticancer agents and COX-2 inhibitors

In trying to develop new anticancer agents, a series of sulfonylhydrazones were synthesized. All synthesized compounds were checked for identity and purity using elemental analysis, TLC and HPLC and were characterized by their melting points, FT-IR and NMR spectral data. All synthesized compounds were evaluated for their cytotoxic activity against prostate cancer (PC3), breast cancer (MCF-7) and L929 mouse fibroblast cell lines. Among them, N'-[(2-chloro-3-methoxyphenyl)methylidene]-4-methylbenzenesulfonohydrazide (3k) showed the most potent anticancer activity against both cancer cells with good selectivity (IC₅₀ = 1.38 μM on PC3 with SI = 432.30 and IC₅₀ = 46.09 μM on MCF-7 with SI = 12.94). Further investigation confirmed that 3k displayed morphological alterations in PC3 and MCF-7 cells and promoted apoptosis through down-regulation of the Bcl-2 and upregulation of Bax expression. Additionally, compound 3k was identified as the most potent COX-2 inhibitor (91% inhibition) beside lower COX-1 inhibition. Molecular docking of the tested compounds represented important binding modes which may be responsible for their anticancer activity via inhibition of the COX-2 enzyme. Overall, the lead compound 3k deserves further development as a potential anticancer agent. Sulfonylhydrazones was synthesized and N'-[(2-chloro-3-methoxyphenyl)methylidene]-4- methylbenzenesulfonohydrazide (3k) was identified as the most potent anticancer agent and COX-2 inhibitor. In addition, this compound docked inside the active site of COX-2 succesfully.

2-(2-Methoxyphenyl)-3-((Piperidin-1-yl)ethyl)thiazolidin-4-One-Loaded Polymeric Nanocapsules: In Vitro Antiglioma Activity and In Vivo Toxicity Evaluation

Among gliomas types, glioblastoma is considered the most malignant and the worst form of primary brain tumor. It is characterized by high infiltration rate and great angiogenic capacity. The presence of an inflammatory microenvironment contributes to chemo/radioresistance, resulting in poor prognosis for patients. Recent data show that thiazolidinones have a wide range of pharmacological properties, including anti-inflammatory and antiglioma activities. Nanocapsules of biodegradable polymers become an alternative to cancer treatment since they provide targeted drug delivery and could overcome blood-brain barrier. Therefore, here we investigated the in vitro antiglioma activity and the potential in vivo toxicity of 2- (2-methoxyphenyl) -3- ((piperidin-1-yl) ethyl) thiazolidin-4-one-loaded polymeric nanocapsules (4L-N). Nanocapsules were prepared and characterized in terms of particle size, polydispersity index, zeta potential, pH, molecule content and encapsulation efficiency. Treatment with 4L-N selectively decreased human U138MG and rat C6 cell lines viability and proliferation, being even more efficient than the free-form molecule (4L). In addition, 4L-N did not promote toxicity to primary astrocytes. We further demonstrated that the treatment with sub-therapeutic dose of 4L-N did not alter weight, neither resulted in mortality, toxicity or peripheral damage to Wistar rats. Finally, 4L as well as 4L-N did not alter makers of oxidative damage, such as TBARS levels and total sulfhydryl content, and did not change antioxidant enzymes SOD and CAT activity in liver and brain of treated rats. Taken together, these data indicate that the nanoencapsulation of 4L has potentiated its antiglioma effect and does not cause in vivo toxicity.

Anti-inflammatory indomethacin analogs endowed with preferential COX-2 inhibitory activity

Aim: The undeniable indomethacin potency has always suffered serious obstacles such as gastric damage. Continuous attempts to develop potent yet safe indomethacin analogs have never ceased. Results: Herein are new indole derivatives 4a–h and 5a–c, which were synthesized via Fisher indole reaction, evaluated for both their in vivo anti-inflammatory activities using rat paw edema method and their in vitro cyclooxygenase inhibitory activities. Then ulcerogenic liability, physicochemical parameters and molecular docking modeling were performed for the most potent ones. Conclusion: Promising results were obtained, where compound 4f was the best anti-inflammatory agent and preferential COX-2/COX-1 inhibitor (90.5% edema inhibition, selective index = 65.71, ulcer index = 7.3), if compared with indomethacin (86.7% edema inhibition, selective index = 0.079, ulcer index = 20.20).

New hydrazide-hydrazones and 1,3-thiazolidin-4-ones with 3-hydroxy-2-naphthoic moiety: Synthesis, in vitro and in vivo studies

In this research we synthesized, identified and evaluated new hydrazide-hydrazones (1-3) and 1,3-thiazolidin-4-one derivatives (4-6) for in vitro and in vivo activity. New hydrazide-hydrazones (1-3) were obtained by the condensation reaction of 3-hydroxy-2-naphthoic acid hydrazide with appropriate aldehydes. Synthesized hydrazide-hydrazones (1-3) were subjected to cyclization reaction with mercaptoacetic acid which afforded with new 1,3-thiazolidin-4-one derivatives (4-6). Among 1,3-thiazolidin-4-one derivatives tested (4-6), compound 6 exhibited highest and most selective cytotoxicity towards human renal adenocarcinoma cells (769-P) and it did not affect the growth of normal cells (H9c2, GMK). Whereas its hydrazide-hydrazone (compound 3) showed significant antiproliferative activity against both tested human cancer cell lines: renal adenocarcinoma (769-P) and hepatocellular carcinoma (HepG2), however with less selectivity. The in vivo studies focused on the antinociceptive activity of newly synthesized 1,3-thiazolidin-4-one derivatives (4-6). The preliminary screening of novel compounds showed that 1,3-thiazolidin-4-one derivatives (4-6) are safe and not toxic against CNS of mice. Among tested derivatives one compound (6) displayed significant analgesic activity.

Novel diphenylthiazole derivatives with multi-target mechanism: Synthesis, docking study, anticancer and anti-inflammatory activities

Over the last few decades, a growing body of studies addressed the anticancer activity of NSAIDs, particularly selective COX-2 inhibitors. However, their exact molecular mechanism is still unclear and is not fully investigated. In this regard, a novel series of compounds bearing a COXs privilege scaffold, diphenyl thiazole, was synthesized and evaluated for their anticancer activity against a panel of cancer cell lines. The most active compounds 10b, 14a,b, 16a, 17a,b and 18b were evaluated in vitro for COX-1/COX-2 inhibitory activity. These compounds were suggested to exert their anticancer activity through a multi-target mechanism based on their structural features. Thus, compounds 10b and 17b with the least IC₅₀ values in MTT assay were tested against three known anticancer targets; EGFR, BRAF and tubulin. Compounds 10b and 17b showed remarkable activity against EGFR with IC₅₀ values of 0.4 and 0.2μM, respectively and good activity against BRAF with IC₅₀ values of 1.3 and 1.7μM, respectively. In contrast, they showed weak activity in tubulin polymerization assay. The in vivo anti-inflammatory potential was assessed and interestingly, compound 17b was the most potent compound. Together, this study offers some important insights into the correlation between COXs inhibition and cancer treatment. Additionally, the results demonstrated the promising activity of these compounds with a multi-target mechanism as good candidates for further development into potential anticancer agents.

Design, synthesis and biological evaluation of new pyrrolidine carboxamide analogues as potential chemotherapeutic agents for hepatocellular carcinoma

The successful targeting of different malignancies by OSU-2S, encouraged us to design and synthesize a novel series of pyrrolidine aryl carboxamide derivatives. In this context, we found that, the amide nature and tether length were found to be key determinant elements for the anticancer activity of these new and rigid analogues of OSU-2S. The most effective analogues induced apoptosis in cancer cells by a similar mechanism to that of OSU-2S, possibly via the activation of PKCδ in addition to their ability to induce cell cycle arrest and inhibition of cancer cell migration. Compound 10m, possesses anticancer potency comparable to that of OSU-2S when tested against cancer cell lines under study, and was found to be safer on normal cells. Furthermore, compound 10m, was found to be about 2-folds more potent than the anticancer drug Sorafenib in hepatocellular carcinoma (HCC). The newly developed compounds represent a therapeutically promising approach for the treatment of HCC.

Synthetic 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones exhibit selective in vitro antitumoral activity and inhibit cancer cell growth in a preclinical model of glioblastoma multiforme

Glioblastoma multiforme (GBM) is the worst form of primary brain tumor, which has a high rate of infiltration and resistance to radiation and chemotherapy, resulting in poor prognosis for patients. Recent studies show that thiazolidinones have a wide range of pharmacological properties including antimicrobial, anti-inflammatory, anti-oxidant and anti-tumor. Here, we investigate the effect antiglioma in vitro of a panel of sixteen synthetic 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones where 13 of these decreased the viability of glioma cells 30-65% (100 μM) compared with controls. The most promising compounds such as 4d, 4l, 4m and 4p promoted glioma reduction of viability greater than 50%, were further tested at lower concentrations (12.5, 25, 50 and 100 μM). Also, the data showed that the compounds 4d, 4l, 4m and 4p induced cell death primarily through necrosis and late apoptosis mechanisms. Interestingly, none of these 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones were cytotoxic for primary astrocytes, which were used as a non-transformed cell model, indicating selectivity. Our results also show that the treatment with sub-therapeutic doses of 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones (4d, 4l and 4p) reduced in vivo glioma growth as well as malignant characteristics of implanted tumors such as intratumoral hemorrhage and peripheral pseudopalisading. Importantly, 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones treatment did not induce mortality or peripheral damage to animals. Finally, 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones also changed the nitric oxide metabolism which may be associated with reduced growth and malignity characteristics of gliomas. These data indicates for the first time the therapeutic potential of synthetic 2-aryl-3-((piperidin-1-yl)ethyl)thiazolidin-4-ones to GBM treatment.

Design, synthesis and analgesic/anti-inflammatory evaluation of novel diarylthiazole and diarylimidazole derivatives towards selective COX-1 inhibitors with better gastric profile

The inhibition of gastric cyclooxygenase 1 (COX-1) enzyme was believed to be the major cause of non-steroidal anti-inflammatory drugs (NSAIDs)-induced gastric ulcer. Recent studies disproved this belief and showed that the gastric tissues vulnerability is not solely connected to COX-1 inhibition. This work aimed at exploring and rationalizing the differential analgesic and anti-inflammatory activities of novel selective COX-1 inhibitors with improved gastric profile. Two novel series of 4,5-diarylthiazole and diarylimidazole were designed, synthesized in analogy to selective COX-1 inhibitors (mofezolac and FR122047) which lack gastric damaging effects. The new compounds were evaluated in vitro for their COXs inhibitory activity and in vivo for their anti-inflammatory and analgesic potentials. Four compounds; diphenylthiazole glycine derivatives (15a, 15b) and diphenylimidazolo acetic acid derivatives (19a, 19b), which possess carboxylic acid group exhibited significant activity and selectivity against COX-1 over COX-2. Of these compounds, (4,5-bis(4-methoxyphenyl)thiazol-2-yl)glycine 15b was the most potent compound against COX-1 with an inhibitory half maximal concentration (IC₅₀) of 0.32μM and a selectivity index (COX-2 IC₅₀/COX-1 IC₅₀) of 28.84. Furthermore, an ulcerogenicity study was performed where the tested compounds demonstrated a significant gastric tolerance. Interestingly, the most selective COX-1 inhibitor showed higher analgesic activity in vivo as expected compared to their moderate anti-inflammatory activity. This study underscores the need for further design and development of novel analgesic agents with low tendency to cause gastric damage based on improving their COX-1 affinity and selectivity profile.

Synthesis, biological evaluation, docking study and ulcerogenicity profiling of some novel quinoline-2-carboxamides as dual COXs/LOX inhibitors endowed with anti-inflammatory activity

A series of novel quinoline-2-carboxamides 15-28 was synthesized and evaluated in vitro as dual COXs/LOX inhibitors. Compounds 19 and 27 exhibited the highest potency and selectivity for COX-2 inhibitory activity (IC₅₀ = 1.21 and 1.13 μM, respectively; selectivity index (COX-1/COX-2) = 6.52 and 7.61, respectively) in comparison to the reference drug celecoxib (COX-2 IC₅₀ = 0.88 μM; selectivity index (COX-1/COX-2) = 8.31). The anti-inflammatory activity of the newly synthesized compounds was further assessed in vivo using carrageenan induced paw edema assay. Interestingly, the in vitro results of COXs inhibitory assay were consistent with that of the in vivo assay where compounds 19 and 27 showed the highest anti-inflammatory activity with edema inhibition percentages of 59.38% and 65.03%, respectively compared to celecoxib (71.21%) after 5 h. Moreover, it was found that compounds 19 and 27 have a superior gastric safety profile comparable to indomethacin. The molecular docking study of compounds 19 and 27 into COX-2 active site suggested that these hits assumed binding pattern and interactions similar to that of bromocelecoxib (S-58) as a cocrystallized ligand explaining their remarkable COX-2 inhibitory activity and selectivity. Taken together, these results indicated that these derivatives are good leads for subsequent development into potential anti-inflammatory agents with least gastric damage.

Structure-activity relationship (SAR) study and design strategies of nitrogen-containing heterocyclic moieties for their anticancer activities

The present review article offers a detailed account of the design strategies employed for the synthesis of nitrogen-containing anticancer agents. The results of different studies describe the N-heterocyclic ring system is a core structure in many synthetic compounds exhibiting a broad range of biological activities. Benzimidazole, benzothiazole, indole, acridine, oxadiazole, imidazole, isoxazole, pyrazole, triazoles, quinolines and quinazolines including others drugs containing pyridazine, pyridine and pyrimidines are covered. The following studies of these compounds suggested that these compounds showed their antitumor activities through multiple mechanisms including inhibiting protein kinase (CDK, MK-2, PLK1, kinesin-like protein Eg5 and IKK), topoisomerase I and II, microtubule inhibition, and many others. Our concise representation exploits the design and anticancer potency of these compounds. The direct comparison of anticancer activities with the standard enables a systematic analysis of the structure-activity relationship among the series.

Synthesis and Biological Evaluation of Novel Benzothiazole Derivatives as Potential Anticonvulsant Agents

New benztriazoles with a mercapto-triazole and other heterocycle substituents were synthesized and evaluated for their anticonvulsant activity and neurotoxicity by using the maximal electroshock (MES), subcutaneous pentylenetetrazole (scPTZ), and rotarod neurotoxicity (TOX) tests. Among the compounds studied, compound 2-((1H-1,2,4-triazol-3-yl)thio)-N-(6-((3-fluorobenzyl)oxy)benzo[d]thiazol-2-yl)acetamide (5i) and 2-((1H-1,2,4-triazol-3-yl)thio)-N-(6-((4-fluorobenzyl)oxy)benzo[d] thiazol-2-yl)acetmide (5j) were the most potent, with an ED₅₀ value of 50.8 mg/kg and 54.8 mg/kg in the MES test and 76.0 mg/kg and 52.8 mg/kg in the scPTZ seizures test, respectively. They also showed lower neurotoxicity and, therefore a higher protective index. In particular, compound 5j showed high protective index (PI) values of 8.96 in the MES test and 9.30 in the scPTZ test, which were better than those of the standard drugs used as positive controls in this study.

Novel Thymohydroquinone Derivatives as Potential Anticancer Agents: Design, Synthesis, and Biological Screening

The safety and efficacy of naturally occurring anticancer agents and their derivatives such as thymoquinone (TQ) and thymohydroquinone (THQ) have gained a rapidly growing interest. In an attempt to develop novel anticancer agents with superior activity, TQ was allowed to react with hydrazine hydrate, producing hydrazino thymohydroquinone 3. This new intermediate was subsequently reacted with various isocyanates, isothiocyanates, and acyl halides, affording three series of semicarbazone, semithiocarbazone, and acyl hydrazone derivatives, respectively. Subsequently, the anticancer activity of all the newly synthesised compounds against a panel of cancer cell lines was evaluated. Initial screening of the ability of the test compounds to inhibit cancer cell viability using the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that compounds 5d and 6 exerted better activity against breast cancer than TQ, with half-maximal inhibitory concentration (IC50) values of 9.6 and 10.0 μM, respectively. MTT results were confirmed by the ability of these compounds to elicit apoptotic cell death through the activation of caspase 3/7 enzymes. Together, the present work provided a novel class of THQ-based derivatives with potent anticancer and apoptosis properties, thereby warranting further optimisation of these derivatives as novel members in cancer treatment protocols.

Design, synthesis, and anti-inflammatory evaluation of novel diphenylthiazole-thiazolidinone hybrids

A series of diphenylthiazole-thiazolidinone hybrids was synthesized and evaluated in vitro and in vivo as anti-inflammatory/analgesic agents. The inhibition of cyclooxygenase (COX) enzymes was suggested as a molecular mechanism for the hybrids to exert their anti-inflammatory action. Of these compounds, 13b, 14, and 15b showed the most potent COX inhibitory activity with IC50 values between 2.03 and 12.27 µM, but with different selectivity profiles. All compounds were further evaluated in vivo for their anti-inflammatory/analgesic activities using three animal models. Interestingly, the results of the COX assay were in agreement with those of in vivo assays where the most potent COX inhibitors, 13b, 14, and 15b, exhibited the highest anti-inflammatory/analgesic activities compared to diclofenac. On the contrary, compounds 11 and 12 were the least potent ligands in vitro and in vivo as well.