Thiazole derivatives as inhibitors of cyclooxygenases in vitro and in vivo

In vitro activity, ultrastructural analysis and in silico pharmacokinetic properties (ADMET) of thiazole compounds against adult worms of Schistosoma mansoni

The present work aimed to carry out in vitro biological assays of thiazole compounds against adult worms of Schistosoma mansoni, as well as the in silico determination of pharmacokinetic parameters to predict the oral bioavailability of these compounds. In addition to presenting moderate to low cytotoxicity against mammalian cells, thiazole compounds are not considered hemolytic. All compounds were initially tested at concentrations ranging from 200 to 6.25 μM against adult worms of S. mansoni parasites. The results showed the best activity of PBT2 and PBT5 at a concentration of 200 μM, which caused 100% mortality after 3 h of incubation. While at 6 h of exposure, 100% mortality was observed at the concentration of 100 µM. Subsequent studies with these same compounds allowed classifying PBT5, PBT2, PBT6 and PBT3 compounds, which were considered active and PBT1 and PBT4 compounds, which were considered inactive. In the ultrastructural analysis the compounds PBT2 and PBT5 (200 µM) promoted integumentary changes with exposure of the muscles, formation of integumentary blisters, integuments with abnormal morphology and destruction of tubercles and spicules. Therefore, the compounds PBT2 and PBT5 are promising antiparasitics against S. mansoni.

New Thiazole Carboxamide Derivatives as COX Inhibitors: Design, Synthesis, Anticancer Screening, In Silico Molecular Docking, and ADME Profile Studies

The goal of this work was to create and test a new series of thiazole carboxamide derivatives for their cyclooxygenase (COX) suppressor and anticancer effects. The compounds were characterized using 1H, 13C NMR, and HRMS spectrum analysis, and their selectivity toward COX-1 and COX-2 was assessed using an in vitro COX inhibition assay kit. Cytotoxicity was assessed using an MTS assay against a panel of cancer and normal cell lines. The docking studies were aided by the Prime MM-GBSA method for estimating binding affinities. The density functional theory (DFT) analysis was performed to assess compound chemical reactivity, which was calculated by computing the border orbital energy of both HOMO and LUMO orbitals, as well as the HOMO-LUMO energy gap. For ADME-T analysis, the QiKProp module was employed. Furthermore, using human X-ray crystal structures, molecular docking studies were carried out to discover the probable binding patterns of these drugs within both COX-1 and COX-2 isozymes. The results demonstrated that the most effective compound against the COX-1 enzyme was 2b with an IC50 of 0.239 μM. It also showed potent activity against COX-2 with an IC50 value of 0.191 μM and a selectivity ratio of 1.251. The highest selectivity ratio was 2.766 for compound 2a against COX-2 with an IC50 dose of 0.958 μM relating to the celecoxib ratio of 23.8 and its IC50 against COX-2 of 0.002 μM. Compound 2j also showed good selectivity toward COX-2 (1.507) with an IC50 value of 0.957 μM. All compounds showed negligible cytotoxic activity against the evaluated normal cell lines, and the IC50 values were more than 300 μM, except for compound 2b, whose IC50 values were 203.71 ± 1.89 and 116.96 ± 2.05 μM against LX-2 and Hek293t cell lines, respectively. Moreover, compound 2b showed moderate anticancer activity against COLO205 and B16F1 cancer cell lines with IC50 values of 30.79 and 74.15 μM, respectively.

Fluorinated Benzofuran and Dihydrobenzofuran as Anti-Inflammatory and Potential Anticancer Agents

Benzofuran and 2,3-dihydrobenzofuran scaffolds are heterocycles of high value in medicinal chemistry and drug synthesis. Targeting inflammation in cancer associated with chronic inflammation is a promising therapy. In the present study, we investigated the anti-inflammatory effects of fluorinated benzofuran and dihydrobenzofuran derivatives in macrophages and in the air pouch model of inflammation, as well as their anticancer effects in the human colorectal adenocarcinoma cell line HCT116. Six of the nine compounds suppressed lipopolysaccharide-stimulated inflammation by inhibiting the expression of cyclooxygenase-2 and nitric oxide synthase 2 and decreased the secretion of the tested inflammatory mediators. Their IC₅₀ values ranged from 1.2 to 9.04 µM for interleukin-6; from 1.5 to 19.3 µM for Chemokine (C-C) Ligand 2; from 2.4 to 5.2 µM for nitric oxide; and from 1.1 to 20.5 µM for prostaglandin E₂. Three novel synthesized benzofuran compounds significantly inhibited cyclooxygenase activity. Most of these compounds showed anti-inflammatory effects in the zymosan-induced air pouch model. Because inflammation may lead to tumorigenesis, we tested the effects of these compounds on the proliferation and apoptosis of HCT116. Two compounds with difluorine, bromine, and ester or carboxylic acid groups inhibited the proliferation by approximately 70%. Inhibition of the expression of the antiapoptotic protein Bcl-2 and concentration-dependent cleavage of PARP-1, as well as DNA fragmentation by approximately 80%, were described. Analysis of the structure-activity relationship suggested that the biological effects of benzofuran derivatives are enhanced in the presence of fluorine, bromine, hydroxyl, and/or carboxyl groups. In conclusion, the designed fluorinated benzofuran and dihydrobenzofuran derivatives are efficient anti-inflammatory agents, with a promising anticancer effect and a combinatory treatment in inflammation and tumorigenesis in cancer microenvironments.

Design, synthesis, molecular docking studies and biological evaluation of thiazole carboxamide derivatives as COX inhibitors

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been the most commonly used class of medications worldwide for the last three decades.

OBJECTIVES

This study aimed to design and synthesize a novel series of methoxyphenyl thiazole carboxamide derivatives and evaluate their cyclooxygenase (COX) suppressant and cytotoxic properties.

METHODS

The synthesized compounds were characterized using ¹H, ¹³C-NMR, IR, and HRMS spectrum analysis and were evaluated for their selectivity towards COX-1 and COX-2 using an in vitro COX inhibition assay kit. Besides, their cytotoxicity was evaluated using the Sulforhodamine B (SRB) assay. Moreover, molecular docking studies were conducted to identify the possible binding patterns of these compounds within both COX-1 and COX-2 isozymes, utilizing human X-ray crystal structures. The density functional theory (DFT) analysis was used to evaluate compound chemical reactivity, which was determined by calculating the frontier orbital energy of both HOMO and LUMO orbitals, as well as the HOMO-LUMO energy gap. Finally, the QiKProp module was used for ADME-T analysis.

RESULTS

The results revealed that all synthesized molecules have potent inhibitory activities against COX enzymes. The percentage of inhibitory activities at 5 µM concentration against the COX2 enzyme was in the range of 53.9-81.5%, while the percentage against the COX-1 enzyme was 14.7-74.8%. That means almost all of our compounds have selective inhibition activities against the COX-2 enzyme, and the most selective compound was 2f, with selectivity ratio (SR) value of 3.67 at 5 µM concentration, which has a bulky group of trimethoxy on the phenyl ring that could not bind well with the COX-1 enzyme. Compound 2h was the most potent, with an inhibitory activity percentage at 5 µM concentration of 81.5 and 58.2% against COX-2 and COX-1, respectively. The cytotoxicity of these compounds was evaluated against three cancer cell lines: Huh7, MCF-7, and HCT116, and negligible or very weak activities were observed for all of these compounds except compound 2f, which showed moderate activities with IC₅₀ values of 17.47 and 14.57 µM against Huh7 and HCT116 cancer cell lines, respectively. Analysis of the molecular docking suggests 2d, 2e, 2f, and 2i molecules were bound to COX-2 isozyme favorably over COX-1 enzyme, and their interaction behaviors within COX-1 and COX-2 isozymes were comparable to celecoxib, as an ideal selective COX-2 drug, which explained their high potency and COX-2 selectivity. The molecular docking scores and expected affinity using the MM-GBSA approach were consistent with the recorded biological activity. The calculated global reactivity descriptors, such as HOMO and LUMO energies and the HOMO-LUMO gaps, confirmed the key structural features required to achieve favorable binding interactions and thus improve affinity. The in silico ADME-T studies asserted the druggability of molecules and have the potential to become lead molecules in the drug discovery process.

CONCLUSION

In general, the series of the synthesized compounds had a strong effect on both enzymes (COX-1 and COX-2) and the trimethoxy compound 2f was more selective than the other compounds.

Synthesis of 4-(4-chlorophenyl)thiazole compounds: in silico and in vitro evaluations as leishmanicidal and trypanocidal agents

Neglected tropical diseases are a diverse group of communicable pathologies that mainly prevail in tropical and subtropical regions. Thus, the objective of this work was to evaluate the biological potential of eight 4-(4-chlorophenyl)thiazole compounds. Tests were carried out in silico to evaluate the pharmacokinetic properties, the antioxidant, cytotoxic activities in animal cells and antiparasitic activities were evaluated against the different forms of Leishmania amazonensis and Trypanosoma cruzi in vitro. The in silico study showed that the evaluated compounds showed good oral availability. In a preliminary in vitro study, the compounds showed moderate to low antioxidant activity. Cytotoxicity assays show that the compounds showed moderate to low toxicity. In relation to leishmanicidal activity, the compounds presented IC50 values that ranged from 19.86 to 200 µM for the promastigote form, while for the amastigote forms, IC50 ranged from 101 to more than 200 µM. The compounds showed better results against the forms of T. cruzi with IC50 ranging from 1.67 to 100 µM for the trypomastigote form and 1.96 to values greater than 200 µM for the amastigote form. This study showed that thiazole compounds can be used as future antiparasitic agents.

2-amino thiazole derivatives as inhibitors of some metabolic enzymes: An In Vitro and In Silico study

The thiazole derivatives are desirable compounds in the evaluation of their biological activities such as antiprotozoal antibacterial, antifungal, antituberculosis. Considering the medical application potential of 2-amino thiazole compounds, we aimed to determine the effects of 2-amino thiazole derivatives on the activities of carbonic anhydrase I-II isoenzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Among the chemicals we used in our study, 2-Amino-4-(4-chlorophenyl)thiazole compound exhibited the best inhibition against hCA I with K_i of 0.008±0.001 μM. The 2-Amino-4-(4-bromophenyl)thiazole compound exhibited the best inhibition against hCA II, AChE and BChE with K_i of 0.124±0.017 μM, 0.129±0.030 μM and 0.083±0.041 μM, respectively. Molecular docking analysis showed that compound 2-Amino-4-(5,6,7,8-tetrahydro-2-naphthyl)thiazole had the highest inhibitory potency against hCA I, hCA II, AChE, BChE with the estimated binding energy of -6.75 , -7.61, -7.86, -7.96 kcal/mol, respectively. This article is protected by copyright. All rights reserved.

"Azole" as privileged heterocycle for targeting the inducible cyclooxygenase enzyme

An over-expression of COX-2 isoenzyme belonging to the Cyclooxygenase Enzyme Family triggers the overproduction of pro-inflammatory prostaglandins that instigate the development of chronic inflammation and related disorders. Hence, the rationally designed drugs for mitigating over-activity of COX-2 isoenzyme play a regulatory role toward the alleviation of the progression of these disorders. However, a selective COX-2 inhibition chemotherapy prompts several side effects that necessitate the identification of novel molecular scaffolds for deliberating state-of-the-art drug designing strategies. The heterocyclic "azole" scaffold, being polar and hydrophilic, possesses remarkable physicochemical advantages for designing physiologically active molecules capable of interacting with a wide range of biological components, including enzymes, peptides, and metabolites. The substituted derivatives of azole nuclei enable a comprehensive SAR analysis for the appraisal of bioactive profile of the deliberated molecules for obtaining the rationally designed compounds with prominent activities. The comprehensive SAR analysis readily prompted the identification of Y-shaped molecules and the eminence of bulkier group for COX-2 selective inhibition. This review presents an epigrammatic collation of the pharmacophore-profile of the chemotherapeutics based on azole motif for a selective targeting of the COX-2 isoenzyme.

gem-Difluorobisarylic derivatives: design, synthesis and anti-inflammatory effect

Introduction

New fluorinated diaryl ethers and bisarylic ketones were designed and evaluated for their anti-inflammatory effects in primary macrophages.

Methods

The synthesis of the designed molecules started from easily accessible and versatile gem-difluoro propargylic derivatives. The desired aromatic systems were obtained using Diels-Alder/aromatization sequences and this was followed by Pd-catalyzed coupling reactions and, when required, final functionalization steps. Both direct inhibitory effects on cyclooxygenase-1 or -2 activities, protein expression of cyclooxygenase-2 and nitric oxide synthase-II and the production of prostaglandin E₂, the pro-inflammatory nitric oxide and interleukin-6 were evaluated in primary murine bone marrow-derived macrophages in response to lipopolysaccharide. Docking of the designed molecules in cyclooxygenase-1 or -2 was performed.

Results

Only fluorinated compounds exerted anti-inflammatory activities by lowering the secretion of interleukin-6, nitric oxide, and prostaglandin E₂, and decreasing the protein expression of inducible nitric oxide synthase and cyclooxygenase-2 in mouse primary macrophages exposed to lipopolysaccharide, as well as cyclooxygenase activity for some inhibitors with different efficiencies depending on the R-groups. Docking observation suggested an inhibitory role of cyclooxygenase-1 or -2 for compounds A3, A4 and A5 in addition to their capacity to inhibit nitrite, interleukin-6, and nitric oxide synthase-II and cyclooxygenase-2 expression.

Conclusion

The new fluorinated diaryl ethers and bisarylic ketones have anti-inflammatory effects in macrophages. These fluorinated compounds have improved potential anti-inflammatory properties due to the fluorine residues in the bioactive molecules.

Heme oxygenase-1-Dependent anti-inflammatory effects of atorvastatin in zymosan-injected subcutaneous air pouch in mice

Statins exert pleiotropic and beneficial anti-inflammatory and antioxidant effects. We have previously reported that macrophages treated with statins increased the expression of heme oxygenase-1 (HO-1), an inducible anti-inflammatory and cytoprotective stress protein, responsible for the degradation of heme. In the present study, we investigated the effects of atorvastatin on inflammation in mice and analyzed its mechanism of action in vivo. Air pouches were established in 8 week-old female C57BL/6J mice. Atorvastatin (5 mg/kg, i.p.) and/or tin protoporphyrin IX (SnPPIX), a heme oxygenase inhibitor (12 mg/kg, i.p.), were administered for 10 days. Zymosan, a cell wall component of Saccharomyces cerevisiae, was injected in the air pouch to trigger inflammation. Cell number and levels of inflammatory markers were determined in exudates collected from the pouch 24 hours post zymosan injection by flow cytometry, ELISA and quantitative PCR. Analysis of the mice treated with atorvastatin alone displayed increased expression of HO-1, arginase-1, C-type lectin domain containing 7A, and mannose receptor C-type 1 in the cells of the exudate of the air pouch. Flow cytometry analysis revealed an increase in monocyte/macrophage cells expressing HO-1 and in leukocytes expressing MRC-1 in response to atorvastatin. Mice treated with atorvastatin showed a significant reduction in cell influx in response to zymosan, and in the expression of proinflammatory cytokines and chemokines such as interleukin-1α, monocyte chemoattractant protein-1 and prostaglandin E₂. Co-treatment of mice with atorvastatin and tin protoporphyrin IX (SnPPIX), an inhibitor of heme oxygenase, reversed the inhibitory effect of statin on cell influx and proinflammatory markers, suggesting a protective role of HO-1. Flow cytometry analysis of air pouch cell contents revealed prevalence of neutrophils and to a lesser extent of monocytes/macrophages with no significant effect of atorvastatin treatment on the modification of their relative proportion. These findings identify HO-1 as a target for the therapeutic actions of atorvastatin and highlight its potential role as an in vivo anti-inflammatory agent.

Thiazoles and Thiazolidinones as COX/LOX Inhibitors

Inflammation is a natural process that is connected to various conditions and disorders such as arthritis, psoriasis, cancer, infections, asthma, etc. Based on the fact that cyclooxygenase isoenzymes (COX-1, COX-2) are responsible for the production of prostaglandins that play an important role in inflammation, traditional treatment approaches include administration of non-steroidal anti-inflammatory drugs (NSAIDs), which act as selective or non-selective COX inhibitors. Almost all of them present a number of unwanted, often serious, side effects as a consequence of interference with the arachidonic acid cascade. In search for new drugs to avoid side effects, while maintaining high potency over inflammation, scientists turned their interest to the synthesis of dual COX/LOX inhibitors, which could provide numerous therapeutic advantages in terms of anti-inflammatory activity, improved gastric protection and safer cardiovascular profile compared to conventional NSAIDs. Τhiazole and thiazolidinone moieties can be found in numerous biologically active compounds of natural origin, as well as synthetic molecules that possess a wide range of pharmacological activities. This review focuses on the biological activity of several thiazole and thiazolidinone derivatives as COX-1/COX-2 and LOX inhibitors.

N-Adamantyl-4-Methylthiazol-2-Amine Attenuates Glutamate-Induced Oxidative Stress and Inflammation in the Brain

In this study, we explored the possible mechanisms underlying the neuroprotective and anti-oxidative effects of N-adamantyl-4-methylthiazol-2-amine (KHG26693) against in vivo glutamate-induced toxicity in the rat cerebral cortex. Our results showed that pretreatment with KHG26693 significantly attenuated glutamate-induced elevation of lipid peroxidation, tumor necrosis factor-α, interferon gamma, IFN-γ, interleukin-1β, nitric oxide, reactive oxygen species, NADPH oxidase, caspase-3, calpain activity, and Bax. Furthermore, KHG26693 pretreatment attenuated key antioxidant parameters such as levels of superoxide dismutase, catalase, glutathione, and glutathione reductase. KHG26693 also attenuated the protein levels of inducible nitric oxide synthase, neuronal nitric oxide synthase, nuclear factor erythroid 2-related factor 2, heme oxygenase-1, and glutamate cysteine ligase catalytic subunit caused by glutamate toxicity. Finally, KHG26693 mitigated glutamate-induced changes in mitochondrial ATP level and cytochrome oxidase c. Thus, KHG26693 functions as neuroprotective and anti-oxidative agent against glutamate-induced toxicity through its antioxidant and anti-inflammatory activities in rat brain at least in part.

First isolation of glutinol and a bioactive fraction with good anti-inflammatory activity from n-hexane fraction of Peltophorum africanum leaf

OBJECTIVE

To investigate the anti-inflammatory activity of different fractions and glutinol (isolated compound), using nitric oxide synthase and cyclooxygenase (COX) inhibition as an indication of anti-inflammatory activity.

METHODS

Anti-inflammatory activity was evaluated using an in vitro assay determining the inhibition of the activity of pro-inflammatory enzyme model. Cyclooxygenases and inducible nitric oxide synthase are crucial enzymes involved in the pathogenesis of many chronic inflammatory conditions.

RESULTS

Sub-fraction F3.3 that was derived from n-hexane fraction of PA leaves significantly inhibited (P = 0.01) the catalytic activity of COX-2 (IC₅₀ = 0.67 μg/mL) better than isolated compound, glutinol (IC₅₀ = 1.22 μg/mL), compound 2 (CP2) (IC₅₀ = 1.71 μg/mL) and sub-fraction F3.3.0 (IC₅₀ = 1.30 μg/mL). A similar trend was observed in investigation of the inhibition of nitric oxide synthesis in RAW 264.7 cells by F3.3, glutinol, CP2 and F3.3.0. Inducible COX-2 and inducible nitric oxide synthase are among potent signalling enzymes that exacerbate inflammation.

CONCLUSIONS

Bioactive sub-fractions (F3.3 and F3.3.0) derived from the n-hexane fraction of PA had good anti-inflammatory activity, and the isolated compound, and glutinol may be useful as a template for the development of new anti-inflammatory drugs.

Neuroprotective effects of N-adamantyl-4-methylthiazol-2-amine against amyloid β-induced oxidative stress in mouse hippocampus

We previously reported that N-adamantyl-4-methylthiazol-2-amine (KHG26693) suppresses amyloid beta (Aβ)-induced neuronal oxidative damage in cortical neurons. Here we investigated the mechanism and antioxidative function of KHG26693 in the hippocampus of Aβ-treated mice. KHG26693 significantly attenuated Aβ-induced TNF-α and IL-1β enhancements. KHG26693 decreased Aβ-mediated malondialdehyde formation, protein oxidation, and reactive oxygen species by decreasing the iNOS level. KHG26693 suppressed Aβ-induced oxidative stress through a mechanism involving glutathione peroxidase, catalase, and GSH attenuation. Aβ-induced MMP-2, cPLA2, and pcPLA2 expressions were almost completely attenuated by KHG26693 treatment, suggesting that Aβ-induced oxidative stress reduction by KHG26693 is, at least partly, caused by the downregulation of MMP-2 and cPLA2 activation. Compared with Aβ treatment, KHG26693 treatment upregulated Nrf2 and HO-1 expressions, suggesting that KHG26693 protects the brain from Aβ-induced oxidative damage, likely by maintaining redox balance through Nrf2/HO-1 pathway regulation. KHG26693 significantly attenuated Aβ-induced oxidative stress in the hippocampus of Aβ-treated mice.