Fenamates and ibuprofen as foundational components in the synthesis of innovative, targeted COX-2 anti-inflammatory drugs, undergoing thorough biopharmacological assessments and in-silico computational studies.

Cyclooxygenase-2 plays a vital role in inflammation by catalyzing arachidonic acid conversion toward prostaglandins, making it a prime therapeutic objective. Selective COX-2 inhibitors represent significant progress in anti-inflammatory therapy, offering improved efficacy and fewer side effects. This study describes the synthesis of novel anti-inflammatory compounds from established pharmaceutically marketed agents like fenamates III-V and ibuprofen VI. Through rigorous in vitro testing, compounds 7b-c, and 12a-b demonstrated substantial in vitro selective inhibition, with IC50 values of 0.07 to 0.09 µM, indicating potent pharmacological activity. In vivo assessment, particularly focusing on compound 7c, revealed significant anti-inflammatory effects. Markedly, it demonstrated the highest inhibition of paw thickness (58.62 %) at the 5-hr mark compared to the carrageenan group, indicating its potency in mitigating inflammation. Furthermore, it exhibited a rapid onset of action, with a 54.88 % inhibition observed at the 1-hr mark. Subsequent comprehensive evaluations encompassing analgesic efficacy, histological characteristics, and toxicological properties indicated that compound 7c did not induce gastric ulcers, in contrast to the ulcerogenic tendency associated with mefenamic acid. Moreover, compound 7c underwent additional investigations through in silico methodologies such as molecular modelling, field alignment, and density functional theory. These analyses underscored the therapeutic potential and safety profile of this novel compound, warranting further exploration and development in the realm of pharmaceutical research.

Binding of Monovalent and Bivalent Ligands by Transthyretin Causes Different Short- and Long-Distance Conformational Changes.

The wild type protein, transthyretin (TTR), and over 120 genetic TTR variants are amyloidogenic and cause, respectively, sporadic and hereditary systemic TTR amyloidosis. The homotetrameric TTR contains two identical thyroxine binding pockets, occupation of which by specific ligands can inhibit TTR amyloidogenesis in vitro. Ligand binding stabilizes the tetramer, inhibiting its proteolytic cleavage and its dissociation. Here, we show with solution-state NMR that ligand binding induces long-distance conformational changes in the TTR that have not previously been detected by X-ray crystallography, consistently with the inhibition of the cleavage of the DE loop. The NMR findings, coupled with surface plasmon resonance measurements, have identified dynamic exchange processes underlying the negative cooperativity of binding of "monovalent" ligand tafamidis. In contrast, mds84, our prototypic "bivalent" ligand, which is a more potent stabilizer of TTR in vitro that occupies both thyroxine pockets and the intramolecular channel between them, has greater structural effects.

Redox-cycling and intercalating properties of novel mixed copper(II) complexes with non-steroidal anti-inflammatory drugs tolfenamic, mefenamic and flufenamic acids and phenanthroline functionality: Structure, SOD-mimetic activity, interaction with albumin, DNA damage study and anticancer activity.

Copper(II) complexes containing non-steroidal anti-inflammatory drugs (NSAIDs) have been the subject of many research papers and reviews. Here we report the synthesis, spectroscopic study and biological activity of novel mixed copper(II) complexes with NSAIDs: tolfenamic (tolf), mefenamic (mef) and flufenamic (fluf) acids and phenanthroline (phen): [Cu(tolf-O,O')2(phen)] (1), [Cu(mef-O,O')2(phen)] (2), [Cu(fluf-O,O')2(phen)] (3). Complexes were characterized by X-ray analysis and EPR spectroscopy. Complexes 1-3 are monomeric, six-coordinate and crystallize in a monoclinic space group. Interaction of Cu(II) complexes with DNA was studied by means of absorption titrations, viscosity measurements and gel electrophoresis. The relative ability of the complexes to cleave DNA even in the absence of hydrogen peroxide is in the order 3 > 2 > 1. Application of the reactive oxygen species (ROS) scavengers, L-histidine, DMSO and SOD confirmed that singlet oxygen, hydroxyl radicals (Fenton reaction) and superoxide radical were formed, respectively. Thus, in addition to mechanism of intercalation, redox-cycling mechanism which in turn lead to the formation of ROS contribute to DNA damage. Cu(II) complexes exhibit excellent SOD-mimetic activity in the order 3~1 > 2. The fluorescence spectroscopy revealed that albumin may act as a targeted drug delivery vehicle for Cu(II) complexes (K~106). The anticancer activities of complexes 1-3 were investigated using an MTS assay (reduction of the tetrazolium compound) against three cancer cell lines (HT-29 human colon adenocarcinoma, HeLa and T-47D breast cancer cells) and mesenchymal stromal cells (MSC). The most promising compound, from the viewpoint of its NSAID biological activity is 3, due to the presence of the three fluorine atoms participating in the formation of weak hydrogen-bonds at the DNA surface.

Synthesis, analgesic, anti-inflammatory and anti-ulcerogenic activities of certain novel Schiff's bases as fenamate isosteres.

A series of certain novel Schiff bases as fenamate isosteres (VI:a-k) were synthesized to locate analgesic, anti-inflammatory agent with minimal ulcerogenic potential. The structures of the newly synthesized compounds were elucidated on the basis of their elemental analysis as well as IR, and NMR and mass spectroscopic data. All the compounds were evaluated for their anti-inflammatory activity by carrageenan induced paw oedema method. The compounds possessing good anti-inflammatory activity were further tested for analgesic, ulcerogenic, lipid peroxidation potentials and liver toxicity. Compounds (VI-c), (VI-f), (VI-h) and (VI-i) showed the best anti-inflammatory and significant analgesic activities at doses comparable to that of the standard drug Indomethacin. However, compounds (VI-c) and (VI-f) could be considered the most potent anti-inflammatory and analgesic molecules with maximum reduction in gastro-intestinal ulceration with no hepatocyte necrosis or liver degeneration.

Effect of non-steroidal anti-inflammatory drugs and new fenamate analogues on TRPC4 and TRPC5 channels.

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used anti-inflammatory therapeutic agents, among which the fenamate analogues play important roles in regulating intracellular Ca²âº transient and ion channels. However, the effect of NSAIDs on TRPC4 and TRPC5 is still unknown. To understand the structure-activity of fenamate analogues on TRPC channels, we have synthesized a series of fenamate analogues and investigated their effects on TRPC4 and TRPC5 channels. Human TRPC4 and TRPC5 cDNAs in tetracycline-regulated vectors were transfected into HEK293 T-REx cells. The whole cell current and Ca²âº movement were recorded by patch clamp and calcium imaging, respectively. Flufenamic acid (FFA), mefenamic acid (MFA), niflumic acid (NFA) and diclofenac sodium (DFS) showed inhibition on TRPC4 and TRPC5 channels in a concentration-dependent manner. The potency was FFA>MFA>NFA>DFS. Modification of 2-phenylamino ring by substitution of the trifluoromethyl group in FFA with F, CH3, OCH3, OCH2CH3, COOH, and NO2 led to the changes in their channel blocking activity. However, 2-(2'-methoxy-5'-methylphenyl)aminobenzoic acid stimulated TRPC4 and TRPC5 channels. Selective COX1-3 inhibitors (aspirin, celecoxib, acetaminophen, and indomethacin) had no effect on the channels. Longer perfusion (> 5 min) with FFA (100 µM) and MFA (100 µM) caused a potentiation of TRPC4 and TRPC5 currents after their initial blocking effects that appeared to be partially mediated by the mitochondrial Ca²âº release. Our results suggest that fenamate analogues are direct modulators of TRPC4 and TRPC5 channels. The substitution pattern and conformation of the 2-phenylamino ring could alter their blocking activity, which is important for understanding fenamate pharmacology and new drug development targeting the TRPC channels.

Development of potent and selective inhibitors of aldo-keto reductase 1C3 (type 5 17ß-hydroxysteroid dehydrogenase) based on N-phenyl-aminobenzoates and their structure-activity relationships.

Aldo-keto reductase 1C3 (AKR1C3; type 5 17ß-hydroxysteroid dehydrogenase) is overexpressed in castration resistant prostate cancer (CRPC) and is implicated in the intratumoral biosynthesis of testosterone and 5α-dihydrotestosterone. Selective AKR1C3 inhibitors are required because compounds should not inhibit the highly related AKR1C1 and AKR1C2 isoforms which are involved in the inactivation of 5α-dihydrotestosterone. NSAIDs, N-phenylanthranilates in particular, are potent but nonselective AKR1C3 inhibitors. Using flufenamic acid, 2-{[3-(trifluoromethyl)phenyl]amino}benzoic acid, as lead compound, five classes of structural analogues were synthesized and evaluated for AKR1C3 inhibitory potency and selectivity. Structure-activity relationship (SAR) studies revealed that a meta-carboxylic acid group relative to the amine conferred pronounced AKR1C3 selectivity without loss of potency, while electron withdrawing groups on the phenylamino B-ring were optimal for AKR1C3 inhibition. Lead compounds did not inhibit COX-1 or COX-2 but blocked the AKR1C3 mediated production of testosterone in LNCaP-AKR1C3 cells. These compounds offer promising leads toward new therapeutics for CRPC.

Trapping of palindromic ligands within native transthyretin prevents amyloid formation.

Transthyretin (TTR) amyloidosis is a fatal disease for which new therapeutic approaches are urgently needed. We have designed two palindromic ligands, 2,2'-(4,4'-(heptane-1,7-diylbis(oxy))bis(3,5-dichloro-4,1-phenylene)) bis(azanediyl)dibenzoic acid (mds84) and 2,2'-(4,4'-(undecane-1,11-diylbis(oxy))bis(3,5-dichloro-4,1-phenylene)) bis(azanediyl)dibenzoic acid (4ajm15), that are rapidly bound by native wild-type TTR in whole serum and even more avidly by amyloidogenic TTR variants. One to one stoichiometry, demonstrable in solution and by MS, was confirmed by X-ray crystallographic analysis showing simultaneous occupation of both T4 binding sites in each tetrameric TTR molecule by the pair of ligand head groups. Ligand binding by native TTR was irreversible under physiological conditions, and it stabilized the tetrameric assembly and inhibited amyloidogenic aggregation more potently than other known ligands. These superstabilizers are orally bioavailable and exhibit low inhibitory activity against cyclooxygenase (COX). They offer a promising platform for development of drugs to treat and prevent TTR amyloidosis.

The synthesis and structure-activity relationship of substituted N-phenyl anthranilic acid analogs as amyloid aggregation inhibitors.

It is believed that beta-amyloid aggregation is an important event in the development of Alzheimer's disease. In the course of our studies to identify beta-amyloid aggregation inhibitors, a series of N-phenyl anthranilic acid analogs were synthesized and studied for beta-amyloid inhibition activity. The synthesis, structure-activity relationship, and in vivo activity of these analogs are discussed.

Synthesis, analgesic and anti inflammatory activities of some new fenamate analogues.

A series of fenamate quinazolinyl analogues, viz acids 6a-d, esters 6e-h, carbohydrazides 7a-d, arylidenes 8a-d, oxadiazol-2-ones 13a-d and oxadiazol-2-thiones 14a-d, have been prepared and screened for their analgesic (acetic acid-induced writhing), anti-inflammatory (carrageenan-induced rat paw edema) activities as well as their ulcerogenic effects. All the final compounds except 7a-d and 8a-d showed good dual activities. Compounds 6a, 6b, 6e, 6f, 13a and 14a showed activities comparable to that of mefenamic acid (CAS 61-68-7) in the acetic acid-induced writhing model as well as in the carrageenan-induced rat paw edema test at a dose level of 100 mg/ kg.Compounds 6a and 6b were highly ulcerogenic, while compounds 6e, 6f, 13a and 14a exhibited the lowest ulcerogenic effects.