Synthesis and SAR of thiazolidinedione derivatives as 15-PGDH inhibitors

Discovery of highly potent and selective influenza virus neuraminidase inhibitors targeting 150-cavity

Encouraged by our earlier discovery of N1-selective inhibitors, the 150-cavity of influenza virus neuraminidases (NAs) could be further exploited to yield more potent oseltamivir derivatives. Herein, we report the design, synthesis and biological evaluation of a series of novel oseltamivir derivatives via the structural modifications at C₅-NH₂ of oseltamivir targeting 150-cavity. Among them, compound 5c bearing 4-(3-methoxybenzyloxy)benzyl group exhibited the most potent activity, which was lower or modestly improved activities than oseltamivir carboxylate (OSC) against N1 (H1N1), N1 (H5N1) and N1 (H5N1-H274Y). Specifically, there was 30-fold loss of activity against the wild-type strain H1N1. However, 5c displayed 4.85-fold more potent activity than OSC against H5N1-H274Y NA. Also, 5c demonstrated low cytotoxicity in vitro and no acute toxicity in mice. Molecular docking studies provided insights into the high potency of 5c against N1 and N1-H274Y mutant NAs. Besides, the in silico prediction of physicochemical properties and CYP enzymatic inhibitory ability of representative compounds were conducted to evaluate their drug-like properties.

Synthesis and Hypoglycemic and Anti-inflammatory Activity Screening of Novel Substituted 5-[Morpholino(Phenyl)Methyl]-Thiazolidine-2,4-Diones and Their Molecular Docking Studies

Objectives

The aim was the synthesis of novel substituted 5-[morpholino(phenyl)methyl]-thiazolidine-2,4-diones and screening for their in vivo hypoglycemic activity and in vitro anti-inflammatory activity, as well as molecular docking studies to find out active potential lead molecules.

Materials and Methods

Substituted aromatic aldehydes, thiazolidine-2,4-dione, and morpholine on Mannich reaction gave the title compounds. They were characterized by physical and spectral methods. In vivo hypoglycemic activity was examined in alloxan induced Wistar albino rats by tail tipping method. In vitro anti-inflammatory activity was tested by human red blood cell (HRBC) membrane stabilization and protein denaturation. Using AutoDock, molecular docking studies were carried out to find out the best fit ligands.

Results

Series of substituted 5-[morpholino(phenyl)methyl]-thiazolidine-2,4-diones were synthesized and chemically they were confirmed by spectral techniques. Acute toxic studies of in vivo hypoglycemic activity results revealed that compounds 4c, 4h, and 4n exhibited good activity at 35 mg/kg body weight. Chronic toxic study results indicated that compounds 4h and 4n exhibited good activity at 70 mg/kg body weight. Anti-inflammatory activity results indicated the highest inhibition was shown by compounds 4k and 4f at 500 μg/mL in HRBC membrane stabilization. In protein denaturation, the highest inhibition was shown by compound 4k at 500 μg/mL. In molecular docking studies, compounds 4h and 4n exhibited higher binding affinity at PPARγ receptor protein and compound 4k exhibited higher binding affinity at COX-1 and COX-2 actives sites.

Conclusion

Microwave irradiation produced high yield in short reaction times. The presence of electron releasing groups at the para position of the phenyl ring may give the ability to produce hypoglycemic activity and the presence of electron withdrawing groups at the para position of the phenyl ring causes anti-inflammatory activity. The results showed that some compounds exhibited good hypoglycemic and anti-inflammatory activities. Compounds 4h and 4n exhibited higher binding affinity at PPARγ receptor protein and compound 4k exhibited higher binding affinity at COX isoenzymes' active sites in molecular docking studies.

Synthesis of Phenyl- and Pyridyl-substituted Benzyloxybenzaldehydes by Suzuki-Miyaura Coupling Reactions

Background:

Aryl-methoxybenzaldehydes substituted in various positions may serve as valuable starting materials for the synthesis of biologically active compounds.

Methods:

Biaryl-methoxybenzaldehydes and pyridyl-aryl-methoxybenzaldehydes were synthesized by the Suzuki-Miyaura cross-coupling reactions as intermediates of potential drug substances. Three different catalytic approaches were compared. The classical Suzuki method utilising tetrakis(triphenylphosphine)palladium and sodium ethoxide, the protocol applying palladium acetate and tri(o-tolyl)phosphine, and the method using tetrakis(triphenylphosphine)palladium and cesium carbonate, were studied.

Results:

The selected boronic acids were the classical phenylboronic acid, as well as 4-pyridineand 3-pyridineboronic acids. 26 New biaryl-methoxybenzaldehydes or pyridyl-phenylmethoxybenzaldehydes have been synthesized, which may be intermediates for pharmaceutically active compounds.

Conclusion:

The method of Anderson et al. was preferred, because it provides satisfactory results in all cases.

Investigation of 15-hydroxyprostaglandin dehydrogenase catalytic reaction mechanism by molecular dynamics simulations

15-hydroxyprostaglandin dehydrogenase (15-PGDH) is a prostaglandin metabolizing enzyme that oxidizes the hydroxyl group at carbon 15 (C15). The aim of the present work is to propose the main amino acids that catalyze the reaction through studying the intermolecular interaction between the ligand and the enzyme inside the active site using molecular dynamics simulation (MD). Therefore, MD simulations for two 15-PGDH systems bound with a substrate (PGE₂) or an inhibitor (compound 4) were performed to investigate the importance of ligand interaction on the behavior of amino acids in the active site. Findings from this work proposed the amino acids: Tyr151, Gln148 & Asn95 to act as a catalytic triad for the reaction as hydrogen bond interactions, dihedral rotation analysis and MM-GBSA free energy calculations revealed.

Discovery of Benzamidine- and 1-Aminoisoquinoline-Based Human MAS-Related G-Protein-Coupled Receptor X1 (MRGPRX1) Agonists

Mas-related G-protein-coupled receptor X1 (MRGPRX1) is a human sensory neuron-specific receptor and has been actively investigated as a therapeutic target for the treatment of pain. By use of two HTS screening hit compounds, 4-(4-(benzyloxy)-3-methoxybenzylamino)benzimidamide (5a) and 4-(2-(butylsulfonamido)-4-methylphenoxy)benzimidamide (11a), as molecular templates, a series of human MRGPRX1 agonists were synthesized and evaluated for their agonist activity using HEK293 cells stably transfected with human MrgprX1. Conversion of the benzamidine moiety into a 1-aminoisoquinoline moiety carried out in the later stage of structural optimization led to the discovery of a highly potent MRGPRX1 agonist, N-(2-(1-aminoisoquinolin-6-yloxy)-4-methylphenyl)-2-methoxybenzenesulfonamide (16), not only devoid of positively charged amidinium group but also with superior selectivity over opioid receptors. In mice, compound 16 displayed favorable distribution to the spinal cord, the presumed site of action for the MRGPRX1-mediated analgesic effects.

Design, synthesis, biological evaluation and molecular docking studies of novel 3-substituted-5-[(indol-3-yl)methylene]-thiazolidine-2,4-dione derivatives

Various thiazolidine-2,4-dione derivatives 3a-l possessing indole moiety were designed, synthesized using appropriate conventional heating as well as microwave irradiation methods. All the synthesized compounds were characterized physically and spectrally. The compounds were evaluated for in vitro antibacterial activity, in vitro antioxidant activity and in vivo hypoglycemic activity in relation to the standard drugs. Most of the new compounds exhibited moderate activity and some showed considerable activity. Molecular docking studies were carried out using AutoDock software and revealed that compound 3b has significant binding interaction with PPARγ receptor compared with the standard ligand Rosiglitazone.

Effect of thiazolidinedione phenylacetate derivatives on wound-healing activity

The aim of this work was to evaluate the synthesis and structure-activity relationship of 4-((2,4-dioxothiazolidin-5-ylidene)methyl)phenyl 2-phenylacetate derivatives as potential wound-healing agents. The IC₅₀ values of the lead compounds ranged from 0.01 to 0.05 µM. These compounds also increased the levels of extracellular prostaglandin E₂ (PGE₂) in A549 cells. Among the synthesized compounds, compounds 66, 67, 69, and 86 increased PGE₂ levels 3- to 4-fold of those achieved with the negative control. Introduction of a halogen at the intermediate phenyl ring, compounds 66, 67, 69, and 86 resulted in higher IC₅₀ values, which indicated lower cytotoxicity than that observed upon the introduction of other substituents at the same position. In particular, cells exposed to compound 69 showed significantly improved wound healing, and the wound closure rate achieved was approximately 3.2-fold higher than that of the control. Therefore, compound 69 can be used for tissue regeneration and treatment of diverse diseases caused by PGE₂ deficiency. Overall, our findings suggested that compound 69 might be a novel candidate for skin wound therapy.

5-Ene-4-thiazolidinones - An efficient tool in medicinal chemistry

The presented review is an attempt to summarize a huge volume of data on 5-ene-4-thiazolidinones being a widely studied class of small molecules used in modern organic and medicinal chemistry. The manuscript covers approaches to the synthesis of 5-ene-4-thiazolidinone derivatives: modification of the C5 position of the basic core; synthesis of the target compounds in the one-pot or multistage reactions or transformation of other related heterocycles. The most prominent pharmacological profiles of 5-ene derivatives of different 4-thiazolidinone subtypes belonging to hit-, lead-compounds, drug-candidates and drugs as well as the most studied targets have been discussed. Currently target compounds (especially 5-en-rhodanines) are assigned as frequent hitters or pan-assay interference compounds (PAINS) within high-throughput screening campaigns. Nevertheless, the crucial impact of the presence/nature of C5 substituent (namely 5-ene) on the pharmacological effects of 5-ene-4-thiazolidinones was confirmed by the numerous listed findings from the original articles. The main directions for active 5-ene-4-thiazolidinones optimization have been shown: i) complication of the fragment in the C5 position; ii) introduction of the substituents in the N3 position (especially fragments with carboxylic group or its derivatives); iii) annealing in complex heterocyclic systems; iv) combination with other pharmacologically attractive fragments within hybrid pharmacophore approach. Moreover, the utilization of 5-ene-4-thiazolidinones in the synthesis of complex compounds with potent pharmacological application is described. The chemical transformations cover mainly the reactions which involve the exocyclic double bond in C5 position of the main core and correspond to the abovementioned direction of the 5-ene-4-thiazolidinone modification.

Differential Sex Response to Aspirin in Decreasing Aneurysm Rupture in Humans and Mice

We previously found that aspirin decreases the risk of cerebral aneurysm rupture in humans. We aim to assess whether a sex differential exists in the response of human cerebral aneurysms to aspirin and confirm these observations in a mouse model of cerebral aneurysm. A nested case-control analysis from the International Study of Unruptured Intracranial Aneurysms was performed to assess whether a sex differential exists in the response of human cerebral aneurysms to aspirin. A series of experiments were subsequently performed in a mouse model of cerebral aneurysms. Aneurysms were induced with hypertension and elastase injection into mice basal cisterns. We found that aspirin decreased the risk of aneurysm rupture more significantly in men than in women in the International Study of Unruptured Intracranial Aneurysms. In mice, aspirin and cyclooxygenase-2 inhibitor did not affect cerebral aneurysm formation but significantly decreased the incidence of rupture. The incidence of rupture was significantly lower in male versus female mice on aspirin. Gene expression analysis from cerebral arteries showed higher 15-hydroxyprostaglandin dehydrogenase levels in male mice. The rate of cerebral aneurysm rupture was similar in male mice receiving aspirin and 15-hydroxyprostaglandin dehydrogenase inhibitor compared with females receiving aspirin and 15-hydroxyprostaglandin dehydrogenase agonist, signaling a reversal of the sex-differential response to aspirin. Aspirin decreases aneurysm rupture in human and mice, in part through cyclooxygenase-2 pathways. Evidence from animal and human studies suggests a consistent differential effect by sex. 15-Hydroxyprostaglandin dehydrogenase activation in females reduces the incidence of rupture and eliminates the sex-differential response to aspirin.

Effect of 15-hydroxyprostaglandin dehydrogenase inhibitor on wound healing

PGE2 is an important mediator of wound healing. It is degraded and inactivated by 15-hydroxyprostaglandin dehydrogenase (15-PGDH). Various growth factors, type IV collagen, TIMP-2 and PGE2 are important mediators of inflammation involving wound healing. Overproduction of TGF-β and suppression of PGE2 are found in excessive wound scarring. If we make the condition downregulating growth factors and upregulating PGE2, the wound will have a positive effect which results in little scar formation after healing. TD88 is a 15-PGDH inhibitor based on thiazolinedione structure. We evaluated the effect of TD88 on wound healing. In 10 guinea pigs (4 control and 6 experimental groups), we made four 1cm diameter-sized circular skin defects on each back. TD88 and vehicle were applicated on the wound twice a day for 4 days in the experimental and control groups, respectively. Tissue samples were harvested for qPCR and histomorphometric analyses on the 2nd and 4th day after treatment. Histomorphometric analysis showed significant reepithelization in the experimental group. qPCR analysis showed significant decrease of PDGF, CTGF and TIMP-2, but significant increase of type IV collagen in the experimental group. Taken together TD88 could be a good effector on wound healing, especially in the aspects of prevention of scarring.

Wound healing effects of new 15-hydroxyprostaglandin dehydrogenase inhibitors

Previously, we reported that the antidiabetic drug ciglitazone and its analogs were potent inhibitors of 15-hydroxyprostaglandin dehydrogenase (15-PGDH). In continuing attempts to develop highly potent 15-PGDH inhibitors, a series of thiazolidinedione analogs were synthesized and tested. Compound 17 exhibited IC50 of 45 nM. This compound also significantly increased levels of prostaglandin E2 (PGE2) in A549 cells by approximately eight-fold that in the control. Much experimental data suggests that PGE2 plays a role in the prevention of excessive scarring. However, it has a very short half-life in blood, its oxidization to 15-ketoprostaglandins is catalyzed by 15-PGDH. Therefore, 15-PGDH inhibitors may have utility for the therapeutic management of diseases requiring elevated PGE2 levels. Scratch wounds were analyzed in confluent monolayers of HaCaT cells. Cells exposed to compound 17 showed significantly improved wound healing with respect to a control.

Repurposing the antihistamine terfenadine for antimicrobial activity against Staphylococcus aureus

Staphylococcus aureus is a rapidly growing health threat in the U.S., with resistance to several commonly prescribed treatments. A high-throughput screen identified the antihistamine terfenadine to possess, previously unreported, antimicrobial activity against S. aureus and other Gram-positive bacteria. In an effort to repurpose this drug, structure-activity relationship studies yielded 84 terfenadine-based analogues with several modifications providing increased activity versus S. aureus and other bacterial pathogens, including Mycobacterium tuberculosis. Mechanism of action studies revealed these compounds to exert their antibacterial effects, at least in part, through inhibition of the bacterial type II topoisomerases. This scaffold suffers from hERG liabilities which were not remedied through this round of optimization; however, given the overall improvement in activity of the set, terfenadine-based analogues provide a novel structural class of antimicrobial compounds with potential for further characterization as part of the continuing process to meet the current need for new antibiotics.

Control of the intracellular levels of prostaglandin E₂ through inhibition of the 15-hydroxyprostaglandin dehydrogenase for wound healing

Excessive scar formation is an aberrant form of wound healing and is an indication of an exaggerated function of fibroblasts and excess accumulation of extracellular matrix during wound healing. Much experimental data suggests that prostaglandin E₂ (PGE₂) plays a role in the prevention of excessive scarring. However, it has a very short half-live in blood, its oxidization to 15-ketoprostaglandins is catalyzed by 15-hydroxyprostaglandin dehydrogenase (15-PGDH). Previously, we reported that 15-PGDH inhibitors significantly increased PGE₂ levels in A549 cells. In our continuing attempts to develop highly potent 15-PGDH inhibitors, we newly synthesized various thiazolidine-2,4-dione derivatives. Compound 27, 28, 29, and 30 demonstrated IC₅₀ values of 0.048, 0.020, 0.038 and 0.048 μM, respectively. They also increased levels of PGE₂ in A549 cells. Especially, compound 28 significantly increased level of PGE₂ at 260 pg/mL, which was approximately fivefold higher than that of control. Scratch wounds were analyzed in confluent monolayers of HaCaT cells. Cells exposed to compound 28 showed significantly improved wound healing with respect to control.

Recent pharmacological developments on rhodanines and 2,4-thiazolidinediones

Thiazolidines are five-member heterocyclic having sulfur, nitrogen, and oxygen atoms in their ring structure and exhibiting potent as well as wide range of pharmacological activities. In this minireview, recent updates on synthesis and pharmacological evaluations of molecules based on 2,4-thiazolidine and rhodanine are discussed.

Synthesis, characterization and biological evaluation of some novel 2,4-thiazolidinediones as potential cytotoxic, antimicrobial and antihyperglycemic agents

A series of some novel 2,4-thiazolidinediones (TZDs) (2a-x) have been synthesized and characterized by FTIR, (1)H NMR, (13)C NMR and LC mass spectral analysis. All the synthesized compounds were evaluated for their cytotoxicity, antimicrobial and in vivo antihyperglycemic activities. Among the tested compounds for cytotoxicity using Brine Shrimp Lethality assay, compound 2t ((Z)-5-(4-((E)-3-oxo-3-(thiophen-2-yl)prop-1-enyl)benzylidene)-1,3-thiazolidine-2,4-dione) exhibited significant inhibitory activity at ED(50) value 4.00±0.25 μg/mL and this level of activity was comparable to that of the reference drug podophyllotoxin with ED(50) value 3.61±0.17 μg/mL. Antimicrobial activity was screened using agar well diffusion assay method against selected Gram-positive, Gram-negative and fungal strains and the activity expressed as the minimum inhibitory concentration (MIC) in μg/mL. From the results of antimicrobial activity compound 2s ((Z)-5-(4-((E)-3-(3,5-bis(benzyloxy)phenyl)-3-oxoprop-1-enyl)benzylidene)-1,3-thiazolidine-2,4-dione) was found to be the most active against all the tested strains of microorganisms with MIC value 16 μg/mL. In vivo antihyperglycemic effect of twenty four TZDs (2a-x) at different doses 10, 30 and 50mg/kg b.w (oral) were assessed using percentage reduction of plasma glucose (PG) levels in streptozotocin-induced type II diabetic rat models. From the results, the novel compound 2x ((Z)-5-(4-((E)-3-(9H-fluoren-2-yl)-3-oxoprop-1-enyl)benzylidene)-1,3-thiazolidine-2,4-dione) exhibited considerably potent blood glucose lowering activity than that of the standard drug rosiglitazone and it could be a remarkable starting point to evaluate structure-activity relationships and to develop new lead molecules with potential cytotoxicity, antimicrobial and antihyperglycemic activities. In addition molecular docking studies were carried out against PPARγ molecular target using Molegro Virtual Docker v 4.0 to accomplish preliminary confirmation of the observed in vivo antihyperglycemic activity.

Algicidal activity of thiazolidinedione derivatives against harmful algal blooming species

Thiazolidinedione (TD) derivatives exhibit algicidal activity against harmful algal blooming species such as Chattonella marina, Heterosigma akashiwo, and Cochlodinium polykrikoides, as reported previously. In this study, the efficacies and selectivities of TD derivatives were tested by analyzing the structure-activity relationships of various TD derivatives. To investigate structure-activity relationships for growth inhibition of harmful algae, we added a methylene group between the cyclohexyl ring and oxygen of 5-(3-chloro-4-hydroxybenzylidene)-TD, which decreased the inhibitory potency of compound 17. Interestingly, another addition of a methylene group significantly increased the inhibitory potency against C. polykrikoides. The addition of 1 μM compound 17 resulted in the cell rupture of harmful algae after less than 10 h incubation at 20 °C. Compound 17 was applied to both harmful and non-harmful algae and showed a drastic reduction in the efficiency of photosystem II, resulting in reduced photosynthetic oxygen evolution. Compound 17 at a 5 μM concentration destroyed all of the harmful algae, while algicidal activity against non-harmful algae did not exceed 30% of the control within the concentration range tested. In contrast, a herbicide, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, tested at a 5 μM concentration, exhibited 40-70% algicidal activity relative to that of the control against both harmful and non-harmful algae. Compound 17 is a promising lead compound for the development of algicides to control harmful algal blooming species.