In vitro aldose reductase inhibitory activity of 5-benzyl-2,4-thiazolidinediones

Biological effects of bis-hydrazone compounds bearing isovanillin moiety on the aldose reductase

Aldose reductase (ALR2), one of the metabolically important enzymes, catalyzes the formation of sorbitol from glucose in the polyol pathway. ALR2 inhibition is required to prevent diabetic complications. In the present study, the novel bis-hydrazone compounds bearing isovanillin moiety (GY1-12) were synthesized, and various chromatographic methods were applied to purify the ALR2 enzyme. Afterward, the inhibitory effect of the synthesized compounds on the ALR2 was screened in vitro. All the novel bis-hydrazones demonstrated activity in nanomolar levels as AR inhibitors with IC₅₀ and K_I values in the range of 12.55-35.04 nM, and 13.38-88.21 nM, respectively. Compounds GY-11, GY-7, and GY-5 against ALR2 were identified as the highly potent inhibitors, respectively, and were superior to the standard drug, epalrestat. Moreover, a comprehensive ligand-receptor interactions prediction was performed using ADME-Tox, Glide XP, and MM-GBSA modules of Schrödinger Small-Molecule Drug Discovery Suite to elucidate the novel bis-hydrazone derivatives, potential binding modes versus the ALR2. As a result, these compounds with ALR2 inhibitory effects may be potential alternative agents that can be used to treat or prevent diabetic complications.

Non-carboxylic acid inhibitors of aldose reductase based on N-substituted thiazolidinedione derivatives

In search of dually active PPAR-modulators/aldose reductase (ALR2) inhibitors, 16 benzylidene thiazolidinedione derivatives, previously reported as partial PPARγ agonists, together with additional 18 structural congeners, were studied for aldose reductase inhibitory activity. While no compounds had dual property, our efforts led to the identification of promising inhibitors of ALR2. Eight compounds (11, 15-16, 20-24, 30) from the library of 33 compounds were identified as potent and selective inhibitors of ALR2. Compound 21 was the most effective and selective inhibitor with an IC50 value of 0.95 ± 0.11 and 13.52 ± 0.81 μM against ALR2 and aldehyde reductase (ALR1) enzymes, respectively. Molecular docking and dynamics studies were performed to understand inhibitor-enzyme interactions at the molecular level that determine the potency and selectivity. Compound 21 was further subjected to in silico and in vitro studies to evaluate the pharmacokinetic profile. Being less acidic (pKa = 9.8), the compound might have a superior plasma membrane permeability and reach the cytosolic ALR2. This fact together with excellent drug-likeness criteria points to improved bioavailability compared to the clinically used compound Epalrestat. The designed compounds represent a novel group of non-carboxylate inhibitors of aldose reductase with an improved physicochemical profile.

Design and development of novel thiazole-sulfonamide derivatives as a protective agent against diabetic cataract in Wistar rats via inhibition of aldose reductase

In recent years, ALR2 (aldose reductase) inhibitors have attracted attention for their effective ability to reduce the progression of diabetes-associated cataracts. Therefore, in the present article, we intended to develop novel thiazole-sulfonamide hybrids as a potent inhibitor of ALR2. These molecules significantly inhibited the ALR2 level in the rat lenses homogenate, where the most potent compound 7b showed activity comparable to sorbinil as standard. In Wistar rats, compound 7b improved the insulin level and body weight of the experimental animal together with a reduction in the glucose output. Compound 7b showed a significant reduction in the expression of ALR2 in rat lenses in western blot analysis.

Non-acidic bifunctional benzothiazole-based thiazolidinones with antimicrobial and aldose reductase inhibitory activity as a promising therapeutic strategy for sepsis

Sepsis is a life-threatening disease that affects millions of people worldwide. Microbial infections that lead to sepsis syndrome are associated with an increased production of inflammatory molecules. Aldose reductase has recently emerged as a molecular target that is involved in various inflammatory diseases, including sepsis. Herein, a series of previously synthesized benzothiazole-based thiazolidinones that exhibited strong antibacterial and antifungal activities has been evaluated for inhibition efficacy against aldose reductase and selectivity toward aldehyde reductase under in vitro conditions. The most promising inhibitor 5 was characterized with IC₅₀ value of 3.99 μM and a moderate selectivity. Molecular docking simulations revealed the binding mode of compounds at the active site of human aldose reductase. Moreover, owning to the absence of an acidic pharmacophore, good membrane permeation of the novel aldose reductase inhibitors was predicted. Excellent “drug-likeness” was assessed for most of the compounds by applying the criteria of Lipinski’s “rule of five”.

Thiazolidinediones: An In-Depth Study of Their Synthesis and Application to Medicinal Chemistry in the Treatment of Diabetes Mellitus

2,4-Thiazolidinedione (TZD) is a privileged and highly utilised scaffold for the development of pharmaceutically active compounds. This sulfur-containing heterocycle is a versatile pharmacophore that confers a diverse range of pharmacological activities. TZD has been shown to exhibit biological action towards a vast range of targets interesting to medicinal chemists. In this review, we attempt to provide insight into both the historical conventional and the use of novel methodologies to synthesise the TZD core framework. Further to this, synthetic procedures utilised to substitute the TZD molecule at the activated methylene C5 and N3 position are reviewed. Finally, research into developing clinical agents, which act as modulators of peroxisome proliferator-activated receptors gamma (PPARγ), protein tyrosine phosphatase 1B (PTP1B) and aldose reductase 2 (ALR2), are discussed. These are the three most targeted receptors for the treatment of diabetes mellitus (DM).

A convenient approach to synthesize substituted 5-Arylidene-3-m-tolyl thiazolidine-2, 4-diones by using morpholine as a catalyst and its theoretical study

Thiazolidinediones are very important and used as a drug for the treatment of type 2 diabetes. Here, we report a convenient approach to synthesis 3-m-tolyl-5-arylidene-2,4-thiazolidinediones (TZDs) derivatives 7a-e in two steps with moderate to good yield using morpholine as a catalyst. All the structures were confirmed by their spectral IR, ¹H NMR and ¹³C NMR data. The anti-diabatic activity of all synthesized molecules is evaluated by docking with peroxisome proliferator-activated receptor-γ (PPARγ). Preliminary flexible docking studies reveals that our compounds 7a, 7d and 7e showed better binding affinity with the protein and could be a potential candidate for the treatment of type 2 diabetes in near future.

Design, synthesis, in vitro and in silico investigation of aldose reductase inhibitory effects of new thiazole-based compounds

Aldose reductase (AR) catalyzes the NADPH-dependent reduction of glucose to sorbitol in the polyol pathway, which plays an important role in the development of diabetic complications including cataract, retinopathy, nephropathy, and neuropathy. AR has been considered as an important target to heal these long-term diabetic complications and for this reason the development of new AR inhibitors is an important approach in modern medicinal chemistry. In the current study, new 4-aryl-2-[2-((3,4-dihydro-2H-1,5-benzodioxepine-7-yl)methylene)hydrazinyl]thiazole derivatives (1-12) were synthesized and screened for their inhibitory effects on AR which was purified by diverse chromatographic methods with a yield of 1.40% and a specific activity of 2.00 EU/mg. All compounds were determined as promising AR inhibitors with the K_i values in the range of 0.018 ± 0.005 μM-3.746 ± 1.321 μM compared to the quercetin (K_i = 7.025 ± 1.780 μM). In particular, 4-(4-cyanophenyl)-2-[2-((3,4-dihydro-2H-1,5-benzodioxepin-7-yl)methylene)hydrazinyl]thiazole (3) was detected as the most potential AR inhibitor in this series with the K_i value of 0.018 ± 0.005 µM and the compound showed competitive AR inhibition. The cytotoxic effects of compounds 1-12 were investigated on L929 mouse fibroblast (healthy) cells using MTT assay and all these compounds were defined as non-cytotoxic agents against L929 cells. Molecular docking studies, which were employed to determine the affinity of compounds 1-12 into the active site of AR, highlighted that the thiazole scaffold of all these compounds presented π-π stacking interactions with Trp20 and Phe122. According to both in vitro and in silico assays, these potential AR inhibitors may have great importance in the prevention of diabetic microvascular conditions.

Substituted 2-thioxothiazolidin-4-one derivatives showed protective effects against diabetic cataract via inhibition of aldose reductase

In an effort to develop a new class of potent aldose reductase inhibitors against diabetic cataracts, a series of novel 2-thioxothiazolidine-4-one derivatives was synthesized in excellent yields via a facile synthetic route. These compounds were tested against aldehyde (ALR1) and aldose reductase (ALR2) enzymes, where they showed considerable inhibitory activity. Among the tested derivatives, compound 6e showed selective and excellent inhibition of ALR2 over ALR1. The experimental diabetes was induced by the intraperitoneal administration of streptozotocin in male Wistar rats. Compound 6e showed positive modulation of body weight, blood glucose, and blood insulin levels in diabetic rats. Compound 6e also showed ALR2 inhibition as evidenced by Western blot analysis in lens homogenates of Wistar rats having cataract. The docking study of 6e was also performed inside the active site of ALR2 to enumerate the key contacts for inhibitory activity.

A Combinatorial Virtual Screening Approach Driving the Synthesis of 2,4-Thiazolidinedione-Based Molecules as New Dual mPGES-1/5-LO Inhibitors

Dual inhibition of microsomal prostaglandin E₂ synthase-1 (mPGES-1) and 5-lipoxygenase (5-LO), two key enzymes involved in pro-inflammatory eicosanoid biosynthesis, represents a new strategy for treating inflammatory disorders. Herein we report the discovery of 2,4-thiazolidinedione-based mPGES-1/5-LO dual inhibitors following a multidisciplinary protocol, involving virtual combinatorial screening, chemical synthesis, and validation of the biological activities for the selected compounds. Following the multicomponent-based chemical route for the decoration of the 2,4-thiazolidinedione core, a large library of virtual compounds was built (∼2.0×10⁴ items) and submitted to virtual screening. Nine selected molecules were synthesized and biologically evaluated, disclosing among them four compounds able to reduce the activity of both enzymes in the mid- and low- micromolar range of activities. These results are of interest for further expanding the chemical diversity around the 2,4-thiazolidinedione central core, facilitating the identification of novel anti-inflammatory agents endowed with a promising and safer pharmacological profile.

Synthesis and Antimicrobial Activity of a New Series of Thiazolidine-2,4-diones Carboxamide and Amino Acid Derivatives

Novel thiazolidine-2,4-dione carboxamide and amino acid derivatives were synthesized in excellent yield using OxymaPure/N,N'-diisopropylcarbodimide coupling methodology and were characterized by chromatographic and spectrometric methods, and elemental analysis. The antimicrobial and antifungal activity of these derivatives was evaluated against two Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), two-Gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and one fungal isolate (Candida albicans). Interestingly, several samples demonstrated weak to moderate antibacterial activity against Gram-negative bacteria, as well as antifungal activity. However, only one compound namely, 2-(5-(3-methoxybenzylidene)-2,4-dioxothiazolidin-3-yl)acetic acid, showed antibacterial activity against Gram-positive bacteria, particularly S. aureus.

Thiazolidinediones as antidiabetic agents: A critical review

Thiazolidinediones (TZDs) or Glitazones are an important class of insulin sensitizers used in the treatment of Type 2 diabetes mellitus (T2DM). TZDs were reported for their antidiabetic effect through antihyperglycemic, hypoglycemic and hypolipidemic agents. In time, these drugs were known to act by increasing the transactivation activity of Peroxisome Proliferators Activated Receptors (PPARs). The clinically used TZDs that suffered from several serious side effects and hence withdrawn/updated later, were full agonists of PPAR-γ and potent insulin sensitizers. These drugs were developed at a time when limited data were available on the structure and mechanism of PPARs. In recent years, however, PPAR-α/γ, PPAR-α/δ and PPAR-δ/γ dual agonists, PPAR pan agonists, selective PPAR-γ modulators and partial agonists have been investigated. In addition to these, several non PPAR protein alternatives of TZDs such as FFAR1 agonism, GPR40 agonism and ALR2, PTP1B and α-glucosidase inhibition have been investigated to address the problems associated with the TZDs. Using these rationalized approaches, several investigations have been carried out in recent years to develop newer TZDs devoid of side effects. This report critically reviews TZDs, their history, chemistry, mechanism mediated through PPAR, recent advances and future prospects.

Discovery and synthesis of the first selective BAG domain modulator of BAG3 as an attractive candidate for the development of a new class of chemotherapeutics

The first selective BAG3BD modulator has been discovered.

Novel quinazolinone-based 2,4-thiazolidinedione-3-acetic acid derivatives as potent aldose reductase inhibitors

Aim: Targeting aldose reductase enzyme with 2,4-thiazolidinedione-3-acetic acid derivatives having a bulky hydrophobic 3-arylquinazolinone residue. Materials & methods: All the target compounds were structurally characterized by different spectroscopic methods and microanalysis, their aldose reductase inhibitory activities were evaluated, and binding modes were studied by molecular modeling. Results: All the synthesized compounds proved to inhibit the target enzyme potently, exhibiting IC50 values in the nanomolar/low nanomolar range. Compound 5i (IC50 = 2.56 nM), the most active of the whole series, turned out to be almost 70-fold more active than the only marketed aldose reductase inhibitor epalrestat. Conclusion: This work represents a promising matrix for developing new potential therapeutic candidates for prevention of diabetic complications through targeting aldose reductase enzyme.

[Formula: see text]

Synthesis and in vitro antiproliferative and antibacterial activity of new thiazolidine-2,4-dione derivatives

In our present research, we synthesised new thiazolidine-2,4-diones (12-28). All the newly synthesised compounds were evaluated for antiproliferative and antibacterial activity. Antiproliferative evaluation was carried out using normal human skin fibroblasts and tumour cell lines: A549, HepG2, and MCF-7. The IC₅₀ values were determined for tested compounds revealing antiproliferative activity. Moreover, safety index (SI) was calculated. Among all tested derivatives, the compound 18 revealed the highest antiproliferative activity against human lung, breast, and liver cancer cells. More importantly, the derivative 18 showed meaningfully lower IC₅₀ values when compared to the reference substance, irinotecan, and relatively high SI values. Moreover, newly synthesised compounds were screened for the bacteria growth inhibition in vitro. According to our screening results, most active compound was the derivative 18 against Gram-positive bacteria. Therefore, it may be implied that the novel compound 18 appears to be a very promising agent for anticancer treatment.

Identification of novel pyrazole–rhodanine hybrid scaffolds as potent inhibitors of aldose reductase: design, synthesis, biological evaluation and molecular docking analysis

A series of novel pyrazole–rhodanine derivatives was designed, synthesized, and biologically evaluated for their potential inhibitory effect on both aldehyde reductase (ALR1) and aldose reductase (ALR2).

Cytotoxicity of thiazolidinedione-, oxazolidinedione- and pyrrolidinedione-ring containing compounds in HepG2 cells

Liver damage occurred in some patients who took troglitazone (TGZ) for type II diabetes. The 2,4-thiazolidinedione (TZD) ring in TGZ's structure has been implicated in its hepatotoxicity. To further examine the potential role of a TZD ring in toxicity we used HepG2 cells to evaluate two series of compounds containing different cyclic imides. N-phenyl analogues comprised 3-(3,5-dichlorophenyl)-2,4-thiazolidinedione (DCPT); 3-(3,5-dichlorophenyl)-2,4-oxazolidinedione (DCPO) and N-(3,5-dichlorophenyl)succinimide (NDPS). Benzylic compounds, which closely resemble TGZ, included 5-(3,5-dichlorophenylmethyl)-2,4-thiazolidinedione (DCPMT); 5-(4-methoxyphenylmethyl)-2,4-thiazolidinedione (MPMT); 5-(4-methoxyphenylmethylene)-2,4-thiazolidinedione (MPMT-I); 5-(4-methoxyphenylmethyl)-2,4-oxazolidinedione (MPMO); 3-(4-methoxyphenylmethyl)succinimide (MPMS) and 3-(4-methoxyphenylmethylene)succinimide (MPMS-I). Cytotoxicity was assessed using the MTS assay after incubating the compounds (0-250μM) with HepG2 cells for 24h. Only certain TZD derivatives (TGZ, DCPT, DCPMT and MPMT-I) markedly decreased cell viability, whereas MPMT had low toxicity. In contrast, analogues without a TZD ring (DCPO, NDPS, MPMO, MPMS and MPMS-I) were not cytotoxic. These findings suggest that a TZD ring may be an important determinant of toxicity, although different structural features, chemical stability, cellular uptake or metabolism, etc., may also be involved. A simple clustering approach, using chemical fingerprints, assigned each compound to one of three classes (each containing one active compound and close homologues), and provided a framework for rationalizing the activity in terms of structure.

Induced fit docking, pharmacophore modeling, and molecular dynamic simulations on thiazolidinedione derivatives to explore key interactions with Tyr48 in polyol pathway

To obtain a scientific thought and expedition to explore key interactions with Tyr48 in aldose reductase (ALR), combined study of pharmacophore modeling, induced fit docking, and dynamics studies were performed on ALR. A stereo chemically and energetically valid model of ALR-NADP+ complex was developed using homology modeling technique. Statistically a significant five point pharmacophore model was designed on a set of 54 thiazolidinedione derivatives with good external and internal predictive ability. Rigid and induced fit docking protocols were applied on ALR protein for both with and without NADP+ cofactor to identify a suitable binding mode that facilitates the key hydrogen bond interactions with Tyr48. Docking of thiazolidinedione derivatives into ALR-NADP+ complex gave more promising results by reducing false positive binding of inhibitors into the co-factor binding site. Structural changes within Try48 and Asp43 during the binding process in enzyme inhibitor complex were analyzed using molecular dynamics (MD) simulations. The results obtained from dynamic simulations emphasized the role of Tyr48 in maintaining inter or intra molecular hydrogen bond interaction with the protein or inhibitor respectively. New molecules were designed and checked for their binding interactions and showed improved results compared to existing thiazolidinediones derivatives. Hence, these combined protocols will be helpful and cooperative to design and optimize molecules with better inhibitory activity against the biologically active target.

Benzothiazolyl substituted iminothiazolidinones and benzamido-oxothiazolidines as potent and partly selective aldose reductase inhibitors

Two new series of oxothiazolidine benzoate and acetate derivatives were synthesized and evaluated as aldehyde reductase (ALR1) and aldose reductase (ALR2) inhibitors.

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 of propiophenone derivatives as new class of antidiabetic agents reducing body weight in db/db mice

A series of propiophenone derivatives (6-23) have been synthesized and evaluated for their in vivo antihyperglycemic activities in sucrose loaded model (SLM), sucrose challenged streptozotocin (STZ-S) induced diabetic rat model and C57BL/KsJ db/db diabetic mice model. Compound 15 and 16 were emerged as potent antihyperglycemics and lipid lowering agents. These compounds (15, 16) further validate the potency by reducing body weight and food intake in db/db mice model. Possible mechanism of action for the propiophenone derivatives was established by the evaluation in various in vitro models. Interestingly some of the compounds were efficiently inhibiting PTP-1B.

Effect of structural modifications on 3-(3,5-dichlorophenyl)-2,4-thiazolidinedione-induced hepatotoxicity in Fischer 344 rats

Glitazones, used for type II diabetes, have been associated with liver damage in humans. A structural feature known as a 2,4-thiazolidinedione (TZD) ring may contribute to this toxicity. TZD rings are of interest since continued human exposure via the glitazones and various prototype drugs is possible. Previously, we found that 3-(3,5-dichlorophenyl)-2,4-thiazolidinedione (DCPT) was hepatotoxic in rats. To evaluate the importance of structure on DCPT toxicity, we therefore studied two series of analogs. The TZD ring was replaced with: a mercaptoacetic acid group {[[[(3,5-dichlorophenyl)amino]carbonyl]thio]acetic acid, DCTA}; a methylated TZD ring [3-(3,5-dichlorophenyl)-5-methyl-2,4-thiazolidinedione, DPMT]; and isomeric thiazolidinone rings [3-(3,5-dichlorophenyl)-2- and 3-(3,5-dichlorophenyl)-4-thiazolidinone, 2-DCTD and 4-DCTD, respectively]. The following phenyl ring-modified analogs were also tested: 3-phenyl-, 3-(4-chlorophenyl)-, 3-(3,5-dimethylphenyl)- and 3-[3,5-bis(trifluoromethyl)phenyl]-2,4-thiazolidinedione (PTZD, CPTD, DMPT and DFMPT, respectively). Toxicity was assessed in male Fischer 344 rats 24 h after administration of the compounds. In the TZD series only DPMT produced liver damage, as evidenced by elevated serum alanine aminotransferase (ALT) activities at 0.6 and 1.0 mmol kg(-1) (298.6 ± 176.1 and 327.3 ± 102.9 Sigma-Frankel units ml(-1) , respectively) vs corn oil controls (36.0 ± 11.3) and morphological changes in liver sections. Among the phenyl analogs, hepatotoxicity was observed in rats administered PTZD, CPTD and DMPT; with ALT values of 1196.2 ± 133.6, 1622.5 ± 218.5 and 2071.9 ± 217.8, respectively (1.0 mmol kg(-1) doses). Morphological examination revealed severe hepatic necrosis in these animals. Our results suggest that hepatotoxicity of these compounds is critically dependent on the presence of a TZD ring and also the phenyl substituents.

Pyranocoumarins: a new class of anti-hyperglycemic and anti-dyslipidemic agents

A series of pyranocoumarin derivatives were synthesized and evaluated in vivo for their anti-hyperglycemic as well as anti-dyslipidemic activities. Compounds 7a, 7c, 8a, 8b, 8c, 8e and 8f have shown promising anti-hyperglycemic activities in sucrose loaded model (SLM) as well as sucrose challenged streptozotocin induced diabetic rat model (STZ). Compounds 8a and 8b were showing 38.0% and 42.0% blood glucose lowering activity in db/db mice model. In vitro anti-hyperglycemic activity evaluation exhibited that compounds 8a (IC(50)=24.5 microM) and 8b (IC(50)=36.2 microM) are potential PTP-1B inhibitors thereby revealing their possible mechanism of anti-diabetic action. Compounds 7a, 7b, 8a, 8b, 8d, 8e and 8f have shown significant anti-dyslipidemic activity in triton induced dyslipidemia in rats.

CoMFA and CoMSIA analysis of 2,4-thiazolidinediones derivatives as aldose reductase inhibitors

Diabetes remains a life-threatening disease. The clinical profile of diabetic subjects is often worsened by the presence of several long-term complications, for example neuropathy, nephropathy, retinopathy, and cataract. Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were performed on a series of 2,4-thiazolidinediones derivatives as aldose reductase (ALR2) inhibitors. Molecular ligand superimposition on a template structure was finished by the database alignment method. The 3D-QSAR models resulted from 44 molecules gave q (2) values of 0.773 and 0.817, r (2) values of 0.981 and 0.979 for CoMFA and CoMSIA, respectively. The contour maps from the models indicated that a large volume group next to the R-substituent will increase the ALR2 inhibitory activity. In fact, adding a -CH(2)COOH substituent at the R-position would generate a new compound with higher predicted activity.

Effect of gender, dose, and time on 3-(3,5-dichlorophenyl)-2,4-thiazolidinedione (DCPT)-induced hepatotoxicity in Fischer 344 rats

1. The thiazolidinedione ring present in drugs available for type II diabetes can contribute to hepatic injury. Another thiazolidinedione ring-containing compound, 3-(3,5-dichlorophenyl)-2,4-thiazoli-dinedione (DCPT), produces liver damage in rats. Accordingly, the effects of gender, dose, and time on DCPT hepatotoxicity were therefore evaluated. 2. Male rats were more sensitive to DCPT (0.4-1.0 mmol kg(-1) by intraperitoneal administration) as shown by increased serum alanine aminotransferase levels and altered hepatic morphology 24 h post-dosing. Effects in both genders were dose dependent. In males, DCPT (0.6 mmol kg(-1)) produced elevations in alanine aminotransferases and changes in liver sections 3 h after dosing that progressively worsened up to 12 h. DCPT-induced renal effects were mild. 3. It is concluded that male rats are more susceptible to DCPT hepatotoxicity and that damage occurs rapidly. DCPT primarily affects the liver and can be a useful compound to investigate the role of the thiazolidinedione ring in hepatic injury. However, the gender dependency and rapid onset of DCPT hepatotoxicity require further investigation.

Role of biotransformation in 3-(3,5-dichlorophenyl)-2,4-thiazolidinedione-induced hepatotoxicity in Fischer 344 rats

Cytochrome P450 (CYP)-mediated metabolism in the thiazolidinedione (TZD) ring may contribute to the hepatotoxicity of the insulin-sensitizing agents such as troglitazone. We were interested in determining if biotransformation could also be a factor in the liver damage associated with another TZD ring containing compound, 3-(3,5-dichlorophenyl)-2,4-thiazolidinedione (DCPT). Therefore, hepatotoxic doses of DCPT (0.6 or 1.0 mmol/kg, i.p.) were administered to male Fischer 344 rats after pretreatment with vehicle, 1-aminobenzotriazole (ABT, non-selective CYP inhibitor) and troleandomycin (TAO, CYP3A inhibitor). Alternatively, rats were pretreated with vehicle or the CYP3A inducer dexamethasone (DEX) prior to a non-toxic DCPT dose (0.2 mmol/kg, i.p.). Vehicle-, ABT-, TAO- and DEX-only control groups were also run. Toxicity was assessed 24 h after DCPT administration. Both hepatotoxic doses of DCPT induced elevations in serum alanine aminotransferase (ALT) levels that were attenuated by ABT or TAO pretreatment. Liver sections from rats that received vehicle+DCPT revealed areas of gross necrosis and neutrophil invasion, whereas sections from ABT+DCPT and TAO+DCPT rats showed minor changes compared to controls. DEX pretreatment potentiated ALT levels associated with the non-toxic DCPT dose. Furthermore, DEX+DCPT rat liver sections exhibited hepatic injury when compared against rats that received vehicle+DCPT. Blood urea nitrogen levels, urinalysis and kidney morphology were not markedly altered by any combination of pretreatments or treatments. Enzyme activity and Western blotting experiments with rat liver microsomes confirmed the effects of the various pretreatments. Our results suggest that hepatic CYP3A isozymes may be involved in DCPT-induced liver damage in male rats. We believe this is the first report demonstrating that modulation of the biotransformation of a TZD ring-containing compound can alter hepatotoxicity in a common animal model.

5-Arylidene-2,4-thiazolidinediones as inhibitors of protein tyrosine phosphatases

4-(5-Arylidene-2,4-dioxothiazolidin-3-yl)methylbenzoic acids (2) were synthesized and evaluated in vitro as inhibitors of PTP1B and LMW-PTP, two protein tyrosine phosphatases (PTPs) which act as negative regulators of the metabolic and mitotic signalling of insulin. The synthesis of compounds 2 represents an example of utilizing phosphotyrosine-mimetics to identify effective low molecular weight nonphosphorus inhibitors of PTPs. Several thiazolidinediones 2 exhibited PTP1B inhibitory activity in the low micromolar range with moderate selectivity for human PTP1B and IF1 isoform of human LMW-PTP compared with other related PTPs.

Evaluation of in vitro aldose redutase inhibitory activity of 5-arylidene-2,4-thiazolidinediones

A number of 5-arylidene-2,4-thiazolidinediones containing a hydroxy or a carboxymethoxy group in their 5-benzylidene moiety have been synthesised and evaluated as in vitro aldose reductase (ALR2) inhibitors. Most of them exhibited strong inhibitory activity, with IC(50) values in the range between 0.20 and 0.70 microM. Molecular docking simulations into the ALR2 active site highlighted that the phenolic or carboxylic substituents of the 5-benzylidene moiety can favourably interact, in alternative poses, either with amino acid residues lining the lipophilic pocket of the enzyme, such as Leu300, or with the positively charged recognition region of the ALR2 active site.

Novel aldose reductase inhibitors derived from 6-[[(diphenylmethylene)amino]oxy]hexanoic acid

Starting from the recently identified aldose reductase inhibitor 6-[[(diphenylmethylene)amino]oxy]hexanoic acid 1, the following systematic structural modifications were performed: (a) formal substitution of the phenyl rings, (b) isosteric replacement of the benzene core by the heteroarenes pyridine and thiophene, (c) formal reduction of the aromatic substructure and subsequent diminution of the cyclohexyl ring, (d) introduction of methylene spacer between C=N and the phenyl rings, and finally (e) formal ring closure in order to get derivatives of the tricycles fluorenone, xanthone, and thioxanthone, respectively. Out of these series, compounds 22-24 bearing disubstituted phenyl rings exhibit the highest inhibitory activity (IC(50 )value approx. 3 muM) which lie almost in the range of the reference sorbinil.