Dihydrobenzoxazinone derivatives as aldose reductase inhibitors with antioxidant activity

Influence of Nitrosyl Iron Complex with Thiosulfate Ligands on Therapeutically Important Targets Related to Type 2 Diabetes Mellitus

The high prevalence of type 2 diabetes mellitus (T2DM), and the lack of effective therapy, determine the need for new treatment options. The present study is focused on the NO-donors drug class as effective antidiabetic agents. Since numerous biological systems are involved in the pathogenesis and progression of T2DM, the most promising approach to the development of effective drugs for the treatment of T2DM is the search for pharmacologically active compounds that are selective for a number of therapeutic targets for T2DM and its complications: oxidative stress, non-enzymatic protein glycation, polyol pathway. The nitrosyl iron complex with thiosulfate ligands was studied in this work. Binuclear iron nitrosyl complexes are synthetic analogues of [2Fe-2S] centers in the regulatory protein natural reservoirs of NO. Due to their ability to release NO without additional activation under physiological conditions, these compounds are of considerable interest for the development of potential drugs. The present study explores the effects of tetranitrosyl iron complex with thiosulfate ligands (TNIC-ThS) on T2DM and its complications regarding therapeutic targets in vitro, as well as its ability to bind liposomal membrane, inhibit lipid peroxidation (LPO), and non-enzymatic glycation of bovine serum albumin (BSA), as well as aldose reductase, the enzyme that catalyzes the reduction in glucose to sorbitol in the polyol pathway. Using the fluorescent probe method, it has been shown that TNIC-ThS molecules interact with both hydrophilic and hydrophobic regions of model membranes. TNIC-ThS inhibits lipid peroxidation, exhibiting antiradical activity due to releasing NO (IC50 = 21.5 ± 3.7 µM). TNIC-ThS was found to show non-competitive inhibition of aldose reductase with Ki value of 5.25 × 10^-4 M. In addition, TNIC-ThS was shown to be an effective inhibitor of the process of non-enzymatic protein glycation in vitro (IC50 = 47.4 ± 7.6 µM). Thus, TNIC-ThS may be considered to contribute significantly to the treatment of T2DM and diabetic complications.

Synthesis, antidiabetic activity and molecular docking studies of novel aryl benzylidenethiazolidine-2,4-dione based 1,2,3-triazoles

A series of novel aryl benzylidenethiazolidine-2,4-dione based 1,2,3-triazoles synthesized in a straightforward route consisting of benzylidenethiazolidine-2,4-dione and 1,2,3-triazole pharmacophores. The new scaffolds tested for in vitro antidiabetic activity by inhibition of aldose reductase enzyme and its inhibition measured in half of Inhibition Concentration (IC₅₀). The activity results correlated with standard reference Sorbinil (IC₅₀: 3.45 ± 0.25 µM). Among all the titled compounds 8f (1.42 ± 0.21 µM), 8d (1.85 ± 0.39 µM), 13a (1.94 ± 0.27 µM) and 8b (1.98 ± 0.58 µM) shown potent activity. In addition, molecular docking results against the crystal structure of aldose reductase (PDB ID: 1PWM) revealed that the binding affinities shown by all synthesized compounds are higher than the reference compound Sorbinil. The docking scores, H-bond interactions, and hydrophobic interactions well defined inhibition strength of all compounds.

Dissociation Mode of the O-H Bond in Betanidin, pKa-Clusterization Prediction, and Molecular Interactions via Shape Theory and DFT Methods

Betanidin (Bd) is a nitrogenous metabolite with significant bioactive potential influenced by pH. Its free radical scavenging activity and deprotonation pathway are crucial to studying its physicochemical properties. Motivated by the published discrepancies about the best deprotonation routes in Bd, this work explores all possible pathways for proton extractions on that molecule, by using the direct approach method based on pK_a. The complete space of exploration is supported by a linear relation with constant slope, where the pK_a is written in terms of the associated deprotonated molecule energy. The deprotonation rounds 1, …, 6 define groups of parallel linear models with constant slope. The intercepts of the models just depend on the protonated energy for each round, and then the pK_a can be trivially ordered and explained by the energy. We use the direct approximation method to obtain the value of pK_a. We predict all possible outcomes based on a linear model of the energy and some related verified assumptions. We also include a new measure of similarity or dissimilarity between the protonated and deprotonated molecules, via a geometric-chemical descriptor called the Riemann-Mulliken distance (RMD). The RMD considers the cartesian coordinates of the atoms, the atomic mass, and the Mulliken charges. After exploring the complete set of permutations, we show that the successive deprotonation process does not inherit the local energy minimum and that the commutativity of the paths does not hold either. The resulting clusterization of pK_a can be explained by the local acid and basic groups of the BD, and the successive deprotonation can be predicted by using the chemical explained linear models, which can avoid unnecessary optimizations. Another part of the research uses our own algorithm based on shape theory to determine the protein's active site automatically, and molecular dynamics confirmed the results of the molecular docking of Bd in protonated and anionic form with the enzyme aldose reductase (AR). Also, we calculate the descriptors associated with the SET and SPLET mechanisms.

Length and rigidity of the spacer impact on aldose reductase inhibition of the 5F-like ARIs in a dual-occupied mode

The primary objective of this study was to investigate the structure-activity relationship of a new series of 5F-like Aldose Reductase Inhibitors (ARIs) using in silico docking method. In this perspective, 6 novel ARIs have been designed and synthesized. Evaluation of the inhibition of these compounds to ALR2 was carried on with epalrestat and 5F as the references. It was found that the spacer of 5F-like ARIs has a great influence on their inhibitory activity. Rigid spacer with length equal to 3 ∼ 4 carbon alkyl chain brings about better inhibitory activity. Among them, compound 4b was verified as the most active ARIs, where its IC₅₀ value was 16.8 ± 1.3 nM. Furthermore, in silico docking studies using AutoDock 4.2 as well as molecular simulation using GROMACS 2022.1 showed that 5F-like ARIs adopt a dual-occupation mode. The interaction energy (-25 to -74 kcal/mol), as well as MM-GBSA binding free energy (-37 to -65 kcal/mol) was positively correlated with their ALR2 inhibition constant (2000 to 16.8 nM). Docking interaction explained well the structure-activity relationship. A pharmacophore model has been set up for 5F-like ARIs thereafter. This model indicates that as an effective ARI, the entity should have four characteristics: an aromatic center, two hydrogen bond donors, and one hydrogen bond acceptor. By the way, all the 5F-like ARIs reported here are good to mild antioxidant with EC₅₀ value between 13.6 ± 1.2 and 71.1 ± 3.2 μM. All our data direct the further development of more optimal ARIs for the treatment of diabetic complication in the future.

Design of Improved Antidiabetic Drugs: A Journey from Single to Multitarget Agents

Multifactorial diseases exhibit a complex pathophysiology with several factors contributing to their pathogenesis and development. Examples of such disorders are neurodegenerative (e. g. Alzheimer's, Parkinson's) and cardiovascular diseases (e. g. atherosclerosis, metabolic syndrome, diabetes II). Traditional therapeutic approaches with single-target drugs have been proven, in many cases, unsatisfactory for the treatment of multifactorial diseases such as diabetes II. The well-established by now strategy of multitarget drugs is constantly gaining interest and momentum, as a more effective approach. The development of pharmacomolecules able to simultaneously modulate multiple relevant-to-the-disease targets has already several successful examples in various fields and has, as such, inspired the design of multitarget antidiabetic agents; this review highlights the design aspect and efficacy of this approach for improved antidiabetics by presenting several examples of successful pharmacophore combinations in (multitarget) agents that modulate two or more molecular targets involved in diabetes II, resulting in a superior antihyperglycemic profile.

Ultrasound-promoted convenient and ionic liquid [BMIM]BF4 assisted green synthesis of diversely functionalized pyrazolo quinoline core via one-pot multicomponent reaction, DFT study and pharmacological evaluation

An ultrasound-assisted green protocol for one-pot synthesis of a new series of pharmaceutically relevant pyrazolo quinoline derivatives (4a-t) were synthesized, characterized, and evaluated using DFT and biological activities. Pyrazolo quinoline derivatives (4a-t) were synthesized via a three-component tandem reaction of 1,3-dicarbonyl compound (1a-b), substituted aromatic aldehyde (2a-o), and 5-amino indazole (3a) in the presence of 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM]BF₄ ionic liquid in ethanol at ambient conditions. The main purpose of the present work is selective functionalization of pyrazolo quinoline (4a-t) core excluding another potential parallel reaction under environmentally benign reaction conditions. The present protocol shows features such as amphiphilic behavior of ionic liquid during reaction transformation, and reusability of the [BMIM]BF₄ ionic liquid under mild reaction condition. All newly derived compounds were evaluated for their in vitro anti-inflammatory and antioxidant activity. Among them, compound 4c showed encouraging antioxidant activity compared with standard antioxidant ascorbic acid, and compounds 4n and 4r displayed very good anti-inflammatory activity compared with a standard drug. In this study, a theoretical computational density functional study was also executed to perform the geometry optimizations, frontier molecular orbital approach, and molecular electrostatic potential (MESP). The DFT study was carried out with the basis set DFT/B3LYP/6-31+G (d, p) level of theory. The quantum chemical descriptors (QCDS) and MESP diagrams were plotted to examine the biological reactivities of representative pyrazolo quinolines (4a-t).

Novel Hydroxychalcone-Based Dual Inhibitors of Aldose Reductase and α-Glucosidase as Potential Therapeutic Agents against Diabetes Mellitus and Its Complications

We designed a novel series of bifunctional inhibitors of α-glucosidase and aldose reductase (ALR2) based on the structure of hydroxychalcone. The two enzymes relate to blood glucose level and anomalously elevated polyol pathway of glucose metabolism under hyperglycemia, respectively. Most compounds in the series exhibited a potent inhibitory activity for both enzymes, and a significant antioxidant property was shown. Further in vivo studies of 11j and 14d using streptozotocin (STZ)-induced diabetic rats as a model found that 11j achieved not only good antihyperglycemic and glucose tolerance effect in a dose-dependent manner (p < 0.01) but also showed effective inhibition of polyol pathway. 14d significantly suppressed the maltose-induced postprandial glucose elevation. Additionally, they effectively improved lipid metabolisms and restored an antioxidant ability. Therefore, the two compounds may be promising agents for the prevention and treatment of diabetic complications.

Styryl Group, a Friend or Foe in Medicinal Chemistry

The styryl (Ph-CH=CH-R) group is widely represented in medicinally important compounds, including drugs, clinical candidates, and molecular probes as it positively impacts the lipophilicity, oral absorption, and biological activity. The analysis of matched molecular pairs (styryl vs. phenethyl, phenyl, methyl, H) for the biological activity indicates the superiority aspect of styryl compounds. However, the Michael acceptor site in the styryl group makes it amenable to the nucleophilic attack by biological nucleophiles and transformation to the toxic metabolites. One of the downsides of styryl compounds is isomerization that impacts the molecular conformation and directly affects biological activity. The impact of cis-trans isomerism and isosteric replacements on biological activity is exemplified. We also discuss the styryl group-bearing drugs, clinical candidates, and fluorescent probes. Overall, the present review reveals the utility of the styryl group in medicinal chemistry and drug discovery.

Physiological and Pathological Roles of Aldose Reductase

Aldose reductase (AR) is an aldo-keto reductase that catalyzes the first step in the polyol pathway which converts glucose to sorbitol. Under normal glucose homeostasis the pathway represents a minor route of glucose metabolism that operates in parallel with glycolysis. However, during hyperglycemia the flux of glucose via the polyol pathway increases significantly, leading to excessive formation of sorbitol. The polyol pathway-driven accumulation of osmotically active sorbitol has been implicated in the development of secondary diabetic complications such as retinopathy, nephropathy, and neuropathy. Based on the notion that inhibition of AR could prevent these complications a range of AR inhibitors have been developed and tested; however, their clinical efficacy has been found to be marginal at best. Moreover, recent work has shown that AR participates in the detoxification of aldehydes that are derived from lipid peroxidation and their glutathione conjugates. Although in some contexts this antioxidant function of AR helps protect against tissue injury and dysfunction, the metabolic transformation of the glutathione conjugates of lipid peroxidation-derived aldehydes could also lead to the generation of reactive metabolites that can stimulate mitogenic or inflammatory signaling events. Thus, inhibition of AR could have both salutary and injurious outcomes. Nevertheless, accumulating evidence suggests that inhibition of AR could modify the effects of cardiovascular disease, asthma, neuropathy, sepsis, and cancer; therefore, additional work is required to selectively target AR inhibitors to specific disease states. Despite past challenges, we opine that a more gainful consideration of therapeutic modulation of AR activity awaits clearer identification of the specific role(s) of the AR enzyme in health and disease.