Phenoxy pendant isatins as potent α-glucosidase inhibitors: reciprocal carbonyl⋯carbonyl interactions, antiparallel π⋯π stacking driven solid state self-assembly and biological evaluation

Novel isatin-triazole based thiosemicarbazones as potential anticancer agents: synthesis, DFT and molecular docking studies

Thiosemicarbazones of isatin have been found to exhibit versatile bioactivities. In this study, two distinct types of isatin-triazole hybrids 3a and 3b were accessed via copper-catalyzed azide-alkyne cycloaddition reaction (CuAAC), together with their mono and bis-thiosemicarbazone derivatives 4a-h and 5a-h. In addition to the characterization by physical, spectral and analytical data, a DFT study was carried out to obtain the optimized geometries of all thiosemicarbazones. The global reactivity values showed that among the synthesized derivatives, 4c, 4g and 5c having nitro substituents are the most soft compounds, with compound 5c having the highest electronegativity and electrophilicity index values among the synthesized series, thus possessing strong binding ability with biomolecules. Molecular docking studies were performed to explore the inhibitory ability of the selected compounds against the active sites of the anticancer protein of phosphoinositide 3-kinase (PI3K). Among the synthesized derivatives, 4-nitro substituted bisthiosemicarbazone 5c showed the highest binding energy of -10.3 kcal mol-1. These findings demonstrated that compound 5c could be used as a favored anticancer scaffold via the mechanism of inhibition against the PI3K signaling pathways.

Pyrano[2,3-b]chromone derivatives as novel dual inhibitors of α-glucosidase and α-amylase: Design, synthesis, biological evaluation, and in silico studies

Inhibition of α-glucosidase and α-amylase is an important target for treatment of type 2 diabetes. In this work, a novel series of pyrano[2,3-b]chromene derivatives 5a-m was designed based on potent α-glucosidase and α-amylase inhibitors and synthesized by simple chemical reactions. These compounds were evaluated against the latter enzymes. Most of the title compounds exhibited high inhibitory activity against α-glucosidase and α-amylase in comparison to standard inhibitor (acarbose). Representatively, the most potent compound, 4-methoxy derivative 5d, was 30.4 fold more potent than acarbose against α-glucosidase and 6.1 fold more potent than this drug against α-amylase. In silico molecular modeling demonstrated that compound 5d attached to the active sites of α-glucosidase and α-amylase with a favorable binding energies and established interactions with important amino acids. Dynamics of compound 5d also showed that this compound formed a stable complex with the α-glucosidase active site. In silicodrug-likeness as well as ADMET prediction of this compound was also performed and satisfactory results were obtained.

Synthesis and bio-evaluation of newer dihydropyridines and tetrahydropyridines based glycomimetic azasugars

This study presents the synthesis and bio-evaluation of new triazolylated dihydropyridine and tetrahydropyridine azasugar scaffolds (F1-14). Azasugar glycomimetics are the synthetic substances that mimic the structural and functional characteristics of natural carbohydrates showcasing promising potential as therapeutic agents for diabetes. The α-glucosidase inhibitory activity of synthesized final compounds were evaluated against the commercially available α-glucosidase enzyme. Majority of the screened compounds displayed excellent inhibition with IC50 values ranging from 2.12 to 75.11 μM, when compared to the standard drug Acarbose. Particularly, compound F5 with IC50 value of 2.12 μM was found to be the most active compound among the series. Further molecular docking studies of selected ligands were performed to investigate the binding interactions with enzyme active sites. Their specific binding patterns have been analysed with the binding sites of Saccharomyces cerevisiae α-glucosidase. These findings suggest these candidates as the potential leads for the anti-diabetic activity.

Arylureidoaurones: Synthesis, in vitro α-glucosidase, and α-amylase inhibition activity

Because of the colossal global burden of diabetes, there is an urgent need for more effective and safer drugs. We designed and synthesized a new series of aurone derivatives possessing phenylureido or bis-phenylureido moieties as α-glucosidase and α-amylase inhibitors. Most of the synthesized phenylureidoaurones have demonstrated superior inhibition activities (IC50s of 9.6-339.9 μM) against α-glucosidase relative to acarbose (IC50 = 750.0 μM) as the reference drug. Substitution of aurone analogues with two phenylureido substituents at the 5-position of the benzofuranone moiety and the 3' or 4' positions of the 2-phenyl ring resulted in compounds with almost 120-180 times more potent inhibitory activities than acarbose. The aurone analogue possessing two phenylureido substitutions at 5 and 4' positions (13) showed the highest inhibition activity with an IC50 of 4.2 ± 0.1 μM. Kinetic studies suggested their inhibition mode to be competitive. We also investigated the binding mode of the most potent compounds using the consensually docked 4D-QSAR methodology. Furthermore, these analogues showed weak-to-moderate non-competitive inhibitory activity against α-amylase. 5-Methyl substituted aurone with 4'-phenylureido moiety (6e) demonstrated the highest inhibition activity on α-amylase with an IC50 of 142.0 ± 1.6 μM relative to acarbose (IC50 = 108 ± 1.2 μM). Our computational studies suggested that these analogues interact with a hydrophilic allosteric site in α-amylase, located far from the enzyme active site at the N-terminal.

Synthesis of novel coumarin-hydrazone hybrids as α-glucosidase inhibitors and their molecular docking studies

Diabetes mellitus is a metabolic disorder and more than 90% of diabetic patients suffer from type-2 diabetes, which is characterized by hyperglycemia. α-Glucosidase inhibition has become an appropriate approach to tackle high blood glucose levels. The current study was focused on synthesizing coumarin-hydrazone hybrids (7a-i) by using facile chemical reactions. The synthesized compounds were characterized by using 1H-NMR, 13C-NMR, and IR. To evaluate their anti-diabetic capability, all of the conjugates were screened for in vitro α-glucosidase inhibitory activity to reveal their therapeutic importance. All of the compounds (except 7b) demonstrated significant enzyme inhibitory potential with IC50 values ranging between 2.39-57.52 μM, as compared to the standard inhibitor, acarbose (IC50 = 873.34 ± 1.67 μM). Among them, compound 7c is the most potent α-glucosidase inhibitor (IC50 = 2.39 ± 0.05 μM). Additionally, molecular docking was employed to scrutinize the binding pattern of active compounds within the α-glucosidase binding site. The in silico analysis reflects that hydrazone moiety is an essential pharmacophore for the binding of compounds with the active site residues of the enzyme. This study demonstrates that compounds 7c and 7f deserve further molecular optimization for potential application in diabetic management.

Synthesis, biological evaluation, and molecular docking study of chromen-linked hydrazine carbothioamides as potent α-glucosidase inhibitors

Inhibiting α-glucosidase is a reliable method for reducing blood sugar levels in diabetic individuals. Several novel chromen-linked hydrazine carbothioamide (3a-r) were designed and synthesized by condensation of chromone-3-carbaldehyde with a variety of substituted thiosemicarbazides. The structures of these new analogues were elucidated through various advanced spectroscopic techniques (1 H NMR, 13 C NMR, and ESI-MS). The resulted compounds were screened for α-glucosidase inhibitory potential and all the compounds (3a-r) exhibited potent inhibition of α-glucosidase with IC50 values ranging 0.29-53.70 µM. Among them compounds 3c, 3f, 3h, and 3r displayed the highest α-glucosidase inhibitor capability with IC50 values of 1.50, 1.28, 1.08, and 0.29 µM, respectively. Structure-activity relationship showed that different substituted groups are responsible for the variation in the α-glucosidase inhibition. The kinetics studies of the most active inhibitor (3r) were performed, to investigate the mode of inhibition and dissociation constants (Ki), that indicated a competitive inhibitor with Ki value of 1.47 ± 0.31 µM. Furthermore, molecular docking studies was performed to reveal the possible interactions, such as H-bonding, or π-π stacking, with the key residues of α-glucosidase. Docking analysis revealed the importance of hydrazine carbothioamide moiety of compounds in the attachment of ligands with the crucial residues of α-glucosidase. The estimated pharmacokinetic, physicochemical, and drug likeness properties of compounds 3a-r reflects that these molecules have acceptable range of these properties.

Synthesis of 1,2,3-triazole-1,3,4-thiadiazole hybrids as novel α-glucosidase inhibitors by in situ azidation/click assembly

α-Glucosidase inhibition is widely used in the oral management of diabetes mellitus (DM), a disease characterized by high blood sugar levels (hyperglycemia) and abnormal carbohydrate metabolism. In this respect, a series of 1,2,3-triazole-1,3,4-thiadiazole hybrids 7a-j were synthesized, inspired by a copper-catalyzed one-pot azidation/click assembly approach. All the synthesized hybrids were screened for inhibition of the α-glucosidase enzyme, displaying IC₅₀ values ranging from 63.35 ± 0.72 to 613.57 ± 1.98 μM, as compared to acarbose (reference) with IC₅₀ of 844.81 ± 0.53 μM. The hybrids 7h and 7e with 3-nitro and 4-methoxy substituents at the phenyl ring of the thiadiazole moiety were the best active hybrids of this series with IC₅₀ values of 63.35 ± 0.72 μM, and 67.61 ± 0.64 μM, respectively. Enzyme kinetics analysis of these compounds revealed a mixed mode of inhibition. Moreover, molecular docking studies were also performed to gain insights into the structure-activity-relationships of the potent compounds and their corresponding analogs.

Quinazolinone-1,2,3-triazole-acetamide conjugates as potent α-glucosidase inhibitors: synthesis, enzyme inhibition, kinetic analysis, and molecular docking study

In this study, new hybrids of quinazolinone-1,2,3-triazole-acetamide were designed, synthesized, and screened for their α-glucosidase inhibitory activity. The results obtained from the in vitro screening indicated that all analogs exhibited significant inhibitory activity against α-glucosidase (IC50 values ranging from 4.8-140.2 μM) in comparison to acarbose (IC50 = 750.0 μM). The limited structure-activity relationships suggested the variation in the inhibitory activities of the compounds affected by different substitutions on the aryl moiety. The enzyme kinetic studies of the most potent compound 9c, revealed that it inhibited α-glucosidase in a competitive mode with a K i value of 4.8 μM. In addition, molecular docking studies investigated the structural perturbation and behavior of all derivatives inside the α-glucosidase active site. Next, molecular dynamic simulations of the most potent compound 9c, were performed to study the behavior of the 9c-complex during the time. The results showed that these compounds can be considered as potential antidiabetic agents.

Synthetic α-glucosidase inhibitors as promising anti-diabetic agents: Recent developments and future challenges

Diabetes mellitus is one of the biggest challenges for the scientific community in the 21st century. It is a well-recognized multifactorial health problem contributes significantly to high mortality rates by causing serious health complications mainly related to cardiovascular diseases, kidney damage and neuropathy. The inhibition of α-glucosidase (enzyme that catalyses starch hydrolysis in the intestine) is an effective therapeutic approach for controlling hyperglycemia associated with type-2 diabetes. However, the presently approved drugs/inhibitors such as acarbose, miglitol and voglibose have several undesirable gastrointestinal side effects impeding their applications. Therefore, search for novel and more effective inhibitors with reduced side effects and less cost remains a fascinating area of research. In this context, a large variety of α-glucosidase inhibitors have been identified in recent years that demands attention from drug development community. This review is therefore an effort to summarize and highlight the promising α-glucosidase inhibitors especially those which are primarily based on aromatic heterocyclic scaffolds such as coumarin, imidazole, isatin, pyrimidine, quinazoline, triazine, thiazole etc, having improved safety and pharmacological profiles.

Bio-Oriented Synthesis of Novel Polyhydroquinoline Derivatives as α-Glucosidase Inhibitor for Management of Diabetes

Polyhydroquinoline derivatives (1-15) were synthesized through an unsymmetrical Hantzsch reaction in excellent yields by treating 3,5-dibromo-4-hydroxybenzaldehyde, dimedone, ammonium acetate, and ethyl acetoacetate in ethanol solvent. The structures of the synthesized compounds (1-15) were deduced through different spectroscopic techniques such as 1H NMR, 13C NMR, and HR-ESI-MS. The synthesized products were tested for their α-glucosidase inhibitory activity where compounds 11 (IC50 = 0.56 ± 0.01 μM), 10 (IC50 = 0.94 ± 0.01 μM), 4 (IC50 = 1.47 ± 0.01 μM), 2 (IC50 = 2.20 ± 0.03 μM), 6 (IC50 = 2.20 ± 0.03 μM), 12 (IC50 = 2.22 ± 0.07 μM), 7 (IC50 = 2.76 ± 0.04 μM), 9 (IC50 = 2.78 ± 0.03 μM), and 3 (IC50 = 2.88 ± 0.05 μM) exhibited high potential for the inhibition of α-glucosidase, while the rest of the compounds (8, 5, 14, 15, and 13) showed significant α-glucosidase inhibitory potential with IC50 values of 3.13 ± 0.10, 3.34 ± 0.06, 4.27 ± 0.13, 6.34 ± 0.15, and 21.37 ± 0.61 μM, respectively. Among the synthesized series, two compounds, i.e., 11 and 10, showed potent α-glucosidase inhibitory potential higher than the standard. All the compounds were compared with standard drug "acarbose" (IC50 = 873.34 ± 1.67 μM). An in silico method was used to predict their mode of binding within the active site of enzyme to understand their mechanism of inhibition. Our in silico observation complements with the experimental results.

Synthesis of new diphenyl urea-clubbed imine analogs and its Implications in diabetic management through in vitro and in silico approaches

Type II diabetes mellitus (T2DM) is a global health issue with high rate of prevalence. The inhibition of α-glucosidase enzyme has prime importance in the management of T2DM. This study was established to synthesize Schiff bases of 1,3-dipheny urea (3a-y) and to investigate their in vitro anti-diabetic capability via inhibiting α-glucosidase, a key player in the catabolism of carbohydrates. The structures of all compounds were confirmed through various techniques including, Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) and mass-spectrometry (MS) methods. Interestingly all these compounds displayed potent inhibition IC₅₀ values in range of 2.14-115 µM as compared to acarbose used as control. Additionally, all the compounds were docked at the active site of α-glucosidase to predict their mode of binding. The docking results indicates that Glu277 and Asn350 play important role in the stabilization of these compounds in the active site of enzyme. These molecules showed excellent predicted pharmacokinetics, physicochemical and drug-likeness profile. The anti-diabetic potential of these molecules signifies their medical importance and provide insights into prospective therapeutic options for the treatment of T2DM.

Synthesis of new phenoxymethylcoumarin clubbed 4-arylthiazolylhydrazines as α-glucosidase inhibitors and their kinetics and molecular docking studies

The current studies mainly demonstrate the coumarin based azomethine-clubbed thiazoles synthesis and their in-vitro evaluation for the first time against α-glucosidase. Due to the catalytic role of α-glucosidase, it has become a precise target for the treatment of type diabetes mellitus (T2DM). The high rate of prevalence of diabetes and its associated health related problems led us to scrutinize the anti-diabetic capability of the synthesized thiazole derivatives (6a-6k). The anticipated structures of prepared compounds were confirmed through FT-IR and NMR spectroscopic methods. All the compounds showed several times potent activity than the standard drug, acarbose (IC₅₀ = 873.34 ± 1.67 µM) against α-glucosidase with IC₅₀ values in range of 0.87 ± 0.02-322.61 ± 1.14 µM. The compound 6k displayed the highest anti-diabetic activity (IC₅₀ = 1.88 ± 0.03 µM). Kinetic study revealed that these are competitive inhibitors for α-glucosidase. The mode of binding of the synthesized molecules were further evaluated by molecular docking, which reflects the importance of azomethine group in protein-ligand interaction. The docking scores are complementary with the IC₅₀ values of compounds while the interaction pattern of the compounds clearly demonstrates their structure-activity relationship. Current study reported medicinal importance of thiazole derivative as future drug candidates for the management of Type 2 Diabetes Mellitus (T2DM).

Synthesis and bioactivities evaluation of quinazolin-4(3H)-one derivatives as α-glucosidase inhibitors

The development of new antidiabetes agents is necessary to obtain optimal glycemic control and overcome its complications. Different quinazolin-4(3H)-one bearing phenoxy-acetamide derivatives (7a–r) were designed and synthesized to develop α-glucosidase inhibitors. All the synthesized derivatives were evaluated against α-glucosidase in vitro and among them, compound 7b showed the highest α-glucosidase inhibition with an IC50 of 14.4 µM, which was ∼53 times stronger than that of acarbose. The inhibition kinetic studies showed that the inhibitory mechanism of compound 7b was a competitive type towards α-glucosidase. Also, molecular docking studies analyzed the interaction between the most potent derivative and α-glucosidase. Current findings indicate the new potential of quinazolin-4(3H)-ones that could be used for the development of novel agents against diabetes mellitus.

Molecular duplexes featuring NH···N, CH···O and CH···π interactions in solid-state self-assembly of triazine-based compounds

Synthetic supramolecular structures constructed through the cooperative action of numerous non-covalent forces are highly desirable as models to unravel and understand the complexity of systems created in nature via self-assembly. Taking advantage of the low cost of 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride) and the sequential nucleophilic substitution reactions with almost all types of nucleophiles, a series of six structurally related novel s-triazine derivatives 1-6 were synthesized and structurally characterized based on their physical, spectral and crystallographic data. The solid-state structures of all the six compounds showed intriguing and unique molecular duplexes featuring NH···N, CH···O and CH···π interactions. Careful analysis of different geometric parameters of the involved H-bonds indicates that they are linear, significant and are therefore responsible for guiding the three-dimensional structure of these compounds in the solid state. The prevalence of sextuple hydrogen bond array-driven molecular duplexes and the possibility of structural modifications on the s-triazine ring render these novel triazine derivatives 1-6 attractive as a platform to create heteroduplex constructs and their subsequent utility in the field of supramolecular chemistry and crystal engineering.