Design, synthesis, and molecular docking studies of diphenylquinoxaline-6-carbohydrazide hybrids as potent α-glucosidase inhibitors

Substituted piperazine conjugated to quinoline-thiosemicarbazide as potent α-glucosidase inhibitors to target hyperglycemia

Diabetes mellitus, particularly type 2 diabetes, is a growing global health challenge characterized by chronic hyperglycemia due to insulin resistance. One therapeutic approach to managing this condition is the inhibition of α-glucosidase, an enzyme involved in carbohydrate digestion, to reduce postprandial blood glucose levels. In this study, a series of thiosemicarbazide-linked quinoline-piperazine derivatives were synthesized and evaluated for their α-glucosidase inhibitory activity, to identify new agents for type 2 diabetes management. Structure-activity relationship (SAR) analysis revealed that the nature and position of substituents on the aryl ring significantly impacted the inhibitory potency. Among the synthesized derivatives, the 2,5-dimethoxy phenyl substitution (7j) exhibited the most potent activity with an IC50 value of 50.0 µM, demonstrating a 15-fold improvement compared to the standard drug acarbose. Kinetic studies identified compound 7j as a competitive inhibitor, with a Ki value of 32 µM. Molecular docking simulations demonstrated key interactions between compound 7j and the active site of α-glucosidase, while molecular dynamics simulations confirmed the stability of the enzyme-ligand complex, reflected in low RMSD and RMSF values.

A Captivating Potential of Schiff Bases Derivatives for Antidiabetic Activity

A double bond between the nitrogen and carbon atoms characterizes a wide class of compounds known as Schiff bases. The flexibility of Schiff bases is formed from several methods and may be combined with alkyl or aryl substituents. The group is a part of organic compounds, either synthetic or natural, and it serves as a precursor and an intermediate in drugs that have therapeutic action. The review focuses on molecular docking and structure-activity relationship (SAR) analysis for antidiabetic effects of the different nonmetal Schiff bases. Many studies have found that Schiff bases are used as linkers in an extensive range of synthesized compounds and other activities. Thus, this current study aims to give the scientific community a thoughtful look at the principal ideas put forward by investigators regarding antidiabetic actions exhibited by certain Schiff-based derivatives, as this review covered many aspects, including docking and SAR analysis. For individuals who intend to create novel antidiabetic compounds with Schiff bases as pharmacophores or physiologically active moieties, it will be an invaluable informational resource.

Imidazo[1,2-c]quinazolines as a novel and potent scaffold of α-glucosidase inhibitors: design, synthesis, biological evaluations, and in silico studies

α-Glucosidase inhibition is an approved treatment for type 2 diabetes mellitus (T2DM). In an attempt to develop novel anti-α-glucosidase agents, two series of substituted imidazo[1,2-c]quinazolines, namely 6a-c and 11a-o, were synthesized using a simple, straightforward synthetic routes. These compounds were thoroughly characterized by IR, 1H and 13C NMR spectroscopy, as well as mass spectrometry and elemental analysis. Subsequently, the inhibitory activities of these compounds were evaluated against Saccharomyces cerevisiae α-glucosidase. In present study, acarbose was utilized as a positive control. These imidazoquinazolines exhibited excellent to great inhibitory potencies with IC50 values ranging from 12.44 ± 0.38 μM to 308.33 ± 0.06 μM, which were several times more potent than standard drug with IC50 value of 750.0 ± 1.5 μM. Representatively, compound 11j showed remarkable anti-α-glucosidase potency with IC50 = 12.44 ± 0.38 μM, which was 60.3 times more potent than positive control acarbose. To explore the potential inhibition mechanism, further evaluations including kinetic analysis, circular dichroism, fluorescence spectroscopy, and thermodynamic profile were carried out for the most potent compound 11j. Moreover, molecular docking studies and in silico ADME prediction for all imidazoquinazolines 6a-c and 11a-o were performed to reveal their important binding interactions, as well as their physicochemical and drug-likeness properties, respectively.

Synthesis and tyrosinase inhibitory activities of novel isopropylquinazolinones

To find new anti-browning and whitening agents in this study, new series of isopropylquinazolinone derivatives were designed and synthesized. All derivatives were evaluated as possible tyrosinase inhibitors and compound 9q bearing 4-fluorobenzyl moieties at the R position exhibited the best potencies with an IC₅₀ value of 34.67 ± 3.68 µM. The kinetic evaluations of 9q as the most potent derivatives recorded mix-type inhibition. Compounds 9o and 9q also exhibited potent antioxidant capacity with IC₅₀ values of 38.81 and 40.73 µM, respectively confirming their antioxidant potential. Molecular docking studies of 9q as the most potent derivative were exacuated and it was shown that quinazolinone and acetamide moieties of compound 9q participated in interaction with critical His residues of the binding site. The obtained results demonstrated that the 9q can be considered a suitable pharmacophore to develop potent tyrosinase inhibitors.

Synthesis, in vitro inhibitor screening, structure-activity relationship, and molecular dynamic simulation studies of novel thioquinoline derivatives as potent α-glucosidase inhibitors

New series of thioquinoline structures bearing phenylacetamide 9a-p were designed, synthesized and the structure of all derivatives was confirmed using different spectroscopic techniques including FTIR, ¹H-NMR, ¹³C-NMR, ESI-MS and elemental analysis. Next, the α-glucosidase inhibitory activities of derivatives were also determined and all the synthesized compounds (IC₅₀ = 14.0 ± 0.6-373.85 ± 0.8 μM) were more potent than standard inhibitors acarbose (IC₅₀ = 752.0 ± 2.0 μM) against α-glucosidase. Structure-activity relationships (SARs) were rationalized by analyzing the substituents effects and it was shown that mostly, electron-donating groups at the R position are more favorable compared to the electron-withdrawing group. Kinetic studies of the most potent derivative, 9m, carrying 2,6-dimethylphenyl exhibited a competitive mode of inhibition with K_i value of 18.0 µM. Furthermore, based on the molecular dynamic studies, compound 9m depicted noticeable interactions with the α-glucosidase active site via several H-bound, hydrophobic and hydrophilic interactions. These interactions cause interfering catalytic potential which significantly decreased the α-glucosidase activity.

Synthesis, in vitro α-glucosidase inhibitory activities, and molecular dynamic simulations of novel 4-hydroxyquinolinone-hydrazones as potential antidiabetic agents

In the present study, new structural variants of 4-hydroxyquinolinone-hydrazones were designed and synthesized. The structure elucidation of the synthetic derivatives 6a-o was carried out using different spectroscopic techniques including FTIR, ¹H-NMR, ¹³C-NMR, and elemental analysis, and their α-glucosidase inhibitory activity was also determined. The synthetic molecules 6a-o exhibited good α-glucosidase inhibition with IC₅₀ values ranging between 93.5 ± 0.6 to 575.6 ± 0.4 µM as compared to the standard acarbose (IC₅₀ = 752.0 ± 2.0 µM). Structure-activity relationships of this series were established which is mainly based on the position and nature of the substituent on the benzylidene ring. A kinetic study of the active compounds 6l and 6m as the most potent derivatives were also carried out to confirm the mode of inhibition. The binding interactions of the most active compounds within the active site of the enzyme were determined by molecular docking and molecular dynamic simulations.

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.

Synthesis and structure-activity relationship studies of benzimidazole-thioquinoline derivatives as α-glucosidase inhibitors

In this article, different s-substituted benzimidazole-thioquinoline derivatives were designed, synthesized, and evaluated for their possible α-glucosidase inhibitory activities. The most active compound in this series, 6j (X = 4-bromobenzyl) exhibited significant potency with an IC₅₀ value of 28.0 ± 0.6 µM compared to acarbose as the positive control with an IC₅₀ value of 750.0 µM. The kinetic study showed a competitive inhibition pattern against α-glucosidase for the 6j derivative. Also, the molecular dynamic simulations were performed to determine key interactions between compounds and the targeted enzyme. The in silico pharmacodynamics and ADMET properties were executed to illustrate the druggability of the novel derivatives. In general, it can be concluded that these derivatives can serve as promising leads to the design of potential α-glucosidase inhibitors.

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.