Design, synthesis and molecular modelling studies of novel 3-acetamido-4-methyl benzoic acid derivatives as inhibitors of protein tyrosine phosphatase 1B

Design, synthesis, and pharmacological evaluation of heteroaryl thiol-linked kojic acid derivatives as a novel class of acetylcholinesterase inhibitors for Alzheimer's disease therapy

Natural products have long served as versatile templates for discovering lead molecules against various targets of pharmacological interest. Kojic acid, a fungal metabolite epitomizes this versatility as it elicits broad-spectrum biological properties. Described herein is a series of heteroaryl thiol-linked kojic acid derivatives that demonstrate potent acetylcholinesterase (AChE) inhibition along with anti-amyloid-β (Aβ) aggregation activity and blood brain barrier (BBB) permeability highlighting their potential as a novel class of Anti-Alzheimer's therapeutics. Seventeen kojic acid derivatives, synthesized by incorporating three different heterocyclic thiols, were evaluated for in vitro AChE inhibition employing Ellman's method. The most potent analogs identified from the AChE inhibition studies were further evaluated for binding to the peripheral anionic site (PAS) of AChE using the propidium iodide (PI) displacement assay, anti-amyloid-β (Aβ) aggregation inhibition using the thioflavin T assay, and BBB permeability using the PAMPA-BBB assay. Obtained findings indicated that two compounds MS 21-05 and MS 21-11 bearing a 5-methoxybenzo[d]thiazol-2-yl)thio moiety and 5-phenyl-1,3,4-oxadiazol- 2-yl)thio moiety, respectively, elicited potent AChE inhibition (IC₅₀ < 5 µM), moderate anti-Aβ aggregation effects and good BBB permeability. The molecular docking studies of compound MS 21 - 11 along with its molecular dynamics simulations at peripheral anionic site (PAS) of enzyme AChE provided structural insights into the binding mode of these derivatives. Taken together, the findings of this study establish heteroaryl thiol-linked kojic acid derivatives as a valuable molecular framework for developing anti-Alzheimer's therapeutics that target both cholinergic dysfunction and amyloid-β aggregation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-025-04295-5.

Does Metabolic Manager Show Encouraging Outcomes in Alzheimer's?: Challenges and Opportunity for Protein Tyrosine Phosphatase 1b Inhibitors

Protein tyrosine phosphatase 1b (PTP1b) is a member of the protein tyrosine phosphatase (PTP) enzyme group and encoded as PTP1N gene. Studies have evidenced an overexpression of the PTP1b enzyme in metabolic syndrome, anxiety, schizophrenia, neurodegeneration, and neuroinflammation. PTP1b inhibitor negatively regulates insulin and leptin pathways and has been explored as an antidiabetic agent in various clinical trials. Notably, the preclinical studies have shown that recuperating metabolic dysfunction and dyshomeostasis can reverse cognition and could be a possible approach to mitigate multifaceted Alzheimer's disease (AD). PTP1b inhibitor thus has attracted attention in neuroscience, though the development is limited to the preclinical stage, and its exploration in large clinical trials is warranted. This review provides an insight on the development of PTP1b inhibitors from different sources in diabesity. The crosstalk between metabolic dysfunction and insulin insensitivity in AD and type-2 diabetes has also been highlighted. Furthermore, this review presents the significance of PTP1b inhibition in AD based on pathophysiological facets, and recent evidences from preclinical and clinical studies.

Computational Methods in Cooperation with Experimental Approaches to Design Protein Tyrosine Phosphatase 1B Inhibitors in Type 2 Diabetes Drug Design: A Review of the Achievements of This Century

Protein tyrosine phosphatase 1B (PTP1B) dephosphorylates phosphotyrosine residues and is an important regulator of several signaling pathways, such as insulin, leptin, and the ErbB signaling network, among others. Therefore, this enzyme is considered an attractive target to design new drugs against type 2 diabetes, obesity, and cancer. To date, a wide variety of PTP1B inhibitors that have been developed by experimental and computational approaches. In this review, we summarize the achievements with respect to PTP1B inhibitors discovered by applying computer-assisted drug design methodologies (virtual screening, molecular docking, pharmacophore modeling, and quantitative structure–activity relationships (QSAR)) as the principal strategy, in cooperation with experimental approaches, covering articles published from the beginning of the century until the time this review was submitted, with a focus on studies conducted with the aim of discovering new drugs against type 2 diabetes. This review encourages the use of computational techniques and includes helpful information that increases the knowledge generated to date about PTP1B inhibition, with a positive impact on the route toward obtaining a new drug against type 2 diabetes with PTP1B as a molecular target.

Thioethers: An Overview

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Spreading rapidly in recent years, cancer has become one of the causes of the highest mor-tality rates after cardiovascular diseases. The reason for cancer development is still not clearly under-stood despite enormous research activities in this area. Scientists are now working on the biology of cancer, especially on the root cause of cancer development. The aim is to treat the cancer disease and thus cure the patients. The continuing efforts for the development of novel molecules as potential anti-cancer agents are essential for this purpose. The main aim of this review was to present a survey on the medicinal chemistry of thioethers and provide practical data on their cytotoxicities against various cancer cell lines. The research articles published between 2001-2020 were consulted to pre-pare this review article; however, patent literature has not been included. The thioether-containing heterocyclic compounds may emerge as a new class of potent and effective anti-cancer agents in the future.

Virtual Screening Based Discovery of PTP1B Inhibitors and Their Biological Evaluations

Background :

The discovery of novel antidiabetics for the treatment of type 2 diabetes mellitus (T2DM) is an important task nowadays because the current treatment approaches have certain limitations. The reported studies showed that the protein tyrosine phosphatase 1B (PTP1B) is a valuable target, can be used to develop significant antidiabetic molecules.

Objective:

In the present investigation, computational methods and biological evaluation studies have been applied to develop novel PTP1B inhibitors with good enzyme binding affinity and activity.

Methods:

Virtual screening (docking) analysis of SPECS database compounds on PTP1B enzyme was performed using Schrodinger software. In vitro and in vivo biological evaluations had been conducted with the identified hits.

Results:

The results revealed that the molecules identified through these studies have shown significant interactions with the active site residues of the PTP1B enzyme. The compounds S1 and S2 provided significant binding interactions with the residues (Arg221 and Gln262) and have shown considerable in vitro PTP1B inhibitory activity and in vivo antidiabetic activity. The compounds S1 and S2 possessed 35.44±0.12% and 33.68±0.08% inhibitory activities, respectively.

Conclusion:

These identified hits will be used as a template for design and development of novel PTP1B inhibitors with a compatible pharmacokinetic profile.

Structure-based molecular modeling in SAR analysis and lead optimization

In silico methods like molecular docking and pharmacophore modeling are established strategies in lead identification. Their successful application for finding new active molecules for a target is reported by a plethora of studies. However, once a potential lead is identified, lead optimization, with the focus on improving potency, selectivity, or pharmacokinetic parameters of a parent compound, is a much more complex task. Even though in silico molecular modeling methods could contribute a lot of time and cost-saving by rationally filtering synthetic optimization options, they are employed less widely in this stage of research. In this review, we highlight studies that have successfully used computer-aided SAR analysis in lead optimization and want to showcase sound methodology and easily accessible in silico tools for this purpose.

Design, Synthesis and Biological Evaluation of 3-(2-(benzo[d]thiazol-2- ylthio)acetamido)benzoic Acid Derivatives as Inhibitors of Protein Tyrosine Phosphatase 1B

Background:

Protein Tyrosine Phosphatase 1B (PTP1B) is an attractive target for antidiabetic drug discovery owing to its pivotal role as a negative regulator of insulin and leptin signaling.

Objective:

The objective of this research is to design, synthesize, and evaluate some acetamidobenzoic acid derivatives as a novel class of protein tyrosine phosphatase 1B inhibitors with therapeutic potential for Type II diabetes.

Methods:

3-(2-(Benzo[d]thiazol-2-ylthio)acetamido)benzoic acid derivatives 4(a-j) were synthesized and characterized by employing spectral studies. All the synthesized compounds were screened for in vitro PTP1B inhibitory activity and the most potent compound in the series was also evaluated for in vivo anti-hyperglycemic activity using STZ induced diabetic Wistar rat model. Molecular docking studies were also performed with the most potent analog using FlexX docking algorithm to delineate its binding mode to the active site of the PTP1B.

Results:

Among all the synthesized compounds, 3-(2-(benzo[d]thiazol-2-ylthio)acetamido)-4- methylbenzoic acid (4f) displayed good PTP1B inhibitory activity with an IC50 value of 11.17 μM. The compound also exhibited good anti hyperglycemic efficacy in streptozotocin induced diabetic Wistar rats. Docking studies with 4f revealed that the compound bound in the catalytic and second aryl binding site of the PTP1B.

Conclusion:

Overall, compound 4f with good in vitro PTP1B inhibitory potency and in vivo antihyperglycemic efficacy would be a valuable lead molecule for the development of acetamidobenzoic acid based PTP1B inhibitors with antidiabetic potential.

Crystal structure and Hirshfeld surface analysis of 2-[(1,3-benzoxazol-2-yl)sulfan-yl]-N-(2-meth-oxy-phen-yl)acetamide

In the title compound, C16H14N2O3S, the 1,3-benzoxazole ring system is essentially planar (r.m.s deviation = 0.004 Å) and makes a dihedral angle of 66.16 (17)° with the benzene ring of the meth-oxy-phenyl group. Two intra-molecular N-H⋯O and N-H⋯N hydrogen bonds occur, forming S(5) and S(7) ring motifs, respectively. In the crystal, pairs of C-H⋯O hydrogen bonds link the mol-ecules into inversion dimers with R 2 2(14) ring motifs, stacked along the b-axis direction. The inversion dimers are linked by C-H⋯π and π-π-stacking inter-actions [centroid-to-centroid distances = 3.631 (2) and 3.631 (2) Å], forming a three-dimensional network. Two-dimensional fingerprint plots associated with the Hirshfeld surface show that the largest contributions to the crystal packing come from H⋯H (39.3%), C⋯H/H⋯C (18.0%), O⋯H/H⋯O (15.6) and S⋯H/H⋯S (10.2%) inter-actions.

2,4-Thiazolidinediones as PTP 1B Inhibitors: A Mini Review (2012-2018)

2,4-thiazolidinedione (TZD) scaffold is a synthetic versatile scaffold explored by medicinal chemists for the discovery of novel molecules for the target-specific approach to treat or manage number of deadly ailments. PTP 1B is the negative regulator of insulin signaling cascade, and its diminished activity results in abolishment of insulin resistance associated with T2DM. The present review focused on the seven years journey (2012-2018) of TZDs as PTP 1B inhibitors with the insight into the amendments in the structural framework of TZD scaffold in order to optimize/design potential PTP 1B inhibitors. We have investigated the synthesized molecules based on TZD scaffold with potential activity profile against PTP 1B. Based on the SAR studies, the combined essential pharmacophoric features of selective and potent TZDs have been mapped and presented herewith for further design and synthesis of novel inhibitors of PTP 1B. Compound 46 bearing TZD scaffold with N-methyl benzoic acid and 5-(3-methoxy-4-phenethoxy) benzylidene exhibited the most potent activity (IC50 1.1 µM). Imidazolidine-2,4-dione, isosteric analogue of TZD, substituted with 1-(2,4-dichlorobenzyl)-5-(3-(2,4- dichlorobenzyloxy)benzylidene) (Compound 15) also endowed with very good PTP inhibitory activity profile (IC50 0.57 µM). It is noteworthy that Z-configuration is essential in structural framework around the double bond of arylidene for the designing of bi-dentate ligands with optimum activity.

Novel Mixed-Type Inhibitors of Protein Tyrosine Phosphatase 1B. Kinetic and Computational Studies

The Atlas of Diabetes reports 415 million diabetics in the world, a number that has surpassed in half the expected time the twenty year projection. Type 2 diabetes is the most frequent form of the disease; it is characterized by a defect in the secretion of insulin and a resistance in its target organs. In the search for new antidiabetic drugs, one of the principal strategies consists in promoting the action of insulin. In this sense, attention has been centered in the protein tyrosine phosphatase 1B (PTP1B), a protein whose overexpression or increase of its activity has been related in many studies with insulin resistance. In the present work, a chemical library of 250 compounds was evaluated to determine their inhibition capability on the protein PTP1B. Ten molecules inhibited over the 50% of the activity of the PTP1B, the three most potent molecules were selected for its characterization, reporting Ki values of 5.2, 4.2 and 41.3 µM, for compounds 1, 2, and 3, respectively. Docking and molecular dynamics studies revealed that the three inhibitors made interactions with residues at the secondary binding site to phosphate, exclusive for PTP1B. The data reported here support these compounds as hits for the design more potent and selective inhibitors against PTP1B in the search of new antidiabetic treatment.

Recent advances in the development of protein tyrosine phosphatase 1B inhibitors for Type 2 diabetes

Diabetes mellitus is the most serious and prevalent metabolic disorders worldwide, complications of which can decrease significantly the quality of life and contribute to premature death. Resistance to insulin is a predominant pathophysiological factor of Type 2 diabetes (T2D). Protein tyrosine phosphatase 1B (PTP1B) is an important negative factor of insulin signal and a potent therapeutic target in T2D patients. This review highlights recent advances (2012-2015) in research related to the role of PTP1B in signal transduction processes implicated in pathophysiology of T2D, and novel PTP1B inhibitors with an emphasis on their chemical structures and modes of action.

Molecular docking assisted 3D-QSAR study of benzylidene-2,4-thiazolidinedione derivatives as PTP-1B inhibitors for the management of Type-2 diabetes mellitus

An integrated molecular docking assisted 3D-QSAR study was performed on benzylidene-2,4-thiazolidinediones to identify spatial fingerprints for designing PTP-1B inhibitors.