Antiglycation and antioxidant potential of novel imidazo[4,5-b]pyridine benzohydrazones

Multi-Targeting Neuroprotective Effects of Syzygium aromaticum Bud Extracts and Their Key Phytocompounds against Neurodegenerative Diseases

Alzheimer's disease (AD) is a neurodegenerative disease that causes a gradual loss of normal motor and cognitive function. The complex AD pathophysiology involves various factors such as oxidative stress, neuroinflammation, amyloid-beta (Aβ) aggregation, disturbed neurotransmission, and apoptosis. The available drugs suffer from a range of side effects and are not able to cover different aspects of the disease. Therefore, finding a safer therapeutic approach that can affect multiple targets at a time is highly desirable. In the present study, the underlying neuroprotective mechanism of an important culinary spice, Syzygium aromaticum (Clove) extract, and major bioactive compounds were studied in hydrogen peroxide-induced oxidative stress in human neuroblastoma SH-SY5Y cell lines as a model. The extracts were subjected to GC-MS to identify important bioactive components. The extracts and key bio-actives reduced reactive oxygen species (ROS), restored mitochondrial membrane potential (MMP), and provided neuroprotection from H2O2-induced oxidative stress in cell-based assays due to the antioxidant action. They also reduced lipid peroxidation significantly and restored GSH content. Clove extracts have also displayed anti-acetylcholinesterase (AChE) activity, anti-glycation potential, and Aβ aggregation/fibrilization inhibition. The multitarget neuroprotective approach displayed by Clove makes it a potential candidate for AD drug development.

Synthesis of Fluorinated Hydrazinylthiazole Derivatives: A Virtual and Experimental Approach to Diabetes Management

A novel series of fluorophenyl-based thiazoles was synthesized following the Hanztsch method. All of the compounds were initially verified with physical parameters (color, melting point, retardation factor (R _f)), which were further confirmed by several spectroscopic methods, including ultraviolet-visible (UV-visible), Fourier-transform infrared (FTIR), ¹H, ¹³C, ¹⁹F NMR, and high-resolution mass spectrometry (HRMS). The binding interactions of all compounds were studied using a molecular docking simulation approach. Furthermore, each compound was evaluated for its alpha(α)-amylase, antiglycation, and antioxidant potentials. The biocompatibility of all compounds was checked with an in vitro hemolytic assay. All synthesized scaffolds were found biocompatible with minimal lysis of human erythrocytes as compared to the standard Triton X-100. Among the tested compounds, the analogue 3h (IC₅₀ = 5.14 ± 0.03 μM) was found to be a highly potent candidate against α-amylase as compared to the standard (acarbose, IC₅₀ = 5.55 ± 0.06 μM). The compounds 3d, 3f, 3i, and 3k exhibited excellent antiglycation inhibition potential with their IC₅₀ values far less than the standard amino guanidine (IC₅₀ = 0.403 ± 0.001 mg/mL). The antidiabetic potential was further supported by docking studies. Docking studies revealed that all synthesized compounds exhibited various interactions along enzyme active sites (pi-pi, H-bonding, van der Waals) with varied binding energies.

Synthesis of thiazole-based-thiourea analogs: as anticancer, antiglycation and antioxidant agents, structure activity relationship analysis and docking study

This work reports the convenient approach for the synthesis of thiazole based thiourea derivatives (1-21) from 2-bromo-1-(4-fluorophenyl)thiazole-1-one and phenyl isothiocyanates. The scope and diversity were achieved from readily available phenyl isothiocyanates. This protocol involves an oxidative C-S bond formation. Moreover, hybrid thiazole based thiourea scaffolds (1-21) according to literature known protocol were screened in vitro for anticancer Potential against breast cancer, antiglycation and antioxidant inhibitory profile. All newly developed scaffolds were showed moderate to good inhibitory potentials ranging from 0.10 ± 0.01 µM to 11.40 ± 0.20 µM, 64.20 ± 0.40 µM to 385.10 ± 1.70 µM and 8.90 ± 0.20 µM to 39.20 ± 0.50 µM against anticancer, antiglycation and antioxidant respectively. Among the series, compounds 12 (IC50 = 0.10 ± 0.01 µM), 10 (IC50 = 64.20 ± 0.40 µM) and 12 (IC50 = 8.90 ± 0.20 µM) with flouro substitution at phenyl ring of thiourea were identified to be the most potent among the series having excellent anticancer, antiglycation and antioxidant potential. The structure of all the newly synthetics scaffolds were confirmed by using different types of spectroscopic techniques such as HREI-MS, 1H- and 13C-NMR spectroscopy. To find structure-activity relationship, molecular docking studies were carried out to understand the binding mode of active inhibitors with active site of enzymes and results supported the experimental data.Communicated by Ramaswamy H. Sarma.

Bioevaluation of synthetic pyridones as dual inhibitors of α-amylase and α-glucosidase enzymes and potential antioxidants

Herein, a library of novel pyridone derivatives 1-34 was designed, synthesized, and evaluated for α-amylase and α-glucosidase inhibitory as well as antioxidant activities. Pyridone derivatives 1-34 were synthesized via a one-pot multi-component reaction of variously substituted aromatic aldehydes, acetophenone, ethyl cyanoacetate, and ammonium acetate in absolute ethanol. Synthetic compounds 1-34 were structurally characterized by different spectroscopic techniques. Most of the tested compounds showed more promising inhibition potential than the standard acarbose (IC₅₀  = 14.87 ± 0.16 µM) but compounds 13 and 12 were found to be the most potent compounds with IC₅₀ values of 9.20 ± 0.14 µM and 3.05 ± 0.18 µM against α-amylase and α-glucosidase enzymes, respectively. Compounds 1-34 also displayed moderate antioxidant potential in the range of IC₅₀  = 96.50 ± 0.45 to 189.98 ± 1.00 µM in comparison to the control butylated hydroxytoluene (BHT) (IC₅₀  = 66.50 ± 0.36 µM), in DPPH radical scavenging activities. Additionally, all synthetic derivatives were subjected to a molecular docking study to investigate the interaction details of compounds 1-34 (ligands) with the active site of enzymes (receptors). These results indicate that the newly synthesized pyridone class may serve as promising lead candidates for controlling diabetes mellitus and as antioxidants.

Imidazopyridine, a promising scaffold with potential medicinal applications and structural activity relationship (SAR): recent advances

Imidazopyridine scaffold has gained tremendous importance over the past few decades. Imidazopyridines have been expeditiously used for the rationale design and development of novel synthetic analogs for various therapeutic disorders. A wide variety of imidazopyridine derivatives have been developed as potential anti-cancer, anti-diabetic, anti-tubercular, anti-microbial, anti-viral, anti-inflammatory, central nervous system (CNS) agents besides other chemotherapeutic agents. Imidazopyridine heterocyclic system acts as a key pharmacophore motif for the identification and optimization of lead structures to increase medicinal chemistry toolbox. The present review highlights the medicinal significances of imidazopyridines for their rationale development as lead molecules with improved therapeutic efficacies. This review further emphasis on the structure-activity relationships (SARs) of the various designed imidazopyridines to establish a relationship between the key structural features versus the biological activities.Communicated by Ramaswamy H. Sarma.

2-Mercaptobenzimidazole clubbed hydrazone for Alzheimer’s therapy: In vitro, kinetic, in silico, and in vivo potentials

Alzheimer’s is a type of dementia that affects the affected person’s thinking, memory, and behavior. It is a multifactorial disease, developed by the breakdown of the neurotransmitter acetylcholine via acetylcholinesterase (AChE). The present study was designed to evaluate potential inhibitors of acetylcholinesterase that could be used as a therapeutic agent against Alzheimer’s disease (AD). For this course, synthetic compounds of the Schiff bases class of 2-mercaptobenzimidazole hydrazone derivatives (9–14) were determined to be potent acetylcholinesterase inhibitors with IC₅₀ values varying between 37.64 ± 0.2 and 74.76 ± 0.3 μM. The kinetic studies showed that these are non-competitive inhibitors of AChE. Molecular docking studies revealed that all compounds accommodate well in the active site and are stabilized by hydrophobic interactions and hydrogen bonding. Molecular dynamics (MD) simulations of selected potent inhibitors confirm their stability in the active site of the enzyme. Moreover, all compounds showed antispasmodic and Ca²⁺ antagonistic activities. Among the selected compounds of 2-mercaptobenzimidazole hydrazone derivatives, compound 11 exhibited the highest activity on spontaneous and K⁺-induced contractions, followed by compound 13. Therefore, the Ca²⁺ antagonistic, AChE inhibition potential, and safety profile of these compounds in the human neutrophil viability assay make them potential drug candidates against AD in the future.

Pharmacological Potential and Synthetic Approaches of Imidazo[4,5-b]pyridine and Imidazo[4,5-c]pyridine Derivatives

The structural resemblance between the fused imidazopyridine heterocyclic ring system and purines has prompted biological investigations to assess their potential therapeutic significance. They are known to play a crucial role in numerous disease conditions. The discovery of their first bioactivity as GABA_A receptor positive allosteric modulators divulged their medicinal potential. Proton pump inhibitors, aromatase inhibitors, and NSAIDs were also found in this chemical group. Imidazopyridines have the ability to influence many cellular pathways necessary for the proper functioning of cancerous cells, pathogens, components of the immune system, enzymes involved in carbohydrate metabolism, etc. The collective results of biochemical and biophysical properties foregrounded their medicinal significance in central nervous system, digestive system, cancer, inflammation, etc. In recent years, new preparative methods for the synthesis of imidazopyridines using various catalysts have been described. The present manuscript to the best of our knowledge is the complete compilation on the synthesis and medicinal aspects of imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines reported from the year 2000 to date, including structure–activity relationships.

Synthesis and in vitro acetylcholinesterase and butyrylcholinesterase inhibitory potential of hydrazide based Schiff bases

To discover multifunctional agents for the treatment of Alzheimer's disease, a series of hydrazide based Schiff bases were designed and synthesized based on multitarget-directed strategy. We have synthesized twenty-eight analogs of hydrazide based Schiff bases, characterized by various spectroscopic techniques and evaluated in vitro for acetylcholinesterase and butyrylcholinesterase inhibition. All compounds showed varied degree of acetylcholinesterase and butyrylcholinesterase inhibition when compared with standard Eserine. Among the series, compounds 10, 3 and 24 having IC50 values 4.12±0.01, 8.12±0.01 and 8.41±0.06μM respectively showed potent acetylcholinesterase inhibition when compared with Eserine (IC50=0.85±0.0001μM). Three compounds 13, 24 and 3 having IC50 values 6.51±0.01, 9.22±0.07 and 37.82±0.14μM respectively showed potent butyrylcholinesterase inhibition by comparing with eserine (IC50=0.04±0.0001μM). The remaining compounds also exhibited moderate to weak inhibitory potential. Structure activity relationship has been established. Through molecular docking studies the binding interaction was confirmed.

Benzimidazole derivatives as new α-glucosidase inhibitors and in silico studies

Newly synthesized benzimidazole hydrazone derivatives 1-26 were evaluated for their α-glucosidase inhibitory activity. Compounds 1-26 exhibited varying degrees of yeast α-glucosidase inhibitory activity with IC50 values between 8.40 ± 0.76 and 179.71 ± 1.11 μM when compared with standard acarbose. In this assay, seven compounds that showed highest inhibitory effects than the rest of benzimidazole series were identified. All the synthesized compounds were characterized by different spectroscopic methods adequately. We further evaluated the interaction of the active compounds with enzyme with the help of docking studies.