Synthesis, antioxidant and Aβ anti-aggregation properties of new ferulic, caffeic and lipoic acid derivatives obtained by the Ugi four-component reaction

Innovative approaches to Alzheimer's therapy: Harnessing the power of heterocycles, oxidative stress management, and nanomaterial drug delivery system

Alzheimer's disease (AD) presents a complex pathology involving amyloidogenic proteolysis, neuroinflammation, mitochondrial dysfunction, and cholinergic deficits. Oxidative stress exacerbates AD progression through pathways like macromolecular peroxidation, mitochondrial dysfunction, and metal ion redox potential alteration linked to amyloid-beta (Aβ). Despite limited approved medications, heterocyclic compounds have emerged as promising candidates in AD drug discovery. This review highlights recent advancements in synthetic heterocyclic compounds targeting oxidative stress, mitochondrial dysfunction, and neuroinflammation in AD. Additionally, it explores the potential of nanomaterial-based drug delivery systems to overcome challenges in AD treatment. Nanoparticles with heterocyclic scaffolds, like polysorbate 80-coated PLGA and Resveratrol-loaded nano-selenium, show improved brain transport and efficacy. Micellar CAPE and Melatonin-loaded nano-capsules exhibit enhanced antioxidant properties, while a tetra hydroacridine derivative (CHDA) combined with nano-radiogold particles demonstrates promising acetylcholinesterase inhibition without toxicity. This comprehensive review underscores the potential of nanotechnology-driven drug delivery for optimizing the therapeutic outcomes of novel synthetic heterocyclic compounds in AD management. Furthermore, the inclusion of various promising heterocyclic compounds with detailed ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) data provides valuable insights for planning the development of novel drug delivery treatments for AD.

Discovery of dual-action phenolic 4-arylidene-isoquinolinones with antioxidant and α-glucosidase inhibition activities

A multicomponent-derived synthesis of arylidene isoquinolinones decorated with phenolic moieties is described. The series demonstrated good DPPH trapping and, in the case of sinapic acid-containing analogs, excellent activity against lipoperoxidation; EPR also demonstrated that one derivative scavenged hydroxyl radicals. In addition, some compounds showed excellent inhibition of α-glucosidase activity and, according to both Lineweaver-Burk plots and molecular docking, they act as non-competitive or mixed inhibitors. In vitro assay also demonstrated that two compounds significantly reduced the plasma glucose levels after sucrose administration. In summary, the studied isoquinolinones become novel compounds with dual action (antioxidant and α-glucosidase inhibition) against diabetes and related metabolic diseases, whose optimization would lead to more potent candidates.

Recent Advances in the Synthesis of Antioxidant Derivatives: Pharmacological Insights for Neurological Disorders

Neurological disorders, characterized by oxidative stress (OS) and inflammation, have become a major global health concern. Redox reactions play a vital role in regulating the balance of the neuronal microenvironment. Specifically, the imbalance leads to a significant weakening of the organism's natural defensive mechanisms. This, in turn, causes the development of harmful oxidative stress, which plays a crucial role in the onset and progression of neurodegenerative diseases. The quest for effective therapeutic agents has led to significant advancements in the synthesis of antioxidant derivatives. This review provides a comprehensive overview of the recent developments in the use of novel antioxidant compounds with potential pharmacological applications in the management of neurological disorders. The discussed compounds encompass a diverse range of chemical structures, including polyphenols, vitamins, flavonoids, and hybrid molecules, highlighting their varied mechanisms of action. This review also focuses on the mechanism of oxidative stress in developing neurodegenerative disease. The neuroprotective effects of these antioxidant derivatives are explored in the context of specific neurological disorders, including Alzheimer's disease, Parkinson's disease, and Huntington's disease. The ultimate goal is to provide effective treatments for these debilitating conditions and improve the quality of life for patients.

Multifunctional agents against Alzheimer's disease based on oxidative stress: Polysubstituted pyrazine derivatives synthesized by multicomponent reactions

As Alzheimer's disease (AD) is a neurodegenerative disease with a complex pathogenesis, the exploration of multi-target drugs may be an effective strategy for AD treatment. Multifunctional small molecular agents can be obtained by connecting two or more active drugs or privileged pharmacophores by multicomponent reactions (MCRs). In this paper, two series of polysubstituted pyrazine derivatives with multifunctional moieties were designed as anti-AD agents and synthesized by Passerini-3CR and Ugi-4CR. Since the oxidative stress plays an important role in the pathological process of AD, the antioxidant activities of the newly synthesized compounds were first evaluated. Subsequently, selected active compounds were further screened in a series of AD-related bioassays, including Aβ1-42 self-aggregation and deaggregation, BACE-1 inhibition, metal chelation, and protection of SH-SY5Y cells from H2O2-induced oxidative damage. Compound A3B3C1 represented the best one with multifunctional potencies. Mechanism study showed that A3B3C1 acted on Nrf2/ARE signaling pathway, thus increasing the expression of related antioxidant proteins NQO1 and HO-1 to normal cell level. Furthermore, A3B3C1 showed good in vitro human plasma and liver microsome stability, indicating a potential for further development as multifunctional anti-AD agent.

Application of Quinoline Ring in Structural Modification of Natural Products

Natural compounds are rich in pharmacological properties that are a hot topic in pharmaceutical research. The quinoline ring plays important roles in many biological processes in heterocycles. Many pharmacological compounds, including saquinavir and chloroquine, have been marketed as quinoline molecules with good anti-viral and anti-parasitic properties. Therefore, in this review, we summarize the medicinal chemistry of quinoline-modified natural product quinoline derivatives that were developed by several research teams in the past 10 years and find that these compounds have inhibitory effects on bacteria, viruses, parasites, inflammation, cancer, Alzheimer's disease, and others.

Ferulic acid derivatives block coronaviruses HCoV-229E and SARS-CoV-2 replication in vitro

A novel coronavirus, SARS-CoV-2, emerged in China at the end of 2019 causing a large global outbreak. As treatments are of the utmost importance, drugs with broad anti-coronavirus activity embody a rich and rapid drug discovery landscape, where candidate drug compounds could be identified and optimized. To this end, we tested ten small-molecules with chemical structures close to ferulic acid derivatives (FADs) (n = 8), caffeic acid derivatives (CAFDs) (n = 1) and carboxamide derivatives (CAMDs) (n = 1) for their ability to reduce HCoV-229E replication, another member of the coronavirus family. Among these ten drugs tested, five of them namely MBA112, MBA33, MBA27-1, OS4-1 and MBA108-1 were highly cytotoxic and did not warrant further testing. In contrast, we observed a moderate cytotoxicity for two of them, MBA152 and 5c. Three drugs, namely MBA140, LIJ2P40, and MBA28 showed lower cytotoxicity. These candidates were then tested for their antiviral propreties against HCoV-229E and SARS-CoV2 replication. We first observed encouraging results in HCoV-229E. We then measured a reduction of the viral SARS-CoV2 replication by 46% with MBA28 (EC50 > 200 µM), by 58% with MBA140 (EC50 = 176 µM), and by 82% with LIJ2P40 (EC50 = 66.5 µM). Overall, the FAD LIJ2P40 showed a reduction of the viral titer on SARS-CoV-2 up to two logs with moderate cytotoxicity which opens the door to further evaluation to fight Covid-19.

Multicomponent reactions as a privileged tool for multitarget-directed ligand strategies in Alzheimer's disease therapy

Among neurodegenerative pathologies affecting the older population, Alzheimer's disease is the most common type of dementia and leads to neurocognitive and behavioral disorders. It is a complex and progressive age-related multifactorial disease characterized by a series of highly interconnected pathophysiological processes. Within the last decade, the multitarget-directed ligand strategy has emerged as a viable approach to developing complex molecules that exhibit several pharmacophores which can target the different enzymes and receptors involved in the pathogenesis of the disease. Herein, we focus on using multicomponent reactions such as Hantzsch, Biginelli and Ugi to develop these biologically active multitopic ligands.

The Role of a Pathological Interaction between β-amyloid and Mitochondria in the Occurrence and Development of Alzheimer's Disease

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases in existence. It is characterized by an impaired cognitive function that is due to a progressive loss of neurons in the brain. Extracellular β-amyloid (Aβ) plaques are the main pathological features of the disease. In addition to abnormal protein aggregation, increased mitochondrial fragmentation, altered expression of the genes involved in mitochondrial biogenesis, disruptions in the ER-mitochondria interaction, and mitophagy are observed. Reactive oxygen species are known to affect Aβ expression and aggregation. In turn, oligomeric and aggregated Aβ cause mitochondrial disorders. In this review, we summarize available knowledge about the pathological effects of Aβ on mitochondria and the potential molecular targets associated with proteinopathy and mitochondrial dysfunction for the pharmacological treatment of Alzheimer's disease.

Promising heterocycle-based scaffolds in recent (2019-2021) anti-Alzheimer's drug design and discovery

Alzheimer's disease (AD) is one of the neurodegenerative diseases that led to morbidity and mortality world-wide. It is a complex disease whose etiology is not completely known that leads to difficulty in prevent or cure of the AD. Also, there are only few approved drugs for AD treatment. Apart from deaths due to AD, expenditure of treatment and care of AD patients is higher than that of treatment of HIV and cancer diseases combined. Hence, it leads to an economic burden also. Although research is being carried out on designing drugs for AD, most of them have ended up in poor inhibitors with high toxicity. Hence, researchers should shoulder a great responsibility of discovery of efficient drugs for AD treatment. In the field of drug discovery, heterocycles played an important role. Also, most of the heterocyclic scaffolds have been used in design of potent anti-AD agents. In view of this, heterocyclic molecules reported recently are compiled and evaluated comprehensively. Especially, the molecules which exhibited pronounced activity are emphasized and described with respect to structure-activity relationship (SAR) in brief.

Bioactive phenylpropanoid derivatives from the fruits of Lycium ruthenicum Murr

Eight new (1-7 and 15) and 18 known (8-14 and 16-26) phenylpropanoid derivatives were isolated from the fruits of Lycium ruthenicum Murr. (black wolfberry). Their structures were determined by comprehensive spectroscopic analyses, chemical methods, and comparisons of spectroscopic data. Four known compounds (16, 17, 24, and 26) were firstly isolated from the genus Lycium. Interestingly, compounds 1/2 and 4/5 were isolated as two pairs of inseparable anomers owing to the tautomerism of the free hemiacetal at C-1'' in solution. The antioxidant, α-glucosidase inhibitory, and acetylcholinesterase (AChE) inhibitory activities of compounds 1-26 were evaluated. Some compounds possessed DPPH radical scavenging activity, and all compounds (1-26) exhibited different levels of oxygen radical absorbance capacity (ORAC). One compound displayed α-glucosidase inhibitory activity with potency close to that of the positive control (acarbose).

Therapeutic potential of ferulic acid and its derivatives in Alzheimer's disease-A systematic review

Alzheimer's disease (AD) is a progressive neurodegenerative disorder primarily caused by accumulation of amyloid-beta (Aβ) peptide extracellularly and neurofibrillary tangles intracellularly. Recently, it has been shown that oxidative stress and mitochondrial dysregulation play an important role in pathology of AD. Therefore, modulating various targets such as Aβ aggregation, neuro-inflammation, and oxidative stress, genetic factors such as Apolipoprotein E gene (ApoE) are some of the ways to manage AD. Studying the natural products which can act as multifunctional agents could be key toward discovering new therapeutics. Ferulic acid (FA) represents one such natural product, which has exhibited great potential in this regard. Found in the plant cell walls, FA is an antioxidant, free radical scavenger with anti-inflammatory activity. Taking this into consideration, over the years, various derivatives have been reported as anti-AD molecules based on structure of FA. The present review explores the role of FA and its derivatives as therapeutic agents in AD.

Beyond Antioxidant Effects: Nature-Based Templates Unveil New Strategies for Neurodegenerative Diseases

The complex network of malfunctioning pathways occurring in the pathogenesis of neurodegenerative diseases (NDDs) represents a huge hurdle in the development of new effective drugs to be used in therapy. In this context, redox reactions act as crucial regulators in the maintenance of neuronal microenvironment homeostasis. Particularly, their imbalance results in the severe compromising of organism’s natural defense systems and subsequently, in the instauration of deleterious OS, that plays a fundamental role in the insurgence and progress of NDDs. Despite the huge efforts in drug discovery programs, the identification process of new therapeutic agents able to counteract the relentless progress of neurodegenerative processes has produced low or no effective therapies. Consequently, a paradigm-shift in the drug discovery approach for these diseases is gradually occurring, paving the way for innovative therapeutical approaches, such as polypharmacology. The aim of this review is to provide an overview of the main pharmacological features of most promising nature-based scaffolds for a possible application in drug discovery, especially for NDDs, highlighting their multifaceted effects against OS and neuronal disorders.

A review on ferulic acid and analogs based scaffolds for the management of Alzheimer's disease

Alzheimer's disease (AD) is an age-related multifactorial neurodegenerative disorder characterized by severe central cholinergic neuronal loss, gradually contributing to cognitive dysfunction and impaired motor activity, resulting in the brain's cell death at the later stages of AD. Although the etiology of AD is not well understood, however, several factors such as oxidative stress, deposition of amyloid-β (Aβ) peptides to form Aβ plaques, intraneuronal accumulation of hyperphosphorylated tau protein, and low level of acetylcholine are thought to play a major role in the pathogenesis of AD. There is practically no drug for AD treatment that can address the basic factors responsible for the neurodegeneration and slow down the disease progression. The currently available therapies for AD in the market focus on providing only symptomatic relief without addressing the aforesaid basic factors responsible for the neurodegeneration. Ferulic acid (FA) is a phenol derivative from natural sources and serves as a potential pharmacophore that exerts multiple pharmacological properties such as antioxidant, neuroprotection, Aβ aggregation modulation, and anti-inflammatory. Several FA based hybrid analogs are under investigation as a multi-target directed ligand (MTDLs) to develop novel hybrid compounds for the treatment of AD. In the present review article, we are focused on the critical pathogenic factors responsible for the onset of AD followed by the developments of FA pharmacophore-based hybrids compounds as a novel multifunctional therapeutic agent to address the limitations associated with available treatment for AD. The rationale behind the development of these compounds and their pharmacological activities in particular to their ChE inhibition (ChEI), neuroprotection, antioxidant property, Aβ aggregation modulation, and metal chelation ability, are discussed in detail. We have also discussed the discovery of caffeic and cinnamic acids based MTDLs for AD. This review paper provides an in-depth insight into the research progress and current status of these novel therapeutics in AD and prospects for developing a druggable molecule with desired pharmacological affinity and reduced toxicity for the management of AD.

Multicomponent Reactions for Integrating Multiple Functional Groups into an Antioxidant

A large number of convincing evidences has revealed the correlation of the pathogeny of diseases with the oxidative damages of DNA, protein, biomembrane, and other biological species, while supplementation of antioxidants is demonstrated to be a promising way to avoid, at least, rectify the unbalance redox status in vivo. Although many endeavors have focused on synthesis of antioxidants, a main hurdle still hinders the wide usages of synthetic antioxidants because of low bioavailability and potential cytotoxicity. The search for antioxidants with multiple functional groups being recognized by different receptors becomes a much sought by researchers, and multicomponent reactions (MCRs) provide with powerful tools for the construction of multifunctional antioxidants. Presented herein is a personal account on the application of MCRs for the synthesis of multifunctional antioxidants, while radical-induced oxidation of DNA acts as the experimental system for evaluating antioxidative effect. Concretely, the Biginelli three-component reaction (3CR) affords such a dihydropyrimidine scaffold that the tautomerization between C=S and C-SH leads to antioxidative effect. The Povarov 3CR is able to integrate multiple antioxidative groups, i. e., ferrocenyl and -N(CH₃ )₂ , into a quinoline scaffold, while the Groebke 3CR provides with imidazo[1,2-a]pyridine skeleton for inhibiting DNA oxidation. Additionally, the Knoevenagel-related MCRs also become efficient strategies for achieving radical-scavengers. On the other hand, the Ugi 4CR and Passerini 3CR result in the dipeptide and α-acyloxycarboxamide, respectively, with the benefit for the integration of antioxidative features by aliphatic chains. Therefore, MCRs have emerged as efficient tools for integrating multiple antioxidative features into one molecule in order to meet with complicated requirements from various biological surroundings.

Phenethyl Esters and Amide of Ferulic Acid, Hydroferulic Acid, Homovanillic Acid, and Vanillic Acid: Synthesis, Free Radicals Scavenging Activity, and Molecular Modeling as Potential Cholinesterases Inhibitors

As ferulic acid was reported to be involved in novel potential mechanisms associated with Alzheimer’s disease (AD) therapy, five closely related phenethyl esters and amide of this natural product were synthesized and screened for their free radicals scavenging activity. Ferulic acid and its analogue′s absorption, distribution, metabolism, and excretion (ADME) properties were predicted. All compounds obey Lipinski′s rules. Moreover, all evaluated compounds seem to present a high oral bioavailability and blood–brain barrier (BBB) permeation which is crucial for Alzheimer′s disease drug candidates. Molecular docking of analogues 4 and 8 with acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) showed interactions with the residues of the catalytic triad of AChE and BChE. In addition to their interactions with the anionic subsite, hydroferulic acid phenethyl ester 4 and homovanillic acid phenethyl ester 8 may have potential as inhibitors of AChE and BChE, respectively.

Synthesis of new ferulic/lipoic/comenic acid-melatonin hybrids as antioxidants and Nrf2 activators via Ugi reaction

Aim: Oxidative stress has been implicated in the pathogenesis of many neurodegenerative diseases, and particularly in Alzheimer's disease. Results: This work describes the Ugi multicomponent synthesis, antioxidant power and Nrf2 pathway induction in antioxidant response element cells of (E)-N-(2-((2-(1H-indol-3-yl)ethyl)amino)-2-oxoethyl)-N-(2-(5-(benzyloxy)-1H-indol-3-yl)ethyl)-3-(4-hydroxy-3-methoxyphenyl)acryl amides 8a-d, N-(2-((2-(1H-indol-3-yl)ethyl)amino)-2-oxoethyl)-N-(2-(5-(benzyloxy)-1H-indol-3-yl)ethyl)-5-(1,2-dithiolan-3-yl)pentanamides 8e-h and N-(2-((2-(1H-indol-3-yl)ethyl)amino)-2-oxoethyl)-N-(2-(5-(benzyloxy)-1H-indol-3-yl)ethyl)-5-hydroxy-4-oxo-4H-pyran-2-carboxamides 8i,j. Conclusion: We have identified compounds 8e and 8g, showing a potent antioxidant capacity, a remarkable neuroprotective effect against the cell death induced by H₂O₂ in SH-SY5Y cells, and a performing activation of the Nrf2 signaling pathway, as very interesting new antioxidant agents for pathologies that curse with oxidative stress.

Novel anti-Alzheimer phenol-lipoyl hybrids: Synthesis, physico-chemical characterization, and biological evaluation

To date, drugs that hit a single target are inadequate for the treatment of neurodegenerative diseases, such as Alzheimer's or Parkinson's diseases. The development of multitarget ligands, able to interact with the different pathways involved in the progession of these disorders, represents a great challenge for medicinal chemists. In this context, we report here the synthesis and biological evaluation of phenol-lipoyl hybrids (SV1-13), obtained via a linking strategy, to take advantage of the synergistic effect due to the antioxidant portions and anti-amyloid properties of the single constituents present in the hybrid molecule. Biological results showed that SV5 and SV10 possessed the best protective activity against Aβ_1-42 induced neurotoxicity in differentiated SH-SY5Y cells. SV9 and SV10 showed remarkable antioxidant properties due to their ability to counteract the damage caused by H₂O₂ in SHSY-5Y-treated cells. Hovewer, SV5, showing moderate antioxidant and good neuroprotective activities, resulted the best candidate for further experiments since it also resulted stable both simulated and plasma fluids.