Alzheimer's Disease Pharmacotherapy in Relation to Cholinergic System Involvement

An update on the cognitive safety of antimuscarinics in the treatment of overactive bladder

INTRODUCTION

Antimuscarinics are often the first-choice medications used to treat overactive bladder (OAB), a condition that increasingly affects the aging population. However, concerns regarding their potential impact on cognitive function have persisted for more than a decade.

AREAS COVERED

This review was conducted to update the literature on the cognitive safety profiles of various antimuscarinics, integrating findings from both recent and earlier studies to present an updated and comprehensive analysis. A search of English-language publications, including electronic databases and gray literature, focused on the cognitive impacts of antimuscarinics, resulting in a review and assessment of diverse studies and their associated outcomes.

EXPERT OPINION

Oxybutynin requires caution due to potential adverse effects, suggesting a need to consider alternative therapies. Darifenacin, while promising in preserving cognitive function, warrants further investigation for use in dementia patients. Fesoterodine has shown tolerance without cognitive decline in controlled trials. However, Tolterodine and Solifenacin present conflicting evidence regarding cognitive impairment and dementia risk, respectively, necessitating additional research to ascertain their safety profiles. Careful monitoring and treatment of patients taking these medications for cognitive impairment are essential. Further research, particularly in vulnerable populations, is crucial to establish cognitive safety profiles of various antimuscarinics and inform optimal OAB treatment strategies.

Imidazole-thiadiazole hybrids: A multitarget de novo drug design approach, in vitro evaluation, ADME/T, and in silico studies

A library of imidazole-thiadiazole compounds (1-24) was synthesized to explore their therapeutic applications. The compounds were subjected to meticulous in vitro evaluation against α-glucosidase, α-amylase, acetylcholinesterase (AChE), and butylcholinesterase (BChE) enzymes. Compounds were also investigated for antioxidant activities using cupric reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays. Derivatives 5-7, 9-11, 18, and 19 displayed potent inhibitory activities with IC50 values of 1.4 ± 0.01 to 13.6 ± 0.01 and 0.9 ± 0.01 to 12.8 ± 0.02 µM against α-glucosidase, and α-amylase enzymes, respectively, compared to the standard acarbose (IC50 = 14.8 ± 0.01 µM). Compounds 11-13, 16, 20, and 21 exhibited potent activity IC50 = 8.6 ± 0.02 to 34.7 ± 0.03 µM against AChE enzyme, compared to donepezil chloride (IC50 = 39.2 ± 0.05 µM). Compound 21 demonstrated comparable inhibition IC50 = 45.1 ± 0.09 µM against BChE, compared to donepezil chloride (IC50 = 44.2 ± 0.05 µM). All compounds also demonstrated excellent antioxidant activities via CUPRAC, FRAP, and DPPH methods. Complementing the experimental studies, extensive kinetics, ADME/T, and molecular docking analysis were also conducted to unravel the pharmacokinetics and safety profiles of the designed compounds. These studies supported the experimental findings and facilitated the prioritization of hit candidates for subsequent stages of drug development.

Recent advances in Alzheimer's disease: Mechanisms, clinical trials and new drug development strategies

Alzheimer's disease (AD) stands as the predominant form of dementia, presenting significant and escalating global challenges. Its etiology is intricate and diverse, stemming from a combination of factors such as aging, genetics, and environment. Our current understanding of AD pathologies involves various hypotheses, such as the cholinergic, amyloid, tau protein, inflammatory, oxidative stress, metal ion, glutamate excitotoxicity, microbiota-gut-brain axis, and abnormal autophagy. Nonetheless, unraveling the interplay among these pathological aspects and pinpointing the primary initiators of AD require further elucidation and validation. In the past decades, most clinical drugs have been discontinued due to limited effectiveness or adverse effects. Presently, available drugs primarily offer symptomatic relief and often accompanied by undesirable side effects. However, recent approvals of aducanumab (1) and lecanemab (2) by the Food and Drug Administration (FDA) present the potential in disrease-modifying effects. Nevertheless, the long-term efficacy and safety of these drugs need further validation. Consequently, the quest for safer and more effective AD drugs persists as a formidable and pressing task. This review discusses the current understanding of AD pathogenesis, advances in diagnostic biomarkers, the latest updates of clinical trials, and emerging technologies for AD drug development. We highlight recent progress in the discovery of selective inhibitors, dual-target inhibitors, allosteric modulators, covalent inhibitors, proteolysis-targeting chimeras (PROTACs), and protein-protein interaction (PPI) modulators. Our goal is to provide insights into the prospective development and clinical application of novel AD drugs.

Characterization of Phenolic Profile and Biological Properties of Astragalus membranaceus Fisch. ex Bunge Commercial Samples

Astragalus membranaceus Fisch. ex Bunge (syn. Astragalus mongholicus Bunge) is one of the notable medicinal and food plants. Therefore, the aim of this study was to calculate the phenolic composition and antioxidant, antimicrobial, as well as enzyme inhibitory [acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase (TYR)] activities with chemometric approaches of the hydromethanolic and water extracts of commercial A. membranaceus samples. Ten individual phenolic compounds were determined using high-performance liquid chromatography (HPLC), and only quercetin was found at a level of above 80 µg/g DW in both extracts. Moreover, the highest antioxidant activity in DPPH, FRAP, ABTS, and CUPRAC assays was found in the sample containing the roots in loose form from USA. A. membranaceus extracts displayed the inhibition zone diameters within the range from 10 to 22 mm antimicrobial activity against S. aureus, while there were no inhibition zones in any extracts in case of E. coli. The extracts of A. membranaceous showed an inhibition rate below 40% against TYR, and among tested extracts, only two samples were able to inhibit BChE with IC50 values of above 30 µg/mL. Correlation analysis showed a highly positive relationship between their phenolic composition and antioxidant activity. Concluding, the obtained results confirmed that A. membranaceus commercial samples could be an important dietary source of natural antioxidants.

Proactive M2 blockade prevents cognitive decline in GRK5-deficient APP transgenic mice via enhancing cholinergic neuronal resilience

Alzheimer's disease (AD) poses an immense challenge in healthcare, lacking effective therapies. This study investigates the potential of anthranilamide derivative (AAD23), a selective M2 receptor antagonist, in proactively preventing cognitive impairments and cholinergic neuronal degeneration in G protein-coupled receptor kinase-5-deficient Swedish APP (GAP) mice. GAP mice manifest cognitive deficits by 7 months and develop senile plaques by 9 months. A 6-month AAD23 treatment was initiated at 5 months and stopped at 11 months before behavioral assessments without the treatment. AAD23-treated mice exhibited preserved cognitive abilities and improved cholinergic axonal health in the nucleus basalis of Meynert akin to wildtype mice. Conversely, vehicle-treated GAP mice displayed memory deficits and pronounced cholinergic axonal swellings in the nucleus basalis of Meynert. Notably, AAD23 treatment did not alter senile plaques and microgliosis. These findings highlight AAD23's efficacy in forestalling AD-related cognitive decline in G protein-coupled receptor kinase-5-deficient subjects, attributing its success to restoring cholinergic neuronal integrity and resilience, enhancing resistance against diverse degenerative insults.

An Expanded Narrative Review of Neurotransmitters on Alzheimer's Disease: The Role of Therapeutic Interventions on Neurotransmission

Alzheimer's disease (AD) is a progressive neurodegenerative disease. The accumulation of amyloid-β (Aβ) plaques and tau neurofibrillary tangles are the key players responsible for the pathogenesis of the disease. The accumulation of Aβ plaques and tau affect the balance in chemical neurotransmitters in the brain. Thus, the current review examined the role of neurotransmitters in the pathogenesis of Alzheimer's disease and discusses the alterations in the neurochemical activity and cross talk with their receptors and transporters. In the presence of Aβ plaques and neurofibrillary tangles, changes may occur in the expression of neuronal receptors which in turn triggers excessive release of glutamate into the synaptic cleft contributing to cell death and neuronal damage. The GABAergic system may also be affected by AD pathology in a similar way. In addition, decreased receptors in the cholinergic system and dysfunction in the dopamine neurotransmission of AD pathology may also contribute to the damage to cognitive function. Moreover, the presence of deficiencies in noradrenergic neurons within the locus coeruleus in AD suggests that noradrenergic stimulation could be useful in addressing its pathophysiology. The regulation of melatonin, known for its effectiveness in enhancing cognitive function and preventing Aβ accumulation, along with the involvement of the serotonergic system and histaminergic system in cognition and memory, becomes remarkable for promoting neurotransmission in AD. Additionally, nitric oxide and adenosine-based therapeutic approaches play a protective role in AD by preventing neuroinflammation. Overall, neurotransmitter-based therapeutic strategies emerge as pivotal for addressing neurotransmitter homeostasis and neurotransmission in the context of AD. This review discussed the potential for neurotransmitter-based drugs to be effective in slowing and correcting the neurodegenerative processes in AD by targeting the neurochemical imbalance in the brain. Therefore, neurotransmitter-based drugs could serve as a future therapeutic strategy to tackle AD.

Amelioration of Amyloid-β Induced Alzheimer's Disease by Bacopa monnieri through Modulation of Mitochondrial Dysfunction and GSK-3β/Wnt/β-Catenin Signaling

BACKGROUND

Alzheimer's disease (AD) is the most prevalent dementia, affecting a large number of populations. Despite being under scrutiny for decades, an effective therapeutic option is still not available.

METHODS AND RESULTS

This study explores the therapeutic role of a nootropic herb Bacopa monnieri (BM) in AD-like pathological conditions produced by injecting preformed amyloid-β42 (Aβ42) fibril bilaterally into hippocampus of Wistar rats, and ethanolic extract of BM is orally administered for 4 weeks. Assessment of behavioral changes reveals that BM treatment ameliorates Aβ42-induced cognitive impairment and compromised explorative behavior. Supplementation of BM also reduces oxidative stress biomarkers, proinflammatory cytokines, and cholinesterase activity in the AD rats. Additionally, BM treatment restores Bcl-2-associated X protein (Bax)/ B-cell lymphoma 2 (Bcl-2) imbalance, increases neurotrophic factors expression, and prevents neurodegeneration validated by quantifying Nissl-positive hippocampal neurons. Interestingly, BM administration eliminates amyloid plaques in the hippocampal region and normalizes the Aβ42-induced increase in phospho-tau and total tau expression. Mechanistic investigations reveal that BM interacts with glycogen synthase kinase (GSK-3β) and restores Wnt/β-catenin signaling.

CONCLUSION

BM has been used in diet as a nootropic herb for several centuries. This study highlights the anti-Alzheimer activity of BM from the behavioral to the molecular level by modulating mitochondrial dysfunction, and GSK-3β mediates the Wnt/β-catenin signaling pathway.

Study of multifunctional anti-AD ligands: design, synthesis, X-ray crystal structure and biological evaluation of diosmetin derivatives

The development of anti-AD drugs has attracted much attention as the number of AD patients is increasing year by year. Five diosmetin derivatives (1-5) were designed and synthesized by introducing carbamate groups. The crystal structure of 1 was analyzed by X-ray diffraction, which showed a large conjugated coplanar structure and might be favorable for the insertion into the Aβ folding. Meanwhile, in vitro experiments were carried out to investigate the anticholinesterase activity, metal chelating property, antioxidant activity, and anti-Aβ aggregation ability of 1-5. The results showed that 1-5 had good cholinesterase inhibitory activities. Compound 4 showed the highest inhibitory activities against butyrylcholinesterase (IC50 = 0.0760 μM). Further kinetic experiments and molecular docking studies showed that 4 could bind well to butyrylcholinesterase. The molecular dynamics simulations also signified that compared with diosmetin, 4 could reduce the flexibility of the butyrylcholinesterase protein skeleton to a greater extent, and thus had a better inhibitory effect. In addition, 1-5 could selectively chelate copper ions and all of them had good antioxidant activity as well as anti-Aβ aggregation ability. Among them, 4 had the strongest activity to inhibit Cu2+-induced Aβ aggregation (51.09%) and had low cytotoxicity. In addition, in vivo ROS activity assay (Caenorhabditis elegans) showed that 4 had the ability to scavenge ROS. Besides, the in vivo Aβ aggregation assay showed that 4 could reduce Aβ aggregation. In conclusion, 4 has the potential to be developed into a multifunctional anti-AD drug.

Mitochondrial One-Carbon Metabolism and Alzheimer's Disease

Mitochondrial one-carbon metabolism provides carbon units to several pathways, including nucleic acid synthesis, mitochondrial metabolism, amino acid metabolism, and methylation reactions. Late-onset Alzheimer's disease is the most common age-related neurodegenerative disease, characterised by impaired energy metabolism, and is potentially linked to mitochondrial bioenergetics. Here, we discuss the intersection between the molecular pathways linked to both mitochondrial one-carbon metabolism and Alzheimer's disease. We propose that enhancing one-carbon metabolism could promote the metabolic processes that help brain cells cope with Alzheimer's disease-related injuries. We also highlight potential therapeutic avenues to leverage one-carbon metabolism to delay Alzheimer's disease pathology.

Unveiling the neuroprotective properties of isoflavones: current evidence, molecular mechanisms and future perspectives

Neurodegenerative diseases encompass a wide range of debilitating and incurable brain disorders characterized by the progressive deterioration of the nervous system's structure and function. Isoflavones, which are naturally occurring polyphenolic phytochemicals, have been found to regulate various cellular signaling pathways associated with the nervous system. The main objective of this comprehensive review is to explore the neuroprotective effects of isoflavones, elucidate the underlying mechanisms, and assess their potential for treating neurodegenerative disorders. Relevant data regarding isoflavones and their impact on neurodegenerative diseases were gathered from multiple library databases and electronic sources, including PubMed, Google Scholar, Web of Science, and Science Direct. Numerous isoflavones, including genistein, daidzein, biochanin A, and formononetin, have exhibited potent neuroprotective properties against various neurodegenerative diseases. These compounds have been found to modulate neurotransmitters, which in turn contributes to their ability to protect against neurodegeneration. Both in vitro and in vivo experimental studies have provided evidence of their neuroprotection mechanisms, which involve interactions with estrogenic receptors, antioxidant effects, anti-inflammatory properties, anti-apoptotic activity, and modulation of neural plasticity. This review aims to provide current insights into the neuroprotective characteristics of isoflavones and shed light on their potential therapeutic applications in future clinical scenarios.

Passive Anti-Amyloid Beta Immunotherapies in Alzheimer's Disease: From Mechanisms to Therapeutic Impact

Alzheimer's disease, the most common type of dementia worldwide, lacks effective disease-modifying therapies despite significant research efforts. Passive anti-amyloid immunotherapies represent a promising avenue for Alzheimer's disease treatment by targeting the amyloid-beta peptide, a key pathological hallmark of the disease. This approach utilizes monoclonal antibodies designed to specifically bind amyloid beta, facilitating its clearance from the brain. This review offers an original and critical analysis of anti-amyloid immunotherapies by exploring several aspects. Firstly, the mechanisms of action of these therapies are reviewed, focusing on their ability to promote Aβ degradation and enhance its efflux from the central nervous system. Subsequently, the extensive history of clinical trials involving anti-amyloid antibodies is presented, from initial efforts using first-generation molecules leading to mixed results to recent clinically approved drugs. Along with undeniable progress, the authors also highlight the pitfalls of this approach to offer a balanced perspective on this topic. Finally, based on its potential and limitations, the future directions of this promising therapeutic strategy for Alzheimer's disease are emphasized.

Secondary metabolic profiling, antioxidant potential, enzyme inhibitory activities and in silico and ADME studies: a multifunctional approach to reveal medicinal and industrial potential of Tanacetum falconeri

Tanacetum falconeri is a significant flowering plant that possesses cytotoxic, insecticidal, antibacterial, and phytotoxic properties. Its chemodiversity and bioactivities, however, have not been thoroughly investigated. In this work, several extracts from various parts of T. falconeri were assessed for their chemical profile, antioxidant activity, and potential for enzyme inhibition. The total phenolic contents of T. falconeri varied from 40.28 ± 0.47 mg GAE/g to 11.92 ± 0.22 mg GAE/g in various extracts, while flavonoid contents were found highest in TFFM (36.79 ± 0.36 mg QE/g extract) and lowest (11.08 ± 0.22 mg QE/g extract) in TFSC (chloroform extract of stem) in similar pattern as found in total phenolic contents. Highest DPPH inhibition was observed for TFFC (49.58 ± 0.11 mg TE/g extract) and TFSM (46.33 ± 0.10 mg TE/g extract), whereas, TFSM was also potentially active against (98.95 ± 0.57 mg TE/g) ABTS radical. In addition, TFSM was also most active in metal reducing assays: CUPRAC (151.76 ± 1.59 mg TE/g extract) and FRAP (101.30 ± 0.32 mg TE/g extract). In phosphomolybdenum assay, the highest activity was found for TFFE (1.71 ± 0.03 mg TE/g extract), TFSM (1.64 ± 0.035 mg TE/g extract), TFSH (1.60 ± 0.033 mg TE/g extract) and TFFH (1.58 ± 0.08 mg TE/g extract), while highest metal chelating activity was recorded for TFSH (25.93 ± 0.79 mg EDTAE/g extract), TFSE (22.90 ± 1.12 mg EDTAE/g extract) and TFSC (19.31 ± 0.50 mg EDTAE/g extract). In biological screening, all extracts had stronger inhibitory capacity against AChE while in case of BChE the chloroform extract of flower (TFFC) and stem (TFSC) showed the highest activities with inhibitory values of 2.57 ± 0.24 and 2.10 ± 0.18 respectively. Similarly, TFFC and TFSC had stronger inhibitory capacity (1.09 ± 0.015 and 1.08 ± 0.002 mmol ACAE/g extract) against α-Amylase and (0.50 ± 0.02 and 0.55 ± 0.02 mmol ACAE/g extract) α-Glucosidase. UHPLC-MS study of methanolic extract revealed the presence of 133 components including sterols, triterpenes, flavonoids, alkaloids, and coumarins. The total phenolic contents were substantially linked with all antioxidant assays in multivariate analysis. These findings were validated by docking investigations, which revealed that the selected compounds exhibited high binding free energy with the enzymes tested. Finally, it was found that T. falconeri is a viable industrial crop with potential use in the production of functional goods and nutraceuticals.

L-Carnitine in the Treatment of Psychiatric and Neurological Manifestations: A Systematic Review

OBJECTIVE

L-carnitine (LC), a vital nutritional supplement, plays a crucial role in myocardial health and exhibits significant cardioprotective effects. LC, being the principal constituent of clinical-grade supplements, finds extensive application in the recovery and treatment of diverse cardiovascular and cerebrovascular disorders. However, controversies persist regarding the utilization of LC in nervous system diseases, with varying effects observed across numerous mental and neurological disorders. This article primarily aims to gather and analyze database information to comprehensively summarize the therapeutic potential of LC in patients suffering from nervous system diseases while providing valuable references for further research.

METHODS

A comprehensive search was conducted in PubMed, Web Of Science, Embase, Ovid Medline, Cochrane Library and Clinicaltrials.gov databases. The literature pertaining to the impact of LC supplementation on neurological or psychiatric disorders in patients was reviewed up until November 2023. No language or temporal restrictions were imposed on the search.

RESULTS

A total of 1479 articles were retrieved, and after the removal of duplicates through both automated and manual exclusion processes, 962 articles remained. Subsequently, a meticulous re-screening led to the identification of 60 relevant articles. Among these, there were 12 publications focusing on hepatic encephalopathy (HE), while neurodegenerative diseases (NDs) and peripheral nervous system diseases (PNSDs) were represented by 9 and 6 articles, respectively. Additionally, stroke was addressed in five publications, whereas Raynaud's syndrome (RS) and cognitive disorder (CD) each had three dedicated studies. Furthermore, migraine, depression, and amyotrophic lateral sclerosis (ALS) each accounted for two publications. Lastly, one article was found for other symptoms under investigation.

CONCLUSION

In summary, LC has demonstrated favorable therapeutic effects in the management of HE, Alzheimer's disease (AD), carpal tunnel syndrome (CTS), CD, migraine, neurofibromatosis (NF), PNSDs, RS, and stroke. However, its efficacy appears to be relatively limited in conditions such as ALS, ataxia, attention deficit hyperactivity disorder (ADHD), depression, chronic fatigue syndrome (CFS), Down syndrome (DS), and sciatica.

New curcumin-loaded nanocapsules as a therapeutic alternative in an amnesia model

This study aimed to investigate the action of two different formulations of curcumin (Cur)-loaded nanocapsules (Nc) (Eudragit [EUD] and poly (ɛ-caprolactone) [PCL]) in an amnesia mice model. We also investigated the formulations' effects on scopolamine-induced (SCO) depressive- and anxiety-like comorbidities, the cholinergic system, oxidative parameters, and inflammatory markers. Male Swiss mice were randomly divided into five groups (n = 8): group I (control), group II (Cur PCL Nc 10 mg/kg), group III (Cur EUD Nc 10 mg/kg), group IV (free Cur 10 mg/kg), and group V (SCO). Treatments with Nc or Cur (free) were performed daily or on alternate days. After 30 min of treatment, the animals received the SCO and were subjected to behavioral tests 30 min later (Barnes maze, open-field, object recognition, elevated plus maze, tail suspension tests, and step-down inhibitory avoidance tasks). The animals were then euthanized and tissue was removed for biochemical assays. Our results demonstrated that Cur treatment (Nc or free) protected against SCO-induced amnesia and depressive-like behavior. The ex vivo assays revealed lower acetylcholinesterase (AChE) and catalase (CAT) activity, reduced thiobarbituric species (TBARS), reactive species (RS), and non-protein thiols (NSPH) levels, and reduced interleukin-6 (IL-6) and tumor necrosis factor (TNF) expression. The treatments did not change hepatic markers in the plasma of mice. After treatments on alternate days, Cur Nc had a more significant effect than the free Cur protocol, implying that Cur may have prolonged action in Nc. This finding supports the concept that it is possible to achieve beneficial effects in nanoformulations, and treatment on alternate days differs from the free Cur protocol regarding anti-amnesic effects in mice.

Alzheimer's disease: In silico study of rosemary diterpenes activities

The global surge in Alzheimer's disease poses a significant public health concern. In response, we study the efficacy of carnosic acid and related abietane-type diterpenes extracted from rosemary as acetylcholinesterase (AChE) inhibitors. Our analyses, using in silico techniques, encompassed all the compounds within this extract. Through molecular docking, we explored how these compounds interact with the active site of the AChE protein. The docking scores, ranging from -5.560 Kcal/mol to -7.270 Kcal/mol, indicate robust binding affinities. Assessment of the ADME/T (Adsorption, Distribution, Metabolism, Excretion, and Toxicity) properties and pharmacokinetics of these compounds reveal favorable profiles for all the tested substances. These encouraging results suggest the potential of these compounds as candidates for further development to prevent and/or treat Alzheimer's disease. Among these compounds, we find rosmanol as the most likely candidate for further research and clinical trials to validate their efficacy.

A molecular container providing supramolecular protection against acetylcholine hydrolysis

Alzheimer's disease (AD) is characterized by cognitive decline, often attributed to the deficiency of acetylcholine, which can undergo hydrolysis by acetylcholinesterase (AChE) within the biological milieu. Here, we report a supramolecular strategy that takes advantage of confinement effects to inhibit such a hydrolysis process, shedding some light on AD therapy. A water-soluble and bowl-shaped molecule, hexacarboxylated tribenzotriquinacene (TBTQ-C6), was employed to shield acetylcholine (G1) from enzymatic degradation through host-guest binding interactions. Our study revealed highly efficient host-guest interactions with a binding ratio of 1 : 3, resulting in a significant reduction in acetylcholine hydrolysis from 91.1% to 7.4% in the presence of AChE under otherwise identical conditions. Furthermore, TBTQ-C6 showed potential for attenuating the degradation of butyrylcholine (G2) by butyrylcholinesterase (BChE). The broader implications of this study extend to the potential use of molecular containers in various biochemical and pharmacological applications, opening new avenues for research in the field of neurodegenerative diseases.

Electrochemical Acetylcholinesterase Sensors for Anti-Alzheimer's Disease Drug Determination

Neurodegenerative diseases and Alzheimer's disease (AD), as one of the most common causes of dementia, result in progressive losses of cholinergic neurons and a reduction in the presynaptic markers of the cholinergic system. These consequences can be compensated by the inhibition of acetylcholinesterase (AChE) followed by a decrease in the rate of acetylcholine hydrolysis. For this reason, anticholinesterase drugs with reversible inhibition effects are applied for the administration of neurodegenerative diseases. Their overdosage, variation in efficiency and recommendation of an individual daily dose require simple and reliable measurement devices capable of the assessment of the drug concentration in biological fluids and medications. In this review, the performance of electrochemical biosensors utilizing immobilized cholinesterases is considered to show their advantages and drawbacks in the determination of anticholinesterase drugs. In addition, common drugs applied in treating neurodegenerative diseases are briefly characterized. The immobilization of enzymes, nature of the signal recorded and its dependence on the transducer modification are considered and the analytical characteristics of appropriate biosensors are summarized for donepezil, huperzine A, rivastigmine, eserine and galantamine as common anti-dementia drugs. Finally, the prospects for the application of AChE-based biosensors in clinical practice are discussed.

Design and Synthesis of Pyrazole Carboxamide Derivatives as Selective Cholinesterase and Carbonic Anhydrase Inhibitors: Molecular Docking and Biological Evaluation

The present study focused on the synthesis and characterization of novel pyrazole carboxamide derivatives (SA1-12). The inhibitory effect of the compounds on cholinesterases (ChEs; AChE and BChE) and carbonic anhydrases (hCAs; hCA I and hCA II) isoenzymes were screened as in vitro. These series compounds have been identified as potential inhibitors with a KI values in the range of 10.69±1.27-70.87±8.11 nM for hCA I, 20.01±3.48-56.63±6.41 nM for hCA II, 6.60±0.62-14.15±1.09 nM for acetylcholinesterase (AChE) and 54.87±7.76-137.20 ±9.61 nM for butyrylcholinesterase (BChE). These compounds have a more effective inhibition effect when compared to the reference compounds. In addition, the potential binding positions of the compounds with high affinity for ChE and hCAs were demonstrated by in silico methods. The results of in silico and in vitro studies support each other. As a result of the present study, the compounds with high inhibitory activity for metabolic enzymes, such as ChE and hCA were designed. The compounds may be potential alternative agents used as selective ChE and hCA inhibitors in the treatment of Alzheimer's disease and glaucoma.

Choline metabolism in regulating inflammatory bowel disease-linked anxiety disorders: A multi-omics exploration of the gut-brain axis

Anxiety and depression caused by inflammatory bowel disease (IBD) negatively affect the mental health of patients. Emerging studies have demonstrated that the gut-brain axis (GBA) mediates IBD-induced mood disorders, but the underlying mechanisms of these findings remain unknown. Therefore, it's vital to conduct comprehensive research on the GBA in IBD. Multi-omics studies can provide an understanding of the pathological mechanisms of the GBA in the development of IBD, helping to uncover the mechanisms underlying the onset and progression of the disease. Thus, we analyzed the prefrontal cortex (PFC) of Dextran Sulfate Sodium Salt (DSS)-induced IBD mice using transcriptomics and metabolomics. We observed increased mRNA related to acetylcholine synthesis and secretion, along with decreased phosphatidylcholine (PC) levels in the PFC of DSS group compared to the control group. Fecal metagenomics also revealed abnormalities in the microbiome and lipid metabolism in the DSS group. Since both acetylcholine and PC are choline metabolites, we posited that the DSS group may experience choline deficiency and choline metabolism disorders. Subsequently, when we supplemented CDP-choline, IBD mice exhibited improvements, including decreased anxiety-like behaviors, reduced PC degradation, and increased acetylcholine synthesis in the PFC. In addition, administration of CDP-choline can restore imbalances in the gut microbiome and disruptions in lipid metabolism caused by DSS treatment. This study provides compelling evidence to suggest that choline metabolism plays a crucial role in the development and treatment of mood disorders in IBD. Choline and its metabolites appear to have a significant role in maintaining the stability of the GBA.

Alzheimer's Disease Puzzle: Delving into Pathogenesis Hypotheses

Alzheimer's disease (AD) is a prevalent neurodegenerative disease characterized by both amnestic and non-amnestic clinical manifestations. It accounts for approximately 60-70% of all dementia cases worldwide. With the increasing number of AD patients, elucidating underlying mechanisms and developing corresponding interventional strategies are necessary. Hypotheses about AD such as amyloid cascade, Tau hyper-phosphorylation, neuroinflammation, oxidative stress, mitochondrial dysfunction, cholinergic, and vascular hypotheses are not mutually exclusive, and all of them play a certain role in the development of AD. The amyloid cascade hypothesis is currently the most widely studied; however, other hypotheses are also gaining support. This article summarizes the recent evidence regarding major pathological hypotheses of AD and their potential interplay, as well as the strengths and weaknesses of each hypothesis and their implications for the development of effective treatments. This could stimulate further studies and promote the development of more effective therapeutic strategies for AD.

Green synthesis of zinc oxide nanoparticles using aqueous extract of shilajit and their anticancer activity against HeLa cells

In the present study, ZnO nanoparticles have been synthesized using an aqueous extract of shilajit. The nanoparticles were characterized using different techniques such as UV (ultraviolet-visible spectrophotometer), FTIR (Fourier transform infrared), XRD (X-ray diffraction), particle size analysis, SEM (scanning electron microscope) and EDAX (Energy-dispersive X-ray) analysis. The UV absorption peak at 422.40 nm was observed for ZnO nanoparticles. SEM analysis showed the shape of nanoparticles to be spherical, FTIR spectrum confirmed the presence of zinc atoms, particle size analysis showed the nanoparticle size, EDAX confirmed the purity of ZnO nanoparticles whereas XRD pattern similar to that of JCPDS card for ZnO confirmed the presence of pure ZnO nanoparticles. The in vitro anticancer activity of ZnO nanoparticles against the HeLa cell line showed the IC50 value of 38.60 μg/mL compared to reference standard cisplatin. This finding confirms that ZnO nanoparticles from shilajit extract have potent cytotoxic effect on human cervical cancer cell lines.

Assessing the potential of Psidium guajava derived phytoconstituents as anticholinesterase inhibitor to combat Alzheimer's disease: an in-silico and in-vitro approach

Acetylcholinesterase (AChE) inhibitors play a crucial role in the treatment of Alzheimer's disease. These drugs increase acetylcholine levels by inhibiting the enzyme responsible for its degradation, which is a vital neurotransmitter involved in memory and cognition. This intervention intermittently improves cognitive symptoms and augments neurotransmission. This study investigates the potential of Psidium guajava fruit extract as an acetylcholinesterase (AChE) inhibitor for Alzheimer's disease treatment. Molecular characteristics and drug-likeness were analyzed after HR-LCMS revealed phytocompounds in an ethanolic extract of Psidium guajava fruit. Selected phytocompounds were subjected to molecular docking against AChE, with the best-docked compound then undergoing MD simulation, MMGBSA, DCCM, FEL, and PCA investigations to evaluate the complex stability. The hit compound's potential toxicity and further pharmacokinetic features were also predicted. Anticholinesterase activity was also studied using in vitro assay. The HR-LCMS uncovered 68 compounds. Based on computational analysis, Fluspirilene was determined to have the highest potential to inhibit AChE. It was discovered that the Fluspirilene-AChE complex is stable and that Fluspirilene has a high binding affinity for AChE. Extract of Psidium guajava fruit significantly inhibits AChE (88.37% at 200 μg/ml). It is comparable to the standard AChE inhibitor Galantamine. Fluspirilene exhibited remarkable binding to AChE. Psidium guajava fruit extract demonstrated substantial AChE inhibitory activity, indicating its potential for Alzheimer's treatment. The study underscores natural sources' significance in drug discovery.Communicated by Ramaswamy H. Sarma.

Shark fish oil prevents scopolamine-induced memory impairment in an experimental model

Fish oil has been known for its antioxidant, cardioprotective, anti-inflammatory, and neuroprotective characteristics due to the presence of polyunsaturated fatty acids (PUFAs) that are essential for optimal brain function and mental health. The present study investigated the effect of Carcharhinus Bleekeri (Shark Fish) oil on learning and memory functions in scopolamine-induced amnesia in rats. Locomotor and memory-enhancing activity in scopolamine-induced amnesic rats was investigated by assessing the open field and passive avoidance paradigm. Forty male Albino mice were divided into 4 equal groups (n = 10) as bellow: 1 - control (received 0.9% saline), 2 - SCOP (received scopolamine 2 mg/kg for 21 days), 3 - SCOP + SFO (received scopolamine and fish oil 5 mg/kg/ day for 21 days), 4 - SCOP + Donepezil groups (received 3 mg/kg/day for 21 days). SFO produced significant (P < 0.01) locomotor and memory-enhancing activities in open-field and passive avoidance paradigm models. Additionally, SFO restored the Acetylcholine (ACh) concentration in the hippocampus (p < 0.05) and remarkably prevented the degradation of monoamines. Histology of brain tissue showed marked cellular distortion in the scopolamine-treated group, while the SFO treatment restored distortion in the brain's hippocampus region. These results suggest that the SFO significantly ameliorates scopolamine-induced spatial memory impairment by attenuating the ACh and monoamine concentrations in the rat's hippocampus.

Naturally Occurring Cholinesterase Inhibitors from Plants, Fungi, Algae, and Animals: A Review of the Most Effective Inhibitors Reported in 2012-2022

Since the development of the "cholinergic hypothesis" as an important therapeutic approach in the treatment of Alzheimer's disease (AD), the scientific community has made a remarkable effort to discover new and effective molecules with the ability to inhibit the enzyme acetylcholinesterase (AChE). The natural function of this enzyme is to catalyze the hydrolysis of the neurotransmitter acetylcholine in the brain. Thus, its inhibition increases the levels of this neurochemical and improves the cholinergic functions in patients with AD alleviating the symptoms of this neurological disorder. In recent years, attention has also been focused on the role of another enzyme, butyrylcholinesterase (BChE), mainly in the advanced stages of AD, transforming this enzyme into another target of interest in the search for new anticholinesterase agents. Over the past decades, Nature has proven to be a rich source of bioactive compounds relevant to the discovery of new molecules with potential applications in AD therapy. Bioprospecting of new cholinesterase inhibitors among natural products has led to the discovery of an important number of new AChE and BChE inhibitors that became potential lead compounds for the development of anti-AD drugs. This review summarizes a total of 260 active compounds from 142 studies which correspond to the most relevant (IC50 ≤ 15 μM) research work published during 2012-2022 on plant-derived anticholinesterase compounds, as well as several potent inhibitors obtained from other sources like fungi, algae, and animals.

Circular RNAs: Emerging Modulators in the Pathophysiology of Polycystic Ovary Syndrome and their Clinical Implications

Polycystic ovary syndrome (PCOS) is a prevalent endocrine/metabolic disorder in women of reproductive age. PCOS is characterized by hyperandrogenism, polycystic ovary morphology, and ovulatory dysfunction/anovulation. It involves multiple effects in patients, including granulosa/theca cell hyperplasia, menstrual disturbances, infertility, acne, obesity, insulin resistance, and cardiovascular disorders. Biochemical analyses and the results of RNA sequencing studies in recent years have shown a type of non-coding RNAs as a splicing product known as circular RNAs (circRNAs). Several biological functions have been identified in relation to circRNAs, including a role in miRNA sponge, protein sequestration, increased parental gene expression, and translation leading to polypeptides. These circular molecules are more plentiful and specialized than other types of RNAs. For this reason, they are referred to as potential biomarkers in different diseases. Evidence suggests that circRNAs may have regulatory potentials through different signaling pathways, such as the miRNA network. Probably most experts in the field of obstetricians are not aware of circRNAs as a useful biomarker. Therefore, this review focused on the researches that have been done on the involvement of circRNAs in PCOS and summarized recent supportive evidence, and evaluated the circRNA association and mechanisms involved in PCOS.

Carbamate as a potential anti-Alzheimer's pharmacophore: A review

Alzheimer's disease (AD) is a progressive age-related neurodegenerative brain disorder, which leads to loss of memory and other cognitive dysfunction. The underlying mechanisms of AD pathogenesis are very complex and still not fully explored. Cholinergic neuronal loss, accumulation of amyloid plaque, metal ions dyshomeostasis, tau hyperphosphorylation, oxidative stress, neuroinflammation, and mitochondrial dysfunction are major hallmarks of AD. The current treatment options for AD are acetylcholinesterase inhibitors (donepezil, rivastigmine, and galantamine) and NMDA receptor antagonists (memantine). These FDA-approved drugs mainly provide symptomatic relief without addressing the pathological aspects of disease progression. So, there is an urgent need for novel drug development that not only addresses the basic mechanisms of the disease but also shows the neuroprotective property. Various research groups across the globe are working on the development of multifunctional agents for AD amelioration using different core scaffolds for their design, and carbamate is among them. Rivastigmine was the first carbamate drug investigated for AD management. The carbamate fragment, a core scaffold of rivastigmine, act as a potential inhibitor of acetylcholinesterase. In this review, we summarize the last 10 years of research conducted on the modification of carbamate with different substituents which primarily target ChE inhibition, reduce oxidative stress, and modulate Aβ aggregation.

Preclinical Studies of Canagliflozin, a Sodium-Glucose Co-Transporter 2 Inhibitor, and Donepezil Combined Therapy in Alzheimer's Disease

The incidence of neurodegenerative diseases, such as Alzheimer's disease (AD), is continuously growing worldwide, which leads to a heavy economic and societal burden. The lack of a safe and effective causal therapy in cognitive decline is an aggravating factor and requires investigations into the repurposing of commonly used drugs. Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are a new and efficient class of hypoglycemic drugs and, due to their pleiotropic effects, have indications that go beyond diabetes. There is emerging data from murine studies that SGLT2i can cross the blood-brain barrier and may have neuroprotective effects, such as increasing the brain-derived neurotrophic factor (BDNF), reducing the amyloid burden, inhibiting acetylcholinesterase (AChE) and restoring the circadian rhythm in the mammalian target of rapamycin (mTOR) activation. The current study investigates the effect of an SGLT2i and donepezil, under a separate or combined 21-day treatment on AD-relevant behaviors and brain pathology in mice. The SGLT2i canagliflozin was found to significantly improve the novelty preference index and the percentage of time spent in the open arms of the maze in the novel object recognition and elevated plus maze test, respectively. In addition, canagliflozin therapy decreased AChE activity, mTOR and glial fibrillary acidic protein expression. The results also recorded the acetylcholine M1 receptor in canagliflozin-treated mice compared to the scopolamine group. In the hippocampus, the SGLT2i canagliflozin reduced the microgliosis and astrogliosis in males, but not in female mice. These findings emphasize the value of SGLT2i in clinical practice. By inhibiting AChE activity, canagliflozin represents a compound that resembles AD-registered therapies in this respect, supporting the need for further evaluation in dementia clinical trials.

The composition, pharmacological effects, related mechanisms and drug delivery of alkaloids from Corydalis yanhusuo

Corydalis yanhusuo W. T. Wang, also known as yanhusuo, yuanhu, yanhu and xuanhu, is one of the herb components of many Chinese Traditional Medicine prescriptions such as Jin Ling Zi San and Yuanhu-Zhitong priscription. C. yanhusuo was traditionally used to relieve pain and motivate blood and Qi circulation. Now there has been growing interest in pharmacological effects of alkaloids, the main bioactive components of C. yanhusuo. Eighty-four alkaloids isolated from C. yanhusuo are its important bioactive components and can be characterized into protoberberine alkaloids, aporphine alkaloids, opiate alkaloids and others and proper extraction or co-administration methods modulate their contents and efficacy. Alkaloids from C. yanhusuo have various pharmacological effects on the nervous system, cardiovascular system, cancer and others through multiple molecular mechanisms such as modulating neurotransmitters, ion channels, gut microbiota, HPA axis and signaling pathways and are potential treatments for many diseases. Plenty of novel drug delivery methods such as autologous red blood cells, self-microemulsifying drug delivery systems, nanoparticles and others have also been investigated to better exert the effects of alkaloids from C. yanhusuo. This review summarized the alkaloid components of C. yanhusuo, their pharmacological effects and mechanisms, and methods of drug delivery to lay a foundation for future investigations.

Pathophysiological Aspects and Therapeutic Armamentarium of Alzheimer's Disease: Recent Trends and Future Development

Alzheimer's disease (AD) is the primary cause of dementia and is characterized by the death of brain cells due to the accumulation of insoluble amyloid plaques, hyperphosphorylation of tau protein, and the formation of neurofibrillary tangles within the cells. AD is also associated with other pathologies such as neuroinflammation, dysfunction of synaptic connections and circuits, disorders in mitochondrial function and energy production, epigenetic changes, and abnormalities in the vascular system. Despite extensive research conducted over the last hundred years, little is established about what causes AD or how to effectively treat it. Given the severity of the disease and the increasing number of affected individuals, there is a critical need to discover effective medications for AD. The US Food and Drug Administration (FDA) has approved several new drug molecules for AD management since 2003, but these drugs only provide temporary relief of symptoms and do not address the underlying causes of the disease. Currently, available medications focus on correcting the neurotransmitter disruption observed in AD, including cholinesterase inhibitors and an antagonist of the N-methyl-D-aspartate (NMDA) receptor, which temporarily alleviates the signs of dementia but does not prevent or reverse the course of AD. Research towards disease-modifying AD treatments is currently underway, including gene therapy, lipid nanoparticles, and dendrimer-based therapy. These innovative approaches aim to target the underlying pathological processes of AD rather than just managing the symptoms. This review discusses the novel aspects of pathogenesis involved in the causation of AD of AD and in recent developments in the therapeutic armamentarium for the treatment of AD such as gene therapy, lipid nanoparticles, and dendrimer-based therapy, and many more.

Oxymatrine-mediated prevention of amyloid β-peptide-induced apoptosis on Alzheimer's model PC12 cells: in vitro cell culture studies and in vivo cognitive assessment in rats

Alzheimer's disease (AD) is a major neurological disease affecting elderly individuals worldwide. Existing drugs only reduce the symptoms of the disease without addressing the underlying causes. Commonly, Aβ25-35 peptide aggregation is the main reason for AD development. Recently, the discovery of multiple protein-targeting molecules has provided a new strategy for treating AD. This study demonstrates the neuroprotective potential of oxymatrine against multiple mechanisms, such as acetylcholinesterase, mitochondrial damage, and β-amyloid-induced cell toxicity. The in vitro cell culture studies showed that oxymatrine possesses significant potential to inhibit acetylcholine esterase and promotes antioxidant, antiapoptotic effects while preventing Aβ25-35 peptide aggregation in PC12 cells. Furthermore, oxymatrine protects PC12 cells against Aβ25-35-induced cytotoxicity and down-regulates the reactive oxygen species generation. The in vivo acute toxicological studies confirm the safety of oxymatrine without causing organ damage or death in animals. Overall, this study provided evidence that oxymatrine is an efficient neuroprotective agent, with a potential to be a multifunctional drug for Alzheimer's disease treatment. These findings present a reliable and synergistic approach for treating AD.

Physical Exercise as Disease-Modifying Alternative against Alzheimer's Disease: A Gut-Muscle-Brain Partnership

Alzheimer's disease (AD) is a common cause of dementia characterized by neurodegenerative dysregulations, cognitive impairments, and neuropsychiatric symptoms. Physical exercise (PE) has emerged as a powerful tool for reducing chronic inflammation, improving overall health, and preventing cognitive decline. The connection between the immune system, gut microbiota (GM), and neuroinflammation highlights the role of the gut-brain axis in maintaining brain health and preventing neurodegenerative diseases. Neglected so far, PE has beneficial effects on microbial composition and diversity, thus providing the potential to alleviate neurological symptoms. There is bidirectional communication between the gut and muscle, with GM diversity modulation and short-chain fatty acid (SCFA) production affecting muscle metabolism and preservation, and muscle activity/exercise in turn inducing significant changes in GM composition, functionality, diversity, and SCFA production. This gut-muscle and muscle-gut interplay can then modulate cognition. For instance, irisin, an exercise-induced myokine, promotes neuroplasticity and cognitive function through BDNF signaling. Irisin and muscle-generated BDNF may mediate the positive effects of physical activity against some aspects of AD pathophysiology through the interaction of exercise with the gut microbial ecosystem, neural plasticity, anti-inflammatory signaling pathways, and neurogenesis. Understanding gut-muscle-brain interconnections hold promise for developing strategies to promote brain health, fight age-associated cognitive decline, and improve muscle health and longevity.

In silico identification of novel heterocyclic compounds combats Alzheimer's disease through inhibition of butyrylcholinesterase enzymatic activity

Increasing evidence indicates that heterocyclic molecules possess properties against butyrylcholinesterase (BChE) enzymatic activity, which is a potential therapeutic target for Alzheimer's disease (AD). Thus, this study aimed to further evaluate the relationship between heterocyclic molecules and their biological activities. A dataset of 38 selective and potent heterocyclic compounds (-log[the half‑maximal inhibitory concentration (pIC50)]) values ranging from 8.02 to 10.05) was applied to construct a quantitative structure-activity relationship (QSAR) study, including Bayesian model average (BMA), artificial neural network (ANN), multiple nonlinear regression (MNLR), and multiple linear regression (MLR) models. Four models met statistical acceptance in internal and external validation. The ANN model was superior to other models in predicting the pIC50 of the outcome. The descriptors put into the models were found to be comparable with the target-ligand complex X-ray structures, making these models interpretable. Three selected molecules possess drug-like properties (pIC50 values ranged from 9.19 to 9.54). The docking score between candidates and the BChE receptor (RCSB ID 6EYF) ranged from -8.4 to -9.0 kcal/mol. Remarkably, the pharmacokinetics, biological activities, molecular dynamics, and physicochemical properties of compound 18 (C20H22N4O, pIC50 value = 9.33, oxadiazole derivative group) support its protective effects on AD treatment due to its non-toxic nature, non-carcinogen, cholinergic nature, capability to penetrate the blood-brain barrier, and high gastrointestinal absorption.Communicated by Ramaswamy H. Sarma.

Impact of Donepezil Supplementation on Alzheimer's Disease-like Pathology and Gut Microbiome in APP/PS1 Mice

Based on published information, the occurrence and development of Alzheimer's disease (AD) are potentially related to gut microbiota changes. Donepezil hydrochloride (DH), which enhances cholinergic activity by blocking acetylcholinesterase (AChE), is one of the first-line drugs for AD treatment approved by the Food and Drug Administration (FDA) of the USA. However, the potential link between the effects of DH on the pathophysiological processes of AD and the gut microbiota remains unclear. In this study, pathological changes in the brain and colon, the activities of superoxide dismutase (SOD) and AChE, and changes in intestinal flora were observed. The results showed that Aβ deposition in the prefrontal cortex and hippocampus of AD mice was significantly decreased, while colonic inflammation was significantly alleviated by DH treatment. Concomitantly, SOD activity was significantly improved, while AChE was significantly reduced after DH administration. In addition, the gut microbiota community composition of AD mice was significantly altered after DH treatment. The relative abundance of Akkermansia in the AD group was 54.8% higher than that in the N group. The relative abundance of Akkermansia was increased by 18.3% and 53.8% in the AD_G group and the N_G group, respectively. Interestingly, Akkermansia showed a potential predictive value and might be a biomarker for AD. Molecular docking revealed the binding mode and major forces between DH and membrane proteins of Akkermansia. The overall results suggest a novel therapeutic mechanism for treating AD and highlight the critical role of gut microbiota in AD pathology.

Exploring Concomitant Acetylcholinesterase Inhibitor and Overactive Bladder Anticholinergic Use and Risk of Hospitalization in Medicare and Dual-Eligible Medicare-Medicaid Populations in a Historic Database

Overactive bladder prevalence increases in older adults often complicating the management of other comorbidities. The theoretical antagonism between the parasympathetic-blocking anticholinergic agent and the parasympathetic stimulatory agents concomitantly used by patients is only recently being explored. The primary aim was to determine the frequency of the annual use of acetylcholinesterase inhibitors, overactive bladder anticholinergics, and the use of both agents in the same year. The secondary aim was measurement of the association between annual hospitalization and same-year use of both acetylcholinesterase inhibitors and anticholinergics. The US nationally representative MarketScan® Medicare databases were analyzed. In the Medicare enrollees, there were 122 020, 141 920, and 15 639 users of acetylcholinesterase inhibitors, anticholinergics, and both agents, respectively. The percentage of acetylcholinesterase inhibitor users who also used anticholinergics was 12.8%. Comparing users of both acetylcholinesterase inhibitors and anticholinergics to those using AChEI alone, 5 608 of the former experienced a hospitalization (35.9%) compared to 33 182 of the latter (31.2%). There was an increased risk of hospitalization for those using both acetylcholinesterase inhibitors and anticholinergics in the same year, with an odds ratio (OR) of 1.23 (95% CI, 1.19, 1.28). Clinicians should consider improved monitoring of the usage of both medications and clarify alternative regimens that avoid anticholinergics in at-risk older adults.

Neuroprotective, neurogenic, and anticholinergic evidence of Ganoderma lucidum cognitive effects: Crucial knowledge is still lacking

Ganoderma lucidum is a mushroom that has been widely used for centuries in Asian countries for its antiaging properties. It is popularly known as "Ling Zhi," "Reishi," and "Youngzhi," and because of its benefits, it is known as the "immortality mushroom." Pharmacological assays have revealed that G. lucidum ameliorates cognitive impairments through inhibition of β-amyloid and neurofibrillary tangle formation, antioxidant effect, reduction of inflammatory cytokine release and apoptosis, genic expression modulation, among other activities. Chemical investigations on G. lucidum have revealed the presence of metabolites such as triterpenes, which are the most explored in this field, as well as flavonoids, steroids, benzofurans, and alkaloids; in the literature, these have also been reported to have mnemonic activity. These properties of the mushroom make it a potential source of new drugs to prevent or reverse memory disorders, as actual medications are able to only alleviate some symptoms but are unable to stop the progress of cognitive impairments, with no impact on social, familiar, and personal relevance. In this review, we discuss the cognitive findings of G. lucidum reported in the literature, converging the proposed mechanisms through the several pathways that underlie memory and cognition processes. In addition, we highlight the gaps that deserve particular attention to support future studies.

Theophylline-based hybrids as acetylcholinesterase inhibitors endowed with anti-inflammatory activity: synthesis, bioevaluation, in silico and preliminary kinetic studies

In this study, we investigated the conjugation of theophylline with different compounds of natural origin hoping to construct new hybrids with dual activity against cholinergic and inflammatory pathways as potential agents for the treatment of Alzheimer's disease (AD). Out of 28 tested hybrids, two hybrids, acefylline-eugenol 6d and acefylline-isatin 19, were able to inhibit acetylcholinesterase (AChE) at low micromolar concentration displaying IC50 values of 1.8 and 3.3 μM, respectively, when compared to the galantamine standard AChE inhibitor. Moreover, the prepared hybrids exhibited a significant anti-inflammatory effect against lipopolysaccharide induced inflammation in RAW 264.7 and reduced nitric oxide (NO), tumor necrosis alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) levels in a dose dependent manner. These hybrids demonstrated significant reductions in nitric oxide (NO), tumor necrosis alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) levels in RAW 264.7 cells induced by lipopolysaccharide (LPS). The findings of this study were further explained in light of network pharmacology analysis which suggested that AChE and nitric oxide synthase were the main targets of the most active compounds. Molecular docking studies revealed their ability to bind to the heme binding site of nitric oxide synthase 3 (NOS-3) and effectively occupy the active site of AChE, interacting with both the peripheral aromatic subsite and catalytic triad. Finally, the compounds demonstrated stability in simulated gastric and intestinal environments, suggesting potential absorption into the bloodstream without significant hydrolysis. These findings highlight the possible therapeutic potential of acefylline-eugenol 6d and acefylline-isatin 19 hybrids in targeting multiple pathological mechanisms involved in AD, offering promising avenues for further development as potential treatments for this devastating disease.

Differences in pharmacologic and demographic factors in male and female patients with vascular dementia, Alzheimer's disease, and mixed vascular dementia

Background

Increasing evidence suggests that demographic and pharmacologic factors may play a significant role in the epidemiology of dementia. Sex differences in prevalence also depend on dementia subtypes, such as Alzheimer's dementia (AD), vascular dementia (VaD), and mixed vascular-Alzheimer's dementia (MVAD). Therefore, studies are needed to investigate sex-specific differences, and identify potential therapeutic targets for both sexes.

Methods

Data was collected from the Prisma Health-Upstate Alzheimer's registry from 2016 to 2021 for 6,039 VaD patients, 9,290 AD patients, and 412 MVAD patients. A logistic regression was used to determine demographic and pharmacological factors associated with gender differences in patients with VaD, AD, and MVAD.

Results

In patients with VaD, African Americans (OR = 1.454, 95% CI, 1.257-1.682, p < 0.001) with increasing age (OR = 1.023, 95% CI, 1.017-1.029, p < 0.001), treated with aripiprazole (OR = 4.395, 95% CI, 2.880-6.707, p < 0.001), were associated with females, whereas patients treated with galantamine (OR = 0.228, 95% CI, 0.116-0.449, p < 0.001), memantine (OR = 0.662, 95% CI, 0.590-0.744, p < 0.001), with a history of tobacco (OR = 0.312, 95% CI, 0.278-0.349, p < 0.001), and ETOH (OR = 0.520, 95% CI, 0.452-0.598, p < 0.001) were associated with males. Among AD patients, African Americans (OR = 1.747, 95% CI, 1.486-2.053, p < 0.001), and Hispanics (OR = 3.668, 95% CI, 1.198-11.231, P = 0.023) treated with buspirone (OR = 1.541, 95% CI, 1.265-1.878, p < 0.001), and citalopram (OR = 1.790, 95% CI, 1.527-2.099, p < 0.001), were associated with females, whereas patients treated with memantine (OR = 0.882, 95% CI, 0.799-0.974, p = 0.013), and with a history of tobacco (OR = 0.247, 95% CI, 0.224-0.273, p < 0.001), and ETOH (OR = 0.627, 95% CI, 0.547-0.718, p < 0.001) were associated with male AD patients. In patients with MVAD, rivastigmine (OR = 3.293, 95% CI, 1.131-9.585, p = 0.029), memantine (OR = 2.816, 95% CI, 1.534-5.168, p < 0.001), and risperidone (OR = 10.515, 95% CI, 3.409-32.437, p < 0.001), were associated with females while patients with an increased length of stay (OR = 0.910, 95% CI, 0.828-1.000, p = 0.049), with a history of tobacco (OR = 0.148, 95% CI, 0.086-0.254, p < 0.001) and ETOH use (OR = 0.229, 95% CI, 0.110-0.477, p < 0.001) were more likely to be associated with males.

Conclusions

Our study revealed gender differences and similarities in the demographic and pharmacological factors of VaD, AD, and MVAD. Prospective studies are needed to determine the role of demographic and pharmacological factors in reducing sex-based disparities among VaD, AD, and MVAD patients.

Apolipoprotein E ε4 triggers neurotoxicity via cholesterol accumulation, acetylcholine dyshomeostasis, and PKCε mislocalization in cholinergic neuronal cells

The Apolipoprotein E (ApoE) has been known to regulate cholesterol and β-amyloid (Aβ) production, redistribution, and elimination, in the central nervous system (CNS). The ApoE ε4 polymorphic variant leads to impaired brain cholesterol homeostasis and amyloidogenic pathway, thus representing the major risk factor for Alzheimer's Disease (AD). Currently, less is known about the molecular mechanisms connecting ApoE ε4-related cholesterol metabolism and cholinergic system degeneration, one of the main AD pathological features. Herein, in vitro cholinergic neuron models were developed in order to study ApoE neuronal expression and investigate the possible interplay between cholesterol metabolism and cholinergic pathway impairment prompted by ε4 isoform. Particularly, alterations specifically occurring in ApoE ε4-carrying neurons (i.e. increased intracellular ApoE, amyloid precursor protein (APP), and Aβ levels, elevated apoptosis, and reduced cell survival) were recapitulated. ApoE ε4 expression was found to increase intracellular cholesterol accumulation, by regulating the related gene expression, while reducing cholesterol precursor acetyl-CoA, which in turn fuels the acetylcholine (ACh) synthesis route. In parallel, although the ACh intracellular signalling was activated, as demonstrated by the boosted extracellular ACh as well as increased IP₃ and Ca²⁺, the PKCε activation via membrane translocation was surprisingly suppressed, probably explained by the cholesterol overload in ApoE ε4 neuron-like cells. Consequently, the PKC-dependent anti-apoptotic and neuroprotective roles results impaired, reliably adding to other causes of cell death prompted by ApoE ε4. Overall, the obtained data open the way to further critical considerations of ApoE ε4-dependent cholesterol metabolism dysregulation in the alteration of cholinergic pathway, neurotoxicity, and neuronal death.

Direct Enhancement Effect of Hippocampal Cholinergic Neurostimulating Peptide on Cholinergic Activity in the Hippocampus

The cholinergic efferent network from the medial septal nucleus to the hippocampus is crucial for learning and memory. This study aimed to clarify whether hippocampal cholinergic neurostimulating peptide (HCNP) has a rescue function in the cholinergic dysfunction of HCNP precursor protein (HCNP-pp) conditional knockout (cKO). Chemically synthesized HCNP or a vehicle were continuously administered into the cerebral ventricle of HCNP-pp cKO mice and littermate floxed (control) mice for two weeks via osmotic pumps. We immunohistochemically measured the cholinergic axon volume in the stratum oriens and functionally evaluated the local field potential in the CA1. Furthermore, choline acetyltransferase (ChAT) and nerve growth factor (NGF) receptor (TrkA and p75NTR) abundances were quantified in wild-type (WT) mice administered HCNP or the vehicle. As a result, HCNP administration morphologically increased the cholinergic axonal volume and electrophysiological theta power in HCNP-pp cKO and control mice. Following the administration of HCNP to WT mice, TrkA and p75NTR levels also decreased significantly. These data suggest that extrinsic HCNP may compensate for the reduced cholinergic axonal volume and theta power in HCNP-pp cKO mice. HCNP may function complementarily to NGF in the cholinergic network in vivo. HCNP may represent a therapeutic candidate for neurological diseases with cholinergic dysfunction, e.g., Alzheimer's disease and Lewy body dementia.

Synthesis, crystal structure, spectroscopic and computational investigations of the newly synthesized Schiff bases scaffold as enzyme inhibitor

The current project was planned to access the enzyme inhibition potential of the synthesize imines; (E)-2-(2-hydroxy-4,5-dimethoxybenzylideneamino)benzonitrile 1 and (E)-2-(((3-hydroxy-4-methylphenyl)imino)methyl)-4-methoxyphenol 2 by the reported protocol of our continuous research and also assess their theoretical function in term of in silico action. The structural characterization of imines was done through advanced techniques i.e., FTIR, ¹H NMR, ¹³C NMR, and UV spectroscopy. Moreover, a single X-Ray diffraction technique (SCXRD) was employed for real structural identification of imines dimensions, which revealed that compound 1 has a triclinic crystal system although 2 has a monoclinic one. A 2D fingerprint plot and Hirshfeld surface analysis (HS) was employed in the crystalline assembly of compounds to check intermolecular contacts and also their degree of contributions. Both compounds were optimized by B3LYP functional mode using a certain basis set (6-31G). The practical data (XRD) and theoretical data (DFT) of both molecules were compared and found between a sound coherence. Molecular docking studies in term of in silico assessment were conducted against enzymes of the esterase and alpha-glucosidase family. The docking outputs give a forecast about compounds that could be employed as protein inhibitors against analyzed protein surfaces.

Neuroprotective Role of DPP-4 Inhibitor Linagliptin Against Neurodegeneration, Neuronal Insulin Resistance and Neuroinflammation Induced by Intracerebroventricular Streptozotocin in Rat Model of Alzheimer's Disease

Alzheimer's disease (AD) is an age-related, multifactorial progressive neurodegenerative disorder manifested by cognitive impairment and neuronal death in the brain areas like hippocampus, yet the precise neuropathology of AD is still unclear. Continuous failure of various clinical trial studies demands the utmost need to explore more therapeutic targets against AD. Type 2 Diabetes Mellitus and neuronal insulin resistance due to serine phosphorylation of Insulin Receptor Substrate-1 at 307 exhibits correlation with AD. Dipeptidyl Peptidase-4 inhibitors (DPP-4i) have also indicated therapeutic effects in AD by increasing the level of Glucagon-like peptide-1 in the brain after crossing Blood Brain Barrier. The present study is hypothesized to examine Linagliptin, a DPP-4i in intracerebroventricular streptozotocin induced neurodegeneration, and neuroinflammation and hippocampal insulin resistance in rat model of AD. Following infusion on 1st and 3rd day, animals were treated orally with Linagliptin (0.513 mg/kg, 3 mg/kg, and 5 mg/kg) and donepezil (5 mg/kg) as a standard for 8 weeks. Neurobehavioral, biochemical and histopathological analysis was done at the end of treatment. Dose-dependently Linagliptin significantly reversed behavioral alterations done through locomotor activity (LA) and morris water maze (MWM) test. Moreover, Linagliptin augmented hippocampal GLP-1 and Akt-ser473 level and mitigated soluble Aβ (1-42), IRS-1 (s307), GSK-3β, TNF-α, IL-1β, IL-6, AchE and oxidative/nitrosative stress level. Histopathological analysis also exhibited neuroprotective and anti-amylodogenic effect in Hematoxylin and eosin and Congo red staining respectively. The findings of our study concludes remarkable dose-dependent therapeutic potential of Linagliptin against neuronal insulin resistance via IRS-1 and AD-related complication. Thus, demonstrates unique molecular mechanism that underlie AD.

Identification of promising inhibitory heterocyclic compounds against acetylcholinesterase using QSAR, ADMET, biological activity, and molecular docking

Heterocyclic compounds exert diverse functions, especially acetylcholinesterase (AChE) inhibition. Thus, identifying the association between their detailed structures and biological activities is important to the development of novel medications for Alzheimer's disease (AD) treatment. In this study, diverse sets of 120 potent and selective heterocyclic compounds (-log[the half‑maximal inhibitory concentration] (pIC50) values ranged from 8.01 to 12.50) were used to develop quantitative structure-activity relationship (QSAR) models using multiple linear regression (MLR), multiple nonlinear regression (MNLR), Bayesian model average (BMA), and artificial neural network (ANN) models. The models' robustness and stability have been assessed using both internal and external methodology. ANN outperforms MLR, MNLR, and BMA according to external validation. The molecular descriptors incorporated into the model were in satisfactory correlation with the AChE receptor-ligand complex X-ray structures, making the model interpretable and predictive. Three selected compounds exert drug-like characteristics (pIC50 values ranged from 11.01 to 11.17). The binding affinity between the optimal compounds and the AChE receptor (RCSB ID 3LII) ranged from - 7.4 to - 8.8 kcal/mol. Remarkably, the pharmacokinetics, physicochemical properties, and biological activities of compound 25 (C23H32N2O2, PubChem CID 118727071, pIC50 value = 11.17) were found to be consistent with its therapeutic effects in AD due to its cholinergic and non-toxic nature, non-P-glycoprotein, high gastrointestinal absorption, and capability to penetrate the blood-brain barrier.

Recent Development in the Understanding of Molecular and Cellular Mechanisms Underlying the Etiopathogenesis of Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that leads to dementia and patient death. AD is characterized by intracellular neurofibrillary tangles, extracellular amyloid beta (Aβ) plaque deposition, and neurodegeneration. Diverse alterations have been associated with AD progression, including genetic mutations, neuroinflammation, blood-brain barrier (BBB) impairment, mitochondrial dysfunction, oxidative stress, and metal ion imbalance.Additionally, recent studies have shown an association between altered heme metabolism and AD. Unfortunately, decades of research and drug development have not produced any effective treatments for AD. Therefore, understanding the cellular and molecular mechanisms underlying AD pathology and identifying potential therapeutic targets are crucial for AD drug development. This review discusses the most common alterations associated with AD and promising therapeutic targets for AD drug discovery. Furthermore, it highlights the role of heme in AD development and summarizes mathematical models of AD, including a stochastic mathematical model of AD and mathematical models of the effect of Aβ on AD. We also summarize the potential treatment strategies that these models can offer in clinical trials.

Activators of Nrf2 to Counteract Neurodegenerative Diseases

Neurodegenerative diseases are incurable and debilitating conditions that result in progressive degeneration and loss of nerve cells. Oxidative stress has been proposed as one factor that plays a potential role in the pathogenesis of neurodegenerative disorders since neuron cells are particularly vulnerable to oxidative damage. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is strictly related to anti-inflammatory and antioxidative cell response; therefore, its activation and the consequent enhancement of the related cellular pathways have been proposed as a potential therapeutic approach. Several Nrf2 activators with different mechanisms and diverse structures have been reported, but those applied for neurodisorders are still limited. However, in the very last few years, interesting progress has been made, particularly in enhancing the blood-brain barrier penetration, to make Nrf2 activators effective drugs, and in designing Nrf2-based multitarget-directed ligands to affect multiple pathways involved in the pathology of neurodegenerative diseases. The present review gives an overview of the most representative findings in this research area.

G, Krishnamurthy S, Chaurasia RN, Shrivastava SK. Development and Evaluation of Some Molecular Hybrids of N-(1-Benzylpiperidin-4-yl)-2-((5-phenyl-1,3,4-oxadiazol-2-yl)thio) as Multifunctional Agents to Combat Alzheimer's Disease

A series of some novel compounds (SD-1-17) were designed following a molecular hybridization approach, synthesized, and biologically tested for hAChE, hBChE, hBACE-1, and Aβ aggregation inhibition potential to improve cognition and memory functions associated with Alzheimer's disease. Compounds SD-4 and SD-6 have shown multifunctional inhibitory profiles against hAChE, hBChE, and hBACE-1 enzymes in vitro. Compounds SD-4 and SD-6 have also shown anti-Aβ aggregation potential in self- and acetylcholinesterase (AChE)-induced thioflavin T assay. Both compounds have shown a significant propidium iodide (PI) displacement from the cholinesterase-peripheral active site (ChE-PAS) region with excellent blood-brain barrier (BBB) permeability and devoid of neurotoxic liabilities. Compound SD-6 ameliorates cognition and memory functions in scopolamine- and Aβ-induced behavioral rat models of Alzheimer's disease (AD). Ex vivo biochemical estimation revealed a significant decrease in malonaldehyde (MDA) and AChE levels, while a substantial increase of superoxide dismutase (SOD), catalase, glutathione (GSH), and ACh levels is seen in the hippocampal brain homogenates. The histopathological examination of brain slices also revealed no sign of neuronal or any tissue damage in the SD-6-treated experimental animals. The in silico molecular docking results of compounds SD-4 and SD-6 showed their binding with hChE-catalytic anionic site (CAS), PAS, and the catalytic dyad residues of the hBACE-1 enzymes. A 100 ns molecular dynamic simulation study of both compounds with ChE and hBACE-1 enzymes also confirmed the ligand-protein complex's stability, while quikprop analysis suggested drug-like properties of the compounds.

Discovery of new, highly potent and selective inhibitors of BuChE - design, synthesis, in vitro and in vivo evaluation and crystallography studies

The symptomatic and disease-modifying effects of butyrylcholinesterase (BuChE) inhibitors provide an encouraging premise for researching effective treatments for Alzheimer's disease. Here, we examined a series of compounds with a new chemical scaffold based on 3-(cyclohexylmethyl)amino-2-hydroxypropyl, and we identified a highly selective hBuChE inhibitor (29). Based on extensive in vitro and in vivo evaluations of the compound and its enantiomers, (R)-29 was identified as a promising candidate for further development. Compound (R)-29 is a potent hBuChE inhibitor (IC₅₀ = 40 nM) with selectivity over AChE and relevant off-targets, including H₁, M₁, α_1A and β₁ receptors. The compound displays high metabolic stability on human liver microsomes (90% of the parent compound after 2 h of incubation), and its safety was confirmed through examining the cytotoxicity on the HepG2 cell line (LC₅₀ = 2.85 μM) and hERG inhibition (less than 50% at 10 μM). While (rac)-29 lacked an effect in vivo and showed limited penetration to the CNS in pharmacokinetics studies, compound (R)-29 exhibited a procognitive effect at 15 mg/kg in the passive avoidance task in scopolamine-treated mice.

Amorphous System of Hesperetin and Piperine-Improvement of Apparent Solubility, Permeability, and Biological Activities

The low bioaccessibility of hesperetin and piperine hampers their application as therapeutic agents. Piperine has the ability to improve the bioavailability of many compounds when co-administered. The aim of this paper was to prepare and characterize the amorphous dispersions of hesperetin and piperine, which could help to improve solubility and boost the bioavailability of both plant-origin active compounds. The amorphous systems were successfully obtained by means of ball milling, as confirmed by XRPD and DSC studies. What's more, the FT-IR-ATR study was used to investigate the presence of intermolecular interactions between the systems' components. Amorphization enhanced the dissolution rate as a supersaturation state was reached, as well as improving the apparent solubility of both compounds by 245-fold and 183-fold, respectively, for hesperetin and piperine. In the in vitro permeability studies simulating gastrointestinal tract and blood-brain barrier permeabilities, these increased by 775-fold and 257-fold for hesperetin, whereas they were 68-fold and 66-fold for piperine in the GIT and BBB PAMPA models, respectively. Enhanced solubility had an advantageous impact on antioxidant as well as anti-butyrylcholinesterase activities-the best system inhibited 90.62 ± 0.58% of DPPH radicals and 87.57 ± 1.02% butyrylcholinesterase activity. To sum up, amorphization considerably improved the dissolution rate, apparent solubility, permeability, and biological activities of hesperetin and piperine.

Action of the Purinergic and Cholinergic Anti-inflammatory Pathways on Oxidative Stress in Patients with Alzheimer's Disease in the Context of the COVID-19 Pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent of the 2019 coronavirus disease (COVID-19), has affected more than 20 million people in Brazil and caused a global health emergency. This virus has the potential to affect various parts of the body and compromise metabolic functions. The virus-mediated neural inflammation of the nervous system is due to a storm of cytokines and oxidative stress, which are the clinical features of Alzheimer's disease (AD). This neurodegenerative disease is aggravated in cases involving SARS-CoV-2 and its inflammatory biomarkers, accelerating accumulation of β-amyloid peptide, hyperphosphorylation of tau protein, and production of reactive oxygen species, which lead to homeostasis imbalance. The cholinergic system, through neurons and the neurotransmitter acetylcholine (ACh), modulates various physiological pathways, such as the response to stress, sleep and wakefulness, sensory information, and the cognitive system. Patients with AD have low concentrations of ACh; hence, therapeutic methods are aimed at adjusting the ACh titers available to the body for maintaining functionality. Herein, we focused on acetylcholinesterase inhibitors, responsible for the degradation of ACh in the synaptic cleft, and muscarinic and nicotinic receptor agonists of the cholinergic system owing to the therapeutic potential of the cholinergic anti-inflammatory pathway in AD associated with SARS-CoV-2 infection.

Effect of sulfonamide derivatives of phenylglycine on scopolamine-induced amnesia in rats

Alzheimer's disease is a neurodegenerative disease responsible for dementia and other neuropsychiatric symptoms. In the present study, compounds 30 and 33, developed earlier in our laboratory as selective butyrylcholinesterase inhibitors, were tested against scopolamine-induced amnesia to evaluate their pharmacodynamic effect. The efficacy of the compounds was determined by behavioral experiments using the Y-maze and the Barnes maze and neurochemical testing. Both compounds reduced the effect of scopolamine treatment in the behavioral tasks at a dose of 20 mg/kg. The results of the neurochemical experiment indicated a reduction in cholinesterase activity in the prefrontal cortex and the hippocampus. The levels of antioxidant enzymes superoxide dismutase and catalase were restored compared to the scopolamine-treated groups. The docking study on rat butyrylcholinesterase (BChE) indicated tight binding, with free energies of -9.66 and -10.23 kcal/mol for compounds 30 and 33, respectively. The two aromatic amide derivatives of 2-phenyl-2-(phenylsulfonamido) acetic acid produced stable complexes with rat BChE in the molecular dynamics investigation.

Pathogenesis of Chronic Kidney Disease Is Closely Bound up with Alzheimer's Disease, Especially via the Renin-Angiotensin System

Chronic kidney disease (CKD) is a clinical syndrome secondary to the definitive change in function and structure of the kidney, which is characterized by its irreversibility and slow and progressive evolution. Alzheimer's disease (AD) is characterized by the extracellular accumulation of misfolded β-amyloid (Aβ) proteins into senile plaques and the formation of neurofibrillary tangles (NFTs) containing hyperphosphorylated tau. In the aging population, CKD and AD are growing problems. CKD patients are prone to cognitive decline and AD. However, the connection between CKD and AD is still unclear. In this review, we take the lead in showing that the development of the pathophysiology of CKD may also cause or exacerbate AD, especially the renin-angiotensin system (RAS). In vivo studies had already shown that the increased expression of angiotensin-converting enzyme (ACE) produces a positive effect in aggravating AD, but ACE inhibitors (ACEIs) have protective effects against AD. Among the possible association of risk factors in CKD and AD, we mainly discuss the RAS in the systemic circulation and the brain.