Acetylcholinesterase Inhibitors Research Articles

New and Emerging Biological Therapies for Myasthenia Gravis: A Focussed Review for Clinical Decision-Making.

Myasthenia gravis (MG) is a rare autoimmune disease characterised by exertion-induced muscle weakness that can lead to potentially life-threatening myasthenic crises. Detectable antibodies are directed against specific postsynaptic structures of the neuromuscular junction. MG is a chronic condition that can be improved through therapies, but to date, not cured. Standard treatment has been unchanged for decades and includes symptomatic treatment with acetylcholine-esterase inhibitors and disease-modifying treatment with steroids, steroid-sparing immunosuppressants and thymectomy. Overall, a relevant proportion of patients does not achieve a satisfactory clinical improvement under standard treatment. Additionally, long-term therapy with steroids can cause significant side effects and latency to clinical improvement with standard steroid-sparing immunosuppressants and after thymectomy can take months to years. In recent years, treatment of MG has changed fundamentally due to improved evidence from phase 3 trials and the regulatory approval of complement inhibitors and FcRn inhibitors as add-on treatment options. This provides new optimism for substantially more patients reaching minimal manifestation status and has led to a shift in treatment strategy with more targeted therapies being employed early in the course of the disease, especially in patients with high disease activity. In this focussed review, we provide an overview of the diagnosis, classification and standard treatment of MG, followed by data from randomised controlled trials on the modern drugs already available for therapy and those still in the final stages of clinical development. In the second part, we provide an overview of real-world data for already approved therapies and outline how the availability of new biologicals is changing both clinical decision-making and patient journey.

Evaluation of developmental toxicity of chlorpyrifos through new approach methodologies: a systematic review.

Chlorpyrifos (CPF) is an organophosphorus pesticide of concern because many in vivo animal studies have demonstrated developmental toxicity exerted by this substance; however, despite its widespread use, evidence from epidemiological studies is still limited. In this study, we have collected all the information generated in the twenty-first century on the developmental toxicity of CPF using new approach methodologies. We have critically evaluated and integrated information coming from 70 papers considering human, rodent, avian and fish models. The comparison of the collected evidence with available adverse outcome pathways allows us to conclude that adverse outcomes observed in animals, such as memory and learning impairments as well as reduction in cognitive function, could involve several mechanisms of action including inhibition of acetylcholinesterase, overactivation of glutamate receptors and activation of mitogen-activated protein kinase, extracellular signal-regulated kinase 1/2, followed by both disruption of neurotransmitter release and increase in oxidative stress and apoptosis.

IN SILICO AND IN VITRO ASSESSMENT OF ANTI-Leishmania infantum ACTIVITY OF A NOVEL CYCLOHEXYL-1,2,4-OXADIAZOLE DERIVATIVE.

Globally, an estimated 1 billion people reside in endemic areas, and over 12 million individuals are infected with leishmaniasis. Despite its prevalence, leishmaniasis continues to be a neglected disease, mainly affecting underdeveloped countries. In Brazil, the available treatments are pentavalent antimonials and Amphotericin B, which are outdated, toxic, require prolonged parenteral administration and have limited efficacy. The heterocyclic ring oxadiazole has been documented in the literature to possess various biological activities, including leishmanicidal properties, thus positioning it as a potential candidate for further investigation. This study aims to evaluate the in vitro leishmanicidal activity of an oxadiazole compound (2i), explore its mechanism of action through enzymatic inhibition and molecular docking, assess its antioxidant activity, and conduct an in silico pharmacokinetic prediction. Pharmacokinetic predictions via ADME/TOX modeling revealed that the 2i molecule exhibits good intestinal absorption (92%), is water-insoluble (-4 log.mol/L) and demonstrates high permeability in Caco-2 cells (1.35log.Papp10-6cm/s), suggesting potential for oral administration. Metabolic studies indicated that oxadiazole 2i is an inhibitor of cytochrome P450 enzymes CYP1A2 and CYP2C19, necessitating further evaluation of potential drug interactions. Additionally, it did not exhibit hepatotoxicity or cardiotoxicity; however, it demonstrated mutagenic potential in the salmonella reverse mutation test (AMES), which is a genetic method that detects mutagenic chemical agents, thus justifying more complex confirmatory studies. In vitro assays showed that oxadiazole 2i has DPPH (2,2-diphenyl-1-picrylhydrazyl) radical reducing activity, indicating potential antioxidant properties with an IC50 of 12.10µg/mL. Concerning its leishmanicidal mechanism of action, molecular docking simulations at the active site of acetylcholinesterase demonstrated that the 2i molecule had superior binding energy values compared to the reference drug physostigmine (-7.39kcal/mol versus -6.66kcal/mol, respectively). However, the pharmacophore map revealed that physostigmine had more molecular interactions than oxadiazole 2i. In acetylcholinesterase inhibition assays, the 2i molecule exhibited significant inhibitory activity with an IC50 of 11.91µg/mL, suggesting a mechanism of action that compromises the parasitic membrane. Moreover, the 2i molecule demonstrated significant leishmanicidal activity against L. infantum with an IC50 of 30.86μM. Cytotoxicity assays on RAW 264.7 macrophages revealed a high CC50 value of 485.5µM and a selectivity index (SI) of 17.86. Based on these findings, oxadiazole 2i emerges as a promising candidate for further study, offering prospects for more affordable, selective, and less toxic leishmanicidal agents.

Phenolic Acid Profile and In Vitro Antioxidant and Anticholinesterase Activities of Romanian Wild-Grown Acer spp. (Sapindaceae)

This study investigated, for the first time, the phenolic acid profile along with the in vitro antioxidant and acetylcholinesterase (AChE) inhibitory activities of leaves and fruits from five Romanian wild-grown Acer spp. (Sapindaceae): A. campestre L., A. monspessulanum L., A. platanoides L., A. pseudoplatanus L., and A. tataricum L. High-performance liquid chromatography coupled with ultraviolet and mass spectrometry (HPLC/UV/MS) was employed to identify and quantify key phenolic acids, including gallic, caffeic, protocatechuic, chlorogenic, and p-coumaric acids. Total phenolic content (TPC) ranged from 61.48 ± 3.76 to 512.8 ± 20.54 µg gallic acid equivalents (GAE)/mL. Antioxidant activities, assessed through 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, demonstrated the strongest radical scavenging capacities for A. tataricum fruits, with half maximal inhibitory concentration (IC50) values of 10.88 ± 3.39 µg/mL and 10.39 ± 2.86 µg/mL, respectively. The ferric-reducing antioxidant power (FRAP) assay revealed the highest reducing power for A. tataricum fruits (1158 ± 48.98 µmol Fe2+/L) and leaves (1119 ± 164.6 µmol Fe2+/L). AChE inhibition was only found in A. tataricum, with an IC50 of 7.91 ± 7.50 mg/mL for leaves and 15.95 ± 8.52 mg/mL for fruits. These results highlight A. tataricum as a promising source of natural antioxidants and neuroprotective agents.

Outcome Predictors of Generalized Myasthenia Gravis: A Prospective Observational Study.

There is paucity of studies on long-term remission of autoimmune generalized myasthenia gravis (MG) from Southeast Asia. We report the outcome predictors of generalized MG and also evaluate the influence of high- versus low-dose prednisolone and prednisolone with or without azathioprine (AZA). Fifty-seven patients with generalized MG were included, who completed 2 years of follow-up. Demographic information, comorbidities, Myasthenia Gravis Foundation of America (MGFA) class at baseline and follow-up, acetylcholine receptor (AChR) and muscle-specific kinase antibodies, decremental response, thymectomy, and treatments were recorded. Maximum doses of prednisolone, AZA, and acetylcholinesterase inhibitors were noted. The predictors of MGFA 0 at 3 and 6 months and minimal manifestation (MM) status at 2 years were evaluated. MGFA 0 was achieved by 27 (47.4%) patients at 3 months, 35 (61.4%) patients at 6 months, and 46 (80.7%) patients at 12 months. At 2 years, 48 (84.2%) patients achieved the MM status and none achieved complete stable or pharmacologic remission. On multivariate analysis, AChR antibody titer (adjusted odds ratio [AOR] 1.08, 95% confidence interval [CI] 1.006-1.167; P = 0.03) and MG activity of daily living (MGADL) at 6 months (AOR 1.28, 95% CI 1.066-1.558; P = 0.01) predicted the MM status. Maximum dose of prednisolone and adjunctive AZA did not predict the MM status. About 84.2% of patients with generalized MG, especially those with a low AChR antibody titer and MGADL < 4 at 6 months, achieved the MM status at 2 years.

Antioxidant, Enzyme-Inhibitory and Antimicrobial Activity of Underutilized Wheat and Maize Crop Residues

Global wheat and maize production, which reached two billion tonnes in 2021, generates significant agricultural waste with largely untapped potential. This study investigates the bioactive properties of ethanol extracts from wheat and maize harvest residues, their ethyl acetate fractions, and their principal compounds. In vitro assays (DPPH, ABTS, FRAP, and TRC) revealed variable antioxidant capacities among the samples, with ferulic acid demonstrating the strongest free-radical scavenging and reducing effects, often surpassing those of standard antioxidant controls. Enzyme inhibition assays identified the flavonoid tricin as the most effective inhibitor of α-glucosidase, acetylcholinesterase, and butyrylcholinesterase, while the flavonolignan mixture of salcolins A and B showed the highest inhibitory activity against α-amylase and tyrosinase. Antimicrobial testing using the broth microdilution method resulted in minimum inhibitory concentrations (MICs) ranging from 31.25 µg/mL to &gt;1000 µg/mL. Gram-positive bacteria showed the highest susceptibility, Candida albicans exhibited variable sensitivity, and Gram-negative bacteria were resistant in the tested concentration range. Bioactivity increased in the order of extracts, fractions, and then individual compounds. These findings suggest that wheat and maize residues possess notable bioactive properties, highlighting their potential as sources of valuable and pharmacologically active compounds.

Pharmacophore-based virtual screening of the chromone derivatives as potential therapeutic for Alzheimer’s disease

Alzheimer’s disease is one of the most complex neurological disorders and millions of people are suffering from this disease all over the world. In the past two decades acetylcholinesterase (AChE) has been the most explored pathological hallmark. The generation of potent AChE inhibitors has grown as a rapid pathological tool for the efficacious treatment of the disease. Hence, AChE enzyme is extensively explored as a drug discovery tool for the development of potent therapeutics. We have used chromone derivatives with known biological activities for developing a Gaussian field-based 3D QSAR pharmacophore model using PHASE module of Schrodinger with statistically significant R2 and Q2 values of 0.92 and 0.9209, respectively. ChEMBL and MCULE databases were screened using the best pharmacophore hypothesis model (AAHHRR_4) with features of two hydrogen bond acceptors (A1, A2), two hydrophobic regions (H1, H2), and two aromatic regions (R1, R2). These were subjected to structure-based virtual screening using extra precision, MM/GBSA and ADME calculations for calculating the binding free energies and pharmacokinetic properties, respectively. Subsequently, two hit molecules i.e. CHEMBL1319989 and MCULE-2246633290 were identified. The leads exhibited higher docking score (−8.859 and −9.984 kcal/mol) and ΔGbinding (−57.63 and −56.45 kcal/mol) as compared to the reference (ΔGbinding= −53.79 kcal/mol). MD simulation study exhibited stable interactions with the binding free energy (ΔGMMPBSA) of −27.29 and −21.26 kcal/mol for CHEMBL1319989 and MCULE-2246633290, respectively. So, the generated pharmacophore model may be considered as a valuable tool for the development of potent AChE inhibitors for the treatment of AD.

A review on oxidative stress in organophosphate-induced neurotoxicity.

Acetylcholinesterase inhibition, the principal mechanism of acute organophosphorus compound toxicity, cannot explain neuropsychiatric symptoms occurring after exposure to low organophosphate concentrations causing no cholinergic symptoms. Organophosphate-triggered oxidative stress has increasingly come into focus, occurring when the action of reactive oxygen species, generated from free radicals, is not compensated by antioxidant free radical scavengers. Being nucleophilic, organophosphates can easily accept an electron, thereby generating free radicals. Organophosphates inhibit the antioxidant paraoxonase, and reactive oxygen species are produced during organophosphate metabolism. Organophosphates disrupt the function of mitochondria, the principal source of free radicals. Organophosphates also induce neuroinflammation, which generates reactive oxygen species, and reactive oxygen species in turn stimulate neuroinflammation. Markers of reactive oxygen species are elevated in vitro and in vivo after exposure to organophosphates and in individuals professionally exposed to organophosphates. This most probably contributes to the pathogenesis of the intermediate syndrome and chronic organophosphate-induced neuropsychiatric disorders occurring in patients after organophosphate exposure. Evidence for beneficial effects of antioxidants in organophosphate poisoning is discussed.

Evaluation of hesperidin as a potential larvicide against Culex pipiens with computational prediction of its mode of action via molecular docking

Hesperidin, a natural flavanone glycoside predominantly found in citrus fruits, has gained attention for its wide-ranging biological activities, including potential insecticidal properties. Culex pipiens, commonly known as the northern house mosquito, is a major vector of several human pathogens, such as the West Nile virus and filariasis, making it a key target in the fight against vector-borne diseases. In this study, we evaluated the larvicidal activity of Hesperidin against Culex pipiens larvae, assessing its potential as an alternative to chemical insecticides. Hesperidin demonstrated potent larvicidal effects, with a lethal concentration 50 (LC50) of 570.3 ± 0.04 µg/mL, outperforming the conventional insecticide Chlorpyrifos 588.3 ± 0.28 µg/mL in efficacy. Molecular docking simulations revealed a strong binding affinity between Hesperidin and crucial neuroreceptors in Culex pipiens, particularly acetylcholinesterase (AChE), a key enzyme involved in nerve signal transmission. The interaction between Hesperidin’s hydroxyl groups and the AChE enzyme’s active site suggests that AChE inhibition is the primary mechanism driving Hesperidin’s insecticidal action. These findings position Hesperidin as a promising, environmentally friendly alternative to synthetic insecticides. However, further research is needed to assess its toxicity to non-target organisms and optimize its formulation for broader application in mosquito control.

Dual inhibition of AChE and MAO-B in Alzheimer's disease: machine learning approaches and model interpretations.

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases. Given the multifactorial pathophysiology of AD, monotargeted agents can only alleviate symptoms but not cure AD. Acetylcholinesterase (AChE) and Monoamine oxidase B (MAO-B) are two key targets in the treatment of AD, molecules that inhibiting both targets are considered promising avenue to develop more effective AD therapies. In the present work, a dual inhibition dataset containing 449 molecules was established, based on which five machine learning algorithms (KNN, SVM, RF, GBDT, and LGBM) four fingerprints (MACCS, ECFP4, RDKitFP, PubChemFP) and DRAGON descriptors were combined to develop 25 classification models in which GBDT paired with ECFP4 and RF paired with PubchemFP achieved the same best performance across multiple metrics (Accuracy = 0.92, F1 Score = 0.94, MCC = 0.81). Moreover, based on the curated bioactivity datasets of AChE and MAO-B, regression models were developed to predict pIC50 values. For the AChE inhibition task, GBDT demonstrated the best performance (RMSE = 0.683, MAE = 0.500, R2 = 0.721). The SVM algorithm emerged as the most effective for MAO-B inhibition (RMSE = 0.668, MAE = 0.507, R2 = 0.675). The SHAP algorithm was used to interpret the optimal models, identifying and analyzing the key substructures and properties for both dual-target and single-target inhibitors. Moreover, molecules docking process provided potential mechanism and Structure-Activity Relationships (SAR) of dual-target inhibition further.

Salvicsite A-C: Three Seco-Norabietane Diterpenoids Including an Unusual Tetracyclic Skeleton from Salvia castanea Diels f. tomentosa Stib.

Three seco-norabietane diterpenoids, salvicsites A-C (1-3), along with two known compounds, were isolated from the roots and rhizomes of Salvia castanea Diels f. tomentosa Stib. Salvicsite A (1) represents an unprecedented structural combination, featuring an eight-membered α-methyl-α,β-unsaturated lactone ring and a five-membered α,β-unsaturated lactone ring, based on a 6/6/5/8 ring system. Their structures were elucidated through comprehensive spectroscopic analyses, X-ray crystallography, and quantum chemical calculations. Putative biosynthetic pathways of 1-3 were proposed, with compound 5 being the plausible biogenetic precursor. The AChE inhibition assay demonstrated that salvicsite A (1) exhibited a notable inhibitory effect against AChE, with an IC50 value of 9.56 ± 1.05 μM. Enzymatic kinetic studies indicated that salvicsite A (1) acted as a mixed-type inhibitor, and its binding mode was explored through molecular docking. The results of the cytotoxic activity demonstrated that only compound 5 exhibited inhibitory activity.

Environmental impact on phonological stages in Lavandula officinalis: chemical profiling of essential oil and extract, antioxidant activity, and acetylcholinesterase inhibition potential

Environmental impact on phonological stages in Lavandula officinalis: chemical profiling of essential oil and extract, antioxidant activity, and acetylcholinesterase inhibition potential

Cortical Acetylcholine Response to Deep Brain Stimulation of the Basal Forebrain in Mice.

Deep brain stimulation (DBS) using electrical stimulation of neuronal tissue in the basal forebrain to enhance release of the neurotransmitter acetylcholine is under consideration to improve executive function in patients with dementia. While some small studies indicate a positive response in the clinical setting, the relationship between DBS and acetylcholine pharmacokinetics is incompletely understood. We examined the cortical acetylcholine response to different stimulation parameters of the basal forebrain. 2-photon in vivo imaging was combined with deep brain stimulation in C57BL/6J mice. Stimulating electrodes were implanted in the subpallidal basal forebrain, and the ipsilateral somatosensory cortex was imaged. Acetylcholine activity was determined using the GRABACh-3.0 acetylcholine receptor sensor, and blood vessels were visualized with Texas red. Experiments manipulating stimulation frequency demonstrated that integrated acetylcholine induced fluorescence was insensitive to frequency with the same number of pulses, and that maximum peak levels were achieved with frequencies from 60 to 130 Hz. Altering pulse train length indicated that longer stimulation resulted in higher peaks and more activation with sublinear summation. The acetylcholinesterase inhibitor, donepezil, increased the peak response to 10s of stimulation at 60Hz, and the integrated response increased 57% with the 2 mg/kg dose, and 126% with the 4 mg/kg dose. Acetylcholine levels returned to baseline with a time constant of 14 to 18 seconds. Donepezil increases total acetylcholine receptor activation associated with DBS but did not change temporal kinetics. The long time constants observed in the cerebral cortex add to the evidence supporting volume and synaptic neurotransmission.

Thiamine and Thiamine Pyrophosphate as Non-Competitive Inhibitors of Acetylcholinesterase-Experimental and Theoretical Investigations.

Vitamin B1 (thiamine) plays an important role in human metabolism. It is essential for the proper growth and development of the body and has a positive effect on the functioning of the digestive, cardiovascular, and nervous systems. Additionally, it stimulates the brain and improves the psycho-emotional state. In vivo, vitamin B1 occurs in free form as thiamine or as its ester with phosphate residue(s), i.e., as mono-, di-, or triphosphate. It has been proven that supportive therapy with vitamin B1 can not only provide neuroprotection but also has a positive effect on advanced neurodegenerative diseases, such as Parkinson's disease, Alzheimer's disease, Wernicke-Korsakoff syndrome, or Huntington's disease. This paper presents studies on the effect of free thiamine (T) and thiamine pyrophosphate (TPP) on the activity of acetylcholinesterase (AChE), which is an enzyme considered to play an important role in the therapies for neurodegenerative diseases, especially Alzheimer's disease. The mechanisms of action of these compounds as potential inhibitors of AChE were evaluated using both experimental (enzymatic activity) as well as computational (molecular docking, molecular dynamics simulations, and MM-GBSA calculations) methods. The results of the current study indicate a non-competitive type of enzyme inhibition, in contrast to the previously published works suggesting a competitive one.

Rapid screening of acetylcholinesterase inhibitors in Qi-Fu-Yin using magnetic metal-organic frameworks immobilized with acetylcholinesterase.

Current immobilization approaches for ligand fishing often experience challenges such as limited protein loading capacity and difficulties in the recycling process. To overcome these challenges, we synthesized a magnetic metal-organic frameworks (MMOFs) composite, which can be rapidly separated and has a large specific surface area, and employed it to immobilize acetylcholinesterase (AChE). The synthesized MMOFs@AChE composite exhibited a high immobilization yield (129.7mg/g) and excellent relative activity recovery (88.1%). Furthermore, immobilized AChE can improve its resistance to alkaline environments and high temperatures. After being stored at 4°C for a month, the immobilized enzyme maintained 91.4% of its original activity, significantly higher than the free enzyme (77.6%). Furthermore, it preserved more than 80% of its initial activity after five cycles and 68.7% after eight cycles. The composite MMOFs@AChE was then incubated with Qi-Fu-Yin extract to fish for ligands binding to AChE. Notably, Qi-Fu-Yin can alleviate Alzheimer's disease (AD) symptoms by modulating the AChE pathway, while active compounds remain unclear. Sixteen potential AChE inhibitors were identified through UHPLC-Q-Exactive-Orbitrap-MS/MS. The results of ligand fishing were validated through molecular docking studies, molecular dynamics simulation, surface plasmon resonance and AChE inhibitory activity assays. The screened compounds may exert inhibitory effects on AChE by altering the spatial configuration of the catalytic site or by influencing the binding of the substrate to the catalytic site, catalytic anionic site and peripheral anionic site regions. The MMOFs@AChE-based ligand fishing platform offers an efficient, effective, and convenient approach for enzymatic inhibitors discovery from natural products.

Recovery of Bioactive Constituents from Olive Leaf Pruning Waste of Five Different Cultivars: A Comparison of Green Extraction Techniques to Maximize Health Benefits.

Sustainable agro-waste revaluation is critical to enhance the profitability and environmental footprint of the olive oil industry. Herein, the valorization of olive leaf pruning waste from five cultivars ('Caiazzana', 'Carolea', 'Itrana', 'Leccino', and 'Frantoio') employed green extraction methods to recover compounds with potential health benefits. Sequential ultrasound-assisted maceration (UAM) in n-hexane and ethanol was compared with a compressed fluid extraction strategy consisting of supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) for their efficiency in recovering distinct classes of bioactives. Chemical profiling by UHPLC-HR-MS/MS (ultra-high-performance liquid chromatography high-resolution tandem mass spectrometry) and GC-MS (gas chromatography mass spectrometry) showed that UAM-EtOH effectively extracted polyphenols (especially luteolin derivatives) and triterpenes (notably maslinic acid), while PLE yielded the highest amount of secoiridoids (e.g., secologanoside). PLE extracts showed better antiradical activities, putatively due to a higher content of flavonoids, secoiridoids, and HCA derivatives than UAM-EtOH ones, as these latter also contained 20-40% (cultivar-dependent) of triterpenes. SFE extracts with a higher concentration of fatty acids and triterpenes showed moderate antioxidant activities but very high AChE inhibition. This study highlights the importance of selecting appropriate extraction methodologies based on the target bioactive compounds and underscores the potential of olive leaf extracts for sustainable bio-products.

New Horizons in Menopause, Menopausal Hormone Therapy, and Alzheimer's Disease: Current Insights and Future Directions.

Accumulating evidence suggests that the effects of menopausal hormone therapy (MHT) on risk of Alzheimer's disease (AD) and all-cause dementia are influenced by timing of initiation relative to age and time-since-menopause and the type of formulation. Randomized clinical trials (RCTs) of MHT conducted in older postmenopausal women indicate an increased risk of dementia. While RCTs conducted in midlife are lacking, observational research has provided evidence for associations between midlife estrogen-only therapy (ET) use and a reduced risk of AD dementia, whereas estrogen-progestogen therapy (EPT) is associated with more variable outcomes. However, existing studies are heterogenous, and conventional endpoints might not adequately assess MHT's potential for AD prevention. Herein, several approaches are being discussed, and the case is being made for utilizing AD biomarkers for assessment of early, AD-specific outcomes in relation to MHT use. From a clinical standpoint, findings that MHT may lower dementia risk warrant consideration as existing therapies like acetylcholinesterase inhibitors and memantine lack preventative efficacy, and vaccines for primary or secondary prevention are not yet available. MHT-associated risks, including breast cancer, stroke and venous thromboembolism, are generally considered rare (<10 events/10,000 women). Overall, the literature supports renewed interest in evaluating MHT as a sex-specific, time-sensitive approach for AD risk reduction, which is key to applying cumulated data in clinical decision making concerning AD prevention.

Neuroprotective Potential of Origanum majorana L. Essential Oil Against Scopolamine-Induced Memory Deficits and Oxidative Stress in a Zebrafish Model.

Origanum majorana L., also known as sweet marjoram, is a plant with multiple uses, both in the culinary field and traditional medicine, because of its major antioxidant, anti-inflammatory, antimicrobial, and digestive properties. In this research, we focused on the effects of O. majorana essential oil (OmEO, at concentrations of 25, 150, and 300 μL/L), evaluating chemical structure as well as its impact on cognitive performance and oxidative stress, in both naive zebrafish (Danio rerio), as well as in a scopolamine-induced amnesic model (SCOP, 100 μM). The fish behavior was analyzed in a novel tank-diving test (NTT), a Y-maze test, and a novel object recognition (NOR) test. We also investigated acetylcholinesterase (AChE) activity and the brain's oxidative stress status. In parallel, we performed in silico predictions (research conducted using computational models) of the pharmacokinetic properties of the main compounds identified in OmEO, using platforms such as SwissADME, pKCSM, ADMETlab 2.0, and ProTox-II. The results revealed that the major compounds were trans-sabinene hydrate (36.11%), terpinen-4-ol (17.97%), linalyl acetate (9.18%), caryophyllene oxide (8.25%), and α-terpineol (6.17%). OmEO can enhance memory through AChE inhibition, reduce SCOP-induced anxiety by increasing the time spent in the top zone in the NTT, and significantly reduce oxidative stress markers. These findings underscore the potential of using O. majorana to improve memory impairment and reduce oxidative stress associated with cognitive disorders, including Alzheimer's disease (AD).

Unraveling Chemical Profile, Antioxidant, Antialzheimer and Antimicrobial Potentials of Three Propolis from Northeastern Regions of Algeria: In Vitro and in Silico Evaluation.

This study investigates the pharmaceutical potential both in vitro and in silico of ethanolic propolis extract from three Algerian regions namely TAH (Tahir-Jijel), ATH (Oued Athmania-Mila) and OZ (Oued Zhor-skikda). Twenty-three compounds were identified via HPLC‒DAD, with key constituents including caffeic acid, cynarin, chrysin, naringin, and hesperetin. Moreover, Antioxidant and anti-Alzheimer activities were assessed by multiple assays. Antimicrobial activity was tested against four pathogens and one yeast. The TAH extract showed the highest antioxidant activity, and ATH (Oued Athmania-Mila) exhibited the strongest anticholinesterase activity. Extracts demonstrated potent inhibition against Staphylococcus aureus and Micrococcus luteus ATCC 4698. Docking studies revealed that cynarin was the most potent acetylcholinesterase (AChE) inhibitor, and quercetin was the most potent butyrylcholinesterase (BChE) inhibitor; These compounds were found to bind to both the catalytic site and the peripheral site, showing greater inhibitory potency than galantamine.

Revisiting the Metabolism of Donepezil in Rats Using Non-Targeted Metabolomics and Molecular Networking.

Background/Objectives: Although donepezil, a reversible acetylcholinesterase inhibitor, has been in use since 1996, its metabolic characteristics remain poorly characterized. Therefore, this study aims to investigate the in vivo metabolism of donepezil using liquid chromatography-high-resolution mass spectrometry (LC-HRMS) based on a molecular networking (MN) approach integrated with a non-targeted metabolomics approach. Methods: After the oral administration of donepezil (30 mg/kg) in rats, urine, feces, and liver samples were collected for LC-HRMS analysis. Chromatographic and spectrometric data were processed through MN and multivariate data analysis to identify the in vivo metabolites of donepezil. Results: A total of 50 metabolites were characterized, including 23 newly identified metabolites. Donepezil was biotransformed by O-demethylation, N-debenzylation, and hydroxylation, and these metabolites are further conjugated with glucuronic acid and sulfurous acid. N-Desbenzyldonepezil (M4), didesmethyldonepezil (M5), and N-desbenzyldonepezil (M4) were identified as the most abundant metabolites in urine, feces, and liver samples, respectively. Conclusions: The metabolic characteristics of donepezil in rats were comparable to those in humans, indicating that a rat is a reliable model for studying donepezil metabolism. This study indicates that a MN approach combined with a metabolomics approach is a reliable tool to identify unknown metabolites of drugs and drug candidates.