Ameliorative potential of ethanol extract of Calyptrochilum emarginatum leaves on scopolamine-induced amnesia in male swiss mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Calyptrochilum emarginatum (Afzel. Ex Sw.) Schltr. (Orchidaceae) is a traditional medicinal plant known for its antimicrobial properties and efficacy in managing convulsive fever and menstrual disorders and addressing conditions such as malaria, tuberculosis, and cough. AIM OF THE STUDY: The study aims to examine the memory-enhancing and neuroprotective properties of ethanol extract of Calyptrochilum emarginatum leaves (EECEL) in scopolamine-induced amnesia mice model. MATERIALS AND METHODS: Forty-two male mice were divided into six groups (n = 7). Group 1 served as control, administered distilled water (10 mL/kg, p. o), group 2 received scopolamine only (3 mg/kg, i. p.), groups 3 to 6 received pretreatments of EECEL (50, 100, and 200 mg/kg, p. o.) and donepezil (1 mg/kg, p. o.) 30 min before scopolamine (3 mg/kg), for seven days. Following treatments, behavioral (learning and memory) assessments were carried out, while biochemical (acetylcholinesterase activity, oxidative stress markers, inflammatory cytokines markers) and histological evaluations were done after euthanasia. RESULTS: Scopolamine significantly impaired spatial, long term and recognition memory. Nevertheless, administration of EECEL (50, 100, and 200 mg/kg orally) enhanced memory function in mice, as observed in the Y maze [F (5, 30) = 20.23, p < 0.0001], Morris water maze [F (10, 90) = 3.105, p = 0.0019; [F (5, 30) = 21.13, p < 0.0001]], and novel object recognition tasks [F (5, 30) = 37.22, p < 0.0001)]. Scopolamine-treated mice exhibited significant dysfunction in the cholinergic system, as evidenced by elevated AChE activity [0.099 ± 0.005 vs. 0.063 ± 0.004 mol/min/g] with an elevation in oxidative stress. On the other hand, administration of EECEL counteracted these consequences by reducing AChE activity, mitigating oxidative damage, reducing pro-inflammatory cytokines, and preventing degeneration of neurons. CONCLUSION: The results demonstrated that EECEL effectively mitigates scopolamine-induced memory impairment via an oxido-inflammatory mechanism and modulation of the central cholinergic system.

Synthesis and evaluation of lipoic acid - donepezil hybrids for Alzheimer's disease using a straightforward strategy.

Alzheimer's disease is associated with a progressive loss of neurons and synaptic connections in the cholinergic system. Oxidative stress contributes to neuronal damages and to the development of amyloid plaques and neurofibrillary tangles. Therefore, antioxidants have been widely studied to mitigate the progression of Alzheimer's disease, and among these, lipoic acid has demonstrated a neuroprotective effect. Here, we present the synthesis, the molecular modelling, and the evaluation of lipoic acid-donepezil hybrids based on O-desmethyldonepezil. As compounds 5 and 6 display a high inhibition of acetylcholinesterase (IC50 = 7.6 nM and 9.1 nM, respectively), selective against butyrylcholinesterase, and a notable neuroprotective effect, slightly better than that of lipoic acid, the present study suggests that O-desmethyldonepezil could serve as a platform for the straightforward design of donepezil hybrids.

Effect of long-term pharmacological treatments on Alzheimer disease: A systematic review and network meta-analysis.

BACKGROUND: To analyze and compare the pharmacological treatments for Alzheimer disease (AD), we will conduct a systematic review and network meta-analysis focusing on their efficacy and safety over a duration exceeding 1 year. METHODS: We searched the databases of PubMed, Scopus, EMBASE, Web of Science, the Cochrane Central Register of Controlled Trials, and CNKI until July 30, 2023, for randomized controlled trials (RCTs) evaluating pharmacological treatments for AD. RESULTS: Seventeen RCTs, comprising 7214 participants, investigated the efficacy of the following drugs: Donepezil, Rivastigmine, Galantamine, Memantine, Ginkgo biloba extract (EGb), Atorvastatin-calcium and Vitamin B in the treatment of AD. The network meta-analysis resulted indicated that placebo demonstrated greater effectiveness compared to Atorvastatin-calcium 80 mg (mean different [MD] = -6.93, confidence interval [CI] -11.57, -2.29) and Rivastigmine 12 mg (MD = -3.33, CI -6.56, -0.09). EGb120 mg exhibited a greater improvement in cognition compared to Atorvastatin-calcium 80 mg (MD = 7.77, CI 2.07, 13.46) and Rivastigmine 12 mg + EGb120 mg (MD = 9.92, CI 1.32, 17.22). EGb 120 mg emerged as the most efficient intervention for cognition, while placebo demonstrated the least harm over a period exceeding 1 year. CONCLUSIONS: In this network meta-analysis of studies of patients with AD and a follow-up period of at least 1 year, EGb 120 mg demonstrated cognitive benefits, while placebo posed the least harm for AD. More RCTs are required to address the uncertainty surrounding the efficacy of medication.

Pharmacological intervention of behavioural traits and brain histopathology of prenatal valproic acid-induced mouse model of autism.

Autism spectrum disorder (ASD) is one of the leading causes of distorted social communication, impaired speech, hyperactivity, anxiety, and stereotyped repetitive behaviour. The aetiology of ASD is complex; therefore, multiple drugs have been suggested to manage the symptoms. Studies with histamine H3 receptor (H3R) blockers and acetylcholinesterase (AchE) blockers are considered potential therapeutic agents for the management of various cognitive impairments. Therefore, the aim of this study was to evaluate the neuro-behavioural effects of Betahistine, an H3R antagonist, and Donepezil, an acetylcholinesterase inhibitor on Swiss albino mouse model of autism. The mice were intraperitoneally injected with valproic acid (VPA) on the embryonic 12.5th day to induce autism-like symptoms in their offspring. This induced autism-like symptoms persists throughout the life. After administration of different experimental doses, various locomotor tests: Open Field, Hole-Board, Hole Cross and behavioural tests by Y-Maze Spontaneous Alternation and histopathology of brain were performed and compared with the control and negative control (NC1) groups of mice. The behavioural Y-Maze test exhibits significant improvement (p <0.01) on the short term memory of the test subjects upon administration of lower dose of Betahistine along with MAO-B inhibitor Rasagiline once compared with the NC1 group (VPA-exposed mice). Furthermore, the tests showed significant reduction in locomotion in line crossing (p <0.05), rearing (p <0.001) of the Open Field Test, and the Hole Cross Test (p <0.01) with administration of higher dose of Betahistine. Both of these effects were observed upon administration of acetylcholinesterase inhibitor, Donepezil. Brain-histopathology showed lower neuronal loss and degeneration in the treated groups of mice in comparison with the NC1 VPA-exposed mice. Administration of Betahistine and Rasagiline ameliorates symptoms like memory deficit and hyperactivity, proving their therapeutic effects. The effects found are dose dependent. The findings suggest that H3R might be a viable target for the treatment of ASD.

Liposomal Formulations of Anti-Alzheimer Drugs and siRNA for Nose-to-Brain Delivery: Design, Safety and Efficacy In Vitro.

ß-site amyloid precursor protein cleaving enzyme (BACE1) represents a key target for Alzheimer's disease (AD) therapy because it is essential for producing the toxic amyloid ß (Aß) peptide that plays a crucial role in the disease's development. BACE1 inhibitors are a promising approach to reducing Aß levels in the brain and preventing AD progression. However, systemic delivery of such inhibitors to the brain demonstrates limited efficacy because of the presence of the blood-brain barrier (BBB). Nose-to-brain (NtB) delivery has the potential to overcome this obstacle. Liposomal drug delivery systems offer several advantages over traditional methods for delivering drugs and nucleic acids from the nose to the brain. The current study aims to prepare, characterize, and evaluate in vitro liposomal forms of donepezil, memantine, BACE-1 siRNA, and their combination for possible treatment of AD via NtB delivery. All the liposomal formulations were prepared using the rotary evaporation method. Their cellular internalization, cytotoxicity, and the suppression of beta-amyloid plaque and other pro-inflammatory cytokine expressions were studied. The Calu-3 Transwell model was used as an in vitro system for mimicking the anatomical and physiological conditions of the nasal epithelium and studying the suitability of the proposed formulations for possible NtB delivery. The investigation results show that liposomes provided the effective intracellular delivery of therapeutics, the potential to overcome tight junctions in BBB, reduced beta-amyloid plaque accumulation and pro-inflammatory cytokine expression, supporting the therapeutic potential of our approach.

Optimized method development and validation for determining donepezil in rat plasma: A liquid-liquid extraction, LC-MS/MS, and design of experiments approach.

Donepezil (DPZ), a piperidine-based reversible cholinesterase inhibitor, finds extensive use in treating Alzheimer's disease (AD). Originally designed as an oral formulation, DPZ encounters drawbacks such as a brief duration of action and reduced treatment effectiveness in elderly patients with memory impairment or difficulty swallowing medications. To address these issues and improve patient compliance, researchers are actively exploring alternative DPZ formulations. Consequently, reliable methods are necessary to quantitate DPZ in biological samples for in vivo assessment. Therefore, we propose an efficient, sensitive, wide-dynamic, and cost-effective method for quantitating DPZ in rat plasma. Our method employs liquid-liquid extraction (LLE) followed by liquid chromatography and tandem mass spectrometry, enabling in vivo evaluation of novel DPZ formulations. Notably, our method requires only 20 µL of rat plasma and employs icopezil as the internal standard-a cost-effective compound with chemical similarity to DPZ. We meticulously optimized LLE conditions, taking into account factor interactions through design of experiments (DOE). Our rapid and straightforward extraction and purification involved using 500 µL of pure methyl tert-butyl ether to extract DPZ from the sample within five minutes. The dynamic range of the method extends from 0.5 ng/mL to 1,000 ng/mL, demonstrating excellent sensitivity and suitability for pharmacokinetic studies across diverse DPZ formulations. Following the FDA guidelines, we rigorously validated the developed method, evaluating selectivity, linearity (with a coefficient of determination ≥0.9999), accuracy (ranging from 96.0% to 109.6%), precision (≤13.9%), matrix effect (92.2% to 103.8%), recovery (98.5% to 106.8%), the lower limit of quantitation (0.5 ng/mL), and stability. Finally, we effectively employed the validated method for the long-term pharmacokinetic assessment of a DPZ formulation. We expect that this approach will make a substantial contribution to the advancement of new DPZ formulations, ultimately benefiting individuals afflicted by AD.

Donepezil Nanoemulsion Induces a Torpor-like State with Reduced Toxicity in Nonhibernating Xenopus laevis Tadpoles.

Achieving a reversible decrease of metabolism and other physiological processes in the whole organism, as occurs in animals that experience torpor or hibernation, could contribute to increased survival after serious injury. Using a Bayesian network tool with transcriptomic data and chemical structure similarity assessments, we predicted that the Alzheimer's disease drug donepezil (DNP) could be a promising candidate for a small molecule drug that might induce a torpor-like state. This was confirmed in a screening study with Xenopus laevis tadpoles, a nonhibernator whole animal model. To improve the therapeutic performance of the drug and minimize its toxicity, we encapsulated DNP in a nanoemulsion formulated with low-toxicity materials. This formulation is composed of emulsified droplets <200 nm in diameter that contain 1.250 mM DNP, representing ≥95% encapsulation efficiency. The DNP nanoemulsion induced comparable torpor-like effects to those produced by the free drug in tadpoles, as indicated by reduced swimming motion, cardiac beating frequency, and oxygen consumption, but with an improved biodistribution. Use of the nanoemulsion resulted in a more controlled increase of DNP concentration in the whole organism compared to free DNP, and to a higher concentration in the brain, which reduced DNP toxicity and enabled induction of a longer torpor-like state that was fully reversible. These studies also demonstrate the potential use of Xenopus tadpoles as a high-throughput in vivo screen to assess the efficacy, biodistribution, and toxicity of drug-loaded nanocarriers.

The combination of donepezil and cognitive training for improving treatment outcomes for alcohol use disorder: Design of a randomized controlled trial.

BACKGROUND: The development of alcohol use disorder (AUD) is a major concern in public health, and cognitive impairments caused by alcohol are involved in this process. Emerging neurobiological evidence suggests that donepezil, an anticholinesterase agent, may improve AUD treatment outcomes by enhancing neurocognitive functioning. Previous research has also suggested that cognitive remediation therapy (CRT) could potentially improve cognitive function and AUD treatment outcomes. We present the rationale and design of a trial to evaluate the combination of donepezil and cognitive remediation therapy (donepezil + CRT) as an intervention for AUD. METHODS: We propose a 13-week, randomized, double-blind, placebo-controlled, between-subjects trial comparing 4 groups (donepezil + CRT vs. donepezil alone vs. CRT alone vs. placebos) as an intervention for AUD. The main goal of the study is to evaluate if donepezil + CRT is superior to placebo in reducing heavy drinking days and improving neurocognitive functioning. A total of 160 patients (4 groups, 40 per each group) with AUD between the ages of 18-80 years will be recruited at Yale University and the VA Connecticut Healthcare System. Primary outcome measures include 1) heavy drinking by Timeline Follow Back (TLFB) over 13 weeks and 2) global neurocognitive functioning by a global index of neurocognitive function score at 7 and 13 weeks. DISCUSSION: This protocol paper describes the rationale and proposed methods for the randomized controlled trial for improving AUD treatment outcomes. This project has significant clinical potential to help patients suffering from AUD by improving their cognition and reducing alcohol consumption. TRIAL REGISTRATION: NCT05042102.

[A case of Parkinson's disease with marked head drop after administration of donepezil hydrochloride].

A 76-year-old woman with a 2-year history of Parkinson's disease presented with dropped head, which had developed rapidly after she had been prescribed donepezil hydrochloride (DNP) at 3 |mg/day. After one month of medication, the extent of the head drop reached 90°. Examination revealed hypertrophy of the left sternocleidomastoid muscle, but no weakness of the extensor muscles in the cervical region. Surface electromyography demonstrated co-|contraction of the sternocleidomastoid and splenius capitus muscles during head flexion and extension. DNP was withdrawn, resulting in immediate amelioration of the head drop, and complete resolution was achieved after two months. Although head drop is often seen in patients with Parkinson's disease, few previous reports have documented DNP as a causative factor. If patients with Parkinson's disease develop head drop, it is important to investigate any history of DNP medication.

Enhancing Outcomes in Alzheimer's Disease: Exploring the Effects of a Diversified Rehabilitation Program Combined with Donepezil on Apathy, Cognitive Function, and Family Caregiver Burden.

BACKGROUND AND OBJECTIVE: Alzheimer's disease is a progressive neurodegenerative disorder characterized by cognitive decline, behavioral changes, and functional impairments. Apathy, a common symptom in Alzheimer's disease, refers to a lack of motivation, interest, and emotional responsiveness. It can significantly impact patients' quality of life and increase caregiver burden. This study aimed to determine the effects of a diversified rehabilitation program combined with donepezil on apathy, cognitive function, and family caregiver burden of Alzheimer's disease patients. METHODS: A total of 105 Alzheimer's disease patients treated at our hospital between January 2020 and January 2023 were selected and analyzed retrospectively. They were assigned to the control group (n = 50) or the observation group (n = 55). The two groups did not differ in terms of general data such as age and sex. All patients were treated with donepezil orally. The control group was given routine nursing, whereas the observation group was given a diversified rehabilitation program intervention, including cognitive training and emotional support. The Hasegawa's dementia scale, mini-mental state examination, and Montreal cognitive assessment scale were adopted to evaluate the cognitive function of the two groups before and after treatment. A caregiver burden scale, the Zarit Burden Interview (ZBI) and the Apathy Evaluation Scale Informant version (AES-I) were used to evaluate the caregiver burden and apathy of the two groups. RESULTS: A significantly higher overall response rate to treatment was found in the observation group (94.55%) than in the control group (80.00%) (p = 0.024). After treatment, scores on the Hasegawa's dementia scale, mini-mental state examination, and Montreal cognitive assessment scale of the two groups increased to varying degrees, with greater increases in the observation group than in the control group (p < 0.05). The ZBI and AES-I scores of the two groups decreased to different degrees after treatment, with greater decreases in the observation group than in the control group (p < 0.05). CONCLUSION: A diversified rehabilitation program combined with donepezil can substantially alleviate the apathy of Alzheimer's disease patients, improve their cognitive function, and reduce the burden on their families.

The Impact of Combined Application of Donepezil and Nimodipine on Patients with Comorbid Cerebral Small Vessel Disease and Cognitive Dysfunction: Efficacy and Influence on Nutritional Status.

BACKGROUND AND OBJECTIVE: Cerebral small vessel disease (CSVD) often coexists with cognitive dysfunction in patients, leading to significant challenges in treatment and management. This study aimed to examine the efficacy of combined application of donepezil and nimodipine on patients with comorbid CSVD and cognitive dysfunction and the effects on patients' albumin and prealbumin levels. METHODS: The records of 112 patients with comorbid CSVD and cognitive dysfunction treated at the People's Hospital of Suzhou New District from January 2019 to December 2022 were analysed retrospectively. A total of 50 patients receiving donepezil were allocated to the control group, and 62 patients receiving both nimodipine and donepezil to the study group. Outcomes compared between the two groups included serum homocysteine (Hcy), high sensitivity C-reactive protein (hs-CRP), albumin, and prealbumin before and after therapy, efficacy, and adverse reactions. Additionally, logistic regression was performed to analyze the risk factors impacting patient prognosis. RESULTS: Prior to therapy, the two groups did not differ significantly in Hcy and hs-CRP levels (p > 0.05), whereas after therapy, the levels in both groups dropped significantly (p < 0.01), with more obvious lower levels in the study group (p < 0.05). After treatment, the study group presented significantly higher albumin and prealbumin levels than the control group (p < 0.001). An obvious higher overall response rate was observed in the study group compared to the control group (p = 0.012). No significant inter-group discrepancy was found regarding the total incidence of adverse reactions (p = 0.752). Univariate analysis identified age, course of disease, heart rate (HR), Montreal Cognitive Assessment (MoCA) score, diastolic blood pressure (DBP), systolic blood pressure (SBP), drinking history, as well as medication regimen as risk factors impacting patient prognosis. Multivariate logistic regression analysis identified SBP, DBP, and medication regimen as the independent risk factors. CONCLUSION: Combined application of donepezil and nimodipine can effectively treat patients with comorbid CSVD and cognitive dysfunction. It can significantly lower the Hcy and hs-CRP levels and improve the nutritional status without increasing the frequency of adverse reactions. In addition, for CSVD patients with cognitive dysfunction, age, course of disease, MoCA score, HR, SBP, DBP, drinking history, and medication regimen are risk factors impacting patient prognosis, while SBP, DBP, and medication regimen are independent risk factors.

Neuroprotective Effect of Famotidine in Mouse Models of Alzheimer's Disease.

BACKGROUND: Famotidine is a competitive histamine H-receptor antagonist that reduces the formation of stomach acid and is used to treat gastrointestinal disorders associated with acid reflux, gastroesophageal reflux disease, duodenal ulcer, gastric ulcer, and pathological hypersecretory disorders. This study is designed to investigate the possible neuroprotective effects of the ranolazine scopolamine-induced Alzheimer's disease-like feature in a mouse model. METHODS: Mice were divided equally into five groups (ten mice per group), including control group and induction group. The mice in the induction group were administered scopolamine 1 mg/kg i.p., once daily for 7 days, to induce features similar to Alzheimer's disease. The mice in the remaining three treatment groups were given tested medications prophylactically for 14 days. After that the induction was carried out with scopolamine 1 mg/kg i.p., once daily, while the tested medication dosages were continued for an additional 7 days. These treatment groups included: the donepezil group (5 mg/kg/day), the famotidine group (40 mg/kg/day) and the combined group with donepezil (5 mg/kg/day) and famotidine (40 mg/kg/day); all were administrated i.p., once daily. Behavioral parameters were assessed, among others with the Y-maze test and novel object recognition test, and the inflammatory cytokines and oxidative stress parameters were assessed as well. RESULTS: Famotidine exhibits significant improvements in behavior and memory, level of oxidative stress parame-ter, and inflammatory cytokines. CONCLUSIONS: Famotidine and its combination at prescribed doses in the current study improved learning and memory impairments in mice model of Alzheimer's disease probably via their antioxidant and anti-inflammatory properties confirmed by a significant increase in antioxidant mediator and a significant decrease in oxidative stress marker and inflammatory cytokines.

Speech-related parameters are sensitive measures of acetylcholinesterase inhibitor therapy in mild Alzheimer's disease.

Our aim was to find out whether speech-related temporal parameters (SRTPs) are sensitive indicators of the clinical outcome in acetylcholinesterase (AChE) inhibitor therapy with donepezil, compared to the standard cognitive Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) used in clinical trials. In this 24-week-long, naturalistic, self-control, open-labeled, prospective pilot study with 10 mg donepezil on 20 mild AD patients, cognitive functions were evaluated using 15 different SRTPs analyzed by automatic speech recognition in the Speech-Gap Test® compared to ADAS-Cog test results. Among the SRTPs, the filled pause duration ratio significantly improved after 12 weeks of donepezil treatment. During the 24-week follow-up, additional SRTPs such as the filled pause count ratio and the filled pause frequency showed significant benefits. ADAS-Cog total scores showed a slight but not significant improvement compared to baseline after 12 and 24 weeks of donepezil treatment. Among the ADAS-Cog subtests, only orientation improved significantly after 24 weeks of donepezil treatment. Our results indicate that subtle changes in SRTPs measured by the Speech-Gap Test® could be considered as sensitive indicators of the efficacy of the pharmacotherapy in mild AD. According to our data, other cognitive domains did not show improvement in response to donepezil therapy rating by ADAS-Cog. Based on all of this, it is likely that examining and evaluating speech parameters may play an important role in determining the effects of pharmacological treatment of mild AD. The novelty of our study is that it applies the measurement of linguistic parameters as primary outcomes during a drug trial of mild AD in scientific research for the first time.

Fabrication of Hybrid Coated Microneedles with Donepezil Utilizing Digital Light Processing and Semisolid Extrusion Printing for the Management of Alzheimer's Disease.

Microneedle (MN) patches are gaining increasing attention as a cost-effective technology for delivering drugs directly into the skin. In the present study, two different 3D printing processes were utilized to produce coated MNs, namely, digital light processing (DLP) and semisolid extrusion (SSE). Donepezil (DN), a cholinesterase inhibitor administered for the treatment of Alzheimer's disease, was incorporated into the coating material. Physiochemical characterization of the coated MNs confirmed the successful incorporation of donepezil as well as the stability and suitability of the materials for transdermal delivery. Optical microscopy and SEM studies validated the uniform weight distribution and precise dimensions of the MN arrays, while mechanical testing ensured the MNs' robustness, ensuring efficient skin penetration. In vitro studies were conducted to evaluate the produced transdermal patches, indicating their potential use in clinical treatment. Permeation studies revealed a significant increase in DN permeation compared to plain coating material, affirming the effectiveness of the MNs in enhancing transdermal drug delivery. Confocal laser scanning microscopy (CLSM) elucidated the distribution of the API, within skin layers, demonstrating sustained drug release and transcellular transport pathways. Finally, cell studies were also conducted on NIH3T3 fibroblasts to evaluate the biocompatibility and safety of the printed objects for transdermal applications.

Cytochrome P450-mediated metabolic interactions between donepezil and tadalafil in human liver microsomes.

Donepezil and tadalafil, commonly prescribed among older persons to treat dementia and erectile dysfunction, respectively, are primarily metabolized by cytochrome P450 (CYP) 3A4. However, the drug-drug interactions (DDIs) of these drugs are unknown. Therefore, this study evaluated the CYP-mediated metabolic interaction between donepezil and tadalafil using pooled human liver microsomes (HLMs) to predict their DDI potential. Donepezil metabolism was tadalafil-concentration dependently changed in HLMs incubated with 0.1 µM donepezil and showed the maximum 32.3% increase in the donepezil half-life at 1 µM tadalafil. The formation rates of donepezil metabolites, such as N-desbenzyl donepezil and 3-hydroxy donepezil, decreased by 28.3% and 30.3%, respectively, in HLMs incubated with 1 µM tadalafil and 0.1 µM donepezil. In contrast, neither the half-life of tadalafil nor the production rate of its metabolite, desmethylene tadalafil, was changed by >20% in the presence of donepezil (up to 1 µM). CYP3A4 activity was inhibited by tadalafil with an IC50 value of 22.6 µM but not by donepezil. After pre-incubating HLMs with tadalafil and NADPH, the tadalafil IC50 value against CYP3A4 was approximately 7.04-fold lower, suggesting time-dependent tadalafil inhibition. This study shows that the DDI between donepezil and tadalafil is primarily due to time-dependent inhibition against CYP3A4 by tadalafil.

Synthesis and Biological Evaluation of Colchicine─Aryl/Alkyl Amine Hybrids as Potential Noncytotoxic Cholinesterase Inhibitors: Identification of SBN-284 as a Dual Inhibitor of Cholinesterases and NLRP3 Inflammasome.

Colchicine, one of the oldest anti-inflammatory natural products still used clinically, inhibits NF-κB signaling and NLRP3 inflammasome activation. Despite its cytotoxicity and narrow therapeutic range, colchicine continues to intrigue medicinal chemists exploring its anti-inflammatory potential. This study aimed to investigate the colchicine scaffold for its role in Alzheimer's disease by targeting neuroinflammation and cholinesterases. Molecular docking revealed that colchicine's hydrophobic trimethoxyphenyl framework can potentially bind to the peripheral anionic site of cholinesterases. Hybrid structures combining colchicine with aryl/alkyl amines were designed to bind both peripheral and catalytic sites of cholinesterases. We describe here the design, synthesis, and in vitro cytotoxicity evaluation of these colchicine-aryl/alkyl amine hybrids, along with their in silico interactions with the cholinesterase active site gorge. Nontoxic analogs demonstrating strong cholinesterase binding affinity were further evaluated for their anticholinesterase and antineuroinflammatory activities. The colchicine-donepezil hybrid, SBN-284 (3x), inhibited both acetylcholinesterase and butyrylcholinesterase as well as the NLRP3 inflammasome complex at low micromolar concentrations. It achieved this through noncompetitive inhibition, occupying the active site gorge and interacting with both peripheral and catalytic anionic sites of cholinesterases. Analog 3x was shown to cross the blood-brain barrier and exhibited no toxicity to neuronal cells, primary macrophages, or epithelial fR2 cells. These findings highlight the potential of this lead compound for further preclinical investigation as a promising anti-Alzheimer agent.

Effect of curcumin-donepezil combination on spatial memory, astrocyte activation, and cholinesterase expressions in brain of scopolamine-treated rats.

BACKGROUND: The study investigated the effect of co-administration of curcumin and donepezil on several markers of cognitive function (such as spatial memory, astrocyte activation, cholinesterase expressions) in the brain cortex and hippocampus of scopolamine-treated rats. METHOD AND RESULTS: For seven consecutive days, a pre-treatment of curcumin (50 mg/kg) and/or donepezil (2.5 mg/kg) was administered. On the seventh day, scopolamine (1 mg/kg) was administered to elicit cognitive impairment, 30 min before memory test was conducted. This was followed by evaluating changes in spatial memory, cholinesterase, and adenosine deaminase (ADA) activities, as well as nitric oxide (NO) level were determined. Additionally, RT-qPCR for glial fibrillary acidic protein (GFAP) and cholinesterase gene expressions was performed in the brain cortex and hippocampus. Also, GFAP immunohistochemistry  of the brain tissues for neuronal injury were performed in the brain cortex and hippocampus. In comparison to the control group, rats given scopolamine had impaired memory, higher levels of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and ADA activities, as well as elevated markers of oxidative stress. In addition to enhanced GFAP immunoreactivity, there was also overexpression of the GFAP and BChE genes in the brain tissues. The combination of curcumin and donepezil was, however, observed to better ameliorate these impairments in comparison to the donepezil-administered rat group. CONCLUSION: Hence, this evidence provides more mechanisms to support the hypothesis that the concurrent administration of curcumin and donepezil mitigates markers of cognitive dysfunction in scopolamine-treated rat model.

Simultaneous estimation of rutin and donepezil through RP-HPLC: implication in pharmaceutical and biological samples.

Aim: A HPLC method was developed and validated for the novel combination of rutin (RN) and donepezil (DNP). Materials & methods: RN and DNP were simultaneously eluted through a C18 column (Ø 150 × 4.6 mm) with a 60:40 v/v ratio of 0.1% formic acid aqueous solution to methanol at 0.5 ml/min. Results: The purposed method was found linear, selective, reproducible, accurate and precise with percent RSD less than 2. The limit of quantification for RN and DNP was found 3.66 and 3.25 µg/ml, respectively. Conclusion: Validated as per the ICH guidelines, the developed method efficiently quantified RN and DNP co-loaded in DQAsomes (121 nm) estimating matrix effect, release profile, entrapment efficiency, loading efficiency and in vivo plasma kinetics.

[Box: see text].