Treatment of alzheimer's disease with cholinesterase inhibitors

Synthesis, In Vitro Biological Evaluation and Molecular Modeling of Benzimidazole-Based Pyrrole/Piperidine Hybrids Derivatives as Potential Anti-Alzheimer Agents

Benzimidazole-based pyrrole/piperidine analogs (1-26) were synthesized and then screened for their acetylcholinesterase and butyrylcholinesterase activities. All the analogs showed good to moderate cholinesterase activities. Synthesized compounds (1-13) were screened in cholinesterase enzyme inhibition assays and showed AChE activities in the range of IC50 = 19.44 ± 0.60 µM to 36.05 ± 0.4 µM against allanzanthane (IC50 = 16.11 ± 0.33 µM) and galantamine (IC50 = 19.34 ± 0.62 µM) and varied BuChE inhibitory activities, with IC50 values in the range of 21.57 ± 0.61 µM to 39.55 ± 0.03 µM as compared with standard allanzanthane (IC50 = 18.14 ± 0.05 µM) and galantamine (IC50 = 21.45 ± 0.21 µM). Similarly, synthesized compounds (14-26) were also subjected to tests to determine their in vitro AChE inhibitory activities, and the results obtained corroborated that all the compounds showed varied activities in the range of IC50 = 22.07 ± 0.13 to 42.01 ± 0.02 µM as compared to allanzanthane (IC50 = 20.01 ± 0.12 µM) and galantamine (IC50 = 18.05 ± 0.31 µM) and varied BuChE inhibitory activities, with IC50 values in the range of 26.32 ± 0.13 to 47.03 ± 0.15 µM as compared to standard allanzanthane (IC50 = 18.14 ± 0.05 µM) and galantamine (IC50 = 21.45 ± 0.21 µM). Binding interactions of the most potent analogs were confirmed through molecular docking studies. The active analogs 2, 4, 10 and 13 established numerous interactions with the active sites of targeted enzymes, with docking scores of -10.50, -9.3, -7.73 and -7.8 for AChE and -8.97, -8.2, -8.20 and -7.6 for BuChE, respectively.

Polyphenol-enriched Desmodium elegans DC. ameliorate scopolamine-induced amnesia in animal model of Alzheimer's disease: In Vitro, In Vivo and In Silico approaches

The current study aims to quantify HPLC-DAD polyphenolics in the crude extracts of Desmodium elegans, evaluating its cholinesterase inhibitory, antioxidant, molecular docking and protective effects against scopolamine-induced amnesia in mice. A total of 16 compounds were identified which include gallic acid (239 mg g-1), p-hydroxybenzoic acid (11.2 mg g-1), coumaric acid (10.0 mg g-1), chlorogenic acid (10.88 mg g-1), caffeic acid (13.9 mg g-1), p-coumaroylhexose (41.2 mg g-1), 3-O-caffeoylquinic acid (22.4 mg g-1), 4-O-caffeoylquinic acid (6.16 mg g-1), (+)-catechin (71.34 mg g-1), (-)-catechin (211.79 mg g-1), quercetin-3-O-glucuronide (17.9 mg g-1), kaempferol-7-O-glucuronide (13.2 mg g-1), kaempferol-7-O-rutinoside (53.67 mg g-1), quercetin-3-rutinoside (12.4 mg g-1), isorhamnetin-7-O-glucuronide (17.6 mg g-1) and isorhamnetin-3-O-rutinoside (15.0 mg g-1). In a DPPH free radical scavenging assay, the chloroform fraction showed the highest antioxidant activity, with an IC50 value of 31.43 µg mL-1. In an AChE inhibitory assay, the methanolic and chloroform fractions showed high inhibitory activities causing 89% and 86.5% inhibitions with IC50 values of 62.34 and 47.32 µg mL-1 respectively. In a BChE inhibition assay, the chloroform fraction exhibited 84.36% inhibition with IC50 values of 45.98 µg mL-1. Furthermore, molecular docking studies revealed that quercetin-3-rutinoside and quercetin-3-O-glucuronide fit perfectly in the active sites of AChE and BChE respectively. Overall, the polyphenols identified exhibited good efficacy, which is likely as a result of the compounds' electron-donating hydroxyl groups (-OH) and electron cloud density. The administration of methanolic extract improved cognitive performance and demonstrated anxiolytic behavior among tested animals.

Antioxidant evaluation and computational prediction of prospective drug-like compounds from polyphenolic-rich extract of Hibiscus cannabinus L. seed as antidiabetic and neuroprotective targets: assessment through in vitro and in silico studies

BACKGROUND

Reports have implicated diabetes mellitus (DM) and Alzheimer's disease (AD) as some of the global persistent health challenges with no lasting solutions, despite of significant inputs of modern-day pharmaceutical firms. This study therefore, aimed to appraise the in vitro antioxidant potential, enzymes inhibitory activities, and as well carry out in silico study on bioactive compounds from polyphenolic-rich extract of Hibiscus cannabinus seed (PEHc).

METHODS

In vitro antioxidant assays were performed on PEHc using standard methods while the identification of phytoconstituents was carried out with high performance liquid chromatography (HPLC). For the in silico molecular docking using Schrodinger's Grid-based ligand docking with energetics software, seven target proteins were retrieved from the database ( https://www.rcsb.org/ ).

RESULTS

HPLC technique identified twelve chemical compounds in PEHc, while antioxidant quantification revealed higher total phenolic contents (243.5 ± 0.71 mg GAE/g) than total flavonoid contents (54.06 ± 0.09 mg QE/g) with a significant (p < 0.05) inhibition of ABTS (IC₅₀ = 218.30 ± 0.87 µg/ml) and 1, 1-diphenyl-2-picrylhydrazyl free radicals (IC₅₀ = 227.79 ± 0.74 µg/ml). In a similar manner, the extract demonstrated a significant (p < 0.05) inhibitory activity against α-amylase (IC₅₀ = 256.88 ± 6.15 µg/ml) and α-glucosidase (IC₅₀ = 183.19 ± 0.23 µg/ml) as well as acetylcholinesterase (IC₅₀ = 262.95 ± 1.47 µg/ml) and butyrylcholinesterase (IC₅₀ = 189.97 ± 0.82 µg/ml), respectively. Furthermore, In silico study showed that hibiscetin (a lead) revealed a very strong binding affinity energies for DPP-4, (PDB ID: 1RWQ) and α-amylase (PDB ID: 1SMD), gamma-tocopherol ( for peptide-1 receptor; PDB ID: 3C59, AChE; PDB ID: 4EY7 and BChE; PDB ID: 7B04), cianidanol for α-glucosidase; PDB ID: 7KBJ and kaempferol for Poly [ADP-ribose] polymerase 1 (PARP-1); PDB ID: 6BHV, respectively. More so, ADMET scores revealed drug-like potentials of the lead compounds identified in PEHc.

CONCLUSION

As a result, the findings of this study point to potential drug-able compounds in PEHc that could be useful for the management of DM and AD.

Cognitive Impairment in Older Adults and Oral Health Considerations: Treatment and Management

Current research aims at improving early detection and treatment of cognitive impairment (CI), particularly in patients at high risk for progression to dementia. It is important to treat signs and symptoms as early as possible to normalize quality of life. In older cognitively impaired patients, dentists and physicians should consider polypharmacy, uncontrolled cardiovascular risk factors, depression, metabolic or endocrine derangements, delirium due to intercurrent illness, and dementia, all of which may increase risk for CI and other negative outcomes. An interdisciplinary team approach is a necessity for a responsible and safe treatment sequence.

Bioassay Analysis and Molecular Docking Study Revealed the Potential Medicinal Activities of Active Compounds Polygonumins B, C and D from Polygonum minus (Persicaria minor)

Polygonumins B, C and D, derivative compounds of polygonumins A, were isolated from the stem of Polygonum minus. Based on NMR results, the structure of polygonumins derivatives is comprised of four phenylpropanoid units and a sucrose unit, with a similar structure to polygonumins A. However, the structural differences between polygonumins B (1), C (2) and D (3) can be distinguished based on the existence of methoxy, ethanoyl and hydroxyl groups and protons which bind to C-4, C-4′ and C-3″. Interestingly, these bioactive compounds showed various medicinal properties based on our investigation on antioxidant, anticholinesterase and anti-HIV-1 protease activities. The IC50 value of DPPH and ABTS (antioxidant activities) was in the following descending order: polygonumins B > polygonumins C > polygonumins A > polygonumins D. In addition, almost similar pattern of antioxidant activity was observed for anti-acetylcholinesterase activity based on its IC50 value in descending order: polygonumins B > polygonumins C > polygonumins D > polygonumins A. On the other hand, polygonumins C and D showed inhibition of HIV-1 protease activity more than the positive control, pepstatin A. Finally, molecular docking studies on AChE and BChE proteins were carried out in order to gain insight into the mode of interactions between these compounds and the active residues for both enzymes. These remarkable findings indicate that these compounds have potential to be developed as targeted drugs for Alzheimer’s disease or as anti-HIV drugs.

Isolation, crystal structure, DFT calculation and molecular docking of uncinatine-A isolated from Delphinium uncinatum

The main objective of our present research work was to explore molecular insight for potentially active new acetylcholinesterase inhibitor from the aerial parts of Delphinium uncinatum. New norditerpenoid alkaloids, uncinatine-A, was isolated from the basic alkaloidal fraction of D. uncinatum, based on bioactivity guided isolation. The structure of uncinatine-A was determined through latest spectroscopic techniques including single X-Ray diffraction technique. The structural data and electronic properties of uncinatine-A was also calculated by Density Functional Theory (DFT) using B3LYP/6-31þ G (p) basis set. The isolated natural product was evaluated for their acetyl cholinesterase inhibitory potential in dose dependent protocol (62.5-1000 μg/mL), followed by molecular docking studies. Significant competitive type inhibition activity (IC_{50 =} 207.73 ± 0.3) was shown by isolated natural norditerpenoid against cholinesterase targets in comparison with standard drugs available in the market such as galanthamine. The molecular docking results showed that isolated natural product was well accommodated by AChE in the active site with docking scores -11.0326. This is the first report indicating uncinatine-A as a potent acetylcholinesterase inhibitor and can be used as a target drug in cerebral dementia and Alzheimer diseases.

2-amino thiazole derivatives as inhibitors of some metabolic enzymes: An In Vitro and In Silico study

The thiazole derivatives are desirable compounds in the evaluation of their biological activities such as antiprotozoal antibacterial, antifungal, antituberculosis. Considering the medical application potential of 2-amino thiazole compounds, we aimed to determine the effects of 2-amino thiazole derivatives on the activities of carbonic anhydrase I-II isoenzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Among the chemicals we used in our study, 2-Amino-4-(4-chlorophenyl)thiazole compound exhibited the best inhibition against hCA I with K_i of 0.008±0.001 μM. The 2-Amino-4-(4-bromophenyl)thiazole compound exhibited the best inhibition against hCA II, AChE and BChE with K_i of 0.124±0.017 μM, 0.129±0.030 μM and 0.083±0.041 μM, respectively. Molecular docking analysis showed that compound 2-Amino-4-(5,6,7,8-tetrahydro-2-naphthyl)thiazole had the highest inhibitory potency against hCA I, hCA II, AChE, BChE with the estimated binding energy of -6.75 , -7.61, -7.86, -7.96 kcal/mol, respectively. This article is protected by copyright. All rights reserved.

Protective Effects of Inosine on Memory Consolidation in a Rat Model of Scopolamine-Induced Cognitive Impairment: Involvement of Cholinergic Signaling, Redox Status, and Ion Pump Activities

This study investigated the effects of inosine on memory acquisition and consolidation, cholinesterases activities, redox status and Na⁺, K⁺-ATPase activity in a rat model of scopolamine-induced cognitive impairment. Adult male rats were divided into four groups: control (saline), scopolamine (1 mg/kg), scopolamine plus inosine (50 mg/kg), and scopolamine plus inosine (100 mg/kg). Inosine was pre-administered for 7 days, intraperitoneally. On day 8, scopolamine was administered pre (memory acquisition protocol) or post training (memory consolidation protocol) on inhibitory avoidance tasks. The animals were subjected to the step-down inhibitory avoidance task 24 hours after the training. Scopolamine induced impairment in the acquisition and consolidation phases; however, inosine was able to prevent only the impairment in memory consolidation. Also, scopolamine increased the activity of acetylcholinesterase and reduced the activity of Na⁺, K⁺-ATPase and the treatment with inosine protected against these alterations in consolidation protocol. In the animals treated with scopolamine, inosine improved the redox status by reducing the levels of reactive oxygen species and thiobarbituric acid reactive substances and restoring the activity of the antioxidant enzymes, superoxide dismutase and catalase. Our findings suggest that inosine may offer protection against scopolamine-induced memory consolidation impairment by modulating brain redox status, cholinergic signaling and ion pump activity. This compound may provide an interesting approach in pharmacotherapy and as a prophylactic against neurodegenerative mechanisms involved in Alzheimer's disease.

Cognitive Impairment in Older Adults and Oral Health Considerations: Treatment and Management

Current research aims at improving early detection and treatment of cognitive impairment (CI), particularly in patients at high risk for progression to dementia. It is important to treat signs and symptoms as early as possible to normalize quality of life. In older cognitively impaired patients, dentists and physicians should consider polypharmacy, uncontrolled cardiovascular risk factors, depression, metabolic or endocrine derangements, delirium due to intercurrent illness, and dementia, all of which may increase risk for CI and other negative outcomes. An interdisciplinary team approach is a necessity for a responsible and safe treatment sequence.

Antioxidant properties of eugenol, butylated hydroxylanisole, and butylated hydroxyl toluene with key biomolecules relevant to Alzheimer's diseases-In vitro

This research work examined and likened effect of eugenol a natural phenolic compound with butylated hydroxylanisole (BHA) and butylated hydroxyl toluene (BHT) synthetic phenolic compounds with key biomolecules [acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and monoamine oxidase (MAO)] relevant to Alzheimer's diseases (AD) in vitro. Ten millimolar each sample was prepared in a mixture of ethanol and water (1:1 v/v), and the interactions with AChE, BChE, and MAO were evaluated. Still, ferric reducing antioxidant property, ABTS radicals scavenging ability and lipid peroxidation were carried out. The results revealed eugenol, BHT, and BHA inhibited AChE, BChE, and MAO activities dose-dependently. Though, eugenol had greater inhibitory effect against AChE and BChE activities. Also, eugenol demonstrated higher antioxidant potential compared to BHT and BHA. The potent enzymatic inhibitory and antioxidant effects of eugenol indicate eugenol could be promising as an alternative food additive and neuromodulator in AD management. PRACTICAL APPLICATION: BHT and BHA are synthetic antioxidant employed industrially as food preservative. BHT and BHA are employed in food packaging, drugs, and cosmetics. Although BHT and BHA are widely in use but have been found were associated with alteration in sleeping, induced changes in brain serotonin and norepinephrine levels with increased cholinesterase activity. Endocrine disrupting effects, reproductive disorder is more side effects associated with the use of BHT and BHA. However, eugenol a natural compound found in plants compares favorably with BHT and BHA as antioxidant with many more health promoting benefits such as neuroprotective effects, antiapoptotic effects, and prevent aluminum toxicity. Eugenol being a natural antioxidant with no side effects showing more promising effects over the synthetic phenolic compounds and could be an alternative for the BHT and BHA.

Inhibition of acetylcholinesterase and butyrylcholinesterase with uracil derivatives: kinetic and computational studies

Acetylcholinesterase (AChE) and Butyrylcholinesterase (BuChE) inhibitors are interesting compounds for different therapeutic applications, among which Alzheimer's disease. Here, we investigated the inhibition of these cholinesterases with uracil derivatives. The mechanism of inhibition of these enzymes was observed to be due to obstruction of the active site entrance by the inhibitors scaffold. Molecular docking and molecular dynamics (MD) simulations demonstrated the possible key interactions between the studied ligands and amino acid residues at different regions of the active sites of AChE and BuChE. Being diverse of the classical AChE and BuChE inhibitors, the investigated uracil derivatives may be used as lead molecules for designing new therapeutically effective enzyme inhibitors.

Antioxidant and Anticholinesterase Activities of Macrosphyra Longistyla (DC) Hiern Relevant in the Management of Alzheimer's Disease

Macrosphyra longistyla has been used in many traditional systems of medicine for its anti-hemorrhagic, antidiabetic, anti-ulcer, and anti-diarrhea properties. The acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitions of the crude methanol extracts and its various partitioned fractions were determined by a modified method of Ellman. An evaluation of the antioxidant activity was carried out using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging, ferric reducing power, and nitric oxide scavenging assays. The total flavonoids were estimated based on the aluminum chloride method, while the total tannins and phenolics were estimated based on the vanillin-HCl and Folin-Ciocalteu method, respectively. The ethyl acetate fraction had the highest DPPH radical scavenging activity, and the highest ferric reducing power with a concentration providing 50% inhibition (IC₅₀) of 0.079 mg/mL and 0.078 mg/mL, respectively, while the crude methanol extract had the highest nitric oxide scavenging activity with an IC₅₀ of 0.008 mg/mL. The methanol extract had the highest phenolics and flavonoids contents, while the aqueous fraction had the highest tannin content. The crude methanol extract had the best AChE and BuChE inhibitory action, with an IC₅₀ of 0.556 µg/mL and 5.541 µg/mL, respectively, suggesting that the plant had a better AChE inhibiting potential. A moderate correlation was observed between the phenolic content and DPPH radical scavenging, NO radical scavenging, and AChE inhibitory activities (r² = 0.439, 0.430, and 0.439, respectively), while a high correlation was seen between the flavonoid content and these activities (r² = 0.695, 0.724, and 0.730, respectively), and the ferric reducing antioxidant power correlated highly with the proautocyanidin content (r² = 0.801). Gas chromatography mass spectrometry (GCMS) revealed decanoic acid methyl ester (24.303%), 11,14-eicosadienoic acid methyl ester (16.788%), linoelaidic acid (10.444%), pentadecanoic acid (9.300%), and 2-methyl-hexadecanal (9.285%). Therefore, we suggest that M. longistyla contain bioactive chemicals, and could be a good alternative for the management of Alzheimer's and other neurodegenerative diseases.

Metabolite Profiling by Hyphenated Liquid Chromatographic Mass Spectrometric Technique (HPLC-DAD-ESI-Q-TOF-MS/MS) and Neurobiological Potential of Haplophyllum sahinii and H. vulcanicum Extracts

In the current study, the ethanol extracts of flower, stem, and root parts of two endemic Turkish species, e. g., Haplophyllum sahinii O. Tugay & D. Ulukuş and H. vulcanicum Boiss. & Heldr., were screened against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) associated with Alzheimer's disease as well as tyrosinase (TYR) linked to Parkinson's disease using ELISA microplate assay at 200 μg/mL. Among the extracts, the highest inhibition was caused by the stem extract of H. sahinii against BChE (IC₅₀ =64.93±1.38 μg/mL). Consistently, all of the extracts were found to exert a selective inhibition towards BChE to some extent. It was only the root extract of H. vulcanicum that could inhibit AChE at low level (IC₅₀ =203.18±5.33 μg/mL). None of the extracts displayed an inhibition over 50 % against TYR. Metabolite profiling of the extracts was achieved by a highly hyphenated liquid chromatographic mass spectrometric technique (HPLC-DAD-ESI-Q-TOF-MS/MS), which revealed the presence of furoquinoline (β-fagarine, γ-fagarine) and amide (tubasenicine, tubacetine) alkaloids; furano- (rutamarin), pyrano- (xanthyletine), and geranyloxy coumarins; phenylpropanoid (secoisolariciresinol), arylnaphthalene (mono-O-acetyldiphyllin apioside), and dibenzylbutyrolactone (kusunokinin, haplomyrfolin) lignans. Several important differences were observed between the extracts analyzed. β-Fagarine was the major alkaloid in H. vulcanicum, whereas γ-fagarine was present only in the roots of both Haplophyllum species; moreover, secoisolariciresinol and secoisolariciresinol dimethyl ether were the main lignans in the stems and flowers. This is the first study identifying ChE and TYR inhibitory effect and metabolic profiles of H. vulcanicum and H. sahinii.

Flavonoids as Prospective Neuroprotectants and Their Therapeutic Propensity in Aging Associated Neurological Disorders

Modern research has revealed that dietary consumption of flavonoids and flavonoids-rich foods significantly improve cognitive capabilities, inhibit or delay the senescence process and related neurodegenerative disorders including Alzheimer’s disease (AD). The flavonoids rich foods such as green tea, cocoa, blue berry and other foods improve the various states of cognitive dysfunction, AD and dementia-like pathological alterations in different animal models. The mechanisms of flavonoids have been shown to be mediated through the inhibition of cholinesterases including acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), β-secretase (BACE1), free radicals and modulation of signaling pathways, that are implicated in cognitive and neuroprotective functions. Flavonoids interact with various signaling protein pathways like ERK and PI3-kinase/Akt and modulate their actions, thereby leading to beneficial neuroprotective effects. Moreover, they enhance vascular blood flow and instigate neurogenesis particularly in the hippocampus. Flavonoids also hamper the progression of pathological symptoms of neurodegenerative diseases by inhibiting neuronal apoptosis induced by neurotoxic substances including free radicals and β-amyloid proteins (Aβ). All these protective mechanisms contribute to the maintenance of number, quality of neurons and their synaptic connectivity in the brain. Thus flavonoids can thwart the progression of age-related disorders and can be a potential source for the design and development of new drugs effective in cognitive disorders.

Ambroxol as a novel disease-modifying treatment for Parkinson's disease dementia: protocol for a single-centre, randomized, double-blind, placebo-controlled trial

BACKGROUND

Currently there are no disease-modifying treatments for Parkinson's disease dementia (PDD), a condition linked to aggregation of the protein α-synuclein in subcortical and cortical brain areas. One of the leading genetic risk factors for Parkinson's disease is being a carrier in the gene for β-Glucocerebrosidase (GCase; gene name GBA1). Studies in cell culture and animal models have shown that raising the levels of GCase can decrease levels of α-synuclein. Ambroxol is a pharmacological chaperone for GCase and is able to raise the levels of GCase and could therefore be a disease-modifying treatment for PDD. The aims of this trial are to determine if Ambroxol is safe and well-tolerated by individuals with PDD and if Ambroxol affects cognitive, biochemical, and neuroimaging measures.

METHODS

This is a phase II, single-centre, double-blind, randomized placebo-controlled trial involving 75 individuals with mild to moderate PDD. Participants will be randomized into Ambroxol high-dose (1050 mg/day), low-dose (525 mg/day), or placebo treatment arms. Assessments will be undertaken at baseline, 6-months, and 12-months follow up times. Primary outcome measures will be the Alzheimer's disease Assessment Scale-cognitive subscale (ADAS-Cog) and the ADCS Clinician's Global Impression of Change (CGIC). Secondary measures will include the Parkinson's disease Cognitive Rating Scale, Clinical Dementia Rating, Trail Making Test, Stroop Test, Unified Parkinson's disease Rating Scale, Purdue Pegboard, Timed Up and Go, and gait kinematics. Markers of neurodegeneration will include MRI and CSF measures. Pharmacokinetics and pharmacodynamics of Ambroxol will be examined through plasma levels during dose titration phase and evaluation of GCase activity in lymphocytes.

DISCUSSION

If found effective and safe, Ambroxol will be one of the first disease-modifying treatments for PDD.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02914366, 26 Sep 2016/retrospectively registered.

Memory enhancing, anticholinesterase and antimicrobial activities of β-phenylnitroethane and essential oil of Dennettia tripetala Baker f

ETHNOPHARMACOLOGICAL RELEVANCE

Dennettia tripetala Baker f. belonging to the family Annonaceae is an important food and medicinal plant used in some local communities in Southwest Nigeria.

AIMS OF THE STUDY

The study aims at determining the chemical composition of the essential oil of different morphological parts of D. tripetala, the memory enhancing and anticholinesterase activities as well as the antimicrobial properties.

MATERIALS AND METHODS

Essential oil of the morphological parts namely the fresh fruits, dried fruits, dried seeds and fresh leaves were obtained by hydrodistillation and analysed by GC-FID and GC-MS. The oil samples were evaluated for memory enhancement using Y-maze and in vitro anticholinesterase activities. The antimicrobial properties were also evaluated by nutrient broth method.

RESULTS

GC analysis identifies β-ocimene, linalool, β-phenylnitroethane and humulene as common constituents of the fresh fruits, dried fruits, dried seeds and fresh leaves. β-Phenylnitroethane (BPNE) was the predominant constituent of all the parts; with the dried seed containing 87.4% BPNE, followed by the dried fruit (78.1%), fresh leaf (62.9%) and the fresh fruit content was 61.6%. The second most predominant constituent, linalool, was highest in the fresh fruit (29.9%), followed by the fresh leaf (16.0%), the dried fruit (14.9%) and the dried seed had least linalool content (8.8%). (Z)- β-Ocimene and humulene were other common components. The seed oil and BPNE exhibited high memory enhancing activities in the Y-maze test. However, the seed oil exhibited the best inhibition against the test bacteria and it had a broad spectrum of antimicrobial activity. Bioactivities demonstrated by the various essential oils were not solely due to BPNE; rather, synergistic effects of other components are quite obvious.

CONCLUSION

The most abundant component - β-phenylnitroethane of D. tripetala was totally responsible for its memory enhancing properties but could not solely account for its antimicrobial activity.

Pharmacologic management of behavioral and psychological symptoms of major neurocognitive disorder

Behavioral and psychological symptoms of dementia (BPSD) occur in approximately 80% of patients who receive a diagnosis of major neurocognitive disorder. Nonpharmacologic strategies are the first-line treatment for BPSD. However, psychotropic medications are often necessary when nonpharmacologic methods are not effective in treating symptoms that are distressing or are causing behaviors that are dangerous to the patient or the patient's caregivers. The article provides a review of evidence-based recommendations for the use of antipsychotics, cognitive enhancers, and serotonin reuptake inhibitors for the treatment of BPSD. Different pharmacologic approaches are demonstrated through 2 patient cases in which nonpharmacologic management was not effective. The severity of BPSD must be weighed against the risks and benefits of pharmacologic intervention in order to implement an optimal medication regimen.

Chromatographic fingerprint analysis, antioxidant properties, and inhibition of cholinergic enzymes (acetylcholinesterase and butyrylcholinesterase) of phenolic extracts from Irvingia gabonensis (Aubry-Lecomte ex O'Rorke) Baill bark

BACKGROUND

Irvingia gabonensis stem bark is a medicinal plant used in most parts of Africa to manage a number of ailments including neurodegenerative diseases that occur without scientific basis. This work characterized the phenolic composition, evaluated the cholinergic enzymes (acetylcholinesterase, AChE and butyrylcholinesterase, BChE) inhibition, and assessed the antioxidant activity of phenolic extracts from I. gabonensis (Aubry-Lecomte ex O'Rorke) Baill bark.

METHODS

Total phenol and flavonoids content was evaluated in addition to antioxidant activity as shown by Fe2+ chelation, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability, and 2,2-azino-bis-(3-ethylbenthiazoline-6-sulfonic acid) (ABTS) radical scavenging ability. Inhibitory activities on AChE and BChE were evaluated.

RESULTS

The extract was found to be rich in phenolic acid (ellagic acid) and flavonoids (quercetrin, kaempferol, and apigenin). The phenolic extracts displayed DPPH radical scavenging ability (IC50=19.98 μg/mL), ABTS radical scavenging ability (IC50=18.25 μg/mL), iron chelation (IC50=113.10 μg/mL), and reducing power (Fe3+ to Fe2+) (5.94 mg ascorbic acid equivalent/100 g). Extracts of I. gabonensis inhibited AChE (IC50=32.90 μg/mL) and BChE (IC50=41.50 μg/mL) activities in concentration-dependent manner.

CONCLUSIONS

Hence, possible mechanism through which the stem bark executes their anti-Alzheimer's disease activity might be by inhibiting cholinesterase activities in addition to suppressing oxidative-stress-induced neurodegeneration.

Aqueous extract of Securidaca longipendunculata Oliv. and Olax subscropioidea inhibits key enzymes (acetylcholinesterase and butyrylcholinesterase) linked with Alzheimer's disease in vitro

CONTEXT

Plants have historically been used to treat neurodegerative diseases which include Alzheimer's disease.

OBJECTIVE

This study investigated the antioxidant properties and inhibitory effect of aqueous extracts of Securidaca longipendunculata root and Olax subscropioidea leaf on the cholinergic system in rat brain in vitro.

MATERIALS AND METHODS

Aqueous extracts (1:20 w/v) of S. longipendunculata root and O. subscropioidea leaf was prepared and the ability of the extract to inhibit the activities of acetylcholinesterase and butyrylcholinesterase was evaluated as well as antioxidants as typified by 2,2-azino-bis-(3-ethylbenthiazoline-6-sulphonic acid (ABTS^•) radical scavenging ability and Fe chelation spectophotometrically.

RESULTS

ABTS^• radical scavenging ability showed that S. longipendunculata (0.075 Mmol TEAC/100 g) had a higher scavenging ability than O. subscropioidea (0.07 Mmol TEAC/100 g). Also, the Fe²⁺chelating ability of both extracts revealed that S. longipendunculata (IC₅₀=105.57 g/mL) had a significantly (p < 0.05) higher Fe²⁺chelating ability than O. subscropioidea (IC₅₀=255.84 g/mL). Extracts of S. longipendunculata and O. subscropioidea inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities. However, S. longipendunculata (IC₅₀=108.02 g/mL) has the higher AChE inhibitory activity than O. subscropioidea (IC₅₀=110.35 g/mL). Also, both extracts inhibit BChE activity in vitro but S. longipendunculata (IC₅₀=82.55 g/mL) had a higher BChE inhibitory activity than O. subscropioidea (IC₅₀=108.44 g/mL).

DISCUSSION AND CONCLUSIONS

The mechanism by which S. longipendunculata root and O. subscropioidea leaf perform their anti-Alzheimer's disease activity may be by their inhibition on the key enzymes linked to this disease.

New anthrarobin acyl derivatives as butyrylcholinesterase inhibitors: synthesis, in vitro and in silico studies

To treat Alzheimer's disease (AD), the available candidates are effective only against mild AD or have side effects. So, a study was planned to synthesis new candidates that may have good potential to treat AD. A series of new anthrarobin acyl derivatives (2–8) were synthesized by the reaction of anthrarobin (1) and acetic anhydride/acyl chlorides. The product were characterized by ¹H NMR and EI-MS, and evaluated for butyrylcholinesterase (BuChE) inhibition activity. Compounds 5 and 4 showed notable BuChE inhibitory potential with IC₅₀ 5.3 ± 1.23 and 17.2 ± 0.47 μM, respectively when compared with the standard eserine (IC₅₀ 7.8 ± 0.27 μM), compound 5 showed potent BuChE inhibition potential than the standard eserine. The active compounds 5 and 4 have acyl groups at 2-OH and 10-OH positions which may be responsible for inhibitory potential as this orientation is absent in other products. In silico studies of 5 and 4 products revealed the high inhibitory potential due to stable binding of ligand with the BuChE active sites with docking energy score −18.8779 kcal/mol and −23.1159 kcal/mol, respectively. Subsequently, compound 5 that have potent BuChE inhibitory activity could be the potential candidate for drug development for Alzheimer’s disease.

Statistical properties of continuous composite scales and implications for drug development

Little research has been conducted on the statistical properties of composite measures comprising linear combinations of continuous component scales. We assessed the quantitative relationship between the composites and their individual components regarding their abilities to detect treatment effects. In particular, we developed the mathematical derivation of the treatment effect size of a continuous composite in relation to the treatment effect sizes of its components and proved multiple properties of the composite. We demonstrated that the treatment effect size of a composite is greater than the minimum treatment effect size of its components and that above certain thresholds of correlations of components and ratios of component effect sizes, the composite may outperform its components. Examples from Alzheimer's disease (AD) clinical studies of solanezumab and donepezil using the composite Integrated AD Rating Scale (iADRS) and its components, the AD Assessment Scale-Cognitive subscale (ADAS-Cog) and AD Cooperative Study-Activities of Daily Living inventory, instrumental items (ADCS-iADL) were consistent with the theoretical statistical properties. The understanding of the quantitative relationships between continuous composites and their components will be useful in clinical trial design and the development of new scales and composites across therapeutic areas.

Function and clinical meaningfulness of treatments for mild Alzheimer's disease

Introduction

Effectiveness of Alzheimer's disease (AD) treatments is commonly evaluated with coprimary outcomes; cognition with function to ensure clinical meaningfulness of a cognitive effect.

Methods

We reviewed the literature for functional outcomes in mild AD or mild cognitive impairment (MCI) patients (distinct from combined mild-moderate/severe AD) treated with approved AD drugs. Cognitive and functional treatment differences in mild AD patients in solanezumab EXPEDITION/EXPEDITION2 studies were compared across time.

Results

Seven publications provided MCI/mild AD functional outcomes, one of which reported a significant functional treatment effect. Secondary analyses of EXPEDITION studies suggested a smaller functional effect of solanezumab relative to cognition. An increasing effect of solanezumab over 18 months was shown for cognition and function.

Discussion

Function as the sole measure to demonstrate clinical meaningfulness of cognitive effects in mild AD may have limitations. For disease-modifying treatments, point differences on cognitive and functional scales should be qualified with duration of treatment.

Comparative chemical profiling, cholinesterase inhibitions and anti-radicals properties of essential oils from Polygonum hydropiper L: a preliminary anti- Alzheimer's study

Background

Cholinesterase inhibition is a vital target for the development of novel and mechanism based inhibitors, owing to their role in the breakdown of acetylcholine (ACh) neurotransmitter to treat various neurological disorders including Alzheimer’s disease (AD). Similarly, free radicals are implicated in the progression of various diseases like neurodegenerative disorders. Due to lipid solubility and potential to easily cross blood brain barrier, this study was designed to investigate the anticholinesterase and antioxidant potentials of the standardized essential oils from the leaves and flowers of Polygonum hydropiper.

Methods

Essential oils from the leaves (Ph.LO) and flowers (Ph.FO) of P. hdropiper were isolated using Clevenger apparatus. Oil samples were analyzed by GC-MS to identify major components and to attribute the antioxidant and anticholinesterase activity to specific components. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potentials of the samples were determined following Ellman’s assay. Antioxidant assays were performed using 1,1-diphenyl,2-picrylhydrazyl (DPPH), 2,2-azinobis[3-ethylbenzthiazoline]-6-sulfonic acid (ABTS) and hydrogen peroxide (H₂O₂) free radical scavenging assays.

Results

In the GC-MS analysis 141 and 122 compounds were indentified in Ph.LO and Ph.FO respectively. Caryophylene oxide (41.42 %) was the major component in Ph.FO while decahydronaphthalene (38.29 %) was prominent in Ph.LO. In AChE inhibition, Ph.LO and Ph.FO exhibited 87.00** and 79.66***% inhibitions at 1000 μg/ml with IC₅₀ of 120 and 220 μg/ml respectively. The IC₅₀ value for galanthamine was 15 μg/ml. In BChE inhibitory assay, Ph.LO and Ph.FO caused 82.66*** (IC₅₀ 130 μg/ml) and 77.50***% (IC₅₀ 225 μg/ml) inhibitions respectively at 1000 μg/ml concentration. In DPPH free radical scavenging assay, Ph.LO and Ph.FO exhibited IC₅₀ of 20 and 200 μg/ml respectively. The calculated IC₅₀s were 180 & 60 μg/ml for Ph.LO, and 45 & 50 μg/ml for Ph.FO in scavenging of ABTS and H₂O₂ free radicals respectively.

Conclusions

In the current study, essential oils from leaves and flowers of P. hydropiper exhibited dose dependent anticholinesterase and antioxidant activities. Leaves essential oil were more effective and can be subjected to further in-vitro and in-vivo anti-Alzheimer’s studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-015-0145-8) contains supplementary material, which is available to authorized users.

Phenolic, flavonoid contents, anticholinesterase and antioxidant evaluation of Iris germanica var; florentina

This study was designed to investigate antioxidant and anticholinesterase potential of Iris germanica var; florentina. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential of plant samples were investigated by Ellman's assay. Antioxidant activity was performed using DPPH, H2O2 and ABTS free radical scavenging assays. Total phenolics and flavonoids contents were expressed in mg GAE/g dry weight and mg RTE/g, respectively. In AChE inhibition assay, Ig.Fl, Ig.Sp and Ig.Cf fractions exhibited highest activity with IC50 values of < 0.1, 5.64 and 19 μg/mL, respectively. In BChE inhibitory assay, Ig.Fl, Ig.Sp, Ig.Cf and Ig.Cr were most active with IC50 of < 0.1, < 0.1, 31 and 78 μg/mL, respectively. In DPPH assay, Ig.Fl and Ig.Cf exhibited highest inhibition of free radicals, 80.52% (IC50 = 9 μg/mL) and 78.30% (IC50 = 8 μg/mL), respectively. In ABTS assay Ig.Cr, Ig.Cf, Ig.Fl and Ig.Sp exhibited IC50 values of < 0.1, 2, 2 and 3 μg/mL, respectively.

Anticholinesterase and Antioxidative Properties of Aqueous Extract of Cola acuminata Seed In Vitro

Background. Cola acuminata seed, a commonly used stimulant in Nigeria, has been reportedly used for the management of neurodegenerative diseases in folklore without scientific basis. This study sought to investigate the anticholinesterase and antioxidant properties of aqueous extracts from C. acuminata seed in vitro. Methodology. The aqueous extract of C. acuminata seed was prepared (w/v) and its effect on acetylcholinesterase (AChE) and butyrylcholinesterase activities, as well as some prooxidant (FeSO₄, sodium nitroprusside (SNP), and quinolinic acid (QA)) induced lipid peroxidation in rat brain in vitro, was investigated. Results. The results revealed that C. acuminata seed extract inhibited AChE (IC₅₀ = 14.6 μg/mL) and BChE (IC₅₀ = 96.2 μg/mL) activities in a dose-dependent manner. Furthermore, incubation of rat's brain homogenates with some prooxidants caused a significant increase P < 0.05 in the brain malondialdehyde (MDA) content and inhibited MDA production dose-dependently and also exhibited further antioxidant properties as typified by their high radicals scavenging and Fe²⁺ chelating abilities. Conclusion. Inhibition of AChE and BChE activities has been the primary treatment method for mild Alzheimer's disease (AD). Therefore, one possible mechanism through which the seed exerts its neuroprotective properties is by inhibiting cholinesterase activities as well as preventing oxidative-stress-induced neurodegeneration. However, this is a preliminary study with possible physiological implications.

Treatment effects in multiple cognitive domains in Alzheimer's disease: a two-year cohort study

Introduction

Despite widespread use of second-generation cholinesterase inhibitors for the symptomatic treatment of Alzheimer’s disease (AD), little is known about the long term effects of cholinergic treatment on global cognitive function and potential specific effects in different cognitive domains. The objectives of this study were to determine the association between cholinergic treatment and global cognitive function over one and two years in a cohort of patients with mild or moderate AD and identify potential differences in domain-specific cognitive outcomes within this cohort.

Methods

A cohort of patients meeting the revised National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria for mild or moderate AD, including patients both on treatment with a cholinesterase inhibitor and untreated controls (treated = 65, untreated = 65), were recruited from the Cognitive Neurology Clinic at Sunnybrook Health Sciences Centre, as part of the Sunnybrook Dementia Study. Patients were followed for one to two years and underwent standardized neuropsychological assessments to evaluate global and domain-specific cognitive function. Associations between cholinesterase inhibitor use and global and domain-specific cognitive outcome measures at one and two years of follow-up were estimated using mixed model linear regression, adjusting for age, education, and baseline mini mental state examination (MMSE).

Results

At one year, treated patients showed significantly less decline in global cognitive function, and treatment and time effects across tests of executive and visuospatial function. At two years, there was a significant trend towards less decline in global cognition for treated patients. Moreover, treated patients showed significant treatment and time effects across tests of executive functioning, memory, and visuospatial function.

Conclusions

The present study offers two important contributions to knowledge of the effectiveness of cholinesterase inhibitor treatment in patients with mild-moderate AD: 1) that second-generation cholinesterase inhibitors demonstrate long-term effectiveness for reducing global cognitive decline over one to two years of follow-up, and 2) that decline in function for cognitive domains, including executive function, memory, and visuospatial skill that are primarily mediated by frontal networks and by the cholinergic system, rather than memory, may be slowed by treatment targeting the cholinergic system.

Phenolic contents, antioxidant and anticholinesterase potentials of crude extract, subsequent fractions and crude saponins from Polygonum hydropiper L

BACKGROUND

We investigated Polygonum hydropiper L. (P. hydropiper) for phenolic contents, antioxidant, anticholinesterase activities, in an attempt to rationalize its use in neurological disorders.

METHODS

Plant crude extract (Ph.Cr), its subsequent fractions: n-hexane (Ph.Hex), chloroform (Ph.Chf), ethyl acetate (Ph.EtAc), n-Butanol (Ph.Bt), aqueous (Ph.Aq) and saponins (Ph.Sp) were evaluated for 1,1-diphenyl,2-picrylhydrazyl (DPPH), 2,2-azinobis[3-ethylbenzthiazoline]-6-sulfonic acid (ABTS) free radical scavenging potential. Further, acetylcholinesterase (AChE) & butyrylcholinesterase (BChE) inhibitory activities were performed using Ellman's assay. Moreover, total phenolic contents of plant extracts were determined and expressed in mg of gallic acid equivalent per gram of dry sample (mg GAE/g dry weight).

RESULTS

Among different fractions, Ph.Cr (90.82), Ph.Chf (178.16), Ph.EtAc (203.44) and Ph.Bt (153.61) exhibited high phenolic contents. All fractions showed concentration dependent DPPH scavenging activity, with Ph.EtAc 71.33% (IC50 15 μg/ml), Ph.Bt 71.40% (IC50 3 μg/ml) and Ph.Sp 71.40% (IC50 35 μg/ml) were most potent. The plant extracts exhibited high ABTS scavenging ability i.e. Ph.Bt (91.03%), Ph.EtAc (90.56%), Ph.Sp (90.84%), Ph.Aq (90.56%) with IC50<0.01 μg/ml. All fractions showed moderate to high AChE inhibitory activity as; Ph.Cr, 86.87% (IC50 330 μg/ml), Ph.Hex, 87.49% (IC50 35 μg/ml), Ph.Chf, 84.76% (IC50 55 μg/ml), Ph.Sp, 87.58% (IC50 108 μg/ml) and Ph.EtAc 79.95% (IC50 310 μg/ml) at 1 mg/ml). Furthermore the BChE inhibitory activity was most prominent in Ph.Hex 90.30% (IC50 40 μg/ml), Ph.Chf 85.94% (IC50 215 μg/ml), Ph.Aq 87.62% (IC50 3 μg/ml) and Ph.EtAc 81.01% (IC50 395 μg/ml) fractions.

CONCLUSIONS

In this study, for the first time, we determined phenolic contents, isolated crude saponins, investigated antioxidant and anticholinestrase potential of P. hydropiper extracts. The results indicate that P. hydropiper is enriched with potent bioactive compounds and warrant further investigation by isolation and structural elucidation to find novel and affordable compounds for the treatment of various neurological disorders.

A preliminary investigation of anticholinesterase activity of some Iranian medicinal plants commonly used in traditional medicine

BACKGROUND

The aim of this study was to evaluate acetylcholinesterase inhibitory activity of some commonly used herbal medicine in Iran to introduce a new source for management of Alzheimer's disease. A total of 18 aqueous-methanolic extract (1:1; v/v) from the following plants: Brassica alba, Brassica nigra, Camellia sinensis, Cinchona officinalis, Citrus aurantifolia, Citrus x aurantium, Ferula assafoetida, Humulus lupulus, Juglans regia, Juniperus sabina, Myristica fragrans, Pelargonium graveolens, Pistacia vera, Punica granatum, Rheum officinale, Rosa damascena, Salix alba, and Zizyphus vulgaris were prepared and screened for their acetylcholinesterase inhibitory activity using in vitro Ellman spectrophotometric method.

RESULTS

According to the obtained results, the order of inhibitory activity (IC50 values, μg /ml) of extracts from highest to the lowest was: C. sinensis (5.96), C. aurantifolia (19.57), Z. vulgaris (24.37), B. nigra (84.30) and R. damascena (93.1).

CONCLUSIONS

The results indicated and confirmed the traditional use of these herbs for management of central nervous system disorders. C. sinensis showed the highest activity in inhibition of acetylcholinesterase. However, further investigations on identification of active components in the extracts are needed.

Flavoring extracts of Hemidesmus indicus roots and Vanilla planifolia pods exhibit in vitro acetylcholinesterase inhibitory activities

Acetylcholinesterase inhibitors (AChEIs) are important for treatment of Alzheimer's disease and other neurological disorders. Search for potent and safe AChEIs from plant sources still continues. In the present work, we explored fragrant plant extracts that are traditionally used in flavoring foods, namely, Hemidesmus indicus and Vanilla planifolia, as possible sources for AChEI. Root and pod extracts of H. indicus and V. planifolia, respectively, produce fragrant phenolic compounds, 2-hydroxy-4-methoxybenzaldehyde (MBALD) and 4-hydroxy-3-methoxybenzaldehyde (vanillin). These methoxybenzaldehydes were shown to have inhibitory potential against acetylcholinesterase (AChE). Vanillin (IC50 = 0.037 mM) was detected as more efficient inhibitor than MBALD (IC50 = 0.047 mM). This finding was supported by kinetic analysis. Thus, plant-based food flavoring agents showed capacity in curing Alzheimer's disease and other neurological dysfunctions.

Dietary supplementation with Salvia sahendica attenuates acetylcholinesterase activity and increases mitochondrial transcription factor A and antioxidant proteins in the hippocampus of amyloid beta-injected rats

OBJECTIVES

We evaluated the acetylcholinesterase (AChE) inhibitory and potential antioxidant effects of Salvia sahendica extract to investigate whether these molecules are involved in learning and memory improvement in rats injected with fibrillar amyloid beta (Aβ) peptide in the CA1 region of their hippocampus.

METHODS

Rats were fed with S. sahendica (100 mg/kg/day) for 1 week before Aβ injection. Western blot analysis and enzymatic assays were carried out 7 days after injections.

KEY FINDINGS

Our results indicated that S. sahendica extract decreased AChE activity. Besides, S. sahendica prevented reduction in the level of nuclear respiratory factor-1 and mitochondrial transcription factor A (TFAM). Our data indicated the lack of sensitivity in citrate synthase and reduction in the activity of malate dehydrogenase in the presence of Aβ that was prevented with S. sahendica consumption. Pretreatment with S. sahendica extract impeded reduction of glutathione redox ratio, catalase and superoxide dismutase activity, while decreased the malondialdehyde level.

CONCLUSIONS

Based on the importance of AChE activity inhibition and increased TFAM level in the prevention of cognitive impairment, the use of S. sahendica could open a new protective issue in therapeutic fields of neurodegenerative disease.

Inhibition of acetylcholinesterase activities and some pro-oxidant induced lipid peroxidation in rat brain by two varieties of ginger (Zingiber officinale)

Ginger has been reportedly used for the management or treatment of Alzheimer's disease in folklore medicine. Therefore, this study sought to investigate the inhibitory effects of water extractable phytochemicals of red and white ginger on acetylcholinesterase activities, and sodium nitroprusside (SNP) and quinolinic acid (QA)-induced lipid peroxidation in rat brain -in vitro. Both extracts inhibited acetylcholinesterase (AChE) activities in a dose-dependent manner; however, white ginger had higher acetylcholinesterase inhibitory activity than red ginger. Combination of the ginger inhibited acetylcholinesterase activities synergistically. Furthermore, SNP and QA caused a significant increase in the malondialdehyde (MDA) contents of the brain; however, the extracts significantly decrease the SNP and QA elevated brain MDA contents in a dose-dependent manner. Nevertheless, there was no significant difference (P>0.05) in the inhibition of the SNP and QA-induced lipid peroxidation by both extracts. The inhibitory effect of ginger extracts on acetylcholinesterase activities and some prooxidants induced lipid peroxidation in rat's brain could be attributed to the presence of phytochemicals such as flavonoids, tannins, alkaloids and terpenoids. Therefore, some possible mechanism by which ginger extracts exert anti-Alzheimer properties could be through the inhibition of acetylcholinesterase activities and prevention of lipid peroxidation in the brain.

Inhibitory effect of some tropical green leafy vegetables on key enzymes linked to Alzheimer's disease and some pro-oxidant induced lipid peroxidation in rats' brain

This study sought to investigate the inhibitory effect of some commonly consumed Nigerian green leafy vegetables (raw and blanched) on acetylcholinesterase and butyrylcholinesterase (key enzyme linked to Alzheimer's disease) activities and some pro-oxidants (FeSO4, Sodium nitroprusside and Quinolinic acid) induced lipid peroxidation in rat brain in vitro. Three commonly consumed green leafy vegetables in Nigeria [Amarantus cruentus (Arowojeja), Struchium sparganophora (Ewuro-odo) and Telfairia occidentalis (Ugwu] were blanched in hot water for 10 min, and the extracts of the raw and blanched vegetables were prepared and used for subsequent analysis. The result revealed that all the vegetables inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity as well as the pro-oxidants induced lipid peroxidation in rat brain in a dose dependent manner; however, Amarantus cruentus extract (EC50 = 97.9 μg/ml) had the highest inhibitory effect on acetylcholinesterase activity while Telfairia occidentalis extract (EC50 = 52.7 μg/ml) had the highest inhibitory effect on butyrylcholinesterase activity. However, blanching of the vegetables caused a significant (P < 0.05) decrease in the inhibitory effect of the vegetables on AChE activities while it enhanced the inhibition of the pro-oxidants induced lipid peroxidation in rat brain in vitro. Therefore, some of the possible mechanism by which green leafy vegetables exert their neuroprotective activities could be through the inhibition of acetylcholinesterase and butyrylcholinesterase activities and prevention of lipid peroxidation in the brain. However, blanching of the vegetables could reduce their ability to inhibit acetylcholinesterase and butyrylcholinesterase activity.

Cholinergic influence on memory stages: A study on scopolamine amnesic mice

Objectives:

The study was planned to determine cholinergic influence on different stages of memory - acquisition, consolidation and recall in scopolamine-induced amnesia (memory impairment) in mice.

Materials and Methods:

To study acquision, consolidation and recall stages of memory, we administered scopolamine (0.75, 1.5 and 3 mg/kg ip) 30 minutes and five minutes prior to first trial acquisition and consolidation and 30 minutes prior to second trial recall of passive avoidance (PA) test, respectively, in separate groups. Tacrine (5 mg/kg po) and rivastigmine (5 mg/kg po) were administered one hour prior to first trial in separate groups which received scopolamine (3 mg/kg ip) 30 minutes and five minutes prior to first trial where as the control group received vehicle only.

Results:

In the control group, there was a significant (P < 0.01) increase in transfer latency time (TLT) in the second trial compared to first indicating successful learning. In scopolamine treated groups, administering scopolamine 30 minutes or five minutes prior to first trial did not show any significant (P > 0.05) change in TLT whereas mice treated with scopolamine 30 minutes prior to second trial showed significant (P < 0.01) increase in TLT in second trial as compared to the first. Both tacrine and rivastigmine administration in scopolamine treated mice showed significant (P < 0.05-0.01) increase in TLT in second trial as compared to first trial while the rivastigmine treated group showed greater percentage retention compared to tacrine treated group.

Conclusion:

Results show that acquisition and consolidation are more susceptible to the scopolamine effects than recall. Thus, it may be concluded that cholinergic influence is more on acquisition and consolidation as compared to recall.

Anticholinesterase activity of endemic plant extracts from Soqotra

A total of 30 chloroform and methanol extracts from the following endemic Soqotran plants Acridocarpus socotranus Olive, Boswellia socotranao Balf.fil, Boswellia elongata Balf. fil., Caralluma socotrana N. Br, Cephalocroton socotranus Balf.f, Croton socotranus Balf. fil.., Dendrosicycos socotrana Balf.f., Dorstenia gigas Schweinf. ex Balf. fil., Eureiandra balfourii Cogn. & Balf. fil., Kalanchoe farinaceae Balf.f, Limonium sokotranum (Vierh) Radcl. Sm), Oldenlandia pulvinata, Pulicaria diversifolia (Balf. and Pulicaria stephanocarpa Balf. were screened for their acetylcholinesterase inhibitory activity by using in vitro Ellman method at 50 and 200 µg/ml concentrations. Chloroform extracts of Croton socotranus, Boswellia socotrana, Dorstenia gigas, and Pulicaria stephanocarpa as well as methanol extracts of Eureiandra balfourii exhibited inhibitory activities higher than 50 % at concentration of 200 µg. At a concentrations of 50 µg, the chloroform extract of Croton socotranus exhibited an inhibition of 40.6 %.

Sage-called plant species sold in Turkey and their antioxidant activities

Sage is commonly consumed as a herbal tea in Anatolia, where not only Salvia species, but also Sideritis species are called "sage" by the local people. Therefore, it was decided to investigate the most common species of sage-called plants sold in aktars. Eighty-seven samples randomly purchased from 21 provinces throughout Turkey were identified, which finally led to the identification of 7 species; Salvia tomentosa, Salvia fruticosa, Sideritis congesta, Sideritis pisidica var. termessi, Sideritis arguta, Sideritis perfoliata and Sideritis libanotica subsp. linearis. Infusions prepared from all samples were preliminarily tested for their antioxidant activity and 7 representative species were further evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, ferrous ion-chelating and ferric-reducing antioxidant power (FRAP) tests at 0.25, 0.50, and 1.0 mg ml-1 and for their antiacetylcholinesterase activity. The infusions were subjected to the DPPH bioautographic revelatory test, which led to the conclusion that a flavonoid derivative seemed to be responsible for the antioxidant activity in Sideritis congesta and S. pisidica var. termessi.

Development of semagacestat (LY450139), a functional gamma-secretase inhibitor, for the treatment of Alzheimer's disease

BACKGROUND

Alzheimer's disease is thought to be caused by increased formations of neurotoxic amyloid beta (A beta) peptides, which give rise to the hallmark amyloid plaques. Therefore, pharmacological agents that reduce A beta formation may be of therapeutic benefit.

OBJECTIVE

This paper reviews the pharmacology and chemical efficacy of an A beta-lowering agent, semagacestat (LY450139).

METHODS

A review of the published literature pertaining to semagacestat was obtained using several electronic search engines; unpublished data on file at Eli Lilly and Co. were used as supplementary material.

RESULTS/CONCLUSIONS

Semagacestat treatment lowers plasma, cerebrospinal fluid and brain A beta in a dose-dependent manner in animals and plasma and cerebrospinal fluid A beta in humans, compared with placebo-treated patients. On the basis of extant data, semagacestat seems to be well tolerated, with most adverse events related to its actions on inhibition of peripheral Notch cleavage. Thus far, clinical efficacy has not been detectable because of the short duration of the current trials. Phase III trials with 21 months of active treatment are currently underway.

Electroencephalographic effects of galantamine in major depressive disorder

Nicotinic acetylcholine receptor stimulation is a potential target for controlling symptoms in several psychiatric disorders. Galantamine is a cholinesterase inhibitor that can modulate the nicotinic receptor sites. In this study, we examined the effect of galantamine on the quantitative EEG in patients with major depression. Twenty patients were included in a randomized, double-blinded, placebo-controlled trial. Patients received galantamine (8 mg/day for 4 weeks then 16 mg/day for another 4 weeks) or placebo for eight weeks. Quantitative EEG using the international 10 to 20 configuration, 9 minutes of resting, eyes closed, and eyes open was done before and after the study period. Nineteen patients completed the study and their data were included in the final analysis. The results showed that galantamine compared with placebo reduced absolute band power that was statistically significant (using multivariate analysis of variance) for beta wave [F(1,17) = 2.48, P = 0.03]; the between-subject effect was significant on the left and right posterior, and left central regions. The multivariate analysis of variance model for alpha was not significant [F(1,17) = 1.07, P = 0.43]. We suggest that the reduction in absolute power after galantamine administration could be a sign of brain activation as a result of modulation of neurotransmitter release. We recommend the initiation of a larger study to confirm our findings and help in understanding the neuropathology of major depression.

Errorless practice as a possible adjuvant to donepezil in Alzheimer's disease

Six individuals with probable Alzheimer's disease (AD) participated in a phase 1 study employing a repeated measures, parallel baseline design testing the hypothesis that error-free experience during word production practice combined with an acetyl cholinesterase inhibitor would improve confrontation naming ability. While acetyl cholinesterase inhibitors are safe and delay cognition decline associated with AD, improvement over baseline cognition is less evident; clinically significant cognitive deficits persist and progress. Both animal and clinical research strongly implicate acetylcholine in learning, a form of neuroplasticity. In clinical practice, however, people with AD are given cholinergic medications without concomitant systematic/targeted retraining. In this study six participants with probable AD and taking donepezil participated in targeted word production practice using an errorless learning strategy. Results showed that combining behavioral enrichment training and an acetyl cholinesterase inhibitor resulted in significant improvements in verbal confrontation naming of trained items for three of six participants. Differences in baseline dementia severity, living conditions, and medications may have influenced the training response. Detection of substantial treatment effects in 50% of subjects suggests further language treatment studies in AD in combination with an acetyl cholinesterase inhibitor are warranted and provide useful information on inclusion/exclusion criteria for use in subsequent studies.

Cholinergic treatments with emphasis on m1 muscarinic agonists as potential disease-modifying agents for Alzheimer's disease

The only prescribed drugs for treatment of Alzheimer's disease (AD) are acetylcholinesterase inhibitors (e.g., donepezil, rivastigmine, galantamine, and tacrine) and memantine, an NMDA antagonist. These drugs ameliorate mainly the symptoms of AD, such as cognitive impairments, rather than halting or preventing the causal neuropathology. There is currently no cure for AD and there is no way to stop its progression, yet there are numerous therapeutic approaches directed against various pathological hallmarks of AD that are extensively being pursued. In this context, the three major hallmark characteristics of AD (i.e., the CNS cholinergic hypofunction, formation of beta-amyloid plaques, and tangles containing hyperphosphorylated tau proteins) are apparently linked. Such linkages may have therapeutic implications, and this review is an attempt to analyze these versus the advantages and drawbacks of some cholinergic compounds, such as acetylcholinesterase inhibitors, M1 muscarinic agonists, M2 antagonists, and nicotinic agonists. Among the reviewed treatments, M1 selective agonists emerge, in particular, as potential disease modifiers.

Choline pivaloyl ester strengthened the benefit effects of Tacrine and Galantamine on electroencephalographic and cognitive performances in nucleus basalis magnocellularis-lesioned and aged rats

The aim of the present work was the assessment of the effects produced on the electroencephalographic (EEG) activity and the cognitive and memory performances of nucleus basalis magnocellularis (NBM)-lesioned or aged rats by the combined treatment with [2-(2,2-dimethylpropionyloxy)ethyl]trimethylammonium 2,2-dimethylpropionate (choline pivaloyl ester) (CPE) and the Cholinesterase inhibitors (ChEIs) Tacrine (THA) and Galantamine (GAL). Intraperitoneal administration of CPE combined with THA or GAL to both NBM-lesioned or aged rats, produced EEG desynchronisation, and a significant decrease in the energy of the total EEG spectrum and the lower frequency bands (delta 0.25-3 and theta 4-7 Hz) lasting many minutes. Furthermore, drug associations reversed in aged rats the scopolamine (0.2 mg/kg, i.p.)-induced increase in EEG power, slow waves and high-voltage spindle (HVS). Furthermore, the combined administration of CPE and Cholinesterase inhibitors in both NBM-lesioned or aged animals, improved performances in all behavioural tasks, enhancing object discrimination, increasing locomotory activity and alternation choice in T-maze, ameliorating retention in passive avoidance and decreasing escape latency in Morris water maze. In all test, AChEIs and CPE combinations proved to be more effective than CPE, THA or GAL given alone. In conclusion, the present work shows the ability of choline pivaloyl ester in strengthening the positive cerebral activity of THA and GAL.