Intermolecular forces between acetylcholine and acetylcholinesterases studied with atomic force microscopy

With the aid of atomic force microscopy, the intermolecular forces between acetyleholinesterases (AChE) and its natural substrate acetylcholine (ACh) have been studied. Through force spectrum measurement based on imaging of AChE molecules it was found that the attraction force between individual molecule pairs of ACh and AChE was (10±1) pN just before the quaternary ammonium head of ACh got into contact with the negative end of AChE and the decaying distance of attraction was (4±1) nm from the surface of ACHE. The adhesion force between individual ACh and AChE molecule pairs was (25±2) pN, which had a decaying feature of fast-slow-fast (FSF). The attraction forces between AChE and choline (Ch), the quaternary ammonium moiety and hydrolysate of ACh molecule, were similar to those between AChE and ACh. The adhesion forces between AChE and Ch were (20±2) pN, a little weaker than that between ACh and ACHE. These results indicated that AChE had a steering role for the diffusion of ACh toward it and had

Use of donepezil for neurocognitive recovery after brain injury in adult and pediatric populations:a scoping review

There are few pharmacologic options for the treatment of cognitive deficits associated with traumatic brain injury in pediatric patients.Acetylcholinesterase inhibitors such as donepezil have been evaluated in adult patients after traumatic brain injury,but relatively less is known about the effect in pediatric populations.The goal of this review is to identify knowledge gaps in the efficacy and safety of acetylcholinesterase inhibito rs as a potential a djuvant treatment fo r neurocognitive decline in pediatric patients with traumatic brain injury.Investigators queried PubMed to identify literature published from database inception thro ugh June 2023 desc ribing the use of donepezil in young adult traumatic brain injury and pediatric patients with predefined conditions.Based on preselected search criteria,340 unique papers we re selected for title and abstra ct screening.Thirty-two reco rds were reviewed in full after eliminating preclinical studies and pape rs outside the scope of the project.In adult traumatic brain injury,we review results from 14 papers detailing 227 subjects where evidence suggests donepezil is well tole rated and shows both objective and patient-reported efficacy for reducing cognitive impairment.In children,3 pape rs report on 5 children recovering from traumatic brain injury,showing limited efficacy.An additional 15 pediatric studies conducted in populations at risk for cognitive dysfunction provide a broader look at safety and efficacy in 210 patients in the pediatric age group.Given its promise for efficacy in adults with traumatic brain injury and tole rability in pediatric patients,we believe further study of donepezil for children and adolescents with traumatic brain injury is warranted.

Identification of Secondary Metabolites in Tunisian Tilia platyphyllos Scop.Using MALDI-TOF and GC-MS

This study is the first to evaluate the phytochemical content and biological properties of Tunisian T.platyphyllos Scop.A total of 23 compounds of essential oils were identified by gas chromatography-mass spectrometry(GC-MS)analysis of bracts and fruit extracts.The results show that oxygenated monoterpenes were the dominant class of essential oils.The phenolic composition was investigated by matrix-assisted laser desorption/ionizationtime of flight(MALDI-TOF).The analysis showed that the chemical profiles of the ethanolic extracts of bracts and fruits are substantially similar.The highest polyphenol content was found in the ethanolic extracts of the fruits(7.65 mg gallic acid equivalents(GAE).g−1 on dry weight(DW).As for the antioxidant capacity,it was recorded in the essential oils of the fruits(IC_(50)=0.91 mg.mL^(−1)).The results obtained showed that the antioxidant activity of the fruit essential oil was higher than that of the ethanol extract.The fruit essential oil was also found to have the highest reducing power(IC_(50)=0.67 mg.mL^(−1)).In terms of iron-chelating power,fruit essential oil has the highest chelating power(IC_(50)=2.03 mg.mL^(−1)).Compared to the ethanolic extract,the essential oil had the maximum antioxidant capacity.The enzymatic activity of acetylcholinesterase(AChE)inhibition of the essential oil from T.platyphyllos bracts had the most potent inhibitory effect(IC_(50)=0.77 mg.mL^(−1)),followed by the essential oil from the fruits(IC_(50)=0.95 mg.mL^(−1)).The results suggest that T.platyphyllos can be used as a potential source of naturally occurring bioactive compounds and antioxidants.

Emerging significance of butyrylcholinesterase

Butyrylcholinesterase(BChE;EC 3.1.1.8),an enzyme structurally related to acetylcholinesterase,is widely distributed in the human body.It plays a role in the detoxification of chemicals such as succinylcholine,a muscle relaxant used in anesthetic practice.BChE is well-known due to variant forms of the enzyme with little or no hydrolytic activity which exist in some endogamous communities and result in prolonged apnea following the administration of succinylcholine.Its other functions include the ability to hydrolyze acetylcholine,the cholinergic neurotransmitter in the brain,when its primary hydrolytic enzyme,acetylcholinesterase,is absent.To assess its potential roles,BChE was studied in relation to insulin resistance,type 2 diabetes mellitus,cognition,hepatic disorders,cardiovascular and cerebrovascular diseases,and inflammatory conditions.Individuals who lack the enzyme activity of BChE are otherwise healthy,until they are given drugs hydrolyzed by this enzyme.Therefore,BChE is a candidate for the study of loss-of-function mutations in humans.Studying individuals with variant forms of BChE can provide insights into whether they are protected against metabolic diseases.The potential utility of the enzyme as a biomarker for Alzheimer’s disease and the response to its drug treatment can also be assessed.

Cholinesterase Activity as an Indicator of Health Risks among Kou Valley Farmers

Introduction: Pesticides are currently an essential component of agricultural production techniques for controlling pests and weeds. In Burkina Faso, non-compliance with good practice in the use of pesticides poses a real health problem for the population. This study examines the health risks associated with pesticide management in rice-growing areas. Material and Methods: A field survey was conducted in Bama, involving farmers, focusing on their socio-demographic characteristics, pesticide usage, and health effects. Cholinesterase levels were measured in subsample of farmers using a portable device. Data were analysed using Microsoft Excel, calculating means and percentages for various practices. Health consultations, protection methods, and pesticide management were studied. Erythrocyte acetylcholinesterase activity was compared before and after treatment. Data were categorised into classes based on inhibition levels, and correlation analyses determined relationships between variables such as age, years of experience, and cholinesterase activity. Results: The results indicate that rice cultivation is mainly carried out by a fairly young population, with nearly 63% being under the age of 50. Common poor practices in pesticide use include improper storage and reuse of leftover pesticides. Seven types of pesticides were identified, including organophosphates such as glyphosate, which was used in 26.7% of cases. This organophosphate has resulted in class B poisoning, causing a 30% - 50% reduction in erythrocyte cholinesterase activity. The health effects of pesticide use are felt by agricultural farmers through various symptoms of poisoning. Conclusion: To reduce the occurrence of pesticide poisoning, it is essential to launch information and awareness campaigns among the population and farmers to promote safe practices in pesticide use in Bama, Burkina Faso.

Lactoferrin modification of berberine nanoliposomes enhances the neuroprotective effects in a mouse model of Alzheimer’s disease

Previous studies have shown that berberine has neuroprotective effects against Alzheimer’s disease,including antagonizing tau phosphorylation,and inhibiting acetylcholinesterase activity and neural cell apoptosis.However,its low bioavailability and adverse reactions with conventional administration limit its clinical application.In this study,we prepared berberine nanoliposomes using liposomes characterized by low toxicity,high entrapment efficiency,and biodegradability,and modified them with lactoferrin.Lactoferrin-modified berberine nanoliposomes had uniform particle size and high entrapment efficiency.We used the lactoferrin-modified berberine nanoliposomes to treat a mouse model of Alzheimer’s disease established by injection of amyloid-beta 1-42 into the lateral ventricle.Lactoferrin-modified berberine nanoliposomes inhibited acetylcholinesterase activity and apoptosis in the hippocampus,reduced tau over-phosphorylation in the cerebral cortex,and improved mouse behavior.These findings suggest that modification with lactoferrin can enhance the neuroprotective effects of berberine nanoliposomes in Alzheimer’s disease.

New Neuraminidase Inhibitory Alkaloids from the Mangrove Soil-Derived Fungus Arthrinium sp.SCSIO 41305

New alkaloid,(E)-2-(hydroxyimino)-4-methylpentanamide(1)and a new cyclopentano[b]pyridine,4-hydroxy-7-methyl-6,7-dihydro-5H-cyclopenta[c]pyridin-5-one(2),together with ten known compounds(3–12)were isolated from the mangrove soil-derived fungus Arthrinium sp.SCSIO 41305.Extensive spectroscopic analysis and X-Ray crystallographic analysis were used to elucidate the structure of(E)-2-(hydroxyimino)-4-methylpentanamide(1),including its absolute configuration.All the isolated compounds(1–12)were evaluated for their antimicrobial and enzyme inhibitory activities against acetylcholinesterase(ACh E),neuraminidase(NAs),and phosphatidylinositol 3-kinase(PI3K).Among them,compounds 1 and 3 exhibited strong neuraminidase inhibitory activity with IC_(50)values of 12.04,1.92μmol L^(-1)(IC_(50)20μmol L^(-1)for oseltamivir acid),while compounds 5,6,8,and 10showed moderate neuraminidase inhibitory activity,and compounds 6–10 displayed weak enzyme inhibitory activities against PI3K.

Effect of Purified Paper Wasp Ropalidia marginata Venom Toxin Enzyme Activity in Blood Serum, Liver, and Gastrocnemius Muscle of Albino Mice

In the present, investigation effects of sub-lethal dose of purified paper wasp Ropalidia marginata venom toxins were evaluated on important metabolic enzymes i.e. ALP ACP, GPT, GOT, LDH, and AchE enzyme activity in serum, liver, and gastrocnemius muscles of albino mice. Alkaline phosphatase was found to be increased up to 119.9% at the 6th hr of the toxin injection in comparison to control. This elevation may be due to cytolysis. Maximum increase i.e., 153.33% level of glutamate pyruvate transaminase (GPT) was found at 6 hrs of 40% of 24-h LD50 treatment while it was found to be 151.1% at 6 hrs of 24 hr 80% of LD50, venom injection. A significant elevation was observed in LDH activity in serum, liver, and muscles, while the activity of AchE was decreased in serum, liver, and gastrocnemius muscles of albino mice after injecting the sub-lethal dose of Ropalidia marginata venom. This increase in the activity of LDH produces liver damage, massive disintegration and necrosis of hepatic cells. This elevation in LDH level led to a significant increase in the glucose catabolism and elevated oxidative stress in muscle and liver cells. It also displays insufficient oxygen supply and consequently leads to cell death. In experimental animals, venom toxin treatment decreased AchE level, and animals showed muscular paralysis. When mice were treated with 40% and 80% of 24-h LD50 of purified venom caused a significant (p < 0.05) elevation in the level of ACP, GOT, GPT, and LDH while the reduction in ALP and AChE level. Present study will be useful in the development of prototypes for study of pharmacological and therapeutic effects of various venom toxins. For this purpose structure activity relationship of enzyme and venom toxin, its due interaction to various metabolic enzymes and receptors must be explored.

Effects of Purified Indian Cattle Tick Rhipicephalus microplus Saliva Toxins on Various Enzymes in Blood Serum, Liver and Muscles of Albino Mice

In the present investigation, in vivo effects of purified ticks’ saliva toxin were evaluated on the level of certain important cellular metabolic enzymes i.e. acid phosphatase (ACP), alkaline phosphatase (ALP), glutamate pyruvate transaminase, glutamate oxaloacetate transaminase and lactic dehydrogenase. For this purpose, sub-lethal doses, 40% and 80% of 24 h LD50 purified saliva toxins of Rhipicephalus microplus (Canestrini, 1888) were injected subcutaneously in the albino mice. In treated mice saliva toxins targeted membrane-bound enzymes i.e. serum acid phosphatase and alkaline phosphatase, its level was increased from 118.30% to 163.63% at the 6th hr in comparison to the control. Besides this, the levels of serum glutamate pyruvate transaminase (GPT) and glutamate oxaloacetate transaminase (GOT) and lactic dehydrogenase (LDH) also increased up to 161.11% (at 6th hr), 148.27 (at 8th hr) and 125.45% (at 6th hr) respectively in comparison to control. An increase in the level of LDH showed insufficient oxygen supply, massive disintegration of cells and leakage of the enzyme into the circulation. It clearly indicated the toxic effects of saliva toxins on the membrane of blood cells, hepatocytes and myocardial muscle cell functions in albino mice. On the other hand activity of acetyl cholinesterase was reduced by 65.51% at the 6th hr of the saliva toxin injection in comparison to the control. This inhibition of acetyl cholinesterase activity caused the accumulation of acetylcholine molecules at the synaptic junctions and led to prolonged activation of acetylcholine receptors. It caused permanent stimulation of nerves and muscle cells that may result in muscular paralysis and finally death of the animal.

Computational interaction analysis of organophosphorus pesticides with different metabolic proteins in humans

Pesticides have the potential to leave harmful effects on humans, animals, other living organisms, and the environment. Several human metabolic proteins inhibited after exposure to organophosphorus pesticides absorbed through the skin, inhalation, eyes and oral mucosa, are most important targets for this interaction study. The crystal structure of five different proteins, PDBIDs： 3LII, 3NXU, 4GTU, 2XJ1 and 1YXA in Homo sapiens （H. sapiens）, interact with organophosphorus pesticides at the molecular level. The 3-D structures were found to be of good quality and validated through PROCHECK, ERRAT and ProSA servers. The results show that the binding energy is maximum -45.21 relative units of cytochrome P450 protein with phosmet pesticide. In terms of H-bonding, methyl parathion and parathion with acetylcholinesterase protein, parathion, methylparathion and phosmet with protein kinase C show the highest interaction. We conclude that these organophosphorus pesticides are more toxic and inhibit enzymatic activity by interrupting the metabolic pathways in H. sapiens.

Fe^(3+)对泥鳅脑组织AChE活性的影响

以泥鳅(Misgurnus anguillicaudatus)为材料,比较了脑、肠、肝脏和胰脏的乙酰胆碱酯酶(Acetylcholin esterase,AChE)活性,然后采用体内染毒的方法,研究Fe3+对脑组织AChE活性的影响。结果表明,1%组织匀浆液中,脑、肠、肝脏、胰脏组织中AChE活性分别是1.42、0.35、0.06、0.15 U/mg;14 d后,与对照组相比,在60 mg/L Fe3+溶液中,泥鳅脑组织中AChE活性显著降低(P<0.05),表明Fe3+对泥鳅具有神经毒性。

混配农药中毒防治研究

首次在我国开展大规模的混配农药中毒流行病学调查,发现接触混配农药是当前发生农药中毒的重要危险因素,为针对性的预防提供了科学依据。毒理学研究证实多数农药混剂呈增毒效应或协同作用,且与其毒代动力学变化有密切关系,为今后开发高效、低毒的混配农药提供了毒理学依据。在国内外首次建立甲基对硫磷单克隆抗体酶联免疫测定法,并成功研制便携式血胆碱酯酶快速测定仪;这些检测接触、效应生物标志物的灵敏、特异、便捷的方法已试用于现场,并具有开发为产品的前景。同时还发现对氧磷酶基因在192位点的单核苷酸多态性,可能是甲基对硫磷免疫毒性作用的易感性生物标志物之一。在总结不同类别农药混配后所致中毒的临床表现特点和规律的基础上,修订现行的农药中毒诊断标准,增添了有机磷单剂及混剂中毒所致“中间期肌无力综合征”的新内容,将提高我国农药中毒的诊治水平。本研究主要成果达国内领先和国际先进水平。

星豹蛛乙酰胆碱酯酶(AChE)活性测定及药剂对其活性的抑制作用(英文)

[ Objective ] The paper was to systemically study the characteristics of acetyl cholinesterase （ACHE） in Pardosa astrigera, and confirm the occurrence and development of its pesticide resistance and the resistance level, thereby establishing a quick and accurate detection method for enzyme activity. [ Method] The optimal conditions for assaying the activity of AChE in different parts of P. astrigera were determined by orthogonal experiment. The distribution conditions of acetyl cholinesterase （AChE） in different tissues of P. astrigera were further studied, and the sensitivities of the enzyme tO four common pesticides were also determined. [ Result] The optimal condition for assaying the activity of AChE in cephalothorax, abdomen and appendage of P. astrigera was as follows, enzyme concentrations： 12, 18 and 29 g/L; substrate concentrations： 0.6, 1.0 and 1.0 mmol/L; pH value, 7.0; reaction temperatures： 30, 35, 35℃ ; reaction time, 5 rain. AChE was mainly distributed in the cephalothorax of P. astrigera. The specific activity of AChE in the extract solution with Triton X-100 was higher than that in the solution without Triton X-100. The median inhibitory concentrations （IC50） of methomyl, phoxim, betacypermethrin, chlorpyrifos against AChE in the cephalothorax of P. astrigera were 7.76 × 10^-5, 1.76×10^-4, 4.12 ×10^-4 and 4.94 ×10^-4 mol/L, respectively. [ Conclusion] AChEs in P. astrigera were membrane-bounded. The inhibition of four pesticides against AChE in the cephalothorax of P. astrigera had good dese-effect, this indicated that AChE in the cephalothorax of P. astrig- era could be used as the biochemical marker to monitor the contamination of organic phosphorus, carbamate and pyrethroid pesticides in the environment.

Influences of Cu or Cd on the neurotoxicity induced by petroleum hydrocarbons in ragworm Perinereis aibuhitensis

The ecotoxicological effects of heavy metals and petroleum hydrocarbons （PHCs） on ragworms are still vague. The relationships between toxicological indices （mortality and acetylcholinesterase （ACHE） activity） and concentrations of toxicants （Cu, Cd, and PHCs） were examined in the estuary keystone species Perinereis aibuhitensis in laboratory conditions. The results of single toxicant indicated that three toxicants had potentially physiological toxicity to P. aibuhitensis. The estimated 4-d and 10-d LC50 for Cu, Cd, and PHCs was derived from the relationships between mortality and toxicants concentrations. Notable changes in the morphological signs and symptoms of P. aibuhitensis exposed to PHCs were observed. The ACHE activity of P. aibuhitensis was more sensitive to the toxicity of PHCs than the others. The results of combined toxicants implied that the combined toxicity of Cu or Cd and PHCs to P. aibuhitensis was related to the concentration combination of toxicants. Compared to single PHCs treatment, the addition of Cu or Cd significantly mitigated the neurotoxicity of PHCs to ACHE activity in P. aibuhitensis, which showed an antagonistic effect.

Oxidative Stress and Free Radical Damage in Patients With Acute Dipterex Poisoning

Objective To investigate whether acute dipterex poisoning (ADP) may cause oxidative stress and free radical damage in the bodies of acute dipterex poisoning patients (ADPPs), and to explore the mechanisms by which ADP may cause oxidative stress and free radical damage. Methods Fifty ADPPs and fifty healthy adult volunteers (HAVs) whose ages, gender and others were matched with the ADPPs were enrolled in a randomized controlled study, in which concentrations of nitric oxide (NO), vitamin C (VC), vitamin E (VE) and P-carotene (P-CAR) in plasma as well as concentration of lipoperoxide (LPO), and activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and acetylcholinesterase (AChE) in erythrocytes were determined by spectrophotometric analytical methods. Results Compared with the average values of experimental parameters in the HAVs group, the average values of plasma NO and erythrocyte LPO in the ADPPs group were significantly increased (P<0.0001), while those of plasma VC, VE and P-CAR as well as erythrocyte SOD, CAT, GPX and AChE in the ADPPs group were significantly decreased (P<0.0001). Bivariate correlation analysis and partial correlation analysis suggested that when NO and LPO values were increased, and VC, VE, β-CAR, SOD, CAT and GPX values were decreased in the ADPPs, AChE value was decreased gradually in the ADPPs (P<0.001-0.0001). Reliability analysis of experimental parameters reflecting oxidative stress and free radical damage in the ADPPs showed that the reliability coefficient (8 items) alpha=0.6909, and the standardized item alpha=0.8574. Conclusion The findings in the present study suggest that ADP can cause oxidative stress and free radical damage, and inhibit markedly erythrocyte acetylcholinesterase activity in ADPPs.

In vitro screening for acetylcholinesterase inhibition and antioxidant activity of medicinal plants from southern Africa

Objective:To determine the acetylcholinesterase inhibitory（AChE1） and antioxidant activity of the ethyl acetate and methanol extracts of 12 traditional medicinal plants used in the treatment of neurological disorders.Methods:AChEI activity was determined spectrophotometrically using the Ellman’s colorimetric method.Antioxidant activity was carried out by determining the ability of the extracts to scavenge 2,2-diphenyl-1-picryl hydrazyl（DPPH） and 2,2’-azinobis- 3-ethylbenzothiazoline-6-sulfonic acid（ABTS） radicals.The levels of total phenols,flavonoids and flavonols were determined quantitatively using spectrophotometric methods.Results:AChEI was observed to be dose-dependent.Lannea schweinfurthii（L.schweinfurthii）（Engl.） Engl.and Scadoxus puniceus（S.puniceus）（L.） Friis & I.Nordal.root extracts showed the lowest IC50 value of 0.000 3 mg/mL for the ethyl acetate extracts while Zanthoxylum davyi（Z.davyi）（I.Verd.） P.G. Watermann had the lowest IC50 value of 0.01 mg/mL for the methanol extracts in the AChEI assay. The roots of Piper capense（P.capense） L.f.,L.schweinfurthii,Ziziphus mucronata（Z.mucronata） Willd.,Z.davyi and Crinum bulbispermum（C.bulbispermum）（Burm.f.） Milne-Redh.& Schweick.showed noteworthy radical scavenging activity and good AChEI activity.Conclusions: Five plants show good antioxidant and AChEI activity.These findings support the traditional use of the plants for treating neurological disorders especially where a cholinesterase mechanism and reactive oxygen species（ROS） are involved.

Therapeutic potential of Gastrodia elata Blume for the treatment of Alzheimer's disease

Several studies have demonstrated that the Chinese herb Gastrodia elata Blume can protect against amyloid beta-peptide （Ap）-induced cell death. To investigate the possible therapeutic effects of Gastrodia elata Blume on Alzheimer＇s disease, we established a rat model of AIzheimer＇s disease by injecting A325-35 into bilateral hippocampi. These rats were intragastrically administered 500 or 1 000 mg/kg Gastrodia elata Blume per day for 52 consecutive days. Morris water maze tests showed that Gastrodia elata Blume treatment significantly improved the spatial memory of Alzheimer＇s disease rats. Congo red staining revealed that Gastrodia elata Blume significantly reduced the number of amyloid deposits in the hippocampus of these rats. Western blot analysis showed that choline acetyltransferase expression in the medial septum and hippocampus was significantly increased by the treatment of Gastrodia elata Blume, while EIIman method showed significant decrease in the activity of acetylcholinesterase in all three regions （prefrontal cortex, medial septum and hippocampus）. These findings suggest that long-term administration of Gastrodia elata Blume has therapeutic potential for Alzheimer＇s disease.

Multitarget therapeutic strategies for Alzheimer's disease

Neurodegenerative diseases such as Alzheimer's, Huntington's and Parkinson's diseases have multifaceted nature because of the different factors contributing to their progression. The complex nature of neurodegenerative diseases has developed a pressing need to design multitarget-directed ligands to address the complementary pathways involved in these diseases. The major enzyme targets for development of therapeutics for Alzheimer's disease are cholinesterase and β-secretase enzymes. In this review, we discuss recent advances in profiling single target inhibitors based on these enzymes to multitarget-directed ligands as potential therapeutics for this devastating disease. In addition, therapeutics based on iron chelation strategy are discussed as well.

Study of enzyme biosensor based on carbon nanotubes modified electrode for detection of pesticides residue

The paper describes a controllable layer-by-layer （LBL） self-assembly modification technique of multi-walled carbon nanotubes （MWNTs） and poly（diallyldimethylammonium chloride） （PDDA） towards glassy carbon electrode （GCE）, Acetylcholinesterase （ACHE） was immobilized directly to the modified GCE by LBL self-assembly method, the activity value of AChE was detected by using i-t technique based on the modified Ellman method. Then the composition of carbaryl were detected by the enzyme electrode with 0.01U activity value and the detection limit of carbaryl is 10^- 12 g L ^-1 so the enzyme biosensor showed good properties for pesticides residue detection.