Acetylcholinesterase Activity Research Articles

Behavioral and Biochemical Effects of an Arylhydrazone Derivative of 5-Methoxyindole-2-Carboxylic Acid in a Scopolamine-Induced Model of Alzheimer’s Type Dementia in Rats

Alzheimer’s disease (AD) has long proven to be a complex neurodegenerative disorder, with cholinergic dysfunction, oxidative stress, and neuroinflammation being just a few of its pathological features. The complexity of the disease requires a multitargeted treatment covering its many aspects. In the present investigation, an arylhydrazone derivative of 5-methoxyindole-2-carboxylic acid (5MeO), with in vitro strong antioxidant, neuroprotective and monoamine oxidase B-inhibiting effects, was studied in a scopolamine-induced Alzheimer-type dementia in rats. Using behavioral and biochemical methods, we evaluated the effects of 5MeO on learning and memory, and elucidated the mechanisms of these effects. Our experiments demonstrated that 5MeO had a beneficial effect on different types of memory as assessed by the step-through and the Barnes maze tasks. It efficiently restored the decreased by scopolamine brain-derived neurotrophic factor and acetylcholine levels and normalized the increased by scopolamine acetylcholine esterase activity in hippocampus. Most effective 5MeO was in counteracting the induced by scopolamine oxidative stress by decreasing the increased by scopolamine levels of lipid peroxidation and by increasing the reduced by scopolamine catalase activity. Blood biochemical analyses demonstrated a favorable safety profile of 5MeO, prompting further pharmacological studies suggesting 5MeO as a safe and efficient candidate in a multitargeted treatment of AD.

Toxicity comparison of polylactic acid and polyethylene microplastics co-exposed with methylmercury on Daphnia magna

The prevalence of microplastics (MPs) in aquatic ecosystems has become a significant environmental concern due to their persistence and potential toxicity. Although bioplastics, such as polylactic acid (PLA), are promoted as eco-friendly alternatives to conventional plastics, their toxicity remains poorly understood. This study compares the toxicity and pollutant vector roles of polar PLA-derived bio-microplastics (bio-MPs) with apolar low-density polyethylene (LDPE) MPs, both individually and in combination with methylmercury (MeHg), in Daphnia magna. PLA bio-MPs, both alone and in combination with MeHg, significantly reduced survival rates and reproduction while inducing oxidative stress. Additionally, PLA bio-MPs increased Hg accumulation and negatively impacted acetylcholinesterase activity and vitellogenin gene expression compared to LDPE MPs. The findings of this study suggest that PLA bio-MPs, despite being in vivo biodegradable, may pose similar or even greater environmental risks than fossil fuel-based MPs, particularly due to their potential to enhance the bioaccumulation and toxicity of coexisting pollutants.

Engineered Biocorona on microplastics as a toxicity mitigation strategy in marine environment: Experiments with a marine crustacean Artemia salina

The marine environment has become a major sink for microplastics (MPs) wastes. When MPs interact with biological macromolecules, the biocorona forms on their surface, which can alter their biological reactivity and toxicity. In this study, we investigated the impact of biocorona formation on the toxicity of aminated (NH2) and carboxylated (COOH) polystyrene MPs towards the marine crustacean Artemia salina. Biocoronated MPs were prepared using cell-free extracts (CFEs) from microalgae Chlorella sp. (phytoplankton) and the brine shrimp Artemia salina (zooplankton). The results revealed that biocorona formation effectively reduced the toxicity of MPs. Pristine NH2-MPs exhibited higher reactive oxygen species production (ROS) (182%) compared to COOH-MPs (162%) in Artemia salina. Notably, NH2-MPs coronated with brine shrimp CFE exhibited a substantial reduction in ROS production (127%) than those coronated with algal CFE, with COOH-MPs showing a similar trend (120%). Biocorona formation also significantly decreased malondialdehyde (MDA) levels and antioxidant activity compared to pristine MPs. Molecular docking and dynamics simulations demonstrated a strong binding between polystyrene and acetylcholinesterase (AChE). In vitro studies indicated that pristine NH2-MPs exhibited more reduction in AChE activity (84%) compared to COOH-MPs (95%). However, no significant reduction in AChE activity was observed upon exposure to MPs coronated with either algal or brine shrimp cell-free extracts. Independent action modeling indicated an antagonistic interaction for MPs coronated with both the CFEs. Pearson correlation and cluster heatmap analysis suggested that the toxicity reduction in Artemia salina might be driven by decreased oxidative stress followed by the corona formation. Overall, this study provides valuable insights into the potential of biomolecules from phytoplankton and zooplankton to reduce MPs toxicity in Artemia salina, while highlighting their role in modulating the toxicity of other marine pollutants.

Construction of a N-CDs/AuNCs@ZIF-8-assisted ratiometric fluorescent nanosensor for glyphosate detection in edible and medicinal malt

Glyphosate (Gly) is a widely-used herbicide in food production, while, the residue of which due to the long-term and excessive overspray poses serious threats to public health. The development of reliable methods for its sensitive detection is of great urgency. In this study, a novel ratiometric fluorescent nanosensor by encapsulating N-doped carbon dots (N-CDs) and gold nanoclusters (AuNCs) in zeolitic imidazole framework-8 (ZIF-8) as the dual-emissive fluorescence probes at 410 and 650 nm, respectively, was constructed for Gly detection. Due to the adsorption property of ZIF-8, the N-CDs/AuNCs@ZIF-8 nanoprobes accumulated Cu2+ to quench the red fluorescence of AuNCs, and the blue fluorescence of N-CDs was stable. While thiocholine, a product of acetylthiocholine, hydrolyzed by acetylcholinesterase could coordinate with Cu2+, resulting in significant fluorescence recovery of AuNCs. This phenomenon was utilized for the quantitation of Gly, due to its inhibitory effect on acetylcholinesterase activity. By calculating the fluorescence intensity ratio (I650/I410), Gly in real sample could be accurately determined in a concentration range of 2–100 ng/mL with a limit of detection of 1.92 ng/mL because of the anti-interference and the self-correction ability of the two fluorescence signals. The N-CDs/AuNCs@ZIF-8 nanoprobes-assisted ratiometric fluorescent nanosensor exhibited unique merits of rapid construction, simple operation, high specificity, and good accuracy for Gly in edible and medicinal malt samples with recoveries of 93.7–108.2 %. This study presents a multiple tool for the versatile sensing of trace pesticides in more food matrices, which can be extended to a full range of environmental and food safety applications.

Effects of Laurus extract against cadmium-induced neurotoxicity in rats

Cadmium (Cd) is a hazardous heavy metal with widespread environmental presence, posing significant threats to human and animal health. This study investigates the neurotoxic effects of Cd exposure and explores the therapeutic efficacy of Laurus nobilis L. in counteracting these adverse effects. Cd exposure induces oxidative stress and neurotoxicity, leading to neuronal damage and histopathological alterations. Laurus, known for its antioxidant properties, is assessed for its potential in mitigating Cd-induced neurotoxicity through in vitro antioxidant assays, GC–MS analysis, HPLC profiling, and experimental animal models. Results demonstrate that Laurus ethanolic extract exhibits significant antioxidant activity, attributed to its phenolic and flavonoid constituents. GC–MS analysis reveals various bioactive compounds in the extract, including Hexadecanoic acid methyl ester and (Z)-13-Docosenamide, which posses neuroprotective properties. HPLC analysis identifies phenolic compounds such as ellagic acid and flavonoids like rutin and kaempferol in the extract. In vivo studies in rats exposed to Cd demonstrate that Laurus extract administration mitigates Cd-induced alterations in body and brain weight, hematological parameters, liver and kidney function, oxidative stress markers, and acetylcholinesterase (AchE) activity. Histopathological examination confirms the protective effects of Laurus against Cd-induced neuronal damage. The SOD model, validated with high resolution (2.05 Å) and strong R values (work: 0.192, free: 0.236, observed: 0.194), shows strong structural stability (C-score: 0.30). Docking studies reveal high binding affinities of kaempferol (−8.1 kcal/mol) and rutin (−8.7 kcal/mol) with SOD with kaempferol demonstrating superior solubility, lipophilicity, and drug-likenessSimulation analysis confirms the protein’s flexibility and adaptability, highlighting its therapeutic potential, especially with kaempferol. These findings suggest the therapeutic potential of Laurus. as a natural remedy for Cd-induced neurotoxicity, highlighting its antioxidant and neuroprotective properties.

Therapeutic impact of a benzofuran derivative on Aluminium chloride-induced Alzheimer's disease-like neurotoxicity in rats via modulating apoptotic and Insulin 1 genes

Neurodegenerative disorders such as Alzheimer’s disease (AD) are age-related and are fatal in advanced cases. There is a limited efficacy of drugs used for the management of these diseases. Herein, the neurotherapeutic efficacy of a benzofuran-derivative-7 (BF-7) was investigated. Aluminum chloride (AlCl3) was employed to induce AD-like brain toxicity in rats. The rats were divided into four groups: Negative control, AlCl3-induced AD rats (100 mg/kg body weight, orally), AlCl3-AD induced rats treated with BF-7 (10 mg/kg body weight, orally), AlCl3-AD-induced rats treated with the standard drug “Donepezil” (10 mg/kg body weight, orally). The behavioral performance was tested using a beam-balance test. Brain and serum acetylcholinesterase (AChE) activities and the brain levels of norepinephrine, dopamine (DA), and serotonin (5-HT) were measured. The genetic expression of Bcl-2, Bax, caspase-3, and insulin 1 were assayed. The histopathological imaging and the immunohistochemical evaluation of Glial Fibrillary Acidic Protein (GFAP) were investigated in the cerebral cortex. Treatment of AD-rats with BF-7 mitigated AlCl3-induced neurotoxicity by improving motor functions, counteracting apoptosis, and exerting cholinergic functions. In addition, the genetic expression of Insulin 1 was upregulated significantly in AD-induced rats treated with BF-7. This compound could be used as a promising candidate for neurotherapeutic drug discovery against AD or any other toxic brain disorders.

Efficacy of Titanium Dioxide Nanoparticles Using Juniperus phoenicea in Controlling Rice Weevil (Sitophilus oryzae) and Its Effect on the Microbial Contents and Nutritive Value of Grains

The rice weevil, Sitophilus oryzae is a primary pest attack many kinds of crops. It causes a lot of loss and reduces the economic values of products. The study investigated to determine the insecticidal effect of titanium dioxide nanoparticles using Juniperus phoenicea (TiO2 NPs) against the insect, and the nutritional and antimicrobial value of rice grains after treatment by TiO2 NPs was estimated. Adult was the target of bioassay of the biocomponent. Four concentrations were prepared as 30, 50, 80 and 100%. Some biochemical components were evaluated as response indicators of insect. Obtained data demonstrated significant differences between the four concentrations, where the highest mortality was recorded after 120 h. On the adults (85%). Treatment with the titanium dioxide nanoparticles inhibited the activities of acetylcholine esterase and total soluble protein. While it increases the activity of catalase as antioxidant enzyme. Nutritional values increased with increasing the proportion of TiO2 NPs, except for the decrease in protein. No colonization of coliform bacteria and fungi cell was recorded in 80% of TiO2 NPs, aerobic bacteria were reduced to a lower number 12 CFU/g 103 at 100%. Biosynthesized titanium dioxide nanoparticles with J. phoenicea extract is promising bio-insecticide and antimicrobial in integrated pest management control, preserving the nutritional value of grains during storage.

Pharmacological evaluation of rice varieties, Hassawi and Njavara

Hasswai and Njavara are two notable international and Indian red rice cultivars that provide a variety of nutrients and phytochemicals. An effort was made to investigate the pharmacological properties of these rice types. In conclusion, both types of rice exhibit lipid peroxidation, acetylcholinesterase, thrombolytic, anti-arthritic, antioxidant, and anti-inflammatory properties. Methanol extracts showed increased acetylcholinesterase, thrombolytic, and antioxidant activity in the current investigation. On the other hand, aqueous extracts have stronger anti-inflammatory, anti-arthritic, lipid peroxidation, protease inhibition, and amylose inhibitory properties. Of these two varieties, Hasawi showed good activities concerning amylose inhibition, thrombolytic activity, antioxidant activity, and anti-inflammatory and lipid peroxidation. However good protease inhibition and acetylcholinesterase activities were noted in Njavara than in Hasawi. This points to a specific phytochemical composition that these two rice varieties contain. More detailed investigations are warranted to score the exact phytochemical basis for the observed activities.

Developmental toxicity and biochemical and biomarker in the zebrafish (Danio rerio) embryo exposed to biosynthesized cadmium oxide nanoparticles

Cadmium oxide nanoparticles (CdO-NPs) play an important role in health applications due to their antibacterial properties. However, ecotoxicological investigations of these NPs and their adverse effects on aquatic organisms are necessary to protect the environment. Zebrafish is widely used as a model organism to explore toxic effects at multiple levels of integration. Hence, the objective of this work was to pursue possible harmful impacts of CdO -NPs that have been produced through biosynthesis, utilizing extract from the lily plant Gloriosa superba leaves, on the growth and biochemical changes in zebrafish (Danio rerio) embryos and larvae. UV, SEM, TEM, FTIR, EDAX, DLS, and ZETA-potential techniques were employed to examine the structure and morphology of the biosynthesized CdO-NPs. The identification of bioactive chemicals from the leaf extract of G. superba was conducted using GC-MS. To study the in vivo toxicity of CdO-NPs, zebrafish embryos and larvae were treated with two different concentrations of G. superba leave extract (0.5 and 1.0 mg/mL) at 96 hours after fertilization (hpf). Bended tail, pericardial edema, shortened yolk sac extension, scoliosis, and damaged eyes were observed in the CdO-NPs treated groups. In addition, there was a considerable decrease in the levels of superoxide dismutase (SOD), catalase (CAT), glutathione S-transferases (GST), and lipid peroxidation (LPO). The CdO-NPs treated groups showed significant alterations in biochemical markers, including protein levels, glucose levels, and acetylcholinesterase (AChE) activity. Overall, our findings indicated that CdO-NPs induced a dose-dependent toxicity in zebrafish embryos. The investigated parameters serve as reliable biomarkers for the surveillance of CdO-NPs in aquatic ecosystems and their impact on living animals.

Gallic acid attenuates lipopolysaccharide - induced memory deficits, neurochemical changes, and peripheral alterations in purinergic signaling.

Neuroinflammation is associated with many neurological disorders. Gallic acid (GA) has attracted significant attention due to its biological properties, such as neuroprotective, anti-inflammatory, and antioxidant effects. In this study, we evaluated the effects of GA in memory, TNF-α levels, oxidative stress, and activities of acetylcholinesterase (AChE), Na+, K+-ATPase and Ca2+-ATPase in the brain of mice exposed to lipopolysaccharide (LPS). Additionally, we evaluated alterations in adenine nucleotides and nucleosides in the serum. Male mice were orally pretreated with vehicle or GA (50 or 100mg/kg) for 14 days. Between days 8 and 14, the animals also received LPS injection (250µg/kg) or saline. At the end of the experimental protocol, the animals were submitted to object recognition test, euthanized and cerebral cortex, hippocampus, striatum and blood were collected. LPS induced memory deficits, which were prevented by GA treatment. GA protected against LPS-induced oxidative damage in the cerebral cortex, hippocampus and striatum by reducing reactive oxygen species and nitrite levels, while increasing total thiol content and activities of antioxidant enzymes. GA also prevented LPS-induced alterations in AChE, Na+, K+-ATPase, and Ca2+-ATPase activities in brain structures. LPS elevated TNF-α levels in the hippocampus and cerebral cortex, which were attenuated by GA treatment. Furthermore, LPS caused a reduction in ADP and AMP hydrolysis and an increase in adenosine deamination in the serum, which were also prevented by GA. The effects of GA against neuroinflammation may be attributed to its potent antioxidant and anti-inflammatory properties, which modulate various pathways, including those involved in memory mechanisms.

Duguetia furfuracea (A.ST. Hil.) Saff.: Neuroprotective Effect on Chemically Induced Amnesia, Anxiolytic Effects and Preclinical Safety Evaluation in Mice

Duguetia furfuracea, “araticum-seco”, is known to contain several bioactive compounds that can mitigate oxidative stress and act on the central nervous system (CNS). This effect is partly attributed to its potent antioxidant and acetylcholinesterase (AChE) inhibitors. In this study, the effects were explored of the methanolic extract (MEDF) and alkaloid fraction (AFDF) of D. furfuracea (leaves) on cognitive behaviors in male mice with scopolamine (Scop)-induced cognitive impairment and biochemical parameters. Additionally, anxiolytic behavior, subacute toxicity, molecular docking and antioxidant activity were reported. MEDF (30, 100 or 300 mg/kg) or AFDF (30 mg/kg) were orally administered for 16 days and Scop (intraperitoneally, i.p.) between days 11 and 16. The anxiolytic behavior (open field test and marble burying) in healthy mice, and the Scop-induced memory impairment (object recognition test and Morris water maze (MWM)) were assessed, and the biochemical parameters (malondialdehyde (MDA) and AChE levels) were measured after euthanasia. The subacute toxicological impact of MEDF was assessed in female Swiss mice for 28 days. MEDF and AFDF were available for the DPPH, ABTS and β-carotene/linoleic acid models. The results revealed that MEDF and AFDF exhibit anxiolytic effects and significantly alleviated Sco-induced memory impairment, inhibited AChE in the cortex (40%) and MDA (51.51%) levels. Reticuline was reported in AFDF and molecular coupling with AChE involves link-type hydrogen bonds and van der Waals interactions. MEDF exhibited antioxidant capacity (DPPH, IC50 = 18.10 ± 1.70 µg/mL; ABTS, IC50 = 10.41 ± 1.69 µg/mL). MEDF did not reveal signs of toxicity. In conclusion, D. furfuracea shows promise in mitigating scopolamine-induced memory deficits, potentially because it inhibits AChE activity, reduces MDA levels, and enhances antioxidant activities.

Brivaracitam Ameliorates Increased Inflammation, Oxidative Stress, and Acetylcholinesterase Activity in Ischemic Mice

Brivaracitam Ameliorates Increased Inflammation, Oxidative Stress, and Acetylcholinesterase Activity in Ischemic Mice

Erythrosine-Induced Neurotoxicity: Evaluating Enzymatic Dysfunction, Oxidative Damage, DNA Damage, and Histopathological Alterations in Wistar Rats.

Erythrosine, a synthetic red dye widely used in food products, has been linked to potential health risks, raising concerns about its safety. This study aimed to evaluate the subacute toxicity of the synthetic food dye erythrosine in the brains of Wistar rats. Twenty-four 6- to 7-week-old female rats were randomly divided into four groups of six (n = 6); the control group and the other three groups, which were established on the basis of erythrosine's acceptable daily intake (ADI, 0.1 mg per kg body weight); 1/4 ADI, 1/2 ADI, and ADI; for 28 days. Significant alterations in the enzymatic activity of catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), and acetylcholinesterase (AchE) were observed at all erythrosine dosages, with a substantial decline at ADI dosages (p ≤ 0.05). Increased oxidative stress markers, viz., malondialdehyde content and lactate dehydrogenase activity, were observed in ADI-administered rats. The H2O2 content decreased at 1/4 ADI and 1/2 ADI dosages and thereafter increased with increasing dosage. The comet assay demonstrated that the ADI dosage for 28 days resulted in the most significant damage, as evidenced by the increased tail length, tail DNA percentage, and tail moment. Light microscopy revealed various anomalies in brain histology, such as atrophies, vacuolization, shrunken cells, pyknotic nuclei, and reduced cell density. The results of the present study demonstrated that erythrosine disrupts the normal histopathology of the brain, suppresses antioxidative and acetylcholinesterase enzymatic activity, and increases lipid peroxidation and DNA damage, thereby resulting in erythrosine toxicity even at doses lower than the ADI.

Highly sensitive colorimetric method for the detection of organophosphorus pesticides based on H2O2 etching of silver-coated gold nanostars

The residues of organophosphorus pesticides in agricultural production and soil constitute a significant threat to both human health and ecosystems, underscoring the critical importance of developing effective detection methods for these pesticides. Here, we introduce an innovative method for detecting trichlorfon that integrates hydrogen peroxide (H2O2)-induced etching of silver-coated gold nanostars (AuNS@Ag) with an enzymatic reaction cascade. By precisely controlling the thickness of the silver layer and the morphology of the gold nanoparticle core, we enhance the sensitivity of the H2O2 etching process. In this detection system, acetylcholinesterase (AChE) catalyzes the hydrolysis of acetylcholine chloride (ACh) into choline, which is then oxidized by choline oxidase (ChOx) to produce H2O2. The generated H2O2 subsequently etches the silver layer of AuNS@Ag, leading to a pronounced red-shift in the localized surface plasmon resonance (LSPR) wavelength, from 590 nm to 735 nm. However, the presence of trichlorfon inhibits the activity of AChE, resulting in a reduced production of H2O2 and a subsequent attenuation of the LSPR wavelength shift. Under optimized experimental conditions, this method enables the linear detection of trichlorfon within a concentration range of 0.1–5.0 μg mL−1 and has been successfully applied to detect trichlorfon in cabbage and tap water samples, showcasing its promising potential in food safety and environmental monitoring.

9. EFFECTS OF GLYCEMIC REGULATION AND ACETYLCHOLINESTERASE INHIBITION OF SCORPION TURMERIC (CURCUMA RANGJUED) IN CENTRAL HIGHLANDS, VIETNAM

Scorpion turmeric has been traditionally grown in the Central Highlands provinces of Vietnam. Prepared medicinal products from this species (Curcuma rangjued) are currently used in folk medicine to treat various illnesses including bronchitis, asthma, gastritis, and typically used as an antiseptic. Despite its popular use, scientific studies into its pharmacological properties remain limited. Chemical analysis has revealed the presence of many valuable bioactive ingredients such as D-limonene, β-pinene, and caryophyllene, which exhibit high pharmaceutical potential due to antioxidant and anti-inflammatory activities (Athanasaki et al., 2022). Therefore, exploiting the medicinal resource from the scorpion turmeric plant will bring various benefits to community health care. Objectives: This study aimed to evaluate the glycemic regulation and acetylcholinesterase (AChE) inhibitory effects of the scorpion turmeric’s rhizome extracts. Methods: Blood glucose levels were measured using the method described by Sivalingam (2013), while AChE inhibitory activity was determined according to the method of Ellman et al. (1961). Results: The results have shown that scorpion turmeric’s rhizome extracts which contain D-limonene, β-pinene and caryophyllene, demonstrated significant anti-inflammatory properties. Moreover, they exhibited both in vitro and in vivo glycemic regulatory effects and inhibited AChE activity in vitro. Conclusion: The findings of this study suggest that C. rangjued possess considerable therapeutic potential for the management of diabetes and Alzheimer's disease. Therefore, the scorpion turmeric plant should be given more attention and developed to preserve this valuable medicinal resource.

Chemical, In Cellulo, and In Silico Characterization of the Aminocholine Analogs of VG

V-type nerve agents are exceedingly toxic chemical warfare agents that irreversibly inhibit acetylcholinesterase (AChE), leading to acetylcholine accumulation in synapses and the disruption of neurotransmission. VG or O.O-diethyl S-(diethylamino)ethyl phosphorothiolate was the first compound of this class that was synthesized. The selenocholines (-Se-), cholines (-O-), and methylene-cholines (-CH2-) analogs of V-agents have been synthesized and their anti-AChE activities reported. Nevertheless, the aminocholine derivatives have not been pursued. Here, we have designed and synthesized a series of phosphorylated aminocholines analogs of VG that were characterized by NMR spectroscopy (H1, C13, P31, and TOCSY). Their pharmacological properties were analyzed in silico, while their toxicological properties were in vitro investigated using the SH-SY5Y cellular model. Despite the drug likeness of the new compounds, these fail to inhibit AChE in vitro and in cellulo. This may be partially explained by the fact that aminocholine is not a good leaving group compared to thiocholine. Remarkably, one of the compounds (P4) was found to even increase the activity of AChE. These compounds may serve as new nerve agent mimics that are safer alternatives for testing countermeasures. Importantly, P4 may act as a lead compound for developing a new class of alternative nerve agent pretreatments that are safer from pyridostigmine.

Rational design to enhance the catalytic activity of acetylcholinesterase and mitigate trichlorfon toxicity in vitro

Trichlorfon (TCF) is a widely used organophosphate pesticide whose inhibition of acetylcholinesterase (AChE) results in neurotoxicity and significant biosafety risks. Addressing these concerns requires effective strategies to mitigate TCF-induced toxicity and safeguard exposed organisms. In this study, we explored the potential of a catalytic activity enhanced Culex pipiens AChE mutant to mitigate TCF-induced cytotoxicity through rational design. A double-point mutant, M5 (I198M/Y249F), was developed by combining molecular dynamics (MD) simulations with structural feature analysis to reshape the active pocket, which demonstrated enhanced catalytic efficiency and maintained thermostability. Its functional activity and improved catalytic performance were further confirmed by activity staining on non-denaturing gels. The analysis of the catalytic mechanism and the reduction in Molecular Mechanics-Generalized Born Surface Area (MM/GBSA) free energy revealed an increase in substrate affinity for M5. Additionally, the application of exogenous M5 not only restored endogenous AChE activity in NIH/3T3 cells exposed to TCF but also reduced reactive oxygen species (ROS) accumulation and apoptosis, thereby improving cell viability. In silico studies indicate that the stable interaction between M5 and TCF promotes the targeted depletion of TCF, effectively neutralizing its toxic effects. These findings indicate that M5 has potential as an enzyme-based antidote for organophosphate pesticide, offering a novel strategy for protecting non-target species from pesticide-induced damage.

Repeated exposure to ethanol alters memory acquisition and neurotransmission parameters in zebrafish brain

Alcohol is widely consumed worldwide and its abuse can cause cognitive dysfunction, affecting memory and learning due to several neurophysiological changes. An imbalance in several neurotransmitters, including the cholinergic and glutamatergic systems, have been implicated in these effects. Zebrafish are sensitive to alcohol, respond to reward stimuli, and tolerate and exhibit withdrawal behaviors. Therefore, we investigated the effects of repetitive exposure to ethanol (REE) and the NMDA receptor antagonist dizocilpine (MK-801) on memory acquisition and glutamatergic and cholinergic neurotransmission. Memory was assessed using the inhibitory avoidance and object recognition tasks. Brain glutamate levels and the activity of Na+-dependent transporters were evaluated as indexes of glutamatergic activity, while acetylcholinesterase (AChE) and choline acetyltransferase (ChAT), enzyme activity were evaluated as indexes of cholinergic activity. Behavioral assessments showed that REE impaired aversive and spatial memory, an effect that MK-801 mimicked. Glutamate levels, but not transporter activity, were significantly lower in the REE group; similarly, REE increased the activity of AChE, but not ChAT, activity. These findings suggest that intermittent exposure to ethanol leads to impairments in zebrafish memory consolidation, and that these effects could be associated with alterations in parameters related to neurotransmission systems mediated by glutamate and acetylcholine. These results provide a better understanding of the neurophysiological and behavioral changes caused by repetitive alcohol use.

Prosopis africana extract inhibits critical enzymes associated with hypertension in vitro and in cyclosporine-induced hypertensive rats

ObjectiveThis study evaluated the antihypertensive properties of leaf extracts of Prosopis africana (PA) in vitro and in hypertensive rats. MethodsEthanol (ELPA) and differential solvent fractions [ethyl-acetate (EAPA), butanol (BLPA), and aqueous (ALPA)] were prepared using standard protocols. Hypertension was induced in female albino Wistar rats intraperitoneally using cyclosporine (25 mg/kg/day) while extracts were administered via oral route. Forty female rats were grouped into 5 (n = 8). Group 1 received 2 ml distilled water, Group 2: (cyclosporine + 2 ml distilled water); Group 3: cyclosporine + captopril (10 mg/kg/day); Group 4: cyclosporine + 1000 mg/kg ELPA and Group 5: cyclosporine + 1500 mg/kg ELPA. The blood pressure of anesthetized rats was measured using LabScribe coupled to a Lab-Trax-4/24T, and the activities of angiotensin-converting enzyme (ACE), arginase, phosphodiesterase-5 (PDE-5), acetylcholinesterase (AChE) and adenosine deaminase (ADA) were evaluated using standard methods. ResultsAll the fractions exerted significantly (p < 0.05) higher ACE inhibitory effect (ELPA = 64.36 ± 0.50%; EAPA = 86.31 ± 0.60%; BLPA= 85.28 ± 2.30 % ; ALPA= 82.27 ± 2.10 % ) than the reference, lisinopril (40.22±0.50 % ); while the butanol fraction (67.05±0.40 % ) showed higher PDE-5 inhibition than the reference, sildenafil (23.06±0.70 % ). Administration of cyclosporine caused notable (p < 0.05) elevation of systolic/diastolic blood (131.00 ± 1.22/93.25 ± 1.49 mmHg) pressure plus elevated heart rate when in comparison with the normotensive rats (106.25 ± 1.65/85.25 ± 1.18 mmHg). Treatment of hypertensive rats with ELPA significantly reduced elevated activities of ACE, PDE-5, AChE, and arginase to values that are not significantly (p < 0.05) different from those of the rats treated with the reference drug. ConclusionThis result could validate the use of P. africana as an antihypertensive agent in folklore.

A dual-signal sensing platform based on single atomic iron-nitrogen-carbon nanozyme for the detection of neurodegenerative disease-related bioactive molecules acetylcholinesterase and dopamine

In this work, a novel iron-nitrogen-carbon single-atom nanozyme (Fe-N800 SAzyme) with peroxidase-like activity was synthesized by doping Fe in zeolitic imidazolate frameworks (ZiF-8) and utilizing graphitic C3N4 (g-C3N4) as a nitrogen source in the pyrolysis process. Acetylcholine (ACh) was continuously oxidized by acetylcholinesterase (AChE) and choline oxidase (CHO) to generate H2O2 through an enzymatic cascade reaction. The interaction between Fe-N800 SAzyme and H2O2 led to the generation of reactive oxygen species (ROS) that could then oxidize 3,3’,5,5’-tetramethylbenzidine (TMB) to oxidized TMB (oxTMB), which exhibited an absorption peak at 650 nm. Lysozyme (LZ)-functionalized 5-methyl-2-thiouracil (MTU) gold/silver nanoclusters (Au/Ag/LZ-MTU), which exhibited a fluorescence peak at 610 nm, could be quenched by oxTMB through the inner filter effect (IFE). Dopamine (DA) was able to consume ROS and hinder the oxidation of TMB. Therefore, by monitoring the change of fluorescence at 610 nm and absorption at 650 nm, a dual signal fluorometric and colorimetric sensing platform for AChE and DA was established. The AChE activity was monitored through the variation of fluorescence (I610) or colorimetric (A650) intensity, which had a low limit of detection (LOD) of 0.057 U/L and 0.11 U/L, respectively. The fluorescence and colorimetric methods were also able to sensitively monitor the DA activity with a LOD of 0.83 μM and 2.7 μM, respectively. Finally, the developed method could satisfactorily quantify AChE and DA in human serum, whole blood, and DA hydrochloride injection samples.