Rat Brain Acetylcholinesterase Research Articles

Conjugates of nucleobases with triazole-hydroxamic acids for the reactivation of acetylcholinesterase and treatment of delayed neurodegeneration induced by organophosphate poisoning

A series of new uncharged conjugates of adenine, 3,6-dimetyl-, 1,6-dimethyl- and 6-methyluracil with 1,2,4-triazole-3-hydroxamic and 1,2,3-triazole-4-hydroxamic acid moieties were synthesized and studied as reactivators of organophosphate-inhibited cholinesterase. It is shown that triazole-hydroxamic acids can reactivate acetylcholinesterase (AChE) inhibited by paraoxon (POX) in vitro, offering reactivation constants comparable to those of pralidoxime (2-PAM). However, in contrast to 2-PAM, triazole-hydroxamic acids demonstrated the ability to reactivate AChE in the brain of rats poisoned with POX. At a dose of 200 mg/kg (i.v.), the lead compound 3e reactivated 22.6 ± 7.3% of brain AChE in rats poisoned with POX. In a rat model of POX-induced delayed neurodegeneration, compound 3e reduced the neuronal injury labeled with FJB upon double administration 1 and 3 h after poisoning. Compound 3e was also shown to prevent memory impairment of POX-poisoned rats as tested in a Morris water maze.

The Time Profile of the Effects of Moderate Hypothermia on Synaptic Acetylcholinesterase in Rat Brain.

Hypothermia in homeotherms significantly affects the neurotransmitter systems of the brain, including the cholinergic system. The function of the brain cholinergic system during prolonged moderate hypothermia is not known yet. We studied the effects of moderate hypothermia of various durations on the activity and kinetic parameters of synaptic acetylcholinesterase in rat brain. Immediately after body temperature decrease to 30°C, the efficiency of synaptic acetylcholinesterase catalysis significantly increases due to changes in both the maximum rate of reaction (Vmax; the rate of reaction when the enzyme is saturated with substrate) and Michaelis constant (Km). However, in the dynamics of prolonged hypothermia (1-3 h), it decreases to a level of intact animals, which was associated with normalization of the kinetic parameters of the enzyme. The detected changes in the kinetic parameters of the enzyme are compensatory and can be associated with both its reversible post-translational modifications and changes in the annular lipids.

In silico screening, TLC bioautography and in vivo studies of Zanthoxylum armatum DC. (Indian Prickly Ash) extract as a potential neuroprotective agent

Zanthoxylum armatum DC., a popular spice, and folklore medicine, is widely distributed throughout the Northeastern region of India and practiced by indigenous tribes as a remedy for digestive and nervous system disorders. The study aimed to assess the neuro-protective potentiality of Zanthoxylum armatum extract through different learning and memory paradigms against scopolamine-induced cognitive impairment. For the isolation of the compounds, coarsely powdered shade-dried fruits were extracted with ethanol by the cold maceration method. In silico studies were performed for the isolated compounds. TLC bioautographic enzyme assay was developed to screen acetylcholinesterase and butyrylcholinesterase inhibition by plant extract using donepezil, a known acetylcholinesterase inhibitor. Memory retention activities of ethanolic extract (100, 200, and 400 mg/kg; p.o.) were determined in-vivo , along with an estimation of whole-brain cholinesterase and antioxidant activity. Chromatographic analysis from chloroform fraction resulted in the isolation of three bio-active phytoconstituents, and structural elucidation identified them as β-sitosterol (ZA-01), Stigmasterol (ZA-02), and Lupeol (ZA-03). In silico molecular docking studies revealed stigmasterol has the minimum binding energy with acetylcholinesterase among all the isolated bioactive. The stability of the protein-ligand complex was found satisfactory after performing molecular dynamics simulation studies. Pre-treatment with extract significantly improved transfer latency in maze tests decreased rat brain acetylcholinesterase activity, and showed antioxidant potentiality against scopolamine-induced memory impairment. The combination of neuroprotective, anticholinesterase, and antioxidant effects shown by Z. armatum extract may be what makes it a nootropic drug. These are good signs for the search for natural nootropics from Z. armatum extract. Even so, more research with extracts and isolated compounds will be needed to make the traditional uses of the plant more scientifically sound. • Zanthoxylum armatum is evaluated for its potential as neuroprotective agent. • β-sitosterol, Stigmasterol and Lupeol were isolated from the plant extract. • In silico molecular docking and molecular dynamics simulations were performed. • TLC bioautography, in vivo animal tests showed good neuroprotective action of Zanthoxylum armatum extract.

Oxime Therapy for Brain AChE Reactivation and Neuroprotection after Organophosphate Poisoning.

One of the main problems in the treatment of poisoning with organophosphorus (OPs) inhibitors of acetylcholinesterase (AChE) is low ability of existing reactivators of AChE that are used as antidotes to cross the blood-brain barrier (BBB). In this work, modified cationic liposomes were developed that can penetrate through the BBB and deliver the reactivator of AChE pralidoxime chloride (2-PAM) into the brain. Liposomes were obtained on the basis of phosphatidylcholine and imidazolium surfactants. To obtain the composition optimized in terms of charge, stability, and toxicity, the molar ratio of surfactant/lipid was varied. For the systems, physicochemical parameters, release profiles of the substrates (rhodamine B, 2-PAM), hemolytic activity and ability to cause hemagglutination were evaluated. Screening of liposome penetration through the BBB, analysis of 2-PAM pharmacokinetics, and in vivo AChE reactivation showed that modified liposomes readily pass into the brain and reactivate brain AChE in rats poisoned with paraoxon (POX) by 25%. For the first time, an assessment was made of the ability of imidazolium liposomes loaded with 2-PAM to reduce the death of neurons in the brains of mice. It was shown that intravenous administration of liposomal 2-PAM can significantly reduce POX-induced neuronal death in the hippocampus.

Cloning and Expression of Rat Brain Acetylcholinesterase Enzyme in Escherichia coli

In this study, the gene region of rat (Rattus norvegicus) brain acetylcholinesterase enzyme was amplified in PCR with designed forward and reverse primers and it was ligated into a pET-SUMO vector under suitable conditions. This recombinant vector was transformed to competent Escherichia coli cells and it was grown in liquid LB medium including kanamycin. Colony PCR was performed from growing colony and PCR products were checked with agarose gel electrophoresis. The correct colonies were grown in a liquid medium for plasmid isolation. After plasmid isolation, these recombinant constructs were used for whether the gene inserts properly with cross-PCR. After determining the accuracy of the plasmid, recombinant vectors were transferred into the E. coli BL21 (DE3) cells to perform protein production. Cells were grown in IPTG induced larger media for hours. Enzyme activity and SDS-PAGE analysis were performed from homogenate for each treatment samples.

Neuroprotective potential of hydroethanolic hull extract of Juglans regia L. on isoprenaline induced oxidative damage in brain of Wistar rats.

The study was aimed at assessing isoprenaline (ISO) induced oxidative damage in brain of Wistar rats and its protection by hydroethanolic hull extract of Juglans regia. Administration of ISO significantly increases catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), malondialdehyde (MDA) and advanced oxidation protein product (AOPP) levels and significantly reduced activities of antioxidant status (TAS), total thiols (TTH), acetylcholinesterase (AChE), arylesterase (AE), and glutathione peroxidase (GPx) in rat brain. Histopathologically, neuronal degeneration, spongiosis and gliosis were seen in cerebral cortex after ISO administration. Pretreatment with hull extract restored TAS, TTH, AChE, CAT and SOD values. Additionally, significant reductions were noted in levels of MDA, AOPP, and severity of histomorphological changes in cerebral cortex following hull extract treatment. Altered antioxidant biomarkers along with histopathological changes indicate oxidative injury in rat brain following ISO administration. Repeated administration of J. regia hull extract demonstrating presence of neuroprotective properties against ISO induced oxidative damage in rat brain.

Kinetic characterization of rat brain acetylcholinesterase modulated by lead and cartap: the ameliorative effect of Citrus limon fruit juice.

Human exposure to heavy metals and pesticides is a worldwide major health problem. These environmental pollutants have been considered as the most neurotoxic agents and responsible to causing neurological toxicity. Plant-based therapeutic supplement may be used in the event of toxicity. Citrus limon contains several useful bioactive ingredients including flavonoids, dietary fiber, carotenoids, vitamins, pectin, minerals, and essential oils, which are responsible for its therapeutic potential. In the present investigation, we have studied the toxicity of heavy metals such as lead (Pb) and a carbamate pesticide such as cartap (Cp) on rat brain acetylcholinesterase (AChE). The chemical characterization of C.limon involved determination of total antioxidants and 2,2-diphenyl-1-picryl-hydrazyl-hydrate free radical scavenging activity using known methods. The AChE activity and its kinetic characterization were performed by assaying the enzyme activity at varying substrate concentrations, pH, temperature, and time of reaction. Its different kinetic parameters such as K i , V max, K m , K cat, and K cat/K m were determined by using standard procedures. The amelioration potential of the extract was evaluated on the neurotransmission system of rat brain AChE treated with Pb, Cp, and their combination (Pb-Cp), considering their 50% inhibitory concentration (IC50) values. The optimal activity of rat brain AChE was recorded at 25µg of protein, pH of 7.4, substrate concentration [S] of 0.5mM, and temperature of 37.4-40°C. The enzyme was stable for 10min when incubated at 37.4°C in vitro. The enzyme displayed 70% of its activity remaining even after 160min of incubation in this condition. It may be stable up to 1month when stored at-20°C. The IC50 values for Pb, Cp, and Pb-Cp were found to be 75, 2.9, and 5mM, respectively. Pb, Cp, and Pb-Cp inhibited the activity of rat brain AChE in the noncompetitive, mixed, and uncompetitive manners, respectively, with their respective K i values to be 675, 2.37, and 22.72mM. The results indicated that the Pb and Cp were able to cause significant alterations in the level and properties of AChE. However, the introduction of lemon juice on Pb- and Cp-treated AChE indicated protection of its activity from their adverse effects. The results may be useful in prospective therapeutic applications of lemon juice or as a food supplement to protect mammalian systems from adverse effects of these toxicants.

Adding value to polyvinylpolypyrrolidone winery residue: A resource of polyphenols with neuroprotective effects and ability to modulate type 2 diabetes-relevant enzymes

A polyphenols-rich extract was obtained from polyvinylpolypyrrolidone (PVPP) winery residue, and its neuroprotective effects and ability to modulate the kinetics of type 2 diabetes-relevant enzymes were characterized. The PVPP-white wine extract is a mixture of polyphenols (840.08 ± 161.25 µg/mg, dry weight) dominated by proanthocyanidins and hydroxycinnamic acids, affording strong antioxidant activity, as detected by the protection of membrane lipids against oxidation and superoxide radical anion scavenging activity. Regarding type 2 diabetes framework, the extract inhibits α-glucosidase (Ki = 166.9 µg/mL) and aldose reductase (Ki = 127.5 µg/mL) through non-competitive mechanisms. Despite the modest ability to inhibit rat brain acetylcholinesterase, it protects neuronal SH-SY5Y cells against oxidative damage promoted by glutamate, decreasing reactive oxygen species generation and preserving cell redox state. Thus, PVPP-white wine extract has potential to support the development of functional foods and/or nutraceuticals aiming neuroprotection and glucose homeostasis regulation, with high relevance in Alzheimeŕs disease and type 2 diabetes interlink.

Antiamnesic Potential of <i>Coccinia indica</i> (Linn.) Extract: A Mechanism Based Study

Coccinia indica Linn., a well explored traditional edible medicinal plant of North East region of India, is routinely used as folkloric medicine to treat neurological disorders associated with cognitive dysfunction. The objective of the study was to evaluate the antiamnesic activity of Coccinia indica fruit extract. Antiamnesic activity of Coccinia indica was studied in Elevated plus maze and Y-maze against scopolamine induced amnesia. Moreover, we studied the influence of Coccinia indica extract on whole brain acetyl cholinesterase enzyme. Ethanolic extracts of Coccinia indica (100, 200 and 400 mg/kg body weight) were administered to healthy adult Wistar rats for successive seven days and acquisition, retention and retrieval of spatial recognition memory was determined against scopolamine (1 mg/kg, i.p.) induced amnesia in-vivo. Further, whole brain acetylcholinesterase was estimated as per Elman’s method. Pre-treatment with Coccinia indica ethanolic extract significantly improved spatial learning and memory and decreased rat brain acetyl cholinesterase activity in a dose dependent manner and comparable with standard drug Donepezil. The results indicate that ethanolic extract of Coccinia indica might be a useful as natural source of antiamnesic drug to improve learning and memory deficit associated symptoms of dementia and Alzheimer’s patients.

Rat Brain Acetyl Cholinesterase as a Biomarker of Cadmium Induced Neurotoxicity

Cadmium as potential natural xenobiotics has been appeared to cross blood cerebrum obstruction and to antagonistically impact the action of AChE and subsequently the mind capacities. In the current investigation, we have assessed the effect of cadmium in vitro on the properties of AChE detached from rat brain.. The enzyme was found to be membrane bound and it could be successfully solubilized using 0.2% (v/v) Triton X-100, a nonionic detergent, in the extraction buffer (50mM Phosphate, pH 7.4). The enzyme was seen as exceptionally stable as long as one month when put away at - 20°C. This chemical displayed most extreme movement at pH 7.4.AChE when incubated at different temperatures for 5 min, displayed maximum activity at 37°C. Treatment with higher temperatures caused inactivation of enzyme activity. The enzyme followed a simple Michaelis-Menten curve when assayed at varying substrate concentration and yielded Km value to be 0.0370 mM. At the point when a fixed movement of AChE was tested in presence of various concentrations of cadmium, the catalyst action was forcefully diminished; the IC50 esteem being about 5.7mM. The compound when tested in nearness of cadmium at a focus equivalent to its IC50, lost its half movement in 77 min (t1/2 ).Cadmium was found to act as a noncompetitive inhibitor to the enzyme. These outcomes proposed that AChE from rat cerebrum may fill in as a critical biomarker of cadmium incited neurotoxicity. Keywords: Acetyl cholinesterase; Brain; Cadmium; Biochemical properties; Inhibition

In vitro antioxidant and cholinesterase inhibitory activities of methanolic fruit extract of Phyllanthus acidus.

BackgroundAlzheimer’s disease (AD) is a progressive neurodegenerative disorder clinically characterized by loss of memory and cognition. Cholinergic deficit and oxidative stress have been implicated in the pathogenesis of AD. Therefore, inhibition of acetylcholinesterase and oxidation are the two promising strategies in the development of drug for AD. Phyllanthus acidus, belonging to the family Euphorbiaceae, is a tree and has been used in traditional medicine to treat several pain, inflammatory and oxidative stress related disorders such as rheumatism, bronchitis, asthma, respiratory disorder, also important to promote intellect and enhance memory, thus supporting its possible anti-Alzheimer’s properties. In this study, P. acidus was evaluated for its cholinesterase inhibitory and antioxidant activities.MethodsIn this study, we evaluated the antioxidant potential and neuroprotective activity of P. acidus by assessing total phenol content (FCR assay), total flavonoid content, total antioxidant capacity, Fe3+ reducing power capacity, DPPH (2, 2-diphenyl-1-picrylhydrazyl) and hydroxyl radical scavenging capacity, lipid peroxidation inhibition activity & metal chelating activity. In addition acetylcholinestrase (AChE) and butyrylcholinestrase (BChE) inhibitory activities were performed using Ellman’s method.ResultsTotal phenolic content and total flavonoid content of the extract were 116.98 mg of gallic acid equivalent and 168.24 mg of quercetin equivalent per gm of dried extract. The methanolic extract of P. acidus (MEPA) showed considerable total antioxidant activity and reducing capacity. In DPPH scavenging assay and hydroxyl radical scavenging assay, the MEPA showed 84.33 % and 77.21 % scavenging having IC50 of 15.62 and 59.74 μg/ml respectively. In lipid peroxidation inhibition activity MEPA showed moderate inhibition of peroxidation at all concentrations with IC50 value of 471.63 μg/ml and exhibited metal chelating activity with IC50 value 308.67 μg/ml. The MEPA exhibited inhibition of rat brain acetylcholinesterase and human blood butyrylcholinesterase in a dose dependent manner and the IC50 value was found to be 1009.87 μg/ml and 449.51 μg/ml respectively.ConclusionThese results of the present study reveal that MEPA has considerable amount of antioxidant activity as well as anti-acetylcholinesterase and anti-butyrylcholinesterase activity which suggest its effectiveness against Alzheimer's disease and other neurodegenerative disorders.

A comparison of the reactivating and therapeutic efficacy of two novel bispyridinium oximes (K727, K733) with the oxime HI-6 and obidoxime in sarin-poisoned rats and mice

The ability of two novel bispyridinium oximes K727 and K733 and currently available oximes (HI-6, obidoxime) to reactivate sarin-inhibited acetylcholinesterase and to reduce acute toxicity of sarin was evaluated. To investigate the reactivating efficacy of the oximes, the rats were administered intramuscularly with atropine and oximes in equitoxic doses corresponding to 5% of their LD50 values at 1 min after the intramuscular administration of sarin at a dose of 24 µg/kg (LD50). The activity of acetylcholinesterase was measured at 60 min after sarin poisoning. The LD50 value of sarin in non-treated and treated mice was assessed using probit-logarithmical analysis of death occurring within 24 h after intramuscular administration of sarin at five different doses. In vivo determined percentage of reactivation of sarin-inhibited rat blood, diaphragm and brain acetylcholinesterase showed that the potency of both novel oximes K727 and K733 to reactivate sarin-inhibited acetylcholinesterase roughly corresponds to the reactivating efficacy of obidoxime. On the other hand, the oxime HI-6 was found to be the most efficient reactivator of sarin-inhibited acetylcholinesterase. While the oxime HI-6 was able to reduce the acute toxicity of sarin >3 times, both novel oximes and obidoxime decreased the acute toxicity of sarin <2 times. Based on the results, we can conclude that the reactivating and therapeutic efficacy of both novel oximes K727 and K733 is significantly lower compared to the oxime HI-6 and, therefore, they are not suitable for the replacement of the oxime HI-6 for the antidotal treatment of acute sarin poisoning.

Nootropic activity of Crataeva nurvala Buch-Ham against scopolamine induced cognitive impairment.

Loss of cognition is one of the age related mental problems and a characteristic symptom of neurodegenerative disorders like Alzheimer’s. Crataeva nurvala Buch-Ham, a well explored traditional Indian medicinal plant of Westernghats, is routinely used as folkloric medicine to treat various ailments in particular urolithiasis and neurological disorders associated with cognitive dysfunction. The objective of the study was to evaluate the nootropic activity of Crataeva nurvala Buch-Ham stem bark in different learning and memory paradigm viz. Elevated plus maze and Y-maze against scopolamine induced cognitive impairment. Moreover, to elucidate possible mechanism, we studied the influence of Crataeva nurvala ethanolic extract on central cholinergic activity via estimating the whole brain acetyl cholinesterase enzyme. Ethanolic extracts of Crataeva nurvala (100, 200 and 400 mg/kg body weight) were administered to adult Wistar rats for successive seven days and the acquisition, retention and retrieval of spatial recognition memory was determined against scopolamine (1 mg/kg, i.p.) induced amnesia through exteroceptive behavioral models viz. Elevated plus maze and Y-maze models. Further, whole brain acetyl cholinesterase enzyme was estimated through Ellman’s method. Pretreatment with Crataeva nurvala ethanolic extract significantly improved spatial learning and memory against scopolamine induced amnesia. Moreover, Crataeva nurvala extract decreased rat brain acetyl cholinesterase activity in a dose dependent manner and comparable to the standard drug Piracetam. The results indicate that ethanolic extract of Crataeva nurvala might be a useful as nootropic agent to delay the onset and reduce the severity of symptoms associated with dementia and Alzheimer’s disease. The underlying mechanism of action of its nootropic potentiality might be attributed to its anticholinesterase property.

In vivo and in vitro effects of fructose on rat brain acetylcholinesterase activity: an ontogenetic study.

Increased fructose concentrations are the biochemical hallmark of fructosemia, a group of inherited disorders on the metabolic pathway of this sugar. The main clinical findings observed in patients affected by fructosemia include neurological abnormalities with developmental delay, whose pathophysiology is still undefined. In the present work we investigated the in vitro and in vivo effects of fructose on acetylcholinesterase (AchE) activity in brain structures of developing rats. For the in vitro experiments, fructose was added at increasing concentrations to the incubation medium. It was observed that fructose provoked an inhibition of acetylcholinesterase activity in cerebral cortex of 30-day-old-rats, even at low concentrations (0.1 mM). For the in vivo experiments, rats were killed 1 h after a single fructose administration (5 µmol/g). Control group received the same volume of saline solution. We found that AchE activity was increased in cerebral cortex of 30- and 60-day-old rats receiving fructose administration. Finally, we observed that AchE activity was unaffected by acute fructose administration in cerebral cortex, striatum or hippocampus of 15- and 90-day-old rats. The present data suggest that a disruption in cholinergic homeostasis may be involved in the pathophysiology of brain damage observed in young patients affected by fructosemia.

Neuroprotective potential of sesamol and its loaded solid lipid nanoparticles in ICV-STZ-induced cognitive deficits: Behavioral and biochemical evidence

Neuroinflammation is a prominent feature of Alzheimer disease (AD) and other chronic neurodegenerative disorders. Intracerebroventricular (ICV) streptozotocin (STZ) induced-cognitive impairment has been widely used as an experimental paradigm of Alzheimer׳s disease. Sesamol is a potent inhibitor of cytokine production as well as an antioxidant. The present study was designed to evaluate the effectiveness of sesamol in ICV-STZ-induced cognitive deficits in rats by incorporating it into solid lipid nanoparticles (SLNs). ICV-STZ administration produced significant cognitive deficits as assessed by both Morris water maze and elevated plus maze task which is accompanied by significantly enhanced nitrodative stress, altered acetylcholinesterase in rat brain along with significantly increased serum TNF-α levels. Chronic treatment with sesamol and sesamol loaded SLNs dose dependently restored cognitive deficits in ICV-STZ rats along with mitigation of nitrodative stress and cytokine release. Effectiveness of SLNs to deliver sesamol to the brain was shown by a significantly better alleviation of the oxidative stress parameters. Our findings demonstrate that loading of sesamol in SLNs is an effective strategy to mitigate ICV-STZ-induced neuronal dysfunction and memory deficits.

Pd(II) complexes of acetylcholinesterase reactivator obidoxime.

The ability of the acetylcholinesterase reactivator obidoxime (H2L2+) to bind palladium(II) cations was evaluated spectrophotometrically at different reaction conditions (pH, reaction time, metal-to-ligand molar ratio). The results showed that immediately after mixing the reagents, pH 7.4, complex species of composition [PdHL]3+ existed predominantly with a value of conditional stability constant lgβ‘=6.52. The reaction was completed within 24 hours affording the formation of species [Pd2L]4+ with significantly increased stability (lgβ‘=9.34). The spectral data suggest that obidoxime coordinates metal(II) ions through the oximate functional groups. The in vitro reactivation assay of paraoxon-inhibited rat brain acetylcholinesterase revealed that the new complex species were much less active than the non-coordinated obidoxime. The lack of reactivation ability could be explained by the considerable stability of complexes in solution as well as by the deprotonation of oxime groups essential for recovery of the enzymatic activity.

In vitro Reactivation of Chlorpyrifos-inhibited Rat Brain Acetylcholinesterase from 2-Quinolone Substituted Thiazole derivatives

Organophosphate (OP) compounds exert inhibition of acetylcholinesterase (AChE) by irreversibly binding to catalytic site of an enzyme. Despite continued efforts to discover improved reactivators, there has been little success towards innovation of AChE reactivators. In the present investigation, new series of 2-quinolone fused thiazole derivatives 3a-3f and 4a-4f were evaluated for their in vitro reactivation efficacy against chlorpyrifos inhibited AChE using 2-PAM as standard. Even though the non oxime derivatives were not as effective as pralidoxime (2-PAM), but exhibited considerable AChE reactivation. The compounds, 3b, 3c, 3f, and 4f, showed promising reactivation against chlorpyrifos inhibited AChE.

A comparison of the reactivating and therapeutic efficacy of two novel oximes K378 and K458 with currently available oximes in rats and mice poisoned with sarin

The ability of two novel oximes K378 and K348 and currently available oximes (HI-6, obidoxime) to reactivate sarin-inhibited acetylcholinesterase and to reduce acute toxicity of sarin was evaluated. Both new potential oxime reactivators were chosen for this study based on the data obtained during the extensive work on oximes development, from structure–activity relationship studies and in vitro evaluation of their ability to reactivate acetylcholinesterase inhibited by organophosphorus compounds. In vivo determined percentage of reactivation of sarin-inhibited rat blood and brain acetylcholinesterase showed that the potency of both novel oximes K378 and K458 to reactivate sarin-inhibited acetylcholinesterase roughly corresponds to low reactivating efficacy of obidoxime. On the other hand, the oxime HI-6 was found to be efficient reactivator of sarin-inhibited acetylcholinesterase in the peripheral compartment. While the oxime HI-6 was able to reduce the acute toxicity of sarin more than three times, both novel oximes decreased the acute toxicity of sarin less than two times. Based on the results, we can conclude that reactivating and therapeutic efficacy of both novel oximes K378 and K458 are significantly lower compared to the oxime HI-6 and, therefore, it is not suitable to replace the oxime HI-6 for the antidotal treatment of acute sarin poisoning.

Rosmarinus officinalis L. leaf extract improves memory impairment and affects acetylcholinesterase and butyrylcholinesterase activities in rat brain

Rosmarinus officinalis L. leaf as part of a diet and medication can be a valuable proposal for the prevention and treatment of dementia. The aim of the study was to assess the effects of subchronic (28-fold) administration of a plant extract (RE) (200mg/kg, p.o.) on behavioral and cognitive responses of rats linked with acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity and their mRNA expression level in the hippocampus and frontal cortex. The passive avoidance test results showed that RE improved long-term memory in scopolamine-induced rats. The extract inhibited the AChE activity and showed a stimulatory effect on BuChE in both parts of rat brain. Moreover, RE produced a lower mRNA BuChE expression in the cortex and simultaneously an increase in the hippocampus. The study suggests that RE led to improved long-term memory in rats, which can be partially explained by its inhibition of AChE activity in rat brain.

80 : Novel multi-functional drugs for the treatment of neurodegenerative diseases

Oxidative stress (OS), glial activation and formation of plaques and tangles are believed to contribute to progressive neurodegeneration in Alzheimer’s disease (AD). None of the acetylcholinesterase (AChE) inhibitors currently in clinical use are able to reduce OS and inflammatory processes at doses used to treat AD. Therefore, there is a need for a drug which inhibits AChE and butyrylcholinesterase (BuChE), has anti-oxidant and anti-inflammatory activities. Indole propionic acid (IPA) prevents oxidative stress and death of primary neurons and neuroblastoma cells exposed to H2O2 or amyloid beta. Derivatives of indoline propionic acid (InPA) were found to be more potent anti-oxidants than those of IPA in cell culture. Therefore, a series of novel carbamates was synthesized based on the structure of InPA and their AChE, BuChE, anti-oxidant and anti-inflammatory activities were evaluated. Three compounds: Indoline-4-ylethyl methyl carbamate (AN-854), 3-(2-(methoxycarbonyl) ethyl) indolin-4-ylethyl methyl carbamate (AN-827) and 3-(2-(methoxycarbonyl) ethyl)-1-indoline-6-ylethyl methyl carbamate (AN-680) prevented cytotoxicity induced by OS and the release of cytokines from activated microglial cells at concentrations at, or lower than those inhibiting AChE. They inhibited AChE in rat brain and reduced lipid peroxidation and formation of nitrites in mouse brain after injection of lipopolysaccharide (LPS). When injected together with LPS they lowered the levels of COX-2 and pro-inflammatory cytokines (IL-6, IL-1β and TNF-α) in the brain and spleen. The mechanism of anti-inflammatory activity was evaluated in BV2 cells activated with LPS and shown to occur through reduction in phosphorylation of p38 and activation of the transcription factor AP-1. Conclusion: Indoline derivatives which display anti-oxidant and anti-inflammatory and cholinesterase inhibitory activities in vitro and in vivo, may have potential use for the treatment of AD and other neurodegenerative diseases.