Scopolamine-induced Cognitive Impairment Research Articles

Antiamnesic effects of tofisopam against scopolamine-induced cognitive impairments in rats

In this study, we investigated the potential therapeutic effects of tofisopam, a 2,3-benzodiazepine derivative anxiolytic, on cognitive deficits in rats with scopolamine-induced amnesia. Cognitive performance of the rats was investigated by using the Morris water maze and passive avoidance tests. Changes in motor activity were assessed by using the activity cage and Rota-rod tests and then morphological changes in the hippocampus were assessed via immunohistochemical stainings. The results indicated that scopolamine impaired learning and memory parameters in rats. Worsened cognitive performance, neuronal loss, and decreased hippocampal synaptophysin, Ki-67, and glial fibrillary acidic protein density were observed. Tofisopam administration at a dose of 50 mg/kg for seven days improved the impaired cognitive performance, enhanced the attenuated synaptic transmission in the hippocampus, increased proliferation in subgranular zones, and improved the decrease in astrocytes in amnesic rats. These findings point out the anti-amnesic effects of tofisopam with concomitant improvements in the hippocampal synaptogenesis, neurogenesis, and glial plasticity, for the first time. Presented beneficial effects of tofisopam on cognitive dysfunctions may have a notable clinical value considering the fact that one of the most important side effects of 1,4-benzodiazepines, which are classical anxiolytic drugs, is amnesia. However, these preclinical results need to be confirmed with further clinical studies, first.

FA-97, a New Synthetic Caffeic Acid Phenethyl Ester Derivative, Protects against Oxidative Stress-Mediated Neuronal Cell Apoptosis and Scopolamine-Induced Cognitive Impairment by Activating Nrf2/HO-1 Signaling.

Alzheimer's disease (AD) is an age-related neurodegenerative disorder with cognitive deficits, which is becoming markedly more common in the world. Currently, the exact cause of AD is still unclear, and no curative therapy is available for preventing or mitigating the disease progression. Caffeic acid phenethyl ester (CAPE), a natural phenolic compound derived from honeybee hive propolis, has been reported as a potential therapeutic agent against AD, while its application is limited due to the low water solubility and poor bioavailability. Here, caffeic acid phenethyl ester 4-O-glucoside (FA-97) is synthesized. We validate that FA-97 attenuates H2O2-induced apoptosis in SH-SY5Y and PC12 cells and suppresses H2O2-induced oxidative stress by inhibiting the ROS level, malondialdehyde (MDA) level, and protein carbonylation level, as well as induces cellular glutathione (GSH) and superoxide dismutase (SOD). Mechanistically, FA-97 promotes the nuclear translocation and transcriptional activity of Nrf2 associated with the upregulated expression of HO-1 and NQO-1. The prime importance of Nrf2 activation in the neuroprotective and antioxidant effects of FA-97 is verified by Nrf2 siRNA transfection. In addition, FA-97 prevents scopolamine- (SCOP-) induced learning and memory impairments in vivo via reducing neuronal apoptosis and protecting against cholinergic system dysfunction in the hippocampus and cortex. Moreover, the increased MDA level and low total antioxidant capacity in SCOP-treated mouse brains are reversed by FA-97, with the increased expression of HO-1, NQO-1, and nuclear Nrf2. In conclusion, FA-97 protects against oxidative stress-mediated neuronal cell apoptosis and SCOP-induced cognitive impairment by activating Nrf2/HO-1 signaling, which might be developed as a therapeutic drug for AD.

Possible neuroprotective effect of cholorogenic acid and protocatechuic acid combinational approach against scopolamine-induced cognitive impairment in a mouse model as a multitargeted ligand

Possible neuroprotective effect of cholorogenic acid and protocatechuic acid combinational approach against scopolamine-induced cognitive impairment in a mouse model as a multitargeted ligand

Synergistic Neuroprotective Effect of Schisandra chinensis and Ribes fasciculatum on Neuronal Cell Death and Scopolamine-Induced Cognitive Impairment in Rats.

Mild cognitive impairment (MCI) is considered as a transitional stage between aging and Alzheimer’s disease. In the present study, we examined the protective effect of Schisandra chinensis (SC) and Ribes fasciculatum (RF) on neuronal cell death in vitro and scopolamine-induced cognitive impairment in Sprague Dawley® rats in vivo. A mixture of SC and RF extracts (SC+RF) significantly protected against hydrogen peroxide-induced PC12 neuronal cell death. The neuroprotective effect of SC+RF on scopolamine-induced memory impairment in rats was evaluated using the passive avoidance test and the Morris water maze test. In the passive avoidance test, SC+RF-treated rats showed an increased latency to escape, compared to the scopolamine-treated rats. Moreover, SC+RF treatment significantly reduced escape latency in water maze test, compared to treatment with scopolamine alone. To verify the long-term memory, we performed probe test of water maze test. As a result, rat treated with SC+RF spent more time in the target quadrant. Consistent with enhancement of memory function, the brain derived neurotrophic factor (BDNF) and its downstream molecules (pERK, pATK, and pCREB) are increased in SC+RF treatment in hippocampal area compared with scopolamine treated group. These results suggest that a mixture of SC and RF extracts may be a good therapeutic candidate for preventing mild cognitive impairment.

Danshensu attenuates scopolamine and amyloid-β-induced cognitive impairments through the activation of PKA-CREB signaling in mice

Alzheimer's disease (AD) is an important chronic neurodegenerative disorder and is mainly associated with cognitive dysfunction. At present, bioactive compounds from traditional medicinal plants have received much attention for the enhancement of cognitive function. Danshensu, a phenolic acid isolated from herbal medicines, has various pharmacological activities in the central nervous system, including anxiolytic-like and neuroprotective properties. The present study aimed to investigate the ameliorating effects of danshensu on scopolamine- and amyloid-β (Aβ) protein-induced cognitive impairments in mice. Danshensu (3 and 10 mg/kg, p.o.) effectively ameliorated scopolamine-induced cognitive dysfunction in mice, as measured in passive avoidance and Y-maze tasks. In a mechanistic study, danshensu inhibited monoamine oxidase A (MAO-A) activity but not MAO-B. Additionally, danshensu treatment increased the dopamine level and the phosphorylation levels of protein kinase A (PKA) and cAMP response element binding protein (CREB), in the cortex of the brain. Furthermore, the ameliorating effect of danshensu against scopolamine-induced cognitive impairment was fully blocked by H89, a PKA inhibitor. Finally, danshensu also ameliorated Aβ-induced cognitive impairments in an animal model of AD. The results revealed that danshensu treatment significantly improved scopolamine and Aβ-induced cognitive impairments in mice by facilitation of dopamine signaling cascade such as PKA and CREB due to MAO-A inhibition. Thus, danshensu could be used as a promising therapeutic agent for preventing and treating AD.

Reduced systemic exposure and brain uptake of donepezil in rats with scopolamine-induced cognitive impairment

1. Donepezil (DPZ) is an acetylcholinesterase (AchE) inhibitor used in the mild to moderately severe Alzheimer’s disease. Among its major metabolites, 6-O-desmethyl DPZ (6-DDPZ), 5-O-desmethyl DPZ (5-DDPZ) and DPZ N-oxide, the anti-AchE activities of 5-DDPZ and DPZ N-oxide have never been clearly identified before. Besides, there is no report on simultaneous determination of DPZ and its three metabolites in the brain, thus their uptake in hippocampus and cortex are unknown. Therefore, the current studies are proposed aiming to: (1) investigate the anti-AchE activities and brain uptake of DPZ and its three metabolites and (2) compare their pharmacokinetics and brain uptake between normal and scopolamine-induced rats.2. DPZ and its three metabolites demonstrated anti-AchE activities with the IC50 in the order of DPZ (7.20 × 10−2 μM), 6-DDPZ (1.14 × 10−1 μM), 5-DDPZ (4.03 × 10−1 μM) and DPZ N-oxide (1.61 μM). They were also evenly distributed in the brain and retained much longer in the brain than that in plasma in normal rats.3. Compared to normal rats, Cmax, AUC0→24h and AUC0→∞ of DPZ were reduced by 52.0%, 31.2% and 30.1%, respectively; Tmax of DPZ and its three metabolites were prolonged and their brain uptake were decreased in scopolamine-induced rats, suggesting the potential reduced absorption of DPZ.

Isoorientin improves scopolamine-induced cognitive impairments by restoring the cholinergic system, antioxidant defense, and p-CREB/BDNF signaling in the hippocampus and frontal cortex.

Isoorientin (ISO) is considered one of the most important flavonoids with various pharmacological effects such as antioxidant, anti-inflammatory, and anti-cancer activities. Despite these beneficial activities, the effects of ISO on learning and memory have not been investigated so far. The current study evaluated the memory-enhancing effects of ISO in a scopolamine-treated mouse model by using the Y-maze and passive avoidance tests. The results showed that ISO (5 and 10mg/kg, p.o.) treatment significantly improved the cognitive impairments caused by scopolamine. Additionally, ISO significantly decreased scopolamine-induced acetylcholinesterase and thiobarbituric acid reactive substance activities in both the hippocampus and frontal cortex of mice. In addition, ISO significantly increased the levels of total superoxide dismutase induced by scopolamine in the hippocampus and frontal cortex. Moreover, Western blot results indicated that ISO reversed the decreases in expression of phosphorylated cAMP response element binding (CREB) and brain-derived neurotrophic factor (BDNF) in the hippocampus and frontal cortex of scopolamine-treated mice. Thus, our results provide initial evidence that ISO ameliorates scopolamine-induced memory and cognitive impairments partly by restoring the cholinergic system, antioxidant defense, and p-CREB/BDNF signaling pathway, thereby exhibiting memory-enhancing activities.

In Vivo Pharmacological Comparison of TAK-071, a Positive Allosteric Modulator of Muscarinic M1 Receptor, and Xanomeline, an Agonist of Muscarinic M1/M4 Receptor, in Rodents

Activation of the M1 muscarinic acetylcholine receptor (M1R) may be an effective therapeutic approach for Alzheimer's disease (AD), dementia with Lewy bodies, and schizophrenia. Previously, the M1R/M4R agonist xanomeline was shown to improve cognitive function and exert antipsychotic effects in patients with AD and schizophrenia. However, its clinical development was discontinued because of its cholinomimetic side effects. We compared in vivo pharmacological profiles of a novel M1R-selective positive allosteric modulator, TAK-071, and xanomeline in rodents. Xanomeline suppressed both methamphetamine- and MK-801-induced hyperlocomotion in mice, whereas TAK-071 suppressed only MK-801-induced hyperlocomotion. In a previous study, we showed that TAK-071 improved scopolamine-induced cognitive deficits in a rat novel object recognition task (NORT) with 33-fold margins versus cholinergic side effects (diarrhea). Xanomeline also improved scopolamine-induced cognitive impairments in a NORT; however, it had no margin versus cholinergic side effects (e.g., diarrhea, salivation, and hypoactivity) in rats. These side effects were observed even in M1R knockout mice. Evaluation of c-Fos expression as a marker of neural activation revealed that xanomeline increased the number of c-Fos-positive cells in several cortical areas, the hippocampal formation, amygdala, and nucleus accumbens. Other than in the orbital cortex and claustrum, TAK-071 induced similar c-Fos expression patterns. When donepezil was co-administered to increase the levels of acetylcholine, the number of TAK-071-induced c-Fos-positive cells in these brain regions was increased. TAK-071, through induction of similar neural activation as that seen with xanomeline, may produce procognitive and antipsychotic effects with improved cholinergic side effects.

Fermented rice peptides attenuate scopolamine-induced memory impairment in mice by regulating neurotrophic signaling pathways in the hippocampus

This study investigated the preventive effects of fermented rice peptides (FRPs) against scopolamine-induced memory impairment in mice and their potential mechanisms. Mice were pretreated with FRPs (25 and 100 mg/kg body weight) via intraperitoneal injection for 7 days, followed by intraperitoneal injection of scopolamine. FRP pretreatment suppressed scopolamine-induced cognitive impairment in passive-avoidance test and significantly upregulated levels of brain-derived neurotrophic factor (BDNF) and induced the phosphorylation of cAMP response element binding (CREB) protein and extracellular signal-regulated kinase (ERK) in the hippocampus of scopolamine-treated mice. Additionally, scopolamine-treated mice showed significantly decreased acetylcholine levels and increased acetylcholine-esterase activity in the hippocampus as compared with controls; however, these changes were suppressed by FRP pretreatment. Among the fractions separated by size-exclusion chromatography, the non-glycosylated peptide fraction of FRP suppressed H2O2-induced neuronal damage in SK-N-SH cells via upregulated BDNF levels. Our findings demonstrated that FRP prevented memory impairment, and that the underlying mechanism might involve regulation of the ERK/CREB/BDNF signaling pathway. These results suggest FRP as a potential agent for the prevention of age-related cognitive decline and dementia.

Effect of Aged Garlic Ethyl Acetate Extract on Oxidative Stress and Cholinergic Function of Scopolamine-Induced Cognitive Impairment in Mice.

This study was performed to investigate the effect of aged black garlic ethyl acetate extract on scopolamine-induced cognitive impairment in mice. Aged garlic ethyl acetate extract (BG) was administrated at a dose of 25 or 50 mg/ kg in scopolamine-induced mice. Cognitive ability was evaluated using a Morris water maze test and a passive avoidance test. BGs (50 mg/kg) shortened the latency time that was increased by scopolamine and increased the platform crossing numbers that was significantly shortened by scopolamine after 5 days training in the Morris water maze test (P<0.05). BG (50 mg/kg) also significantly prolonged the latency time in the passive avoidance test (P<0.05). Result from biochemical analysis showed that BG increased levels of glutathione, glutathione peroxidase activity, and glutathione reductase activity, whereas BG significantly inhibited lipid peroxidation (P<0.05). BG also attenuated cholinergic degradation through inhibiting acetylcholinesterase activity and increasing choline acetyltransferase activity (P<0.05). In conclusion, BG protected against scopolamine-induced cognitive impairment through decreasing oxidative damage and regulating cholinergic function in the brains of mice. BG may therefore be a beneficial food for protecting against neurodegeneration such as Alzheimer’s disease.

Design, synthesis, in-silico and biological evaluation of novel chalcone-O-carbamate derivatives as multifunctional agents for the treatment of Alzheimer's disease

To discover multifunctional agents for the treatment of Alzheimer's disease (AD), a series of chalcone-O-carbamate derivatives was designed and synthesized based on the multitarget-directed ligands strategy. The in vitro biological activities were evaluated including AChE/BChE inhibition, MAO-A/MAO-B inhibition, antioxidant activities, Aβ1-42 aggregation inhibition, metal-chelating properties and neuroprotective effects against H2O2-induced PC12 cell injury. The results showed compounds 5b and 5h indicated highly selective BChE inhibitory activity with IC50 values of 3.1 μM and 1.2 μM, respectively and showed highly selective MAO-B inhibitory potency with IC50 values of 1.3 μM and 3.7 μM, respectively. In addition, compounds 5b and 5h could inhibit self-induced Aβ1-42 aggregation with 63.9% and 53.1% inhibition percent rate, respectively. Particularly, compound 5b was a potent antioxidant agent and neuroprotectant, as well as a selective metal chelator by chelating Cu2+ and Al3+. Moreover, compound 5b could inhibit and disaggregate Cu2+-induced Aβ1-42 aggregation, which was further supported by the TEM images. Furthermore, compounds 5b and 5h could cross the blood-brain barrier (BBB) in vitro and conformed to the Lipinski's rule of five. Finally, the in vivo assay exhibited that compound 5b could improve scopolamine-induced cognitive impairment. Taken together, these results revealed that compound 5b might be a potential multifunctional agent for the treatment of AD, and deserved to do further structure optimization.

The Ameliorating Effects of Bee Pollen on Scopolamine-Induced Cognitive Impairment in Mice.

Bee pollen consists of floral pollen mixed with bee secretions and nectar. It has been considered as a functional food and has different kinds of biologically active ingredients, such as flavonoids, polyphenols, phytosterols and minerals. However, its function in cognition has yet been investigated. In the present study, we investigated the ameliorating effect of bee pollen against scopolamine-caused cognitive impairment through the passive avoidance test, the Y-maze test and the Morris water maze test. In addition, Western blotting was employed to verify the effects of bee pollen on memory-related signaling molecules in the hippocampus. Bee pollen extract (100 or 300 mg/kg, per os (p.o.)) obviously reversed scopolamine-caused cognitive impairment in the passive avoidance test, ameliorated spontaneous alternation versus the scopolamine-treated group in the Y-maze test and prolonged swimming time in the target zone in the Morris water maze test. In addition, the phosphorylation levels of extracellular signal-regulated kinase (ERK), cAMP response element-binding protein (CREB), protein kinase B (Akt) and glycogen synthase kinase-3β (GSK-3β), and the expression levels of brain-derived neurotrophic factor (BDNF) and tissue plasminogen activator (tPA) in the hippocampi, were increased in response to the treatment with bee pollen extract (100 or 300 mg/kg, p.o.). These results indicated that bee pollen ameliorates cognitive impairment induced by cholinergic blockade through the enhancing conversion of proBDNF to mature BDNF by tPA, probably, through the ERK-CREB pathway or Akt-GSK-3β signaling pathway and would be a useful agent for the treatment of cognitive dysfunction.

Design and development of multitarget-directed N-Benzylpiperidine analogs as potential candidates for the treatment of Alzheimer's disease

The multitarget-directed strategy offers an effective and promising paradigm to treat the complex neurodegenerative disorder, such as Alzheimer's disease (AD). Herein, a series of N-benzylpiperidine analogs (17–31 and 32–46) were designed and synthesized as multi-functional inhibitors of acetylcholinesterase (AChE) and β-secretase-1 (BACE-1) with moderate to excellent inhibitory activities. Among the tested inhibitors, 25, 26, 40, and 41 presented the most significant and balanced inhibition against both the targets. Compounds 40 and 41 exhibited high brain permeability in the PAMPA-BBB assay, significant displacement of propidium iodide from the peripheral anionic site (PAS) of AChE, and were devoid of neurotoxicity towards SH-SY5Y neuroblastoma cell lines up to the maximum tested concentration of 80 μM. Meanwhile, both these compounds inhibited self- and AChE-induced Aβ aggregation in thioflavin T assay, which was also re-affirmed by morphological characterization of Aβ aggregates using atomic force microscopy (AFM). Moreover, 40 and 41 ameliorated the scopolamine-induced cognitive impairment in elevated plus and Y-maze experiments. Ex vivo and biochemical analysis established the brain AChE inhibitory potential and antioxidant properties of these compounds. Further, improvement in Aβ1-42-induced cognitive impairment was also observed by compound 41 in the Morris water maze experiment with significant oral absorption characteristics ascertained by the pharmacokinetic studies.

Hydroxy-α-sanshool isolated from Zanthoxylum bungeanum attenuates learning and memory impairments in scopolamine-treated mice.

Learning and memory impairments are common symptoms of dementia in neurodegenerative disorders. Occasionally, we found that Zanthoxylum bungeanum pericarps (ZBP) significantly activated the spontaneous activity of the hippocampus (HIPP) and paraHIPP (P < 0.001, uncorrected), implying the potential ability of ZBP to improve cognitive impairments. Thus, this study aimed to investigate the improving effect of hydroxy-α-sanshool (HAS), a characteristic ingredient of ZBP, against scopolamine (1 mg kg-1, i.p.)-induced learning and memory deficits. HAS (5 mg kg-1, p.o.) markedly reversed scopolamine-induced cognitive impairments, as indicated by its performance in the passive avoidance test and Morris water maze test (P < 0.01). Furthermore, HAS (2.5 and 5.0 mg kg-1, p.o.) also dose-dependently prevented changes in hippocampal neuronal morphology and apoptosis, inhibited acetylcholinesterase (AChE) activity, increased the acetylcholine (ACh) content, and increased the protein and mRNA expression of brain-derived neurotrophic factor (BDNF) and phospho-cAMP response element-binding (p-CREB) compared with those in the model group (P < 0.05 & P < 0.01). These findings demonstrated that HAS attenuated scopolamine-induced cognitive impairments mainly by enhancing the activity of the cholinergic system and increasing the CREB/BDNF signalling pathway.

마우스에서 국내 육성 신품종 ‘신예감’ 추출물의 기억력 증진 효과

A new mandarin hybrid cultivar called ‘Shinyegam’ was developed from a cross between ‘Kiyomi’ (Citrus unshiu × C. sinensis) and ‘Wilking’ (Citrus reticulata) at the Citrus Research Institute of the National Institute of Horticultural and Herbal Science in 2012. The ‘Shinyegam’ was extracted with 70% ethanol (SYGE), and polyphenol content was measured to assess total antioxidant activity of flavonoids. Radical scavenging activities of the extracts were examined using a-a-diphenyl-β-picrylhydrazyl (DPPH), 2,2-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS), and ferric reducing antioxidant power (FRAP) assays. SYGE showed high polyphenol and flavonoid content as well as strong DPPH, ABTS, and FRAP radical scavenging activity. We used a mouse model to assess the memory enhancing properties of SYGE and its ameliorating activities on learning and memory impairments. Drug-induced amnesia was initiated by scopolamine treatment (2 mg/kg, interperitoneal). SYGE administration (25 mg/kg, oral) significantly enhanced cognitive function and attenuated scopolamine-induced cognitive impairments as determined by novel object recognition, passive avoidance and Y-maze tasks. In addition, SYGE increased brain-derived neurotrophic factor (BDNF) expression in the hippocampus. These results suggest that SYGE enhances learning and memory in normal states and attenuates memory loss caused by cholinergic dysfunction.

Preventive effect of N-stearoylethanolamine on memory disorders, blood and brain biochemical parameters in rats with experimental scopolamine-induced cognitive impairment

Preventive effect of N-stearoylethanolamine on memory disorders, blood and brain biochemical parameters in rats with experimental scopolamine-induced cognitive impairment

Schisanhenol improves learning and memory in scopolamine-treated mice by reducing acetylcholinesterase activity and attenuating oxidative damage through SIRT1-PGC-1α-Tau signaling pathway

Purpose: Schisanhenol is a compound derived from the fruit of a traditional Chinese herb Schisandra rubriflora. The aim of the present study was to evaluate the effect of Schisanhenol on the cognitive impairment induced by scopolamine.Material and Methods: Male mice were randomly divided into three Schisanhenol groups (10, 30, 100 mg/kg), Galantamine group (3 mg/kg), model group (1mg/kg scopolamine), and vehicle control group (normal saline). The learning and memory ability of mice was monitored by water morris maze. Hippocampus of mice were collected after behavioral testing and the activity of SOD, MDA, GSH-px, AChE were measured with standard biochemical procedures. Western blotting was used to analyze the expression of SIRT1, PGC-1α, phosphorylated Tau proteins.Results: Intraperitoneal administration of Schisanhenol (10, 30 or 100 mg/kg) significantly attenuated scopolamine-induced cognitive impairment in water morris maze. In addition, Schisanhenol increased the activity of SOD and GSH-px while decreased the content of AChE and MDA. Furthermore, western blotting analysis revealed that Schisanhenol increased the levels of SIRT1 and PGC-1α and decreased the level of phosphorylated Tau protein (Ser 396) significantly in the hippocampal tissues.Conclusions: Our findings indicated that Schisanhenol can attenuate scopolamine-induced learning impairment and enhance cognitive function, the mechanism via improve the cholinergic system and antioxidant ability, activate SIRT1-PGC1α signaling, inhibit the phosphorylation of Tau, and would be an effective candidate against cognitive disorders, such as Alzheimer's disease.

Diosmin is neuroprotective in a rat model of scopolamine-induced cognitive impairment.

Scopolamine, a muscarinic cholinergic receptor antagonist, is used as a standard pharmaceutical model for inducing cognitive impairment in animals. Several cognitive behaviors, such as motor function, anxiety, short-term memory, attention are affected by injections of scopolamine. In this study, we have assessed the effects of administration of the diosmin (DM, 50 and 100 mg/kg), before injection of 0.4 mg/kg of scopolamine on memory and motor function, the hippocampal dentate gyrus (DG) electrophysiological activity as well as brain inflammation. Eighty male rats were randomly divided into five groups (Control, Veh + scopolamine, DM (50) + scopolamine and DM (100) + scopolamine, donepezil (DP) + scopolamine, n = 16). Scopolamine (0.4 mg/kg, i.p.) is used, in order to induce an animal model of cognitive impairment. Rats pretreated with doses of 50 and 100 mg/kg of DM, 3 mg/kg of DP and/or normal saline for 7 days, before injection of scopolamine. Long-term potentiation (LTP) recording was done for electrophysiological activity assessment. Passive avoidance task (PAT), rotarod and spatial memory tests were evaluated, using a shuttle box, rotarod apparatus and Morris water maze (MWM), respectively. Results indicated that DM at doses of 50 and 100 mg/kg, significantly reversed the LTP (amplitude and slope) impairment of the hippocampal DG neurons, induced by scopolamine. Also, DM at doses of 50 and 100 mg/kg increased the percent of the total time that animals spent in goal quarter, the step-through latency (s) and bar latency time in an animal model of cognitive impairment (p < 0.01 and p < 0.001), respectively. The concentrations of TNF-α in hippocampus of the DM and donepezil groups was significantly lower than the Veh + scopolamine group (p < 0.01). This study revealed that the DM is effective in preventing the disruption of synaptic plasticity and cognitive impairments, induced by scopolamine. The positive effects of DM may be mediated through a decline in the TNF- α concentrations in hippocampus as a pro-inflammatory cytokine. Thus, the acquired results suggested that the DM can be used, as a useful and suitable agent for memory restoration, in the treatment of dementia, seen in elderlies.

Rational Design of Novel Selective Dual-Target Inhibitors of Acetylcholinesterase and Monoamine Oxidase B as Potential Anti-Alzheimer's Disease Agents.

Multifunctional agents aiming at cholinesterases (ChEs) and monoamine oxidases (MAOs) are promising therapy for Alzheimer's disease (AD). Herein, a series of novel propargylamine-modified pyrimidinylthiourea derivatives (1-4) were designed and synthesized as dual inhibitors of ChEs and MAOs with other functions against AD. Most of these derivatives inhibited ChEs and MAOs with IC50 values in the micro- or nanomolar ranges. Compound 1c displayed the dual functional profile of targeting the AChE (IC50 = 0.032 ± 0.007 μM) and MAO-B (IC50 = 2.117 ± 0.061 μM), along with the improved blood-brain barrier (BBB) permeability, antioxidant ability, and good copper chelating property in vitro. Animal studies showed that compound 1c·HCl could inhibit the cerebral AChE/MAO-B activities and alleviate scopolamine-induced cognitive impairment in mice. Combined with good oral bioavailability ( F = 45.55%), these findings demonstrated that compound 1c may be a potent brain permeable multifunctional candidate for the treatment of AD.

Moringa oleifera Seed Extract Alleviates Scopolamine-Induced Learning and Memory Impairment in Mice.

The extract of Moringa oleifera seeds has been shown to possess various pharmacological properties. In the present study, we assessed the neuropharmacological effects of 70% ethanolic M. oleifera seed extract (MSE) on cognitive impairment caused by scopolamine injection in mice using the passive avoidance and Morris water maze (MWM) tests. MSE (250 or 500 mg/kg) was administered to mice by oral gavage for 7 or 14 days, and cognitive impairment was induced by intraperitoneal injection of scopolamine (4 mg/kg) for 1 or 6 days. Mice that received scopolamine alone showed impaired learning and memory retention and considerably decreased cholinergic system reactivity and neurogenesis in the hippocampus. MSE pretreatment significantly ameliorated scopolamine-induced cognitive impairment and enhanced cholinergic system reactivity and neurogenesis in the hippocampus. Additionally, the protein expressions of phosphorylated Akt, ERK1/2, and CREB in the hippocampus were significantly decreased by scopolamine, but these decreases were reversed by MSE treatment. These results suggest that MSE-induced ameliorative cognitive effects are mediated by enhancement of the cholinergic neurotransmission system and neurogenesis via activation of the Akt, ERK1/2, and CREB signaling pathways. These findings suggest that MSE could be a potent neuropharmacological drug against amnesia, and its mechanism might be modulation of cholinergic activity via the Akt, ERK1/2, and CREB signaling pathways.