Scopolamine-induced Cognitive Impairment In Mice Research Articles

Prophylactic and therapeutic inhalation of two essential oils ameliorates scopolamine-induced cognitive impairment in mice

Clover and lemongrass essential oils of contrasting composition, at three concentration levels (1%, 5%, 10%), were administrated via prophylactic and therapeutic inhalation to scopolamine-treated mice. Chemical analysis showed that clover oil was dominant in eugenol (47.69%) and lemongrass free of eugenol but mainly containing monoterpenoids of comparable proportions. Animal behavioural and brain biochemical tests showed that injection of scopolamine caused memory and learning deficit in mice while prophylactic and therapeutic inhalation of two oils at moderate to high concentrations all obviously reversed the cognitive impairment via inhibiting acetylcholinesterase activities, oxidation and inflammation. Lemongrass essential oil with diverse monoterpenoids can be as effective as or a little bit more potent than eugenol-rich clover essential oil possibly due to the synergistic effect of various monoterpenoids. These findings implied that sniffing of such aroma recipes could be a promising complementary approach for the mitigation of Alzheimer’s disease-related cognitive impairment.

A novel neuroprotective peptide YVYAETY identified and screened from Flammulina velutipes protein hydrolysates attenuates scopolamine-induced cognitive impairment in mice.

Flammulina velutipes protein hydrolysates are known for their abundant amino acids and excellent developmental values. This study aimed to identify and screen neuroprotective peptides from F. velutipes protein hydrolysates in vitro and validate the protective effects of YVYAETY on memory impairment in scopolamine-induced mice. The F. velutipes protein was hydrolyzed by simulated gastrointestinal digestion, followed by purification through ultrafiltration and gel chromatography. The fraction exhibiting the strongest neuroprotective activity was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The main identified peptides (SDLKPADF, WNDHYY, YVYAETY, and WFHPLF) effectively mitigated excessive ROS production by increasing SOD and GSH-px activities while inhibiting cell apoptosis and mitochondrial membrane potential (MMP) collapse against oxidative stress in Aβ25-35-induced HT22 cells. By molecular docking, the interaction between peptides and the active site of the Keap1-Kelch domain reveals their capacity to regulate the Keap1/Nrf2/HO-1 pathway. In vitro, the peptide YVYAETY had the best effect and can be further validated in vivo. The behavioral tests showed that YVYAETY improved scopolamine-induced cognitive impairment in mice. YVYAETY also alleviated neuron damage including neuron vacuolation and pyknotic nuclei in the hippocampus. Furthermore, it significantly inhibited oxidative stress and suppressed the activation of the Nrf2 pathway. Therefore, this study revealed that YVYAETY had the potential to serve as a novel neuroprotective agent.

The Water Extract of Dendropanax morbiferus Ameliorates Scopolamine-Induced Cognitive Impairment in Mice

The Water Extract of Dendropanax morbiferus Ameliorates Scopolamine-Induced Cognitive Impairment in Mice

Neuroprotective Effect of Levetiracetam in Combination with Berberine on Scopolamine Induced-Cognitive Impairment in Mice: A Behavioral and Biochemical Approach

Background: Presently, only four drugs have been approved by FDA for Alzheimer’s disease (AD). A drug repurposing approach can be fruitful in searching for promising candidates for AD. Objective: The objective of the work was to evaluate the neuroprotective effect of levetiracetam (LEV) in combination with berberine (BER) in scopolamine-induced cognitive impairment in mice by applying a drug repositioning approach owing to their antioxidant potential. Methods: Cognitive impairment was induced in mice by scopolamine. Morris water maze, elevated plus maze, and Y-maze were used to evaluate behavioral parameters. Assays for acetylcholinesterase (AChE), reduced glutathione (GSH), malondialdehyde (MDA), catalase, nitrite, TNF-α, and brain histopathology were performed. Results: The transfer latency time and percentage of spontaneous alternation were significantly reduced and significant alterations in AChE and MDA levels, GSH concentration, and improvement in nitrite and catalase levels were also evidenced after the treatment of mice with a combination of LEV and BER in comparison to independent drugs, standard and disease control groups. The antioxidant defense was also improved and TNF-α levels were significantly reduced by a combination of LEV and BER. Improvement in neuronal damage by restoration of the cytoarchitecture of the brain was also seen in the histopathological study of the brain of treatment groups. Conclusion: The present study has demonstrated that the combination of LEV and BER has significantly improved cognition in mice by lipid peroxidation inhibition, augmentation of endogenous antioxidant enzymes, the decline in TNF- α levels, and AChE activity in the brain when compared to individual drugs, standard and disease control owing to their strong antioxidant and anti-inflammatory potentials.

Neuroprotective effects of novel pyrrolidine-2-one derivatives on scopolamine-induced cognitive impairment in mice: Behavioral and biochemical analysis

Alzheimer's disease (AD) is a long-term neurodegenerative condition that impairs cognitive abilities. In brain acetylcholine deficit and oxidative stress may be considered the key pathogenic causes for AD, even though the basic etiology is still unknown. The effects of some novel pyrrolidine-2-one derivatives on the learning and memory deficits caused by scopolamine in mice were examined in the current study. The learning and memory parameters were assessed using the morris water maze test, rota rod test the and locomotor activity. A number of biochemical factors were also evaluated, including acetylcholinesterase (AChE), lipid peroxidation (LPO), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CA), and nitrite oxide (NO) assay. The current study shows that these derivatives were more effective and comparable to donepezil at treating the behavioral and biochemical changes brought on by scopolamine. The observed results showed pyrrolidine-2-one derivatives as a promising candidate for diseases associated with cognitive deficits.

Ameliorative Effect of Medicarpin on Scopolamine-Induced Cognitive Impairment in Mice

The ameliorative effect of medicarpin (MC) was investigated by animal behavioral experiments such as Morris water maze (MWM), Y-maze, and passive avoidance test (PAT), using scopolamine-induced cognitively impaired mice. The scopolamine (5 mg/kg), donepezil (5 mg/kg), and MC (5 and 15 mg/kg) were administered by intraperitoneal injection at a volume of 0.3 mL. In the MWM, the escape latency times of MC-treated groups were significantly decreased compared with the scopolamine-treated negative control, and times spent in the platform zone of MC-treated groups were increased dose-dependently. In the Y-maze, the zone alternations of the MC-treated group were increased to the level of the donepezil-treated positive control. In the PAT, the crossing times of MC-treated groups were significantly higher than those of the negative control with dose-dependency. On the other hand, the monoamine oxidase (MAO)-A, MAO-B, and acetylcholinesterase (AChE) activities, relating to cognitive functions, in hippocampus treated with MC were decreased. In addition, the AChE activity in SH-SY5Y cells was significantly decreased. In Western blots, phosphorylated cyclic adenosine monophosphate (cAMP) response element-binding protein (p-CREB), brain-derived neurotrophic factor (BDNF), phosphorylated protein kinase B (p-Akt), and dopamine D2 receptor (D2R) levels in the hippocampus were higher than those of the negative control. In addition, p-CREB, BDNF, p-Akt, and D2R levels in SH-SY5Y cells treated with MC were significantly increased. These results showed that MC ameliorated a cognitive function along with increased BDNF and D2R expressions, and they suggested that MC could be used for the treatment of neurological disorders such as Alzheimer’s disease and Parkinson’s disease.

Anti-Alzheimer's and Antioxidant Activity of Ethanolic Seed Extract of Sapindus emarginatus Vahl on Scopolamine-Induced Cognitive Impairment in Mice

Background: Alzheimer's disease (AD) is a common nerve problem that leads to memory loss, particularly in the elderly. A shortage of acetylcholine in the brain, as well as oxidative stress, induces Alzheimer's disease. Currently, limited drugs are available to treat Alzheimer's disease because continuous use of these medications causes several side effects. Hence, we need high efficacious drugs to treat Alzheimer's disease with fewer side effects. Sapindus emarginatus Vahl or soap nut is a member of the Sapindaceae family. It's been used traditionally as an antiepileptic, antipruritic, antifertility, antiemetic, and anti-inflammatory agent. It is cheap, widely available, and reported to counteract chronic diseases linked to oxidative stress, such as ulcers and dyslipidemia. Objective: The purpose of this study was to determine the anti-Alzheimer and antioxidant properties of ethanolic seed extract of Sapindus emarginatus (ESSE) against scopolamine-induced amnesia. Methods: The total flavonoid level of the ESSE was estimated by a UV-visible spectrophotometer. The scopolamine (1 mg/kg/PO) was administered as a single intraperitoneal injection on the seventh day for induction of dementia in mice. The ESSE (250 and 500 mg/kg/PO) and donepezil (2.5 mg/kg/PO) was administered orally for 7 days. The neurobehavioral tests such as an elevated plus maze, radial arm maze, and Y-maze tests were undertaken for estimation of behavioral trials. The brain homogenate was used for the estimation of acetylcholine, acetylcholinesterase, and oxidative cell injury markers such as MDA, LH, SOD, CAT, and GSH. Results: The total flavonoid content of the extract was 0.47 mg of QE/g. Scopolamine degraded memory, as well as caused alterations in acetylcholine, acetylcholinesterase, and elevated oxidative stress in the brain. Pretreatment with ESSE reduced scopolamine-induced behavioral, neurochemical, and oxidative stress markers. Conclusion: The ESSE has an anti-amnesic impact, making it an attractive option for targeting multiple events as a possible technique to slow cognitive impairment.

Tilapia Head Protein Hydrolysate Attenuates Scopolamine-Induced Cognitive Impairment through the Gut-Brain Axis in Mice.

The destruction of the homeostasis in the gut-brain axis can lead to cognitive impairment and memory decline. Dietary intervention with bioactive peptides from aquatic products is an innovative strategy to prevent cognitive deficits. The present study aimed to determine the neuroprotective effect of tilapia head protein hydrolysate (THPH) on scopolamine-induced cognitive impairment in mice, and to further explore its mechanism through the microbiota–gut-brain axis. The results showed that THPH administration significantly improved the cognitive behavior of mice, and normalized the cholinergic system and oxidative stress system of the mice brain. The histopathological observation showed that THPH administration significantly reduced the pathological damage of hippocampal neurons, increased the number of mature neurons marked by NeuN and delayed the activation of astrocytes in the hippocampus of mice. In addition, THPH administration maintained the stability of cholinergic system, alleviated oxidative stress and further improved the cognitive impairment by reshaping the gut microbiota structure of scopolamine-induced mice and alleviating the disorder of lipid metabolism and amino acid metabolism in serum. In conclusion, our research shows that THPH supplementation is a nutritional strategy to alleviate cognitive impairment through the gut-brain axis.

Effect of Glycyrrhizic Acid on Scopolamine-Induced Cognitive Impairment in Mice.

PurposeCognitive impairment is one of the main symptoms of Alzheimer disease and other dementias. Glycyrrhiza uralensis is a natural product that has a protective effect against cognitive impairment. In this study, we investigated whether glycyrrhizic acid, among the main bioactive components of Glycyrrhiza uralensis, has a neuroprotective effect on scopolamine-induced cognitive impairment.MethodsTwenty-week-old male Institute of Cancer Research mice were used in this study. The scopolamine-induced cognitive impairment mice model was used. Glycyrrhizic acid was orally administered to mice once daily for 21 days, while scopolamine (1 mg/kg) treatment was delivered 30 minutes before behavioral tests. Donepezil (2 mg/kg) was used as a positive drug control. To evaluate the effect of glycyrrhizic acid, the following assessments were performed on hippocampal tissue: Y-maze test, acetylcholinesterase activity, antioxidant enzymes’ activity (superoxide dismutase, catalase). Western blotting for phosphor-extracellular signal-regulated kinase, P38, and c-Jun NH2-terminal kinase was conducted.ResultsWe found that glycyrrhizic acid administration significantly improved scopolamine-induced cognitive impairment in the Y-maze test. The acetylcholinesterase activity, superoxide dismutase, and catalase activity in the glycyrrhizic acid-treated group showed a significant reversal of cognitive impairment compared with the scopolamine-treated group.ConclusionsOur results suggest that glycyrrhizic acid has a neuroprotective effect on cognitive function in scopolamine-induced cognitive impairment.

Evaluation of neuroprotective and anti-amnesic effects of Elaeagnus umbellata Thunb. On scopolamine-induced memory impairment in mice

BackgroundElaeagnus umbellata is abundantly found in Himalayan regions of Pakistan which is traditionally used to treat various health disorders. However, the experimental evidence supporting the anti-amnesic effect is limited. Therefore the study was aimed to evaluate the prospective beneficial effect of E. umbellata on learning and memory in mice.ObjectivesTo assess neuroprotective and anti-amnesic effects of E. umbellata fruit extracts and isolated compounds on the central nervous system.MethodsMajor phytochemical groups present in methanolic extract of E. umbellata were qualitatively determined. The total phenolic and flavonoid contents were also determined in extract/fractions of E. umbellata. On the basis of in vitro promising anticholinesterases (AChE & BChE) and antioxidant activities observed for CHF. Ext and isolated compound-I (Chlorogenic acid = CGA), they were further evaluated for learning and memory in normal and scopolamine-induced cognitive impairment in mice using memory behavioral tests such as the Y maze and Novel object recognition using standard procedures. The test sample were further assessed for in vivo anticholinesterases (AChE & BChE) and DPPH free radical scavenging activities in mice brain sample and finally validated by molecular docking study using GOLD software.ResultsThe extract/fractions and isolated compounds were tested for their anticholinesterase and antioxidant potentials. The CHF. Ext and CGA showed maximum % inhibition of tested cholinesterases and free radicals. The CHF. Ext and CGA reversed the effects of scopolamine in mice. The CHF. Ext and CGA significantly increased the alternate arm returns and % spontaneous alteration performance while escape latency times (second) significantly decreased in Y maze test. The CHF. Ext and CGA significantly increased the time spent with novel object and also increased the discrimination index in the Novel object recognition test. Furthermore, molecular docking was used to validate the mechanism of cholinesterases inhibition of isolated compounds.ConclusionThe data obtained from behavioral and biochemical studies (AChE/BChE and DPPH/ABTS inhibition) have shown that E. umbellata possessed significant memory enhancing potency. These results suggest that E. umbellata extract possess potential antiamnesic effects and amongst the isolated compounds, compound I could be more effective anti-amnesic therapeutics. However, further studies are needed to identify the exact mechanism of action.Graphical abstract

Comparing Acetylcholinesterase and Butyrylcholinesterase Inhibition Effect of Total Extract and Fractions with Alcaloid-Rich Extract of Huperzia Serrata (Thunb.) Trevis.

Herbal extract, rich with natural compounds, has been used for medicinal purpose such as treating neurological disorders such as cognitive defection for a long period of time, often without significant adverse effects. We compared AChE and BuChE – inhibition effect of total extracts and fractions of Huperzia serrata (Thunb.) Trevis. with alcaloid-rich extract. Our samples were subjected under supersonic extraction with ethanol 50o as solvent and fractionally extracted with n-hexane, EtOAc and n-butanol, respectively; alcaloid-rich extract was collected simutaneously. Ellman’s method was used to assay AChE and BuChE inhibition activity. Results: Alcaloid-rich extraction proved to be the superior AChE inhibiting agent, its activity nearly 6 fold of the most active Huperzia serrata extraction with IC50 value of 7.93 (5.43-10.98) µg/ml. While the fractions as well as the total extract did not provide any BuChE inhibition activity, alcaloid-rich extract showed weak ability (IC50 at 76.67 (64.78 – 91.84) µg/ml). Overall, the superior enzyme inhibition effect of alcaloid-rich extract might open a new approach in preventing and treating neurological disorders such as alzheimer’s.
 Keywords
 Huperzia serrata (Thunb.) Trevis, alcaloid, Acetylcholinesrerase inhibitors (AChE); butyrylcholinesterase (BuChE), Alzheimer.
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Dracocephalum moldavica attenuates scopolamine-induced cognitive impairment through activation of hippocampal ERK-CREB signaling in mice

Ethnopharmacological relevanceDracocephalum moldavica (Moldavian balm) has been traditionally used for the treatment of intellectual disabilities, migraines and cardiovascular problems in East Asia. Recent scientific studies have demonstrated the usefulness of this plant to treat neurodegenerative disorders, including Alzheimer's disease. Aim of the studyThis study aimed to investigate the effects of the ethanolic extract of D. moldavica leaves (EEDM) on scopolamine-induced cognitive impairment in mice and the underlying mechanisms of action. Materials and methodsThe behavioral effects of EEDM were examined using the step-through passive avoidance and Morris water maze tasks. To elucidate the underlying mechanism, we tested whether EEDM affects acetylcholinesterase activity and the expression of memory-related signaling molecules including extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB) in the hippocampus. ResultsEEDM (25, 50 or 100 mg/kg) significantly ameliorated the scopolamine-induced step-through latency reduction in the passive avoidance task in mice. In the Morris water maze task, EEDM (50 mg/kg) significantly attenuated scopolamine-induced memory impairment. Furthermore, the administration of EEDM increased the phosphorylation levels of ERK and CREB in the hippocampus but did not alter acetylcholinesterase activity. ConclusionsThese findings suggest that EEDM significantly attenuates scopolamine-induced memory impairment in mice and may be a promising therapeutic agent for improving memory impairment.

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.

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.

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.

Novel Tadalafil Derivatives Ameliorates Scopolamine-Induced Cognitive Impairment in Mice via Inhibition of Acetylcholinesterase (AChE) and Phosphodiesterase 5 (PDE5).

On the basis of the drug-repositioning and redeveloping strategy, first-generation dual-target inhibitors of acetylcholinesterase (AChE) and phosphodiesterase 5 (PDE5) have been recently reported as a potentially novel therapeutic method for the treatment of Alzheimer's disease (AD), and the lead compound 2 has proven this method was feasible in AD mouse models. In this study, our work focused on exploring alternative novel tadalafil derivatives (3a-s). Among the 19 analogues, compound 3c exhibited good selective dual-target AChE/PDE5 inhibition and good blood-brain barrier (BBB) permeability. Moreover, its citrate (3c·Cit) possessed improved water solubility and good effects against scopolamine-induced cognitive impairment with inhibition of cortical AChE activities and enhancement of cAMP response element-binding protein (CREB) phosphorylation ex vivo.

Lee, J.E. et al. Ethanol Extract of Oldenlandia diffusa Herba Attenuates Scopolamine-Induced Cognitive Impairments in Mice via Activation of BDNF, P-CREB and Inhibition of Acetylcholinesterase.

The authors wish to make the following corrections to this paper [1].[...].

Ethanol Extract of Oldenlandia diffusa Herba Attenuates Scopolamine-Induced Cognitive Impairments in Mice via Activation of BDNF, P-CREB and Inhibition of Acetylcholinesterase.

Though Oldenlandia diffusa Herba (ODH) has been known to exhibit anti-cancer and anti-inflammatory effects, its anti-amnestic effect has never been reported so far. The aim of this present study was to elucidate the anti-amnestic effect of ODH. ODH pretreatment significantly reduced escape latency of scopolamine treated Institute of Cancer Research (ICR) mice compared to untreated control groups in a Morris water maze test. Similarly, the passive avoidance test showed that ODH treatment recovered the scopolamine induced amnesia in the ICR mouse model. Concentration of Ach in brains of ODH treated mice was increased compared to that of scopolamine treated mice. In addition, activity of acetylcholinesterase (AChE) was notably decreased by ODH. The protein expression of brain-derived neurotrophic factor (BDNF) and phospho-cAMP response element-binding protein (p-CREB) (Ser133) was increased in ODH pretreated group compared to control group. Consistently, immunohistochemistry (IHC) revealed the elevated expression of brain-derived neurotrophic factor (BDNF) and p-CREB in brains of ODH treated mice compared to the control group. Overall, these findings suggest that ODH has anti-amnestic potential via activation of BDNF and p-CREB and inhibition of AChE in mice with scopolamine induced amnesia.

Discovery of novel propargylamine-modified 4-aminoalkyl imidazole substituted pyrimidinylthiourea derivatives as multifunctional agents for the treatment of Alzheimer's disease

A series of novel propargylamine-modified pyrimidinylthiourea derivatives (1–3) were designed and synthesized as multifunctional agents for Alzheimer's disease (AD) therapy, and their potential was evaluated through various biological experiments. Among these derivatives, compound 1b displayed good selective inhibitory activity against AChE (vs BuChE, IC50 = 0.324 μM, SI > 123) and MAO-B (vs MAO-A, IC50 = 1.427 μM, SI > 35). Molecular docking study showed that the pyrimidinylthiourea moiety of 1b could bind to the catalytic active site (CAS) of AChE, and the propargylamine moiety interacted directly with the flavin adenine dinucleotide (FAD) of MAO-B. Moreover, 1b demonstrated mild antioxidant ability, good copper chelating property, effective inhibitory activity against Cu2+-induced Aβ1−42 aggregation, moderate neuroprotection, low cytotoxicity, and appropriate blood−brain barrier (BBB) permeability in vitro and was capable of ameliorating scopolamine-induced cognitive impairment in mice. These results indicated that 1b has the potential to be a multifunctional candidate for the treatment of Alzheimer's disease.

Neuroprotective and Antiamnesic Effects of Mitragyna inermis Willd (Rubiaceae) on Scopolamine-Induced Memory Impairment in Mice.

Aim. To assess memory improvement and neuroprotective and antioxidant effects of Mitragyna inermis (M. inermis) leaf decoction on the central nervous system. Methodology. Leaf decoction of M. inermis was tested on learning and memory in normal and scopolamine-induced cognitive impairment in mice using memory behavioral tests such as the Morris water maze, object recognition task, and elevated plus maze. Oxidative stress enzymes—catalase, superoxide dismutase, and the thiobarbituric acid reactive substance, a product of lipid peroxidation—were quantified. In each test, mice 18 to 25 g were divided into groups of 5. Results. The extract reversed the effects of scopolamine in mice. The extract significantly increased discrimination index in the object recognition task test and inflexion ratio in the elevated plus maze test. The times spent in target quadrant in MWM increased while the transfer latency decreased in mice treated by M. inermis at the dose of 196.5 mg/kg. The activity levels of superoxide dismutase and catalase were significantly increased, whereas the thiobarbituric acid reactive substance was significantly decreased after 8 consecutive days of treatment with M. inermis at the dose of 393 mg/kg. Conclusion. These results suggest that M. inermis leaf extract possess potential antiamnesic effects.