Effect of wild ginseng on scopolamine-induced acetylcholine depletion in the rat hippocampus

Neuroprotective Effect of Thiazolidine-2,4-dione Derivatives on Memory Deficits and Neuropathological Symptoms of Dementia on a Scopolamine-Induced Alzheimer's Model in Adult Male Wistar Rats

Alzheimer's disease (AD) is a neurodegenerative disorder associated with a decline in memory deficits and neuropathological diagnosis with loss of cholinergic neurons in the brains of older adults. Based on these facts and an increasing number of involved people worldwide, this investigation aimed to study the improvement of memory and cognitive impairments via an anticholinergic approach of thiazolidine-2,4-diones (TZDs) in the scopolamine-induced model of Alzheimer type in adult male Wistar rats (n = 40). The results indicated data analysis obtained from in vivo and in vitro tests for (E)-5-(3-hydroxybenzylidene)-3-(2-oxo-2-phenylethyl)thiazolidine-2,4-dione (TZ3O) (2 and 4 mg/kg) with the meta-hydroxy group and (E)-5-(4-methoxybenzylidene)-3-(2-oxo-2-phenylethyl)thiazolidine-2,4-dione (TZ4M) (2 and 3 mg/kg) with the para-methoxy group showed a neuroprotective effect. TZ3O and TZ4M alleviated the scopolamine-induced cognitive decline of the Alzheimer model in adult male Wistar rats. These initial and noteworthy results could be assumed as a starting point for the evolution of new anti-Alzheimer agents.

Neuroprotective role of medicinal plant extracts evaluated in a scopolamine-induced rat model of Alzheimer's disease

BackgroundAlzheimer's disease is a debilitating neurological brain disease with memory impairment among the first signs. Scopolamine (SCO), a muscarinic receptor antagonist that disrupts cognition and memory acquisition, is considered a psychopharmacological AD model. We investigate the effectiveness of medicinal plants in mitigating the SCO-induced neurobehavioural damage in rats.Materials and MethodsAnimals were injected with Scopolamine hydrobromide trihydrate (2.2 mg/kg IP.) daily for 2 months. Each treatment group was administered one of four medicinal spice extracts (Nigella sativa, 400 mg/kg; rosemary, 200 mg/kg; sage, 600 mg/kg and ginseng;200 mg/kg 90 minutes after SCO injection. Animals were subjected to cognitive-behavioral tests (NOR, Y-maze, and MWM). After the experiment, we extracted the brains for histopathological examination and biochemical assessment for oxidative stress (levels of TT, CAT and TBARS) and gene expression of acetylcholinesterase and brain monoamines.ResultsAs expected, SCO treatment impaired memory and cognition, increased oxidative stress, decreased neurotransmitters, and caused severe neurodegenerative changes in the brain.ConclusionSurprisingly, these effects were measurably moderated by the administration of all four plant extracts, indicating a neuroprotective action that we suggest could alleviate AD disease manifestations.

Ginseng® Alleviates Malathion-Induced Hepatorenal Injury through Modulation of the Biochemical, Antioxidant, Anti-Apoptotic, and Anti-Inflammatory Markers in Male Rats

This study aims to see if Ginseng^® can reduce the hepatorenal damage caused by malathion. Four groups of forty male Wistar albino rats were alienated. Group 1 was a control group that got orally supplied corn oil (vehicle). Group 2 was intoxicated by malathion dissolved in corn oil orally at 135 mg/kg/day. Group 3 orally received both malathion + Panax Ginseng^® (300 mg/kg/day). Group 4 was orally given Panax Ginseng^® at a 300 mg/kg/day dose. Treatments were administered daily and continued for up to 30 consecutive days. Malathion's toxic effect on both hepatic and renal tissues was revealed by a considerable loss in body weight and biochemically by a marked increase in liver enzymes, LDH, ACP, cholesterol, and functional renal markers with a marked decrease in serum TP, albumin, and TG levels with decreased AchE and Paraoxonase activity. Additionally, malondialdehydes, nitric oxide (nitrite), 8-hydroxy-2-deoxyguanosine, and TNFα with a significant drop in the antioxidant activities were reported in the malathion group. Malathion upregulated the inflammatory cytokines and apoptotic genes, while Nrf2, Bcl2, and HO-1 were downregulated. Ginseng^® and malathion co-treatment reduced malathion's harmful effects by restoring metabolic indicators, enhancing antioxidant pursuit, lowering the inflammatory reaction, and alleviating pathological alterations. So, Ginseng^® may have protective effects against hepatic and renal malathion-induced toxicity on biochemical, antioxidant, molecular, and cell levels.

Neuroprotective effects of quercetin produced by an endophytic fungus Nigrospora oryzae isolated from Tinospora cordifolia

AIMS

Alzheimer's disease is considered one of the most prevalent neurodegenerative disorders and dementia is the core symptom of this disease. This study was aimed to test the bioactive compounds produced by endophytic fungus for the inhibition of acetylcholinesterase (AChE) activity and to identify the compound responsible for this activity.

METHODS AND RESULTS

Endophytic fungi were isolated from the medicinal plant Tinospora cordifolia and screened for AChE inhibition and antioxidant activity. The extract of one of the isolates Nigrospora oryzae (GL15) showed maximum AChE inhibition as well as antioxidant activity. The compound responsible for AChE inhibition (fraction 3) was identified as quercetin based on UV, FTIR spectra, HPLC and ESI-MS analyses. Furthermore, the identification of quercetin in the extract of fraction 3 was confirmed by ¹ H NMR analysis. This extract showed anti-dementia-like activity in scopolamine (SCO) model. The minimal effective dose of the extract of fraction 3 modulated the SCO-provoked cognitive deficits such as impairments in spatial recognition memory and latency period in Y-maze test and passive avoidance test, respectively. The SCO-induced modulation in cholinergic pathway was ameliorated by the extract of N. oryzae in hippocampus, resulting in decrease in AChE activity and restoration of cytoarchitecture of hippocampus.

CONCLUSIONS

The bioactive compound quercetin produced by N. oryzae may cure the learning and memory shortfalls via AChE-mediated mechanism in experimental mice.

SIGNIFICANCE AND IMPACT OF THE STUDY

The endophytic fungus N. oryzae serves as a potential source for the bioactive compound quercetin, which plays an important role in the management of Alzheimer's disease.

Maillard Reaction Products and Phenolic Compounds from Roasted Peanut Flour Extracts Prevent Scopolamine-Induced Amnesia Via Cholinergic Modulation and Antioxidative Effects in Mice

Research on the beneficial effects of Maillard reaction products (MRPs) and phenolic compounds derived from roasted peanut flour on the nervous system remains insufficient. This study aimed to evaluate the effect of a 28-day oral administration of defatted peanut extract rich in MPRs and polyphenolic compounds on the cognitive impairments and oxidative injury induced by scopolamine in a mouse model. Light and dark extracts from peanut flour were prepared by heating peanuts at 187°C for two different times (8.6 and 12.7 min) and defatted using soxhlet apparatus. The mice were orally pretreated with either roasted defatted peanuts extracts (100 mg/kg) or donepezil (3 mg/kg) for 21 days. On day 19 and until day 28, mice were injected subcutaneously with water or scopolamine (1 mg/kg body weight) 15 min after roasted defatted peanuts extracts/water feeding. Mice were subsequently subjected to a battery of behavioral tests including open field locomotor activity assay, and Morris water maze test. Brain tissues were collected to measure acetylcholine, acetylcholinesterase, and oxidative parameters (glutathione and malondialdehyde). Roasted defatted peanuts (light and dark) (100 mg/kg) treatment significantly ameliorated cognitive performance and reversed the oxidative damage when compared with the scopolamine group. These data demonstrate the defatted peanuts extracts exert potent anti-amnesic effects via the modulation of cholinergic and antioxidant activities.

Potency of Selected Berries, Grapes, and Citrus Fruit as Neuroprotective Agents

A healthy diet should nourish the brain with essential nutrients, including bioactive compounds, for normal brain functioning and to protect it from the negative effects of inflammation and oxidative stress. In this review, a concise summation of the protective effects of selected fruits, namely, berries, grapes, and citrus fruits, against neurological disorder is presented. The focus is on the neuroprotective potential of these fruits against neurodegenerative and mental disorders. The fruits selection was based on the vast reported pharmacological studies on their neuroprotection efficacies. Hence, the respective knowledge and limitations are discussed based on the biological and pharmacological evidence compiled from the previously reported laboratory, epidemiology, and intervention trials.

Constitutive and Stress-Induced Psychomotor Cortical Responses to Compound K Supplementation

Isolated ginsenoside metabolites such as Compound K (CK) are of increasing interest to consumer and clinical populations as safe and non-pharmacological means to enhance psychomotor performance constitutively and in response to physical or cognitive stress. Nevertheless, the influence of CK on behavioral performance and EEG measures of cortical activity in humans is undetermined. In this double-blinded, placebo-controlled, counterbalanced within-group study, dose-dependent responses to CK (placebo, 160 and 960 mg) were assessed after 2 weeks of supplementation in nineteen healthy men and women (age: 39.9 ± 7.9 year, height 170.2 ± 8.6 cm, weight 79.7 ± 11.9 kg). Performance on upper- and lower-body choice reaction tests (CRTs) was tested before and after intense lower-body anaerobic exercise. Treatment- and stress-related changes in brain activity were measured with high-density EEG based on event-related potentials, oscillations, and source activity. Upper- (−12.3 ± 3.5 ms, p = 0.002) and lower-body (−12.3 ± 4.9 ms, p = 0.021) response times improved after exercise, with no difference between treatments (upper: p = 0.354; lower: p = 0.926). Analysis of cortical activity in sensor and source space revealed global increases in cortical arousal after exercise. CK increased activity in cortical regions responsible for sustained attention and mitigated exercise-induced increases in arousal. Responses to exercise varied depending on task, but CK appeared to reduce sensory interference from lower-body exercise during an upper-body CRT and improve the general maintenance of task-relevant sensory processes.

Elaeagnus glabra f. oxyphylla Attenuates Scopolamine-Induced Learning and Memory Impairments in Mice by Improving Cholinergic Transmission via Activation of CREB/NGF Signaling

We aimed to investigate the therapeutic effects of an Elaeagnus glabra f. oxyphylla (EGFO) ethanol extract in mice with scopolamine-induced memory dysfunction. Fifty male mice were randomly divided into a normal control group, a scopolamine-treated group, a scopolamine and EGFO extract-treated group, and a scopolamine and tacrine-treated group. EGFO (50 or 100 mg/kg/day) was received for 21 days. Step-through passive avoidance and Y-maze tests were performed to examine the effects of treatment on learning and memory impairments. Acetylcholine (Ach) levels and acetylcholinesterase (AchE) activity were measured via an enzyme-linked immunosorbent assay (ELISA). Levels of choline acetyltransferase (ChAT), nerve growth factor (NGF), cAMP response element-binding protein (CREB), and apoptosis-related protein expression were determined via Western blot analysis. EGFO pretreatment significantly attenuated scopolamine-induced memory impairments, relative to findings observed in the scopolamine-treated group. Levels of cholinergic factors in the brain tissues were markedly attenuated in the scopolamine-treated group. EGFO treatment also attenuated neural apoptosis in scopolamine-treated mice by decreasing the expression of apoptosis-related proteins such as Bax, Bcl2, cleaved caspase-3, and TUNEL staining. These results suggest that EGFO improves memory and cognition in a mouse model of memory impairment by restoring cholinergic and anti-apoptotic activity, possibly via activation of CREB/NGF signaling.

Medicinal plants with acetylcholinesterase inhibitory activity

Alzheimer's disease, a progressive neurodegenerative disease, is characterised by hypofunction of acetylcholine (ACh) neurotransmitter in the distinct region of brain. Acetylcholinesterase (AChE) is an enzyme that metabolises the ACh at synaptic cleft resulting in Alzheimer's disease. Medicinal plants have been used to treat numerous ailments and improve human health from ancient time. A traditional system of medicine is long recognised for its effective management of neurological disorders. The present review confers the scope of some common medicinal plants with a special focus on AChE-mediated central nervous system complications especially Alzheimer's disease. Literature suggests that medicinal plants reduce neuronal dysfunctions by reducing AChE activity in different brain regions. In some instances, activation of AChE activity by medicinal plants also showed therapeutic potential. In conclusion, medicinal plants have a wide scope and possess therapeutic potential to efficiently manage neurological disorders associated with AChE dysregulation.

Jiao-Tai-Wan Improves Cognitive Dysfunctions through Cholinergic Pathway in Scopolamine-Treated Mice

Cognitive dysfunction is characterized as the gradual loss of learning ability and cognitive function, as well as memory impairment. Jiao-tai-wan (JTW), a Chinese medicine prescription including Coptis chinensis and cinnamon, is mainly used for the treatment of insomnia, while the effect of JTW in improving cognitive function has not been reported. In this study, we employed a scopolamine- (SCOP-) treated learning and memory deficit model to explore whether JTW could alleviate cognitive dysfunction. In behavioral experiments, Morris water maze, Y-maze, fearing condition test, and novel object discrimination test were conducted. Results showed that oral administration of JTW (2.1 g/kg, 4.2 g/kg, and 8.4 g/kg) can effectively promote the ability of spatial recognition, learning and memory, and the memory ability of fresh things of SCOP-treated mice. In addition, the activity of acetylcholinesterase (AChE) was effectively decreased; the activity of choline acetyltransferase (ChAT) and concentration of acetylcholine (Ach) were improved after JTW treatment in both hippocampus and cortex of SCOP-treated mice. JTW effectively ameliorated oxidative stress because of decreased the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) and increased the activities of superoxide dismutase (SOD) and catalase (CAT) in hippocampus and cortex. Furthermore, JTW promotes the expressions of neurotrophic factors including postsynaptic density protein 95 (PSD95) and synaptophysin (SYN) and brain-derived neurotrophic factor (BDNF) in both hippocampus and cortex. Nissl's staining shows that the neuroprotective effect of JTW was very effective. To sum up, JTW might be a promising candidate for the treatment of cognitive dysfunction.

Terminalia chebula extract prevents scopolamine-induced amnesia via cholinergic modulation and anti-oxidative effects in mice

BACKGROUND

Terminalia chebula Retz. (Combretaceae) is a traditional herbal medicine that is widely used in the treatment of diabetes, immunodeficiency diseases, and stomach ulcer in Asia. However, the anti-amnesic effect of T. chebula has not yet been investigated. The present study was designed to determine whether T. chebula extract (TCE) alleviates amnesia induced by scopolamine in mice. We also investigated possible mechanisms associated with cholinergic system and anti-oxidant effects.

METHODS

TCE (100 or 200 mg/kg) was orally administered to mice for fourteen days (days 1-14), and scopolamine was intraperitoneally injected to induce memory impairment for seven days (days 8-14). Learning and memory status were evaluated using the Morris water maze. Hippocampal levels of acetylcholine (ACh), acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) were measured ex vivo. Levels of reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA) in the hippocampus were also examined.

RESULTS

In the Morris water maze task, TCE treatment reversed scopolamine-induced learning and memory deficits in acquisition and retention. TCE reduced hippocampal AChE activities and increased ChAT and ACh levels in the scopolamine-induced model. Moreover, TCE treatment suppressed scopolamine-induced oxidative damage by ameliorating the increased levels of ROS, NO, and MDA.

CONCLUSION

These findings suggest that TCE exerts potent anti-amnesic effects via cholinergic modulation and anti-oxidant activity, thus providing evidence for its potential as a cognitive enhancer for amnesia.

Botanicals as Modulators of Neuroplasticity: Focus on BDNF

The involvement of brain-derived neurotrophic factor (BDNF) in different central nervous system (CNS) diseases suggests that this neurotrophin may represent an interesting and reliable therapeutic target. Accordingly, the search for new compounds, also from natural sources, able to modulate BDNF has been increasingly explored. The present review considers the literature on the effects of botanicals on BDNF. Botanicals considered were Bacopa monnieri (L.) Pennell, Coffea arabica L., Crocus sativus L., Eleutherococcus senticosus Maxim., Camellia sinensis (L.) Kuntze (green tea), Ginkgo biloba L., Hypericum perforatum L., Olea europaea L. (olive oil), Panax ginseng C.A. Meyer, Rhodiola rosea L., Salvia miltiorrhiza Bunge, Vitis vinifera L., Withania somnifera (L.) Dunal, and Perilla frutescens (L.) Britton. The effect of the active principles responsible for the efficacy of the extracts is reviewed and discussed as well. The high number of articles published (more than one hundred manuscripts for 14 botanicals) supports the growing interest in the use of natural products as BDNF modulators. The studies reported strengthen the hypothesis that botanicals may be considered useful modulators of BDNF in CNS diseases, without high side effects. Further clinical studies are mandatory to confirm botanicals as preventive agents or as useful adjuvant to the pharmacological treatment.

Neuroprotective effect of ipriflavone against scopolamine-induced memory impairment in rats

BACKGROUND

Alzheimer's disease is an age-related neurodegenerative disorder characterized clinically by a progressive loss of memory and cognitive functions resulting in severe dementia. Ipriflavone (IPRI) is a non-hormonal, semi-synthetic isoflavone, clinically used in some countries for the treatment and prevention of postmenopausal osteoporosis. Moreover, ipriflavone is a non-peptidomimetic small molecule AChE inhibitor with an improved bioavailability after systemic administration, due to its efficient blood-brain barrier permeability in comparison with peptidomimetic inhibitors.

OBJECTIVE

The present study aimed to evaluate the possible enhancing effects of IPRI on memory impairments caused by scopolamine administration.

METHODS

Male rats were administered IPRI (50 mg/kg, oral) 2 h before scopolamine injection (2 mg/kg, intraperitoneally injected) daily for 4 weeks. Effects of IPRI on acetylcholinesterase activity, amyloid-β precursor processing, and neuroplasticity in the rats' hippocampus were investigated.

RESULTS

Daily administration of IPRI reverted memory impairment caused by scopolamine as measured by the reduction of the escape latency. IPRI significantly alleviated the oxidative stress and restored the mRNA expression of both cAMP-response element-binding protein and brain-derived neurotrophic factor in the hippocampus. Furthermore, it significantly increased the expression of ADAM10 and ADAM17 (two putative α-secretase enzymes) and phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) that associated with decreased expression of β-secretase (BACE) in the hippocampus. Finally, both the amyloid-β (Aβ) and Tau pathologies were reduced.

CONCLUSIONS

IPRI showed promising neuroprotective effects against scopolamine-induced memory dysfunction in rats. These findings contributed to the stimulation of α-secretase enzymes, the activation of MAPK/ERK1/2, and the alleviation of oxidative stress.

Rg3-enriched ginseng extract ameliorates scopolamine-induced learning deficits in mice

Background

Ginseng (Panax ginseng C.A. Meyer) has been used as a traditional herb in the treatment of many medical disorders. Ginsenosides, which are triterpene derivatives that contain sugar moieties, are the main pharmacological ingredients in ginseng. This study was designed to investigate the effect of ginsenoside Rg3-enriched ginseng extract (Rg3GE) on scopolamine-induced memory impairment in mice.

Methods

Rg3GE (50 and 100 mg/kg) were administered to C57BL/6 mice by oral gavage for 14 days (days 1–14). Memory impairment was induced by scopolamine (1 mg/kg, intraperitoneal injection) for 6 days (days 914). The Morris water maze test was used to assess hippocampus-dependent spatial memory. The effects of scopolamine with or without Rg3GE on acetylcholinesterase and nuclear factor-κB (NF-κB) in the hippocampus were also examined.

Results

Mice with scopolamine treatment alone showed impairments in the acquisition and retention of spatial memory. Mice that received Rg3GE and scopolamine showed no scopolamine-induced impairment in the acquisition of spatial memory. Oral administration of Rg3GE suppressed the scopolamine-mediated increase in acetylcholinesterase activity and stimulation of the NF-κB pathway (i.e., phosphorylation of p65) in the hippocampus.

Conclusion

These findings suggest that Rg3GE may stabilize scopolamine-induced memory deficits through the inhibition of acetylcholinesterase activity and NF-κB signaling in the hippocampus.

Ginsenoside rg3 alleviates lipopolysaccharide-induced learning and memory impairments by anti-inflammatory activity in rats

The purpose of this study was to examine whether ginsenoside Rg3 (GRg3) could improve learning and memory impairments and inflammatory reactions induced by injecting lipopolysaccharide (LPS) into the brains of rats. The effects of GRg3 on proinflammatory mediators in the hippocampus and the underlying mechanisms of these effects were also investigated. Injection of LPS into the lateral ventricle caused chronic inflammation and produced deficits in learning in a memory-impairment animal model. Daily administration of GRg3 (10, 20, and 50 mg/kg, i.p.) for 21 consecutive days markedly improved the LPS-induced learning and memory disabilities demonstrated on the step-through passive avoidance test and Morris water maze test. GRg3 administration significantly decreased expression of pro-inflammatory mediators such as tumor necrosis factor-α, interleukin-1β, and cyclooxygenase-2 in the hippocampus, as assessed by reverse transcription-polymerase chain reaction analysis and immunohistochemistry. Together, these findings suggest that GRg3 significantly attenuated LPS-induced cognitive impairment by inhibiting the expression of pro-inflammatory mediators in the rat brain. These results suggest that GRg3 may be effective for preventing or slowing the development of neurological disorders, including Alzheimer's disease, by improving cognitive and memory functions due to its anti-inflammatory activity in the brain.

Modulation of nitrergic signalling pathway by American ginseng attenuates chronic unpredictable stress-induced cognitive impairment, neuroinflammation, and biochemical alterations

Prolonged stress causes extensive loss of neurons leading to deficits in cognitive performance. Increasing evidence indicates that accumulation of intercellular messenger, nitric oxide (NO), plays a crucial role in the pathogenesis of memory disorders. American ginseng (AG) is known to show protection in different animal models of neurological diseases; however, its exact mechanism of action is not clearly understood. Therefore, the current study was designed to investigate the interaction of AG against chronic unpredictable stress (CUS)-associated behavioral and biochemical alterations and the probable role of nitrergic pathway in this effect. Male Laca mice were exposed to a series of stressors along with drug/vehicle treatment daily for 28 days. CUS paradigm caused significant impairment in both acquisition and retention memory as measured in Morris water maze and elevated plus maze task. This was coupled with alterations in oxidative stress markers, mitochondrial enzyme complex activities, pro-inflammatory cytokine (TNF-α), and acetylcholinesterase levels in the hippocampus as compared with naïve group. Besides, there was a marked increase in serum corticosterone levels. AG (100, 200 mg/kg; p.o.) treatment significantly improved cognitive impairment; reduced TNF-α, acetylcholinesterase, and corticosterone levels; and attenuated oxidative-nitrergic stress. Furthermore, pre-treatment of L-arginine (100 mg/kg; i.p.), a nitric oxide donor, with subeffective dose of AG (100 mg/kg; p.o.) reversed its protective effects. However, L-NAME (10 mg/kg, i.p.), a non-specific NO synthase inhibitor, potentiated the effects of AG. Our findings suggest that modulation of nitrergic signalling cascade is involved in the protective effects of AG against CUS-induced cognitive dysfunction, oxidative stress, and neuroinflammation.

Actoprotective effect of ginseng: improving mental and physical performance

Actoprotectors are preparations that increase the mental performance and enhance body stability against physical loads without increasing oxygen consumption. Actoprotectors are regarded as a subclass of adaptogens that hold a significant capacity to increase physical performance. The focus of this article is studying adaptogen herbs of genus Panax (P. ginseng in particular) and their capabilities as actoprotectors. Some animal experiments and human studies about actoprotective properties of genus Panax attest that P. ginseng (administered as an extract) significantly increased the physical and intellectual work capacities, and the data provided suggests that ginseng is a natural source of actoprotectors. Preparations of ginseng can be regarded as potential actoprotectors which give way to further research of its influence on physical and mental work capacity, endurance and restoration after exhaustive physical loads while compared with reference actoprotectors.

The potent effects of ginseng root extract and memantine on cognitive dysfunction in male albino rats

The study determined the maximum intraperitoneal (ip) scopolamine dose inducing memory impairment in rats (2 mg/kg) compared to 0.5 or 1 mg/kg dose. The effect reflected by significant increase from normal in the latency time required for rats to find the hidden platform in water maze task and acetylcholinesterase (AChE) activities in cortex, hippocampus and striatum. The dose-related histopathological effect via the hemorrhage, vacuolation and gliosis in cortex and hippocampus is assessed. Then the study investigated the potency of Panax ginseng root extract on scopolamine cognitive dysfunction rat model compared to memantine hydrochloride as reference Food and Drug Administration approved. Ginseng extract was administered at dose 100 or 200 mg/kg/day and memantine at 20 mg/kg/day orally for 2 weeks. All treatments showed improvement in the water maze task, however, ginseng (200 mg/kg) group acquired the advantage without statistical difference control. Scopolamine (2 mg/kg ip) group showed significant increase in AChE reactivity and glutamate level and reduced monoamines (norepinephrine, dopamine and serotonin) and γ-aminobutyric acid contents in cortex, hippocampus and striatum. Ginseng extract in a dose-dependent manner appears effective as memantine and can improve memory impairment through the retrieved homeostasis via neurotransmitter levels and AChE activities in rat brain areas with partial effect on the histological feature of the brain tissue.

Protective effects of Ginkgo biloba extract (EGB 761) on astrocytes of rat hippocampus after exposure with scopolamine

The regular extract of Ginkgo biloba has been shown to possess neuroprotective properties in disorders like hypoxia, ischemia, seizure activity and peripheral nerve damage. Also, G. biloba has received attention as a potential cognitive enhancer for the treatment of Alzheimer's disease, but there is not any documentation about the effect of an extract of G. biloba on astrocytes. Therefore, the aim of this study was examined the effects of G. biloba extract on the rat's hippocampal astrocytes after scopolamine based amnesia. In this study, 36 adult male Wistar rats were used. Rats were randomly distributed into control, sham, protective and treatment groups. The rats in the sham group only received scopolamine hydrobromide (3 mg/kg) intraperitoneally. The rats in the protective and treatment groups received G. biloba extract (40, 80 mg/kg) for 7 days intraperitoneally before and after scopolamine injection. Forty eight hours after the last injection, the brains of the rats were withdrawn and fixed with paraformaldehide, and then after histological processing, the slices were stained with phosphotungstic acid-haematoxylin for astrocytes. Data were analyzed by the analysis of variance (ANOVA) post hoc Tukey test; P<0.05 was considered significant. Results showed that scopolamine can reduce the number of astrocytes in all areas of hippocampal formation compared with the control. However, G. biloba extract can compensate for the reduction in the number of astrocytes in the hippocampus before or after the encounter with scopolamine. We concluded that a pretreatment and treatment injection of G. biloba extract can have a protective effect for astrocytes in all areas of hippocampal formation.

Phellodendron amurense and Its Major Alkaloid Compound, Berberine Ameliorates Scopolamine-Induced Neuronal Impairment and Memory Dysfunction in Rats

We examine whether Phellodendron amurense (PA) and its major alkaloid compound, berberine (BER), improved memory defects caused by administering scopolamine in rats. Effects of PA and BER on the acetylcholinergic system and pro-inflammatory cytokines in the hippocampus were also investigated. Male rats were administered daily doses for 14 days of PA (100 and 200 mg/kg, i.p.) and BER (20 mg/kg, i.p.) 30 min before scopolamine injection (2 mg/kg, i.p.). Daily administration of PA and BER improved memory impairment as measured by the passive avoidance test and reduced the escape latency for finding the platform in the Morris water maze test. Administration of PA and BER significantly alleviated memory-associated decreases in cholinergic immunoreactivity and restored brain-derived neurotrophic factor and cAMP-response element-binding protein mRNA expression in the hippocampus. PA and BER also decreased significantly the expression of proinflammatory cytokines such as interleukin-1β, tumor necrosis factor-α and cyclooxygenase-2 mRNA in the hippocampus. These results demonstrated that PA and BER had significant neuroprotective effects against neuronal impairment and memory dysfunction caused by scopolamine in rats. These results suggest that PA and BER may be useful as therapeutic agents for improving cognitive functioning by stimulating cholinergic enzyme activity and alleviating inflammatory responses.

PPARγ agonist pioglitazone improves scopolamine-induced memory impairment in mice

Objectives

This study was conducted to evaluate the effects of exposure to pioglitazone, a peroxisome proliferator-activated receptor agonist, on cognitive impairment induced by scopolamine, a muscarinic antagonist, in mice.

Methods

Pioglitazone (9 mg/kg, 18 mg/kg) was orally administered for 9 days at 30 min before intraperitoneal injection with scopolamine (0.8 mg/kg, i.p.). Cognitive function was evaluated by the passive avoidance test and the Morris water maze test on the 10th day after treatment. Changes in cholinergic system reactivity were also examined by measuring the acetylcholine, acetylcholinesterase and choline acetyltransferase in the hippocampus and cortex.

Key findings

Scopolamine injection induced impaired performance in the passive avoidance test and the water maze test and severe decrease of cholinergic system reactivity, as indicated by reduced acetylcholine levels, decreased choline acetyltransferase activity and increased acetylcholinesterase activity. Daily administration of pioglitazone significantly increased step-through latency in passive avoidance test, and significantly decreased the escape latency, and increased the time spent in the platform quadrant in the Morris water maze test. Pioglitazone also protected against scopolamine-induced cholinergic system deficit, including reduced acetylcholine levels, decreased choline acetyltransferase activity and increased acetylcholinesterase activity in the hippocampus or cortex.

Conclusions

Pioglitazone demonstrates a significant neuroprotective effect against scopolamine-induced cholinergic system deficit and cognitive impairment.

Protective role of Ashwagandha leaf extract and its component withanone on scopolamine-induced changes in the brain and brain-derived cells

Background

Scopolamine is a well-known cholinergic antagonist that causes amnesia in human and animal models. Scopolamine-induced amnesia in rodent models has been widely used to understand the molecular, biochemical, behavioral changes, and to delineate therapeutic targets of memory impairment. Although this has been linked to the decrease in central cholinergic neuronal activity following the blockade of muscarinic receptors, the underlying molecular and cellular mechanism(s) particularly the effect on neuroplasticity remains elusive. In the present study, we have investigated (i) the effects of scopolamine on the molecules involved in neuronal and glial plasticity both in vivo and in vitro and (ii) their recovery by alcoholic extract of Ashwagandha leaves (i-Extract).

Methodology/Principal Findings

As a drug model, scopolamine hydrobromide was administered intraperitoneally to mice and its effect on the brain function was determined by molecular analyses. The results showed that the scopolamine caused downregulation of the expression of BDNF and GFAP in dose and time dependent manner, and these effects were markedly attenuated in response to i-Extract treatment. Similar to our observations in animal model system, we found that the scopolamine induced cytotoxicity in IMR32 neuronal and C6 glioma cells. It was associated with downregulation of neuronal cell markers NF-H, MAP2, PSD-95, GAP-43 and glial cell marker GFAP and with upregulation of DNA damage- γH2AX and oxidative stress- ROS markers. Furthermore, these molecules showed recovery when cells were treated with i-Extract or its purified component, withanone.

Conclusion

Our study suggested that besides cholinergic blockade, scopolamine-induced memory loss may be associated with oxidative stress and Ashwagandha i-Extract, and withanone may serve as potential preventive and therapeutic agents for neurodegenerative disorders and hence warrant further molecular analyses.