Lactucopicrin ameliorates oxidative stress mediated by scopolamine-induced neurotoxicity through activation of the NRF2 pathway

Anti-Amnesic Effect of Agastache rugosa on Scopolamine-Induced Memory Impairment in Mice

Agastache rugosa, a traditional Asian herbal medicine, is primarily used for digestive problems; yet, its cognitive benefits remain unexplored. This study evaluated the anti-amnesic effects of A. rugosa extract (ARE) on scopolamine (SCO)-induced memory impairment in mice. Mice received 100 or 200 mg/kg ARE orally for 5 days, followed by SCO injection. The ARE demonstrated significant antioxidant (DPPH IC50: 75.3 µg/mL) and anti-inflammatory effects (NO reduction). Furthermore, the ARE significantly improved memory performance in the passive avoidance test (escape latency: 157.2 s vs. 536.9 s), the novel object recognition test (novel object preference: 47.6% vs. 66.3%) and the Morris water maze (time spent in the target quadrant: 30.0% vs. 45.1%). The ARE reduced hippocampal acetylcholinesterase activity (1.8-fold vs. 1.1-fold) while increasing choline acetyltransferase (0.4-fold vs. 1.0-fold) and muscarinic acetylcholine receptor subtype I (0.3-fold vs. 1.6-fold) expression. The ARE improved hippocampal neurogenesis via doublecortin- (0.4-fold vs. 1.1-fold) and KI-67-positive (6.3 vs. 12.0) cells. Therefore, the ARE exerts protective effects against cognitive decline through cholinergic system modulation and antioxidant activity, supporting its potential use as a cognitive enhancer.

Real-Time Analysis of Neuronal Cell Cultures for CNS Drug Discovery

The ability to screen for agents that can promote the development and/or maintenance of neuronal networks creates opportunities for the discovery of novel agents for the treatment of central nervous system (CNS) disorders. Over the past 10 years, advances in robotics, artificial intelligence, and machine learning have paved the way for the improved implementation of live-cell imaging systems for drug discovery. These instruments have revolutionized our ability to quickly and accurately acquire large standardized datasets when studying complex cellular phenomena in real-time. This is particularly useful in the field of neuroscience because real-time analysis can allow efficient monitoring of the development, maturation, and conservation of neuronal networks by measuring neurite length. Unfortunately, due to the relative infancy of this type of analysis, standard practices for data acquisition and processing are lacking, and there is no standardized format for reporting the vast quantities of data generated by live-cell imaging systems. This paper reviews the current state of live-cell imaging instruments, with a focus on the most commonly used equipment (IncuCyte systems). We provide an in-depth analysis of the experimental conditions reported in publications utilizing these systems, particularly with regard to studying neurite outgrowth. This analysis sheds light on trends and patterns that will enhance the use of live-cell imaging instruments in CNS drug discovery.

Neuroprotective effect of ranolazine improves behavioral discrepancies in a rat model of scopolamine-induced dementia

Background

Ranolazine (Rn), an antianginal agent, acts in the central nervous system and has been used as a potential treatment agent for pain and epileptic disorders. Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases and the leading factor in dementia in the elderly.

Aim

We examined the impact of Rn on scopolamine (Sco)-induced dementia in rats.

Methods

Thirty-two albino male rats were divided into four groups: control, Rn, Sco, and Rn + Sco.

Results

A significant decrease in the escape latency in the Morris water maze test after pre-treatment with Rn explained better learning and memory in rats. Additionally, Rn significantly upregulated the activities of the antioxidant enzymes in the treated group compared to the Sco group but substantially reduced acetylcholinesterase activity levels in the hippocampus. Moreover, Rn dramatically reduced interleukin-1 β (IL-1β) and IL-6 and upregulated the gene expression of brain-derived neurotrophic factor (BDNF). Furthermore, in the Sco group, the hippocampal tissue's immunohistochemical reaction of Tau and glial factor activating protein (GFAP) was significantly increased in addition to the upregulation of the Caspase-3 gene expression, which was markedly improved by pre-treatment with Rn. The majority of pyramidal neurons had large vesicular nuclei with prominent nucleoli and appeared to be more or less normal, reflecting the all-beneficial effects of Rn when the hippocampal tissue was examined under a microscope.

Conclusion

Our findings indicated that Rn, through its antioxidative, anti-inflammatory, and anti-apoptotic effects, as well as the control of the expression of GFAP, BDNF, and Tau proteins, has a novel neuroprotective impact against scopolamine-induced dementia in rats.

Multi-omics reveals aspirin eugenol ester alleviates neurological disease

BACKGROUND

Exosomes play an essential role in maintaining normal brain function due to their ability to cross the blood-brain barrier. Aspirin eugenol ester (AEE) is a new medicinal compound synthesized by the esterification of aspirin with eugenol using the prodrug principle. Aspirin has been reported to have neuroprotective effects and may be effective against neurodegenerative diseases.

PURPOSE

This study wanted to investigate how AEE affected neurological diseases in vivo and in vitro.

EXPERIMENTAL APPROACH

A multi-omics approach was used to explore the effects of AEE on the nervous system. Gene and protein expression changes of BDNF and NEFM in SY5Y cells after AEE treatment were detected using RT-qPCR and Western Blot.

KEY RESULTS

The multi-omics results showed that AEE could regulate neuronal synapses, neuronal axons, neuronal migration, and neuropeptide signaling by affecting transport, inflammatory response, and regulating apoptosis. Exosomes secreted by AEE-treated Caco-2 cells could promote the growth of neurofilaments in SY5Y cells and increased the expression of BDNF and NEFM proteins in SY5Y cells. miRNAs in the exosomes of AEE-treated Caco-2 cells may play an important role in the activation of SY5Y neuronal cells.

CONCLUSIONS

In conclusion, AEE could play positive effects on neurological-related diseases.

The neurobiology and therapeutic potential of multi-targeting β-secretase, glycogen synthase kinase 3β and acetylcholinesterase in Alzheimer's disease

Alzheimer's Disease (AD) is the most common form of dementia, affecting almost 50 million of people around the world, characterized by a complex and age-related progressive pathology with projections to duplicate its incidence by the end of 2050. AD pathology has two major hallmarks, the amyloid beta (Aβ) peptides accumulation and tau hyperphosphorylation, alongside with several sub pathologies including neuroinflammation, oxidative stress, loss of neurogenesis and synaptic dysfunction. In recent years, extensive research pointed out several therapeutic targets which have shown promising effects on modifying the course of the disease in preclinical models of AD but with substantial failure when transposed to clinic trials, suggesting that modulating just an isolated feature of the pathology might not be sufficient to improve brain function and enhance cognition. In line with this, there is a growing consensus that an ideal disease modifying drug should address more than one feature of the pathology. Considering these evidence, β-secretase (BACE1), Glycogen synthase kinase 3β (GSK-3β) and acetylcholinesterase (AChE) has emerged as interesting therapeutic targets. BACE1 is the rate-limiting step in the Aβ production, GSK-3β is considered the main kinase responsible for Tau hyperphosphorylation, and AChE play an important role in modulating memory formation and learning. However, the effects underlying the modulation of these enzymes are not limited by its primarily functions, showing interesting effects in a wide range of impaired events secondary to AD pathology. In this sense, this review will summarize the involvement of BACE1, GSK-3β and AChE on synaptic function, neuroplasticity, neuroinflammation and oxidative stress. Additionally, we will present and discuss new perspectives on the modulation of these pathways on AD pathology and future directions on the development of drugs that concomitantly target these enzymes.

Polygoni Multiflori Radix Praeparata and Acori Tatarinowii Rhizoma ameliorate scopolamine-induced cognitive impairment by regulating the cholinergic and synaptic associated proteins

ETHNOPHARMACOLOGICAL RELEVANCE

The combination of Polygoni Multiflori Radix Praeparata (PMRP) and Acori Tatarinowii Rhizoma (ATR) is often used in traditional Chinese medicine to prevent and treat Alzheimer's disease (AD). However, it is not clear whether the effects and mechanisms of the decoction prepared by traditional decocting method (PA) is different from that prepared by modern decocting method (P + A).

AIM OF THE STUDY

The present study aimed to investigate the differences in the protective effects of PA and P + A on scopolamine induced cognitive impairment, and to explore its potential mechanism.

MATERIALS AND METHODS

To assess the protective effect of PA and P + A on cognitive dysfunction, the mice were orally administrated with PA (1.56, 6.24 g kg^-1•day^-1) and P + A (1.56, 6.24 g kg^-1•day^-1) for 26 days before co-treatment with scopolamine (4 mg kg^-1•day^-1, i.p.). The learning and memory abilities of mice were examined by Morris water maze test, and the expressions of proteins related to cholinergic system and synaptic function were detected by the methods of ELISA, real-time PCR and Western blotting. Then, molecular docking technique was used to verify the effect of active compounds in plasma after PA administration on Acetylcholinesterase (AChE) protein. Finally, the Ellman method was used to evaluate the effects of different concentrations of PA, P + A (1 μg/mL-100 mg/mL) and the compounds (1-100 μM) on AChE activity in vitro.

RESULTS

On one hand, in the scopolamine-induced cognitive impairment mouse model, both of PA and P + A could improve the cognitive impairment, while the effect of PA on cognitive amelioration was better than that of P + A. Moreover, PA regulated the cholinergic and synaptic functions by enhancing the concentration of acetylcholine (ACh), the mRNA levels of CHT1, Syn, GAP-43 and PSD-95, and the related proteins (CHT1, VACHT, Syn, GAP-43 and PSD-95), and significantly inhibiting the expression of AChE protein. Meanwhile, P + A only up-regulated the mRNA levels of GAP-43 and PSD-95, increased the expressions of CHT1, VACHT, Syn, GAP-43 and PSD-95 proteins, and inhibited the expression of AChE protein. On the other hand, the in vitro study showed that some compounds including emodin-8-o-β-d-Glucopyranoside, THSG and α-Asarone inhibited AChE protein activity with the IC₅₀ values 3.65 μM, 5.42 μM and 9.43 μM, respectively.

CONCLUSIONS

These findings demonstrate that both of PA and P + A can ameliorate the cognitive deficits by enhancing cholinergic and synaptic related proteins, while PA has the stronger improvement effect on the cholinergic function, which may be attributed to the compounds including THSG, emodin, emodin-8-O-β-D-glucopyranoside and α-asarone. The present study indicated that PA has more therapeutic potential in the treatment of neurodegenerative diseases such as AD. The results provide the experimental basis for the clinical use of PA.

Folicitin abrogates scopolamine induced oxidative stress, hyperlipidemia mediated neuronal synapse and memory dysfunction in mice

No effective drug treatment is available for Alzheimer disease, thus the need arise to develop efficient drugs for its treatment. Natural products have pronounced capability in treating Alzheimer disease therefore current study aimed to evaluate the neuro-protective capability of folicitin against scopolamine-induced Alzheimer disease neuropathology in mice. Experimental mice were divided into four groups i.e. control (single dose of 250 μL saline), scopolamine-administered group (1 mg/kg administered for three weeks), scopolamine plus folicitin-administered group (scopolamine 1 mg/kg administration for three weeks followed by folicitin administration for last two weeks) and folicitin-administered group (20 mg/kg administered for 5 alternate days). Results of behavioral tests and Western blot indicated that folicitin has the capability of recovering the memory against scopolamine-induced memory impairment by reducing the oxidative stress through up-regulating the endogenous antioxidant system like nuclear factor erythroid 2-related factor and Heme oxygenase-1 while prohibiting phosphorylated c-Jun N-terminal kinase. Similarly, folicitin also improved the synaptic dysfunction by up-regulating SYP and PSD95. Scopolamine-induced hyperglycemia and hyperlipidemia were abolished by folicitin as evidenced through random blood glucose test, glucose tolerance test and lipid profile test. All these results revealed that folicitin being a potent anti-oxidant is capable of improving synaptic dysfunction and reducing oxidative stress through Nrf-2/HO-1 pathway, thus plays a key role in treating Alzheimer disease as well as possess hyperglycemic and hyperlipidemic effect. Furthermore, a detailed study is suggested.

Sesamol Attenuates Scopolamine-Induced Cholinergic Disorders, Neuroinflammation, and Cognitive Deficits in Mice

Alzheimer's disease (AD) is a neurodegenerative disease, characterized by memory loss and cognitive deficits accompanied by neuronal damage and cholinergic disorders. Sesamol, a lignan component in sesame oil, has been proven to have neuroprotective effects. This research aimed to investigate the preventive effects of sesamol on scopolamine (SCOP)-induced cholinergic disorders in C57BL/6 mice. The mice were pretreated with sesamol (100 mg/kg/d, p.o.) for 30 days. Behavioral tests indicated that sesamol supplement prevented SCOP-induced cognitive deficits. Sesamol enhanced the expression of neurotrophic factors and postsynaptic density (PSD) in SCOP-treated mice, reversing neuronal damage and synaptic dysfunction. Importantly, sesamol could balance the cholinergic system by suppressing the AChE activity and increasing the ChAT activity and M1 mAChR expression. Sesamol treatment also inhibited the expression of inflammatory factors and overactivation of microglia in SCOP-treated mice. Meanwhile, sesamol improved the antioxidant enzyme activity and suppressed oxidative stress in SCOP-treated mice and ameliorated the oxidized cellular status and mitochondrial dysfunction in SCOP-treated SH-SY5Y cells. In conclusion, these results indicated that sesamol attenuated SCOP-induced cognitive dysfunction via balancing the cholinergic system and reducing neuroinflammation and oxidative stress.

Role of Cholinergic Signaling in Alzheimer's Disease

Acetylcholine, a neurotransmitter secreted by cholinergic neurons, is involved in signal transduction related to memory and learning ability. Alzheimer’s disease (AD), a progressive and commonly diagnosed neurodegenerative disease, is characterized by memory and cognitive decline and behavioral disorders. The pathogenesis of AD is complex and remains unclear, being affected by various factors. The cholinergic hypothesis is the earliest theory about the pathogenesis of AD. Cholinergic atrophy and cognitive decline are accelerated in age-related neurodegenerative diseases such as AD. In addition, abnormal central cholinergic changes can also induce abnormal phosphorylation of ttau protein, nerve cell inflammation, cell apoptosis, and other pathological phenomena, but the exact mechanism of action is still unclear. Due to the complex and unclear pathogenesis, effective methods to prevent and treat AD are unavailable, and research to explore novel therapeutic drugs is various and active in the world. This review summaries the role of cholinergic signaling and the correlation between the cholinergic signaling pathway with other risk factors in AD and provides the latest research about the efficient therapeutic drugs and treatment of AD.

A Mixture of Ginkgo biloba L. Leaf and Hericium erinaceus (Bull.) Pers. Fruit Extract Attenuates Scopolamine-Induced Memory Impairments in Mice

Alzheimer's disease (AD) is a neurodegenerative disease that is characterized by loss of memory and cognitive impairment via dysfunction of the cholinergic nervous system. In cholinergic dysfunction, it is well known that impaired cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) signaling are major pathological markers and are some of the strategies for the development of AD therapy. Therefore, this study is aimed at evaluating whether a mixture comprising Ginkgo biloba L. leaf (GL) and Hericium erinaceus (Bull.) Pers. (HE) fruit extract (GH mixture) alleviated cognitive impairment induced in a scopolamine-induced model. It was discovered that GH reduced neuronal apoptosis and promoted neuronal survival by activating BDNF signaling in an in vitro assay. In addition, the GH (p.o. 240 mg/kg) oral administration group significantly restored the cognitive deficits of the scopolamine-induced mouse group (i.p. 1.2 mg/kg) in the behavior tests such as Y-maze and novel object recognition task (NORT) tests. This mixture also considerably enhanced cholinergic system function in the mouse brain. Furthermore, GH markedly upregulated the expressed levels of extracellular signal-regulated kinase (ERK), CREB, and BDNF protein levels. These results demonstrated that GH strongly exerted a neuroprotective effect on the scopolamine-induced mouse model, suggesting that an optimized mixture of GL and HE could be used as a good material for developing functional foods to aid in the prevention of neurodegenerative diseases, including AD.

Development of novel 2-aminoalkyl-6-(2-hydroxyphenyl)pyridazin-3(2H)-one derivatives as balanced multifunctional agents against Alzheimer's disease

Based on multitarget-directed ligands approach, through two rounds of screening, a series of 2-aminoalkyl-6-(2-hydroxyphenyl)pyridazin-3(2H)-one derivatives were designed, synthesized and evaluated as innovative multifunctional agents against Alzheimer's disease. In vitro biological assays indicated that most of the hybrids were endowed with great AChE inhibitory activity, excellent antioxidant activity and moderate Aβ_1-42 aggregation inhibition. Taken both efficacy and balance into account, 12a was identified as the optimal multifunctional ligand with significant inhibition of AChE (EeAChE, IC₅₀ = 0.20 μM; HuAChE, IC₅₀ = 37.02 nM) and anti-Aβ activity (IC₅₀ = 1.92 μM for self-induced Aβ_1-42 aggregation; IC₅₀ = 1.80 μM for disaggregation of Aβ_1-42 fibrils; IC₅₀ = 2.18 μM for Cu²⁺-induced Aβ_1-42 aggregation; IC₅₀ = 1.17 μM for disaggregation of Cu²⁺-induced Aβ_1-42 fibrils; 81.7% for HuAChE-induced Aβ_1-40 aggregation). Moreover, it was equipped with the potential to serve as antioxidant (3.03 Trolox equivalents), metals chelator and anti-neuroinflammation agent for synergetic treatment. Finally, in vivo study demonstrated that 12a, with suitable BBB permeability (log BB = -0.61), could efficaciously ameliorate cognitive dysfunction on scopolamine-treated mice by regulating cholinergic system and oxidative stress simultaneously. Altogether, these results highlight the potential of 12a as an innovative balanced multifunctional candidate for Alzheimer's disease treatment.

Terpene Lactucopicrin Limits Macrophage Foam Cell Formation by a Reduction of Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 in Lipid Rafts

SCOPE

Sustained inflammation promotes macrophage foam cell formation by promoting cholesterol influx and impairing cholesterol efflux. Terpene lactucopicrin, affluent in vegetables of the Asteraceae family (e.g., chicory, curly escarole, and lettuce) can inhibit atherogenesis in mice. However, it remains unknown whether and how lactucopicrin regulates macrophage foam cell formation.

METHODS AND RESULTS

Lactucopicrin at physiologically reachable concentrations inhibits oxidized low-density lipoprotein (oxLDL)-induced foam cell formation in inflammatory mouse bone marrow derived macrophages established by 50 pg mL^-1 of LPS, reachable level in patients with metabolic endotoxemia. This effect is not due to modulation of cholesterol efflux, but reliant on a reduction in lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1)-mediated cholesterol influx. Mechanistically, lactucopicrin does not affect LOX-1 expression, cellular oxidative stress, and exocytosis, known mechanisms regulating LOX-1 function in cholesterol influx. Strikingly, lactucopicrin selectively decreases LOX-1 content in lipid rafts, an effect responsible for the lactucopicrin effect on cholesterol influx. Moreover, ApoE^-/- mice fed a high fat diet supplemented with lactucopicrin for 12 weeks display fewer macrophage foam cells within atherosclerotic plaques relative to the control mice.

CONCLUSION

Lactucopicrin limits macrophage foam cell formation through a reduction of LOX-1 distribution in lipid rafts, thus contributing to its atheroprotective effect.

Protective Effects of Inosine on Memory Consolidation in a Rat Model of Scopolamine-Induced Cognitive Impairment: Involvement of Cholinergic Signaling, Redox Status, and Ion Pump Activities

This study investigated the effects of inosine on memory acquisition and consolidation, cholinesterases activities, redox status and Na⁺, K⁺-ATPase activity in a rat model of scopolamine-induced cognitive impairment. Adult male rats were divided into four groups: control (saline), scopolamine (1 mg/kg), scopolamine plus inosine (50 mg/kg), and scopolamine plus inosine (100 mg/kg). Inosine was pre-administered for 7 days, intraperitoneally. On day 8, scopolamine was administered pre (memory acquisition protocol) or post training (memory consolidation protocol) on inhibitory avoidance tasks. The animals were subjected to the step-down inhibitory avoidance task 24 hours after the training. Scopolamine induced impairment in the acquisition and consolidation phases; however, inosine was able to prevent only the impairment in memory consolidation. Also, scopolamine increased the activity of acetylcholinesterase and reduced the activity of Na⁺, K⁺-ATPase and the treatment with inosine protected against these alterations in consolidation protocol. In the animals treated with scopolamine, inosine improved the redox status by reducing the levels of reactive oxygen species and thiobarbituric acid reactive substances and restoring the activity of the antioxidant enzymes, superoxide dismutase and catalase. Our findings suggest that inosine may offer protection against scopolamine-induced memory consolidation impairment by modulating brain redox status, cholinergic signaling and ion pump activity. This compound may provide an interesting approach in pharmacotherapy and as a prophylactic against neurodegenerative mechanisms involved in Alzheimer's disease.

Synthesis, characterization and antitumor mechanism investigation of ruthenium(II) polypyridyl complexes with artesunate moiety

Six artesunate (ART) conjugated ruthenium(II) complexes (Ru(II)-ART conjugates) with the formula [Ru(N^N)₂bpy(4-CH₃-4'-CH₂OART)](PF₆)₂ (Ru-ART-1-3) and [Ru(N^N)₂bpy(4-CH₂OART-4'-CH₂OART)](PF₆)₂ (Ru-ART-4-6) (N^N = 2,2'-bipyridine (bpy, in Ru-ART-1 and Ru-ART-4), 1,10-phenanthroline (phen, in Ru-ART-2 and Ru-ART-5) and 4,7-diphenyl-1,10-phenanthroline (DIP, in Ru-ART-3 and Ru-ART-6)), were synthesized and characterized. Among them, Ru-ART-1-3 and Ru-ART-4-6 carry one and two ART moieties, respectively. Ru-ART-3 and Ru-ART-6 exhibit better cytotoxicity among six Ru(II)-ART conjugates. These two complexes can be effectively taken up by human cervical carcinoma (HeLa) cells. In addition, they selectively kill cancer cell lines while mildly affect normal cells. Mechanism studies have shown that HeLa cells treated with Ru-ART-3 and Ru-ART-6 show typical apoptotic characteristics (morphology changes, mitochondrial dysfunction, caspase cascade, etc.). On the other hand, the up regulation of Beclin-1 and conversion of LC3-I to LC3-II note the appearance of autophagy. As a result, Ru-ART-3 and Ru-ART-6 induce autophagy-dependent cell apoptosis via mitochondrial dysfunction and reactive oxygen species (ROS) accumulation. In this work, six artesunate (ART) conjugated ruthenium(II) complexes (Ru(II)-ART conjugates) have been synthesized and characterized. Among them, Ru-ART-3 and Ru-ART-6 exhibit better cytotoxicity. Mechanism studies have shown that HeLa cells treated with Ru-ART-3 and Ru-ART-6 show typical apoptotic characteristics (morphology changes, mitochondrial dysfunction, caspase cascade, etc.). On the other hand, the up regulation of Beclin-1 and conversion of LC3-I to LC3-II note the appearance of autophagy.

Allium hookeri Extracts Improve Scopolamine-Induced Cognitive Impairment via Activation of the Cholinergic System and Anti-Neuroinflammation in Mice

Allium hookeri (AH) is a medicinal food that has been used in Southeast Asia for various physiological activities. The objective of this study was to investigate the activation of the cholinergic system and the anti-neuroinflammation effects of AH on scopolamine-induced memory impairment in mice. Scopolamine (1 mg/kg body weight, i.p.) impaired the performance of the mice on the Y-maze test, passive avoidance test, and water maze test. However, the number of error actions was reduced in the AH groups supplemented with leaf and root extracts from AH. AH treatment improved working memory and avoidance times against electronic shock, increased step-through latency, and reduced the time to reach the escape zone in the water maze test. AH significantly improved the cholinergic system by decreasing acetylcholinesterase activity, and increasing acetylcholine concentration. The serum inflammatory cytokines (IL-1β, IL-6, and IFN-γ) increased by scopolamine treatment were regulated by the administration of AH extracts. Overexpression of NF-κB signaling and cytokines in liver tissue due to scopolamine were controlled by administration of AH extracts. AH also significantly decreased Aβ and caspase-3 expression but increased NeuN and ChAT. The results suggest that AH extracts improve cognitive effects, and the root extracts are more effective in relieving the scopolamine-induced memory impairment. They have neuroprotective effects and reduce the development of neuroinflammation.

Dietary supplementation with Ceriporia lacerata improves learning and memory in a scopolamine-induced amnesia mouse model

Ceriporia lacerata (CL) is a species of white rot fungi. In this study, we have examined the beneficial effect of CL on scopolamine-induced memory impairment in mice. A freeze-dried CL mycelial culture broth was dissolved and orally administered to scopolamine-treated C57BL/6J mice followed by behavioral tests using the Y-maze, passive avoidance, and Morris water maze tasks. CL administration at a daily dose of 200 mg/kg body weight resulted in restoration of exploration reduction and improvement of associative and spatial learning and memory impairment in scopolamine-treated mice. Concomitantly, heme oxygenase-1 was highly expressed in the hippocampal region of CL-administered mice. Moreover, the ethanolic extract of CL significantly increased the transcriptional activity of antioxidant response element and attenuated the glutamate-induced cytotoxicity in HT22 mouse hippocampal neuronal cells. These findings suggest that the CL intake can confer a beneficial effect on learning and memory presumably through protecting hippocampal neuronal cells from oxidative stress-induced damage.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10068-021-00945-5.

Effect of buscopan, a compound that alleviates cramps, on the developing nervous system of the chick embryo

BACKGROUND

Buscopan is used to treat stomach cramps including those resulting from irritable bowel syndrome, bladder cramps, and pain related to menstruation. Its pregnancy category is determined as C. It has been shown in experimental animal studies that the drug has a negative effect on the embryo, but sufficient and well-controlled studies have not been conducted in humans. The aim of this study is to investigate effects of buscopan on the development of the neural tube (NT) in chick embryos.

METHODS

Sixty specific pathogen-free (SPF) fertilized eggs were used. SPF eggs were placed in an incubator and divided into six groups at 28 hr of incubation. Five different doses (low to high) of buscopan were injected sub-blastodermally. At the end of 48 hr, the embryos were evaluated morphologically and histopathologically. The argyrophilic nucleolar-organizing region (AgNOR) method was used in this study to determine the proliferation activity of cells in NT development in chick embryos. AgNOR number and total AgNOR area/nuclear area (TAA/NA) were detected for each embryo.

RESULTS

Depending on the dose, the embryo's crown-rump length and somite number decreased (p < .05). Significant differences were detected among all groups for mean AgNOR number (p < .05) and TAA/NA ratio (p < .05).

CONCLUSIONS

Considering the average count of AgNOR cells and TAA/NA ratio, it was found that there was a decrease in cell division depending on the dose. It was determined that buscopan treatment on chick embryos adversely affected early nervous system and NT development.

Anxiolytic, Promnesic, Anti-Acetylcholinesterase and Antioxidant Effects of Cotinine and 6-Hydroxy-L-Nicotine in Scopolamine-Induced Zebrafish (Danio rerio) Model of Alzheimer's Disease

Cotinine (COT) and 6-hydroxy-L-nicotine (6HLN) are two nicotinic derivatives that possess cognitive-improving abilities and antioxidant properties in different rodent models of Alzheimer's disease (AD), eluding the side-effects of nicotine (NIC), the parent molecule. In the current study, we evaluated the impact of COT and 6HLN on memory deterioration, anxiety, and oxidative stress in the scopolamine (SCOP)-induced zebrafish model of AD. For this, COT and 6HLN were acutely administered by immersion to zebrafish that were treated with SCOP before testing. The memory performances were assessed in Y-maze and object discrimination (NOR) tasks, while the anxiety-like behavior was evaluated in the novel tank diving test (NTT). The acetylcholinesterase (AChE) activity and oxidative stress were measured from brain samples. The RT-qPCR analysis was used to evaluate the npy, egr1, bdnf, and nrf2a gene expression. Our data indicated that both COT and 6HLN attenuated the SCOP-induced anxiety-like behavior and memory impairment and reduced the oxidative stress and AChE activity in the brain of zebrafish. Finally, RT-qPCR analysis indicated that COT and 6HLN increased the npy, egr1, bdnf, and nrf2a gene expression. Therefore, COT and 6HLN could be used as tools for improving AD conditions.

Low Oral Bioavailability and Partial Gut Microbiotic and Phase II Metabolism of Brussels/Witloof Chicory Sesquiterpene Lactones in Healthy Humans

Free and glycosylated sesquiterpene lactones (SLs), which are abundant in leafy vegetables including Brussels/witloof chicory, possess health-promoting effects in vivo. However, the pharmacokinetics of dietary source of SLs remain largely unknown. In this open-label and single-dose trial, sixteen healthy volunteers consumed 150 g of Brussels/witloof chicory juice containing 48.77 μmol SLs in 5 min. Blood, urine, and fecal samples were collected before and after chicory consumption in 24 h. No SLs were detected in the serum, urine, and fecal samples before chicory consumption in all of the participants. Chicory consumption increased lactucin, 11β,13-dihydrolactucin, and their glucuronide/sulfate conjugates, rather than lactucopicrin and 11β,13-dihydrolactucopicrin, as well as glycosylated SLs in biological samples. The peak concentration of total SLs in serum reached 284.46 nmol/L at 1 h, while, in urine, this peak was 220.3 nmol between 2 and 6 h. The recovery of total SLs in blood, urine, and feces was 7.03%, 1.13%, and 43.76% of the ingested dose, respectively. Human fecal suspensions with intestinal microbiota degraded glycosylated SLs in chicory, and converted lactucopicrin and 11β,13-dihydrolactucopicrin to lactucin and 11β,13-dihydrolactucin, respectively. Collectively, Brussels/witloof chicory SLs are poorly bioavailable and they undergo partial gut microbial and phase II metabolism in humans.

6-Paradol and its glucoside improve memory disorder in mice

In this study, the effects of 6-paradol (6P) and 6-paradol-β-glucoside (6PG) on neuritogenesis were investigated using PC12 cells. Treatment with 200 μM 6P or 6PG and nerve growth factor (NGF) (5 ng mL-1) increased the number of elongated dendritic cells 8.7 and 5.4 times, respectively, compared to that with NGF (5 ng mL-1) treatment alone. 6P and 6PG did not stimulate the phosphorylation of extracellular regulated protein kinases (ERK)1/2 and cAMP response element-binding protein (CREB) in the tropomyosin receptor kinase A (TrkA) pathway as their activities were suppressed by the pathway inhibitor, k252a. 6P enhanced Ca2+ influx into the cells, whereas 6PG had no effect on Ca2+ influx, although it stimulated PC12 cell differentiation. High-performance liquid chromatography (HPLC) analysis of 6PG in PC12 culture medium suggested that 6PG was deglycosylated to generate 6P, which exhibited the effect. Furthermore, the bioactivities of 6P and 6PG were investigated in mice, and the results revealed that they ameliorated short-term memory loss in animals during behavioral testing.

Attenuation of Nrf2/Keap1/ARE in Alzheimer's Disease by Plant Secondary Metabolites: A Mechanistic Review

Alzheimer’s disease (AD) is a progressive neuronal/cognitional dysfunction, leading to disability and death. Despite advances in revealing the pathophysiological mechanisms behind AD, no effective treatment has yet been provided. It urges the need for finding novel multi-target agents in combating the complex dysregulated mechanisms in AD. Amongst the dysregulated pathophysiological pathways in AD, oxidative stress seems to play a critical role in the pathogenesis progression of AD, with a dominant role of nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein-1 (Keap1)/antioxidant responsive elements (ARE) pathway. In the present study, a comprehensive review was conducted using the existing electronic databases, including PubMed, Medline, Web of Science, and Scopus, as well as related articles in the field. Nrf2/Keap1/ARE has shown to be the upstream orchestrate of oxidative pathways, which also ameliorates various inflammatory and apoptotic pathways. So, developing multi-target agents with higher efficacy and lower side effects could pave the road in the prevention/management of AD. The plant kingdom is now a great source of natural secondary metabolites in targeting Nrf2/Keap1/ARE. Among natural entities, phenolic compounds, alkaloids, terpene/terpenoids, carotenoids, sulfur-compounds, as well as some other miscellaneous plant-derived compounds have shown promising future accordingly. Prevailing evidence has shown that activating Nrf2/ARE and downstream antioxidant enzymes, as well as inhibiting Keap1 could play hopeful roles in overcoming AD. The current review highlights the neuroprotective effects of plant secondary metabolites through targeting Nrf2/Keap1/ARE and downstream interconnected mediators in combating AD.

Ameliorative Effects of Rhoifolin in Scopolamine-Induced Amnesic Zebrafish (Danio rerio) Model

Rhoifolin (Rho) exerts many biological activities such as anticancer, antidiabetic, hepatoprotective, antirheumatic, antibacterial, and antiviral properties. The neuroprotective action of this compound has not been studied. The goal of this study was to investigate the improvement impact of Rho on scopolamine (Sco)-induced zebrafish anxiety, amnesia, and brain oxidative stress and to elucidate the underlying mechanisms involved. Zebrafish were treated with Rho (1, 3, and 5 μg/L) for nine consecutive days and were subsequently subjected to Sco (100 μM) 30 min before behavioral tests (novel tank diving test, Y-maze, and novel object recognition tests). Rho was isolated from Chorisia crispiflora (Malvaceae) leaves and identified by different spectroscopic techniques. To further assess the possible mechanisms of Rho in enhancing the memory capacities in zebrafish, the in vivo antioxidant status and acetylcholinesterase (AChE) activity was also evaluated. Rho from Chorisia crispiflora leaves was identified. Rho could alleviate anxiety, memory deficits, and brain oxidative stress in Sco-treated zebrafish and could regulate the cholinergic function by inhibiting the AChE activity. Our results demonstrated that Rho could be a promising candidate compound against anxiety and amnesia by restoring the cholinergic activity and the amelioration of brain oxidative stress.

Neuroprotective Effects of Euonymus alatus Extract on Scopolamine-Induced Memory Deficits in Mice

Euonymus alatus is considered to elicit various beneficial effects against cancer, hyperglycemia, menstrual discomfort, diabetic complications, and detoxification. The young leaves of this plant are exploited as food and also utilized for traditional medicine in East Asian countries, including Korea and China. Our preliminary study demonstrated that ethanolic extract from the Euonymus alatus leaf (EAE) exhibited the strongest antioxidant enzyme-inducing activity among more than 100 kinds of edible tree leaf extracts. This study investigated whether EAE could attenuate the cognitive deficits caused by oxidative stress in mice. Oral intubation of EAE at 100 mg/kg bw or higher resulted in significant improvements to the memory and behavioral impairment induced via i.p. injection of scopolamine. Furthermore, EAE enhanced the expression levels of hippocampal neurotrophic factors such as brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor in mice, activated the Nrf2, and the downstream heme oxygenase-1 (HO-1) a quintessential antioxidant enzyme. As rutin (quercetin-3-O-rutinose) was abundantly present in EAE and free quercetin was able to induce defensive antioxidant enzymes in an Nrf2-dependent manner, our findings suggested that quercetin derived from rutin via the intestinal microflora played a significant role in the protection of the mouse hippocampus from scopolamine-induced damage through BDNF-mediated Nrf2 activation, thereby dampening cognitive decline.

QTC-4-MeOBnE Rescues Scopolamine-Induced Memory Deficits in Mice by Targeting Oxidative Stress, Neuronal Plasticity, and Apoptosis

Cognitive decline and memory impairment induced by disruption of cholinergic neurons and oxidative brain damage are among the earliest pathological hallmark signatures of Alzheimer's disease. Scopolamine is a postsynaptic muscarinic receptor blocker which causes impairment of cholinergic transmission resulting in cognitive deficits. Herein we investigated the effect of QTC-4-MeOBnE (1-(7-chloroquinolin-4-yl)-N-(4-methoxybenzyl)-5-methyl-1H-1,2,3-triazole-4-carboxamide) on memory impairments in mice chronically treated with scopolamine and the molecular mechanisms involved. Administration of scopolamine (1 mg/kg) for 15 days resulted in significant impairments in working and short-term memory in mice, as assessed by the novel object recognition and the Y-maze paradigms. However, both deficits were prevented if mice receiving the scopolamine were also treated with QTC-4-MeOBnE. This effect was associated with an increase in antioxidant enzymes (superoxide dismutase and catalase), a reduction in lipid peroxidation, and an increase in Nrf2 expression. Moreover, brains from QTC-4-MeOBnE treated mice had a significant decrease in acetylcholinesterase activity and glycogen synthase kinase-3β levels but an increase in brain-derived neurotrophic factor and Bcl-2 expression levels. Taken together our findings demonstrate that the beneficial effect of QTC-4-MeOBnE in a mouse model of scopolamine-induced memory impairment is mediated via the involvement of different molecular pathways including oxidative stress, neuroplasticity, neuronal vulnerability, and apoptosis. Our study provides further evidence on the promising therapeutic potential of QTC-4-MeOBnE as a multifactorial disease modifying drug in AD and related dementing disorders.

Neuroprotection of SAK3 on scopolamine-induced cholinergic dysfunction in human neuroblastoma SH-SY5Y cells

Alzheimer's disease (AD) is the most common type of senile dementia. A number of factors have been proposed regarding pathology of AD, such as presence of β-amyloid, and cholinergic and oxidative stress. SAK3 (ethyl 8'-methyl-2',5-dioxo-2-piperidin-1-ylspiro[cyclopentene-3,3'-imidazo[1,2-a]pyridine]-1-carboxylate) reduces β-amyloid deposition and improves cognitive functions in amyloid precursor protein knock-in mice. Scopolamine is used to induce in cell lines a cholinergic deficit that mimics AD. In order to evaluate the possible neuroprotective properties of SAK3, human neuroblastoma SH-SY5Y cells were pretreated with the compound (25-100 nM) and further incubated in the presence of scopolamine (2 mM). SAK3 inhibited scopolamine-induced cellular apoptosis (morphologically and by determination of pro- and anti-apoptotic factor levels), increase in ROS levels, decrease in choline acetyltransferase level, phosphorylation of NF-κB, activation of Akt, JNK and p38 intracellular signaling pathways, and elevation of proinflammatory cytokines IL-1β and IL-6, but not enhanced level of β-site amyloid precursor protein cleaving enzyme 1 (BACE1). These results indicate SAK3 possessed protective properties against cholinergic deficit associated with anti-oxidant, anti-apoptotic and anti-inflammatory activities, suggesting that SAK3 might be a potential agent in the development of AD drug therapeutics.

Oral administration of hydrolyzed red ginseng extract improves learning and memory capability of scopolamine-treated C57BL/6J mice via upregulation of Nrf2-mediated antioxidant mechanism

Background

Korean ginseng (Panax ginseng Meyer) contains a variety of ginsenosides that can be metabolized to a biologically active substance, compound K. Previous research showed that compound K could be enriched in the red ginseng extract (RGE) after hydrolysis by pectinase. The current study investigated whether the enzymatically hydrolyzed red ginseng extract (HRGE) containing a notable level of compound K has cognitive improving and neuroprotective effects.

Methods

A scopolamine-induced hypomnesic mouse model was subjected to behavioral tasks, such as the Y-maze, passive avoidance, and the Morris water maze tests. After sacrificing the mice, the brains were collected, histologically examined (hematoxylin and eosin staining), and the expressions of antioxidant proteins analyzed by western blot.

Results

Behavioral assessment indicated that the oral administration of HRGE at a dosage of 300 mg/kg body weight reversed scopolamine-induced learning and memory deficits. Histological examination demonstrated that the hippocampal damage observed in scopolamine-treated mouse brains was reduced by HRGE administration. In addition, HRGE administration increased the expression of nuclear-factor-E2-related factor 2 and its downstream antioxidant enzymes NAD(P)H:quinone oxidoreductase and heme oxygenase-1 in hippocampal tissue homogenates. An in vitro assay using HT22 mouse hippocampal neuronal cells demonstrated that HRGE treatment attenuated glutamate-induced cytotoxicity by decreasing the intracellular levels of reactive oxygen species.

Conclusion

These findings suggest that HRGE administration can effectively alleviate hippocampus-mediated cognitive impairment, possibly through cytoprotective mechanisms, preventing oxidative-stress-induced neuronal cell death via the upregulation of phase 2 antioxidant molecules.

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.

Soursop fruit extract mitigates scopolamine-induced amnesia and oxidative stress via activating cholinergic and Nrf2/HO-1 pathways

Current therapeutic interventions for memory loss are inadequate and are associated with numerous adverse effects. There is an urgent need for new alternative agents for the treatment of memory loss and related disorders. Here, we investigated the potential neuroprotective role of soursop fruit extract (SSFE) in scopolamine (SCO)-induced amnesia and oxidative damage in the hippocampus of rats. Thirty-five rats were randomly allocated into 5 groups: control, SCO, SSFE, SCO, SSFE+SCO and N-acetylcysteine (NAC) + SCO. SCO-treatment increased acetylcholine esterase activity and decreased hippocampal levels of acetylcholine, serotonin, dopamine, norepinephrine, and histamine. The level of ATP increased. SCO-treated rats showed a disturbance in oxidative status, which was evident through the increase in malondialdehyde, and nitrites/nitrates and a decrease in cellular antioxidant molecules including glutathione, superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase. A disturbance was also observed via downregulation of the nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 defense pathways. SCO-treatment enhances a neuroinflammatory state, as indicated by the release of tumor necrosis factor- α and interleukin-1β and increased inducible nitric oxide synthase and mRNA expression. SCO-treatment decreased the expression of the anti-apoptotic protein, B cell lymphoma 2 and increased the expression of the pro-apoptotic protein, Bcl-2 associated X protein, caspase-3 and cytochrome c in hippocampal neurons. SSFE pretreatment markedly ameliorated hippocampal changes. Our findings revealed that SSFE exerts its potential anti-amnestic effect mainly through the activation of the cholinergic system and Nrf2/HO-1 pathway.

Neuroprotective effects of matrine on scopolamine-induced amnesia via inhibition of AChE/BuChE and oxidative stress

The present study was designed to evaluate the effects of matrine (MAT) on scopolamine (SCOP)-induced learning and memory impairment. After successive oral administration of MAT to mice for three days at doses of 0.4, 2, and 10 mg/kg, we assessed improvements in learning and memory and investigated the mechanism of action of SCOP-induced amnesia. Donepezil at a dose of 3 mg/kg was used as a standard memory enhancer. MAT significantly improved SCOP-induced learning and memory impairment in novel object recognition and Y-maze tests at doses of 0.4, 2, and 10 mg/kg. Furthermore, MAT inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activities and decreased oxidative stress in the brain, as evidenced by increased total antioxidant capacity, total superoxide dismutase levels, and catalase activities as well as decreased malondialdehyde levels. Additionally, there was a significant negative correlation between the percentage of spontaneous alternation in the Y maze and AChE activity in the cortex and hippocampus. MAT ameliorated SCOP-induced amnesia by the inhibition of both AChE/BuChE activities and oxidative stress. This study provides further evidence to encourage the development of MAT as a drug for the prevention or treatment of Alzheimer's disease.

The phosphodiesterase 5 inhibitor, KJH-1002, reverses a mouse model of amnesia by activating a cGMP/cAMP response element binding protein pathway and decreasing oxidative damage

BACKGROUND AND PURPOSE

Inhibition of PDE5 improves synaptic plasticity and memory via enhancing cGMP expression, thus activating the cGMP/cAMP response element binding protein (CREB) signalling pathway. This study investigated the effects of a PDE5 inhibitor on scopolamine-induced cognitive dysfunction, using memory-related behavioural tests and biochemical assays.

EXPERIMENTAL APPROACH

In mice were pretreated with PDE5 inhibitor, amnesia was induced by scopolamine. The learning and memory abilities of mice were tested using the Morris water maze test, the Y-maze test, the passive avoidance test and the novel object recognition test in sequence. Expression of memory-related bio-molecules and oxidative stress parameters in brain tissue were measured using Western blot and spectrophotometry respectively.

KEY RESULTS

KJH-1002, a novel and potent inhibitor of PDE5 (IC₅₀ 0.059 ± 0.04 nmol·L^-1 ), was synthesized. In the behavioural tests, it markedly improved the memory performance impaired by scopolamine, indicating a restoration of cognitive function in the mice. Moreover, KJH-1002 increased cGMP levels in the cortex and the scopolamine-reduced expression of phosphorylated CREB, Levels of ERK 1/2, Akt and brain-derived neurotrophic factor in the cortex and hippocampus were restored by KJH-1002 treatment. In addition, KJH-1002 administration increased the activities of SOD, glutathione peroxidase and glutathione reductase, and decreased the level of malondialdehyde.

CONCLUSION AND IMPLICATIONS

KJH-1002 restored cognitive function in scopolamine-induced amnesia mice by activating the cGMP/CREB signalling pathway and attenuating oxidative stress. The beneficial effects of KJH-1002 on cognition indicate its potential as a therapeutic candidate for Alzheimer's disease.

Walnut supplementation reverses the scopolamine-induced memory impairment by restoration of cholinergic function via mitigating oxidative stress in rats: a potential therapeutic intervention for age related neurodegenerative disorders

The brain is highly susceptible to the damaging effects of oxidative reactive species. The free radicals which are produced as a consequence of aerobic respiration can cause cumulative oxygen damage which may lead to age-related neurodegeneration. Scopolamine, the anti-muscarinic agent, induces amnesia and oxidative stress similar to that observed in the older age. Studies suggest that antioxidants derived from plant products may provide protection against oxidative stress. Therefore, the present study was designed to investigate the attenuation of scopolamine-induced memory impairment and oxidative stress by walnut supplementation in rats. Rats in test group were administrated with walnut suspension (400 mg/kg/day) for four weeks. Both control and walnut-treated rats were then divided into saline and scopolamine-treated groups. Rats in the scopolamine group were injected with scopolamine (0.5 mg/kg dissolved in saline) five minutes before the start of each memory test. Memory was assessed by elevated plus maze (EPM), Morris water maze (MWM), and novel object recognition task (NOR) followed by estimation of regional acetylcholine levels and acetylcholinesterase activity. In the next phase, brain oxidative status was determined by assaying lipid peroxidation, and measuring superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activities. Results showed that scopolamine-treatment impaired memory function, caused cholinergic dysfunction, and induced oxidative stress in rats compared to that saline-treated controls. These impairments were significantly restored by pre-administration of walnut. This study demonstrates that antioxidant properties of walnut may provide augmented effects on cholinergic function by reducing oxidative stress and thus improving memory performance.

Amelioration of Scopolamine-Induced Learning and Memory Impairment by α-Pinene in C57BL/6 Mice

Increasing evidence suggests that neurodegenerative disorders such as Alzheimer's disease (AD) are mediated via disruption of cholinergic neurons and enhanced oxidative stress. Therefore, attention has been focused on searching for antioxidant phytochemicals for the prevention and/or treatment of AD through their ability to fortify cholinergic function and antioxidant defense capacity. In this study, we have investigated the neuroprotective effect of α-pinene (APN) against learning and memory impairment induced by scopolamine (SCO, 1 mg/kg, i.p.), a muscarinic receptor antagonist in C57BL/6 mice. Administration of APN (10 mg/kg, i.p.) significantly improved SCO-induced cognitive dysfunction as assessed by Y-maze and passive avoidance tests. In Morris water-maze test, APN effectively shortened the mean escape latency to find the hidden platform during training days. To further elucidate the molecular mechanisms underlying the neuroprotective effect of APN, the expression of proteins involved in the acetylcholine metabolism and antioxidant system was examined. Particularly, APN treatment increased mRNA expression of choline acetyltransferase in the cortex and protein levels of antioxidant enzymes such as heme oxygenase-1 and manganese superoxide dismutase in the hippocampus via activation of NF-E2-related factor 2. These findings suggest the possible neuroprotective potentials of APN for the management of dementia with learning and memory loss.

Lycium barbarum polysaccharide protects against neurotoxicity via the Nrf2-HO-1 pathway

The incidence of neurodegenerative diseases including Alzheimer's and Parkinson's disease has markedly increased over the past few decades. Oxidative stress is considered to be a common pathophysiological condition resulting in neurotoxicity. Lycium barbarum polysaccharide (LBP) is the major active component of Lycium barbarum L., which exhibit potent antioxidant activity. The current study investigated the neuroprotective effects of LBP in H₂O₂-treated PC12 cells in vitro and in CoCl₂-treated rats in vivo. It was determined that LBP concentration-dependently reversed the H₂O₂-induced increase in reactive oxygen species (ROS) levels, decrease in cell viability, increase in TUNEL-stained cells, increase in caspase-3 and −9 activity and decrease in mitochondrial membrane potential, indicating the amelioration of mitochondrial apoptosis. Furthermore, LBP inhibited the H₂O₂-induced decrease in nuclear factor erythroid 2-related factor 2 (Nrf)2 and heme oxygenase (HO)-1 expression and binding of Nrf2 to the promoters of HO-1. Silencing of Nrf2 and inhibition of HO-1 by zinc protoporphyrin IX (ZnPP) reversed the protective effects of LBP against H₂O₂-resulted neurotoxicity in PC12 cells. In CoCl₂-treated rats, it was demonstrated that LBP decreased brain tissue apoptosis, reduced the time spent by rats finding the platform site, decreased escape latencies and reduced the distance traveled to find the platform. In addition, LBP inhibited the CoCl₂-induced decrease of Nrf2 and HO-1 expression. Administration of ZnPP also suppressed the protective effects of LBP against CoCl₂-resulted neurotoxicity in rats. Thus, the current study indicated that LBP exhibits protective effects against neurotoxicity by upregulating Nrf2/HO-1 signaling. These data may increase understanding regarding the neuroprotective activities of LBP.

Ethyl Acetate Extract Components of Bushen-Yizhi Formula Provides Neuroprotection against Scopolamine-induced Cognitive Impairment

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder and there is no effective cure for this devastating disease to date. Bushen Yizhi Formula (BSYZ-F), a Chinese herbal compound, has proved to be effective for AD. In this study, we further investigate the effective part of BSYZ-F, ethyl acetate extract components of BSYZ-F (BSYZ-E), protects scopolamine (SCOP)-induced cognitive impairment, which shows a similar effect to BSYZ-F. We also find that BSYZ-E could protect against SCOP-induced cholinergic system dysfunction. In neuron function level, BSYZ-E remarkably elevates protein levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). BSYZ-E also significantly mitigates SCOP-induced apoptosis, oxidative stress and nitrosative stress. Conclusively, BSYZ-E, the effective part of BSYZ-F, can provide neuroprotection against SCOP-induced cognitive impairment through a multifunctional strategy. These findings suggest that BSYZ-E might be developed as a therapeutic drug for AD by targeting multiple pathways of the pathogenesis.

Mitochondrial involvement in memory impairment induced by scopolamine in rats

OBJECTIVE

Scopolamine (SCO) administration to rats induces molecular features of AD and other dementias, including impaired cognition, increased oxidative stress, and imbalanced cholinergic transmission. Although mitochondrial dysfunction is involved in different types of dementias, its role in cognitive impairment induced by SCO has not been well elucidated. The aim of this work was to evaluate the in vivo effect of SCO on different brain mitochondrial parameters in rats to explore its neurotoxic mechanisms of action.

METHODS

Saline (Control) or SCO (1 mg/kg) was administered intraperitoneally 30 min prior to neurobehavioral and biochemical evaluations. Novel object recognition and Y-maze paradigms were used to evaluate the impact on memory, while redox profiles in different brain regions and the acetylcholinesterase (AChE) activity of the whole brain were assessed to elucidate the amnesic mechanism of SCO. Finally, the effects of SCO on brain mitochondria were evaluated both ex vivo and in vitro, the latter to determine whether SCO could directly interfere with mitochondrial function.

RESULTS

SCO administration induced memory deficit, increased oxidative stress, and increased AChE activities in the hippocampus and prefrontal cortex. Isolated brain mitochondria from rats administered with SCO were more vulnerable to mitochondrial swelling, membrane potential dissipation, H₂O₂ generation and calcium efflux, all likely resulting from oxidative damage. The in vitro mitochondrial assays suggest that SCO did not affect the organelle function directly.

CONCLUSION

In conclusion, the present results indicate that SCO induced cognitive dysfunction and oxidative stress may involve brain mitochondrial impairment, an important target for new neuroprotective compounds against AD and other dementias.

Neuroprotection of N-benzylcinnamide on scopolamine-induced cholinergic dysfunction in human SH-SY5Y neuroblastoma cells

Alzheimer's disease, a progressive neurodegenerative disease, affects learning and memory resulting from cholinergic dysfunction. Scopolamine has been employed to induce Alzheimer's disease-like pathology in vivo and in vitro through alteration of cholinergic system. N-benzylcinnamide (PT-3), purified from Piper submultinerve, has been shown to exhibit neuroprotective properties against amyloid-β-induced neuronal toxicity in rat cortical primary cell culture and to improve spatial learning and memory of aged rats through alleviating oxidative stress. We proposed a hypothesis that PT3 has a neuroprotective effect against scopolamine-induced cholinergic dysfunction. PT-3 (125–200 nM) pretreatment was performed in human neuroblastoma SH-SY5Y cell line following scopolamine induction. PT-3 (125–200 nM) inhibited scopolamine (2 mM)-induced generation of reactive oxygen species, cellular apoptosis, upregulation of acetylcholinesterase activity, downregulation of choline acetyltransferase level, and activation of p38 and JNK signalling pathways. These findings revealed the underlying mechanisms of scopolamine-induced Alzheimer's disease-like cellular dysfunctions, which provide evidence for developing drugs for the treatment of this debilitating disease.