Cognitive-enhancing and antioxidant activities of iridoid glycosides from Scrophularia buergeriana in scopolamine-treated mice

An Integrative Study of Scrophularia takesimensis Nakai in an Ovalbumin-Induced Murine Model of Asthma: The Effect on T Helper 2 Cell Activation

Scrophularia have traditionally been used as herbal medicines to treat neuritis, sore throats, and laryngitis. In particular, S. takesimensis, a Korean endemic species with restricted distribution on Ulleung Island, holds significant resource and genetic value. However, its pharmacological properties have not been thoroughly evaluated. Thus, we provide detailed morphological characteristics and genomic information for S. takesimensis in this study. Moreover, its pharmacological activity was evaluated in an ovalbumin-induced asthma rat model, using extracts of S. takesimensis roots (100 or 200 mg/kg). The distinguishing features of S. takesimensis from related species include the presence or absence of stem wings, leaf shape, and habitat. The chloroplast (cp) genome of this species is 152,420 bp long and exhibits a conserved quadripartite structure. A total of 114 genes were identified, which included 80 protein-coding genes, 30 transfer RNA (tRNA) genes, and 4 ribosomal RNA (rRNA) genes. The gene order, content, and orientation of the S. takesimensis cp genome was highly conserved and consistent with the general structure observed in S. buergeriana and S. ningpoensis cp genomes. Confirming the anti-inflammatory effects of S. takesimensis extract (STE) using an established mouse model of ovalbumin-induced asthma, we observed reduced asthmatic phenotypes, including inflammatory cell infiltration, mucus production, and suppression of T helper 2 (Th2) cell. Furthermore, STE treatment reduced Th2 cell activation and differentiation. This study underscores the medicinal value of S. takesimensis. The importance of preserving S. takesimensis was revealed and crucial insights were provided for further research on its utilization as a medicinal resource.

The Potential Neuroprotective Effect of Thymoquinone on Scopolamine-Induced In Vivo Alzheimer's Disease-like Condition: Mechanistic Insights

BACKGROUND

Alzheimer's disease (AD) is a common neurodegenerative disorder without effective treatment. Thymoquinone (TQ) has demonstrated potential in exhibiting anti-inflammatory, anti-cancer, and antioxidant characteristics. Despite TQ's neuroprotection effect, there is a scarcity of information regarding its application in AD research, and its molecular trajectories remain ambiguous. Thus, the objective of the current investigation was to examine the potential beneficial effects and underlying mechanisms of TQ in scopolamine (SCOP)-induced neuronal injury to mimic AD in vivo model.

METHODS

Thirty mice were divided into normal, SCOP, and TQ groups. The Y-maze and pole climbing tests were performed to measure memory and motor performance. Afterwards, histopathological and immunohistochemical examinations were carried out. Furthermore, peroxisome proliferator-activated receptor gamma (PPAR-γ) signaling pathway-related proteins and genes were detected with an emphasis on the role of miR-9.

RESULTS

TQ has the potential to ameliorate cognitive deficits observed in SCOP-induced AD-like model, as evidenced by the improvement in behavioral outcomes, histopathological changes, modulation of the expression pattern of PPAR-γ downstream targets with a significant decrease in the deposition of amyloid beta (Aβ).

CONCLUSIONS

TQ provided meaningful multilevel neuroprotection through its anti-inflammatory and its PPAR-γ agonist activity. Consequently, TQ may possess a potential beneficial role against AD development.

The effect of the calcium channel blocker nimodipine on hippocampal BDNF/Ach levels in rats with experimental cognitive impairment

OBJECTIVE

Alzheimer's disease (AD) occurs in approximately 10% to 30% of individuals aged 65 or older worldwide. Novel therapeutic agents therefore need to be discovered in addition to traditional medications. Nimodipine appears to possess the potential to reverse cognitive impairment-induced dysfunction in learning and memory through its regulatory effect on the brain-derived neurotrophic factor (BDNF), acetylcholine (Ach), and acetylcholinesterase (AChE) pathway in the hippocampus and prefrontal cortex.

METHODS

Twenty-four male Sprague Dawley rats weighing 380 ± 10 g were used for behavioral and biochemical analyses. These were randomly and equally assigned into one of three groups. Group 1 received saline solution alone via the intraperitoneal (i.p) route, and Group 2 received 1 mg/kg/day i.p. scopolamine once a day for three weeks for induction of learning and memory impairments. In Group 3, 10 mg/kg/day nimodipine was prepared in tap water and administered orally every day for three weeks, followed after 30 min by 1 mg/kg/day scopolamine i.p. Behavior was evaluated using the Morris Water Maze test. BDNF, ACh, and AChE levels were determined using the ELISA test in line with the manufacturer's instructions.

RESULTS

Nimodipine treatment significantly increased the time spent in the target quadrant and the number of entries into the target quadrant compared to the scopolamine group alone. Additionally, BDNF and ACh levels in the hippocampus and prefrontal cortex decreased following 20-day scopolamine administration, while AChE activation increased.

CONCLUSION

Nimodipine exhibited potentially beneficial effects by ameliorating cognitive decline following scopolamine administration in the hippocampus and prefrontal cortex.

The effect of curcumin on blood pressure and cognitive impairment in spontaneously hypertensive rats

BACKGROUND/OBJECTIVES

It is known that the renin-angiotensin system (RAS) in the brain could regulate cognitive functions as well as blood pressure. Inhibition of RAS for the improvement of cognitive function may be a new strategy, but studies so far have mostly reported on the effects of RAS inhibition by drugs, and there is no research on cognitive improvement through RAS inhibition of food ingredients. Therefore, this study investigated the effect of curcumin on blood pressure and cognitive function and its related mechanism in spontaneously hypertensive rat/Izm (SHR/Izm).

MATERIALS/METHODS

Six-week-old SHR/Izm rats were divided into 5 groups: control group (CON), scopolamine group (SCO, drug for inducing cognitive deficits), positive control (SCO and tacrine [TAC]), curcumin 100 group (CUR100, SCO + Cur 100 mg/kg), and curcumin 200 group (CUR200, SCO + Cur 200 mg/kg). Changes in blood pressure, RAS, cholinergic system, and cognitive function were compared before and after cognitive impairment.

RESULTS

The SCO group showed increased blood pressure and significantly reduced cognitive function based on the y-maze and passive avoidance test. Curcumin treatments significantly improved blood pressure and cognitive function compared with the SCO group. In both the CUR100 and CUR200 groups, the mRNA expressions of angiotensin-converting enzyme (ACE) and angiotensin II receptor type1 (AT1), as well as the concentrations of angiotensin II (Ang II) in brain tissue were significantly decreased. The mRNA expression of the muscarinic acetylcholine receptors (mAChRs) and acetylcholine (ACh) content was significantly increased, compared with the SCO group.

CONCLUSIONS

The administration of curcumin improved blood pressure and cognitive function in SCO-induced hypertensive mice, indicating that the cholinergic system was improved by suppressing RAS and AT1 receptor expression and increasing the mAChR expression.

New Myrtenal–Adamantane Conjugates Alleviate Alzheimer’s-Type Dementia in Rat Model

Alzheimer’s disease (AD) is a neurodegenerative disease associated with memory impairment and other central nervous system (CNS) symptoms. Two myrtenal–adamantane conjugates (MACs) showed excellent CNS potential against Alzheimer’s models. Adamantane is a common pharmacophore for drug design, and myrtenal (M) demonstrated neuroprotective effects in our previous studies. The aim of this study is to evaluate the MACs’ neuroprotective properties in dementia. Methods: Scopolamine (Scop) was applied intraperitoneally in Wistar rats for 11 days, simultaneously with MACs or M as a referent, respectively. Brain acetylcholine esterase (AChE) activity, noradrenaline and serotonin levels, and oxidative brain status determination followed behavioral tests on memory abilities. Molecular descriptors and docking analyses for AChE activity center affinity were performed. Results: M derivatives have favorable physicochemical parameters to enter the CNS. Both MACs restored memory damaged by Scop, showing significant AChE-inhibitory activity in the cortex, in contrast to M, supported by the modeling analysis. Moderate antioxidant properties were manifested by glutathione elevation and catalase activity modulation. MACs also altered noradrenaline and serotonin content in the hippocampus. Conclusion: For the first time, neuroprotective properties of two MACs in a rat dementia model were observed. They were stronger than the natural M effects, which makes the substances promising candidates for AD treatment.

4-Methoxycinnamic acid attenuates schizophrenia-like behaviors induced by MK-801 in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Scrophularia buergeriana has been used for traditional medicine as an agent for reducing heat in the blood and for nourishing kidney 'Yin'. Therefore, S. buergeriana might be a potential treatment for mental illness, especially schizophrenia, which may be attenuated by supplying kidney Yin and reducing blood heat. In a pilot study, we found that S. buergeriana alleviated sensorimotor gating dysfunction induced by MK-801.

AIM OF THE STUDY

In the present study, we attempted to reveal the active component(s) of S. buergeriana as a candidate for treating sensorimotor gating dysfunction, and we identified 4-methoxycinnamic acid. We explored whether 4-methoxycinnamic acid could affect schizophrenia-like behaviors induced by hypofunction of the glutamatergic neurotransmitter system.

MATERIALS AND METHODS

Mice were treated with 4-methoxycinnamic acid (3, 10, or 30 mg/kg, i.g.) under MK-801-induced schizophrenia-like conditions. The effect of 4-methoxycinnamic acid on schizophrenia-like behaviors were explored using several behavioral tasks. We also used Western blotting to investigate which signaling pathway(s) is involved in the pharmacological activities of 4-methoxycinnamic acid.

RESULTS

4-Methoxycinnamic acid ameliorated MK-801-induced prepulse inhibition deficits, social interaction disorders and cognitive impairment by regulating the phosphorylation levels of PI3K, Akt and GSK-3β signaling in the prefrontal cortex. And there were no adverse effects in terms of catalepsy and motor coordination impairments.

CONCLUSION

Collectively, 4-methoxycinnamic acid would be a potential candidate for treating schizophrenia with fewer adverse effects, especially the negative symptoms and cognitive dysfunctions.

Neuroprotective Effects of Myrtenal in an Experimental Model of Dementia Induced in Rats

There is growing attention on natural substances capable of stimulating the cholinergic system and of exerting antioxidant effects, as potential therapeutic agents in Alzheimer’s disease (AD). The aim of the present study is to evaluate the expected neuroprotective mechanisms of myrtenal (M) in an experimental model of dementia in rats. Dementia was induced in male Wistar rats by scopolamine (Sc) administration (0.1 mg/kg for 8 days and 20.0 mg/kg on day 9). The animals were divided into 5 groups (1) Controls; (2) Sc; (3) Sc + Myrtenal (40 mg/kg), (4) Sc + Galantamine (1 mg/kg); (5) Sc + Lipoic acid (30 mg/kg). Changes in recognition memory and habituation were evaluated via the Novel Object Recognition and Open Field tests. Acetylcholinesterase (AChE) activity, ACh levels, and changes in oxidative status of the brain were measured biochemically. The histological changes in two brain regions—cortex and hippocampus, were evaluated qualitatively and quantitatively. Myrtenal improved recognition memory and habituation, exerted antioxidant effects and significantly increased ACh brain levels. Histologically, the neuroprotective capacity of myrtenal was also confirmed. For the first time, we have demonstrated the neuroprotective potential of myrtenal in an experimental model of dementia. Our study provides proof-of-concept for the testing of myrtenal, in association with standard of care treatments, in patients affected by cognitive decline.

Sea Cucumber-Derived Peptide Attenuates Scopolamine-Induced Cognitive Impairment by Preventing Hippocampal Cholinergic Dysfunction and Neuronal Cell Death

The incidence of neurodegenerative diseases related to cognitive decline and memory loss is on the rise as the global elderly population increases. In this study, we evaluated the effect of the sea cucumber-derived peptide Phe-Tyr-Asp-Trp-Pro-Lys (FYDWPK) on scopolamine-induced neurotoxicity in an animal model. The Morris water maze, passive avoidance apparatus, and shuttle box test were used to assess learning and memory abilities. In behavioral tests, FYDWPK effectively alleviated learning and memory impairment. FYDWPK also alleviated cholinergic dysfunction in mice with dementia. Furthermore, FYDWPK significantly improved oxidative imbalance by increasing superoxide dismutase activity and decreasing malondialdehyde levels (P < 0.05). The pathological results showed that FYDWPK alleviated neuronal loss, blurred caryotheca, and pyknotic nuclei in the hippocampus, and a high dose of FYDWPK had the best effect. In conclusion, FYDWPK alleviated cognitive and memory impairments by regulating oxidative imbalance, reducing cholinergic dysfunction, and relieving pathological alterations.

Effects of New Galantamine Derivatives in a Scopolamine Model of Dementia in Mice

Alzheimer's disease (AD), a progressive neurodegenerative disorder characterized by memory loss and cognitive functions decline, is a leading cause for dementia and currently ranked as the sixth foremost cause of death. As of present, treatment of AD is symptomatic without convincing therapeutic benefits and new, effective, therapeutic agents are pursued. Due to massive loss of cholinergic neurons and decreased acetylcholine levels, cholinesterase inhibitors like galantamine, remain the backbone of pharmacological treatment of the disease. In the present study, using behavioral and biochemical methods, four newly synthesized galantamine derivatives, Gal 34, Gal 43, Gal 44, and Gal 46, were evaluated for a beneficial effect in a scopolamine model of dementia in mice. They were designed to have all the advantages of galantamine and additionally to inhibit β-secretase and exert favorable effects on plasma lipids. Behavioral tests included step-through inhibitory avoidance, T-maze, and the hole-board test, whereas biochemical evaluations involved assessment of acetylcholinesterase activity, brain monoamines levels, lipid peroxidation, catalase, glutathione peroxidase, and superoxide dismutase activities along with measurement of total glutathione. Results show that Gal 43, Gal 44, and, in particular, Gal 46 are especially effective in improving both short- and long-term memory and in the case of Gal 46 having a significant effect on exploratory activity as well. Although Gal 34 did not show behavioral effects as convincing as those of the other three galantamine derivatives, it demonstrated persuasive antioxidant and restorative capacities, making all four galantamine derivatives promising AD treatment agents and prompting further research, especially that in many of our studies they performed better than galantamine.

Apigenin Ameliorates Scopolamine-Induced Cognitive Dysfunction and Neuronal Damage in Mice

We investigated the protective effect and mechanisms of apigenin against cognitive impairments in a scopolamine-injected mouse model. Our results showed that intraperitoneal (i.p.) injection of scopolamine leads to learning and memory dysfunction, whereas the administration of apigenin (synthetic compound, 100 and 200 mg/kg/day) improved cognitive ability, which was confirmed by behavioral tests such as the T-maze test, novel objective recognition test, and Morris water maze test in mice. In addition, scopolamine-induced lipid peroxidation in the brain was attenuated by administration of apigenin. To further evaluate the protective mechanisms of apigenin on cognitive and memory function, Western blot analysis was carried out. Administration of apigenin decreased the B-cell lymphoma 2-associated X/B-cell lymphoma 2 (Bax/Bcl-2) ratio and suppressed caspase-3 and poly ADP ribose polymerase cleavage. Furthermore, apigenin down-regulated the β-site amyloid precursor protein-cleaving enzyme, along with presenilin 1 (PS1) and PS2 protein levels. Apigenin-administered mice showed lower protein levels of a receptor for advanced glycation end-products, whereas insulin-degrading enzyme, brain-derived neurotrophic factor (BDNF), and tropomyosin receptor kinase B (TrkB) expression were promoted by treatment with apigenin. Therefore, this study demonstrated that apigenin is an active substance that can improve cognitive and memory functions by regulating apoptosis, amyloidogenesis, and BDNF/TrkB signaling pathways.

Changes in the Harpagide, Harpagoside, and Verbascoside Content of Field Grown Scrophularia lanceolata and Scrophularia marilandica in Response to Season and Shade

Scrophularia lanceolata Pursh and Scrophularia marilandica L. are two common species within the Scrophulariaceae family that are endemic to North America. Historically, these species were used by indigenous peoples and colonialists to treat sunburn, sunstroke, frostbite, edema, as well as for blood purification, and in women's health. Several iridoid and phenylethanoid/phenylpropanoid glycosides detected in these species, such as harpagoside and verbascoside, possess anti-inflammatory and anti-nociceptive properties. Due to the presence of anti-inflammatory metabolites and the historical uses of these species, we performed a two-year field study to determine the optimal production of these important compounds. We subjected the plants to shade treatment and analyzed differences in the metabolite composition between the two species and each of their leaves, stems, and roots at various times throughout the growing seasons. We determined that S. lanceolata plants grown in full sun produced 0.63% harpagoside per dried weight in their leaves compared to shade-grown plants (0.43%). Furthermore, S. lanceolata accumulated more harpagoside than S. marilandica (0.24%). We also found that verbascoside accumulated in the leaves of S. lanceolata and S. marilandica as the growing season progressed, while the production of this metabolite remained mostly seasonally unchanged in the roots of both species.

Does the application of acetylcholinesterase inhibitors in the treatment of Alzheimer's disease lead to depression?

Introduction: Alzheimer's disease and depression are health conditions affecting millions of people around the world. Both are strongly related to the level of the neurotransmitter acetylcholine. Since cholinergic deficit is characteristic of Alzheimer's disease, acetylcholinesterase inhibitors are applied as relevant drugs for the treatment of this disease, elevating the level of acetylcholine. On the other hand, a high level of acetylcholine is found to be associated with the symptoms of clinical depression.Areas covered: This article aims to discuss if acetylcholinesterase inhibitors used as anti-Alzheimer's drugs could be the cause of the symptoms of clinical depression often linked to this neurological disorder. Emphasis will be put on drugs currently in use and on newly investigated natural products, which can inhibit AChE activity.Expert opinion: Currently, it is not proven that the patient treated for Alzheimer's disease is prone to increased risk for depression due to the acetylcholinesterase inhibition, but there are strong indications. The level of acetylcholine is not the only factor in highly complicated diseases like AD and depression. Still, it needs to be considered isolated, keeping in mind the nature of presently available therapy, especially during a rational drug design process.

Neuroprotective Effect and Antioxidant Potency of Fermented Cultured Wild Ginseng Root Extracts of Panax ginseng C.A. Meyer in Mice

Wild ginseng has better pharmacological effects than cultivated ginseng. However, its industrialization is limited by the inability to grow wild ginseng on a large scale. Herein, we demonstrate how to optimize ginseng production through cultivation, and how to enhance the concentrations of specific ginsenosides through fermentation. In the study, we also evaluated the ability of fermented cultured wild ginseng root extract (HLJG0701-β) to inhibit acetylcholinesterase (AChE), as well as its neuroprotective effects and antioxidant activity. In invitro tests, HLJG0701-β inhibited AChE activity and exerted neuroprotective and antioxidant effects (showing increased catalyst activity but decreased reactive oxygen species concentration). In invivo tests, after HLJG0701-β was orally administered at doses of 0, 125, 250, and 500 mg/kg in an animal model of memory impairment, behavioral evaluation (Morris water maze test and Y-maze task test) was performed. The levels of AChE, acetylcholine (ACh), blood catalase (CAT), and malondialdehyde (MDA) in brain tissues were measured. The results showed that HLJG0701-β produced the best results at a dose of 250 mg/kg or more. The neuroprotective mechanism of HLJG0701-β was determined to involve the inhibition of AChE activity and a decrease in oxidative stress. In summary, both invitro and invivo tests confirmed that HJG0701-β administration can lead to memory improvement.

Pharmacology, phytochemistry, and traditional uses of Scrophularia ningpoensis Hemsl

ETHNOPHARMACOLOGICAL RELEVANCE

Scrophularia ningpoensis Hemsl. (known as Xuanshen) has been used in China for centuries as a traditional medicinal plant to treat numerous diseases including inflammation, hypertension, cancer, and diabetes.

AIM OF REVIEW

In this review, we provide an update on the botany, pharmacology, phytochemistry, pharmacokinetics, traditional uses, and safety of S. ningpoensis to highlight future research needs and potential uses of this plant.

MATERIALS AND METHODS

All information on S. ningpoensis was obtained from scientific databases including ScienceDirect, Springer, PubMed, Sci Finder, China Knowledge Resource Integrated Database from the China National Knowledge Infrastructure (CNKI), Google Scholar, and Baidu Scholar. Additional information was collected from Chinese herbal medicine books, Ph.D. dissertations, and M.Sc. Theses. Plant taxonomy was verified by "The Plant List" database (http://www.theplantlist.org).

RESULTS

S. ningpoensis displays fever reducing, detoxifying, and nourishing 'Yin' effects in traditional Chinese medicine (TCM). More than 162 compounds have been identified and isolated from S. ningpoensis, including iridoids and iridoid glycosides, phenylpropanoid glycosides, organic acids, volatile oils, terpenoids, saccharides, flavonoids, sterols, and saponins. These compounds possess a diverse variety of pharmacological properties that affect the cardiovascular, hepatic, and nervous systems, and protect the body against inflammation, oxidation, and carcinogenesis.

CONCLUSIONS

Modern pharmacological studies have confirmed that S. ningpoensis is a valuable Chinese medicinal herb with many pharmacological uses in the treatment of cardiovascular, diabetic, and liver diseases. Most of the S. ningpoensis activity may be attributed to iridoid glycosides and phenylpropanoid glycosides; however, detailed information on the molecular mechanisms, metabolic activity, toxicology, and structure-function relationships of active components is limited. Further comprehensive research to evaluate the medicinal properties of S. ningpoensis is needed.

Lacidipine Prevents Scopolamine-Induced Memory Impairment by Reducing Brain Oxido-nitrosative Stress in Mice

Cholinergic deficits and oxido-nitrosative stress are consistently associated with Alzheimer's disease (AD). Previous findings indicate that acetylcholine subdues Ca²⁺ current in the brain. Cholinergic antagonists (e.g., scopolamine) can instigate Ca²⁺-induced redox imbalance, inflammation, and cell-death pathways leading to AD-type memory impairment. Earlier, several Ca²⁺-channel blockers (CCB, e.g., dihydropyridine type) or cholinergic enhancers showed promising results in animal models of AD. In the present research, pretreatment effects of lacidipine (L-type CCB) on learning and memory functions were investigated using the scopolamine mouse model of AD. Swiss albino mice (20-25 g) were administered lacidipine (1 and 3 mg/kg) for 14 days. Scopolamine, an anti-muscarinic drug, was given (1 mg/kg) from days 8 to 14. The mice were subjected to elevated plus maze (EPM) and passive-avoidance (PA) paradigms. Bay-K8644 (a Ca²⁺-channel agonist) was administered before behavioral studies on days 13 and 14. Biochemical parameters of oxidative stress and acetylcholinesterase (AChE) activity were quantified using the whole brain. Behavioral studies showed an increase in transfer latency (TL) in the EPM test and a decrease in step-through latency (STL) in the PA test in scopolamine-administered mice. Scopolamine enhanced the AChE activity and oxidative stress in the brain of mice which resulted in memory impairment. Lacidipine prevented the amnesia against scopolamine and reduced the oxidative stress and AChE activity in the brain of mice. Bay-K8644 attenuated the lacidipine-induced improvement in memory and redox balance in scopolamine-administered mice. Lacidipine can prevent the oxidative stress and improve the cholinergic function in the brain. These properties of lacidipine can mitigate the pathogenesis of AD-type dementia.

8-O-(E-p-methoxycinnamoyl)harpagide Inhibits Influenza A Virus Infection by Suppressing Intracellular Calcium

Calcium (Ca²⁺) dependent signaling circuit plays a critical role in influenza A virus (IAV) infection. The 8-O-(E-p-methoxycinnamoyl)harpagide (MCH) exhibits pharmacological activities that exert neuroprotective, hepatoprotective, anti-inflammatory and other biological effects. However, not have reports of antiviral effects. To investigate the antiviral activity of MCH on IAV-infected human lung cells mediated by calcium regulation. We examined the inhibitory effect of MCH on IAV infections and measured the level of viral proteins upon MCH treatment using Western blotting. We also performed molecular docking simulation with MCH and IAV M2 protein. Finally, we analyzed MCH’s suppression of intracellular calcium and ROS (reactive oxygen species) in IAV-infected human lung cells using a flow cytometer. The results shown that MCH inhibited the infection of IAV and increased the survival of the infected human lung cells. The levels of IAV protein M1, M2, NS1 and PA were inhibited in MCH-treated human lung cells compared to that in infected and untreated cells. Also, docking simulation suggest that MCH interacted with M2 on its hydrophobic wall (L40 and I42) and polar amino acids (D44 and R45), which formed intermolecular contacts and were a crucial part of the channel gate along with W41. Lastly, MCH inhibited IAV infection by reducing intracellular calcium and mitochondrial Ca²⁺/ROS levels in infected human lung cells. Taken together, these data suggest that MCH inhibits IAV infection and increases the survival of infected human lung cells by suppressing calcium levels. These results indicate that MCH is useful for developing IAV treatments.

Neuroprotective effects of the aerial parts of Polygala tenuifolia Willd extract on scopolamine-induced learning and memory impairments in mice

Alzheimer's disease is a common neurodegenerative disease characterized by progressive cognitive dysfunction and behavioral impairment. Aerial parts of Polygala tenuifolia Willd (APT) is a traditional Chinese medicine used for the treatment of amnesia. The present study aimed to investigate the protective effects of APT on scopolamine-induced learning and memory impairments in mice. Scopolamine-induced mice were used to determine the effects of APT on learning and memory impairment. Mice were orally administered with APT (25, 50 and 100 mg/kg) and piracetam (750 mg/kg) for 14 days, and intraperitoneally injected with scopolamine (2 mg/kg) from days 8 to 14. Morris water maze and step-down tests were performed to evaluate learning and memory. Levels of acetylcholine (ACh), choline acetyltransferase (ChAT), acetylcholinesterase (AChE), interleukin (IL)-1β, IL-10 and brain-derived neurotrophic factor (BDNF) in the hippocampus and frontal cortex were measured by ELISA. Superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) were measured via biochemical detection. The results demonstrated that APT ameliorated learning and memory impairment in scopolamine-induced mice. Correspondingly, APT significantly increased ACh and ChAT levels in the hippocampus and prefrontal cortex of scopolamine-induced mice. Additionally, treatment with APT significantly increased BDNF and IL-10 levels, and decreased IL-1β and AChE levels in the same mice. Furthermore, APT significantly increased SOD activity and GSH content, and decreased MDA levels in brain tissue. These results indicated that APT may ameliorate learning and memory impairment by regulating cholinergic activity, promoting BDNF and inhibiting neuroinflammation and oxidative stress.

Neuroprotective Function of a Novel Hexapeptide QMDDQ from Shrimp via Activation of the PKA/CREB/BNDF Signaling Pathway and Its Structure-Activity Relationship

This study aimed to evaluate the neuroprotective function of shrimp-derived peptides QMDDQ and KMDDQ. Biochemical results revealed that both peptides exhibited neuroprotective effects by increasing acetylcholine (ACh) content and inhibiting acetylcholinesterase (AChE) activity in PC12 cells; QMDDQ was more active than KMDDQ. COSY-NOESY spectroscopic data showed that the superior neuroprotective function of QMDDQ might be attributed to its N-terminal glutamine as it exhibited an extended spatial conformation, facilitating its interactions with AChE. QMDDQ can promote the basic energy metabolism of cells more than KMDDQ. The peptides showed neuroprotective ability due to the activation of the antiapoptosis and PKA/CREB/BNDF signaling pathway. QMDDQ was selected to investigate its memory-enhancing activity in scopolamine-induced amnesic mice, revealing memory protection in mice, as it improved their performance in the Morris water maze experiment. In addition, QMDDQ increased ACh content (4.98 ± 0.51 μg/mg prot) and decreased AChE activity (4.72 ± 0.11 U/mg prot) in the mouse hippocampus. These data indicate the systemic mechanism through which naturally derived QMDDQ improved neuroprotection and memory ability.

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.

Scrophularia Tenuipes Coss and Durieu: Phytochemical Composition and Biological Activities

Scrophularia tenuipes is an Algerian-Tunisian endemic species, which has not been studied yet. Ethyl acetate (EA) and n-butanol (Bu) fractions obtained from Scrophularia tenuipes were investigated for their health benefit properties, in particular with respect to in vivo/in vitro anti-inflammatory and antioxidant activities, as well as their potential to inhibit key enzymes with impact in diabetes (α-glucosidase and α-amylase). The fractions had a distinct phytochemical composition, of which EA was richer in total phenolic compounds (225 mg GAE/g) and mostly composed of the phenylethanoid acetyl martynoside. Compared to EA, Bu had higher amounts of total flavonoids, and according to the result obtained from UHPLC-DAD-ESI-MSn analysis, harpagoside (iridoid) was its major phytochemical. EA fraction was quite promising with regard to the in vivo (at 200 mg/kg, po) anti-inflammatory effect (62% and 52% for carrageenan-induced rat paw edema and xylene-induced ear edema tests, respectively), while Bu fraction exhibited a stronger antioxidant capacity in all tests (IC50 = 68 µg/mL, IC50 = 18 µg/mL, IC50 = 18 µg/mL and A0.50 = 43 µg/mL for DPPH●, ABTS•+, O2•- scavenging assays and cupric-reducing antioxidant capacity method, respectively). Both fractions also showed a strong effect against α-amylase enzyme (IC50 = 8 µg/mL and 10 µg/mL for EA and Bu fraction, respectively).

In Vivo Cognitive-Enhancing, Ex Vivo Malondialdehyde-Lowering Activities and Phytochemical Profiles of Aqueous and Methanolic Stem Bark Extracts of Piliostigma thonningii (Schum.)

Cognitive impairment (CI) is among the leading causes of disability in humans. It is estimated that over 35.6 million people are suffering from Alzheimer's disease- (AD-) associated cognitive deficits globally with these statistics projected to rise over 115.4 million by the year 2050. There is no specific etiology for this cognitive impairment; however, various contributing factors including advancing age (>60 years old), oxidative stress, cerebral injuries, infections, neurologic disorders, and cancer have been implicated. Despite various attempts to manage CI, no curative medicines are yet available. The current drugs used to manage symptoms of AD-associated CI including Donepezil and Rivastigmine among others are only palliative rather than therapeutic. Furthermore, these agents have been associated with undesirable side effects. This calls for alternative and complementary approaches aimed at either preventing or reverting AD-related CI in a curative way without causing adverse events. It is estimated that over 80% of the world's population utilize herbal medicines for basic healthcare as it is considered safe, affordable, and easily accessible as opposed to conventional healthcare. Various parts of P. thonningii are used in traditional medicine to manage various conditions including CI. However, empirical and scientific data to validate these uses is lacking. In this study, the Morris water maze (MWM) experiment was adopted to evaluate the cognitive-enhancing effects of the studied plant extracts. The malondialdehyde (MDA) profiles in the brains of experimental mice were determined using the thiobarbituric acid reactive substances (TBARS) test. Moreover, qualitative phytochemical profiling of the studied plant extracts was performed using standard procedures. The results showed remarkable cognitive-enhancing activities which were reflected in significantly shorter transfer latencies, navigation distances, longer time spent in platform quadrant, and lower MDA levels compared with those recorded for the negative control mice (p < 0.05). Phytochemical screening of the studied plant extracts revealed the presence of antioxidant phytocompounds, which may have played key roles in the extracts' potency. Based on the findings herein, P. thonningii extracts, especially the aqueous ones have a promising potential for the management of AD-associated CI. Further studies aimed at isolating and characterizing specific active compounds for CI from P. thonningii are recommended. Additionally, specific mode(s) of action of active principles should be elucidated. Moreover, toxicity studies should be done on the studied plant extracts to ascertain their safety.

Scrophularia buergeriana attenuates allergic inflammation by reducing NF-κB activation

BACKGROUND

Scrophularia buergeriana Miq. (Scrophulariaceae) (SB) has been used as an oriental medicine for the treatment of inflammatory diseases, such as neuritis and pharyngolaryngitis.

PURPOSE

We explored the therapeutic effects of S. buergeriana ethanol extract (SBE) on airway inflammation in ovalbumin (OVA)-induced asthmatic mice and lipopolysaccharide (LPS)-stimulated RAW264.7 cells.

METHODS

Mice were intraperitoneally injected with OVA on days 0 and 14 to elevate the immune response. On days 21 to 23, the mice were challenged with OVA solution and SBE (20 and 40 mg/kg) was administered daily by oral gavage from days 18 to 23. RAW264.7 cells were pretreated with SBE 1 h before LPS stimulation.

RESULTS

SBE administration effectively suppressed inflammatory cell infiltration, the expression of interleukin (IL)-5, IL-13, and IL-17, immunoglobulin E, and airway hyperresponsiveness in an OVA-induced allergic asthma model. A reduction in histological alterations, including airway inflammation and mucus hypersecretion, was observed. These effects of SBE were accompanied by a decrease in matrix metalloproteinase-9 (MMP-9) expression and nuclear factor kappa B (NF-κB) phosphorylation. These responses were observed in LPS-stimulated RAW264.7 cells. SBE treatment reduced the mRNA expression of tumor necrosis factor (TNF)-α, IL-6, and MMP-9, and NF-κB phosphorylation, in LPS-stimulated RAW264.7 cells.

CONCLUSION

Our results indicated that SBE effectively attenuated airway inflammation in an OVA-induced allergic asthma model. These properties of SBE were thought to be involved in the suppression of NF-κB phosphorylation, suggesting that the material has the potential to regulate the development of allergic asthma.

Synergistic nourishing 'Yin' effect of iridoid and phenylpropanoid glycosides from Radix Scrophulariae in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Scrophulariae (RS), is a renowned traditional Chinese medicine used as nourishing 'Yin'. The iridoid glycosides (IG) and phenylpropanoid glycosides (PG) are main chemical constituents in RS. However, there had been no pharmacological experiment studies of synergy between IG and PG. Due to the constituents interactions, exploring their synergy profile is of great important for explaining the essence of nourishing 'Yin' efficacy of RS.

AIM OF STUDY

The present study was undertaken to evaluate synergistic nourishing 'Yin' effect of IG and PG from RS in vivo and in vitro through their immunoregulation and antioxidant activities.

MATERIALS AND METHODS

In this study, IG and PG fractions in RS were isolated and identified by High Performance Liquid Chromatography coupled with tandem quadrupole time-of-flight Mass Spectrometry (HPLC-Q-TOF-MS). The synergistic nourishing 'Yin' effect of two fractions were investigated in vivo and in vitro with thyroxine-induced 'Yin' deficiency (YD) mice model and primary splenic lymphocyte, respectively. The exterior syndrome signs and serologic and cellular biomarkers changes were detected. Then, the synergistic coefficient (SC) of IG and PG on every pharmacodynamics index were calculated by Webb method.

RESULTS

Compared with model and mono-therapy group (IG or PG group), IG combined with PG group significantly ameliorated YD by exerting immunoregulation and antioxidant effects. Based on the SC, IG and PG possessed a synergistic effect on heart rate, average speed, upright times, spleen index, LPO, SOD, IL-6, Na⁺-K⁺-ATP enzyme in vivo, and cAMP/cGMP, IFN-γ/IL-10, and MDA in vitro with SC > 1.

CONCLUSIONS

The nourishing 'Yin' benefits were clearly produced when IG and PG were used in combination, which provided the scientific evidence of multiple-components and multiple-approach synergistic effect of Chinese traditional herbal medicine to control and management of diseases.

Protective effects of Astragalus kahiricus root extract on ethanol-induced retrograde memory impairments in mice

Introduction: Alzheimer’s disease (AD) is a neurodegenerative disorder that has no definite cure. Currently, there is great interest in using plant-based medicines to treat AD. In the present study, the neuroprotective effects of Astragalus kahiricus root extract were evaluated in a retrograde amnesia model. Methods: Male albino mice were given four training sessions in the Morris water maze for seven consecutive days. Treated groups were administered A. kahiricus (25 or 50 mg/kg, i.p.) before ethanol (3.5 gm/kg, i.p) injection. All animals were given a test session in the Morris water maze apparatus. Acetylcholinesterase activity and the levels of oxidative stress biomarkers were also measured. Results: Memory impairment was observed, after ethanol administration, as increased escape latency time and path length travelled by the animals. On the other hand, A. kahiricus significantly reduced both escape latency time and path length. In addition, the extract demonstrated an inhibitory effect on acetylcholinesterase activity and total nitrite level. Moreover, A. kahiricus significantly increased the level of reduced glutathione in mice brain. Conclusion: This study demonstrated the potential behavioural and biochemical neuroprotective properties of A. kahiricus root extract, which might further be considered an important candidate for the treatment of AD.

Guided isolation of new iridoid glucosides from Anarrhinum pubescens by high-performance thin-layer chromatography-acetylcholinesterase assay

Plants are an important source of natural iridoids. This study demonstrates for the first time the acetylcholinesterase (AChE) inhibitory activity of iridoids belonging to the class of antirrhinosides. As iridoids distinguish the chemical composition of most species of the Plantaginaceae family, the active AChE inhibitors were investigated in the hydro-alcoholic extract of Anarrhinum pubescens Fresen. High-performance thin-layer chromatography (HPTLC) in combination with the AChE inhibition assay is a time and material saving methodology, and thus was employed to directly point to the individual enzyme inhibitors occurring in the plant. The effect-directed screening successfully discovered three active metabolites. These were characterized as antirrhinoside-derived iridoids. Two of these are here reported as newly isolated natural compounds. Identification of the two new metabolites was based on analysis of their collected spectroscopic data (HRMS, 1D and 2D NMR). Their structures were elucidated to be 6-O-, 6'-O-di-trans-cinnamoyl-antirrhinoside (1) and 5-O-, 6-O-difoliamenthoyl-antirrhinoside (3), while the previously known compound 6-O-foliamenthoyl-(6'-O-cinnamoyl)-antirrhinoside (2) was assigned by extensive analysis of its HRMS and HRMS/MS data. The activity of the isolated compounds was referred to the known AChE inhibitor rivastigmine, i.e. their activity were calculated and expressed as values equivalently to rivastigmine. This neuroprotective potential of iridoids mediated through AChE inhibition promote them to compete as natural curatives for neurodegenerative disorders like Alzheimer's disease.

Devil's claw (Harpagophytum procumbens) and chronic inflammatory diseases: A concise overview on preclinical and clinical data

Devil's Claw is a traditional medicine that has been long used a wide range of health conditions, including indigestion, fever, allergic reactions, and rheumatism. The main compounds are iridoid glycosides, including harpagoside, harpagide, and procumbide. However, harpagoside is the most responsible for therapeutic activity, and its content is used as reference standard. Here, we analyzed and summarized preclinical and clinical studies focusing on therapeutic efficacy of devil's claw preparations in pathological conditions in which inflammation plays a key causative role.

Harpagoside Rescues the Memory Impairments in Chronic Cerebral Hypoperfusion Rats by Inhibiting PTEN Activity

Vascular dementia (VaD) is the second most common dementia worldwide. Unlike Alzheimer's disease, VaD does not yet have effective therapeutic drugs. Harpagoside is the most important component extracted from Harpagophytum procumbens, a traditional Chinese medicine that has been widely used. The neuroprotective effects of harpagoside have been studied in Aβ- and MPTP-induced neurotoxicity. However, whether harpagoside is protective against VaD is not clear. In this study, with the use of chronic cerebral hypoperfusion rats, a well-known VaD model, we demonstrated that chronic administration (two months) of harpagoside was able to restore both the spatial learning/memory and fear memory impairments. Importantly, the protective effects of harpagoside were not due to alterations in the physiological conditions, metabolic parameters, or locomotor abilities of the rats. Meanwhile, we found that harpagoside suppressed the overactivation of PTEN induced by CCH by enhancing PTEN phosphorylation. Furthermore, harpagoside elevated the activity of Akt and inhibited the activity of GSK-3β, downstream effectors of PTEN. Overall, our study suggested that harpagoside treatment might be a potential therapeutic drug targeting the cognitive impairments of VaD.

Ginsenosides Rg5 and Rk1 Enriched Cultured Wild Ginseng Root Extract Bioconversion of Pediococcus pentosaceus HLJG0702: Effect on Scopolamine-Induced Memory Dysfunction in Mice

Wild ginseng is known to contain additional physiologically and pharmacologically active substances than common ginseng. The utilization of this herb can be maximized by altering its composition via tissue culture generating adventitious roots. We enriched the content of specific ginsenosides and investigated their role in ameliorating memory impairment. Cultured wild ginseng root was subjected to extraction, steaming, and fermentation using Pediococcus pentosaceus HLJG0702 to enhance the levels of ginsenosides Rg5 /Rk1. The analysis of product, HLJG0701, confirmed target ginsenosides. We analyzed the inhibitory effect of ginsenoside Rg5/Rk1, HLJG0701 and the raw material on acetylcholinesterase. Further, we performed Morris water maze, Y-maze, and passive avoidance tasks with mice exhibiting memory deficit induced by scopolamine, and we analyzed the concentrations of acetylcholinesterase and acetylcholine in their brains. Studies showed that the levels of ginsenosides Rg5 /Rk1, not found in the raw material, were enhanced in HLJG0701. Ginsenosides and HLJG0701 significantly inhibited acetylcholinesterase unlike the raw material. In all behavioral tasks, HLJG0701 showed memory improvement. It reduced acetylcholinesterase, whereas, it preserved acetylcholine in brain. In conclusion, cultured wild ginseng root extract fermented by P. pentosaceus HLJG0702 contains the distinctive ginsenosides Rg5/Rk1, which may ameliorate memory impairment via inhibition of acetylcholinesterase resulting in increased acetylcholine levels in the brain.

Neuroprotective effects of novel nanosystems simultaneously loaded with vinpocetine and piracetam after intranasal administration

AIMS

The study aim was to test the efficacy of a novel created hybrid nanosystem compared to other nanosystems in treatment of scopolamine induced memory impairment.

MAIN METHODS

The fabrication and characterization of nanoformulations (microemulsion, liposomes, ethosomes, transfersomes and transethosomes) coencapsulating two cognitive enhancers; piracetam and vinpocetine delivered intranasally, in addition to a novel nanocomposite microemulsion/vesicular nanoformulation was described.

KEY FINDINGS

Formulations delivered the drugs across sheep nasal mucosa, with cumulative percentage reaching 29.99% for vinpocetine and 57.78% for piracetam. While the solution form of the drugs was totally ineffective, the selected transethosomal, microemulsion and nanocomposite formulations reversed the scopolamine induced effect on the step through latency of passive avoidance test and the spontaneous alternation behavior in Y maze test, further confirmed by histopathlogical examination. All three nanoformulations significantly decreased the acetylcholinesterase activity and the extent of lipid peroxidation by 32-42%. The nanocomposite formulation was superior to the microemulsion and transethosomal formulations in its anti-inflammatory and antiapoptotic effects, delineated by higher extent of inhibition of COX-2 and caspase 3 expression respectively.

SIGNIFICANCE

Results support the hypothesis that the novel microemulsion/vesicular nanocomposite system is a promising neuroprotective modality for intranasal brain targeting which is worthy of exploitation in other brain diseases.

Neuroprotective effects of Scrophularia buergeriana extract against glutamate-induced toxicity in SH-SY5Y cells

The aim of this study was to investigate the antioxidant and anti-apoptotic activities, as well as the underlying mechanisms of action, of Scrophularia buergeriana (S. buergeriana) extract (SBE) in glutamate-induced SH-SY5Y cell death. The roots of S. buergeriana were extracted with 70% ethanol, and standardized SBE was used in this study. To induce cytotoxicity, the SH-SY5Y cells were exposed to glutamate for 3 h, or pre-treated with SBE for 1 h, and subsequently incubated with glutamate for 3 h. The neuro-protective effects were assessed by measuring cell viability and the total glutathione contents using commercial kits. The antioxidant and anti-apoptotic mechanisms of action of SBE were evaluated by western blot analysis. The results confirmed that glutamate-induced toxicity was caused by reactive oxygen species (ROS) production, leading to oxidative stress and DNA damage, thus leading to cell death. However, treatment of the SH-SY5Y cells with SBE significantly increased the viability of the cells exposed to glutamate by upregulating the levels of antioxidant proteins, such as superoxide dismutase (SOD)1, SOD2 and glutathione peroxidase-1 (GPx-1), and directly enhancing the total glutathione contents. Furthermore, SBE attenuated DNA impairment and decreased B-cell lymphoma-2 (Bcl-2)-associated X protein (Bax), cleaved caspase-3 and cleaved poly(adenosine diphosphate (ADP)-ribose) polymerase (PARP) activation. In addition, SBE upregulated Bcl-2 expression via p38 mitogen-activated protein kinases (MAPKs). On the whole, the findings of this study demonstrated that SBE exerts neuroprotective effects against glutamate-induced cell toxicity through its antioxidant and anti-apoptotic activities.

Stability towards the gastrointestinal simulated digestion and bioactivity of PAYCS and its digestive product PAY with cognitive improving properties

Pro-AlaTyr-Cys-Ser (PAYCS) was susceptible to digestion and its memory improving activity was linked to the activation of Nrf2/ARE and BDNF/CREB signaling.

Comparative Evaluation of Prosopis cineraria (L.) Druce and Its ZnO Nanoparticles on Scopolamine Induced Amnesia

Over recent years, utilization of green synthesized nanomaterials has been widely growing on human body because of its special properties. With the increasing acceptance of nanoparticle approach for various clinical treatments, the biosafety and toxicological effects on the vital organs such as central nervous system, have received more concern. Main focus of this study was to evaluate acute exposure of n-butanol fraction of Prosopis cineraria (L.) Druce hydroethanolic extract (BuPC) and green synthesized zinc oxide nanoparticles of BuPC (ZnOPC) on spatial cognition behavior, and to assess underlying mechanism by estimation of enzymatic antioxidative status along with acetylcholinesterase (AChE) activity in mice brain. Strongest in vitro antioxidant and AChE inhibitory activity exhibiting fraction, BuPC, was examined for inhibition kinetic study by Lineweaver-Burk and Dixon plots. BuPC was further used for fabrication ZnOPC and characterized by UV-visible spectroscopy, Fourier Transform Infrared (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X ray (EDX), and Dynamic Light Scattering (DLS) analysis. Old male swiss albino mice were randomly divided into seven groups and treated for 21 days. Subsequently spatial memory was determined by two behavioral models [Elevated plus maze (EPM) and Hebbs William maze (HWM)] and supernatant of brain homogenate was analyzed for enzymatic antioxidant level and AChE inhibitory activity. Zinc content of blood plasma and brain was estimated. Results showed prolonged transfer latency (TL) and time taken to reach reward chamber (TRC) by scopolamine was not ameliorated by the ZnOPC group, whereas BuPC group showed significant reduction in scopolamine induced increase in TL and TRC compared to control and scopolamine treated groups. ZnOPC alleviated enzymatic antioxidant activity and AChE as compared to donepezil and BuPC treated groups. Study concludes that ZnOPC attenuated spatial learning and memory by increase in oxidative stress and decrease in AChE activity at both dose levels. Our results suggest that BuPC exhibited a strong neuroprotective effect on cognitive deficit mice and it may be employed as a strong substance for the treatment of dementia whereas the green synthesized ZnOPC was not proficient to reverse the memory impairment induced by scopolamine.

Flavonoids as acetylcholinesterase inhibitors: Current therapeutic standing and future prospects

BACKGROUND

Acetylcholinesterase (AChE), a serine hydrolase, is primarily responsible for the termination of signal transmission in the cholinergic system, owing to its outstanding hydrolyzing potential. Its substrate acetylcholine (ACh), is a neurotransmitter of the cholinergic system, with a predominant effect on motor neurons involved in memory formation. So, by decreasing the activity of this enzyme by employment of specific inhibitors, a number of motor neuron disorders such as myasthenia gravis, glaucoma, Lewy body dementia, and Alzheimer's disease, among others, can be treated. However, the current-available AChE inhibitors have several limitations in terms of efficacy, therapeutic range, and safety.

SCOPE AND APPROACH

Primarily due to the non-compliance of current therapies, new, effective and safe inhibitors are being searched for, especially those which act through multiple receptor sites, but do not elicit undesirable effects. In this regard, the evaluation of phytochemicals such as flavonoids, can be a rational approach. The therapeutic potential of flavonoids has already been recognized agaisnt several ailments. This review deals with various plant-derived flavonoids, their preclinical potential as AChE inhibitors, in established assays, possible mechanisms of action, and structural activity relationship (SAR).

RESULTS AND CONCLUSIONS

Subsequently, a number of plant-derived flavonoids with outstanding efficacy and potency as AChE inhibitors, the mechanistic, their safety profiles, and pharmacokinetic attributes have been discussed. Through derivatization of these reported flavonoids, some limitation in efficacy or pharmacokinetic parameters can be addressed. The selected flavonoids ought to be tested in clinical studies to discover new neuro-therapeutic candidates.

Neuroprotective Effect and Molecular Mechanism of [6]-Gingerol against Scopolamine-Induced Amnesia in C57BL/6 Mice

We have investigated the neuroprotective and memory enhancing effect of [6]-gingerol (GIN), a pungent ingredient of ginger, using an animal model of amnesia. To determine the neuroprotective effect of GIN on cognitive dysfunction, scopolamine (SCO, 1 mg/kg, i.p.) was injected into C57BL/6 mice, and a series of behavioral tests were conducted. SCO-induced behavior changes and memory impairments, such as decreased alteration (%) in Y-maze test, increased mean escape latency in water maze test, diminished step-through latency in passive avoidance test, and shortened freezing time in fear condition test, were significantly prevented and restored by the oral administration of GIN (10 or 25 mg/kg/day). To further verify the neuroprotective mechanism of GIN, we have focused on the brain-derived neurotrophic factor (BDNF). The administration of GIN elevated the protein expression of BDNF, which was mediated via the activation of protein kinase B/Akt- and cAMP-response element binding protein (CREB) signaling pathway. These results suggest that GIN may have preventive and/or therapeutic potentials in the management of memory deficit and cognitive impairment in mice with amnesia.

The genus Scrophularia: a source of iridoids and terpenoids with a diverse biological activity

CONTEXT

Scrophularia genus (Scrophulariaceae) includes about 350 species commonly known as figwort. Many species of this genus grow wild in nature and have not been cultivated yet. However, some species are in danger of extinction.

OBJECTIVE

This paper reviews the chemical compounds, biological activities and the ethnopharmacology of some Scrophularia species.

MATERIALS AND METHODS

All information was obtained through reported data on bibliographic database such as Scopus, United States National Agricultural Library, Biological Abstracts, EMBASE, PubMed, MedlinePlus, PubChem and Springer Link (1934-2017). The information in different Pharmacopoeias on this genus was also gathered from 1957 to 2007.

RESULTS

The structures of 204 compounds and their biological activity were presented in the manuscript: glycoside esters, iridoid glycosides and triterpenoids are the most common compounds in this genus. Among them, scropolioside like iridoids have shown potential for anti-inflammatory, hepatoprotective and wound healing activity. Among the less frequently isolated compounds, resin glycosides such as crypthophilic acids have shown potent antiprotozoal and antimicrobial activities.

CONCLUSION

The Scrophularia genus seems to be a rich source of iridoids and terpenoids, but isolation and identification of its alkaloids have been a neglected area of scientific study. The diverse chemical compounds and biological activities of this genus will motivate further investigation on Scrophularia genus as a source of new therapeutic medications.

Melandrii Herba Extract Attenuates H₂O₂-Induced Neurotoxicity in Human Neuroblastoma SH-SY5Y Cells and Scopolamine-Induced Memory Impairment in Mice

Oxidative stress plays a significant role in the etiology of a variety of neurodegenerative diseases. In this study, we found that Melandrii Herba extract (ME) attenuated oxidative-induced damage in cells. Mechanistically, ME exhibited protection from H₂O₂-induced neurotoxicity via caspase-3 inactivation, Bcl-2 downregulation, Bax upregulation, and MAPK activation (ERK 1/2, JNK 1/2, and p38 MAPK) in vitro. Moreover, our in vivo data showed that ME was able to attenuate scopolamine-induced cognitive impairment. These results provide in vitro and in vivo evidence that ME exhibits neuroprotective properties against oxidative stress, which suggests that ME is worthy of further investigation as a complementary, or even as an alternative, product for preventing and treating neurodegenerative disorders.

Can Co-Activation of Nrf2 and Neurotrophic Signaling Pathway Slow Alzheimer's Disease?

Alzheimer’s disease (AD) is a multifaceted disease that is hard to treat by single-modal treatment. AD starts with amyloid peptides, mitochondrial dysfunction, and oxidative stress and later is accompanied with chronic endoplasmic reticulum (ER) stress and autophagy dysfunction, resulting in more complicated pathogenesis. Currently, few treatments can modify the complicated pathogenic progress of AD. Compared to the treatment with exogenous antioxidants, the activation of global antioxidant defense system via Nrf2 looks more promising in attenuating oxidative stress in AD brains. Accompanying the activation of the Nrf2-mediated antioxidant defense system that reduce the AD-causative factor, oxidative stress, it is also necessary to activate the neurotrophic signaling pathway that replaces damaged organelles and molecules with new ones. Thus, the dual actions to activate both the Nrf2 antioxidant system and neurotrophic signaling pathway are expected to provide a better strategy to modify AD pathogenesis. Here, we review the current understanding of AD pathogenesis and neuronal defense systems and discuss a possible way to co-activate the Nrf2 antioxidant system and neurotrophic signaling pathway with the hope of helping to find a better strategy to slow AD.

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.

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

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

Iridoid Glycosides Fraction Isolated from Veronica ciliata Fisch. Protects against Acetaminophen-Induced Liver Injury in Mice

Veronica ciliata Fisch. has traditionally been used in Tibetan medicine for the treatment of hepatitis, cholecystitis, rheumatism, and urticaria. We analyzed the chemical composition of the iridoid glycosides fraction (IGF) isolated from V. ciliata and evaluated the antioxidant and hepatoprotective properties. The IGF was separated by high-speed countercurrent chromatography (HSCCC) and the main compounds were identified by ultra-performance liquid chromatography coupled to a photodiode array. We determined the in vitro antioxidant ability of the IGF through radical scavenging assays and assessed the in vivo hepatoprotective potential in an acetaminophen- (APAP-) induced acute liver injury murine model. The IGF was separated by HSCCC and three major iridoid glycosides (verproside, catalposide, and amphicoside) were identified as potent antioxidants and hepatoprotective compounds. Treatment with the IGF significantly suppressed the APAP-induced elevation in serum alanine aminotransferase, aspartate aminotransferase, and tumor necrosis factor-alpha (TNF-α); improved serum total antioxidant capacity; decreased malondialdehyde formation; elevated superoxide dismutase and glutathione activity; and decreased expression of proinflammatory factors (TNF-α, nuclear factor kappa B) in the liver. Finally, we examined the histopathology of resected livers for evidence of hepatoprotection. The protection conferred by the IGF may be related to the reinforcement of antioxidant defense systems.

Benzoate fraction from Gentiana rigescens Franch alleviates scopolamine-induced impaired memory in mice model in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

G. rigescens Franch (Long Dan Cao in Chinese) is a well-known TCM herb. It is clinically used with other drugs for the treatment of brain diseases such as epilepsy, postherpetic neuralgia in China.

AIM OF STUDY

In our previous study, the 11 dihydroxybenzoates compounds with NGF mimicking activity from G. rigescens Franch were found. In the present study, the neurogenesis and neuroprotection of a mixture of benzoates ( n-GS) were investigated in animal level.

MATERIALS AND METHODS

The NGF mimicking activity of n-GS from G. rigescens Franch was examined in PC12 cells. The neurogenesis effects of n-GS were investigated in ICR mice with 5-bromo-2-deoxyuridine (BrdU) and neuronal neclei (NeuN) double immunostaining. Furthermore, the neuroprotection effects of n-GS on the memory in a scopolamine (SCO)-induced mouse model were evaluated with animal behavior tests.

RESULTS

The NGF-mimicking function and neurogenesis of n-GS were observed in PC12 cells and in normal mice. Subsequently, we investigated the effects of n-GS on the memory in a SCO-induced mouse model. In Y-maze test, SCO significantly lowered the alternation. This finding was reversed by n-GS and donepezil (DONE). SCO significantly impaired the mice's performance in novel object recognition (NOR) and Morris water maze (MWM) tests. The time spent to explore the novel object was longer in the n-GS- and DONE-treated groups than in the SCO control group. In the MWM test, the escape latency of n-GS- and DONE-treated groups was shorter than that of the SCO control group. Mechanism study showed that SCO significantly reduced superoxide dismutase (SOD) but increased the activities of acetylcholinesterase (AChE) and the levels of malondialdehyde (MDA) in the hippocampus and cerebral cortex, which all can be improved by n-GS and DONE. Additionally, the phosphorylation of type 1 insulin-like growth factor (IGF-1) receptor, extracellular signal-regulated kinase (ERK), and cAMP responsive element-binding (CREB) protein in the hippocampus was significantly up-regulated in the treatment group compared with that in the SCO group.

CONCLUSIONS

n-GS could alleviate impaired memory of the SCO-induced mice model by inhibiting AChE activity and oxidative stress, and regulating the IGF-1R/ERK signaling pathway.