Valeriana amurensis improves Amyloid-beta 1-42 induced cognitive deficit by enhancing cerebral cholinergic function and protecting the brain neurons from apoptosis in mice

Mechanistic insights and emerging therapeutic stratagems for Alzheimer's disease

Alzheimer's disease (AD), a multi-factorial neurodegenerative disorder has affected over 30 million individuals globally and these numbers are expected to increase in the coming decades. Current therapeutic interventions are largely ineffective as they focus on a single target. Development of an effective drug therapy requires a deep understanding of the various factors influencing the onset and progression of the disease. Aging and genetic factors exert a major influence on the development of AD. Other factors like post-viral infections, iron overload, gut dysbiosis, and vascular dysfunction also exacerbate the onset and progression of AD. Further, post-translational modifications in tau, DRP1, CREB, and p65 proteins increase the disease severity through triggering mitochondrial dysfunction, synaptic loss, and differential interaction of amyloid beta with different receptors leading to impaired intracellular signalling. With advancements in neuroscience tools, new inter-relations that aggravate AD are being discovered including pre-existing diseases and exposure to other pathogens. Simultaneously, new therapeutic strategies involving modulation of gene expression through targeted delivery or modulation with light, harnessing the immune response to promote clearance of amyloid deposits, introduction of stem cells and extracellular vesicles to replace the destroyed neurons, exploring new therapeutic molecules from plant, marine and biological sources delivered in the free state or through nanoparticles and use of non-pharmacological interventions like music, transcranial stimulation and yoga. Polypharmacology approaches involving combination of therapeutic agents are also under active investigation for superior therapeutic outcomes. This review elaborates on various disease-causing factors, their underlying mechanisms, the inter-play between different disease-causing players, and emerging therapeutic options including those under clinical trials, for treatment of AD. The challenges involved in AD therapy and the way forward have also been discussed.

Total flavonoids of Cynomorium songaricum attenuates cognitive defects in an Aβ 1-42 -induced Alzheimer's disease rat model by activating BDNF/TrkB signaling transduction

Alzheimer's disease (AD) is a degenerative disorder characterized by cognitive dysfunction and BDNF/TrkB is a well-conceived anti-AD signaling. Cynomorium songaricum Rupr. ( C. songaricum ) is a herb with promising neuroprotective effects and the function is majorly attributed to flavonoids. The current study attempted to explore the effects of total flavonoids of C. songaricum (CS) on AD model by focusing on changes in BDNF/TrkB axis. AD model was induced in rats via transcranial injection of Aβ 1-42 and AD symptoms treated with CS of three doses. Donepezil was used as the positive control. Changes in rat memory and learning abilities, brain histological, apoptosis, production of neurotransmitters, BDNF/TrkB axis, and apoptosis-related markers were measured. The injection of Aβ 1-42 induced cognitive dysfunction in AD rats. The integrity of brain tissue structure was destructed and apoptosis was induced in AD rats, in which was found the increased production of AChE and Aβ 1-42 , and decreased production of ChAT, ACH. At the molecular level, the expression of BDNF, TrkB, and Bcl-2 was suppressed, while the expression of Bax, caspase-3, and caspase-9 was induced. After the administration of CS, the memory and learning abilities of rats were improved, the production of neurotransmitter was restored, ordered arrangement of pyramidal cells was retained, and neuron apoptosis was inhibited. The attenuation of Aβ 1-42 -indcued impairments was associated with the activation of BDNF/TrkB axis and blockade of apoptosis-related pathways. Collectively, CS can improve learning and memory abilities in Aβ 1-42 -induced AD model rats. which may depend on the activation of the hippocampal BDNF/TrkB signaling pathway.

Neuroprotective Iridoids and Lignans from Valeriana amurensis

Valeriana amurensis (V. amurensis) is widely distributed in Northeast China. In addition to medicines, it has also been used to prepare food, wine, tobacco, cosmetics, perfume, and functional foods. Other studies have investigated the neuroprotective effects of V. amurensis extract. As the therapeutic basis, the active constituents should be further evaluated. In this paper, six new compounds (1-6) were isolated, including five iridoids (Xiecaoiridoidside A-E) and one bisepoxylignan (Xiecaolignanside A), as well as six known compounds (7-12). The neuroprotective effects of 1-12 were also investigated with amyloid β protein 1-42 (Aβ1-42)-induced injury to rat pheochromocytoma (PC12) cells. As a result, iridoids 1 and 2 and lignans 6, 8, and 9 could markedly maintain the cells' viability by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) and lactate dehydrogenase (LDH) release assay.

Naringin enhances long-term potentiation and recovers learning and memory deficits of amyloid-beta induced Alzheimer's disease-like behavioral rat model

Alzheimer's disease (AD), as the most typical type of dementia, is a chronic neurodegenerative disorder characterized by progressive learning and memory impairment. It is known that the main causes of AD are the accumulation of β-amyloid (Aβ) plaques and neurofibrillary tangles (NFT) containing hyperphosphorylated tau protein. Naringin is a flavonoid from citrus fruits, especially in grapefruit, which has anti-inflammatory, antioxidant, anti-apoptotic, and neuroprotective activities. However, the effect of naringin in AD caused by Aβ has not been clearly studied, and there are few studies on the electrophysiological aspect. Thus, we investigated the ex vivo neuroprotective effect of naringin through the long-term potentiation (LTP) on organotypic hippocampal slice cultures. We evaluated the in vivo effects of naringin (100 mg/kg/day) orally treated for 20 days on learning, memory, and cognition which was impaired by bilateral CA1 subregion injection of Aβ. Cognitive behaviors were measured 2 weeks after Aβ injection using behavioral tests and the hippocampal expression of apoptotic and neurotrophic regulators were measured by immunoblotting. In hippocampal tissue slices, naringin dose-dependently increased the field excitatory postsynaptic potential (fEPSP) after theta burst stimulation and attenuated Aβ-induced blockade of fEPSP in the hippocampal CA1 area. In Aβ injected rats, naringin improved object recognition memory in the novel object test, avoidance memory in the passive avoidance test and spatial recognition memory in the Morris water maze test. In the hippocampus, naringin attenuated the Aβ-induced cyclooxygenase-2, Bax activation and Bcl-2, CREB, BDNF and TrkB inhibition. These results suggest that naringin has therapeutic potential to reduce neuronal inflammation and apoptosis induced by Aβ related with the BDNF/TrkB/CREB signaling.

Biological Evaluation of Valeriana Extracts from Argentina with Potent Cholinesterase Inhibition for the Treatment of Neurodegenerative Disorders and Their Comorbidities-The Case of Valeriana carnosa Sm. (Caprifoliaceae) Studied in Mice

Alzheimer's disease (AD) is a neurodegenerative disorder whose pathophysiology includes the abnormal accumulation of proteins (e.g., β-amyloid), oxidative stress, and alterations in neurotransmitter levels, mainly acetylcholine. Here we present a comparative study of the effect of extracts obtained from endemic Argentinian species of valerians, namely V. carnosa Sm., V. clarionifolia Phil. and V. macrorhiza Poepp. ex DC from Patagonia and V. ferax (Griseb.) Höck and V. effusa Griseb., on different AD-related biological targets. Of these anxiolytic, sedative and sleep-inducing valerians, V. carnosa proved the most promising and was assayed in vivo. All valerians inhibited acetylcholinesterase (IC₅₀ between 1.08-12.69 mg/mL) and butyrylcholinesterase (IC₅₀ between 0.0019-1.46 mg/mL). They also inhibited the aggregation of β-amyloid peptide, were able to chelate Fe²⁺ ions, and exhibited a direct relationship between antioxidant capacity and phenolic content. Moreover, V. carnosa was able to inhibit human monoamine oxidase A (IC₅₀: 0.286 mg/mL (0.213-0.384)). A daily intake of aqueous V. carnosa extract by male Swiss mice (50 and 150 mg/kg/day) resulted in anxiolytic and antidepressant-like behavior and improved spatial memory. In addition, decreased AChE activity and oxidative stress markers were observed in treated mouse brains. Our studies contribute to the development of indigenous herbal medicines as therapeutic agents for AD.

An Effective Chromatography Process for Simultaneous Purification and Separation of Total Lignans and Flavonoids from Valeriana amurensis

An effective chromatography process was developed and validated for simultaneous purification and separation of total lignans and flavonoids from Valeriana amurensis. The total lignans and flavonoids in Valeriana amurensis extract were prepurified with macroporous resin column chromatography, and the conditions were optimized as follows: 40 mg/mL Valeriana amurensis extract (2.0 g) solution was loaded onto an AB-8 resin column with a diameter-to-height ratio of 1:7, followed by adsorption for 6 h; then, the column was eluted successively with 5 BV water and 10% and 50% ethanol at a flow rate 2 BV/h. The obtained 50% ethanol fraction was further repurified and separated by polyamide resin column chromatography to obtain the total lignans and flavonoids, respectively. The chromatography conditions were optimized as follows: a 50% ethanol fraction (1.0 g) was mixed with 1.0 g polyamide resin and loaded onto a polyamide resin (60-100 mesh) column with a diameter-to-height ratio of 1:3; then, the column was eluted successively with 6 BV water and 40% and 80% ethanol at a flow rate of 4 BV/h. The total lignans and flavonoids were obtained from water and 80% ethanol fraction, respectively. The content and recovery of standard compounds in total lignans and flavonoids were analyzed with HPLC-PDA, and the feasibility of the process was confirmed.

The potential of Valeriana as a traditional Chinese medicine: traditional clinical applications, bioactivities, and phytochemistry

Valeriana plants are members of the Caprifoliaceae family, which include more than 200 species worldwide. We summarized previous reports on traditional clinical applications, bioactivities, and phytochemistry of Valeriana by searching electronic databases of Science Direct, Web of Science, PubMed, and some books. Some Valeriana species have been used as traditional medicines, demonstrating calming fright and tranquilizing mind, promoting Qi and blood, activating blood circulation and regulating menstruation, dispelling wind and eliminating dampness, regulating Qi-flowing to relieve pain, and promoting digestion and checking diarrhea, and treating diseases of the nervous, cardiovascular, and digestive systems, inflammation, gynecology, and others. Pharmacology studies revealed the effects of Valeriana, including sedative, hypnotic, antispasmodic, analgesic, antidepressant, anxiolytic, anticonvulsant, antiepileptic, neuroprotective, antibacterial, antiviral, cytotoxic, and antitumor effects as well as cardiovascular and cerebrovascular system improvements. More than 800 compounds have been isolated or identified from Valeriana, including iridoids, lignans, flavonoids, sesquiterpenoids, alkaloids, and essential oils. Constituents with neuroprotective, anti-inflammatory, cytotoxic, and sedative activities were also identified. However, at present, the developed drugs from Valeriana are far from sufficient. We further discussed the pharmacological effects, effective constituents, and mechanisms directly related to the traditional clinical applications of Valeriana, revealing that only several species and their essential oils were well developed to treat insomnia. To effectively promote the utilization of resources, more Valeriana species as well as their different medicinal parts should be the focus of future related studies. Clinical studies should be performed based on the traditional efficacies of Valeriana to facilitate their use in treating diseases of nervous, cardiovascular, and digestive systems, inflammation, and gynecology. Future studies should also focus on developing effective fractions or active compounds of Valeriana into new drugs to treat diseases associated with neurodegeneration, cardiovascular, and cerebrovascular, inflammation and tumors. Our review will promote the development and utilization of potential drugs in Valeriana and avoid wasting their medicinal resources.

Phytotherapeutic Approaches to the Prevention of Age-Related Changes and the Extension of Active Longevity

Maintaining quality of life with an increase in life expectancy is considered one of the global problems of our time. This review explores the possibility of using natural plant compounds with antioxidant, anti-inflammatory, anti-glycation, and anti-neurodegenerative properties to slow down the onset of age-related changes. Age-related changes such as a decrease in mental abilities, the development of inflammatory processes, and increased risk of developing type 2 diabetes have a significant impact on maintaining quality of life. Herbal preparations can play an essential role in preventing and treating neurodegenerative diseases that accompany age-related changes, including Alzheimer’s and Parkinson’s diseases. Medicinal plants have known sedative, muscle relaxant, neuroprotective, nootropic, and antiparkinsonian properties. The secondary metabolites, mainly polyphenolic compounds, are valuable substances for the development of new anti-inflammatory and hypoglycemic agents. Understanding how mixtures of plants and their biologically active substances work together to achieve a specific biological effect can help develop targeted drugs to prevent diseases associated with aging and age-related changes. Understanding the mechanisms of the biological activity of plant complexes and mixtures determines the prospects for using metabolomic and biochemical methods to prolong active longevity.

Neuroprotective role of Diosgenin, a NGF stimulator, against Aβ (1-42) induced neurotoxicity in animal model of Alzheimer's disease

Diosgenin is a neurosteroid derived from the plants and has been previously reported for its numerous health beneficial properties, such as anti-arrhythmic, hypolipidemic, and antiproliferative effects. Although several studies conducted earlier suggested cognition enhancement actions of diosgenin against neurodegenerative disorders, but the molecular mechanisms underlying are not clearly understood. In the present study, we investigated the neuroprotective effect of diosgenin in the Wistar rats that received an intracerebroventricular injection of Amyloid-β (1-42) peptides, representing a rodent model of Alzheimer's disease (AD). Animals were treated with 100 and 200 mg/kg/p.o of diosgenin for 28 days, followed by Amyloid-β (1-42) peptides infusion. Animals were assessed for the spatial learning and memory by using radial arm maze and passive avoidance task. Subsequently, animals were euthanized and brains were collected for biochemical estimations and histopathological studies. Our results revealed that, diosgenin administration dose dependently improved the spatial learning and memory and protected the animals from Amyloid-β (1-42) peptides induced disrupted cognitive functions. Further, biochemical analysis showed that diosgenin successfully attenuated Amyloid-β (1-42) mediated plaque load, oxidative stress, neuroinflammation and elevated acetylcholinesterase activity. In addition, histopathological evaluation also supported neuroprotective effects of diosgenin in hippocampus of rat brain when assessed using hematoxylin-eosin and Cresyl Violet staining. Thus, the aforementioned effects suggested protective action of diosgenin against Aβ (1-42) induced neuronal damage and thereby can serve as a potential therapeutic candidate for AD.

The sesquiterpenoid valerenic acid protects neuronal cells from the detrimental effects of the fungicide benomyl on apoptosis and DNA oxidation

BACKGROUND

Valerenic acid (VA), a sesquiterpenoid of the plant Valeriana officinalis, has attracted attention of the research community due to its potential positive role against neurodegenerative diseases induced by chemicals. However, the relevant evidence in the literature is scarce. Therefore, this study aimed to examine the putative protective role of VA on the toxic effects of the fungicide benomyl on SH-SY5Y neural cells.

METHODS

Cell viability was determined via the MTT and NRU assays, DNA damage was assessed via comet assay and apoptosis was evaluated through the expression of relevant genes.

RESULTS

According to the results, exposure of the cells to benomyl enhanced viability inhibition and promoted DNA damage and apoptosis since the expression levels of the genes coding for MAPK8, NF-kB, Bax, Caspase-9 and Caspase-3 were increased. Treatment of the cells with VA ameliorated these effects in a concentration dependent manner.

CONCLUSION

It is concluded that the molecular mechanism through which benomyl exerts its toxic action appears to depend on DNA oxidation and apoptosis induction. Furthermore, VA, a plant-derived compound is a protective antioxidant against pesticide-induced toxicity. Therefore, herbs, extracts and compounds of plant origin could be used as nutritional supplements that back up the beneficial role of medicine in neurodegenerative diseases.

Poria cocos could ameliorate cognitive dysfunction in APP/PS1 mice by restoring imbalance of Aβ production and clearance and gut microbiota dysbiosis

Alzheimer's disease (AD) is the most common neurodegenerative disorder. Amyloid beta-protein (Aβ) plaques, which are the hallmark of AD, are formed from the imbalance of Aβ production and clearance accompanied by neuroinflammation, gut dysbiosis, and metabolite dysfunction. All of these processes give rise to neurochemical deficiencies and synaptic dysfunction, which ultimately contribute to recognition dysfunction. Poria cocos (PC), which contains multiple active ingredients, plays a significant role in the treatment of multiple-pathogenesis senile diseases such as AD. Nevertheless, there are only very few investigations on the intricate action mechanism of PC for the treatment of AD. In this study, we evaluate the multi-target cure effect of PC on APP/PS1 mice by behavioral, immunohistochemical (IHC), targeted metabolomics, and 16S rRNA sequencing experiments. Mice treated with PC showed significant improvements in cognitive function as evaluated by the behavioral experiment. IHC revealed that PC treatment relieved Aβ deposition by reducing the formation of Aβ and increasing its clearance. Moreover, PC treatment improved gut dysbiosis, which reversed the metabolite dysfunction of bile acid. These findings reveal that PC is a promising therapeutic agent, which might ameliorate the cognitive function of AD by restoring the imbalance of Aβ production and clearance and gut microbiota dysbiosis.

Plant Species of Sub-Family Valerianaceae-A Review on Its Effect on the Central Nervous System

Valerianaceae, the sub-family of Caprifoliaceae, contains more than 300 species of annual and perennial herbs, worldwide distributed. Several species are used for their biological properties while some are used as food. Species from the genus Valeriana have been used for their antispasmodic, relaxing, and sedative properties, which have been mainly attributed to the presence of valepotriates, borneol derivatives, and isovalerenic acid. Among this genus, the most common and employed species is Valerianaofficinalis. Although valerian has been traditionally used as a mild sedative, research results are still controversial regarding the role of the different active compounds, the herbal preparations, and the dosage used. The present review is designed to summarize and critically describe the current knowledge on the different plant species belonging to Valerianaceae, their phytochemicals, their uses in the treatment of different diseases with particular emphasis on the effects on the central nervous system. The available information on this sub-family was collected from scientific databases up until year 2020. The following electronic databases were used: PubMed, Scopus, Sci Finder, Web of Science, Science Direct, NCBI, and Google Scholar. The search terms used for this review included Valerianaceae, Valeriana, Centranthus, Fedia, Patrinia, Nardostachys, Plectritis, and Valerianella, phytochemical composition, in vivo studies, Central Nervous System, neuroprotective, antidepressant, antinociceptive, anxiolytic, anxiety, preclinical and clinical studies.

Plasma and intracerebral pharmacokinetics and pharmacodynamics modeling for the acetylcholine releasing effect of ginsenoside Rg1 in mPFC of Aβ model rats

Ginsenoside Rg1 is a major bioactive component of ginseng. Limited information is available regarding Rg1 concentrations in the central neural system and the corresponding relationship of plasma/intracerebral concentrations, and intracerebral effects of Rg1. Awake Aβ model rats received a single subcutaneous administration of Rg1. Concentrations of unbound Rg1 and acetylcholine in the brain extracellular fluid and Rg1 in plasma were then determined. An E_max-two compartment pharmacokinetic/pharmacodynamics (PK/PD) model without effect compartment was finally obtained by evaluating three mechanism-based models. The corresponding relationship between the plasma PK and PD of Rg1 can be described as E = 119.05•C/(73.42 + C).[Formula: see text].

Ameliorating effect of Citrus aurantium extracts and nobiletin on β‑amyloid (1‑42)‑induced memory impairment in mice

The aim of the present study was to evaluate the neuroprotective effect of Citrus aurantium extract (CAE) and nobiletin against amyloid β 1‑42 (Aβ 1‑42)‑induced spatial learning and memory impairment in mice. After injecting Aβ 1‑42 (5 µl/2.5 min, intracerebroventricular injection), amnesic mice were orally administered CAE and nobiletin for 28 days. Memory, spatial and cognitive ability were measured using passive avoidance and a Morris water maze task. Acetylcholinesterase (AchE) activity was investigated in the hippocampus and cortex using commercial kits and the analysis of Bax, Bcl‑2, and cleaved caspase‑3 protein expression by western blot assays was used to confirm the anti‑apoptotic mechanism of CAE and nobiletin. The present study confirmed impairments in learning and memory in the Aβ‑induced neurodegenerative mice with increased AchE activity in the brain. However, the daily administration of CAE and nobiletin reduced the spatial learning deficits and increased the AchE activity in the cortex and hippocampus. Furthermore, CAE and nobiletin significantly downregulated the Bax and cleaved caspase‑3 protein expression and upregulated the Bcl‑2 and Bcl‑2/Bax expression in the cortex and hippocampus of Aβ‑treated mice. These results suggest that CAE and nobiletin exert a neuroprotective effect by regulating anti‑apoptotic mechanisms, including reduced AchE activity in the cortex and hippocampus of the cognitive deficit mouse model.

Sesquiterpenoids from the roots and rhizomes of Valeriana amurensis and their effects on NGF-induced neurite outgrowth in PC12 cells

Two new sesquiterpenoids, including a kessane-type sesquiterpenoid (1) and one bisabolane derivative (2), together with fourteen known sesquiterpenoids (3-16), were isolated from the roots and rhizomes of Valeriana amurensis. The structures of new compounds were established on the basis of extensive spectroscopic analysis. All isolates were evaluated for their effects on nerve growth factor (NGF)-mediated neurite outgrowth in pheochromocytoma (PC12) cells. As a results, four compounds including 10-12 and 15 showed potent promoting effects at the concentration of 10 µM on NGF-induced neurite outgrowth in PC12 cells with the differentiation rate of 11.84%, 12.21%, 13.77% and 12.16%, respectively.

Valeriana jatamansi: An herbaceous plant with multiple medicinal uses

Valeriana jatamansi Jones (Family: Caprifoliaceae), a high value medicinal plant, was distributed in many countries of Asia. The species possesses important valepotriates and is a good source of flavones or flavone glycosides, lignans, sesquiterpenoids or sesquiterpenoid glycoside, bakkenolide type sesquiterpenoids, phenolic compounds, terpinoids, etc. The use of the species in traditional and modern medicines is well known. For instance, V. jatamansi is very important for its insect repelling and antihelmethic properties. Similarly, sedative, neurotoxic, cytotoxic, antidepressant, antioxidant, and antimicrobial activities of the species in various ailments in the indigenous system of medicine, particularly in Asia, are reported. This review focuses on the detailed phytochemical composition, medicinal uses, and pharmacological properties of V. jatamansi along with analysis of botanical errors in published literature and reproducibility of the biomedical researches on this multipurpose herbaceous species.

Medicinal plants with acetylcholinesterase inhibitory activity

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

Anti-amyloidogenic properties of an ethyl acetate fraction from Actinidia arguta in Aβ1-42-induced ICR mice

This study aimed to investigate the ameliorating effect of an ethyl acetate fraction from the fruit Actinidia arguta (EFAA) on amyloid beta (Aβ)-induced neurotoxicity and cognitive deficits in ICR mice. EFAA showed potent protective effects against Aβ-induced neurotoxicity through 2',7'-dichlorofluorescein diacetate (DCF-DA), 2',3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) release into the assay medium. EFAA treatment reduced the intracellular ROS level and lactate dehydrogenase (LDH) release in the mitochondria, and increased cell viability in Aβ-induced neuroblastoma MC-IXC cells. The administration of EFAA significantly attenuated Aβ-induced learning and memory deficits, which were evaluated by Y-maze, passive avoidance, and Morris water maze tests. Furthermore, EFAA showed the ameliorating effect of cholinergic functions by increasing acetylcholine (ACh) levels and decreasing acetylcholinesterase (AChE) activity, and protected antioxidant systems by increasing superoxide dismutase (SOD) and decreasing the oxidized glutathione (GSH)/total GSH and malondialdehyde (MDA) in the brain. Finally, EFAA prevented mitochondrial dysfunction via regulating apoptotic signaling molecules including phosphorylated Akt (p-Akt), phosphorylated tau (p-tau), Bax, and cytochrome c in the brain tissues. Therefore, the present study suggests that EFAA might be a potential source of natural antioxidants with the ability to ameliorate Aβ-induced amnesia.

Therapy of Dredging the Bowels Enhanced the Neuroprotective Effect of Nourishing Kidney Herbs on Hippocampal Cholinergic System in Alzheimer's Disease Model Rat Induced by Aβ 1-42

BACKGROUND

Therapy of nourishing kidney has been used for treating memory deficits of Alzheimer's disease (AD) for thousands of years based on traditional Chinese medicine. However, we found the therapy of dredging the bowels could alleviate both memory deficits and mental symptoms of AD in clinic.

OBJECTIVE

To determine whether the therapy of dredging the bowels could enhance the neuroprotective effect of nourishing kidney herbs for treating AD rats, and to explore the underlying mechanism of the combination of nourishing kidney and dredging the bowels (NKDB) herbs.

METHODS

60 rats were randomly divided into sham-operated group (SOG), model group (MG), nourishing kidney group (NKG), dredging the bowels group (DBG), nourishing kidney and dredging the bowels group (NKDBG), and donepezil hydrochloride group (DHG). The model establishment was performed by injecting Aβ 1-42 into the hippocampal CA1 region. Animals received aqueous solution of Chinese herbal medicine or western medicine while SOG received only distilled water. Ability of learning and memory were assessed by Morris water maze. Acetylcholinesterase(AChE) and choline acetyltransferase (ChAT) activity and positive cells in the hippocampus were detected by the biochemical and immunofluorescent assay.

RESULTS

All rats were in the same baseline. While after model establishment, ability of learning and memory of MG, NKG, DBG, NKDBG, and DHG were significantly impaired compared with SOG. Whereas after treatment, ability of learning and memory of NKG, DBG, NKDBG, and DHG were significantly improved compared with MG. Additionally, AChE activity of NKG, DBG, and NKDBG was significantly decreased, meanwhile ChAT activity showed an increased tendency. The number of AChE-positive cells and ChAT-positive cells of both NKDBG and DHG were significantly decreased and increased respectively, superior to those when compared with NKG and DBG. What's more, there was no significant difference between NKDBG and DHG.

CONCLUSION

Therapy of dredging the bowels could enhance the neuroprotective effect of nourishing kidney herbs by reversing morphological damage of hippocampal cholinergic system. Furthermore, treatment with NKDB herbs could be effectively against AD, providing a practical therapeutic strategy in clinic.

Pharmacognostical Sources of Popular Medicine To Treat Alzheimer's Disease

BACKGROUND

A large number of classical and recently discovered plants are indicated in preventing and/or treating Alzheimer's disease (AD).

OBJECTIVE

Name of plants with their anti-AD effects are important for their further use and investigation.

METHOD

A short overview of AD is given; anti-Alzheimer plants are given in a Table.

RESULTS

Various medicinal plants are listed here as sources of popular medicines to be used in cases when patients are afraid of developing and/or suffer from AD. Some of these plants have been used for centuries. The major sources in the literature, over one hundred of references are given for plants that show beneficial effect on the progress of AD.

CONCLUSION

Plant extracts are widely used addition to the synthetic drugs approved by various administrative authorities to stop/slow down the progress of symptoms of AD.

The p38 mitogen activated protein kinase regulates β-amyloid protein internalization through the α7 nicotinic acetylcholine receptor in mouse brain

Alzheimer's disease (AD) is one of the most devastating neurodegenerative disorders. Intracellular β-amyloid protein (Aβ) is an early event in AD. It induces the formation of amyloid plaques and neuron damage. The α7 nicotinic acetylcholine receptor (α7nAChR) has been suggested to play an important role in Aβ caused cognition. It has high affinity with Aβ and could mediate Aβ internalization in vitro. However, whether in mouse brain the p38 MAPK signaling pathway is involved in the regulation of the α7nAChR mediated Aβ internalization and their role in mitochondria remains little known. Therefore, in this study, we revealed that Aβ is internalized by cholinergic and GABAergic neurons. The internalized Aβ were found deposits in lysosomes/endosomes and mitochondria. Aβ could form Aβ-α7nAChR complex with α7nAChR, activates the p38 mitogen activated protein kinase (MAPK). And the increasing of α7nAChR could in return mediate Aβ internalization in the cortex and hippocampus. In addition, by using the α7nAChR agonist PNU282987, the p38 phosphorylation level decreases, rescues the biochemical changes which are tightly associated with Aβ-induced apoptosis, such as Bcl2/Bax level, cytochrome c (Cyt c) release. Collectively, the p38 MAPK signaling pathway could regulate the α7nAChR-mediated internalization of Aβ. The activation of α7nAChR or the inhibition of p38 MAPK signaling pathway may be a beneficial therapy to AD.

PROTECTIVE EFFECT OF IRIS GERMANICA L. IN Β-AMYLOID-INDUCED ANIMAL MODEL OF ALZHEIMER'S DISEASE

BACKGROUND

Alzheimer's disease (AD) is the most common cause of dementia that is an irretrievable chronic neurodegenerative disease. In the current study, we have examined the therapeutic effects of Iris germanica extract on Amyloid β (Aβ) induced memory impairment.

MATERIALS AND METHODS

Wistar rats were divided into five groups of 8 per each. Groups were as followed: control group which were normal rats without induction of AD, Aβ group which received Aβ (50 ng/side), iris 100 group which received Aβ + Iris (100 mg/kg), iris 200 group which received Aβ + Iris (200 mg/kg), and iris 400 group which received Aβ + Iris (400 mg/kg). AD was established by intrahippocampal injection of 50 ng/μl/side Aβ1-42. The day after surgery, animals in treatment groups received different doses of the aqueous extract of Iris by gavage for 30 days. Morris water maze test (MWM) was performed to assess the effects of I. germanica on learning and memory of rats with Aβ induced AD.

RESULTS

Data from MWM tests, including escape latency and traveled distance, demonstrated that I. germanica extract could markedly improve spatial memory in comparison to control. Moreover, the plant had a significantly better effect on the performance of AD rats in the probe test.

CONCLUSION

I. germanica extract can successfully reverse spatial learning dysfunction in an experimental model of AD. Further neuro psyco-pharmacological studies are mandatory to reveal the mechanism of action of this natural remedy in the management of AD symptoms.

Natural products against Alzheimer's disease: Pharmaco-therapeutics and biotechnological interventions

Alzheimer's disease (AD) is a severe, chronic and progressive neurodegenerative disease associated with memory and cognition impairment ultimately leading to death. It is the commonest reason of dementia in elderly populations mostly affecting beyond the age of 65. The pathogenesis is indicated by accumulation of the amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFT) in brain tissues and hyperphosphorylation of tau protein in neurons. The main cause is considered to be the formation of reactive oxygen species (ROS) due to oxidative stress. The current treatment provides only symptomatic relief by offering temporary palliative therapy which declines the rate of cognitive impairment associated with AD. Inhibition of the enzyme acetylcholinesterase (AChE) is considered as one of the major therapeutic strategies offering only symptomatic relief and moderate disease-modifying effect. Other non-cholinergic therapeutic approaches include antioxidant and vitamin therapy, stem cell therapy, hormonal therapy, use of antihypertensive or lipid-lowering medications and selective phosphodiesterase (PDE) inhibitors, inhibition of β-secretase and γ-secretase and Aβ aggregation, inhibition of tau hyperphosphorylation and intracellular NFT, use of nonsteroidal anti-inflammatory drugs (NSAIDs), transition metal chelators, insulin resistance drugs, etanercept, brain-derived neurotrophic factor (BDNF) etc. Medicinal plants have been reported for possible anti-AD activity in a number of preclinical and clinical trials. Ethnobotany, being popular in China and in the Far East and possibly less emphasized in Europe, plays a substantial role in the discovery of anti-AD agents from botanicals. Chinese Material Medica (CMM) involving Chinese medicinal plants has been used traditionally in China in the treatment of AD. Ayurveda has already provided numerous lead compounds in drug discovery and many of these are also undergoing clinical investigations. A number of medicinal plants either in their crude forms or as isolated compounds have exhibited to reduce the pathological features associated with AD. In this present review, an attempt has been made to elucidate the molecular mode of action of various plant extracts, phytochemicals and traditional herbal formulations investigated against AD as reported in various preclinical and clinical tests. Herbal synergism often found in polyherbal formulations were found effective to combat disease heterogeneity as found in complex pathogenesis of AD. Finally a note has been added to describe biotechnological improvement, genetic and genomic resources and mathematical and statistical techniques for empirical model building associated with anti-AD plant secondary metabolites and their source botanicals.

Chemical Components and Cardiovascular Activities of Valeriana spp

Valeriana spp. is a flowering plant that is well known for its essential oils, iridoid compounds such as monoterpenes and sesquiterpenes, flavonoids, alkaloids, amino acids, and lignanoids. Valeriana spp. exhibits a wide range of biological activities such as lowering blood pressure and heart rate, antimyocardial ischemia reperfusion injury, antiarrhythmia, and regulation of blood lipid levels. This review focuses on the chemical constituents and cardiovascular activities of Valeriana spp.

Protective effects of components of the Chinese herb grassleaf sweetflag rhizome on PC12 cells incubated with amyloid-beta42

The major ingredients of grassleaf sweetflag rhizome are β-asarone and eugenol, which can cross the blood-brain barrier and protect neurons. This study aimed to observe the neuroprotective effects and mechanisms of β-asarone and eugenol, components of the Chinese herb grassleaf sweetflag rhizome, on PC12 cells. First, PC12 cells were cultured with different concentrations (between 1 × 10^-10 M and 1 × 10^-5 M) of β-asarone and eugenol. Survival rates of PC12 cells were not significantly affected. Second, PC12 cells incubated with amyloid-beta42, which reduced cell survival, were cultured under the same conditions (1 × 10^-6 M β-asarone and eugenol). The survival rates of PC12 cells significantly increased, while expression levels of the mRNAs for the pro-apoptotic protein Bax decreased, and those for the anti-apoptotic protein Bcl mRNA increased. In addition, the combination of β-asarone with eugenol achieved better results than either component alone. Our experimental findings indicate that both β-asarone and eugenol protect PC12 cells through inhibiting apoptosis, and that the combination of the two is better than either alone.

Protective effects of low molecular weight chondroitin sulfate on amyloid beta (Aβ)-induced damage in vitro and in vivo

In the present study, we investigated the effects of low molecular weight chondroitin sulfate (LMWCS) on amyloid beta (Aβ)-induced neurotoxicity in vitro and in vivo. The in vitro results showed that LMWCS blocked Aβ25-35-induced cell viability loss and apoptosis, decreased intracellular calcium concentration, reactive oxygen species (ROS) levels, the mitochondrial membrane potential (MMP) depolarization, and the protein expression of Caspase-3. During in vivo experiments, LMWCS improved the cognitive impairment induced by Aβ1-40, increased the level of choline acetyltransferase (ChAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and decreased the level of malondialdehyde (MDA) and acetylcholinesterase (AChE) in the mouse brain. Moreover, LMWCS decreased the density of pyramidal cells of CA1 regions, and suppressed the protein expression of Bax/Bcl-2 and Caspase-3, -9 in the hippocampus of mice. In conclusion, LMWCS possessed neuroprotective properties against toxic effects induced by Aβ peptides both in vitro and in vivo, which might be related to anti-apoptotic activity. LMWCS might be a useful preventive and therapeutic compound for Alzheimer's disease.

B7 homolog 3 aggravates brain injury in a murine model of Streptococcus pneumoniae-induced meningitis

Despite the application of antibiotics, Streptococcus pneumoniae (SP)-induced meningitis continues to be a life-threatening disease with a high fatality rate and an elevated risk of serious neurological sequelae, particularly in developing countries. In this study, the contribution of the co-stimulatory molecule B7 homolog 3 (B7-H3) to the pathogenesis of experimental SP-induced meningitis was investigated. Mice were challenged with the intracerebroventricular injection of serotype 3 SP with or without B7-H3. The clinical status of mice with SP-induced meningitis was examined by body weight loss and spontaneous motor activity with neurological scoring. Coronal brain sections were analyzed by counting Nissl-positive neurons and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells. Protein expression of neuron-specific enolase (NSE) and S100B in brain tissues was examined with immunohistochemical staining. All experiments were performed in a randomized and blinded setting. By the intracerebroventricular injection of SP suspension, a murine model of pneumococcal meningitis was successfully established. In this SP-induced meningitis model, B7-H3 deteriorated the clinical status, as manifested by a decreased neurological score and increased body weight loss. Following the B7-H3 challenge, the number of Nissl-positive cells decreased and TUNEL-stained positive cells increased in the brain tissues of mice with SP meningitis, which demonstrates the enhancement of neuronal necrosis and apoptosis, respectively. Protein expression of NSE was decreased, while that of S100B was increased. These in vivo findings indicate that B7-H3 aggravates brain injury during the pathological process of experimental SP-induced meningitis.

Can Valeriana officinalis root extract prevent early postoperative cognitive dysfunction after CABG surgery? A randomized, double-blind, placebo-controlled trial

RATIONALE

We hypothesized that valerian root might prevent cognitive dysfunction in coronary artery bypass graft (CABG) surgery patients through stimulating serotonin receptors and anti-inflammatory activity.

OBJECTIVES

The aim of this study was to evaluate the effect of Valeriana officinalis root extract on prevention of early postoperative cognitive dysfunction after on-pump CABG surgery.

METHODS

In a randomized, double-blind, placebo-controlled trial, 61 patients, aged between 30 and 70 years, scheduled for elective CABG surgery using cardiopulmonary bypass (CPB), were recruited into the study. Patients were randomly divided into two groups who received either one valerian capsule containing 530 mg of valerian root extract (1,060 mg/daily) or placebo capsule each 12 h for 8 weeks, respectively. For all patients, cognitive brain function was evaluated before the surgery and at 10-day and 2-month follow-up by Mini Mental State Examination (MMSE) test.

RESULTS

Mean MMSE score decreased from 27.03 ± 2.02 in the preoperative period to 26.52 ± 1.82 at the 10th day and then increased to 27.45 ± 1.36 at the 60th day in the valerian group. Conversely, its variation was reduced significantly after 60 days in the placebo group, 27.37 ± 1.87 at the baseline to 24 ± 1.91 at the 10th day, and consequently slightly increased to 24.83 ± 1.66 at the 60th day. Valerian prophylaxis reduced odds of cognitive dysfunction compared to placebo group (OR = 0.108, 95 % CI 0.022-0.545).

CONCLUSION

We concluded that, based on this study, the cognitive state of patients in the valerian group was better than that in the placebo group after CABG; therefore, it seems that the use of V. officinalis root extract may prevent early postoperative cognitive dysfunction after on-pump CABG surgery.