Sominone enhances neurite outgrowth and spatial memory mediated by the neurotrophic factor receptor, RET

Effect of ashwagandha (Withania somnifera) extract with Sominone (Somin-On™) to improve memory in adults with mild cognitive impairment: A randomized, double-blind, placebo-controlled study

BACKGROUND

Mild cognitive impairment (MCI) is a condition in which people have memory or thinking problems than other people of their age. This study evaluated the effectiveness and safety of ashwagandha extract standardized with Sominone (Somin-On™) in enhancing memory and cognitive functioning in adults with MCI.

METHODS

In this randomized double-blind, placebo-controlled pilot study, 40 subjects with MCI were randomized in a 1:1 ratio to receive either Somin-On™ (250 mg daily) or a placebo for 60 days. The outcome measures, improvement in memory and other cognitive functions after 30 and 60 days were assessed using Montreal Cognitive Assessment (MoCA); Mini-mental state examination (MMSE); Wechsler Memory Scale-III (WMS-III)); and Shepard mental rotation task.

RESULTS

Subjects treated with Somin-On™ showed significant improvements in immediate memory, general memory, working memory and visuospatial processing and the response assessed using WMS-III after 30 and 60 days outperforming the placebo group. Scores on the Shepard Mental Rotation test in Somin-On™ group showed a significant rise by 12.22% at 30 days and 31.67% at 60 days, from baseline. Significant improvement was observed with Somin-On™ in memory assessment scales viz. MoCA (7.83% at 30 days and 14.77% at 60 days, from baseline) and MMSE (9.26% at 30 days and 19.21% at 60 days, from baseline) compared to placebo group.

CONCLUSIONS

The supplementation of Somin-On™ is an effective therapy to improve the immediate, general and working memory, as well as cognitive functions like attention and information processing speed in adults with MCI.

Reactive Astrocytes Release GDNF to Promote Brain Recovery and Neuronal Survival Following Ischemic Stroke

Astrocytes are important glia cell type in the central nervous system. These cells can undergo transformation to a reactive state upon injury such as focal ischemic stroke (FIS). Reactive astrocytes are distinct from normal or homeostatic astrocytes in morphology, protein profiles and metabolic functions. Glial cell-derived neurotrophic factor (GDNF) was discovered as a potent survival neurotrophic factor for multiple subtypes of neurons and can be released from reactive astrocytes. In our previous study, we found that GDNF expression was upregulated in reactive astrocytes following ischemic stroke. Specific knock out of GDNF in reactive astrocytes exacerbated brain damage and motor deficits after ischemic stroke. Here, using in vitro and in vivo ischemia models, we investigated the effects of GDNF overexpression in astrocytes on neuronal survival and brain recovery after ischemia. We observed that astrocyte specific GDNF overexpression by viral transduction could decrease brain infarction and promote motor function recovery after photothrombosis (PT)-induced FIS. In addition, GDNF overexpression in astrocytes could increase the proliferation of reactive astrocytes and reduce oxidative stress after PT. Using the oxygen-glucose deprivation (OGD) model of cultured astrocytes, we confirmed that this ischemic insult could upregulate GDNF expression and increase its release to extracellular space. Transfection of GDNF DNA plasmid could further increase GDNF release after OGD. To further study the effects of reactive astrocytes-derived extracellular GDNF on neuronal survival after ischemia, cultured neurons subjected to OGD were exposed to astrocyte conditioned medium (ACM). The ACM collected from OGD subjected astrocyte culture could significantly reduce neuronal death, while neutralizing antibodies against GDNF and its receptors including GFRα1, RET and p-RET could suppress this beneficial effect. We also found that reactive astrocytes-derived GDNF could trigger the activation of RET receptors in cultured neurons and suppress neuronal mitochondrial fission and caspase-dependent cell apoptosis after OGD. Overall, our results indicate that reactive astrocytes-derived GDNF could play an important role in neuronal survival and functional recovery and underscore the non-cell autonomy underlying astrocyte-neuron interactions in brain repair after ischemic stroke.

Quantifying Withanolides in Plasma: Pharmacokinetic Studies and Analytical Methods

Withania somnifera (common name: ashwagandha; WS) is an Ayurvedic botanical that has become popular for its reputed effects on stress and insomnia. Research into the bioactive compounds responsible for the biological effects of WS has largely focused on withanolides, a group of steroidal lactones commonly found in the Solanaceae family. Until recently, however, it was unclear which, if any, withanolides were present in the plasma after the ingestion of WS products. The aim of this review is to summarize current knowledge regarding the plasma pharmacokinetics of withanolides found in WS and the analytical methods developed to detect them in plasma. Twenty studies (sixteen animal, four human) were identified in which isolated withanolides or withanolide-containing products were administered to animals or humans and quantified in plasma. Withanolides were commonly analyzed using reversed-phase liquid chromatography coupled to mass spectrometry. Plasma concentrations of withanolides varied significantly depending on the substance administered, withanolide dose, and route of administration. Plasma pharmacokinetics of withaferin A, withanolide A, withanolide B, withanoside IV, 12-deoxywithastramonolide, and withanone have been reported in rodents (Cmax range: 5.6-8410 ng/mL), while withaferin A, withanolide A, 12-deoxywithastramonolide, and withanoside IV pharmacokinetic parameters have been described in humans (Cmax range: 0.1-49.5 ng/mL).

GDNF facilitates cognitive function recovery following neonatal surgical-induced learning and memory impairment via activation of the RET pathway and modulation of downstream effectors PKMζ and Kalirin in rats

OBJECTIVE

The aim of this study is to elucidate the underlying mechanism through which glial cell line-derived neurotrophic factor (GDNF) improves cognitive deficits in adults resulting from neonatal surgical interventions.

METHODS

Newborn Sprague-Dawley rats, regardless of gender, were randomly allocated into seven groups on postnatal day 7 as follows (n=15): (1) Control group (not subjected to anesthesia, surgery, or any pharmaceutical interventions); (2) GDNF group (received intracerebroventricular injection of GDNF); (3) Surgery group (underwent right carotid artery exposure under anesthesia with 3 % sevoflurane); (4) Surgery plus GDNF group; (5) Surgery plus GDNF and type II JAK inhibitor NVP-BBT594 (BBT594) group (administered intraperitoneal injection of BBT594); (6) BBT group; and (7) Surgery plus BBT group. Starting from postnatal day 33, all rats underwent Barnes maze and fear conditioning tests, followed by decapitation under sevoflurane anesthesia for subsequent analyses. The left hemibrains underwent Golgi staining, while the right hemibrains were used for hippocampal protein extraction to assess Protein kinase Mζ (PKMζ) and Kalirin expression through western blotting.

RESULTS

GDNF demonstrated a mitigating effect on spatial learning and memory impairment, as well as context-related fear memory impairment, reductions in dendritic total lengths, and spinal density within the hippocampus induced by surgical intervention. Notably, all of these ameliorative effects of GDNF were reversed upon administration of the RET inhibitor BBT594. Additionally, GDNF alleviated the downregulation of protein expression of PKMζ and Kalirin in the hippocampus of rats subjected to surgery, subsequently reversed by BBT594.

CONCLUSION

The effective impact of GDNF on learning and memory impairment caused by surgical intervention appears to be mediated through the RET pathway. Moreover, GDNF may exert its influence by upregulating the expression of PKMζ and Kalirin, consequently enhancing the development of dendrites and dendritic spines.

Withania somnifera (Ashwagandha) Improves Spatial Memory, Anxiety and Depressive-like Behavior in the 5xFAD Mouse Model of Alzheimer's Disease

Withania somnifera (WS), also known as ashwagandha, is a popular botanical supplement used to treat various conditions including memory loss, anxiety and depression. Previous studies from our group showed an aqueous extract of WS root (WSAq) enhances cognition and alleviates markers for depression in Drosophila. Here, we sought to confirm these effects in the 5xFAD mouse model of β-amyloid (Aβ) accumulation. Six- to seven-month-old male and female 5xFAD mice were treated with WSAq in their drinking water at 0 mg/mL, 0.5 mg/mL or 2.5 mg/mL for four weeks. In the fourth week of treatment, spatial memory, anxiety and depressive-like symptoms were evaluated. At the conclusion of behavioral testing, brain tissue was harvested, immunohistochemistry was performed, and the cortical expression of antioxidant response genes was evaluated. Both concentrations of WSAq improved spatial memory and reduced depressive and anxiety-related behavior. These improvements were accompanied by a reduction in Aβ plaque burden in the hippocampus and cortex and an attenuation of activation of microglia and astrocytes. Antioxidant response genes were upregulated in the cortex of WSAq-treated mice. Oral WSAq treatment could be beneficial as a therapeutic option in AD for improving disease pathology and behavioral symptoms. Future studies focused on dose optimization of WSAq administration and further assessment of the mechanisms by which WSAq elicits its beneficial effects will help inform the clinical potential of this promising botanical therapy.

Withania somnifera (L.) Dunal, a Potential Source of Phytochemicals for Treating Neurodegenerative Diseases: A Systematic Review

Withania somnifera (L.) Dunal is a medicinal plant belonging to the traditional Indian medical system, showing various therapeutic effects such as anti-cancer, anti-inflammatory, anti-microbial, anti-diabetic, and hepatoprotective activity. Of great interest is W. somnifera's potential beneficial effect against neurodegenerative diseases, since the authorized medicinal treatments can only delay disease progression and provide symptomatic relief and are not without side effects. A systematic search of PubMed and Scopus databases was performed to identify preclinical and clinical studies focusing on the applications of W. somnifera in preventing neurodegenerative diseases. Only English articles and those containing the keywords (Withania somnifera AND "neurodegenerative diseases", "neuroprotective effects", "Huntington", "Parkinson", "Alzheimer", "Amyotrophic Lateral Sclerosis", "neurological disorders") in the title or abstract were considered. Reviews, editorials, letters, meta-analyses, conference papers, short surveys, and book chapters were not considered. Selected articles were grouped by pathologies and summarized, considering the mechanism of action. The quality assessment and the risk of bias were performed using the Cochrane Handbook for Systematic Reviews of Interventions checklist. This review uses a systematic approach to summarize the results from 60 investigations to highlight the potential role of W. somnifera and its specialized metabolites in treating or preventing neurodegenerative diseases.

Current Naturopathy to Combat Alzheimer's Disease

Neurodegeneration is the progressive loss of structure or function of neurons, which may ultimately involve cell death. The most common neurodegenerative disorder in the brain happens with Alzheimer's disease (AD), the most common cause of dementia. It ultimately leads to neuronal death, thereby impairing the normal functionality of the central or peripheral nervous system. The onset and prevalence of AD involve heterogeneous etiology, either in terms of genetic predisposition, neurometabolomic malfunctioning, or lifestyle. The worldwide relevancies are estimated to be over 45 million people. The rapid increase in AD has led to a concomitant increase in the research work directed towards discovering a lucrative cure for AD. The neuropathology of AD comprises the deficiency in the availability of neurotransmitters and important neurotrophic factors in the brain, extracellular betaamyloid plaque depositions, and intracellular neurofibrillary tangles of hyperphosphorylated tau protein. Current pharmaceutical interventions utilizing synthetic drugs have manifested resistance and toxicity problems. This has led to the quest for new pharmacotherapeutic candidates naturally prevalent in phytochemicals. This review aims to provide an elaborative description of promising Phyto component entities having activities against various potential AD targets. Therefore, naturopathy may combine with synthetic chemotherapeutics to longer the survival of the patients.

Therapeutic roles of plants for 15 hypothesised causal bases of Alzheimer's disease

Alzheimer's disease (AD) is progressive and ultimately fatal, with current drugs failing to reverse and cure it. This study aimed to find plant species which may provide therapeutic bioactivities targeted to causal agents proposed to be driving AD. A novel toolkit methodology was employed, whereby clinical symptoms were translated into categories recognized in ethnomedicine. These categories were applied to find plant species with therapeutic effects, mined from ethnomedical surveys. Survey locations were mapped to assess how this data is at risk. Bioactivities were found of therapeutic relevance to 15 hypothesised causal bases for AD. 107 species with an ethnological report of memory improvement demonstrated therapeutic activity for all these 15 causal bases. The majority of the surveys were found to reside within biodiversity hotspots (centres of high biodiversity under threat), with loss of traditional knowledge the most common threat. Our findings suggest that the documented plants provide a large resource of AD therapeutic potential. In demonstrating bioactivities targeted to these causal bases, such plants may have the capacity to reduce or reverse AD, with promise as drug leads to target multiple AD hallmarks. However, there is a need to preserve ethnomedical knowledge, and the habitats on which this knowledge depends.

Phytotherapeutics against Alzheimer's Disease: Mechanism, Molecular Targets and Challenges for Drug Development

Alzheimer's disease is inflating worldwide and is combatted by only a few approved drugs. At best, these drugs treat symptomatic conditions by targeting cholinesterase and N-methyl- D-aspartate receptors. Most of the clinical trials in progress are focused on developing disease-modifying agents that aim at single targets. The 'one drug-one target' approach is failing in the case of Alzheimer's disease due to its labyrinth etiopathogenesis. Traditional medicinal systems like Ayurveda use a holistic approach encompassing the legion of medicinal plants exhibiting multimodal activity. Recent advances in high-throughput technologies have catapulted the research in the arena of Ayurveda, specifically in identifying plants with potent anti-Alzheimer's disease properties and their phytochemical characterization. Nonetheless, clinical trials of very few herbal medicines are in progress. This review is a compendium of Indian plants and ayurvedic medicines against Alzheimer's disease and their paraphernalia. A record of 230 plants that are found in India with anti-Alzheimer's disease potential and about 500 phytochemicals from medicinal plants have been solicited with the hope of exploring the unexplored. Further, the molecular targets of phytochemicals isolated from commonly used medicinal plants, such as Acorus calamus, Bacopa monnieri, Convolvulus pluricaulis, Tinospora cordifolia and Withania somnifera, have been reviewed with respect to their multidimensional property, such as antioxidant, anti-inflammation, anti-aggregation, synaptic plasticity modulation, cognition, and memory-enhancing activity. In addition, the strengths and challenges in ayurvedic medicine that limit its use as mainstream therapy are discussed, and a framework for the development of herbal medicine has been proposed.

Chinese nutraceuticals and physical activity; their role in neurodegenerative tauopathies

The onset of neurodegenerative disease has not only been a major cause of scientific worry, but of economic burden to the health system. This condition has been further attributed to mis-stability, deletion or mutation of tau protein, causing the onset of Corticobasal degeneration, Pick's diseases, Progressive supranuclear palsy, Argyrophilic grains disease, Alzheimer's diseases etc. as scientifically renowned. This is mainly related to dysregulation of translational machinery, upregulation of proinflammatory cytokines and inhibition of several essential cascades such as ERK signaling cascade, GSK3β, CREB, and PKA/PKB (Akt) signaling cascades that enhances protein processing, normal protein folding, cognitive function, and microtubule associated tau stability. Administration of some nutrients and/or bioactive compounds has a high tendency to impede tau mediated inflammation at neuronal level. Furthermore, prevention and neutralization of protein misfolding through modulation of microtubule tau stability and prevention of protein misfolding is by virtue few of the numerous beneficial effects of physical activity. Of utmost important in this study is the exploration of promising bioactivities of nutraceuticals found in china and the ameliorating potential of physical activity on tauopathies, while highlighting animal and in vitro studies that have been investigated for comprehensive understanding of its potential and an insight into the effects on human highly probable to tau mediated neurodegeneration.

Indian Medicinal Herbs and Formulations for Alzheimer's Disease, from Traditional Knowledge to Scientific Assessment

Cognitive impairment, associated with ageing, stress, hypertension and various neurodegenerative disorders including Parkinson's disease and epilepsy, is a major health issue. The present review focuses on Alzheimer's disease (AD), since it is the most important cause of cognitive impairment. It is characterized by progressive memory loss, language deficits, depression, agitation, mood disturbances and psychosis. Although the hallmarks of AD are cholinergic dysfunction, β-amyloid plaques and neurofibrillary tangle formation, it is also associated with derangement of other neurotransmitters, elevated levels of advanced glycation end products, oxidative damage, neuroinflammation, genetic and environmental factors. On one hand, this complex etiopathology makes a response to commonly used drugs such as donepezil, rivastigmine, galantamine and memantine less predictable and often unsatisfactory. On the other hand, it supports the use of herbal medicines due to their nonspecific antioxidant and anti-inflammatory activity and specific cholinesterase inhibitory activity. The popularity of herbal medicines is also increasing due to their perceived effectiveness, safety and affordability. In the present article, the experimental and clinical evidence have been reviewed for various Indian herbal medicines such as Centella asiatica, Bacopa monnieri, Curcuma longa, Clitoria ternatea, Withania somnifera, Celastrus paniculatus, Evolvulus alsinoides, Desmodium gangeticum, Eclipta alba, Moringa oleifera and Convolvulus pluricaulis, which have shown potential in cognitive impairment. Some commonly available herbal formulations for memory impairment in India have also been reviewed.

Role of nutraceuticals in cognition during aging and related disorders

Cognitive abilities are compromised with advancing age posing a great risk for the development of dementia and other related brain disorders. Genetic susceptibility as well as environmental exposures determine the fate of cognitive aging and its transition to pathological states. Emerging epidemiological and observational studies have revealed the importance of lifestyle factors including dietary patterns and nutritional intake in the maintenance of cognitive health and reducing the risk of neurodegenerative disorders. In this context, nutraceutical interventions have gained considerable attention in preventing age-related cognitive deficits and counteracting pathological processes. Nutraceuticals include dietary plants and derivatives, food supplements and processed foods with nutritional and pharmaceutical values. The present review highlights the importance of nutraceuticals in attenuating cognitive aging and its progression to dementia, with specific emphasis on chemical constituents, neurocognitive properties and mechanism of action.

Withania somnifera L.: Insights into the phytochemical profile, therapeutic potential, clinical trials, and future prospective

Withania somnifera L. is a multipurpose medicinal plant of family Solanaceae occurring abundantly in sub-tropical regions of the world. The folk healers used the plant to treat several diseases such as fever, cancer, asthma, diabetes, ulcer, hepatitis, eyesores, arthritis, heart problems, and hemorrhoids. The plant is famous for the anti-cancerous activity, low back pain treatment, and muscle strengthening, which may be attributed to the withanolide alkaloids. W. somnifera is also rich in numerous valued secondary metabolites such as steroids, alkaloids, flavonoids, phenolics, saponins, and glycosides. A wide range of preclinical trials such as cardioprotective, anticancer, antioxidant, antibacterial, antifungal, anti-inflammatory, hepatoprotective, anti-depressant, and hypoglycemic have been attributed to various parts of the plant. Different parts of the plant have also been evaluated for the clinical trials such as male infertility, obsessive-compulsive disorder, antianxiety, bone and muscle strengthening potential, hypolipidemic, and antidiabetic. This review focuses on folk medicinal uses, phytochemistry, pharmacological, and nutrapharmaceutical potential of the versatile plant.

Natural Medicines and Their Underlying Mechanisms of Prevention and Recovery from Amyloid Β-Induced Axonal Degeneration in Alzheimer's Disease

In Alzheimer's disease (AD), amyloid β (Aβ) induces axonal degeneration, neuronal network disruption, and memory impairment. Although many candidate drugs to reduce Aβ have been clinically investigated, they failed to recover the memory function in AD patients. Reportedly, Aβ deposition occurred before the onset of AD. Once neuronal networks were disrupted by Aβ, they could hardly be recovered. Therefore, we speculated that only removal of Aβ was not enough for AD therapy, and prevention and recovery from neuronal network disruption were also needed. This review describes the challenges related to the condition of axons for AD therapy. We established novel in vitro models of Aβ-induced axonal degeneration. Using these models, we found that several traditional medicines and their constituents prevented or helped recover from Aβ-induced axonal degeneration. These drugs also prevented or helped recover from memory impairment in in vivo models of AD. One of these drugs ameliorated memory decline in AD patients in a clinical study. These results indicate that prevention and recovery from axonal degeneration are possible strategies for AD therapy.

Dysfunction of the Microbiota-Gut-Brain Axis in Neurodegenerative Disease: The Promise of Therapeutic Modulation With Prebiotics, Medicinal Herbs, Probiotics, and Synbiotics

Recent data suggest gut microbiota dysbiosis as a contributing factor in neurodegenerative diseases, such as Parkinson's Disease (PD) and Alzheimer's Disease (AD), and these pathologies may manifest via the microbiota-gut-brain-axis, which comprises bidirectional communication through neuroimmune, neuroendocrine, and direct neural pathways such as the vagus nerve. Preclinical and human clinical trial data reveal exciting potential for novel treatment targets and therapeutic modulation with prebiotics, medicinal herbs, probiotics, and synbiotics in health, aging, and neurodegeneration and are reviewed here. While greater insights and characterization of the microbiota-gut-brain axis have been revealed over the past decade, salient questions related to the pathology, pathogenesis and clinical treatment of the axis in the context of both health and neurodegenerative disease remain and are discussed in this review. Future directions such as additional well-controlled, large scale, longitudinal human clinical trials are urgently needed to further elucidate both mechanism and therapeutic opportunity in health, neurological disease, and disease subpopulations to ensure that the next decade ushers the dawn of targeted therapeutic modulation of the microbiota-gut-brain axis.

Nootropic and Anti-Alzheimer's Actions of Medicinal Plants: Molecular Insight into Therapeutic Potential to Alleviate Alzheimer's Neuropathology

Medicinal plants are the backbone of modern medicine. In recent times, there is a great urge to discover nootropic medicinal plants to reverse cognitive dysfunction owing to their less adverse effects. Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by the inevitable loss of cognitive function, memory and language impairment, and behavioral disturbances, which turn into gradually more severe. Alzheimer's has no current cure, but symptomatic treatments are available and research continues. The number of patients suffering from AD continues to rise and today, there is a worldwide effort under study to find better ways to alleviate Alzheimer's pathogenesis. In this review, the nootropic and anti-Alzheimer's potentials of 6 medicinal plants (i.e., Centella asiatica, Clitoria ternatea, Crocus sativus, Terminalia chebula, Withania somnifera, and Asparagus racemosus) were explored through literature review. This appraisal focused on available information about neuroprotective and anti-Alzheimer's use of these plants and their respective bioactive compounds/metabolites and associated effects in animal models and consequences of its use in human as well as proposed molecular mechanisms. This review progresses our existing knowledge to reveal the promising linkage of traditional medicine to halt AD pathogenesis. This analysis also avowed a new insight to search the promising anti-Alzheimer's drugs.

In vitro screening of neuroprotective activity of Indian medicinal plant Withania somnifera

Canine cognitive dysfunction (CCD) is an age-dependent neurodegenerative condition characterised by changes in decline in learning and memory patterns. The neurodegenerative features of CCD in ageing dogs and cats are similar to human ageing and Alzheimer's disease (AD). Discovering neuroprotective disease-modifying therapies against CCD and AD is a major challenge. Strong evidence supports the role of amyloid β peptide deposition and oxidative stress in the pathophysiology of CCD and AD. In both the human and canine brain, oxidative damage progressively increases with age. Dietary antioxidants from natural sources hold a great promise in halting the progression of CCD and AD. Withania somnifera (WS), an Ayurvedic tonic medicine, also known as ‘Indian ginseng’ or ashwagandha has a long history of use in memory-enhancing therapy but there is a dearth of studies on its neuroprotective effects. The objective of this study was to investigate whether WS extract can protect against Aβ peptide- and acrolein-induced toxicity. We demonstrated that treatment with WS extract significantly protected the human neuroblastoma cell line SK-N-SH against Aβ peptide and acrolein in various cell survival assays. Furthermore, treatment with WS extract significantly reduced the generation of reactive oxygen species in SK-N-SH cells. Finally, our results showed that WS extract is also a potent inhibitor of acetylcholinesterase activity. Thus, our initial findings indicate that WS extract may act as an antioxidant and cholinergic modulator and may have beneficial effects in CCD and AD therapy.

Withania somnifera Reverses Transactive Response DNA Binding Protein 43 Proteinopathy in a Mouse Model of Amyotrophic Lateral Sclerosis/Frontotemporal Lobar Degeneration

Abnormal cytoplasmic mislocalization of transactive response DNA binding protein 43 (TARDBP or TDP-43) in degenerating neurons is a hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U). Our previous work suggested that nuclear factor kappa B (NF-κB) may constitute a therapeutic target for TDP-43-mediated disease. Here, we investigated the effects of root extract of Withania somnifera (Ashwagandha), an herbal medicine with anti-inflammatory properties, in transgenic mice expressing a genomic fragment encoding human TDP-43A315T mutant. Ashwagandha extract was administered orally to hTDP-43A315T mice for a period of 8 weeks starting at 64 and 48 weeks of age for males and females, respectively. The treatment of hTDP-43A315T mice ameliorated their motor performance on rotarod test and cognitive function assessed by the passive avoidance test. Microscopy examination of tissue samples revealed that Ashwagandha treatment of hTDP-43A315T mice improved innervation at neuromuscular junctions, attenuated neuroinflammation, and reduced NF-κB activation. Remarkably, Ashwagandha treatment reversed the cytoplasmic mislocalization of hTDP-43 in spinal motor neurons and in brain cortical neurons of hTDP-43A315T mice and it reduced hTDP-43 aggregation. In vitro evidence is presented that the neuronal rescue of TDP-43 mislocalization may be due to the indirect effect of factors released from microglial cells exposed to Ashwagandha. These results suggest that Ashwagandha and its constituents might represent promising therapeutics for TDP-43 proteinopathies.

New Age Therapy for Alzheimer's Disease by Neuronal Network Reconstruction

Alzheimer's disease (AD) is a recognized incurable neurodegenerative disorder. Clinically prescribed medicines for AD are expected to bring about only slight symptomatic improvement or a delay of its progression. Another strategy, amyloid β (Aβ) lowing agents, has not been successful at memory improvement. We have hypothesized that an improvement in cognitive function requires the construction of neuronal networks, including neurite regeneration and synapse formation; therefore, we have been exploring candidates for radical anti-AD drugs that can restore Aβ-induced neurite atrophy and memory impairment. Our studies found several promising drug candidates that may improve memory dysfunction in AD model mice. The main activity of these drugs is the restoration of damaged axons. Focusing on candidates based on the recovery of neurite atrophy in vitro certainly leads to positive effects on memory improvement also in vivo. This suggests that neuronal network reconstruction may importantly relate to functional recovery in the brain. When identifying the signaling mechanisms of exogenous compounds like natural medicine-derived constituents, molecules directly activated by the compound are hard to be identified. However, the drug affinity responsive target stability (DARTS) analysis may pave the way to an approach to determine the initial molecule of the signaling pathway. Exploring new drug candidates and clarifying their signaling pathways directly relating to neuronal network reconstruction may provide promising therapeutic strategies with which to overcome AD.

Withania somnifera Improves Ischemic Stroke Outcomes by Attenuating PARP1-AIF-Mediated Caspase-Independent Apoptosis

Withania somnifera (WS), popularly known as "Ashwagandha" has been used for centuries as a nerve tonic. Its protective effect has been elucidated in many neurodegenerative pathologies, although there is a paucity of data regarding its effects in ischemic stroke. We examined the neuroprotective properties of an aqueous extract of WS in both pre- and poststroke treatment regimens in a mouse model of permanent distal middle cerebral artery occlusion (pMCAO). WS (200 mg/kg) improved functional recovery and significantly reduced the infarct volume in mice, when compared to those treated with vehicle, in both paradigms. We investigated the protective mechanism/s induced by WS using brain cortices by testing its ability to modulate the expression of key proteins in the ischemic-apoptotic cascade. The Western blots and immunofluorescence analyses of mice cortices revealed that WS upregulated the expression of hemeoxygenase 1 (HO1) and attenuated the expression of the proapoptotic protein poly (ADP-ribose) polymerase-1 (PARP1) via the PARP1-AIF pathway, thus preventing the nuclear translocation of apoptosis-inducing factor (AIF), and subsequent apoptosis. Semaphorin-3A (Sema3A) expression was reduced in WS-treated group, whereas Wnt, pGSK3β, and pCRMP2 expression levels were virtually unaltered. These results indicate the interplay of antioxidant-antiapoptic pathways and the possible involvement of angiogenesis in the protective mechanism of WS while emphasizing the noninvolvement of one of the prime pathways of neurogenesis. Our results suggest that WS could be a potential prophylactic as well as a therapeutic agent aiding stroke repair, and that part of its mechanism could be attributed to its antiapoptotic and antioxidant properties.

Nootropic potential of Ashwagandha leaves: Beyond traditional root extracts

Rapidly increasing aging population and environmental stressors are the two main global concerns of the modern society. These have brought in light rapidly increasing incidence of a variety of pathological conditions including brain tumors, neurodegenerative & neuropsychiatric disorders, and new challenges for their treatment. The overlapping symptoms, complex etiology and lack of full understanding of the brain structure and function to-date further complicate these tasks. On the other hand, several herbal reagents with a long history of their use have been asserted to possess neurodifferentiation, neuroregenerative and neuroprotective potentials, and hence been recommended as supplement to enhance and maintain brain health and function. Although they have been claimed to function by holistic approach resulting in maintaining body homeostasis and brain health, there are not enough laboratory studies in support to these and mechanism(s) of such beneficial activities remain largely undefined. One such herb is Ashwagandha, also called "Queen of Ayurveda" for its popular use in Indian traditional home medicine because of its extensive benefits including anticancer, anti-stress and remedial potential for aging and neurodegenerative pathologies. However, active principles and underlying mechanism(s) of action remain largely unknown. Here we provide a review on the effects of Ashwagandha extracts and active principles, and underlying molecular mechanism(s) for brain pathologies. We highlight our findings on the nootropic potential of Ashwagandha leaves. The effects of Ashwagandha leaf extracts are multidimensional ranging from differentiation of neuroblastoma and glioma cells, reversal of Alzheimer and Parkinson's pathologies, protection against environmental neurotoxins and enhancement of memory.

Withania somnifera alleviates parkinsonian phenotypes by inhibiting apoptotic pathways in dopaminergic neurons

Maneb (MB) and paraquat (PQ) are environmental toxins that have been experimentally used to induce selective damage of dopaminergic neurons leading to the development of Parkinson's disease (PD). Although the mechanism of this selective neuronal toxicity in not fully understood, oxidative stress has been linked to the pathogenesis of PD. The present study investigates the mechanisms of neuroprotection elicited by Withania somnifera (Ws), a herb traditionally recognized by the Indian system of medicine, Ayurveda. An ethanolic root extract of Ws was co-treated with the MB-PQ induced mouse model of PD and was shown to significantly rescue canonical indicators of PD including compromised locomotor activity, reduced dopamine in the substantia nigra and various aspects of oxidative damage. In particular, Ws reduced the expression of iNOS, a measure of oxidative stress. Ws also significantly improved the MB + PQ mediated induction of a pro-apoptotic state by reducing Bax and inducing Bcl-2 protein expression, respectively. Finally, Ws reduced expression of the pro-inflammatory marker of astrocyte activation, GFAP. Altogether, the present study suggests that Ws treatment provides nigrostriatal dopaminergic neuroprotection against MB-PQ induced Parkinsonism by the modulation of oxidative stress and apoptotic machinery possibly accounting for the behavioural effects.

Glioprotective effects of Ashwagandha leaf extract against lead induced toxicity

Withania somnifera (Ashwagandha), also known as Indian Ginseng, is a well-known Indian medicinal plant due to its antioxidative, antistress, antigenotoxic, and immunomodulatory properties. The present study was designed to assess and establish the cytoprotective potential of Ashwagandha leaf aqueous extract against lead induced toxicity. Pretreatment of C6 cells with 0.1% Ashwagandha extract showed cytoprotection against 25  μM to 400 μM concentration of lead nitrate. Further pretreatment with Ashwagandha extract to lead nitrate exposed cells (200  μM) resulted in normalization of glial fibrillary acidic protein (GFAP) expression as well as heat shock protein (HSP70), mortalin, and neural cell adhesion molecule (NCAM) expression. Further, the cytoprotective efficacy of Ashwagandha extract was studied in vivo. Administration of Ashwagandha extract provided significant protection to lead induced altered antioxidant defense that may significantly compromise normal cellular function. Ashwagandha also provided a significant protection to lipid peroxidation (LPx) levels, catalase, and superoxide dismutase (SOD) but not reduced glutathione (GSH) contents in brain tissue as well as peripheral organs, liver and kidney, suggesting its ability to act as a free radical scavenger protecting cells against toxic insult. These results, thus, suggest that Ashwagandha water extract may have the potential therapeutic implication against lead poisoning.

A novel compound, denosomin, ameliorates spinal cord injury via axonal growth associated with astrocyte-secreted vimentin

BACKGROUND AND PURPOSE

In the spinal cord injury (SCI) axon regeneration is inhibited by the glial scar, which contains reactive astrocytes that secrete inhibitory chondroitin sulphate proteoglycan (CSPG). We previously reported that a novel compound, denosomin, promotes axonal growth under degenerative conditions in cultured cortical neurons. In this study, we investigated the effects of denosomin on functional recovery in SCI mice and elucidated the mechanism though which denosomin induces axonal growth in the injured spinal cord.

EXPERIMENTAL APPROACH

Denosomin was administered p.o. for 7 or 14 days to contusion mice. Behavioural evaluations and immunohistochemistry were done. Primary cultured cortical neurons and astrocytes were treated with denosomin to investigate the mechanism of axonal growth facilitation.

KEY RESULTS

Denosomin improved hind limb motor dysfunction and axonal growth, especially in the 5-HT-positive tracts across the scar and increased the density of astrocytes. Denosomin increased astrocyte proliferation, inhibited astrocytic death and increased the expression and secretion of vimentin in cultured astrocytes. Furthermore, vimentin increased axonal outgrowth in cultured neurons, even in the presence of inhibitory CSPG. Denosomin increased the number of vimentin-expressing astrocytes inside glial scars of SCI mice, and 5-HT-positive axonal growth occurred in a vimentin-associated manner.

CONCLUSION AND IMPLICATIONS

Denosomin increased the ratio of astrocytes that secrete vimentin as an axonal growth facilitator, which, we propose enhances axonal growth beyond the glial scar and promotes functional recovery in SCI mice. This study is the first to demonstrate this novel role of vimentin in SCI and drug-mediated modification of the inhibitory property of reactive astrocytes.

Neuroprotective mechanisms of the standardized extract of Bacopa monniera in a paraquat/diquat-mediated acute toxicity

Parkinson's disease (PD) is one of the most common age related neurodegenerative disease and affects millions of people worldwide. Strong evidence suggests a role for oxidative stress and mitochondrial dysfunctions in the pathogenesis of PD. Recent epidemiologic and toxicological studies have shown that environmental factors, especially herbicides such as paraquat and diquat represent one of the primary classes of neurotoxic agents associated with PD. The objective of our study was to investigate the neuroprotective effects of the standardized extract of Bacopa monniera (BM) against paraquat/diquat-induced toxicity and to elucidate the mechanisms underlying this protection. Our results showed that a pre-treatment with the BM extract, from 20.0μg/ml, protected the rat dopaminergic PC12 cell line against paraquat/diquat-induced toxicity in various cell survival assays. We demonstrated that BM pre-treatment, from 5.0μg/ml, could prevent the generation of intracellular reactive oxygen species (ROS), decreased mitochondrial superoxide levels and depolarized the mitochondria. BM pre-treatment also increased tyrosine hydroxylase (TH) levels and antioxidant defense systems such as γ-glutamylcysteine synthetase (γ-GCS) and thioredoxin1 (Trx1) levels. Furthermore, BM pre-treatment prevented the activation of Akt and heat shock protein90 (HSP90) proteins. Thus, our findings demonstrated that BM can protect PC12 cells through modulating cellular redox pathways which are altered in PD and could have a therapeutic application in the prevention of PD.

Epimedium koreanum Extract and Its Constituent Icariin Improve Motor Dysfunction in Spinal Cord Injury

Although cell transplantation strategies for spinal cord injury (SCI) using sources such as iPS cells and neural stem cells are focused as expectative therapies for SCI, the possibility of medication as more accessible and practical way should not be given up. We, therefore, aimed to develop medical sources for SCI. In this paper, we evaluated effects of a famous tonic herb, Epimedium koreanum, on motor dysfunction in spinal cord injury (SCI). The spinal cord was injured by contusion after laminectomy at T10 level. Oral administration of the methanol extract of E. koreanum significantly enhanced hindlimb function in SCI mice by short period treatment (for initial 3 days) and chronic treatment (21 days), although chronic treatment recovered the function more potently. Since it is well known that icariin is the major constituent in E. koreanum, icariin was administered orally to SCI mice for initial 3 days. Motor dysfunction was ameliorated by icariin treatment similarly to the methanol extract of E. koreanum. This paper is the first report to indicate E. koreanum is effective for recovery of motor function in SCI, and at least icariin is an active constituent.

Water extract from the leaves of Withania somnifera protect RA differentiated C6 and IMR-32 cells against glutamate-induced excitotoxicity

Glutamate neurotoxicity has been implicated in stroke, head trauma, multiple sclerosis and neurodegenerative disorders. Search for herbal remedies that may possibly act as therapeutic agents is an active area of research to combat these diseases. The present study was designed to investigate the neuroprotective role of Withania somnifera (Ashwagandha), also known as Indian ginseng, against glutamate induced toxicity in the retinoic acid differentiated rat glioma (C6) and human neuroblastoma (IMR-32) cells. The neuroprotective activity of the Ashwagandha leaves derived water extract (ASH-WEX) was evaluated. Cell viability and the expression of glial and neuronal cell differentiation markers was examined in glutamate challenged differentiated cells with and without the presence of ASH-WEX. We demonstrate that RA-differentiated C6 and IMR-32 cells, when exposed to glutamate, undergo loss of neural network and cell death that was accompanied by increase in the stress protein HSP70. ASH-WEX pre-treatment inhibited glutamate-induced cell death and was able to revert glutamate-induced changes in HSP70 to a large extent. Furthermore, the analysis on the neuronal plasticity marker NCAM (Neural cell adhesion molecule) and its polysialylated form, PSA-NCAM revealed that ASH-WEX has therapeutic potential for prevention of neurodegeneration associated with glutamate-induced excitotoxicty.

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

Background

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

Methodology/Principal Findings

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

Conclusion

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

Icariin improves memory impairment in Alzheimer's disease model mice (5xFAD) and attenuates amyloid β-induced neurite atrophy

Essential therapeutic drugs for Alzheimer's disease (AD) have not been developed. Since the neuritic atrophy leading to synaptic losses is one of the critical causes of memory impairment in AD, the effects of several constituents in tonic herbal medicines on neuritic atrophy and memory deficits have been studied. The present study investigated the effects of icariin, a main constituent in Epimedii Herba, a well known tonic crude drug, in an in vitro AD model and transgenic mouse AD model (5xFAD). Amyloid β(1-42)-induced atrophies of axons and dendrites were restored by post-treatment with icariin in rat cortical neurons. Administration of icariin for 8 days (p.o.) improved spatial memory impairment in 5xFAD mice. These novel findings suggest that icariin may improve memory dysfunction in AD and have a potential to extend neurites even when amyloid β-induced neurite atrophy has already occurred.