Therapeutic potential of curcumin on the cognitive decline in animal models of Alzheimer's disease: a systematic review and meta-analysis.

Curcumin, a polyphenol derived from the herb turmeric, has emerged as a prospective potential therapy in the treatment of Alzheimer's disease (AD). However, the efficacy of curcumin treatment in improving cognitive decline caused controversy recently. We aimed to systematically review the effect of curcumin on cognitive impairment in an animal model of AD. We conducted an exhaustive database search of related studies. Two investigators identified studies and independently extracted data. Stratified meta-analyses and meta-regression analyses were carried out to explore the sources of heterogeneity. Publication bias was assessed using funnel plots and Egger's test. Our systematic review included 33 articles. A meta-analysis of 29 publications showed that curcumin exerts significant positive effects on cognitive performance. For acquisition, the global estimated effect of curcumin was - 2.027 (95% CI - 2.435 to - 1.619, p < 0.001); for retention, the global estimated effect of curcumin was 1.606 (95% CI 1.101 to 2.111, p < 0.001). The stratified meta-analysis demonstrated that an increased effect size depended on diverse study characteristics. Additionally, publication bias was detected. We conclude that curcumin may reduce cognitive deficits in experimental AD. Furthermore, we emphasize that additional well-designed and well-reported animal studies are needed to inform further clinical studies.

Mechanisms of multi-omics and network pharmacology to explain traditional chinese medicine for vascular cognitive impairment: A narrative review.

BACKGROUND: The term "vascular cognitive impairment" (VCI) describes various cognitive conditions that include vascular elements. It increases the risk of morbidity and mortality in the elderly population and is the most common cognitive impairment associated with cerebrovascular disease. Understanding the etiology of VCI may aid in identifying approaches to target its possible therapy for the condition. Treatment of VCI has focused on vascular risk factors. There are no authorized conventional therapies available right now. The medications used to treat VCI are solely approved for symptomatic relief and are not intended to prevent or slow the development of VCI. PURPOSE: The function of Chinese medicine in treating VCI has not yet been thoroughly examined. This review evaluates the preclinical and limited clinical evidence to comprehend the "multi-component, multi-target, multi-pathway" mechanism of Traditional Chinese medicine (TCM). It investigates the various multi-omics approaches in the search for the pathological mechanisms of VCI, as well as the new research strategies, in the hopes of supplying supportive evidence for the clinical treatment of VCI. METHODS: This review used the Preferred Reporting Items for Preferred reporting items for systematic reviews and meta-analyses (PRISMA) statements. Using integrated bioinformatics and network pharmacology approaches, a thorough evaluation and analysis of 25 preclinical studies published up to July 1, 2023, were conducted to shed light on the mechanisms of TCM for vascular cognitive impairment. The studies for the systematic review were located using the following databases: PubMed, Web of Science, Scopus, Cochrane, and ScienceDirect. RESULTS: We discovered that the multi-omics analysis approach would hasten the discovery of the role of TCM in the treatment of VCI. It will explore components, compounds, targets, and pathways, slowing the progression of VCI from the perspective of inhibiting oxidative stress, stifling neuroinflammation, increasing cerebral blood flow, and inhibiting iron deposition by a variety of molecular mechanisms, which have significant implications for the treatment of VCI. CONCLUSION: TCM is a valuable tool for developing dementia therapies, and further research is needed to determine how TCM components may affect the operation of the neurovascular unit. There are still some limitations, although several research have offered invaluable resources for searching for possible anti-dementia medicines and treatments. To gain new insights into the molecular mechanisms that precisely modulate the key molecules at different levels during pharmacological interventions-a prerequisite for comprehending the mechanism of action and determining the potential therapeutic value of the drugs-further research should employ more standardized experimental methods as well as more sophisticated science and technology. Given the results of this review, we advocate integrating chemical and biological component analysis approaches in future research on VCI to provide a more full and objective assessment of the standard of TCM. With the help of bioinformatics, a multi-omics analysis approach will hasten the discovery of the role of TCM in the treatment of VCI, which has significant implications for the treatment of VCI.

Roles of Omega-3 Polyunsaturated Fatty Acids in Managing Cognitive Impairment in Chronic Obstructive Pulmonary Disease: A Review.

Chronic obstructive pulmonary disease (COPD) contributes significantly to the death of people worldwide, especially the elderly. An essential feature of COPD is pulmonary inflammation, which results from long-term exposure to noxious substances from cigarette smoking and other environmental pollutants. Pulmonary inflammatory mediators spill over to the blood, leading to systemic inflammation, which is believed to play a significant role in the onset of a host of comorbidities associated with COPD. A substantial comorbidity of concern in COPD patients that is often overlooked in COPD management is cognitive impairment. The exact pathophysiology of cognitive impairment in COPD patients remains a mystery; however, hypoxia, oxidative stress, systemic inflammation, and cerebral manifestations of these conditions are believed to play crucial roles. Furthermore, the use of medications to treat cognitive impairment symptomatology in COPD patients has been reported to be associated with life-threatening adverse effects, hence the need for alternative medications with reduced side effects. In this Review, we aim to discuss the impact of cognitive impairment in COPD management and the potential mechanisms associated with increased risk of cognitive impairment in COPD patients. The promising roles of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) in improving cognitive deficits in COPD patients are also discussed. Interestingly, ω-3 PUFAs can potentially enhance the cognitive impairment symptomatology associated with COPD because they can modulate inflammatory processes, activate the antioxidant defence system, and promote amyloid-beta clearance from the brain. Thus, clinical studies are crucial to assess the efficacy of ω-3 PUFAs in managing cognitive impairment in COPD patients.

Effectiveness of vitamin-B supplements on cognition in older adults: A meta-analysis.

OBJECTIVES: We aimed to investigate the efficacy of B-vitamin and folic acid supplementation in slowing down cognitive function decline among older adults. METHODS: We searched databases for trials comparing B-vitamin and folate supplementation versus placebo in older adults identified with or without impaired cognition. RESULTS: 23 articles were eligible and included in this meta-analysis. The mean difference (MD) in homocysteine levels was significant between the compared groups (MD:-4.52; 95%CI:-5.41 to 3.63, P < 0.001). However, the difference in the Mini-Mental State Examination (MMSE) was non-significant between the compared groups with or without cognitive impairment (MD:0.19; 95%CI: -0.148 to 0.531, P = 0.27), and (MD:0.04; 95%CI:-0.1 to 0.18, P = 0.59), respectively. The difference in Clinical Dementia Rating-sum of box (CDR-SOB) scores was non-significant (MD:-0.16; 95%CI:-0.49 to 0.18; P = 0.36). CONCLUSIONS: B-vitamin and folate supplementations significantly reduced homocysteine levels. However, it failed to provide significant benefits over placebo in preventing or slowing the decline in cognitive function.

Yuanzhi Powder inhibits tau pathology in SAMP8 mice: Mechanism research of a traditional Chinese formula against Alzheimer's disease.

ETHNOPHARMACOLOGICAL RELEVANCE: Yuanzhi Powder (YZP), a classical Chinese medicine formula, is good at tonifying heart-Qi and improving cognitive ability. YZP has been reported to show therapeutic effect on alleviating the symptoms of Alzheimer's disease (AD). AIM OF THE STUDY: This study was conducted to observe the effects of YZP on improving the cognitive abilities of SAMP8 mice, and explore the involved mechanisms on inhibiting the excessive accumulation of phosphorylated tau. MATERIAL AND METHODS: Thirty SAMP8 mice were randomly divided into five groups: AD group, AD + DO group, AD + YZP group, AD + LAC group and AD + LAC + YZP group. Age-matched SAMR1 mice were served as CTL group. AD + LAC group and AD + LAC + YZP group received 1 µg Lactacystin solution via intra-cerebroventricular injection. All mice (except the CTL group and AD + LAC group) were intragastrically administrated for 8 consecutive weeks. Then, the Morris Water Maze (MWM) test was conducted for evaluation of learning and memory abilities. The pathological changes of hippocampal CA1 were observed by Hematoxylin & eosin (H&E) staining. The expression of 26S proteasome in the hippocampus was measured by Western Blot (WB) and immunohistochemistry (IHC). The expressions of total tau (Tau5) and hyperphosphorylated tau (pS199, pT231 and pS396) were detected by WB. The aggregation of hyperphosphorylated tau and the binding ability of tau protein to microtubules were evaluated respectively by immunostaining and Thioflavin-S staining and double-label immunofluorescence. RESULTS: SAMP8 mice showed serious cognitive impairment in behavioral tests. However, treatment of YZP significantly ameliorated the cognitive deficits of SAMP8 mice. The H&E staining suggested that YZP could protect against neuronal loss in SAMP8 mice. The IHC and WB results showed that YZP increases 26S proteasome expression in SAMP8 mice and 26S proteasome expression was effectively inhibited by Lactacystin. Meanwhile, The WB results demonstrated that YZP can inhibit the expression of hyperphosphorylated tau (pT231, pS396 and pS199). Furthermore, the immunostaining and Thioflavin-S staining and double-label immunofluorescence results indicated that YZP attenuates the excessive aggregation of hyperphosphorylated tau and enhances the binding ability of tau to stabilize microtubules in SAMP8 mice. CONCLUSIONS: YZP could enhance cognitive performance and learning of AD, ameliorate tau pathology and significantly improve the binding ability of tau to microtubules, based potentially on inhibiting the excessive aggregation of hyperphosphorylated tau via the 26Sproteasome pathway but not necessarily the only one.

Is Citicoline Effective in Preventing and Slowing Down Dementia?-A Systematic Review and a Meta-Analysis.

BACKGROUND: Cognitive impairment is a staggering personal and societal burden; accordingly, there is a strong interest in potential strategies for its prevention and treatment. Nutritional supplements have been extensively investigated, and citicoline seems to be a promising agent; its role in clinical practice, however, has not been established. We systematically reviewed studies on the effect of citicoline on cognitive performance. METHODS: We searched the PubMed and Cochrane Library databases for articles published between 2010 and 2022. Relevant information was extracted and presented following the PRISMA recommendations. Data were pooled using the inverse-variance method with random effects models. RESULTS: We selected seven studies including patients with mild cognitive impairment, Alzheimer's disease or post-stroke dementia. All the studies showed a positive effect of citicoline on cognitive functions. Six studies could be included in the meta-analysis. Overall, citicoline improved cognitive status, with pooled standardized mean differences ranging from 0.56 (95% CI: 0.37-0.75) to 1.57 (95% CI: 0.77-2.37) in different sensitivity analyses. The overall quality of the studies was poor. DISCUSSION: Available data indicate that citicoline has positive effects on cognitive function. The general quality of the studies, however, is poor with significant risk of bias in favor of the intervention. Other: PubMed and the Cochrane Library.

Medicinal Herbs and Nutritional Supplements for Dementia Therapy: Potential Targets and Clinical Evidence.

Spices and herbs have been used for medicinal purposes for centuries. Also, in the last decades, the use of different nutritional supplements has been implemented to treat all kinds of diseases, including those that present an alteration in cognitive functioning. Dementia is a clinical syndrome in which a person's mental and cognitive capacities gradually decline. As the disease progresses, the person's autonomy diminishes. As there is not an effective treatment to prevent progressive deterioration in many of these pathologies, nutritional interventions have been, and still are, one of the most widely explored therapeutic possibilities. In this review, we have discussed a great number of potentially interesting plants, nutritional derivatives, and probiotics for the treatment of dementia around the world. Their action mechanisms generally involve neuroprotective effects via anti-inflammatory, antioxidant, anti-apoptotic, b-amyloid, and tau anti-aggregate actions; brain blood flow improvement, and effects on synaptic cholinergic and dopaminergic neurotransmission, which may optimize cognitive performance in patients with cognitive impairment. As for their efficacy in patients with cognitive impairment and/or dementias, evidence is still scarce andthe outcomes are controversial. We consider that many of these substances have promising therapeutic properties. Therefore, the scientific community has to continue with a complete research focused on both identifying possible action mechanisms and carrying out clinical trials, preferably randomized, double-blind ones, with a greater number of patients, a long-term follow-up, dose standardization, and the use of current diagnostic criteria.

Vitamin D Supplementation and Cognition in Adults: A Systematic Review of Randomized Controlled Trials.

BACKGROUND: The role of vitamin D supplementation in improving cognition and slowing the incidence of minor and major neurocognitive disorders is a matter of debate. To our knowledge, no systematic review of randomized controlled trials (RCTs) has examined this question in adults. OBJECTIVES: The purpose of this systematic review is to synthesize the evidence regarding the effects of vitamin D supplementation on cognitive performance and neurocognitive disorders in adults. METHODS: A systematic search of scientific articles in English or French was conducted. The MEDLINE (PubMed), EMBASE (Ovid, EMBASE), PsychINFO, and Cochrane Central databases were searched for records without any limit on publication date in May 2021. Inclusion criteria were (1) human participants, (2) RCT, (3) participant age ≥ 18, (4) vitamin D supplementation as the intervention, and (5) cognition (i.e., cognitive performance or cognitive status such as cognitively healthy or minor and major neurocognitive disorder) as the primary outcome. Two independent reviewers both assessed all eligible studies' full texts and the risk of bias arising from methodological issues using a standardized procedure. RESULTS: Of the 2137 abstracts identified, 61 (2.9%) met screening inclusion criteria. After full text examination, 41 records (67.2%) were excluded. As a result, 20 RCTs (32.8%) were included in the systematic review. The review yielded mixed findings and, thus, failed to find evidence supporting cognitive benefits from vitamin D supplementation or suggesting a causal association between vitamin D and cognitive function. Half of the RCTs reported mixed results, one quarter negative results, and the last quarter positive effects for vitamin D supplementation on cognitive performance. The variability in serum 25-dihydroxyvitamin D concentration thresholds, the cognitive tests employed, the supplementation doses, and the samples' characteristics (i.e., ethnicity or number of participants) may explain these mixed findings. CONCLUSION: This systematic review of RCTs does not support a role for vitamin D supplementation in enhancing cognition in adults.

Unusual Bioactive Compounds with Antioxidant Properties in Adjuvant Therapy Supporting Cognition Impairment in Age-Related Neurodegenerative Disorders.

Cognitive function decline is strictly related to age, resulting in the loss of the ability to perform daily behaviors and is a fundamental clinical neurodegeneration symptom. It has been proven that an adequate diet, comprehensive nutrition, and a healthy lifestyle may significantly inhibit neurodegenerative processes, improving cognitive functions. Therefore, intensive research has been conducted on cognitive-enhancing treatment for many years, especially with substances of natural origin. There are several intervention programs aimed at improving cognitive functions in elderly adults. Cognitive functions depend on body weight, food consumed daily, the quality of the intestinal microflora, and the supplements used. The effectiveness in the prevention of dementia is particularly high before the onset of the first symptoms. The impact of diet and nutrition on age-associated cognitive decline is becoming a growing field as a vital factor that may be easily modified, and the effects may be observed on an ongoing basis. The paper presents a review of the latest preclinical and clinical studies on the influence of natural antioxidants on cognitive functions, with particular emphasis on neurodegenerative diseases. Nevertheless, despite the promising research results in animal models, the clinical application of natural compounds will only be possible after solving a few challenges.

Recovery of post-stroke cognitive and motor deficiencies by Shuxuening injection via regulating hippocampal BDNF-mediated Neurotrophin/Trk Signaling.

A mild ischemic stroke may cause both debilitating locomotor and cognitive decline, for which the mechanism is not fully understood, and no therapies are currently available. In this study, a nonfatal stroke model was constructed in mice by a modified middle cerebral artery occlusion (MCAO) procedure, allowing an extended recovery period up to 28 days. The extended MCAO model successfully mimicked phenotypes of a recovery phase post-stroke, including locomotor motor and cognitive deficiencies, which were effectively improved after Shuxuening injection (SXNI) treatment. Tissue slices staining showed that SXNI repaired brain injury and reduced neuronal apoptosis, especially in the hippocampus CA3 region. Transcriptomics sequencing study revealed 565 differentially expressed genes (DEGs) in the ischemic brain after SXNI treatment. Integrated network pharmacological analysis identified Neurotrophin/Trk Signaling was the most relevant pathway, which involves 15 key genes. Related DEGs were further validated by RT-PCR. Western-blot analysis showed that SXNI reversed the abnormal expression of BDNF, TrkB, Mek3 and Jnk1after stroke. ELISA found that SXNI increased brain level of p-Erk and Creb. At sub-brain level, the expression of BDNF and TrkB was decreased and GFAP was increased on the hippocampal CA3 region in the post-stroke recovery phase and this abnormality was improved by SXNI. In vitro experiments also found that oxygen glucose deprivation reduced the expression of BDNF and TrkB, which was reversed by SXNI. In summary, we conclude that SXNI facilitates the recovery of cognitive and locomotor dysfunction by modulating Neurotrophin/Trk Signaling in a mouse model for the recovery phase of post-ischemic stroke.

Olive oil and oleic acid-based self nano-emulsifying formulation of omega-3-fatty acids with improved strength, stability, and therapeutics.

AIM: To develop, characterise, and optimise SNEDDS formulation to enhance organoleptics, bioavailability, physical & oxidative-stability, and extend shelf-life of pure Ω-3-fatty acids oil for use in the food fortification industry as nutraceuticals. METHODS: SNEDDS formulations were prepared using a simple stirring technique and optimised based on in-vitro characterisation. RESULTS: The optimised SNEDDS formulation (F3) had a mean diameter of 52.9 ± 0.4 nm, PDI of 0.229 ± 0.02, zeta potential of -17.3 ± 0.1 mV, cloud temperature of 92 ± 0.2 °C, self-emulsification time of 50 ± 0.2 sec, and stable under accelerated stability conditions. Intestinal permeability study on rat ileum depicted absorption of 88.5 ± 0.2% DHA at 5 h for F3 formulation in comparison to 61.5 ± 0.2% for commercial counterpart. F3 formulation exhibited better therapeutics for melamine-induced cognitive dysfunction. CONCLUSIONS: The developed Ω-3-loaded SNEDDS heralds the future for an efficacious, safer, and higher strength formulation intended as a better substitute for currently available formulations.

Nutrition-Based Approaches in Clinical Trials Targeting Cognitive Function: Highlights of the CTAD 2020.

The Clinical Trials on Alzheimer's Disease (CTAD) 2020 conference was the stage for researchers from all over the world to present their recent and ongoing research focused on potential Alzheimer's disease (AD) treatments and prevention of cognitive decline. Among a varied range of topics, nutritional aspects arose as possibilities of treatments towards the promotion of a healthy aging. Among the discussed themes, supplementation of omega-3 polyunsaturated fatty acids and multi-nutrient approaches were presented, suggesting that long-term supplementation (i.e., over 3 years) might be needed for observing positive effects on cognitive performance. Trials testing ketogenic agents and carbohydrate-restricted diet were also presented and showed promising effects on improving cognitive function of mild-cognitive impaired (MCI) and pre-diabetic individuals, respectively, in a short-term way (i.e. after 3 to 6 months). The combination of some of the nutritional approaches with physical activity interventions raises the question on whether they would individually perform in a similar way. Promising therapies involving nutrition appear to be safe and well tolerated by volunteers. Failures on achieving positive findings raise questions on whether they were driven by specific characteristics of the studied populations, insufficient doses or duration of treatment. Notwithstanding, current evidence on the applicability of nutrition-based approaches as AD treatments are encouraging but demand further research on the topic.

The Tetramethylpyrazine Analogue T-006 Alleviates Cognitive Deficits by Inhibition of Tau Expression and Phosphorylation in Transgenic Mice Modeling Alzheimer's Disease.

T-006, a small-molecule compound derived from tetramethylpyrazine (TMP), has potential for the treatment of neurological diseases. In order to investigate the effect of T-006 prophylactic treatment on an Alzheimer's disease (AD) model and identify the target of T-006, we intragastrically administered T-006 (3 mg/kg) to Alzheimer's disease (AD) transgenic mice (APP/PS1-2xTg and APP/PS1/Tau-3xTg) for 6 and 8 months, respectively. T-006 improved cognitive ability after long-term administration in two AD mouse models and targeted mitochondrial-related protein alpha-F1-ATP synthase (ATP5A). T-006 significantly reduced the expression of phosphorylated-tau, total tau, and APP while increasing the expression of synapse-associated proteins in 3xTg mice. In addition, T-006 modulated the JNK and mTOR-ULK1 pathways to reduce both p-tau and total tau levels. Our data suggested that T-006 mitigated cognitive decline primarily by reducing the p-tau and total tau levels in 3xTg mice, supporting further investigation into its development as a candidate drug for AD treatment.

Orally Administered Cinnamon Extract Attenuates Cognitive and Neuronal Deficits Following Traumatic Brain Injury.

The present paper shows how cinnamon extract (CE) consumption mitigates neuronal loss and memory impairment following traumatic brain injury (TBI), one of the world's most common neurodegenerative diseases. TBI patients suffer short- and long-term behavioral, cognitive, and emotional impairments, including difficulties in concentration, memory loss, and depression. Research shows that CE application can mitigate cognitive and behavioral impairments in animal models for Alzheimer's and Parkinson's disease, whose pathophysiology is similar to that of TBI. This study builds on prior research by showing similar results in TBI mice models. After drinking CE for a week, mice were injured using our 70-g weight drop TBI device. For 2 weeks thereafter, the mice continued drinking CE alongside standard lab nutrition. Subsequently, the mice underwent behavioral tests to assess their memory, motor activity, and anxiety. The mice brains were harvested for immunohistochemistry staining to evaluate overall neuronal survival. Our results show that CE consumption almost completely mitigates memory impairment and decreases neuronal loss after TBI. Mice that did not consume CE demonstrated impaired memory. Our results also show that CE consumption attenuated neuronal loss in the temporal cortex and the dentate gyrus. Mice that did not consume CE suffered a significant neuronal loss. There were no significant differences in anxiety levels and motor activity between all groups. These findings show a new therapeutic approach to improve cognitive function and decrease memory loss after TBI.

Vitamins in Alzheimer's Disease-Review of the Latest Reports.

Alzheimer's disease (AD) is the most common form of dementia, and the aging of the population means that the number of cases is successively increasing. The cause of the disease has not been established, but it is suggested that many factors affect it, including nutritional aspects. As part of the work, the PubMed database has been searched, beginning from 2005, for terms related to key nutritional aspects. A diet rich in antioxidant vitamins can improve the cognitive functions of patients. Thanks to an adequate intake of B vitamins, homocysteine levels are reduced, which indirectly protects against the development of the disease. A properly balanced diet, as well as the use of appropriate supplementation, can contribute to improving the clinical condition of patients with AD.

Investigations on a polyherbal formulation for treatment of cognitive impairment in a cholinergic dysfunctional rodent model.

Alzheimer's disease is a multifactorial neurodegenerative condition manifested through acute cognitive decline, amyloid plaque deposits and neurofibrillary tangles. Complete cure for this disease remains elusive as the conventional drugs address only a single molecular target while Alzheimer's disease involves a complex interplay of different sets of molecular targets and signaling networks. In this context, the possibility of employing multi-drug combinations to rescue neurons from the dysregulated metabolic changes is being actively investigated. The present work investigates a poly-herbal formulation, Brahmi Nei that has been traditionally used for anxiolytic disorders and immunomodulatory effects, for its efficiency in ameliorating cognitive decline through a combination of behavioral, biochemical, histopathological, gene and protein expression analyses. Our results reveal that the formulation shows excellent neuroregenerative properties, rescues neurons from inflammatory damage, reduces neuritic plaque deposits and improves working memory in rodent models with scopolamine-induced dementia. The microarray analysis shows that the formulation induces the expression of pro-survival pathways and positively modulates genes involved in memory consolidation, axonal growth and proliferation in a concentration-dependent manner with therapeutic concentrations restoring the normal conditions in the brain of the diseased animals. The neuritic spine morphology confirms the long-term memory potentiation through improved mushroom spine density, increased dendritic length and connectivity. Taken together, our study provides mechanistic evidence to prove that the traditional formulation can be a superior therapeutic strategy to treat cognitive decline when compared to the conventional mono-drug treatment.

5-N-ethyl Carboxamidoadenosine Stimulates Adenosine-2b Receptor-Mediated Mitogen-Activated Protein Kinase Pathway to Improve Brain Mitochondrial Function in Amyloid Beta-Induced Cognitive Deficit Mice.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder with loss in memory as one of the cardinal features. 5-N-ethyl carboxamidoadenosine (NECA), an agonist of adenosine-2b receptor, exerts neuroprotective activity against several experimental conditions. Further, NECA activates mitogen-activated protein kinase (MAPK) and also attenuates mitochondrial toxicity in mammalian tissues other than brain. Moreover, there is no report on the role of A2b/MAPK-mediated signaling pathway in Aß-induced mitochondrial toxicity in the brain of the experimental animals. Therefore, the present study evaluated the neuroprotective activity of NECA with or without MAPK inhibitor against Aß-induced cognitive deficit and mitochondrial toxicity in the experimental rodents. Further, the effect of NECA with or without MAPK inhibitor was evaluated on Aß-induced mitochondrial toxicity in the memory-sensitive mice brain regions. Intracerebroventricular (ICV) injection of Aß 1-42 was injected to healthy male mice through Hamilton syringe via polyethylene tube to induce AD-like behavioral manifestations. NECA attenuated Aß-induced cognitive impairments in the rodents. In addition, NECA ameliorated Aß-induced Aß accumulation and cholinergic dysfunction in the selected memory-sensitive mouse HIP, PFC, and AMY. Further, NECA significantly attenuated Aß-induced mitochondrial toxicity in terms of decrease in the mitochondrial function, integrity, and bioenergetics in the brain regions of these animals. However, MAPKI diminished the therapeutic effects of NECA on behavioral, biochemical, and molecular observations in AD-like animals. Therefore, it can be speculated that NECA exhibits neuroprotective activity perhaps through MAPK activation in AD-like rodents. Moreover, A2b-mediated MAPK activation could be a promising target in the management of AD.

Mori Cortex Radicis Attenuates High Fat Diet-Induced Cognitive Impairment via an IRS/Akt Signaling Pathway.

Present study was conducted to investigate ameliorating effects of Mori Cortex radicis on cognitive impair and neuronal defects in HFD-induced (High Fat Diet-Induced) obese mice. To induce obesity, C57BL/6 mice were fed an HFD for 8 weeks, and then mice were fed the HFD plus Mori Cortex radicis extract (MCR) (100 or 200 mg/kg/day) for 6 weeks. Prior to sacrifice, body weights were measured, and Y-maze test and oral glucose tolerance test were performed. Serum lipid metabolic biomarkers (TG, LDL, and HDL/total cholesterol ratio) and antioxidant enzymes (glutathione, superoxide dismutase, and catalase), malondialdehyde (MDA), and acetylcholinesterase (AChE) levels were measured in brain tissues. The expressions of proteins related to insulin signaling (p-IRS, PI3K, p-Akt, and GLUT4) and neuronal protection (p-Tau, Bcl-2, and Bax) were examined. MCR suppressed weight gain, improved serum lipid metabolic biomarker and glucose tolerance, inhibited AChE levels and MDA production, and restored antioxidant enzyme levels in brain tissue. In addition, MCR induced neuronal protective effects by inhibiting p-Tau expression and increasing Bcl-2/Bax ratio, which was attributed to insulin-induced increases in the expressions p-IRS, PI3K, p-Akt, and GLUT4. These indicate MCR may reduce HFD-induced insulin dysfunction and neuronal damage and suggest MCR be considered a functional material for the prevention of T2DM-associated neuronal disease.

Ameliorating Activity of Ishige okamurae on the Amyloid Beta-Induced Cognitive Deficits and Neurotoxicity through Regulating ERK, p38 MAPK, and JNK Signaling in Alzheimer's Disease-Like Mice Model.

SCOPE: Alzheimer's disease (AD) is associated with amyloid beta peptide (Aß25-35 ) accumulation in brains, which induces neurotoxicity and cognitive impairment. The effects of Ishige okamurae, an edible brown algae, on Aß25-35 -induced cognitive impairment and neuronal toxicity is investigated. The aim of this study is to determine the molecular mechanisms responsible for I. okamurae extracts (IOE) mediating anti-AD effects. METHODS AND RESULTS: Oral administration of IOE significantly attenuated Aß25-35 -induced cognitive deficits, as estimated by Y-maze and Morris water maze tests. IOE also attenuated the Aß25-35 -induced cellular apoptosis and expression of inducible isoforms of nitric oxide synthases (iNOS) and cyclooxygenase-2 (COX-2) in mouse brains and PC12 cells. In addition, Aß25-35 -induced phosphorylation of ERK, p38 MAPK, and JNK in mouse brains and PC12 cells is significantly abolished by administration of IOE. In PC12 cells, pretreatment of signal inhibitors (PD98059 (MEK inhibitor), SB203580 (p38 MAPK inhibitor), and SP600125 (JNK inhibitor)) recovers Aß25-35 -mediated cellular dysregulations to the same extent as does IOE pretreatment. CONCLUSION: Taken together, the data suggest that Aß25-35 -induced AD progress may be attenuated by administration of IOE through prevention of Aß25-35 -induced phosphorylation of ERK, p38 MAPK, and JNK.

Potential effect of herbal antidepressants on cognitive deficit: Pharmacological activity and possible molecular mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: Cognitive symptom is a "core" symptom of major depressive disorder (MDD) patients with clear deficit in memory, social and occupational function, and may persist during the remitting phase. Therefore, the remission of cognitive symptom has been considered as one of the main objectives in the treatment of MDD. Herbal antidepressants have been used to treat MDD, and there has been great advances in the understanding of the ability of these herbs to improve cognitive deficit linked to brain injury and various diseases including depression, Alzheimer disease, diabetes and age-related disorders. This systematic review summarizes the evidence from preclinical studies and clinical trials of herbal antidepressants with positive effects on cognitive deficit. The potential mechanisms by which herbal antidepressants prevent cognitive deficit are also reviewed. This review will facilitate further research and applications. MATERIALS AND METHODS: We conducted an open-ended, English restricted search of MEDLINE (PubMed), Web of Science and Scopus for all available articles published or online before 31 December 2019, using terms pertaining to medical herb/phytomedicine/phytochemical/Chinese medicine and depression/major depressive disorder/antidepressant and/or cognitive impairment/cognitive deficit/cognitive dysfunction. RESULTS: 7 prescriptions, more than 30 individual herbs and 50 phytochemicals from China, Japan, Korea and India with positive effects on the depressive state and cognitive deficit are reviewed herein. The evidence from preclinical studies and clinical trials proves that these herbal antidepressants exhibit positive effects on one or more aspects of cognitive defect including spatial, episodic, aversive, and short- and long-term memory. The action mode of the improvement of cognitive deficit by these herbal antidepressants is mediated mainly through two pathways. One pathway is to promote hippocampal neurogenesis through activating brain derived neurotrophic factor-tropomyosin-related kinase B signaling. The other pathway is to prevent neuronal apoptosis through the inhibition of neuro-inflammation and neuro-oxidation. CONCLUSION: These herbal antidepressants, having potential therapy for cognitive deficit, may prevent pathological processes of neurodegenerative diseases. Furthermore, these herbal medicines should provide a treasure trove, which will accelerate the development of new antidepressants that can effectively improve cognitive symptom in MDD. Studies on their molecular mechanisms may provide more potential targets and therapeutic approaches for new drug discovery.