Protective role of luteolin against cognitive dysfunction induced by chronic cerebral hypoperfusion in rats

The possible role of cerebrolysin in the management of vascular dementia: Leveraging concepts

Cerebrolysin (CBL) is a combination of neurotrophic peptides and amino acids derived from pig brains. CBL can cross the blood-brain barrier (BBB) and its biological effect is similar to the effect of endogenous neurotrophic effects. The mechanism of action of CBL is related to the induction of neurogenesis, neuroplasticity, neuroprotection, and neurotrophicity. Therefore, CBL may be effective against the development and progression of neurodegenerative diseases such as Alzheimer disease (AD) and cerebrovascular disorders such as vascular dementia (VD). Moreover, many studies highlighted that CBL is effective in the improvement of cognitive impairment in patients with neurodegenerative diseases. However, the underlying neuroprotective effects of CBL against the VD neuropathology were not fully elucidated. Thus, this review aims to discuss the possible therapeutic efficacy of CBL in the management of VD. In conclusion, CBL could be effective therapeutic strategy in preventing and treating VD by targeting neuroinflammation, BBB injury, and chronic cerebral hypoperfusion.

Amyloid-β and heart failure in Alzheimer's disease: the new vistas

Alzheimer's disease (AD) is the most common cause of dementia and represents 75% of all dementia types. AD neuropathology is due to the progressive deposition of extracellular amyloid-beta (Aβ) peptide and intracellular hyperphosphorylated tau protein. The accumulated Aβ forms amyloid plaques, while the hyperphosphorylated tau protein forms neurofibrillary tangles (NFTs). Both amyloid plaques and NFTs are hallmarks of AD neuropathology. The fundamental mechanism involved in the pathogenesis of AD is still elusive, although Aβ is the more conceivable theory. Aβ-induced neurodegeneration and associated neuroinflammation, oxidative stress, endoplasmic reticulum stress (ER), and mitochondrial dysfunction contribute to the development of cognitive impairment and dementia. Of note, Aβ is not only originated from the brain but also produced peripherally and, via the blood-brain barrier (BBB), can accumulate in the brain and result in the development of AD. It has been shown that cardiometabolic conditions such as obesity, type 2 diabetes (T2D), and heart failure (HF) are regarded as possible risk factors for the development of AD and other types of dementia, such as vascular dementia. HF-induced chronic cerebral hypoperfusion, oxidative stress, and inflammation can induce the development and progression of AD. Interestingly, AD is regarded as a systemic disease that causes systemic inflammation and oxidative stress, which in turn affects peripheral organs, including the heart. Aβ through deranged BBB can be transported into the systemic circulation from the brain and accumulated in the heart, leading to the development of HF. These findings suggest a close relationship between AD and HF. However, the exact mechanism of AD-induced HF is not fully elucidated. Therefore, this review aims to discuss the link between AD and the risk of HF regarding the potential role of Aβ in the pathogenesis of HF.

Therapeutic Expedition of Luteolin against Brain-related Disorders: An Updated Review

Brain-related disorders include neuroinflammation, neurodegenerative disorders, and demyelination, which ultimately affect the quality of life of patients. Currently, brain-related disorders represent the most challenging health problem worldwide due to complex pathogenesis and limited availability of drugs for their management. Further, the available pharmacotherapy accompanies serious side effects, therefore, much attention has been directed toward the development of alternative therapy derived from natural sources to treat such disorders. Recently, flavonoids, natural phytochemicals, have been reported as a treatment option for preventing brain aging and disorders related to this. Among these flavonoids, dietary luteolin, a flavone, is found in many plant products such as broccoli, chamomile tea, and honeysuckle bloom having several pharmacological properties including neuroprotective activities. Therefore, the objective of this paper is to compile the available literature regarding the neuroprotective potential of luteolin and its mechanism of action. Luteolin exerts notable anti-inflammatory, antioxidant, and antiapoptotic activity suggesting its therapeutic efficacy in different neurological disorders. Numerous in-vivo and in-vitro experiments have revealed that luteolin exhibits neuroprotective potential via up-regulating the ER/ERK, PI3AKT, Nrf2 pathways and down-regulating the MAPK/JAK2STAT and NFκB pathways. Taking into account of available facts regarding the neuroprotective efficacy of luteolin, the current study highlights the beneficial effects of luteolin for the prevention, management, and treatment of different neurological disorders. Thus, luteolin can be considered an alternative for the development of new pharmacophores against various brain-related disorders.

Regulatory Role of NF-κB on HDAC2 and Tau Hyperphosphorylation in Diabetic Encephalopathy and the Therapeutic Potential of Luteolin

Diabetic encephalopathy (DE) is a severe complication of the central nervous system associated with diabetes. In this study, we investigated the regulatory role of mammalian target of rapamycin (mTOR) on nuclear factor κB (NF-κB) in mice with DE, and the neuroprotective effect and therapeutic mechanisms of luteolin, a natural flavonoid compound with anti-inflammatory, antioxidant, and neuroprotective properties. The results indicated that treatment with luteolin improved the degree of cognitive impairment in mice with DE. It also decreased the levels of phosphorylated mTOR, phosphorylated NF-κB, and histone deacetylase 2 (HDAC2) and increased the expression of brain-derived neurotrophic factor and synaptic-related proteins. Furthermore, protein-protein interaction and the Gene Ontology analysis revealed that luteolin was involved in the regulatory network of HDAC2 expression through the mTOR/NF-κB signaling cascade. Our bioinformatics and molecular docking results indicated that luteolin may also directly target HDAC2, as an HDAC2 inhibitor, to alleviate DE, complementing mTOR/NF-κB signaling inhibition. Analysis of luteolin's target proteins and their interactions suggest an effect on HDAC2 and cognition. In conclusion, HDAC2 and tau hyperphosphorylation are regulated by the mTOR/NF-κB signaling cascade in DE, and luteolin is found to reverse these effects, demonstrating its protective role in DE.

ARTICLE HIGHLIGHTS

Luteolin for neurodegenerative diseases: a review

Neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, Huntington's disease, and multiple sclerosis affect millions of people around the world. In addition to age, which is a key factor contributing to the development of all neurodegenerative diseases, genetic and environmental components are also important risk factors. Current methods of treating neurodegenerative diseases are mostly symptomatic and do not eliminate the cause of the disease. Many studies focus on searching for natural substances with neuroprotective properties that could be used as an adjuvant therapy in the inhibition of the neurodegeneration process. These compounds include flavonoids, such as luteolin, showing significant anti-inflammatory, antioxidant, and neuroprotective activity. Increasing evidence suggests that luteolin may confer protection against neurodegeneration. In this review, we summarize the scientific reports from preclinical in vitro and in vivo studies regarding the beneficial effects of luteolin in neurodegenerative diseases. Luteolin was studied most extensively in various models of Alzheimer's disease but there are also several reports showing its neuroprotective effects in models of Parkinson's disease. Though very limited, studies on possible protective effects of luteolin against Huntington's disease and multiple sclerosis are also discussed here. Overall, although preclinical studies show the potential benefits of luteolin in neurodegenerative disorders, clinical evidence on its therapeutic efficacy is still deficient.

Sorghum Grain Polyphenolic Extracts Demonstrate Neuroprotective Effects Related to Alzheimer's Disease in Cellular Assays

Sorghum grain contains high levels and a diverse profile of polyphenols (PPs), which are antioxidants known to reduce oxidative stress when consumed in the diet. Oxidative stress leading to amyloid-β (Aβ) aggregation, neurotoxicity, and mitochondrial dysfunction is implicated in the pathogenesis of Alzheimer's disease (AD). Thus, PPs have gained attention as possible therapeutic agents for combating AD. This study aimed to (a) quantify the phenolic compounds (PP) and antioxidant capacities in extracts from six different varieties of sorghum grain and (b) investigate whether these PP extracts exhibit any protective effects on human neuroblastoma (BE(2)-M17) cells against Aβ- and tau-induced toxicity, Aβ aggregation, mitochondrial dysfunction, and reactive oxygen species (ROS) induced by Aβ and tert-butyl hydroperoxide (TBHP). PP and antioxidant capacity were quantified using chemical assays. Aβ- and tau-induced toxicity was determined using the 3-(4,5-dimenthylthiazol-2-yl)-2,5-dimethyltetrazolium bromide (MTS) assay. The thioflavin T (Th-T) assay assessed anti-Aβ aggregation. The dichlorodihydrofluorescein diacetate (DCFDA) assay determined the levels of general ROS and the MitoSOX assay determined the levels of mitochondrial superoxide. Sorghum varieties Shawaya short black-1 and IS1311C possessed the highest levels of total phenolics, total flavonoids, and antioxidant capacity, and sorghum varieties differed significantly in their profile of individual PPs. All extracts significantly increased cell viability compared to the control (minus extract). Variety QL33 (at 2000 µg sorghum flour equivalents/mL) showed the strongest protective effect with a 28% reduction in Aβ-toxicity cell death. The extracts of all sorghum varieties significantly reduced Aβ aggregation. All extracts except that from variety B923296 demonstrated a significant (p ≤ 0.05) downregulation of Aβ-induced and TBHP-induced ROS and mitochondrial superoxide relative to the control (minus extract) in a dose- and variety-dependent manner. We have demonstrated for the first time that sorghum polyphenolic extracts show promising neuroprotective effects against AD, which indicates the potential of sorghum foods to exert a similar beneficial property in the human diet. However, further analysis in other cellular models and in vivo is needed to confirm these effects.

Genetic and epigenetic targets of natural dietary compounds as anti-Alzheimer's agents

Alzheimer's disease is a progressive neurodegenerative disorder and the most common cause of dementia that principally affects older adults. Pathogenic factors, such as oxidative stress, an increase in acetylcholinesterase activity, mitochondrial dysfunction, genotoxicity, and neuroinflammation are present in this syndrome, which leads to neurodegeneration. Neurodegenerative pathologies such as Alzheimer's disease are considered late-onset diseases caused by the complex combination of genetic, epigenetic, and environmental factors. There are two main types of Alzheimer's disease, known as familial Alzheimer's disease (onset < 65 years) and late-onset or sporadic Alzheimer's disease (onset ≥ 65 years). Patients with familial Alzheimer's disease inherit the disease due to rare mutations on the amyloid precursor protein (APP), presenilin 1 and 2 (PSEN1 and PSEN2) genes in an autosomal-dominantly fashion with closely 100% penetrance. In contrast, a different picture seems to emerge for sporadic Alzheimer's disease, which exhibits numerous non-Mendelian anomalies suggesting an epigenetic component in its etiology. Importantly, the fundamental pathophysiological mechanisms driving Alzheimer's disease are interfaced with epigenetic dysregulation. However, the dynamic nature of epigenetics seems to open up new avenues and hope in regenerative neurogenesis to improve brain repair in Alzheimer's disease or following injury or stroke in humans. In recent years, there has been an increase in interest in using natural products for the treatment of neurodegenerative illnesses such as Alzheimer's disease. Through epigenetic mechanisms, such as DNA methylation, non-coding RNAs, histone modification, and chromatin conformation regulation, natural compounds appear to exert neuroprotective effects. While we do not purport to cover every in this work, we do attempt to illustrate how various phytochemical compounds regulate the epigenetic effects of a few Alzheimer's disease-related genes.

Gens PSD-95 and GSK-3β expression improved by hair follicular stem cells-conditioned medium enhances synaptic transmission and cognitive abilities in the rat model of vascular dementia

INTRODUCTION

Vascular dementia (VaD) is a common type of dementia. The aim of this study was to investigate the cellular and molecular mechanism of conditioned medium (CM) in VaD.

MATERIAL AND METHODS

The rats were divided into four groups of control (n = 9), sham-operation (n = 10), VaD with vehicle (n = 9), and VaD with CM (n = 12) that received CM on days 4, 14, and 24 after 2VO. Before sacrificing the rats, cognitive performance was assessed through the open-field (OP), passive-avoidance, and Morris-water maze. The field-potential recording was used to investigate basal synaptic transmission (BST) and long-term potentiation (LTP). Subsequently, the hippocampus was dissected, and real-time PCR was used to quantify the expression levels of β1-catenin, insulin-like growth factor-1 (IGF-1), transforming growth factor-beta (TGF-β), glycogen synthase kinase-3β (GSK-3β), postsynaptic density protein 95 (PSD-95), and NR2B genes.

RESULTS

The results indicated impaired performance in behavioral tests in 2VO rats, coupled with reductions in BST and LTP induction. The expression levels of β1-catenin, IGF-1, PSD-95, and TGF-β genes decreased, whereas NR2B and GSK-3β expression increased. Treatment with CM restores the expression of PSD-95 and GSK-3β as well as fear-memory, spatial learning, and grooming number without a positive effect on memory retrieval, time spent on the periphery and center of OP. The BST recovered upon administration of CM but, the LTP induction was still impaired.

CONCLUSION

The recovery of BST in VaD rats appears to be the most important outcome of this study which is caused by the improvement of gene expression and leads to the restoration of fear memory.

Luteolin: Nature's promising warrior against Alzheimer's and Parkinson's disease

Neurodegenerative disorders (NDs) are defined as the slow loss of a group of neurons that are particularly sensitive. Due to the intricate pathophysiological processes underlying neurodegeneration, no cure exists for these conditions despite the extensive research and advances in our knowledge of the onset and course of NDs. Hence, there is a medical need for the creation of a novel therapeutic approach for NDs. By focusing on numerous signaling pathways, some natural substances derived from medicinal herbs and foods have demonstrated potent activity in treating various NDs. In this context, flavonoids have recently attracted increased popularity and research attention because of their alleged beneficial effects on health. By acting as antioxidant substances, nutritional supplements made up of flavonoids have been found to lessen the extent of NDs like Alzheimer's disease (AD) and Parkinson's disease (PD). Luteolin is a flavone that possesses potent antioxidant and anti-inflammatory properties. As a consequence, luteolin has emerged as an option for treatment with therapeutic effects on many brain disorders. More research has focused on luteolin's diverse biological targets as well as diverse signaling pathways, implying its potential medicinal properties in several NDs. This review emphasizes the possible use of luteolin as a drug of choice for the treatment as well as the management of AD and PD. In addition, this review recommends that further research should be carried out on luteolin as a potential treatment for AD and PD alongside a focus on mechanisms and clinical studies.

Comprehensive Insights into Pathophysiology of Alzheimer's Disease: Herbal Approaches for Mitigating Neurodegeneration

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and functional impairment. Despite extensive research, the exact etiology remains elusive. This review explores the multifaceted pathophysiology of AD, focusing on key hypotheses such as the cholinergic hypothesis, hyperphosphorylated Tau Protein and Amyloid β hypothesis, oxidative stress hypothesis, and the metal ion hypothesis. Understanding these mechanisms is crucial for developing effective therapeutic strategies. Current treatment options for AD have limitations, prompting the exploration of alternative approaches, including herbal interventions. Cholinesterase inhibitors, targeting the cholinergic hypothesis, have shown modest efficacy in managing symptoms. Blocking Amyloid β (Aβ) and targeting hyperphosphorylated tau protein are under investigation, with limited success in clinical trials. Oxidative stress, implicated in AD pathology, has led to the investigation of antioxidants. Natural products, such as Punica granatum Linn, Radix Scutellariae, and Curcuma longa have demonstrated antioxidant properties, along with anti-inflammatory effects, offering potential neuroprotective benefits. Several herbal extracts, including Ginkgo biloba, Bacopa monnieri, and Withania somnifera, have shown promise in preclinical studies. Compounds like Huperzine A, Melatonin, and Bryostatin exhibit neuroprotective effects through various mechanisms, including cholinergic modulation and anti-inflammatory properties. However, the use of herbal drugs for AD management faces limitations, including standardization issues, variable bioavailability, and potential interactions with conventional medications. Additionally, the efficacy and safety of many herbal products remain to be established through rigorous clinical trials. This review also highlights promising natural products currently in clinical trials, such as Resveratrol and Homotaurine, and their potential impact on AD progression. DHA, an omega-3 fatty acid, has shown cognitive benefits, while Nicotine is being explored for its neuroprotective effects. In conclusion, a comprehensive understanding of the complex pathophysiology of AD and the exploration of herbal interventions offer a holistic approach for managing this devastating disease. Future research should address the limitations associated with herbal drugs and further evaluate the efficacy of promising natural products in clinical settings.

Role of corn silk for the treatment of Alzheimer's disease: A mechanism research based on network pharmacology combined with molecular docking and experimental validation

This study aimed to research the possible mechanism and effect of active ingredients of corn silk on Alzheimer's disease (AD) by the method of network pharmacology, molecular docking, and animal experiments. The active ingredients of Corn silk were obtained by searching the TCMSP database and the targets corresponding to the active ingredients of Corn silk were obtained through the TCMSP and SwissTargetPrediction platforms, and the AD targets were obtained in the GeneCards, OMIM, and DisgeNET databases. Cytoscape was employed for creating the "active ingredient-target" relationship network; STRING and Cytoscape for creating the protein-protein interaction (PPI) network. Besides, Meta scape was used for Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of the intersecting targets; AutoDockTools and Pymol for molecular docking and visualization of core ingredients and core targets; and animal experiments for verifying the anti-AD effect of luteolin. A total of 12 active ingredients of corn silk were screened, including 465 targets and 209 intersected targets. Moreover, GO functional analysis results showed that the anti-AD effect of corn silk was mainly reflected in phosphotransferase activity, response to hormone, membrane raft, etc.; KEGG results indicated the main pathways involving cancer, Alzheimer disease, etc.; and the molecular docking results revealed excellent binding of the core ingredients (α-tocopheryl quinone, luteolin, etc.) to the core targets. Besides, the outcomes of animal experiments exhibited that luteolin not only reduced the expression of inflammatory factors TNF-α and IL-1β in mice but also attenuated inflammation. With the help of network pharmacology and experimental validation, the material basis and mechanism of the anti-AD of corn silk have been explored in this study. Briefly speaking, luteolin from corn silk plays an anti-AD role by inhibiting inflammation.

RAGE: a potential target for Epimedium's anti-neuroinflammation role in vascular dementia-insights from network pharmacology and molecular simulation

Vascular dementia (VaD), a cognitive impairment resulting from cerebrovascular issues, could be mitigated by Epimedium. This study investigates Epimedium's efficacy in VaD management through a systematic review, network pharmacology, molecular docking, and molecular dynamic simulations (MDS). Comprehensive literature searches were conducted across various databases. Epimedium's pharmacological properties were analyzed using the TCMSP database. Integration with the Aging Atlas database enabled the identification of shared targets between Epimedium and VaD. A protein-protein interaction (PPI) network was constructed, and central targets' topological attributes were analyzed using Cytoscape 3.9.1. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted using "ClusterProfiler" R package. The interactions between Epimedium and central targets were assessed by Molecular docking and MDS. Epimedium and its 23 bioactive components counteracted oxidative stress, neuroinflammation, and neuronal damage, thereby attenuating cognitive deterioration in VaD. A total of 78 common targets were identified, with 22 being significantly related to aging. Enrichment analysis identified 1769 GO terms and 139 KEGG pathways, highlighting the AGE-RAGE signaling pathway. Molecular docking revealed that 23 bioactive components, except Linoleyl acetate, effectively interacted with top central targets (JUN, MAPK14, IL6, FOS, TNF). MDS demonstrated that flavonoids Icariin, Kaempferol, Luteolin, and Quercetin formed stable complexes with RAGE. The study identifies RAGE as a novel therapeutic target for Epimedium in the mitigation of VaD via its anti-inflammatory properties.

An overview of structure-based activity outcomes of pyran derivatives against Alzheimer's disease

Pyran is a heterocyclic group containing oxygen that possesses a variety of pharmacological effects. Pyran is also one of the most prevalent structural subunits in natural products, such as xanthones, coumarins, flavonoids, benzopyrans, etc. Additionally demonstrating the neuroprotective properties of pyrans is the fact that this heterocycle has recently attracted the attention of scientists worldwide. Alzheimer's Disease (AD) treatment and diagnosis are two of the most critical research objectives worldwide. Increased amounts of extracellular senile plaques, intracellular neurofibrillary tangles, and a progressive shutdown of cholinergic basal forebrain neuron transmission are often related with cognitive impairment. This review highlights the various pyran scaffolds of natural and synthetic origin that are effective in the treatment of AD. For better understanding synthetic compounds are categorized as different types of pyran derivatives like chromene, flavone, xanthone, xanthene, etc. The discussion encompasses both the structure-activity correlations of these compounds as well as their activity against AD. Because of the intriguing actions that were uncovered by these pyran-based scaffolds, there is no question that they are at the forefront of the search for potential medication candidates that could treat Alzheimer's disease.

Honey and Alzheimer's Disease-Current Understanding and Future Prospects

Alzheimer's disease (AD), a leading cause of dementia, has been a global concern. AD is associated with the involvement of the central nervous system that causes the characteristic impaired memory, cognitive deficits, and behavioral abnormalities. These abnormalities caused by AD is known to be attributed by extracellular aggregates of amyloid beta plaques and intracellular neurofibrillary tangles. Additionally, genetic factors such as abnormality in the expression of APOE, APP, BACE1, PSEN-1, and PSEN-2 play a role in the disease. As the current treatment aims to treat the symptoms and to slow the disease progression, there has been a continuous search for new nutraceutical agent or medicine to help prevent and cure AD pathology. In this quest, honey has emerged as a powerful nootropic agent. Numerous studies have demonstrated that the high flavonoids and phenolic acids content in honey exerts its antioxidant, anti-inflammatory, and neuroprotective properties. This review summarizes the effect of main flavonoid compounds found in honey on the physiological functioning of the central nervous system, and the effect of honey intake on memory and cognition in various animal model. This review provides a new insight on the potential of honey to prevent AD pathology, as well as to ameliorate the damage in the developed AD.

Dose-dependent manner of luteolin in the modulation of spatial memory with respect to the hippocampal level of HSP70 and HSP90 in sleep-deprived rats

Sleep deprivation (SD) induces a variety of deleterious effects on different cognitive functions such as memory. Elevated neuroinflammation, oxidative stress, and apoptosis, and decreased synaptic plasticity and antioxidant capacity are involved in the deleterious effects of SD on memory. On the other hand, luteolin (a flavonoid compound) has antioxidant, neuroprotective, and anti-inflammatory properties. Also, Heat shock protein 70 (HSP70) and Heat shock protein 90 (HSP90) can be involved in modulating memory. In this study, we aimed to assess the effects of SD and luteolin on spatial learning and memory using Morris Water Maze apparatus in rats, with respect to the level of HSP70 and HSP90 in the hippocampus. Luteolin was injected intracerebroventricular (i.c.v.) at the doses of 0.5, 1, and 2 µg/rat. The results showed that SD impaired spatial memory, while luteolin dose-dependently restored SD-induced spatial memory impairment. SD increased the expression level of HSP90 in the hippocampus, whereas luteolin dose-dependently reversed the effect of SD. Furthermore, SD decreased the expression level of HSP70 protein in the hippocampus, while luteolin dose-dependently reversed the effect of SD. In conclusion, HSP70 and HSP90 may be involved in the deleterious effect of SD on memory, and in the improvement effect of luteolin on memory. This is a novel study reporting novel data and we suggest further detailed studies to better understand the interactions between SD, luteolin, and Heat shock proteins.

Structural fingerprinting of pleiotropic flavonoids for multifaceted Alzheimer's disease

Alzheimer's disease has emerged as one of the most challenging neurodegenerative diseases associated with dementia, loss of cognitive functioning and memory impairment. Despite enormous efforts to identify disease modifying technologies, the repertoire of currently approved drugs consists of a few symptomatic candidates that are not capable of halting disease progression. Moreover, these single mechanism drugs target only a small part of the pathological cascade and do not address most of the etiological basis of the disease. Development of therapies that are able to simultaneously tackle all the multiple interlinked causative factors such as amyloid protein aggregation, tau hyperphosphorylation, cholinergic deficit, oxidative stress, metal dyshomeostasis and neuro-inflammation has become the focus of intensive research in this domain. Flavonoids are natural phytochemicals that have demonstrated immense potential as medicinal agents due to their multiple beneficial therapeutic effects. The polypharmacological profile of flavonoids aligns well with the multifactorial pathological landscape of Alzheimer's disease, making them promising candidates to overcome the challenges of this neurodegenerative disorder. This review presents a detailed overview of the pleiotropic biology of flavonoids favourable for Alzheimer therapeutics and the structural basis for these effects. Structure activity trends for several flavonoid classes such as flavones, flavonols, flavanones, isoflavones, flavanols and anthocyanins are comprehensively analyzed in detail and presented.

A Review on Phyto-Therapeutic Approaches in Alzheimer's Disease

Neurodegenerative diseases occur due to progressive and sometimes irreversible loss of function and death of nerve cells. A great deal of effort is being made to understand the pathogenesis of neurodegenerative diseases. In particular, the prevalence of Alzheimer's disease (AD) is quite high, and only symptomatic therapy is available due to the absence of radical treatment. The aim of this review is to try to elucidate the general pathogenesis of AD, to provide information about the limit points of symptomatic treatment approaches, and to emphasize the potential neurologic effects of phytocompounds as new tools as therapeutic agents for disease prevention, retardation, and therapy. This survey also covers the notable properties of herbal compounds such as their effects on the inhibition of an enzyme called acetylcholinesterase, which has significant value in the treatment of AD. It has been proven that phytopharmaceuticals have long-term effects that could protect nervous system health, eliminate inflammatory responses, improve cognitive damage, provide anti-aging effects in the natural aging process, and alleviate dementia sequelae. Herbal-based therapeutic agents can afford many advantages and can be used as potentially as new-generation therapeutics or complementary agents with high compliance, fewer adverse effects, and lower cost in comparison to the traditional pharmaceutical agents in the fight against AD.

Plant based food bioactives: A boon or bane for neurological disorders

Neurological disorders are the foremost occurring diseases across the globe resulting in progressive dysfunction, loss of neuronal structure ultimately cell death. Therefore, attention has been drawn toward the natural resources for the search of neuroprotective agents. Plant-based food bioactives have emerged as potential neuroprotective agents for the treatment of neurodegenerative disorders. This comprehensive review primarily focuses on various plant food bioactive, mechanisms, therapeutic targets, in vitro and in vivo studies in the treatment of neurological disorders to explore whether they are boon or bane for neurological disorders. In addition, the clinical perspective of plant food bioactives in neurological disorders are also highlighted. Scientific evidences point toward the enormous therapeutic efficacy of plant food bioactives in the prevention or treatment of neurological disorders. Nevertheless, identification of food bioactive components accountable for the neuroprotective effects, mechanism, clinical trials, and consolidation of information flow are warranted. Plant food bioactives primarily act by mediating through various pathways including oxidative stress, neuroinflammation, apoptosis, excitotoxicity, specific proteins, mitochondrial dysfunction, and reversing neurodegeneration and can be used for the prevention and therapy of neurodegenerative disorders. In conclusion, the plant based food bioactives are boon for neurological disorders.

Metabolic Syndrome and Vascular-Associated Cognitive Impairment: a Focus on Preclinical Investigations

PURPOSE OF REVIEW

Metabolic syndrome is associated with an increased risk of vascular cognitive impairment or, in the more extreme, vascular dementia. Animal models are used to investigate the relationship between pathology and behaviour. This review summarizes the latest understanding of the role of the hippocampus and prefrontal cortex in vascular cognitive impairment, the influence of inflammation in this association while also commenting on some of the latest interventions proposed.

RECENT FINDINGS

Models of vascular cognitive impairment and vascular dementia, whether they develop from an infarct or non-infarct base, demonstrate increased neuroinflammation, reduced neuronal function and deficits in prefrontal and hippocampal-associated cognitive domains. Promising new research shows agents and environmental interventions that inhibit central oxidative stress and inflammation can reverse both pathology and cognitive dysfunction. While preclinical studies suggest that reversal of deficits in vascular cognitive impairment models is possible, replication in patients still needs to be demonstrated.

Neuroinflammation in Vascular Cognitive Impairment and Dementia: Current Evidence, Advances, and Prospects

Vascular cognitive impairment and dementia (VCID) is a major heterogeneous brain disease caused by multiple factors, and it is the second most common type of dementia in the world. It is caused by long-term chronic low perfusion in the whole brain or local brain area, and it eventually develops into severe cognitive dysfunction syndrome. Because of the disease’s ambiguous classification and diagnostic criteria, there is no clear treatment strategy for VCID, and the association between cerebrovascular pathology and cognitive impairment is controversial. Neuroinflammation is an immunological cascade reaction mediated by glial cells in the central nervous system where innate immunity resides. Inflammatory reactions could be triggered by various damaging events, including hypoxia, ischemia, and infection. Long-term chronic hypoperfusion-induced ischemia and hypoxia can overactivate neuroinflammation, causing apoptosis, blood–brain barrier damage and other pathological changes, triggering or aggravating the occurrence and development of VCID. In this review, we will explore the mechanisms of neuroinflammation induced by ischemia and hypoxia caused by chronic hypoperfusion and emphasize the important role of neuroinflammation in the development of VCID from the perspective of immune cells, immune mediators and immune signaling pathways, so as to provide valuable ideas for the prevention and treatment of the disease.

Medication Rules in Herbal Medicine for Mild Cognitive Impairment: A Network Pharmacology and Data Mining Study

Background

Although traditional Chinese medicine (TCM) has good efficacy in the treatment of mild cognitive impairment (MCI), especially memory improvement and safety, its substance basis and intervention mechanism are particularly complex and unknown. Therefore, based on network pharmacology and data mining, this study aims to explore the rules, active ingredients and mechanism of TCM in the treatment of MCI.

Methods

By searching the GeneCard, OMIM, DisGeNET and DrugBank databases, we obtained the critical targets associated with MCI. We matched the components and herbs corresponding to the important targets in the TCMSP platform. Using Cytoscape 3.7.2 software, we constructed a target-component-herb network and conducted a network topology analysis to obtain the core components and herbs. Molecular docking was used to preliminarily analyze and predict the binding activities and main binding combinations of the core targets and components. Based on the analysis of the properties, flavor and meridian distribution of herbs, the rules of herbal therapy for MCI were summarized.

Results

Twenty-eight critical targets were obtained after the screening. Using the TCMSP platform, 492 components were obtained. After standardization, we obtained 387 herbs. Based on the target-composition-herb network analysis, the core targets were ADRB2, ADRA1B, DPP4, ACHE and ADRA1D. According to the screening, the core ingredients were beta-sitosterol, quercetin, kaempferol, stigmasterol and luteolin. The core herbs were matched to Danshen, Yanhusuo, Gancao, Gouteng and Jiangxiang. It was found that the herbs were mainly warm in nature, pungent in taste and liver and lung in meridian. The molecular docking results showed that most core components exhibited strong binding activity to the target combination regardless of the in or out of network combination.

Conclusion

The results of this study indicate that herbs have great potential in the treatment of MCI. This study provides a reference and basis for clinical application, experimental research and new drug development of herbal therapy for MCI.

Luteolin Attenuates Cognitive Dysfunction Induced By Chronic Cerebral Hypoperfusion Through the Modulation of The PI3K/Akt Pathway in Rats

Introduction

In our study, we evaluated the beneficial effect of luteolin in the treatment of cognitive dysfunction in rat models induced by cerebral hypoperfusion by two-vessel occlusion (2-VO).

Material and Methods

Seventy-five male Sprague Dawley rats were subjected to 2-VO surgery, in all but 15 (the sham group, group I) the ligation being permanent to impair cognitive abilities. The sham group rats received saline instead of a drug; 15 2-VO rats were not injected at all (the model group, group II); 15 2-VO rats were administered luteolin at 50 mg/kg b.w. (the lut 50 group, group III); to a further 15 luteolin was given at 100 mg/kg b.w. (the lut 100 group, group IV); and the final 15 received nimodipine at 16 mg/kg b.w. as positive controls (the nimodipine group, group V). Object recognition and Morris water maze tests were performed to investigate memory ability. A Western blot test was also conducted to assess expression of phosphatidylinositol 3-kinase (PI3K), its downstream target protein kinase B (Akt), and the phosphorylated form (P-Akt) in cerebral cortex and hippocampus tissue samples.

Results

Significant variations in the discrimination index in the object recognition test, the escape latencies in the Morris water maze test, and expression levels of PI3K-p110α and PI3K-p85 were observed three months after 2-VO surgery in both lut groups, with a significant change in the nimodipine group compared to the model group. P-Akt and Akt were expressed significantly higher in both lut groups and the nimodipine group than in the model group.

Conclusion

Luteolin treatment of rats cognitively dysfunctional after experimental cerebral hypo perfusion was neuroprotective by activating the PI3K/Akt signals which inhibit neuronal death in the cerebral cortex and hippocampal region.

Protective effect of olive leaves phenolic compounds against neurodegenerative disorders: Promising alternative for Alzheimer and Parkinson diseases modulation

The main objective of this work was to review literature on compounds extracted from olive tree leaves, such as simple phenols (hydroxytyrosol) and flavonoids (Apigenin, apigenin-7-O-glucoside, luteolin.) and their diverse pharmacological activities as antioxidant, antimicrobial, anti-viral, anti-obesity, anti-inflammatory and neuroprotective properties. In addition, the study discussed the key mechanisms underlying their neuroprotective effects. This study adopted an approach of collecting data through the databases provided by ScienceDirect, SCOPUS, MEDLINE, PubMed and Google Scholar. This review revealed that there was an agreement on the great impact of olive tree leaves phenolic compounds on many metabolic syndromes as well as on the most prevalent neurodegenerative diseases such as Alzheimer and Parkinson. These findings would be of great importance for the use of olive tree leaves extracts as a food supplement and/or a source of drugs for many diseases. In addition, this review would of great help to beginning researchers in the field since it would offer them a general overview of the studies undertaken in the last two decades on the topic.

Safflower leaf ameliorates cognitive impairment through moderating excessive astrocyte activation in APP/PS1 mice

In addition to beta-amyloid (Aβ) plaques and neurofibrillary tangles, Alzheimer's disease (AD) is typically triggered or accompanied by abnormal inflammation, oxidative stress and astrocyte activation. Safflower (Carthamus tinctorius L.) leaf, featuring functional ingredients, is a commonly consumed leafy vegetable. Whether and how dietary safflower leaf powder (SLP) ameliorates cognitive function in an AD mouse model has remained minimally explored. Therefore, we orally administered SLP to APP/PS1 transgenic mice to explore the neuroprotective effects of SLP in preventing AD progression. We found that SLP markedly improved cognitive impairment in APP/PS1 mice, as indicated by the water maze test. We further demonstrated that SLP treatment ameliorated inflammation, oxidative stress and excessive astrocyte activation. Further investigation indicated that SLP decreased the Aβ burden in APP/PS1 mice by mediating excessive astrocyte activation. Our study suggests that safflower leaf is possibly a promising, cognitively beneficial food for preventing and alleviating AD-related dementia.

Potential of Sorghum Polyphenols to Prevent and Treat Alzheimer's Disease: A Review Article

Alzheimer's disease (AD) is characterized by the excessive deposition of extracellular amyloid-beta peptide (Aβ) and the build-up of intracellular neurofibrillary tangles containing hyperphosphorylated tau proteins. This leads to neuronal damage, cell death and consequently results in memory and learning impairments leading to dementia. Although the exact cause of AD is not yet clear, numerous studies indicate that oxidative stress, inflammation, and mitochondrial dysfunction significantly contribute to its onset and progression. There is no effective therapeutic approach to stop the progression of AD and its associated symptoms. Thus, early intervention, preferably, pre-clinically when the brain is not significantly affected, is a better option for effective treatment. Natural polyphenols (PP) target multiple AD-related pathways such as protecting the brain from Aβ and tau neurotoxicity, ameliorating oxidative damage and mitochondrial dysfunction. Among natural products, the cereal crop sorghum has some unique features. It is one of the major global grain crops but in the developed world, it is primarily used as feed for farm animals. A broad range of PP, including phenolic acids, flavonoids, and condensed tannins are present in sorghum grain including some classes such as proanthocyanidins that are rarely found in others plants. Pigmented varieties of sorghum have the highest polyphenolic content and antioxidant activity which potentially makes their consumption beneficial for human health through different pathways such as oxidative stress reduction and thus the prevention and treatment of neurodegenerative diseases. This review summarizes the potential of sorghum PP to beneficially affect the neuropathology of AD.

Ways to Address Perinatal Mast Cell Activation and Focal Brain Inflammation, including Response to SARS-CoV-2, in Autism Spectrum Disorder

The prevalence of autism spectrum disorder (ASD) continues to increase, but no distinct pathogenesis or effective treatment are known yet. The presence of many comorbidities further complicates matters, making a personalized approach necessary. An increasing number of reports indicate that inflammation of the brain leads to neurodegenerative changes, especially during perinatal life, "short-circuiting the electrical system" in the amygdala that is essential for our ability to feel emotions, but also regulates fear. Inflammation of the brain can result from the stimulation of mast cells-found in all tissues including the brain-by neuropeptides, stress, toxins, and viruses such as SARS-CoV-2, leading to the activation of microglia. These resident brain defenders then release even more inflammatory molecules and stop "pruning" nerve connections, disrupting neuronal connectivity, lowering the fear threshold, and derailing the expression of emotions, as seen in ASD. Many epidemiological studies have reported a strong association between ASD and atopic dermatitis (eczema), asthma, and food allergies/intolerance, all of which involve activated mast cells. Mast cells can be triggered by allergens, neuropeptides, stress, and toxins, leading to disruption of the blood-brain barrier (BBB) and activation of microglia. Moreover, many epidemiological studies have reported a strong association between stress and atopic dermatitis (eczema) during gestation, which involves activated mast cells. Both mast cells and microglia can also be activated by SARS-CoV-2 in affected mothers during pregnancy. We showed increased expression of the proinflammatory cytokine IL-18 and its receptor, but decreased expression of the anti-inflammatory cytokine IL-38 and its receptor IL-36R, only in the amygdala of deceased children with ASD. We further showed that the natural flavonoid luteolin is a potent inhibitor of the activation of both mast cells and microglia, but also blocks SARS-CoV-2 binding to its receptor angiotensin-converting enzyme 2 (ACE2). A treatment approach should be tailored to each individual patient and should address hyperactivity/stress, allergies, or food intolerance, with the introduction of natural molecules or drugs to inhibit mast cells and microglia, such as liposomal luteolin.

The Potential Role of Polyphenols in Oxidative Stress and Inflammation Induced by Gut Microbiota in Alzheimer's Disease

Gut microbiota (GM) play a role in the metabolic health, gut eubiosis, nutrition, and physiology of humans. They are also involved in the regulation of inflammation, oxidative stress, immune responses, central and peripheral neurotransmission. Aging and unhealthy dietary patterns, along with oxidative and inflammatory responses due to gut dysbiosis, can lead to the pathogenesis of neurodegenerative diseases, especially Alzheimer's disease (AD). Although the exact mechanism between AD and GM dysbiosis is still unknown, recent studies claim that secretions from the gut can enhance hallmarks of AD by disturbing the intestinal permeability and blood-brain barrier via the microbiota-gut-brain axis. Dietary polyphenols are the secondary metabolites of plants that possess anti-oxidative and anti-inflammatory properties and can ameliorate gut dysbiosis by enhancing the abundance of beneficial bacteria. Thus, modulation of gut by polyphenols can prevent and treat AD and other neurodegenerative diseases. This review summarizes the role of oxidative stress, inflammation, and GM in AD. Further, it provides an overview on the ability of polyphenols to modulate gut dysbiosis, oxidative stress, and inflammation against AD.

Cognitive Dysfunction after Heart Disease: A Manifestation of the Heart-Brain Axis

The functions of the brain and heart, which are the two main supporting organs of human life, are closely linked. Numerous studies have expounded the mechanisms of the brain-heart axis and its related clinical applications. However, the effect of heart disease on brain function, defined as the heart-brain axis, is less studied even though cognitive dysfunction after heart disease is one of its most frequently reported manifestations. Hypoperfusion caused by heart failure appears to be an important risk factor for cognitive decline. Blood perfusion, the immune response, and oxidative stress are the possible main mechanisms of cognitive dysfunction, indicating that the blood-brain barrier, glial cells, and amyloid-β may play active roles in these mechanisms. Clinicians should pay more attention to the cognitive function of patients with heart disease, especially those with heart failure. In addition, further research elucidating the associated mechanisms would help discover new therapeutic targets to intervene in the process of cognitive dysfunction after heart disease. This review discusses cognitive dysfunction in relation to heart disease and its potential mechanisms.

Luteolin cooperated with metformin hydrochloride alleviates lipid metabolism disorders and optimizes intestinal flora compositions of high-fat diet mice

Luteolin (LU) is a flavonoid compound and metformin hydrochloride (MH) is a kind of drug. Studies have shown that both LU and MH have the function of hypoglycemic effect. However, there are few reports indicating that LU cooperated with MH (LU·MH) can relieve lipid metabolism disorders and optimize intestinal flora compositions of high-fat diet mice. In this research, we investigated the effects of LU, MH and LU·MH on lipid metabolism disorders and intestinal flora composition in high-fat diet mice. The study found that compared with high-fat diet (HFD) alone, LU, MH and LU·MH could significantly reduce the lipid metabolism disorder. Furthermore, compared with LU or MH alone, the biochemical indicators of LU·MH were significantly improved and the results of the histopathological section also showed that LU·MH has stronger liver repair ability. It revealed that the potential mechanisms of the LU·MH alleviating lipid metabolism disorders were involved in the simultaneous regulation of SREBP-1c/FAS and SREBP-1c/ACC/Cpt-1. In addition, LU·MH could regulate the intestinal flora compositions. This includes significantly reducing the ratio of Firmicutes and Bacteroidetes(F/B) and at the family level, increasing the relative abundance of Lachnospiraceae, Helicobacteraceae, Marinifilaceae and Peptococcaceae to relieve lipid metabolism disorders. In conclusion, the work found that LU·MH regulates the signal pathway of SREBP-1c/FAS and SREBP-1c/ACC/Cpt-1 simultaneously and decreases the ratio of F/B, as well as increases the relative abundance of certain microbiota to alleviate the lipid metabolism disorders of HFD-fed mice.

Role of natural plant products against Alzheimer's disease

Alzheimer's disease (AD) is one of the major neurodegenerative disorder. Deposition of amyloid fibrils and tau protein are associated with various pathological symptoms. Currently limited medication is available for AD treatment. Most of the drugs are basically cholinesterase inhibitors and associated with various side effects. Natural plant products have shown potential as a therapeutic agent for the treatment of AD symptoms. Variety of secondary metabolites like flavonoids, tannins, terpenoids, alkaloids and phenols are used to reduce the progression of the disease. Plant products have less or no side effect and are easily available. The present review gives a detailed account of the potential of natural plant products against the AD symptoms.

IL-1β Antibody Protects Brain from Neuropathology of Hypoperfusion

Chronic brain hypoperfusion is the primary cause of vascular dementia and has been implicated in the development of white matter disease and lacunar infarcts. Cerebral hypoperfusion leads to a chronic state of brain inflammation with immune cell activation and production of pro-inflammatory cytokines, including IL-1β. In the present study, we induced chronic, progressive brain hypoperfusion in mice using ameroid constrictor, arterial stenosis (ACAS) surgery and tested the efficacy of an IL-1β antibody on the resulting brain damage. We observed that ACAS surgery causes a reduction in cerebral blood flow (CBF) of about 30% and grey and white matter damage in and around the hippocampus. The IL-1β antibody treatment did not significantly affect CBF but largely eliminated grey matter damage and reduced white matter damage caused by ACAS surgery. Over the course of hypoperfusion/injury, grip strength, coordination, and memory-related behavior were not significantly affected by ACAS surgery or antibody treatment. We conclude that antibody neutralization of IL-1β is protective from the brain damage caused by chronic, progressive brain hypoperfusion.

Protection against Alzheimer's disease by luteolin: Role of brain glucose regulation, anti-inflammatory activity, and the gut microbiota-liver-brain axis

Luteolin is a widely distributed flavone herbs and vegetables. It has anti-oxidant and anti-inflammatory activities and improves glucose metabolism by potentiating insulin sensitivity and improving β-cell function and mass. Alzheimer's disease (AD) is induced by the deposition of amyloid-beta (Aβ) in the hippocampus and the formation of neurotoxic Aβ plaques. The Aβ deposition is associated with increased formation of Aβ from amyloid precursor protein by up-regulation of β-secretase and β-site amyloid precursor protein-cleaving enzyme 1 (BACE1). Furthermore, Aβ accumulation is increased by brain insulin resistance. The impairment of insulin/IGF-1 signaling mainly in the hippocampus and brain insulin resistance is connected to signals originating in the liver and gut microbiota, known as the gut microbiota-liver-brain axis. This indicates that the changes in the production of short-chain fatty acids by the gut microbiota and pro-inflammatory cytokines can alter insulin resistance in the liver and brain. Luteolin is detected in the brain tissues after passing through the blood-brain barrier, where it can directly influence neuroinflammation and brain insulin resistance and modulate Aβ deposition. Luteolin (10-70 mg/kg bw for rodents) can modulate the systemic and brain insulin resistance, and it suppresses AD development directly, and it influences Aβ deposition by activation of the gut microbiota-liver-brain axis. In this review, we evaluate the potential of luteolin to mitigate two potential causes of AD, neuroinflammatory processes, and disruption of glucose metabolism in the brain. This review suggests that luteolin intake can enhance brain insulin resistance and neuroinflammation, directly and indirectly, to protect against the development of Alzheimer's-like disease, and the gut microbiota-liver-brain axis is mainly involved in the indirect pathway. However, most studies have been conducted in animal studies, and human clinical trials are needed.

Long-COVID syndrome-associated brain fog and chemofog: Luteolin to the rescue

COVID-19 leads to severe respiratory problems, but also to long-COVID syndrome associated primarily with cognitive dysfunction and fatigue. Long-COVID syndrome symptoms, especially brain fog, are similar to those experienced by patients undertaking or following chemotherapy for cancer (chemofog or chemobrain), as well in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or mast cell activation syndrome (MCAS). The pathogenesis of brain fog in these illnesses is presently unknown but may involve neuroinflammation via mast cells stimulated by pathogenic and stress stimuli to release mediators that activate microglia and lead to inflammation in the hypothalamus. These processes could be mitigated by phytosomal formulation (in olive pomace oil) of the natural flavonoid luteolin.

Neuroinflammation in Alzheimer's disease and beneficial action of luteolin

Alzheimer's disease (AD), already the world's most common form of dementia, is projected to continue increasing in prevalence over the next several decades. The current lack of understanding of the pathogenesis of AD has hampered the development of effective treatments. Historically, AD research has been predicated on the amyloid cascade hypothesis (ACH), which attributes disease progression to the build-up of amyloid protein. However, multiple clinical studies of drugs interfering with ACH have failed to show any benefit demonstrating that AD etiology is more complex than previously thought. Here we review the current literature on the emerging key role of neuroinflammation, especially activation of microglia, in AD pathogenesis. Moreover, we provide compelling evidence that certain flavonoids, especially luteolin formulated in olive pomace oil together with hydroxytyrosol, offers a reasonable prophylactic treatment approach due to its many beneficial actions.

Role of natural products for the treatment of Alzheimer's disease

Negative psychological and physiological consequences of neurodegenerative disorders represent a high social and health cost. Among the neurodegenerative disorders Alzheimer's disease (AD) is recognized as a leading neurodegenerative condition and a primary cause of dementia in the elderlys. AD is considered as neurodegenerative disorder that progressively impairs cognitive function and memory. According to current epidemiological data, about 50 milLion people worldwide are suffering from AD. The primary symptoms of AD are almost inappreciable and usually comprise forgetfulness of recent events. Numerous processes are involved in the development of AD, for example oxidative stress (OS) mainly due to mitochondrial dysfunction, intracellular the accumulation of hyperphosphorylated tau (τ) proteins in the form of neurofibrillary tangles, excessive the accumulation of extracellular plaques of beta-amyloid (Aβ), genetic and environmental factors. Running treatments only attenuate symptoms and temporarily reduce the rate of cognitive progression associated with AD. This means that most treatments focus only on controlLing symptoms, particularly in the initial stages of the disease. In the past, the first choice of treatment was based on natural ingredients. In this sense, diverse natural products (NPs) are capable to decrease the symptoms and alleviate the development of several diseases including AD attracting the attention of the scientific community and the pharmaceutical industry. Specifically, numerous NPs including flavonoids, gingerols, tannins, anthocyanins, triterpenes and alkaloids have been shown anti-inflammatory, antioxidant, anti-amyloidogenic, and anti-choLinesterase properties. This review provide a summary of the pathogenesis and the therapeutic goals of AD. It also discusses the available data on various plants and isolated natural compounds used to prevent and diminish the symptoms of AD.

Acupuncture attenuates cognitive deficits through α7nAChR mediated anti-inflammatory pathway in chronic cerebral hypoperfusion rats

AIMS

Chronic cerebral hypoperfusion (CCH) elicits inflammatory response, which contributes to the pathology of cognitive impairment. Several studies demonstrate that the alpha-7 nicotinic acetylcholine receptor (α7nAChR) can be a key component to modulate the inflammatory responses. We have reported previously that acupuncture attenuated cognitive deficits induced by CCH. In present study, whether effect of acupuncture was related to α7nAChR mediated anti-inflammatory pathway in CCH rats was further explored.

MAIN METHODS

Acupuncture was performed in CCH rats induced by bilateral common carotid arteries occlusion. Neuronal injury, the activation of microglia, the release of inflammatory cytokines, the expression of α7nAChR, and the activation of JAK2/STAT3 signaling pathways were detected. Cognitive function and central inflammation were evaluated after the intraperitoneal injection of an α7nAChR agonist PNU282987, or intracerebroventricular injection of an α7nAChR antagonist α-bungarotoxin (α-BGT).

KEY FINDINGS

We found that there were neuronal damage and inflammation, accompanied with the decreased expressions of α7nAChR in the hippocampus under CCH condition. Acupuncture inhibited neuronal damage, activation of microglia, and inflammatory cytokines. The expressions of α7nAChR, together with its downstream JAK2/STAT3 pathways were up regulated by acupuncture. PNU282987 mimicked the anti-inflammatory and neuroprotective effects as well as the cognitive improvements of acupuncture. Meanwhile, the benefit effects of acupuncture above were blocked by α-BGT.

SIGNIFICANCE

It was demonstrated that acupuncture promoted cognitive function and afforded neuroprotective effects against inflammation via activation of α7nAChR and its downstream JAK2-STAT3 pathway in CCH rats. It provides a new insight for acupuncture as an anti-inflammatory intervention for cognitive impairment.

Isolation and characterization of components responsible for neuroprotective effects of Allium cepa outer scale extract against ischemia reperfusion induced cerebral injury in mice

The antioxidant-mediated neuroprotective effect of Allium cepa outer scale extract (ACE) in mice with cerebral ischemia-reperfusion (I-R) injury was demonstrated in our earlier work. The current investigation aimed at establishing the bioactive component(s) responsible for this activity. Thus ACE was fractionated into ethyl acetate (EF) and aqueous (AF) fractions. These fractions were evaluated against cerebral I-R injury in mice. I-R injury in mice was induced by bilateral common carotid artery occlusion followed by 24 hr reperfusion. Memory, sensorimotor functions, cerebral infarct size, and oxidative stress were measured to address the neuroprotective mechanism of test substances. EF showed marked improvement of memory and sensorimotor functions by reducing brain oxidative stress and infarct size in mice after I-R injury. The bioactive EF was subjected to chromatographic (HPLC-PDA, HPLC-MS, preparative HPLC) and spectroscopic studies to isolate and identify the neuroprotective compounds. This lead to separation of three components, namely quercetin, quercetin 4'-O-glucoside, and the remaining fraction, from EF. The separated components were biologically evaluated. These components showed improvement in mice with I-R injury. But, EF displayed more marked neuroprotective effects as compared to the isolated components. The distinct neuroprotective outcome of EF may be credited to the synergistic action of compounds present in EF. Further studies such as evaluation of neurotoxic effects and other possible neuroprotective mechanisms are required to develop EF as a neuroprotective drug.

Bioavailability and Pharmaco-therapeutic Potential of Luteolin in Overcoming Alzheimer's Disease

Luteolin is a naturally occurring, yellow crystalline flavonoid found in numerous dietary supplements we frequently have in our meals. Studies in the last 2 decades have revealed its therapeutic potential to reduce the Alzheimer's disease (AD) symptoms in various in vitro and in vivo models. The anti-Alzheimer's potential of luteolin is attributed to its ability to suppress Aβ as well as tau aggregation or promote their disaggregation, down-regulate the expression of COX-2, NOS, MMP-9, TNF-α, interleukins and chemokines, reduce oxidative stress by scavenging ROS, modulate the activities of transcription factors CREB, cJun, Nrf-1, NF-κB, p38, p53, AP-1 and β-catenine and inhibiting the activities of various protein kinases. In several systems, luteolin has been described as a potent antioxidant and anti-inflammatory agent. In addition, we have also discussed about the bio-availability of the luteolin in the plasma. After being metabolized luteolin persists in plasma as glucuronides and sulphate-conjugates. Human clinical trials indicated no dose limiting toxicity when administered at a dose of 100 mg/day. Improvements in the formulations and drug delivery systems may further enhance the bioavailability and potency of luteolin. The current review describes in detail the data supporting these studies.

Luteolin Protects Against CIRI, Potentially via Regulation of the SIRT3/AMPK/mTOR Signaling Pathway

Mitochondrial abnormalities accelerate the progression of ischemic brain damage. Sirtuin 3 (SIRT3) is mainly found in mitochondria and affects almost all major aspects of mitochondrial function. Luteolin, a flavonoid with diverse biological properties, including antioxidant activity, inhibition of cell apoptosis and regulation of autophagy. It also modulates the activity of AMP activated kinase and/or sirtuin 1 (SIRT 1) by regulating the expression of sirtuins. We investigated the protective effects of luteolin on cerebral ischemia-reperfusion. It was found through experiments that luteolin reduced the infarcted area of MCAO rat model, and based on the experimental results, it was inferred that luteolin affected the AMPK, mTOR and SIRT3 pathways, thereby protecting brain cells. As expected, we found that luteolin can reduce the neurological function score, the degree of cerebral edema, the cerebral infarction volume, alleviate morphological changes in the cortex and hippocampus, increase neuron survival and decrease the number of apoptotic neurons. At the same time, luteolin significantly reduced the number of GFAP and Iba-1 positive glial cells in the hippocampus while enhanced the scavenging of oxygen free radicals and the activity of SOD in mitochondria. Addtionally, it can also enhance antioxidant capacity via the reversal of mitochondrial swelling and the mitochondrial transmembrane potential. Moreover, luteolin can increase SIRT3-targeted expression in mitochondria, decrease the phosphorylation of AMPK, and increase phosphor-mTOR (p-mTOR) levels, which may have occurred specifically through activation of the SIRT3/AMPK/mTOR pathway. We speculate that luteolin reduces the pathological progression of CIRI by increasing SIRT3 expression and enhancing mitochondrial function. Therefore, the results indicate that luteolin can increase the transduction of SIRT3, providing a potential mechanism for neuroprotective effects in patients with cerebral ischemia.

Embelin Improves the Spatial Memory and Hippocampal Long-Term Potentiation in a Rat Model of Chronic Cerebral Hypoperfusion

Alzheimer's disease (AD) is the second most occurring neurological disorder after stroke and is associated with cerebral hypoperfusion, possibly contributing to cognitive impairment. In the present study, neuroprotective and anti-AD effects of embelin were evaluated in chronic cerebral hypoperfusion (CCH) rat model using permanent bilateral common carotid artery occlusion (BCCAO) method. Rats were administered with embelin at doses of 0.3, 0.6 or 1.2 mg/kg (i.p) on day 14 post-surgery and tested in Morris water maze (MWM) followed by electrophysiological recordings to access cognitive abilities and synaptic plasticity. The hippocampal brain regions were extracted for gene expression and neurotransmitters analysis. Treatment with embelin at the doses of 0.3 and 0.6 mg/kg significantly reversed the spatial memory impairment induced by CCH in rats. Embelin treatment has significantly protected synaptic plasticity impairment as assessed by hippocampal long-term potentiation (LTP) test. The mechanism of this study demonstrated that embelin treatment alleviated the decreased expression of BDNF, CREB1, APP, Mapt, SOD1 and NFκB mRNA levels caused by CCH rats. Furthermore, treatment with embelin demonstrated neuromodulatory activity by its ability to restore hippocampal neurotransmitters. Overall these data suggest that embelin improve memory and synaptic plasticity impairment in CCH rats and can be a potential drug candidate for neurodegenerative disease-related cognitive disorders.

Legumain acts on neuroinflammatory to affect CUS-induced cognitive impairment

Cognitive impairment has been widely recognized as a central feature of depression. Legumain, a lysosomal cysteine protease, plays an important role in cancer, atherosclerosis, inflammation and other pathological conditions. Meanwhile, it has been reported that the activation of legumain aggravates the cognitive impairment in neurodegenerative diseases. In this study, we explored the role of legumain in cognitive impairment of stressed mice. Legumain knockout (legumain KO) and wildtype (WT) mice were divided into four groups: control group, chronic mild unpredictable stressed (CUS) group, legumain KO group and legumain KO + CUS group. Our results demonstrated that CUS (4 weeks) induced cognitive impairment in mice effectively based on Morris water maze (MWM) test and novel object recognition (NOR) test and decreased the synaptic plasticity. Additionally, CUS exposure significantly decreased the expression of hippocampal synapse related proteins and the cell density in the DG region, accompanied by increasing the expression of hippocampal inflammatory cytokines and promoting the activation of microglia in the hippocampus. Legumain KO distinctly restored the CUS-induced negative effects on the indicators mentioned above. In conclusion, our results suggested that legumain may be an effective therapeutic target for cognitive impairment as was seen within the CUS model and legumain KO reduced the level of neuroinflammation, thereby improving the hippocampal synaptic plasticity and cognitive impairment of stressed mice.

Lavandula angustifolia biological characteristics: An in vitro study

OBJECTIVE

Lavender is an aromatic shrub belonging to the Lamiaceae family. The flowers and leaves in different forms of extracts are used as herbal medicine. The accumulation of amyloid beta (Aβ) plaques, reduction of acetylcholine due to hyperactivity of acetylcholinesterase, and glutamate neurotoxicity are known to be involved in decreased level of cognitive function. In our previous study, we proved that the aqueous extract of lavender improves learning and memory. This in vitro study was designed to evaluate antiaggregative, antioxidant, and antiacetylcholinesterase activities of the herbal medicine.

METHODS

Thin layer chromatography, high-performance liquid chromatography, thioflavin, atomic force microscope (AFM), Elleman,and 2,2-diphenyl-1-picryl hydrazyl techniques were used for qualitative analysis, quantitative analysis, antiaggregative characteristics, anti-acetylcholinestrase activity and antioxidant activity of the lavender extract, respectively.

RESULTS

We found chromatographic peaks of caffeic acid and luteolin-7-glycosid in the lavender extract. Our results indicated that aqueous extract of lavender dose-dependently inhibits the formation of Aβ aggregate. The AFM technique showed that lavender largely diminished the Aβ fibril formation. We also observed a considerable radical scavenging activity of the extract.

CONCLUSIONS

Prevention of Aβ plaque formation and antioxidant activity along with nontoxic features of the lavender extract promise possible effectiveness of this plant on improving some neurological disorders including Alzheimer's disease.

Pathophysiological Role of TRPM2 in Age-Related Cognitive Impairment in Mice

Aging causes various functional changes, including cognitive impairment and inflammatory responses in the brain. Transient receptor potential melastatin 2 (TRPM2), a Ca²⁺-permeable channel expressed abundantly in immune cells, exacerbates inflammatory responses. Previously, we reported that TRPM2 on resident microglia plays a critical role in exacerbating inflammation, white matter injury, and cognitive impairment during chronic cerebral hypoperfusion; however, the physiological or pathophysiological role of TRPM2 during age-associated inflammatory responses remains unclear. Therefore, we examined the effects of TRPM2 deletion in young (2-3 months) and older (12-24 months) mice. Compared with young wild-type (WT) mice, middle-aged (12-16 months) WT mice showed working and cognitive memory dysfunction and aged (20-24 months) WT mice exhibited impaired spatial memory. However, these characteristics were not seen in TRPM2 knockout (TRPM2-KO) mice. Consistent with the finding of cognitive impairment, aged WT mice exhibited white matter injury and hippocampal damage and an increase in the number of Iba1-positive cells and amounts of pro-inflammatory cytokines in the brain; these characteristics were not seen in TRPM2-KO mice. These findings suggest that TRPM2 plays a critical role in exacerbating inflammatory responses and cognitive dysfunction during aging.

Antioxidant Effect of Flavonoids Present in Euterpe oleracea Martius and Neurodegenerative Diseases: A Literature Review

INTRODUCTION

Neurodegenerative diseases (NDDs) are progressive, directly affecting the central nervous system (CNS), the most common and recurrent are Alzheimer's disease (AD) and Parkinson's disease (PD). One factor frequently mentioned in the etiology of NDDs is the generation of free radicals and oxidative stress, producing cellular damages. Studies have shown that the consumption of foods rich in polyphenols, especially those of the flavonoid class, has been related to the low risk in the development of several diseases. Due to the antioxidant properties present in the food, a fruit that has been gaining prominence among these foods is the Euterpe oleracea Mart. (açaí), because it presents in its composition significant amounts of a subclass of the flavonoids, the anthocyanins.

METHODS

In the case review, the authors receive a basic background on the most common NDDs, oxidative stress and antioxidants. In addition, revisiting the various studies related to NDDs, including flavonoids and consumption of açaí.

RESULTS

Detailed analysis of the recently reported case studies reveal that dietary consumption of flavonoid-rich foods, such as açaí fruits, suggests the efficacy to attenuate neurodegeneration and prevent or reverse the age-dependent deterioration of cognitive function.

CONCLUSION

This systematic review points out that flavonoids presenting in açaí have the potential for the treatment of diseases such as PD and AD and are candidates for drugs in future clinical research. However, there is a need for in vitro and in vivo studies with polyphenol that prove and ratify the therapeutic potential of this fruit for several NDDs.