Ameliorating effect of luteolin on memory impairment in an Alzheimer's disease model

LC-qTOF-MS/MS phytochemical profiling of Tabebuia impetiginosa (Mart. Ex DC.) Standl. leaf and assessment of its neuroprotective potential in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Tabebuia impetiginosa (Bignoniaceae) was traditionally used for memory enhancement and central nervous system (CNS) stimulation.

AIM OF THE STUDY

This study aims to create a metabolic profile of the ethyl acetate fraction of T. impetiginosa (TEF) and investigate for the first time its neuroprotective potential on cyclophosphamide (CP)-induced chemobrain, validating its traditional use.

MATERIALS AND METHODS

Metabolite profiling of TEF was performed using Liquid Chromatography coupled with Quadrupole Time of Flight-Mass/Mass Spectrometry (LC-qTOF-MS/MS). For the in vivo study, CP (200 mg/kg, i.p.) was administered to induce cognitive impairment in rats; TEF (30 mg/kg, p.o.) was administered throughout the 14 days of the experiment to assess its role in mitigating CP-induced neuronal deficits. Behavioral tests including locomotor, Y-maze, and passive avoidance tests were conducted. Additionally, biochemical markers such as reduced glutathione (GSH), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), and caspase-3 immunoexpression were assessed in the hippocampus area.

RESULTS

Forty-four phytoconstituents were tentatively identified in TEF, mainly iridoids and organic acids. TEF showed significant memory enhancement as evidenced by the increase in step-through latency in the passive avoidance test by 1.5 folds and the increase in sequence alternation percentage (SAP) in the Y-maze test by 67.3%, as compared to CP-group. Moreover, it showed pronounced antioxidant and anti-inflammatory potentials evidenced by the significant elevation in reduced glutathione (GSH) levels by 80% and a pronounced decline in MDA and TNF-α levels by 24% and 45%, respectively relative to the CP group. TEF treatment restored normal hippocampal histological features and attenuated apoptotic caspase-3 expression by 70% compared to the CP group.

CONCLUSIONS

TEF can act as a promising natural scaffold in managing the chemobrain induced by CP in cancer patients.

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.

Flavonoids as Potential Therapeutics Against Neurodegenerative Disorders: Unlocking the Prospects

Neurodegeneration, the decline of nerve cells in the brain, is a common feature of neurodegenerative disorders (NDDs). Oxidative stress, a key factor in NDDs such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease can lead to neuronal cell death, mitochondria impairment, excitotoxicity, and Ca2+ stress. Environmental factors compromising stress response lead to cell damage, necessitating novel therapeutics for preventing or treating brain disorders in older individuals and an aging population. Synthetic medications offer symptomatic benefits but can have adverse effects. This research explores the potential of flavonoids derived from plants in treating NDDs. Flavonoids compounds, have been studied for their potential to enter the brain and treat NDDs. These compounds have diverse biological effects and are currently being explored for their potential in the treatment of central nervous system disorders. Flavonoids have various beneficial effects, including antiviral, anti-allergic, antiplatelet, anti-inflammatory, anti-tumor, anti-apoptotic, and antioxidant properties. Their potential to alleviate symptoms of NDDs is significant.

S-nitrosoglutathione modulates HDAC2 and BDNF levels in the brain and improves cognitive deficits in experimental model of Alzheimer's disease in rats

AIM

Alzheimer's disease (AD) is a neurodegenerative disorder which is characterized by cognitive deficits and abnormal memory formation. Histone acetylation is essential for hippocampal memory formation and improving the cognitive deficits, and histone deacetylase 2 (HDAC2) is increased in the hippocampus of AD patients. The present study evaluated the effects of the nitric oxide (NO) mimetics, L-arginine and the nitrosothiol NO donor, s-nitrosoglutathione (GSNO), on memory and brain HDAC2 levels in experimental animal model of sporadic Alzheimer's disease (sAD).

METHODS

AD was induced experimentally in rats by intracerebroventricular injection of streptozotocin (STZ, 3mg/kg). The effects of NO mimetics, GSNO and L-arginine, were assessed on STZ induced cognitive deficits in the Morris water maze (MWM) test, and, following this, the hippocampal homogenates were assayed for amyloid-β, brain derived neurotropic factor (BDNF) and HDAC2 levels. The neurobehavioral and biochemical data of the drug treated groups were compared with those of experimental control group.

RESULTS

The results showed that icv-STZ induced cognitive deficits were differentially attenuated by GSNO (50µg/kg) and, to a lesser extent, L-arginine (100mg/kg) with improvement in the spatial learning tasks in MWM test. These behavioral changes were associated with decreased levels of biochemical markers viz. amyloid β, BDNF and HDAC2 levels in hippocampus.

CONCLUSIONS

It is inferred that NO donors like GSNO could influence AD pathophysiology via epigenetic modification of HDAC2 inhibition.

Effectiveness of Flavonoid-Rich Diet in Alleviating Symptoms of Neurodegenerative Diseases

Over the past decades, there has been a significant increase in the burden of neurological diseases, including neurodegenerative disorders, on a global scale. This is linked to a widespread demographic trend in which developed societies are aging, leading to an increased proportion of elderly individuals and, concurrently, an increase in the number of those afflicted, posing one of the main public health challenges for the coming decades. The complex pathomechanisms of neurodegenerative diseases and resulting varied symptoms, which differ depending on the disease, environment, and lifestyle of the patients, make searching for therapies for this group of disorders a formidable challenge. Currently, most neurodegenerative diseases are considered incurable. An important aspect in the fight against and prevention of neurodegenerative diseases may be broadly understood lifestyle choices, and more specifically, what we will focus on in this review, a diet. One proposal that may help in the fight against the spread of neurodegenerative diseases is a diet rich in flavonoids. Flavonoids are compounds widely found in products considered healthy, such as fruits, vegetables, and herbs. Many studies indicated not only the neuroprotective effects of these compounds but also their ability to reverse changes occurring during the progression of diseases such as Alzheimer's, Parkinson's and amyotrophic lateral sclerosis. Here, we present the main groups of flavonoids, discussing their characteristics and mechanisms of action. The most widely described mechanisms point to neuroprotective functions due to strong antioxidant and anti-inflammatory effects, accompanied with their ability to penetrate the blood-brain barrier, as well as the ability to inhibit the formation of protein aggregates. The latter feature, together with promoting removal of the aggregates is especially important in neurodegenerative diseases. We discuss a therapeutic potential of selected flavonoids in the fight against neurodegenerative diseases, based on in vitro studies, and their impact when included in the diet of animals (laboratory research) and humans (population studies). Thus, this review summarizes flavonoids' actions and impacts on neurodegenerative diseases. Therapeutic use of these compounds in the future is potentially possible but depends on overcoming key challenges such as low bioavailability, determining the therapeutic dose, and defining what a flavonoid-rich diet is and determining its potential negative effects. This review also suggests further research directions to address these challenges.

Restoring Synaptic Function: How Intranasal Delivery of 3D-Cultured hUSSC Exosomes Improve Learning and Memory Deficits in Alzheimer's Disease

Memory problems are often the first signs of cognitive impairment related to Alzheimer's disease (AD), and stem cells and stem cell-derived exosomes (EXOs) have been studied for their therapeutic potential to improve the disease signs. While many studies have shown the anti-inflammatory and immunomodulatory effects of stem cells and exosomes on improving memory in different AD models, there is still insufficient data to determine how they modulate neural plasticity to enhance spatial memory and learning ability. Therefore, we conducted a study to investigate the effects of exosomes derived from 3D-cultured human Unrestricted Somatic Stem Cells (hUSSCs) on spatial memory and neuroplasticity markers in a sporadic rat model of AD. Using male Wistar rats induced by intracerebral ventricle injection of streptozotocin, we demonstrated that intranasal administration of hUSSC-derived exosomes could decrease Aβ accumulation and improve learning and memory in the Morris water maze test. We also observed an increase in the expression of pre-synaptic and post-synaptic molecules involved in neuronal plasticity, including NMDAR1, integrin β1, synaptophysin, pPKCα, and GAP-43, in the hippocampus. Our findings suggest that intranasal administration of exosomes can ameliorate spatial learning and memory deficits in rats, at least in part, by increasing the expression of neuroplasticity proteins. These results may encourage researchers to further investigate the molecular pathways involved in memory improvement after stem cell and exosome therapy, with the goal of increasing the efficacy and safety of exosome-based treatments for AD.

S-Nitrosoglutathione Attenuates Oxidative Stress and Improves Retention Memory Dysfunctions in Intra-Cerebroventricular-Streptozotocin Rat Model of Sporadic Alzheimer's Disease via Activation of BDNF and Nuclear Factor Erythroid 2-Related Factor-2 Antioxidant Signaling Pathway

INTRODUCTION

The brain-derived neurotrophic factor (BDNF) and transcription nuclear factor erythroid 2-related factor-2 (NRF-2) play an important role in Alzheimer's disease (AD). However, the interactive involvement of BDNF and NRF-2 in respect to antioxidant mechanisms in different parts of the AD brain is still unclear. Considering the above condition, used S-nitrosoglutathione (GSNO) to examine whether it modulates the BDNF and NRF-2 levels to activate signaling pathway to promote antioxidant levels in AD brains.

METHOD

AD was induced by intracerebroventricular infusion of streptozotocin (ICV-STZ, 3 mg/kg) in Wistar rats. The effect of GSNO was analyzed by evaluating the retention of memory in months 1, 2, and 3. After the behavior study, rats were sacrificed and accessed the amyloid beta (Aβ)-40, Aβ42, glutathione (GSH), BDNF, and NRF-2 levels in the hippocampus, cortex, and amygdala tissue.

RESULTS

Pretreatment with GSNO (50 µg/kg/intraperitoneal/day) restored the BDNF, and NRF-2 levels toward normalcy as compared with ICV-STZ + saline-treated animals. Also, GSNO treatment reversed the oxidative stress and increased the GSH levels toward normal levels. Further, reduced Aβ levels and neuronal loss in different brain regions. As a result, GSNO treatment improved the cognitive deficits in ICV-STZ-treated rats.

CONCLUSION

The results showed that endogenous nitric oxide donor GSNO improved the cognitive deficits and ICV-STZ-induced AD pathological conditions, possibly via attenuating the oxidative stress. Hence, the above finding supported that GSNO treatment may activate BDNF and NRF-2 antioxidant signaling pathways in the AD brain to normalize oxidative stress, which is the main causative factor for ICV-STZ-induced AD pathogenesis.

Polyphenols Targeting MAP Kinase Signaling Pathway in Neurological Diseases: Understanding Molecular Mechanisms and Therapeutic Targets

Polyphenols are a class of secondary metabolic products found in plants that have been extensively studied for how well they regulate biological processes, such as the proliferation of cells, autophagy, and apoptosis. The mitogen-activated protein kinase (MAPK)-mediated signaling cascade is currently identified as a crucial pro-inflammatory pathway that plays a significant role in the development of neuroinflammation. This process has been shown to contribute to the pathogenesis of several neurological conditions, such as Alzheimer's disease (AD), Parkinson's disease (PD), CNS damage, and cerebral ischemia. Getting enough polyphenols through eating habits has resulted in mitigating the effects of oxidative stress (OS) and lowering the susceptibility to associated neurodegenerative disorders, including but not limited to multiple sclerosis (MS), AD, stroke, and PD. Polyphenols possess significant promise in dealing with the root cause of neurological conditions by modulating multiple therapeutic targets simultaneously, thereby attenuating their complicated physiology. Several polyphenolic substances have demonstrated beneficial results in various studies and are presently undergoing clinical investigation to treat neurological diseases (NDs). The objective of this review is to provide a comprehensive summary of the different aspects of the MAPK pathway involved in neurological conditions, along with an appraisal of the progress made in using polyphenols to regulate the MAPK signaling system to facilitate the management of NDs.

Development of dietary small molecules as multi-targeting treatment strategies for Alzheimer's disease

Cognitive dysfunction can occur both in normal aging and age-related neurological disorders, such as mild cognitive impairment and Alzheimer's disease (AD). These disorders have few treatment options due to side effects and limited efficacy. New approaches to slow cognitive decline are urgently needed. Dietary interventions (nutraceuticals) have received considerable attention because they exhibit strong neuroprotective properties and may help prevent or minimize AD symptoms. Biological aging is driven by a series of interrelated mechanisms, including oxidative stress, neuroinflammation, neuronal apoptosis, and autophagy, which function through various signaling pathways. Recent clinical and preclinical studies have shown that dietary small molecules derived from natural sources, including flavonoids, carotenoids, and polyphenolic acids, can modulate oxidative damage, cognitive impairments, mitochondrial dysfunction, neuroinflammation, neuronal apoptosis, autophagy dysregulation, and gut microbiota dysbiosis. This paper reviews research on different dietary small molecules and their bioactive constituents in the treatment of AD. Additionally, the chemical structure, effective dose, and specific molecular mechanisms of action are comprehensively explored. This paper also discusses the advantages of using nanotechnology-based drug delivery, which significantly enhances oral bioavailability, safety, and therapeutic effect, and lowers the risk of adverse effects. These agents have considerable potential as novel and safe therapeutic agents that can prevent and combat age-related AD.

Review on anti-alzheimer drug development: approaches, challenges and perspectives

Alzheimer is an irreversible progressive neurodegenerative disease that causes failure of cerebral neurons and disability of the affected person to practice normal daily life activities. There is no concrete evidence to identify the exact reason behind the disease, so several relevant hypotheses emerged, highlighting many possible therapeutic targets, such as acetylcholinesterase, cholinergic receptors, N-methyl d-aspartate receptors, phosphodiesterase, amyloid β protein, protein phosphatase 2A, glycogen synthase kinase-3 beta, β-secretase, γ-secretase, α-secretase, serotonergic receptors, glutaminyl cyclase, tumor necrosis factor-α, γ-aminobutyric acid receptors, and mitochondria. All of these targets have been involved in the design of new potential drugs. An extensive number of these drugs have been studied in clinical trials. However, only galantamine, donepezil, and rivastigmine (ChEIs), memantine (NMDA antagonist), and aducanumab and lecanemab (selective anti-Aβ monoclonal antibodies) have been approved for AD treatment. Many drugs failed in the clinical trials to such an extent that questions have been posed about the significance of some of the aforementioned targets. On the contrary, the data of other drugs were promising and shed light on the significance of their targets for the development of new potent anti-alzheimer drugs.

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.

Luteolin alleviates depression-like behavior by modulating glycerophospholipid metabolism in the hippocampus and prefrontal cortex of LOD rats

BACKGROUND

Late-onset depression (LOD) is defined as primary depression that first manifests after the age of 65. Luteolin (LUT) is a natural flavonoid that has shown promising antidepressant effects and improvement in neurological function in previous studies.

AIMS

In this study, we utilized UPLC-MS/MS non-targeted metabolomics techniques, along with molecular docking technology and experimental validation, to explore the mechanism of LUT in treating LOD from a metabolomics perspective.

RESULTS

The behavioral results of our study demonstrate that LUT significantly ameliorated anxiety and depression-like behaviors while enhancing cognitive function in LOD rats. Metabolomic analysis revealed that the effects of LUT on LOD rats were primarily mediated through the glycerophospholipid metabolic pathway in the hippocampus and prefrontal cortex. The levels of key lipid metabolites, phosphatidylserine (PS), phosphatidylcholine (PC), and phosphatidylethanolamine (PE), in the glycerophospholipid metabolic pathway were significantly altered by LUT treatment, with PC and PE showing significant correlations with behavioral indices. Molecular docking analysis indicated that LUT had strong binding activity with phosphatidylserine synthase 1 (PTDSS1), phosphatidylserine synthase 2 (PTDSS2), and phosphatidylserine decarboxylase (PISD), which are involved in the transformation and synthesis of PC, PE, and PS. Lastly, our study explored the reasons for the opposing trends of PC, PE, and PS in the hippocampus and prefrontal cortex from the perspective of autophagy, which may be attributable to the bidirectional regulation of autophagy in distinct brain regions.

CONCLUSIONS

Our results revealed significant alterations in the glycerophospholipid metabolism pathways in both the hippocampus and prefrontal cortex of LOD rats. Moreover, LUT appears to regulate autophagy disorders by specifically modulating glycerophospholipid metabolism in different brain regions of LOD rats, consequently alleviating depression-like behavior in these animals.

A Capsicum annuum L. seed extract exerts anti-neuroexcitotoxicity in HT22 hippocampal neurons

The hippocampal memory deficit stands out as a primary symptom in neurodegenerative diseases, including Alzheimer's disease. While numerous therapeutic candidates have been proposed, they primarily serve to delay disease progression. Given the irreversible brain atrophy or injury associated with these conditions, current research efforts are concentrated on preventive medicine strategies. Herein, we investigated whether the extracts of Capsicum annuum L. seeds (CSE) and Capsicum annuum L. pulp (CPE) have preventive properties against glutamate-induced neuroexcitotoxicity (one of the main causes of Alzheimer's disease) in HT22 hippocampal neuronal cells. Pretreatment with CSE demonstrated significant anti-neuroexcitotoxic activity, whereas CPE did not exhibit such effects. Specifically, CSE pretreatment dose-dependently inhibited the elevation of excitotoxic elements (intracellular calcium influx and reactive oxygen species; ROS) and apoptotic elements (p53 and cleaved caspase-3). In addition, the glutamate-induced alterations of neuronal activity indicators (brain-derived neurotrophic factor; BDNF and cAMP response element-binding protein phosphorylation; CREB) were significantly attenuated by CSE treatment. We also found that luteolin is the main bioactive compound corresponding to the anti-neuroexcitotoxic effects of CSE. Our results strongly suggest that Capsicum annuum L. seeds (but not its pulp) could be candidates for neuro-protective resources especially under conditions of neuroexcitotoxicity. Its underlying mechanisms may involve the amelioration of ROS-mediated cell death and BDNF-related neuronal inactivity and luteolin would be an active compound.

A prospective review of the health-promoting potential of Jing Si Herbal Tea

Traditional Chinese medicine (TCM) has gained considerable attention over the past few years for its multicomponent, multitarget, and multi-pathway approach to treating different diseases. Studies have shown that TCMs as adjuvant therapy along with conventional treatment may benefit in safely treating various disorders. However, investigations on finding effective herbal combinations are ongoing. A novel TCM formula, "Jing Si Herbal Tea (JSHT)," has been reported recently for their health-promoting effects in improving overall body and mental health. JSHT is a combination of eight herbs recognized in Chinese herbal pharmacopoeia for their anti-viral, anti-aging, and anti-cancer properties as well as protective effects against cardiovascular, metabolic, neural, digestive, and genitourinary diseases. Thus, to better understand the beneficial effects of the ingredients of JSHT on health, this review intends to summarize the preclinical and clinical studies of the ingredients of JSHT on human health and diseases, and possible therapeutic effects with the related mode of actions and future prospects for their application in complementary therapies.

Exploring the Potential Molecular Mechanism of the Shugan Jieyu Capsule in the Treatment of Depression through Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation

BACKGROUND

Shugan Jieyu Capsule (SJC) is a pure Chinese medicine compound prepared with Hypericum perforatum and Acanthopanacis senticosi. SJC has been approved for the clinical treatment of depression, but the mechanism of action is still unclear.

OBJECTIVES

Network pharmacology, molecular docking, and molecular dynamics simulation (MDS) were applied in the present study to explore the potential mechanism of SJC in the treatment of depression.

METHODS

TCMSP, BATMAN-TCM, and HERB databases were used, and related literature was reviewed to screen the effective active ingredients of Hypericum perforatum and Acanthopanacis senticosi. TCMSP, BATMAN-TCM, HERB, and STITCH databases were used to predict the potential targets of effective active ingredients. GeneCards database, DisGeNET database, and GEO data set were used to obtain depression targets and clarify the intersection targets of SJC and depression. STRING database and Cytoscape software were used to build a protein-protein interaction (PPI) network of intersection targets and screen the core targets. The enrichment analysis on the intersection targets was conducted. Then the receiver operator characteristic (ROC) curve was constructed to verify the core targets. The pharmacokinetic characteristics of core active ingredients were predicted by SwissADME and pkCSM. Molecular docking was performed to verify the docking activity of the core active ingredients and core targets, and molecular dynamics simulations were performed to evaluate the accuracy of the docking complex.

RESULTS

We obtained 15 active ingredients and 308 potential drug targets with quercetin, kaempferol, luteolin, and hyperforin as the core active ingredients. We obtained 3598 targets of depression and 193 intersection targets of SJC and depression. A total of 9 core targets (AKT1, TNF, IL6, IL1B, VEGFA, JUN, CASP3, MAPK3, PTGS2) were screened with Cytoscape 3.8.2 software. A total of 442 GO entries and 165 KEGG pathways (p <0.01) were obtained from the enrichment analysis of the intersection targets, mainly enriched in IL-17, TNF, and MAPK signaling pathways. The pharmacokinetic characteristics of the 4 core active ingredients indicated that they could play a role in SJC antidepressants with fewer side effects. Molecular docking showed that the 4 core active components could effectively bind to the 8 core targets (AKT1, TNF, IL6, IL1B, VEGFA, JUN, CASP3, MAPK3, PTGS2), which were related to depression by the ROC curve. MDS showed that the docking complex was stable.

CONCLUSION

SJC may treat depression by using active ingredients such as quercetin, kaempferol, luteolin, and hyperforin to regulate targets such as PTGS2 and CASP3 and signaling pathways such as IL-17, TNF, and MAPK, and participate in immune inflammation, oxidative stress, apoptosis, neurogenesis, etc.

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.

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.

Neuroprotective Agents with Therapeutic Potential for COVID-19

COVID-19 patients can exhibit a wide range of clinical manifestations affecting various organs and systems. Neurological symptoms have been reported in COVID-19 patients, both during the acute phase of the illness and in cases of long-term COVID. Moderate symptoms include ageusia, anosmia, altered mental status, and cognitive impairment, and in more severe cases can manifest as ischemic cerebrovascular disease and encephalitis. In this narrative review, we delve into the reported neurological symptoms associated with COVID-19, as well as the underlying mechanisms contributing to them. These mechanisms include direct damage to neurons, inflammation, oxidative stress, and protein misfolding. We further investigate the potential of small molecules from natural products to offer neuroprotection in models of neurodegenerative diseases. Through our analysis, we discovered that flavonoids, alkaloids, terpenoids, and other natural compounds exhibit neuroprotective effects by modulating signaling pathways known to be impacted by COVID-19. Some of these compounds also directly target SARS-CoV-2 viral replication. Therefore, molecules of natural origin show promise as potential agents to prevent or mitigate nervous system damage in COVID-19 patients. Further research and the evaluation of different stages of the disease are warranted to explore their potential benefits.

Comprehensive Review of Nutraceuticals against Cognitive Decline Associated with Alzheimer's Disease

Nowadays, nutraceuticals are being incorporated into functional foods or used as supplements with nonpharmacological approaches in the prevention and management of several illnesses, including age-related conditions and chronic neurodegenerative diseases. Nutraceuticals are apt for preventing and treating such disorders because of their nontoxic, non-habit-forming, and efficient bioactivities for promoting neurological well-being due to their ability to influence cellular processes such as neurogenesis, synaptogenesis, synaptic transmission, neuro-inflammation, oxidative stress, cell death modulation, and neuronal survival. The capacity of nutraceuticals to modify all of these processes reveals the potential to develop food-based strategies to aid brain development and enhance brain function, prevent and ameliorate neurodegeneration, and possibly reverse the cognitive impairment observed in Alzheimer's disease, the most predominant form of dementia in the elderly. The current review summarizes the experimental evidence of the neuroprotective capacity of nutraceuticals against Alzheimer's disease, describing their mechanisms of action and the in vitro and in vivo models applied to evaluate their neuroprotective potential.

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.

Anti-Inflammatory Effects of Flavonoids in Common Neurological Disorders Associated with Aging

Aging reduces homeostasis and contributes to increasing the risk of brain diseases and death. Some of the principal characteristics are chronic and low-grade inflammation, a general increase in the secretion of proinflammatory cytokines, and inflammatory markers. Aging-related diseases include focal ischemic stroke and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Flavonoids are the most common class of polyphenols and are abundantly found in plant-based foods and beverages. A small group of individual flavonoid molecules (e.g., quercetin, epigallocatechin-3-gallate, and myricetin) has been used to explore the anti-inflammatory effect in vitro studies and in animal models of focal ischemic stroke and AD and PD, and the results show that these molecules reduce the activated neuroglia and several proinflammatory cytokines, and also, inactivate inflammation and inflammasome-related transcription factors. However, the evidence from human studies has been limited. In this review article, we highlight the evidence that individual natural molecules can modulate neuroinflammation in diverse studies from in vitro to animal models to clinical studies of focal ischemic stroke and AD and PD, and we discuss future areas of research that can help researchers to develop new therapeutic agents.

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.

Aqueous extract of Ceratonia siliqua L. leaves elicits antioxidant, anti-inflammatory, and AChE inhibiting effects in amyloid-β42-induced cognitive deficit mice: Role of α7-nAChR in modulating Jak2/PI3K/Akt/GSK-3β/β-catenin cascade

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder attributed to several etiological factors including cholinergic dysregulation, neuroinflammation, oxidative stress, β-amyloidogenesis, and tauopathy. This demands the search for multitarget drugs, especially of natural sources owing to their pleiotropic activities and low adverse effects. The present study was conducted to investigate the cognitive-improving potential of Ceratonia siliqua L. (Cs) extract compared with donepezil, an acetylcholinesterase inhibitor, on AD-like pathological alterations induced by single intracerebroventricular amyloid-β42 (Aβ42) injection in mice. Aβ42-injected mice were treated with Cs (100 mg/kg/day, po) with or without methyllycaconitine (MLA; 1 mg/kg/day, ip), an α7-nAChR antagonist. Aβ42-injected animals demonstrated an elevation of hippocampal Aβ42, p-Tau, and acetylcholinesterase. They also showed a decline in phosphorylated levels of Jak2, PI3K, Akt, and GSK-3β, leading to induction of neuroinflammation and oxidative stress. Noteworthy, Cs improved the histopathological and behavioral variables in addition to mitigating AD hallmarks. It also exerted neuroprotection by reducing NF-κBp65 and TNF-α, while elevating Nrf2 and HO-1, along with stabilizing β-catenin under the impact of Jak2/PI3K/Akt/GSK-3β signaling. These beneficial effects of Cs were abrogated by MLA co-administration signifying the α7-nAChR involvement in Cs-mediated effects. Therefore, Cs can ameliorate Aβ42-induced neurodegeneration by modulating Jak2/PI3K/Akt/GSK-3β/β-catenin axis in an α7-nAChR-dependent manner.

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.

A role for flavonoids in the prevention and/or treatment of cognitive dysfunction, learning, and memory deficits: a review of preclinical and clinical studies

OBJECTIVE

Natural food substances, due to high rates of antioxidants, antiviral and anti-inflammatory properties, have been proposed to have the potential for the prevention or treatment of cognitive deficits, learning and memory deficits and neuro inflammation. In particular, medicinal plants with rich amounts of beneficial components such as flavonoids are one of the most promising therapeutic candidates for the cognitive deficit and memory loss. Herein, we aimed to review the impact of medicinal plants with focus on flavonoids on cognitive dysfunction, learning and memory loss by considering their signaling pathways.

METHODS

We extracted 93 preclinical and clinical studies related to the effects of flavonoids on learning and memory and cognition from published papers between 2000 and 2021 in the MEDLINE/PubMed, Cochrane Library, SCOPUS, and Airiti Library databases.

RESULTS

In the preclinical studies, at least there seem to be two main neurological and biological processes in which flavonoids contribute to the improvement and/or prevention of learning, memory deficit and cognitive dysfunction: (1) Regulation of neurotransmission system and (2) Enhancement of neurogenesis, synaptic plasticity and neuronal survival.

CONCLUSION

Although useful effects of flavonoids on learning and memory in preclinical investigations have been approved, more clinical trials are required to find out whether flavonoids and/or other ingredients of plants have the potent to prevent or treat neurodegenerative disorders.

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.

The protective effect of luteolin on the depression-related dry eye disorder through Sirt1/NF-κB/NLRP3 pathway

Luteolin has been reported to exhibit therapeutic effect on depressive-like behaviors in mice. Nevertheless, the therapeutic effect of luteolin on the depression-related dry eye disorder remains inconclusive. In this study, C57 mice were subjected to chronic unpredictable mild stress in a dry environment (relative humidity in the cage <40%). The behavioral test and phenol red cotton thread test were employed to select the mice with both dry eye and depression-like behavior. The mechanism of luteolin on depression-related dry eye disorder was assessed by the Sirt1 selective inhibitor EX-527. Luteolin alleviated depressive-like behaviors induced by CUMS, increased tear secretion and restored corneal defects in mice. The secretions of pro-inflammatory factors IL-1β, IL-6, IL-18 and TNF-α were decreased in hippocampi and corneal tissues by Luteolin treatment. Luteolin treatment up-regulated Sirt1 expression and down-regulated Ac-NF-κB, NLRP3, Ac-Caspase-1, GSDMD-N, Cleaved IL-1β, and Cleaved IL-18 expressions. In addition, the selective inhibition of Sirt1 could weaken the therapeutic effect of luteolin on depression-related dry eye disorder. The beneficial effect of luteolin through Sirt1/NF-κB/NLRP3 signaling pathway might be a therapeutic strategy for the depression-related dry eye disorder.

Luteolin protects DYT-PRKRA cells from apoptosis by suppressing PKR activation

DYT-PRKRA is a movement disorder caused by mutations in the PRKRA gene, which encodes for PACT, the protein activator of interferon-induced, double-stranded RNA (dsRNA)-activated protein kinase PKR. PACT brings about PKR's catalytic activation by a direct binding in response to stress signals and activated PKR phosphorylates the translation initiation factor eIF2α. Phosphorylation of eIF2α is the central regulatory event that is part of the integrated stress response (ISR), an evolutionarily conserved intracellular signaling network essential for adapting to environmental stresses to maintain healthy cells. A dysregulation of either the level or the duration of eIF2α phosphorylation in response to stress signals causes the normally pro-survival ISR to become pro-apoptotic. Our research has established that the PRKRA mutations reported to cause DYT-PRKRA lead to enhanced PACT-PKR interactions causing a dysregulation of ISR and an increased sensitivity to apoptosis. We have previously identified luteolin, a plant flavonoid, as an inhibitor of the PACT-PKR interaction using high-throughput screening of chemical libraries. Our results presented in this study indicate that luteolin is markedly effective in disrupting the pathological PACT-PKR interactions to protect DYT-PRKRA cells against apoptosis, thus suggesting a therapeutic option for using luteolin to treat DYT-PRKRA and possibly other diseases resulting from enhanced PACT-PKR interactions.

Carthamus tinctorius L.: A natural neuroprotective source for anti-Alzheimer's disease drugs

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer's disease (AD) is a multicausal neurodegenerative disease clinically characterized by generalized dementia. The pathogenic process of AD not only is progressive and complex but also involves multiple factors and mechanisms, including β-amyloid (Aβ) aggregation, tau protein hyperphosphorylation, oxidative stress, and neuroinflammation. As the first-line treatment for AD, cholinesterase inhibitors can, to a certain extent, relieve AD symptoms and delay AD progression. Nonetheless, the current treatment strategies for AD are far from meeting clinical expectations, and more options for AD treatment should be applied in clinical practice.

AIM OF THE REVIEW

The aim of this review was to investigate published reports of C. tinctorius L. and its active constituents in AD treatment through a literature review.

MATERIALS AND METHODS

Information was retrieved from scientific databases including Web of Science, ScienceDirect, Scopus, Google Scholar, Chemical Abstracts Services and books, PubMed, dissertations and technical reports. Keywords used for the search engines were "Honghua" or "Carthamus tinctorius L." or "safflower" in conjunction with "(native weeds OR alien invasive)"AND "Chinese herbal medicine".

RESULTS

A total of 47 literatures about C. tinctorius L. and its active constituents in AD treatment through signaling pathways, immune cells, and disease-related mediators and systematically elucidates potential mechanisms from the point of anti-Aβ aggregation, suppressing tau protein hyperphosphorylation, increasing cholinergic neurotransmitters levels, inhibiting oxidative stress, anti-neuroinflammation, ameliorating synaptic plasticity, and anti-apoptosis.

CONCLUSIONS

Chinese herbal medicine (CHM) is a treasure endowed by nature to mankind. Emerging studies have confirmed that CHM and its active constituents play a positive role in AD treatment. Carthamus tinctorius L., the most commonly used CHM, can be used with medicine and food, with the effect of activating blood circulation and eliminating blood stasis. In the paper, we have concluded that the existing therapeutic mechanisms of C. tinctorius L. and summarized the potential mechanisms of C. tinctorius L. and its active constituents in AD treatment through a literature review.

The Potential Neuroprotective Effect of Cyperus esculentus L. Extract in Scopolamine-Induced Cognitive Impairment in Rats: Extensive Biological and Metabolomics Approaches

The aim of the present study is to investigate the phytochemical composition of tiger nut (TN) (Cyperus esculentus L.) and its neuroprotective potential in scopolamine (Scop)-induced cognitive impairment in rats. The UHPLC-ESI-QTOF-MS analysis enabled the putative annotation of 88 metabolites, such as saccharides, amino acids, organic acids, fatty acids, phenolic compounds and flavonoids. Treatment with TN extract restored Scop-induced learning and memory impairments. In parallel, TN extract succeeded in lowering amyloid beta, β-secretase protein expression and acetylcholine esterase (AChE) activity in the hippocampus of rats. TN extract decreased malondialdehyde levels, restored antioxidant levels and reduced proinflammatory cytokines as well as the Bax/Bcl2 ratio. Histopathological analysis demonstrated marked neuroprotection in TN-treated groups. In conclusion, the present study reveals that TN extract attenuates Scop-induced memory impairments by diminishing amyloid beta aggregates, as well as its anti-inflammatory, antioxidant, anti-apoptotic and anti-AChE activities.

Effect of ivabradine on cognitive functions of rats with scopolamine-induced dementia

Alzheimer's disease is among the challenging diseases to social and healthcare systems because no treatment has been achieved yet. Although the ambiguous pathological mechanism underlying this disorder, ion channel dysfunction is one of the recently accepted possible mechanism. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels play important roles in cellular excitability and synaptic transmission. Ivabradine (Iva), an HCN blocker, is acting on HCN channels, and is clinically used for angina and arrhythmia. The current study aimed to investigate the therapeutic effects of Iva against scopolamine (Sco) induced dementia. To test our hypothesis, Sco and Iva injected rats were tested for behavioural changes, followed by ELISA and histopathological analysis of the hippocampus. Induced dementia was confirmed by behavioural tests, inflammatory cytokines and oxidative stress tests and histopathological signs of neurodegeneration, multifocal deposition of congo red stained amyloid beta plaques and the decreased optical density of HCN1 immunoreactivity. Iva ameliorated the scopolamine-induced dysfunction, the hippocampus restored its normal healthy neurons, the amyloid plaques disappeared and the optical density of HCN1 immunoreactivity increased in hippocampal cells. The results suggested that blockage of HCN1 channels might underly the Iva therapeutic effect. Therefore, Iva might have beneficial effects on neurological disorders linked to HCN channelopathies.

The Potential of Small Molecules to Modulate the Mitochondria–Endoplasmic Reticulum Interplay in Alzheimer’s Disease

Alzheimer’s disease (AD) is the most common neurodegenerative disease affecting a growing number of elderly individuals. No disease-modifying drugs have yet been identified despite over 30 years of research on the topic, showing the need for further research on this multifactorial disease. In addition to the accumulation of amyloid β-peptide (Aβ) and hyperphosphorylated tau (p-tau), several other alterations have been associated with AD such as calcium (Ca2+) signaling, glucose-, fatty acid-, cholesterol-, and phospholipid metabolism, inflammation, and mitochondrial dysfunction. Interestingly, all these processes have been associated with the mitochondria–endoplasmic reticulum (ER) contact site (MERCS) signaling hub. We and others have hypothesized that the dysregulated MERCS function may be one of the main pathogenic pathways driving AD pathology. Due to the variety of biological processes overseen at the MERCS, we believe that they constitute unique therapeutic targets to boost the neuronal function and recover neuronal homeostasis. Thus, developing molecules with the capacity to correct and/or modulate the MERCS interplay can unleash unique therapeutic opportunities for AD. The potential pharmacological intervention using MERCS modulators in different models of AD is currently under investigation. Here, we survey small molecules with the potential to modulate MERCS structures and functions and restore neuronal homeostasis in AD. We will focus on recently reported examples and provide an overview of the current challenges and future perspectives to develop MERCS modulators in the context of translational research.

Luteolin reduces fear, anxiety, and depression in rats with post-traumatic stress disorder

Exposure to severe stress can lead to the development of neuropsychiatric disorders, including post-traumatic stress disorder (PTSD). The cause of PTSD is dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis and an imbalance of monoamines. Fruits and vegetables contain large amounts of luteolin (LU; 3′,4′,5,7-tetrahydroxylflavone), which has various pharmacological activities such as anti-inflammatory, antioxidant, and anti-allergic effects. We investigated the effects of LU on fear, depression, and anxiety following monoamine imbalance and hyperactivation of the HPA axis in rats exposed to single prolonged stress (SPS). Male rats were dosed with LU (10 and 20 mg/kg) once daily for 14 days after exposure to SPS. Administration of LU reduced fear freezing responses to extinction recall and depression- and anxiety-like behaviors, and suppressed increases in plasma corticosterone and adrenocorticotropic hormone levels. Also, administration of LU restored the increased norepinephrine and decreased serotonin levels in the structures within the fear circuit, medial prefrontal cortex, and hippocampus. Our results showed that administration of LU improved freezing behavior according in a situation-dependent manner, and showed anti-depressant and anxiolytic effects. Thus, LU may be a useful therapeutic agent to prevent traumatic stress such as PTSD.

Oxidative Stress in Tauopathies: From Cause to Therapy

Oxidative stress (OS) is the result of an imbalance between the production of reactive oxygen species (ROS) and the antioxidant capacity of cells. Due to its high oxygen demand, the human brain is highly susceptible to OS and, thus, it is not a surprise that OS has emerged as an essential component of the pathophysiology of several neurodegenerative diseases, including tauopathies. Tauopathies are a heterogeneous group of age-related neurodegenerative disorders characterized by the deposition of abnormal tau protein in the affected neurons. With the worldwide population aging, the prevalence of tauopathies is increasing, but effective therapies have not yet been developed. Since OS seems to play a key role in tauopathies, it has been proposed that the use of antioxidants might be beneficial for tau-related neurodegenerative diseases. Although antioxidant therapies looked promising in preclinical studies performed in cellular and animal models, the antioxidant clinical trials performed in tauopathy patients have been disappointing. To develop effective antioxidant therapies, the molecular mechanisms underlying OS in tauopathies should be completely understood. Here, we review the link between OS and tauopathies, emphasizing the causes of OS in these diseases and the role of OS in tau pathogenesis. We also summarize the antioxidant therapies proposed as a potential treatment for tauopathies and discuss why they have not been completely translated to clinical trials. This review aims to provide an integrated perspective of the role of OS and antioxidant therapies in tauopathies. In doing so, we hope to enable a more comprehensive understanding of OS in tauopathies that will positively impact future studies.

Luteolin Phosphate Derivatives Generated by Cultivating Bacillus subtilis var. Natto BCRC 80517 with Luteolin

Luteolin (LUT), a plant-derived flavone, exhibits various bioactivities; however, the poor aqueous solubility hampers its applications. Here, we revealed bioconversion of LUT by Bacillus subtilis BCRC 80517, yielding three water-soluble phosphate conjugates. These derivatives were identified as luteolin 4'-O-phosphate (L4'P), luteolin 3'-O-phosphate (L3'P), and luteolin 7-O-phosphate (L7P) by LC-ESI-MS/MS and NMR. Besides, we found that Bacillus subtilis BCRC 80517 was able to convert different levels of LUT but showed a limited conversion rate. By observing bacterial morphology with transmission electron microscopy and confocal fluorescence microscopy, we found that LUT disrupted the bacterial membrane integrity, which explained the incomplete conversion. Additionally, we revealed a spontaneous intramolecular transesterification of L4'P to L3'P, the thermodynamically more stable form, under acidic conditions and proposed the possible mechanism involving a cyclic phosphate as the intermediate. This study provides insight into development of a potent structural modification strategy to enhance the solubility of LUT through biophosphorylation.

Effect of Yakae-Prajamduen-Jamod Traditional Thai Remedy on Cognitive Impairment in an Ovariectomized Mouse Model and Its Mechanism of Action

Cognitive impairment is a neurological symptom caused by reduced estrogen levels in menopausal women. The Thai traditional medicine, Yakae-Prajamduen-Jamod (YPJ), is a formula consisting of 23 medicinal herbs and has long been used to treat menopausal symptoms in Thailand. In the present study, we investigated the effects of YPJ on cognitive deficits and its underlying mechanisms of action in ovariectomized (OVX) mice, an animal model of menopause. OVX mice showed cognitive deficits in the Y-maze, the novel object recognition test, and the Morris water maze. The serum corticosterone (CORT) level was significantly increased in OVX mice. Superoxide dismutase and catalase activities were reduced, while the mRNA expression of IL-1β, IL-6, and TNF-α inflammatory cytokines were up-regulated in the frontal cortex and hippocampus of OVX mice. These alterations were attenuated by daily treatment with either YPJ or 17β-estradiol. HPLC analysis revealed that YPJ contained antioxidant and phytoestrogen constituents including gallic acid, myricetin, quercetin, luteolin, genistein, and coumestrol. These results suggest that YPJ exerts its ameliorative effects on OVX-induced cognitive deficits in part by mitigating HPA axis overactivation, neuroinflammation, and oxidative brain damage. Therefore, YPJ may be a novel alternative therapeutic medicine suitable for the treatment of cognitive deficits during the menopausal transition.

The Effect of Cannabidiol Coated by Nano-Chitosan on Learning and Memory, Hippocampal CB1 and CB2 Levels, and Amyloid Plaques in an Alzheimer's Disease Rat Model

INTRODUCTION

Using nanoparticle (NP) drugs can have better effects on the target tissue in various diseases. Alzheimer's disease (AD) is one of the degenerative neurological diseases that due to its high prevalence, requires the use of more appropriate treatments. Therefore, the aim of this study was consideration of the effect of cannabidiol (CBD) coated by nano-chitosan on learning and memory, hippocampal cannabinoid receptor type 1 (CB1) and cannabinoid receptor type 1 (CB2) levels, and amyloid plaques in an AD rat model.

MATERIAL AND METHODS

Thirty-five male Wistar rats were randomly divided into 5 groups (n = 7 in each): control, Alzheimer's disease model that received the beta-amyloid (Aβ) peptide (Alz), Alz + nano-chitosan (NP) Alz + CBD, and Alz + NP + CBD. Alz was induced by injection of the Aβ1-42 peptide into the hippocampal area cornu ammonis1. After confirmation of Alz, 1 μL of CBD and NP + CBD were administered by oral gavage daily in rats for 1 month. The Morris water maze (MWM) test was used to assess learning and memory of animals. Cresyl violet staining was used for consideration of dead cells. Gene and protein expression of CB1 and CB2 was performed by real-time PCR and immunohistochemistry methods.

RESULTS

Induction of Alz significantly increased Aβ plaques and dead cells compared to the control group (p < 0.001). Results of MWM in the day test show that Alz + NP + CBD significantly decrease escape latency (p < 0.01), travelled distance (p < 0.001), and significantly increased spending time (p < 0.001) compared to the Alz group. Protein expression of CB1 and CB2 significantly increased in Alz + CBD and Alz + NP + CBD compared to the Alz group (p < 0.05).

CONCLUSION

It seems that CBD coated by nano-chitosan has good potential for reducing Aβ plaques, increasing brain CB1 and levels CB2, and improving learning and memory in Alz rats.

Potential Therapeutic Benefits of Honey in Neurological Disorders: The Role of Polyphenols

Honey is the principal premier product of beekeeping familiar to Homo for centuries. In every geological era and culture, evidence can be traced to the potential usefulness of honey in several ailments. With the advent of recent scientific approaches, honey has been proclaimed as a potent complementary and alternative medicine for the management and treatment of several maladies including various neurological disorders such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and multiple sclerosis, etc. In the literature archive, oxidative stress and the deprivation of antioxidants are believed to be the paramount cause of many of these neuropathies. Since different types of honey are abundant with certain antioxidants, primarily in the form of diverse polyphenols, honey is undoubtedly a strong pharmaceutic candidate against multiple neurological diseases. In this review, we have indexed and comprehended the involved mechanisms of various constituent polyphenols including different phenolic acids, flavonoids, and other phytochemicals that manifest multiple antioxidant effects in various neurological disorders. All these mechanistic interpretations of the nutritious components of honey explain and justify the potential recommendation of sweet nectar in ameliorating the burden of neurological disorders that have significantly increased across the world in the last few decades.

Ameliorating Effect of Morin Hydrate on Chronic Restraint Stress-induced Biochemical Disruption, Neuronal, and Behavioral Dysfunctions in BALB/c Mice

INTRODUCTION

Morin hydrate (MH) is a bioflavonoid component of many fruits and vegetables. Our previous research demonstrated that MH provides neuroprotection in mouse models of acute restraint stress and sleep deprivation by attenuating hippocampal neuronal damage and enhancing memory. Based on these findings, our study investigated the role of MH in chronic stress-induced neuronal and biochemical perturbations in BALB/c mice.

METHODS

Male BALB/c mice were divided into 6 groups (n=6). Groups 1 and 2 received vehicle (10 mL/kg normal saline), groups 3-5 received MH (5, 10, 20 mg/kg IP), while group 6 received ginseng (25 mg/kg) daily and 30 minutes afterward were restrained in a plastic cylindrical restrainer for 14 days.

RESULTS

Immobility time in the forced swim test increased in the MH-treated group, indicating an antidepressant-like effect. Also, a reduction in frequency and duration of open arms exploration was observed in the elevated plus-maze (EPM) test in stressed mice, and administration of MH (5, 10, 20 mg/kg, IP) reversed these effects. An increase in blood levels of glucose, triglycerides, total cholesterol, and brain malondialdehyde and nitrite levels was observed in the stressed groups, which was reversed by MH. Furthermore, MH reversed the stress-induced reduction in HDL cholesterol and glutathione (GSH) levels and attenuated stress-induced alterations in the prefrontal cortex and hippocampus.

CONCLUSION

Our findings suggest that MH attenuated chronic restraint stress-behavioral and biochemical perturbations, probably due to its capability to decrease oxidative stress and brain neuronal damage.

HIGHLIGHTS

Chronic stress perturbs physiological and psychological homeostasis;Morin hydrate normalized chronic stress-induced biochemical disruptions;Morin hydrate attenuated structural changes in prefrontal cortex and hippocampus.

PLAIN LANGUAGE SUMMARY

Stress is a state of being overwhelmed by demands exceeding the personal and social means of coping. Exposure to excessive stress has resulted in disruption of neurochemical and physiological processes, which sometimes manifest as behavioural abnormalities. Therefore to cope with the stressful life style, there is need to develop a therapeutic agent of plant origin. Morin hydrate is a flavonoid with known antioxidant and neuroprotective properties; however, its effect in a stressful condition has not been studies. The study thus evaluated ameliorating effect of Morin hydrate on chronic restraint stress-induced biochemical disruption, neuronal and behavioral dysfunctions in BALB/c mice. To achieve this, mice were exposed to chronic restraint stress protocol for fourteen days. Behavioural changes were examined using various techniques. The vital parameters like antioxidant, glucose and nitrite levels were also taken. Our findings show that Morin hydrate prevented behavioral abnormalities and damage to the brain cells. It also inhibited stress-induced biochemical disturbance.

Bioinformatics and Network-based Approaches for Determining Pathways, Signature Molecules, and Drug Substances connected to Genetic Basis of Schizophrenia etiology

Knowledge of heterogeneous etiology and pathophysiology of schizophrenia (SZP) is reasonably inadequate and non-deterministic due to its inherent complexity and underlying vast dynamics related to genetic mechanisms. The evolution of large-scale transcriptome-wide datasets and subsequent development of relevant, robust technologies for their analyses show promises toward elucidating the genetic basis of disease pathogenesis, its early risk prediction, and predicting drug molecule targets for therapeutic intervention. In this research, we have scrutinized the genetic basis of SZP through functional annotation and network-based system biology approaches. We have determined 96 overlapping differentially expressed genes (DEGs) from 2 microarray datasets and subsequently identified their interconnecting networks to reveal transcriptome signatures like hub proteins (FYN, RAD51, SOCS3, XIAP, AKAP13, PIK3C2A, CBX5, GATA3, EIF3K, and CDKN2B), transcription factors and miRNAs. In addition, we have employed gene set enrichment to highlight significant gene ontology (e.g., positive regulation of microglial cell activation) and relevant pathways (such as axon guidance and focal adhesion) interconnected to the genes associated with SZP. Finally, we have suggested candidate drug substances like Luteolin HL60 UP as a possible therapeutic target based on these key molecular signatures.

The Effect of Prosopis farcta and Its Bioactive Luteolin on the Hippocampus of Mice after Induced Ischemia Reperfusion

Background

Ischemia plays an important role in increasing damage to the nervous system. This study aimed to evaluate the effect of Prosopis farcta (PFE) and its bioactive luteolin (Lu) and forced swimming exercise on the hippocampus of mice after induced ischemia reperfusion.

Methods

The bioactive component of PFE (Lu) was identified by HPLC. Fifty-six male mice were divided into different groups. Ischemia was induced by ligation of the common carotid artery. After mice training (swimming exercise, 8 weeks) and consuming PFE and Lu, the mice's memory ability was evaluated in the shuttle box. Histological examination was performed by Nissel staining and immunohistochemistry.

Results

Results showed that the ischemic mice exercised and treated with PFE and Lu had higher step-through latency (STL) compared with the nonexercised mice, and this was confirmed with time spent in the dark compartment (TDC). The number of dark cells in the ischemic group exercising and receiving PFE and Lu decreased compared to that of the other groups in the hippocampus. DCX protein expression was increased in nonexercised groups compared to that of the exercised groups and those treated with PFE and Lu, while NeuN decreased.

Conclusions

Forced swimming exercise following ischemia, as well as consumption of PFE and Lu, has reduced cell death and increased neurogenesis in the hippocampus and thus may help improve memory in ischemia.

The druggability of bitter taste receptors for the treatment of neurodegenerative disorders

The delivery of therapeutic drugs to the brain remains a major pharmacology challenge. A complex system of chemical surveillance to protect the brain from endogenous and exogenous toxicants at brain barriers hinders the uptake of many compounds with significant in vitro and ex vivo therapeutic properties. Despite the advances in the field in recent years, the components of this system are not completely understood. Recently, a large group of chemo-sensing receptors, have been identified in the blood-cerebrospinal fluid barrier. Among these chemo-sensing receptors, bitter taste receptors (TAS2R) hold promise as potential drug targets, as many TAS2R bind compounds with recognized neuroprotective activity (quercetin, resveratrol, among others). Whether activation of TAS2R by their ligands contributes to their diverse biological actions described in other cells and tissues is still debatable. In this review, we discuss the potential role of TAS2R gene family as the mediators of the biological activity of their ligands for the treatment of central nervous system disorders and discuss their potential to counteract drug resistance by improving drug delivery to the brain.

The Ameliorative Impact of Centella asiatica on the Working Memory Deficit in Streptozotocin-induced Rat Model of Alzheimer Disease

Introduction

Alzheimer disease (AD) is a complex neurodegenerative disorder with a progressive nature leading to neural damage and cognitive and memory deficit. The present study investigated the neuroprotective effects of Centella asiatica (CA) in Streptozotocin (STZ)-induced rat model of memory impairment and neuronal damage.

Methods

The intracerebroventricular infusion of STZ (3 mg/rat) or saline (as the vehicle) was performed on days 1 and 3. CA (150 and 300 mg/kg/d) was administered through oral gavage for 21 days after model induction. We used the Y-maze test to assess the working memory-related performances of animals. Rats were then sacrificed, and their hippocampi were harvested for evaluation of neuronal density in the cornu ammonis (CA1, CA2, CA3) and Dentate Gyrus (DG) regions using stereology technique.

Results

The intracerebroventricular infusion of STZ caused significant working memory impairment demonstrated in the Y-maze apparatus, with a significant decrease in alternative behavior compared to control animals (40.67±2.04 vs 73.00±1.88, P<0.0001). Oral administration of CA (150 and 300 mg/kg each day) for 21 days significantly improved STZ-induced working memory deficit (55.33±3.34 and 57.17±3.81 vs 40.67±2.04, P<0.013, P<0.004, respectively). Furthermore, 21 days of consecutive administration of CA significantly ameliorated STZ-induced neuronal loss in the CA1, CA2, and DG subfields of the hippocampus.

Conclusion

Overall, these data demonstrate that CA increases neuronal density and improves cognitive impairment in the STZ-induced rat model of AD, thereby having promising therapeutic potential for neurodegenerative disorders. Accordingly, further studies are needed to determine the exact molecular mechanism of CA protective effects in brain disorders, particularly AD.

Highlights

Centella asiatica (CA) improved the STZ-induced working memory deficit.CA could prevent hippocampal neural cell loss dose-dependent manner.CA improved memory through mitigating neuronal loss in hippocampus.

Plain Language Summary

Memory loss is the first signs of dementia. It is well known that a healthy diet might be as good for your brain as it is for your heart. Numerous traditionally used medicinal herbs could significantly affect key events culminating in dementia and Alzheimer's disease. Centella asiatica, commonly known as Gotu Kola or Indian Pennywort, is a tropical, medicinal plant native to Southeast Asian countries. It is one of the becoming popular medicinal plants in the world. Centella asiatica (CA) is widely used in different traditional medicine systems for various purposes, such as reducing blood pressure, memory enhancement, and promoting longevity. In the present study, we tested the possible impact of CA leaf and stem extract in an animal model of memory damage. Memory impairment was induced in adult rats by intracerebral infusion of a neurotoxin chemical. Then, the memory-impaired animals were orally treated with 150-300 mg/kg of CA extract for 21 days. Finally, we tested their working memory by placing them in a Y-maze apparatus. Furthermore, their most involved brain part (hippocampus) was dissected, and its cell density was evaluated. Our findings exhibited that CA treatment considerably improved rats' memory performance, indicating by enhancing working memory score in the Y-maze task. In addition, CA treatment significantly prevented neuronal cell loss in the hippocampus of memory-impaired rats. This study shows that CA has beneficial effects on memory and cognitive function.

Magnolol attenuates the locomotor impairment, cognitive deficit, and neuroinflammation in Alzheimer's disease mice with brain insulin resistance via up-regulating miR-200c

In this study, we aimed to investigate the effect of Magnolol on Alzheimer’s disease (AD). After the model of streptozotocin-induced AD mice with brain insulin resistance was established, the mice were treated with Magnolol or miR-200c antagomiR. The abilities of ambulations, rearings, discrimination, spatial learning, and memory were evaluated by open-field test (OFT), novel object recognition (NOR), and morris water maze (MWM) tests. The levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and miR-200c in the mice hippocampus were evaluated by enzyme-linked immunosorbent assay, Western blot, or Quantitative real-time Polymerase Chain Reaction. In AD mice model, streptozotocin induced the locomotor impairment and cognitive deficit, up-regulated levels of MDA, TNF-α, IL-6, and CRP, while down-regulated levels of GSH, SOD, and miR-200c. Magnolol increased the rearings numbers and discrimination index of AD mice in OFT and NOR tests. Magnolol increased the number of entries in the target quadrant and time spent in the target quadrant and decreased the escape latency of AD mice in the MWM test. Magnolol also down-regulated the levels of MDA, TNF-α, IL-6, and CRP, and up-regulated the levels of GSH, SOD, and miR-200c in the hippocampus tissues of AD mice. However, miR-200c antagomiR did the opposite and further offset the effects of the Magnolol on AD mice. Magnolol attenuated the locomotor impairment, cognitive deficit, and neuroinflammatory in AD mice with brain insulin resistance via up-regulating miR-200c.

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.

Luteolin Modulates Neural Stem Cells Fate Determination: In vitro Study on Human Neural Stem Cells, and in vivo Study on LPS-Induced Depression Mice Model

Luteolin is a natural flavone with neurotrophic effects observed on different neuronal cell lines. In the present study, we aimed to assess the effect of luteolin on hNSCs fate determination and the LPS-induced neuroinflammation in a mouse model of depression with astrocytogenesis defect. hNSCs were cultured in basal cell culture medium (control) or medium supplemented with luteolin or AICAR, a known inducer of astrogenesis. A whole-genome transcriptomic analysis showed that luteolin upregulated the expressions of genes related to neurotrophin, dopaminergic, hippo, and Wnt signaling pathways, and downregulated the genes involved in p53, TNF, FOXO, and Notch signaling pathways. We also found that astrocyte-specific gene GFAP, as well as other genes of the key signaling pathways involved in astrogenesis such as Wnt, BMP, and JAK-STAT pathways were upregulated in luteolin-treated hNSCs. On the other hand, neurogenesis and oligodendrogenesis-related genes, TUBB3, NEUROD 1 and 6, and MBP, were downregulated in luteolin-treated hNSCs. Furthermore, immunostaining showed that percentages of GFAP+ cells were significantly higher in luteolin- and AICAR-treated hNSCs compared to control hNSCs. Additionally, RT-qPCR results showed that luteolin upregulated the expressions of GFAP, BMP2, and STAT3, whereas the expression of TUBB3 remained unchanged. Next, we evaluated the effects of luteolin in LPS-induced mice model of depression that represents defects in astrocytogenesis. We found that oral administration of luteolin (10 mg/Kg) for eight consecutive days could decrease the immobility time on tail suspension test, a mouse behavioral test measuring depression-like behavior, and attenuate LPS-induced inflammatory responses by significantly decreasing IL-6 production in mice brain-derived astrocytes and serum, and TNFα and corticosterone levels in serum. Luteolin treatment also significantly increased mature BDNF, dopamine, and noradrenaline levels in the hypothalamus of LPS-induced depression mice. Though the behavioral effects of luteolin did not reach statistical significance, global gene expression analyses of mice hippocampus and brain-derived NSCs highlighted the modulatory effects of luteolin on different signaling pathways involved in the pathophysiology of depression. Altogether, our findings suggest an astrocytogenic potential of luteolin and its possible therapeutic benefits in neuroinflammatory and neurodegenerative diseases. However, further studies are required to identify the specific mechanism of action of luteolin.

Toxic Substance-induced Hippocampal Neurodegeneration in Rodents as Model of Alzheimer’s Dementia

BACKGROUND: Alzheimer’s Dementia (AD) cases are increasing with the global elderly population. To study the part of the brain affected by AD, animal models for hippocampal degeneration are still necessary to better understand AD pathogenesis and develop treatment and prevention measures. AIM: This study was a systematic review of toxic substance-induced animal models of AD using the Morris Water Maze method in determining hippocampal-related memory impairment. Our aim was reviewing the methods of AD induction using toxic substances in laboratory rodents and evaluating the report of the AD biomarkers reported in the models. METHODS: Data were obtained from articles in the PubMed database, then compiled, categorized, and analyzed. Eighty studies published in the past 5 years were included for analysis. RESULTS AND DISCUSSION: The most widely used method was intracerebroventricular injection of amyloid-β _substances. However, some less technically challenging techniques using oral or intraperitoneal administration of other toxic substances also produce successful models. Instead of hippocampal neurodegeneration, many studies detected biomarkers of the AD pathological process while some reported inflammation, oxidative stress, neurotrophic factors, and changes of cholinergic activity. Female animals were underrepresented despite a high incidence of AD in women. CONCLUSION: Toxic substances may be used to develop AD animal models characterized with appropriate AD pathological markers. Characterization of methods with the most easy-handling techniques and more studies in female animal models should be encouraged.

Neuroprotective Potential of Mung Bean (Vigna radiata L.) Polyphenols in Alzheimer's Disease: A Review

Mung bean contains various neuroprotective polyphenols, so it might be a healthy food for Alzheimer's disease (AD) prevention. Totally, 19 major phenolic compounds were quantified in mung bean, including 10 phenolic acids and 9 flavonoids. After summarizing their contents and effective doses in rodent AD models, it was speculated that vitexin, isovitexin, sinapic acid, and ferulic acid might be the major bioactive compounds for mung bean-mediated neuroprotection. The mechanisms involved inhibition of β-amyloidogenesis, tau hyperphosphorylation, oxidative stress, and neuroinflammation, and promotion of autophagy and acetylcholinesterase enzyme activity. Notably, the neuroprotective phenolic profile in mung bean changed after germination, with decreased vitexin and isovitexin, and increased rutin, isoquercitrin, isorhamnetin, and caffeic acid detected. However, only studies of individual phenolic compounds in mung bean are published at present. Hence, further studies are needed to elucidate the neuroprotective activities and mechanisms of extractions of mung bean seeds and sprouts, and the synergism between different phenolic compounds.

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.