Diosmin reduces cerebral Aβ levels, tau hyperphosphorylation, neuroinflammation, and cognitive impairment in the 3xTg-AD mice

Evaluation of the Effect of Loratadine versus Diosmin/Hesperidin Combination on Vinca Alkaloids-Induced Neuropathy: A Randomized Controlled Clinical Trial

Neurological injury is a crucial problem that interferes with the therapeutic use of vinca alkaloids as well as the quality of patient life. This study was conducted to assess the impact of using loratadine or diosmin/hesperidin on neuropathy induced by vinca alkaloids. Patients were randomized into one of three groups as follows: group 1 was the control group, group 2 received 450 mg diosmin and 50 mg hesperidin combination orally twice daily, and group 3 received loratadine 10 mg orally once daily. Subjective scores (numeric pain rating scale, douleur neuropathique 4, and functional assessment of cancer therapy/gynecologic oncology group-neurotoxicity (FACT/GOG-Ntx) scores), neuroinflammation biomarkers, adverse drug effects, quality of life, and response to chemotherapy were compared among the three groups. Both diosmin/hesperidin and loratadine improved the results of the neurotoxicity subscale in the FACT/GOG-Ntx score (p < 0.001, p < 0.01 respectively) and ameliorated the upsurge in neuroinflammation serum biomarkers. They also reduced the incidence and timing of paresthesia (p = 0.001 and p < 0.001, respectively) and dysuria occurrence (p = 0.042). Both loratadine and diosmin/hesperidin attenuated the intensity of acute neuropathy triggered by vinca alkaloids. Furthermore, they did not increase the frequency of adverse effects or interfere with the treatment response.

Natural polyphenol: Their pathogenesis-targeting therapeutic potential in Alzheimer's disease

Alzheimer's disease (AD) is a detrimental neurodegenerative disease affecting the elderly. Clinically, it is characterized by progressive memory decline and subsequent loss of broader cognitive functions. Current drugs provide only symptomatic relief but do not have profound disease-modifying effects. There is an unmet need to identify novel pharmacological agents for AD therapy. Neuropathologically, the characteristic hallmarks of the disease are extracellular senile plaques containing amyloid β-peptides and intracellular neurofibrillary tangles containing hyperphosphorylated microtubule-associated protein tau. Simultaneously, oxidative stress, neuroinflammation and mitochondrial dysfunction in specific brain regions are early events during the process of AD pathologic changes and are associated with Aβ/tau toxicity. Here, we first summarized probable pathogenic mechanisms leading to neurodegeneration and hopefully identify pathways that serve as specific targets to improve therapy for AD. We then reviewed the mechanisms that underlie disease-modifying effects of natural polyphenols, with a focus on nuclear factor erythroid 2-related factor 2 activators for AD treatment. Lastly, we discussed challenges in the preclinical to clinical translation of natural polyphenols. In conclusion, there is evidence that natural polyphenols can be therapeutically useful in AD through their multifaceted mechanism of action. However, more clinical studies are needed to confirm these effects.

Diosmetin derivatives as multifunctional anti-AD ligands: Design, synthesis, and biological evaluation

With the increasing aging population, rational design of drugs for Alzheimer's disease (AD) treatment has become an important research area. Based on the multifunctional design strategy, four diosmetin derivatives (1-4) were designed, synthesized, and characterized by 1H NMR, 13C NMR, and MS. Docking study was firstly applied to substantiate the design strategies and then the biological activities including cholinesterase inhibition, metal chelation, antioxidation and β-amyloid (Aβ) aggregation inhibition in vitro were evaluated. The results showed that 1-4 had good acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibition, metal chelation (selective chelation of Cu2+ ions), antioxidation, self-induced, Cu2+-induced, and AChE-induced Aβ aggregation inhibition activities, and suitable blood-brain barrier (BBB) permeability. Especially, compound 3 had the strongest inhibitory effect on AChE (10-8 M magnitude) and BuChE (10-7 M magnitude) and showed the best inhibition on AChE-induced Aβ aggregation with 66.14% inhibition ratio. Furthermore, compound 3 could also reduce intracellular reactive oxygen species (ROS) levels in Caenorhabditis elegans and had lower cytotoxicity. In summary, 3 might be considered as a potential multifunctional anti-AD ligand.

Açai pulp improves cognition and insulin sensitivity in obese mice

SCOPE

Obesity and insulin resistance constitute risk factors for the development of tauopathies and other neurodegenerative diseases. (Poly)phenol compounds are under study for its role in protecting effects against neural injuries and degeneration. Here, we investigated the effect of Amazonian açai pulp (AP) intake in the prevention of memory and cognitive impairment resulting from a high-fat diet intake in mice.

METHODS AND RESULTS

Obesity and insulin resistance was induced with a high-fat diet and supplemented with 2% AP to investigate peripheral insulin resistance, recognition memory and tau protein stability via AKT/GSK3-β signaling pathway. The consumption of AP for 70 days improved peripheral insulin sensitivity and phosphorylation of AKT/GSK3-β in mice hippocampi. The animals fed high-fat diets supplemented with AP showed better performance in the novel object recognition test (NOR) in comparison to the H group. Catalase activity and reduced glutathione (GSH) values were improved in the treated mice.

CONCLUSIONS

These results suggest that the supplementation of AP can attenuate the effects of high-fat diet consumption in peripheral insulin resistance and improve cognitive behavior.

Diosmin ameliorates LPS-induced depression-like behaviors in mice: Inhibition of inflammation and oxidative stress in the prefrontal cortex

Diosmin is a flavone glycoside with a confirmed therapeutic effectiveness on the chronic venous disorders. In this paper, the classical mouse depression model induced by LPS was established to explore the effect of Diosmin on depression. Firstly, we found that Diosmin could inhibit the inflammation and neuronal damage in the prefrontal cortex (PFC) of mice, and thus alleviating the LPS-induced depressive-like behaviors. Specifically, Diosmin treatment significantly suppressed the secretion of pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β), reduced the activation of microglia, and inhibited the expression of NLRP3 inflammasome and its downstream effector caspase-1 in both PFC of mice and BV2 microglial cells exposed to LPS. Then, we demonstrated that pretreatment with Diosmin dramatically suppressed the LPS-induced oxidative stress in the PFC of mice, manifested in the decrease of reactive oxygen species and malondialdehyde while increase of catalase activity. Consistently, Diosmin also alleviated the oxidative stress in BV2 cells exposed to LPS. Finally, we confirmed that Diosmin effectively suppressed the activation of NF-κB signaling pathway in the PFC of LPS-treated mice. Further in vitro experiments also verified that Diosmin could prevent the p65 transposition to nucleus in LPS-treated BV2 cells, suggesting that the antidepressant effects of Diosmin are partially mediated by blocking of NF-κB signaling. Taken together, this study proposes the potential antidepressant effect of Diosmin, which provides useful support to the development of new therapies for depression.

Flavonoids and fibrate modulate apoE4-induced processing of amyloid precursor protein in neuroblastoma cells

Introduction

Apolipoprotein (apo) E4, being a major genetic risk factor for Alzheimer's disease (AD), is actively involved in the proteolytic processing of amyloid precursor protein (APP) to amyloid β (Aβ) peptide, the principle constituent of amyloid plaques in Alzheimer Disease (AD) patients. ApoE4 is believed to affect APP processing through intracellular cholesterol homeostasis, whereas lowering the cholesterol level by pharmacological agents has been suggested to reduce Aβ production. This study has investigated the effects of hypolipidemic agents fenofibrate, and the flavonoids-naringenin and diosmetin-on apoE4-induced APP processing in rat neuroblastoma cells stably transfected with human wild-type APP 695 (B103-hAPP695wt).

Results

B103-hAPP695wt cells were pretreated with different doses of flavonoids and fenofibrate for 1 h prior to apoE4 exposure for 24 h. ApoE4-induced production of intra- and extracellular Aβ peptides has been reduced with fenofibrate, naringenin, and diosmetin treatments. Pretreatment with diosmetin has significantly reduced apoE4-induced full-length APP (fl- APP) expression, whereas naringenin and fenofibrate had no effect on it. In addition, the increase in the apoE4-induced secretion of sAPPtotal and sAPPα has been dose-dependently reduced with drug pretreatment. On the other hand, the decrease in the expression of both APP-carboxy terminal fragments (CTF)-α and -β (generated by the α- or β-secretase cleavage of APP) by apoE4 was dose-dependently increased in cells pretreated with fenofibrate and naringenin but not diosmetin.

Conclusion

Thus, we suggest that fenofibrate, naringenin, and diosmetin treatments can reduce apoE4- induced Aβ production by distinct mechanisms that may prove useful in developing drugs for AD patients.

Polyphenolic flavonoid compounds act as the inhibitory potential of aggregation process: Implications for the prevention and therapeutics against FALS-associated D101G SOD1 mutant

Aggregation of proteins is a biological phenomenon caused by misfolded proteins. Human superoxide dismutase (hSOD1) misfolding and aggregation underlie the neurological illness amyotrophic lateral sclerosis (ALS). The most significant contributing factor to ALS is genetic point mutations in SOD1. particularly, D101G mutant is the most harmful because it significantly reduces the life expectancy of patients. Subsequently, the use of natural polyphenolic flavonoids is strongly recommended to reduce the amyloidogenic behavior of protopathic proteins. In this study, using computational parameters such as protein-ligand interaction and molecular dynamics (MD) simulation analyses, we are trying to identify a pharmacodynamically promising flavonoid compound that can effectively inhibit the pathogenic behavior of the D101G mutant. Epigallocatechin-gallate (EGCG), Hesperidin, Isorhamnetin, and Diosmetin were identified as potential leads in a preliminary screening of flavonoids to anti-amyloid action. The results of MD showed that the binding of flavonoids to D101G mutant caused changes in stability, hydrophobicity of protein, and flexibility, as well as significantly led to the restoration of lost hydrogen bonds. Secondary structure analysis showed that protein destabilization and the increased propensity of β-sheet caused by the mutation were restored to the wild-type state upon binding of flavonoids. Besides, to differentiate aggregation, we elucidated alterations in the free energy landscape (FEL) and dynamic cross-correlation matrix (DCCM) of WT-SOD1 and mutant (unbound /bound) states. Among flavonoids, Epigallocatechin-gallate and Hesperidin had the most therapeutic efficacy against the D101G mutant. Therefore, Epigallocatechin-gallate and Hesperidin promise considerable therapeutic potential to develop highly effective inhibitors in reducing fatal and irreversible ALS.

Fighting against amyotrophic lateral sclerosis (ALS) with flavonoids: a computational approach to inhibit superoxide dismutase (SOD1) mutant aggregation

Protein aggregation is a biological process that occurs when proteins misfold. Misfolding and aggregation of human superoxide dismutase (hSOD1) cause a neurodegenerative disease called amyotrophic lateral sclerosis (ALS). Among the mutations occurring, targeting the E21K mutation could be a good choice to understand the pathological mechanism of SOD1 in ALS, whereof it significantly reduces life hopefulness in patients. Naturally occurring polyphenolic flavonoids have been suggested as a way to alleviate the amyloidogenic behavior of proteins. In this study, computational tools were used to identify promising flavonoid compounds that effectively inhibit the pathogenic behavior of the E21K mutant. Initial screening identified Pelargonidin, Curcumin, and Silybin as promising leads. Molecular dynamics (MD) simulations showed that the binding of flavonoids to the mutated SOD1 caused changes in the protein stability, hydrophobicity, flexibility, and restoration of lost hydrogen bonds. Secondary structure analysis indicated that the protein destabilization and the increased propensity of β-sheet caused by the mutation were restored to the wild-type state upon binding of flavonoids. Free energy landscape (FEL) analysis was also used to differentiate aggregation, and results showed that Silybin followed by Pelargonidin had the most therapeutic efficacy against the E21K mutant SOD1. Therefore, these flavonoids hold great potential as highly effective inhibitors in mitigating ALS's fatal and insuperable effects.Communicated by Ramaswamy H. Sarma.

Angiotensin II Receptor Blockers Reduce Tau/Aß42 Ratio: A Cerebrospinal Fluid Biomarkers’ Case-Control Study

(1) Background: The role of antihypertensives in Alzheimer’s Disease (AD) prevention is controversial. This case-control study aims to assess whether antihypertensive medication has a protective role by studying its association with amyloid and tau abnormal levels. Furthermore, it suggests a holistic view of the involved pathways between renin-angiotensin drugs and the tau/amyloidß42 ratio (tau/Aß42 ratio); (2) Methods: The medical records of the participant patients were reviewed, with a focus on prescribed antihypertensive drugs and clinical variables, such as arterial blood pressure. The Anatomical Therapeutic Chemical classification was used to classify each drug. The patients were divided into two groups: patients with AD diagnosis (cases) and cognitively healthy patients (control); (3) Results: Age and high systolic blood pressure are associated with a higher risk of developing AD. In addition, combinations of angiotensin II receptor blockers are associated with a 30% lower t-tau/Aß42 ratio than plain angiotensin-converting enzyme inhibitor consumption; (4) Conclusions: Angiotensin II receptor blockers may play a potential role in neuroprotection and AD prevention. Likewise, several mechanisms, such as the PI3K/Akt/GSK3ß or the ACE1/AngII/AT1R axis, may link cardiovascular pathologies and AD presence, making its modulation a pivotal point in AD prevention. The present work highlights the central pathways in which antihypertensives may affect the presence of pathological amyloid and tau hyperphosphorylation.

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.

Lipopolysaccharide Exacerbates Ketamine-Induced Psychotic-Like Behavior, Oxidative Stress, and Neuroinflammation in Mice: Ameliorative Effect of Diosmin

Schizophrenia, a neuropsychiatric disorder has been associated with aberrant neurotransmission affecting behaviors, social preference, and cognition. Limitations in understanding its pathogenesis via the dopamine hypothesis have engendered other hypotheses such as the glutamate hypothesis. That antagonism of the N-methyl-D-aspartate receptor (NMDAR) elicits schizophrenia-like behaviors indistinguishable from the disorder in animal and human models. There are growing concerns that redox imbalance and neuro-immuno dysfunction may play role in aggravating the symptomologies of this disorder. This 14-day treatment study was designed to investigate the effect of diosmin on lipopolysaccharide (LPS) plus ketamine (NMDAR antagonist). Mice were divided into 4 groups (n = 6). Group 1 was administered 5% DMSO (10 mL/kg, i.p) while group 2-4 received LPS (0.1 mg/kg, i.p) daily for 14 days. Diosmin (50 mg/kg, i.p) and risperidone (0.5 mg/kg, i.p) were given to groups 3 and 4 respectively. Groups 2-4 were given KET (20 mg/kg, i.p.) daily from days 8-14. Behavioral tests were done 30 min after the last dose, and oxidative stress and neuroinflammatory maker were assayed. LPS plus ketamine-induced hyperlocomotion, stereotypy, decreased social preference, and memory impairment. Furthermore, LPS plus-ketamine-induced oxidative stress (reduced GSH, CAT, SOD, and increased MDA and nitrite levels) and marked pro-inflammatory cytokines TNF-α and IL-6 suggesting neuroinflammation. However, diosmin attenuated behavioral deficits and improved memory. Additionally, diosmin potentiated antioxidant level via increased GSH, CAT, and SOD while reducing MDA and nitrite levels. Finally, diosmin reduced TNF-α and IL-6 suggesting anti-neuro-immuno activity. Conclusively, diosmin attenuated LPS plus ketamine-induced behavioral deficits, oxidative stress, neuroinflammation, and improved memory.

Flavonoids as G Protein-coupled Receptors Ligands: New Potential Therapeutic Natural Drugs

G protein coupled receptors (GPCRs) are among the largest family of cell surface receptors found in the human genome. They govern a wide range of physiological responses in both health and diseases, making them one of the potential targeted surface receptors for pharmaceuticals. Flavonoids can modulate GPCRs activity by acting as allosteric ligands. They can either enhance or reduce the GPCR's effect. Emerging research shows that individual flavonoids or mixtures of flavonoids from plant extracts can have relevant pharmacological effects against a number of diseases, particularly by influencing GPCRs. In the present review, we are considering to give a comprehensive overview of flavonoids and related compounds that exhibit GPCRs activity and to further explore which beneficial structural features. Molecular docking was used to strengthen experimental evidence and describe flavonoid-GPCRs interactions at molecular level.

[The glymphatic system in the brain - neurobiology and clinical pathology]

Given new information about the neurobiology of the processes of removal of waste products of the brain, consisting of the lymphatic vessels into the dura and the glial-lymphatic (glymphatic) system. The role of astrocytes and water-conducting channels located on them in cell membranes formed by the protein aquaporin-4 is emphasized. The connection between the functioning of the glymphatic system and the slow phase of sleep is discussed. Possible mechanisms for the development of cognitive impairments in violation of the function of the glymphatic system and a delay in the elimination of β-amyloid are shown. Directions of pathogenetic therapy are given.

Therapeutic approaches of nutraceuticals in the prevention of Alzheimer's disease

Alzheimer's disease (AD) is a neurological illness that causes memory loss over time. Currently, available pharmaceutical medicines and products are limited, and they have side effects at a higher price. Researchers and scientists have observed significant effects of nutraceuticals. Various preclinical and clinical studies were investigated for the Anti-Alzheimer's activity of nutraceuticals. The increasing ability of the pathogenesis of AD has led to the analysis of novel therapeutic targets, including the pathophysiological mechanisms and distinct cascades. So, current improvement will show the most adequate and prominent nutraceuticals and suggested concise mechanisms involving autophagy regulation, anti-inflammatory, antioxidant, mitochondrial homeostasis, and others. The effects of nutraceuticals cannot be ignored; it is important to investigate high-quality clinical trials. Given the potential of nutraceuticals to battle AD as multi-targeted therapies, it's vital to evaluate them as viable lead compounds for drug discovery and development. To the best of the authors 'knowledge, modification of blood-brain barrier permeability, bioavailability, and aspects of randomized clinical trials should be considered in prospective investigations. PRACTICAL APPLICATIONS: Advancements in molecular diagnostic and fundamentals have implemented particular usefulness for drug evaluation. An excess of experimental knowledge occurs regarding the effect of nutraceuticals on AD. There are various preclinical and clinical studies that have been done on nutraceuticals. In addition, various substitute inhibit and enhance some pathophysiological levels associated with AD. Nutraceuticals are easily available and have fewer side effects with cost-effective advantages. However, further investigations and clinical trials are required to encourage its effect on disease.

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.

Protective Effects of Flavonoids against Alzheimer's Disease: Pathological Hypothesis, Potential Targets, and Structure-Activity Relationship

Alzheimer’s disease (AD) is a neurodegenerative disease with high morbidity and mortality, for which there is no available cure. Currently, it is generally believed that AD is a disease caused by multiple factors, such as amyloid-beta accumulation, tau protein hyperphosphorylation, oxidative stress, and inflammation. Multitarget prevention and treatment strategies for AD are recommended. Interestingly, naturally occurring dietary flavonoids, a class of polyphenols, have been reported to have multiple biological activities and anti-AD effects in several AD models owing to their antioxidative, anti-inflammatory, and anti-amyloidogenic properties. In this review, we summarize and discuss the existing multiple pathogenic factors of AD. Moreover, we further elaborate on the biological activities of natural flavonoids and their potential mode of action and targets in managing AD by presenting a wide range of experimental evidence. The gathered data indicate that flavonoids can be regarded as prophylactics to slow the advancement of AD or avert its onset. Different flavonoids have different activities and varying levels of activity. Further, this review summarizes the structure–activity relationship of flavonoids based on the existing literature and can provide guidance on the design and selection of flavonoids as anti-AD drugs.

Oligomeropathies, inflammation and prion protein binding

The central role of oligomers, small soluble aggregates of misfolded proteins, in the pathogenesis of neurodegenerative disorders is recognized in numerous experimental conditions and is compatible with clinical evidence. To underline this concept, some years ago we coined the term oligomeropathies to define the common mechanism of action of protein misfolding diseases like Alzheimer, Parkinson or prion diseases. Using simple experimental conditions, with direct application of synthetic β amyloid or α-synuclein oligomers intraventricularly at micromolar concentrations, we could detect differences and similarities in the biological consequences. The two oligomer species affected cognitive behavior, neuronal dysfunction and cerebral inflammatory reactions with distinct mechanisms. In these experimental conditions the proposed mediatory role of cellular prion protein in oligomer activities was not confirmed. Together with oligomers, inflammation at different levels can be important early in neurodegenerative disorders; both β amyloid and α-synuclein oligomers induce inflammation and its control strongly affects neuronal dysfunction. This review summarizes our studies with β-amyloid or α-synuclein oligomers, also considering the potential curative role of doxycycline, a well-known antibiotic with anti-amyloidogenic and anti-inflammatory activities. These actions are analyzed in terms of the therapeutic prospects.

Diosmetin Targeted at Peroxisome Proliferator-Activated Receptor Gamma Alleviates Advanced Glycation End Products Induced Neuronal Injury

The present study aimed to evaluate the role of diosmetin in alleviating advanced glycation end products (AGEs)-induced Alzheimer’s disease (AD)-like pathology and to clarify the action mechanisms. Before stimulation with AGEs (200 μg/mL), SH-SY5Y cells were treated with diosmetin (10 μmol/L), increasing cell viability. The induction of AGEs on the reactive oxygen species overproduction and downregulation of antioxidant enzyme activities, including superoxide dismutase, glutathione peroxidase, and catalase, were ameliorated by diosmetin. Amyloid precursor protein upregulation, accompanied by increased production of amyloid-β, caused by AGEs, was reversed by diosmetin. In the presence of diosmetin, not only β-site amyloid precursor protein cleaving enzyme1 expression was lowered, but the protein levels of insulin-degrading enzyme and neprilysin were elevated. Diosmetin protects SH-SY5Y cells from endoplasmic reticulum (ER) stress response to AGEs by suppressing ER stress-induced glucose regulated protein 78, thereby downregulating protein kinase R-like endoplasmic reticulum kinase, eukaryotic initiation factor 2 α, activating transcription factor 4, and C/EBP homologous protein. Diosmetin-pretreated cells had a lower degree of apoptotic DNA fragmentation; this effect may be associated with B-cell lymphoma (Bcl) 2 protein upregulation, Bcl-2-associated X protein downregulation, and decreased activities of caspase-12/-9/-3. The reversion of diosmetin on the AGEs-induced harmful effects was similar to that produced by pioglitazone. The peroxisome proliferator-activated receptor (PPAR)γ antagonist T0070907 (5 μmol/L) abolished the beneficial effects of diosmetin on AGEs-treated SH-SY5Y cells, indicating the involvement of PPARγ. We conclude that diosmetin protects neuroblastoma cells against AGEs-induced ER injury via multiple mechanisms and may be a potential option for AD.

Potential of flavonoids as anti-Alzheimer's agents: bench to bedside

Developing therapies for neurodegenerative diseases are challenging because of the presence of blood-brain barrier and Alzheimer being one of the commonest and uprising neurodegenerative disorders possess the need for developing novel therapies. Alzheimer's is attributed to be the sixth leading cause of death in the USA and the number of cases is estimated to be increased from 58 million in 2021 to 88 million by 2050. Natural drugs have benefits of being cost-effective, widely available, fewer side effects, and immuno-booster can be useful in managing Alzheimer. Flavonoids can slow the neuronal degeneration as they have shown activity in central nervous system and are able to cross the blood-brain barrier. These can be easily extracted from fruits, vegetable, and plants. In Alzheimer disease, flavonoids scavenges the reactive oxygen species and reduces the production of amyloid beta protein. Agents from sub-classes of flavonoids such as flavanones, flavanols, flavones, flavonols, anthocyanins, and isoflavones having pharmacological action in treating Alzheimer disease are discussed in this review.

Exploring Sex-Related Differences in Microglia May Be a Game-Changer in Precision Medicine

One area of microglial biology that has been relatively neglected until recently is sex differences and this is in spite of the fact that sex is a risk factor in several diseases that are characterized by neuroinflammation and, by extension, microglial activation. Why these sex differences exist is not known but the panoply of differences extend to microglial number, genotype and phenotype. Significantly, several of these sex-related differences are also evident in health and change during life emphasizing the dynamic and plastic nature of microglia. This review will consider how age impacts on sex-related differences in microglia and ask whether the advancement of personalized medicine demands that a greater focus is placed on studying sex-related differences in microglia in Alzheimer's disease, Parkinson's disease and models of inflammatory stress and trauma in order to make true progress in dealing with these conditions.

Mechanistic Insight into Diosmin-Induced Neuroprotection and Memory Improvement in Intracerebroventricular-Quinolinic Acid Rat Model: Resurrection of Mitochondrial Functions and Antioxidants

Neurodegeneration is the final event after a cascade of pathogenic mechanisms in several brain disorders that lead to cognitive and neurological loss. Quinolinic acid (QA) is an excitotoxin derived from the tryptophan metabolism pathway and is implicated in several ailments, such as Alzheimer's, Parkinson's, Huntington's, and psychosis disease. Diosmin (DSM) is a natural flavonoid possessing such properties that may halt the course of neurodegenerative progression. In past studies, free radical scavenging, along with properties, such as antihyperglycemic, anti-inflammatory, and vasoactive properties, of DSM were pragmatic. Hence, in the current experimentations, the neuroprotective activity of DSM was investigated in the QA rat prototype. QA was administered through the intracerebroventricular route (QA-ICV) in rats on day one, and DSM (50 and 100 mg/kg, intraperitoneal route) was given from day 1 to 21. Memory, gait, sensorimotor functions, and biomarkers of oxidative mutilation and mitochondrial functions were evaluated in the whole brain. Results showed significant deterioration of sensorimotor performance, gait, and working- and long-term memory in rats by QA-ICV. These behavioral anomalies were significantly attenuated by DSM (50 and 100 mg/kg) and donepezil (standard drug). QA-ICV-induced decrease in body mass (g), diet, and water ingestion were also attenuated by DSM or donepezil treatments. QA-ICV inhibited mitochondrial complex I and II activities that caused an increase in oxidative and nitrosative stress along with a reduction in endogenous antioxidants in the brain. DSM dose-dependently ameliorated mitochondrial functions and decreased oxidative stress in QA-ICV-treated rats. DSM can be a possible alternative in treating neurodegenerative disorders with underlying mitochondrial dysfunction pathology.

The potential neuroprotective effect of diosmin in rotenone-induced model of Parkinson's disease in rats

Most treatments for Parkinson's disease (PD) focus on improving the symptoms and the dopaminergic effects; nevertheless, they cannot delay the disease progression. Diosmin (DM), a naturally occurring flavone that is obtained from citrus fruits, has demonstrated anti-apoptotic, anti-inflammatory and antioxidative properties in many diseases. This study aimed to assess the neuroprotective effects of diosmin in rotenone-induced rat model of PD and investigate its potential underlying mechanisms. A preliminary dose-response study was conducted where rats were treated with DM (50,100 and 200 mg/kg, p.o.) concomitantly with rotenone (2 mg/kg, s.c.) for 4 weeks. Catalepsy, motor impairment, spontaneous locomotion, body weight, histological examination and tyrosine hydroxylase (TH) immunoreactivity were evaluated in both the midbrains and striata of rats. Treatment with DM (200 mg/kg) showed the most promising outcome therefore, it was selected for further evaluation of α-synuclein, Bax, Bcl2, nuclear factor kappa B (NF-кB), nuclear factor erythroid 2- related factor 2 (Nrf2), and heme oxygenase-1 (HO-1), in addition to biochemical analysis of tumor necrosis factor-α (TNF-α). Results showed that DM (200 mg/kg, p.o.) prevented rotenone-induced motor impairment, weight reduction and histological damage. Furthermore, it significantly inhibited rotenone-induced decrease in TH expression. These results were correlated with reduction in α-synuclein immunoreactivity, together with improvement of Bax/Bcl2 ratio compared to rotenone group. DM also attenuated rotenone-induced increase in NF-кB expression as well as TNF- α levels. Moreover, DM inhibited rotenone-induced upregulation of Nrf2/HO-1 pathway. Thus, the current study suggests that DM might be a promising candidate for managing the neuropathological course of PD.

Activating AhR alleviates cognitive deficits of Alzheimer's disease model mice by upregulating endogenous Aβ catabolic enzyme Neprilysin

Rationale: Neprilysin (NEP) is a major endogenous catabolic enzyme of amyloid β (Aβ). Previous studies have suggested that increasing NEP expression in animal models of Alzheimer's disease had an ameliorative effect. However, the underlying signaling pathway that regulates NEP expression remains unclear. The aryl hydrocarbon receptor (AhR) is a ligand-activated cytoplasmic receptor and transcription factor. Recent studies have shown that AhR plays essential roles in the central nervous system (CNS), but its physiological and pathological roles in regulating NEP are not entirely known.

Methods: Western blotting, immunofluorescence, quantitative RT-PCR and enzyme activity assay were used to verify the effects of AhR agonists on NEP in a cell model (N2a) and a mouse model (APP/PS1). Luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were conducted to investigate the roles of AhR in regulating NEP transcription. Object recognition test and the Morris water maze task were performed to assess the cognitive capacity of the mice.

Results: Activating AhR by the endogenous ligand L-Kynurenine (L-KN) or FICZ, or by the exogenous ligand diosmin or indole-3-carbinol (I3C) significantly increases NEP expression and enzyme activity in N2a cells and APP/PS1 mice. We also found that AhR is a direct transcription factor of NEP. Diosmin treatment effectively ameliorated the cognitive disorder and memory deficit of APP/PS1 transgenic mice. By knocking down AhR or using a small molecular inhibitor targeting AhR or NEP, we found that diosmin enhanced Aβ degradation through activated AhR and increased NEP expression.

Conclusions: These results indicate a novel pathway for regulating NEP expression in neurons and that AhR may be a potential therapeutic target for the treatment of Alzheimer's disease.

The Protective Effect of Docosahexaenoic Acid on PC12 Cells in Oxidative Stress Induced by H2O2 through the TrkB-Erk1/2-CREB Pathway

Docosahexaenoic acid (DHA) has attracted plenty of interest in the prevention of neurodegenerative diseases. Although the beneficial effects of DHA on the central nervous system function are recognized, more information on the molecular mechanisms involved in its neuroprotective effects is required. The present study aimed to evaluate the effects of DHA on the function of mitochondria, neurite growth-related proteins signaling pathway, and neural signal transmission. In this study, PC12 cells were treated with H₂O₂ (400 μM) to establish an oxidative damage model. Results showed that DHA improved the viability and morphology of PC12 cells. DHA significantly increased the antioxidant capacity, mitochondrial membrane potential, and activity of ATPase in the cells. Furthermore, the phosphorylation levels of tyrosine kinase receptor (BTrkB), phospholipase C-γ1 (PLCγ1), calcium/calmodulin-dependent protein kinase II (CaMKII), extracellular regulated protein kinases 1/2 (ERK1/2), and cAMP-response element-binding protein (CREB) were upregulated by DHA. The damage on F-actin induced by H₂O₂ was reversed by DHA, indicating that DHA could protect neurite outgrowth. In addition, DHA increased the content of acetylcholine and γ-aminobutyric acid while decreasing glutamic acid. These results revealed that DHA could protect PC12 cells from damage induced by H₂O₂ through the TrkB-ERK1/2-CREB pathway.

Extensive metabolism of flavonoids relevant to their potential efficacy on Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disorder, the incidence of which is climbing with ever-growing aged population, but no cure is hitherto available. The epidemiological studies unveiled that chronic intake of flavonoids was negatively associated with AD risk. Flavonoids, a family of natural polyphenols widely distributed in human daily diets, were readily conjugated by phase II drug metabolizing enzymes after absorption in vivo, and glucuronidation could occur in 1 min following intravenous administration. Recently, as many as 191 metabolites were obtained after intragastric administration of a single flavonoid, indicating that other bioactive metabolites, besides conjugates, might be formed and account for the contradiction between efficacy of flavonoids in human or animal models and low systematic exposure of flavonoid glycosides or aglycones. In this review, metabolism of complete 68 flavonoid monomers potential for AD treatment, grouped in flavonoid O-glycosides, flavonoid aglycones, flavonoid C-glycosides, flavonoid dimers, flavonolignans and prenylated flavonoids according to their common structural elements, respectively, has been systematically retrospected, summarized and discussed, including their unequivocally identified metabolites, metabolic interconversions, metabolic locations, metabolic sites (regio- or stereo-selectivity), primarily involved metabolic enzymes or intestinal bacteria, and interspecies correlations or differences in metabolism, and their bioactive metabolites and the underlying mechanism to reverse AD pathology were also reviewed, providing whole perspective about advances on extensive metabolism of diverse potent flavonoids in vivo and in vitro up to date and aiming at elucidation of mechanism of actions of flavonoids on AD or other central nervous system (CNS) disorders.

Neuroprotective potential of Malva neglecta is mediated via down-regulation of cholinesterase and modulation of oxidative stress markers

Alzheimer's disease affects daily routine due to loss of memory and decline in cognition. In vitro data showed acetylcholine esterase inhibition activity of Malva neglecta but no in vivo evidence is available. The current study aims to investigate the anti-Alzheimer's activity of Malva neglecta methanolic extract in the AlCl₃-induced Alzheimer disease rats' model. Thirty Wistar rats were divided into six groups and respective doses were given orally for 21 days. Behavioural observations were recorded and biochemical analysis was performed on brain homogenate. Improvement in memory and cognition was noted in treated rats as compared to disease control. A dose-dependent decrease (0.530 ± 0.009 at 200 mg/kg, 0.212 ± 0.007 at 400 mg/kg, 0.173 ± 0.005 at 600 mg/kg) in AChE activity was noted in the treatment groups with reference to disease control value (1.572 ± 0.013). This decrease in AChE activity is linked with an increase in acetylcholine in the brain which plays a key role in retaining memory. Oxidative stress biomarkers; GSH (66.77 ± 0.01 at 600 mg/kg), SOD (26.60 ± 0.10 at 600 mg/kg), CAT (21.46 ± 0.01 at 600 mg/kg) levels were increased with a decrease in MDA (103.33 ±0.49 at 600 mg/kg) level in a dose-dependently manner in the treatment groups as compared to disease control respective values. It is concluded that Malva neglecta could ameliorate Alzheimer's symptoms possibly by decreasing AChE activity and oxidative stress.

Nutraceuticals-based therapeutic approach: recent advances to combat pathogenesis of Alzheimer's disease

Introduction: Alzheimer's disease (AD) is a progressive neurodegenerative disease accompanying memory deficits. The available pharmaceutical care has some limitations mostly entailing side effects, shelf-life, and patient's compliance. The momentous implications of nutraceuticals in AD have attracted scientists. Several preclinical studies for the investigation of nutraceuticals have been conducted.Areas covered: This review focuses on the potential use of a nutraceuticals-based therapeutic approach to treat and prevent AD. Increasing knowledge of AD pathogenesis has led to the discovery of new therapeutic targets including pathophysiological mechanisms and various cascades. Hence, the present contribution will attend to the most popular and effective nutraceuticals with proposed brief mechanisms entailing antioxidant, anti-inflammatory, autophagy regulation, mitochondrial homeostasis, and more. Therefore, even though the effectiveness of nutraceuticals cannot be dismissed, it is essential to do further high-quality randomized clinical trials.Expert opinion: According to the potential of nutraceuticals to combat AD as multi-target directed drugs, there is critical importance to assess them as feasible lead compounds for drug discovery and development. To the best of the authors' knowledge, modification of blood-brain barrier permeability, bioavailability, and features of randomized clinical trials should be considered in prospective studies.

The Roles of Flavonols/Flavonoids in Neurodegeneration and Neuroinflammation

The inflammatory process in the human body is a physiological response involving many cellular types and mediators. It results in scar formation to separate the damaged area from the surrounding healthy tissue. Because of increased blood-brain barrier permeability following inflammation, leukocytes infiltrate the CNS and are also supplemented by proinflammatory mediators. However, an acute inflammatory process after cerebral trauma or stroke may also result in a prolonged lesion formation, leading to a severe neuronal loss. The prolonged inflammatory process in the CNS may cause serious damage to the neuronal system. It may lead to CNS damage in such a way that endangers functional integration and proinflammatory system balance. Effects of different flavonoid species on ischemia-reperfusion injury and cognition and function have also been shown in experimental studies. Flavonoids are presented broadly in plants and diets. They are believed to have various bioactive effects including anti-viral, anti-inflammatory, cardioprotective, anti-diabetic, anti-cancer, anti-aging, etc. Quercetine is the predominant dietary flavonoid. Main sources are tea, onion, and apple. It is demonstrated that the frequently consumed food like soybean, peanut, mustard, rice, sesame, olive, potatoes, onion, and oats contain flavonoids. Catechin and its derivates which are isolated from tea leaves have antioxidant activity but in low doses, their prooxidant effects are also reported. Ipriflavone which is a synthetic flavonoid may increase total calcium in bone. In this review, the effects of flavonoids species on the inflammatory process in the neurodegenerative process were examined as general.

Disposable Pencil Graphite Electrode for Diosmin Voltammetric Analysis

Diosmin (DIO) is a naturally occurring flavonoid with multiple beneficial effects on human health. The presence of different hydroxyl groups in diosmin structure enables its electrochemical investigation and quantification. This work presents, for the first time, diosmin voltammetric behavior and quantification on the cost-effective, disposable pencil graphite electrode (PGE). Diosmin oxidation on PGE involves two irreversible steps, generating products with reversible redox behaviors. All electrode processes are pH-dependent and predominantly adsorption-controlled. Differential pulse (DPV) and adsorptive stripping differential pulse (AdSDPV) voltammetric methods have been optimized for diosmin quantification o an H-type PGE, in 0.100 mol/L H₂SO₄. The linear ranges and limits of detection were for DPV 1.00 × 10^-6-1.00 × 10^-5 mol/L and 2.76 × 10^-7 mol/L DIO for DPV and 1.00 × 10^-7-2.50 × 10^-6 mol/L and 7.42 × 10^-8 mol/L DIO for AdSDPV, respectively. The DPV method was successfully applied for diosmin quantification in dietary supplement tablets. The percentage recovery was 99.87 ± 4.88%.

Sexual Dimorphism in the 3xTg-AD Mouse Model and Its Impact on Pre-Clinical Research

Female sex is a leading risk factor for developing Alzheimer’s disease (AD). Sexual dimorphism in AD is gaining attention as clinical data show that women are not only more likely to develop AD but also to experience worse pathology and faster cognitive decline. Pre-clinical AD research in animal models often neglects to address sexual dimorphism in evaluation of behavioral or molecular characteristics and outcomes. This can compromise its translation to a clinical setting. The triple-transgenic AD mouse model (3xTg-AD) is a commonly used but unique AD model because it exhibits both amyloid and tau pathology, essential features of the human AD phenotype. Mounting evidence has revealed important sexually dimorphic characteristics of this animal model that have yet to be reviewed and thus, are often overlooked in studies using the 3xTg-AD model. In this review we conduct a thorough analysis of reports of sexual dimorphism in the 3xTg-AD model including findings of molecular, behavioral, and longevity-related sex differences in original research articles through August 2020. Importantly, we find results to be inconsistent, and that strain source and differing methodologies are major contributors to lack of consensus regarding traits of each sex. We first touch on the nature of sexual dimorphism in clinical AD, followed by a brief summary of sexual dimorphism in other major AD murine models before discussing the 3xTg-AD model in depth. We conclude by offering four suggestions to help unify pre-clinical mouse model AD research inspired by the NIH expectations for considering sex as a biological variable.

Flavonoid-Based Nanomedicines in Alzheimer's Disease Therapeutics: Promises Made, a Long Way To Go

Alzheimer's disease (AD) is characterized by the continuous decline of the cognitive abilities manifested due to the accumulation of large aggregates of amyloid-beta 42 (Aβ42), the formation of neurofibrillary tangles of hyper-phosphorylated forms of microtubule-associated tau protein, which may lead to many alterations at the cellular and systemic level. The current therapeutic strategies primarily focus on alleviating pathological symptoms rather than providing a possible cure. AD is one of the highly studied but least understood neurological problems and remains an unresolved condition of human brain degeneration. Over the years, multiple naturally derived small molecules, including plant products, microbial isolates, and some metabolic byproducts, have been projected as supplements reducing the risk or possible treatment of the disease. However, unfortunately, none has met the expected success. One major challenge for most medications is their ability to cross the blood-brain barrier (BBB). In past decades, nanotechnology-based interventions have offered an alternative platform to address the problem of the successful delivery of the drugs to the specific targets. Interestingly, the exciting interface of natural products and nanomedicine is delivering promising results in AD treatment. The potential applications of flavonoids, the plant-derived compounds best known for their antioxidant activities, and their amalgamation with nanomedicinal approaches may lead to highly effective therapeutic strategies for treating well-known neurodegenerative diseases. In the present review, we explore the possibilities and recent developments on an exciting combination of flavonoids and nanoparticles in AD.

Flavonoids as an Intervention for Alzheimer's Disease: Progress and Hurdles Towards Defining a Mechanism of Action

Attempts to develop a disease modifying intervention for Alzheimer’s disease (AD) through targeting amyloid β (Aβ) have so far been unsuccessful. There is, therefore, a need for novel therapeutics against alternative targets coupled with approaches which may be suitable for early and sustained use likely required for AD prevention. Numerous in vitro and in vivo studies have shown that flavonoids can act within processes and pathways relevant to AD, such as Aβ and tau pathology, increases in BDNF, inflammation, oxidative stress and neurogenesis. However, the therapeutic development of flavonoids has been hindered by an ongoing lack of clear mechanistic data that fully takes into consideration metabolism and bioavailability of flavonoids in vivo. With a focus on studies that incorporate these considerations into their experimental design, this review will evaluate the evidence for developing specific flavonoids as therapeutics for AD. Given the current lack of success of anti-Aβ targeting therapeutics, particular attention will be given to flavonoid-mediated regulation of tau phosphorylation and aggregation, where there is a comparable lack of study. Reflecting on this evidence, the obstacles that prevent therapeutic development of flavonoids will be examined. Finally, the significance of recent advances in flavonoid metabolomics, modifications and influence of the microbiome on the therapeutic capacity of flavonoids in AD are explored. By highlighting the potential of flavonoids to target multiple aspects of AD pathology, as well as considering the hurdles, this review aims to promote the efficient and effective identification of flavonoid-based approaches that have potential as therapeutic interventions for AD.

Diosmetin Mitigates Cognitive and Memory Impairment Provoked by Chronic Unpredictable Mild Stress in Mice

Materials and Methods

In the present experimental study, male NMRI mice were exposed to chronic unpredictable mild stress (CUMS) paradigm for 35 days. Diosmetin (at doses of 10, 20, and 40 mg/kg. i.p.) or diosmetin solvent (normal saline + DMSO, 1 ml/kg; i.p.) was administered 30 min before stress induction. After 28 days, memory and cognitive performance were assessed by shuttle box and novel object recognition tests. Finally, antioxidant capacity (FRAP) and malondialdehyde (MDA) level of serum and brain, and serum corticosterone level were evaluated.

Results

Behavioral tests showed that CUMS significantly reduced the secondary latency in passive avoidance memory test and diagnosis index in novel object recognition test compared to the control group (P < 0.001), whereas treatment with diosmetin (20 and 40 mg/kg) significantly improved memory performance in the two tests (P < 0.001). In addition, diosmetin (40 mg/kg) could pronouncedly suppress increase in serum corticosterone levels, reduction in antioxidant capacity, and production of excess MDA caused by CUMS compared to the control group (P < 0.01, P < 0.001, and P < 0.001, respectively).

Conclusion

Chronic stress can impair memory and cognition and treatment with diosmetin can partly improve this disorder in male mice by increasing the antioxidant capacity of brain tissue and serum and improving serum corticosterone levels.

Electroacupuncture reduces scopolamine-induced amnesia via mediating the miR-210/SIN3A and miR-183/SIN3A signaling pathway

Background

The expression of SIN3A is closely correlated with electroacupuncture (EA) treatment efficacy of scopolamine-induced amnesia (SIA), but its underlying mechanisms remain to be further explored.

Methods

Quantitative real-time PCR was performed to analyze the expression of candidate microRNAs (miRNAs) and SIN3A mRNA in a rat model of SIA. Western blot was carried out to evaluate the differential expression of SIN3A proteins under different circumstances. Luciferase assay was used to explore the inhibitory role of certain miRNAs in SIN3A expression. A novel object recognition (NOR) test was performed to assess the memory function of SIA rats undergoing EA treatment. Immunohistochemistry was carried out to evaluate the expression of SIN3A in the hippocampus of SIA rats.

Results

Rno-miR-183-5p, rno-miR-34c-3p and rno-miR-210-3p were significantly up-regulated in SIA rats treated with EA. In addition, rno-miR-183-5p and rno-miR-210-3p exerted an inhibitory effect on SIN3A expression. EA treatment of SIA rats effectively restored the dysregulated expression of rno-miR-183-5p, rno-miR-210-3p and SIN3A. EA treatment also promoted the inhibited expression of neuronal IEGs including Arc, Egr1, Homer1 and Narp in the hippocampus of SIA rats. Accordingly, the NOR test also confirmed the effect of EA treatment on the improvement of memory in SIA rats.

Conclusion

In summary, the findings of this study demonstrated that scopolamine-induced amnesia was associated with downregulated expression of miR-210/miR-183 and upregulated expression of SIN3A. Furthermore, treatment with EA alleviated scopolamine-induced amnesia in rats and was associated with upregulated expression of miR-210/miR-183 and downregulated expression of SIN3A.

Diosmin attenuates schizophrenia-like behavior, oxidative stress, and acetylcholinesterase activity in mice

OBJECTIVES

Diosmin (DSM), commonly isolated from various plants, is a citrus nutrient that has been shown to increase intracellular antioxidant capacity and assuage symptoms associated with neurological disorders. Deficiency in the antioxidant system has been implicated in the pathogenesis of schizophrenia. The use of antioxidants as neuroprotectants to suppress schizophrenia pathology is increasingly being sought. Hence, this study investigated the effects of DSM on schizophrenia-like behavior and the underlying changes in biomarkers of oxidative stress and acetylcholinesterase (AChE) activity in mice.

METHODS

The acute antipsychotic effect of DSM (25, 50, and 100 mg/kg, intraperitoneally [i.p.]), haloperidol (1 mg/kg, i.p.), and risperidone (RIS) (0.5 mg/kg, i.p.) was investigated on stereotyped behaviors induced by apomorphine (2 mg/kg, i.p.) and ketamine (10 mg/kg, i.p.). The effect of DSM on ketamine-induced hyperlocomotion, immobility enhancement, and its woodblock cataleptogenic potential was evaluated. Also, the subacute antipsychotic potential of DSM was assessed following intraperitoneal injection of DSM (25-100 mg/kg, i.p.) alone and in combination with ketamine (20 mg/kg, i.p.) for 10 days. The behaviors of the animals were assessed in the open-field, Y-maze, and forced swim tests. Brains of the animals were afterward processed for spectrophotometric assay of oxidative stress and AChE contents.

RESULTS

DSM (25, 50, and 100 mg/kg) attenuated apormorphine-induced stereotypy and devoid of cataleptogenic effect. DSM and RIS reversed acute and subacute ketamine-induced schizophrenia-like behaviors. Disomin alone increased cognitive function and reduced despair-like phenotype. Furthermore, DSM increased superoxide dismutase and glutathione and decreased malondialdehyde and AChE levels in naïve and ketamine schizophrenic mice.

CONCLUSIONS

DSM prevents schizophrenia-like behavior, attenuates oxidative stress, and AChE activity in naïve and ketamine schizophrenic mice.

Diosmin attenuates schizophrenia-like behavior, oxidative stress, and acetylcholinesterase activity in mice

Objectives Diosmin (DSM), commonly isolated from various plants, is a citrus nutrient that has been shown to increase intracellular antioxidant capacity and assuage symptoms associated with neurological disorders. Deficiency in the antioxidant system has been implicated in the pathogenesis of schizophrenia. The use of antioxidants as neuroprotectants to suppress schizophrenia pathology is increasingly being sought. Hence, this study investigated the effects of DSM on schizophrenia-like behavior and the underlying changes in biomarkers of oxidative stress and acetylcholinesterase (AChE) activity in mice. Methods The acute antipsychotic effect of DSM (25, 50, and 100 mg/kg, intraperitoneally [i.p.]), haloperidol (1 mg/kg, i.p.), and risperidone (RIS) (0.5 mg/kg, i.p.) was investigated on stereotyped behaviors induced by apomorphine (2 mg/kg, i.p.) and ketamine (10 mg/kg, i.p.). The effect of DSM on ketamine-induced hyperlocomotion, immobility enhancement, and its woodblock cataleptogenic potential was evaluated. Also, the subacute antipsychotic potential of DSM was assessed following intraperitoneal injection of DSM (25-100 mg/kg, i.p.) alone and in combination with ketamine (20 mg/kg, i.p.) for 10 days. The behaviors of the animals were assessed in the open-field, Y-maze, and forced swim tests. Brains of the animals were afterward processed for spectrophotometric assay of oxidative stress and AChE contents. Results DSM (25, 50, and 100 mg/kg) attenuated apormorphine-induced stereotypy and devoid of cataleptogenic effect. DSM and RIS reversed acute and subacute ketamine-induced schizophrenia-like behaviors. Disomin alone increased cognitive function and reduced despair-like phenotype. Furthermore, DSM increased superoxide dismutase and glutathione and decreased malondialdehyde and AChE levels in naïve and ketamine schizophrenic mice. Conclusions DSM prevents schizophrenia-like behavior, attenuates oxidative stress, and AChE activity in naïve and ketamine schizophrenic mice.

Molecular Insight into the Therapeutic Promise of Flavonoids against Alzheimer's Disease

Alzheimer’s disease (AD) is one of the utmost chronic neurodegenerative disorders, which is characterized from a neuropathological point of view by the aggregates of amyloid beta (Aβ) peptides that are deposited as senile plaques and tau proteins which form neurofibrillary tangles (NFTs). Even though advancement has been observed in order to understand AD pathogenesis, currently available therapeutic methods can only deliver modest symptomatic relief. Interestingly, naturally occurring dietary flavonoids have gained substantial attention due to their antioxidative, anti-inflammatory, and anti-amyloidogenic properties as alternative candidates for AD therapy. Experimental proof provides support to the idea that some flavonoids might protect AD by interfering with the production and aggregation of Aβ peptides and/or decreasing the aggregation of tau. Flavonoids have the ability to promote clearance of Aβ peptides and inhibit tau phosphorylation by the mTOR/autophagy signaling pathway. Moreover, due to their cholinesterase inhibitory potential, flavonoids can represent promising symptomatic anti-Alzheimer agents. Several processes have been suggested for the aptitude of flavonoids to slow down the advancement or to avert the onset of Alzheimer’s pathogenesis. To enhance cognitive performance and to prevent the onset and progress of AD, the interaction of flavonoids with various signaling pathways is proposed to exert their therapeutic potential. Therefore, this review elaborates on the probable therapeutic approaches of flavonoids aimed at averting or slowing the progression of the AD pathogenesis.

Metabolism and pharmacological activities of the natural health-benefiting compound diosmin

Diosmin is a famous natural flavonoid for treating chronic venous insufficiency and varicose veins.

A Novel Apolipoprotein E Antagonist Functionally Blocks Apolipoprotein E Interaction With N-terminal Amyloid Precursor Protein, Reduces β-Amyloid-Associated Pathology, and Improves Cognition

BACKGROUND

The ɛ4 isoform of apolipoprotein E (apoE4) is a major genetic risk factor for the development of sporadic Alzheimer's disease (AD), and its modification has been an intense focus for treatment of AD during recent years.

METHODS

We investigated the binding of apoE, a peptide corresponding to its low-density lipoprotein receptor binding domain (amino acids 133-152; ApoEp), and modified ApoEp to amyloid precursor protein (APP) and their effects on amyloid-β (Aβ) production in cultured cells. Having discovered a peptide (6KApoEp) that blocks the interaction of apoE with N-terminal APP, we investigated the effects of this peptide and ApoEp on AD-like pathology and behavioral impairment in 3XTg-AD and 5XFAD transgenic mice.

RESULTS

ApoE and ApoEp, but not truncated apoE lacking the low-density lipoprotein receptor binding domain, physically interacted with N-terminal APP and thereby mediated Aβ production. Interestingly, the addition of 6 lysine residues to the N-terminus of ApoEp (6KApoEp) directly inhibited apoE binding to N-terminal APP and markedly limited apoE- and ApoEp-mediated Aβ generation, presumably through decreasing APP cellular membrane trafficking and p44/42 mitogen-activated protein kinase phosphorylation. Moreover, while promoting apoE interaction with APP by ApoEp exacerbated Aβ and tau brain pathologies in 3XTg-AD mice, disrupting this interaction by 6KApoEp ameliorated cerebral Aβ and tau pathologies, neuronal apoptosis, synaptic loss, and hippocampal-dependent learning and memory impairment in 5XFAD mice without altering cholesterol, low-density lipoprotein receptor, and apoE expression levels.

CONCLUSIONS

These data suggest that disrupting apoE interaction with N-terminal APP may be a novel disease-modifying therapeutic strategy for AD.

Early Intervention with a Multi-Ingredient Dietary Supplement Improves Mood and Spatial Memory in a Triple Transgenic Mouse Model of Alzheimer's Disease

The increasing global burden of Alzheimer's disease (AD) and failure of conventional treatments to stop neurodegeneration necessitates an alternative approach. Evidence of inflammation, mitochondrial dysfunction, and oxidative stress prior to the accumulation of amyloid-β in the prodromal stage of AD (mild cognitive impairment; MCI) suggests that early interventions which counteract these features, such as dietary supplements, may ameliorate the onset of MCI-like behavioral symptoms. We administered a polyphenol-containing multiple ingredient dietary supplement (MDS), or vehicle, to both sexes of triple transgenic (3xTg-AD) mice and wildtype mice for 2 months from 2-4 months of age. We hypothesized that the MDS would preserve spatial learning, which is known to be impaired in untreated 3xTg-AD mice by 4 months of age. Behavioral phenotyping of animals was done at 1-2 and 3-4 months of age using a comprehensive battery of tests. As previously reported in males, both sexes of 3xTg-AD mice exhibited increased anxiety-like behavior at 1-2 months of age, prior to deficits in learning and memory, which did not appear until 3-4 months of age. The MDS did not reduce this anxiety or prevent impairments in novel object recognition (both sexes) or on the water maze probe trial (females only). Strikingly, the MDS specifically prevented 3xTg-AD mice (both sexes) from developing impairments (exhibited by untreated 3xTg-AD controls) in working memory and spatial learning. The MDS also increased sucrose preference, an indicator of hedonic tone. These data show that the MDS can prevent some, but not all, psychopathology in an AD model.

Expression Profiles of Long Noncoding RNAs in Intranasal LPS-Mediated Alzheimer's Disease Model in Mice

Alzheimer's disease (AD), characterized by memory loss, cognitive decline, and dementia, is a progressive neurodegenerative disease. Although the long noncoding RNAs (lncRNAs) have recently been identified to play a role in the pathogenesis of AD, the specific effects of lncRNAs in AD remain unclear. In present study, we have investigated the expression profiles of lncRNAs in hippocampal of intranasal LPS-mediated Alzheimer's disease models in mice by microarray method. A total of 395 lncRNAs and 123 mRNAs was detected to express differently in AD models and controls (>2.0 folds, p<0.05). The microarray expression was validated by Quantitative Real-Time-PCR (qRT-PCR). The pathway analysis showed the mRNAs that correlated with lncRNAs were involved in inflammation, apoptosis, and nervous system related pathways. The lncRNA-TFs network analysis suggested the lncRNAs were mostly regulated by HMGA2, ONECUT2, FOXO1, and CDC5L. Additionally, lncRNA-target-TFs network analysis indicated the FOXL1, CDC5L, ONECUT2, and CDX1 to be the TFs most likely to regulate the production of these lncRNAs. This is the first study to investigate lncRNAs expression pattern in intranasal LPS-mediated Alzheimer's disease model in mice. And these results may facilitate the understanding of the pathogenesis of AD targeting lncRNAs.

Diosmetin as a novel transient receptor potential vanilloid 1 antagonist with antinociceptive activity in mice

Diosmetin is an O‑methylated flavone found naturally in citrus fruit, and it was identified in Amphilophium crucigerum (L.), a plant popularly used as an analgesic. This compound had different pharmacological effects and presented a chemical structure like the flavonoid eriodyctiol that exhibited antinociceptive effects by TRPV1 antagonism. However, the possible antinociceptive effect of this compound was not well documented. Thus, the goal of the present study was to evaluate the antinociceptive effect of diosmetin and its mechanism of action. The diosmetin effect on different pain models and its possible adverse effects were assessed on adult Swiss male mice (25-30 g). Mice spinal cord samples were used on calcium influx and binding assays using TRPV1 agonists. First, it was observed that the diosmetin reduced calcium influx mediated by capsaicin in synaptosomes and displace the specific binding to [³H]-resiniferatoxin in membrane fractions from the spinal cord of mice. Diosmetin (0.15 to 1.5 mg/kg, intragastric, i.g.) presented antinociceptive and antiedematogenic effect in the capsaicin intraplantar test and induced antinociception in a noxious heat test (48 °C). Also, treatment with diosmetin reduced mechanical and heat hypersensitivity observed in a model of inflammatory or neuropathic pain. Acute diosmetin administration in mice did not induce locomotor or body temperature changes, or cause liver enzyme abnormalities or alter renal function. Moreover, there were no observed changes in gastrointestinal transit or induction of ulcerogenic activity after diosmetin administration. In conclusion, our results support the antinociceptive properties of diosmetin which seems to occur via TRPV1 antagonist in mice.

A novel view on Alzheimer’s disease pathogenesis: modern conceptof amyloid clearance

Alzheimer’s disease is the most common cause of dementia among the elderly. Te pathological changes characterize by the deposition of amyloid plaques and the formation of neurofybrillar tangles in the brain. Te most signifcant role in the pathogenesis of neurodegeneration development is deposition of β-amyloid, vascular risk factors, the presence of a genetic predisposition, and the dysregulation of the bloodbrain barrier. Recent studies have demonstrated the role of the glymphatic system in the clearance of betaamyloid through the perivascular spaces of Virchow-Robin.

Anti-neuroinflammatory effects of SLOH in Aβ-induced BV-2 microglial cells and 3xTg-AD mice involve the inhibition of GSK-3β

Neuroinflammation has been observed in post-mortem Alzheimer's disease (AD) brains which could be due to Aβ interacting with microglia and astrocytes. SLOH, a carbazole-based fluorophore, was shown to bind to Aβ peptides. Herein, we investigated the anti-neuroinflammatory effects of SLOH using a BV-2 microglial cell model and a triple transgenic AD (3xTg-AD) mouse model. BV-2 cells were incubated with Aβ in the presence of SLOH for 24 h. The levels of pro-inflammatory and anti-inflammatory cytokines were determined. Moreover, 3xTg-AD mice were administrated with SLOH (2 mg kg^-1) for one month. The mice were then sacrificed and the brains were used to assess the levels of pro-inflammatory, anti-inflammatory cytokines and the activation of ionized calcium-binding adapter molecule 1 (Iba1). BV-2 cell studies suggested that SLOH reduced the production and mRNA levels of pro-inflammatory cytokines TNF-α, IL-1β, COX-2, iNOS, and increased IL-10. Animal study confirmed that SLOH reduced the production of pro-inflammatory cytokines and increased the level of anti-inflammatory cytokine. Moreover, SLOH inhibited the activity of GSK-3β. In 3xTg-AD mouse model, SLOH treatment significantly decreased the number of Iba1-positive cells in mouse brains. Our results demonstrated that SLOH significantly attenuated the neuroinflammation through down-regulating the activity of GSK-3β.

Human Umbilical Cord Blood Serum-derived α-Secretase: Functional Testing in Alzheimer's Disease Mouse Models

Alzheimer’s disease (AD) is an age-related disorder that affects cognition. Our previous studies showed that the neuroprotective fragment of amyloid procurer protein (APP) metabolite, soluble APPα (sAPPα), interferes with β-site APP-cleaving enzyme 1 (BACE1, β-secretase) cleavage and reduces amyloid-β (Aβ) generation. In an attempt to identify approaches to restore sAPPα levels, we found that human cord blood serum (CBS) significantly promotes sAPPα production compared with adult blood serum (ABS) and aged blood serum (AgBS) in Chinese hamster ovary cells stably expressing wild-type human APP. Interestingly, CBS selectively mediated the α-secretase cleavage of human neuron-specific recombinant APP₆₉₅ in a cell-free system independent of tumor necrosis factor-α converting enzyme (TACE; a disintegrin and metalloproteinase domain-containing protein 17 [ADAM17]) and ADAM. Subsequently, using 3-step chromatographic separation techniques (i.e., diethylaminoethanol, size-exclusion, and ion-exchange chromatography), we purified and ultimately identified a CBS-specific fraction with enhanced α-secretase catalytic activity (termed αCBSF) and found that αCBSF has more than 3,000-fold increased α-secretase catalytic activity compared with the original pooled CBS. Furthermore, intracerebroventricular injection of αCBSF markedly increased cerebral sAPPα levels together with significant decreases in cerebral Aβ production and abnormal tau (Thr²³¹) phosphorylation compared with the AgBS fraction with enhanced α-secretase activity (AgBSF) treatment in triple transgenic Alzheimer’s disease (3xTg-AD) mice. Moreover, AgBSF administered intraperitoneally to transgenic mice with five familial Alzheimer’s disease mutations (5XFAD) via an osmotic mini pump for 6 weeks (wk) ameliorated β-amyloid plaques and reversed cognitive impairment measures. Together, our results propose the necessity for further study aimed at identification and characterization of α-secretase in CBS for novel and effective AD therapy.

LED enhances anti-inflammatory effect of luteolin (3',4',5,7-tetrahydroxyflavone) in vitro

Neuroinflammation is a complex pathological process usually results from abnormal microglial activation, thus, intervention in a microglial stimulation pathway could be a promising approach for the treatment of neurodegenerative diseases. Luteolin is an important bioflavonoid possesses anti-inflammatory properties, which is widely studied over these years. Light emitting diode (LED) therapy is reported to be a potential therapeutic strategy for many diseases including neurodegenerative diseases. However, little is known about the anti-inflammatory effect of LED therapy on activated microglial cells, even less is known whether there is a synergistic anti-inflammatory effect exist in LED and luteolin therapy. In this study, we aimed to confirm the anti-inflammatory effect of luteolin and LED combination therapy in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. We showed that luteolin inhibited LPS-induced cytotoxicity, tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) production through modulation of p38 and extracellular signal-regulated kinase (ERK) signaling in BV2 cells. In addition, LED therapy enhanced the anti-inflammatory effect of luteolin. These results suggest that a synergistic effect between luteolin and LED could be a new effective therapy in relieving neuroinflammation.