The influence of quercetin on recognition memory and brain oxidative damage in a ketamine model of schizophrenia

The comparison of the antidiabetic effects of exenatide, empagliflozin, quercetin, and combination of the drugs in type 2 diabetic rats

BACKGROUND

Type 2 diabetes, a metabolic disease that involves extended treatment, is rapidly increasing in humans and animals worldwide.

OBJECTIVES

This study aimed to compare monotherapy and combined therapy of exenatide, empagliflozin, and quercetin in 67 Wistar Albino male rats.

METHODS

The animals were divided into the following seven groups: healthy control, diabetes control, diabetes + sham, diabetes + exenatide (10 μg/kg), diabetes + empagliflozin (50 mg/kg), diabetes + quercetin (50 mg/kg), and diabetes + combination treatment. The treatments were continued for 8 weeks.

RESULTS

At the end of the experiment, glucose and HbA1c levels decreased with all monotherapy treatments and the combination treatments, while insulin levels increased with exenatide and combined treatments. Adiponectin levels increased with empagliflozin, quercetin, and combined treatments, while leptin levels decreased only with combined treatments. All monotherapies caused an increase in total antioxidant levels. Exenatide and quercetin treatments reduced low-density lipoprotein (LDL) levels; therewithal, exenatide and combined treatments increased high-density lipoprotein (HDL) levels. Triglyceride levels decreased in all treatment groups. The homeostatic model assessment for insulin resistance (HOMA-IR) level decreased with the combined treatment; on the contrary, the homeostatic model assessment for β-cell activity (HOMA-β) level increased with empagliflozin, exenatide, and combined treatments.

CONCLUSION

In conclusion, the antidiabetic effects of exenatide were more pronounced than empagliflozin and quercetin, however, the combined treatment had better antidiabetic and antihyperlipidemic effects than monotherapies. Quercetin could be a supportive or food supplement antidiabetic agent. The exenatide treatment can be recommended for monotherapy in type 2 patients, and the combination of empagliflozin, exenatide, and quercetin may be effective in diabetic patients who need combined therapy.

Quercetin's Restorative Properties in Male Mice with 3-Nitropropionic Acid-induced Huntington-like Symptoms: Molecular Docking, Behavioral, and Biochemical Assessment

The neurotoxicity of 3-Nitropropionic acid (3-NP) is well known. Herein, the prophylactic versus therapeutic effects of quercetin (QCT) were investigated against 3-NP-induced behavioral anomalies and oxidative neural damage. Thirty male mice were assigned into five groups; the negative control group, the QCT group (25 mg/kg/day, p.o. for 21 days), the 3-NP group (17 days), the prophylactic group (QCT administration for 14 consecutive days, and then 3-NP was administrated), the therapeutic group (3-NP was administrated and then QCT for 21 days). At the end of the animal treatment, behavioral studies were assessed. Subsequently, the brain sample tissues were assessed for oxidative stress-related parameters and histological evaluation. Moreover, the potential interaction between 3-NP and tumor necrosis factor-alpha (TNF-α) was evaluated by using a molecular docking study. 3-NP markedly led to neurotoxicity which was indicated by behavioral deficits (motor behavior, depression-like behavior, memory dysfunction, and passive avoidance) and oxidative damage. Blind and targeted molecular docking results showed good interaction between 3-NP and TNF-α. However, the prophylactic effects of QCT were superior to the therapeutic effects for attenuating 3-NP-induced neurobehavioral and oxidative neural changes in experimental mice, which histological changes of the brain's striatum region approved our findings. Taken together, the antioxidant activity of QCT remarkably could attenuate 3-NP-induced neurobehavioral deficits and mitochondrial dysfunctions in mice.

Honey on brain health: A promising brain booster

Since ancient times, honey has been employed in many aspects of everyday life, the most popular of which is as a natural sweetener. Honey is used not only as a nutritional product but also in health as a supplement and in various applications, especially related to brain booster health. Brain health is the capacity to carry out all mental functions necessary for cognition, such as learning and judging, utilizing language, and recalling. This review presents the current trend of research on honey, particularly the interest in underlying mechanisms related to brain booster health. A total of 34 original articles addressing brain health from the consumption of honey were analyzed. We identified four main brain health benefits, which are memory booster, neuroprotective effect, anti-stress, and anti-nociceptive potentials with the proposed underlying mechanism. A lot of attention has been paid to the role that honey plays in brain health research, with the goal of examining the link between honey and brain health as well as the mechanism underlying it, the findings from this review may be potentially beneficial to develop new therapeutic roles for honey to help determine the best and most promising to benefit and boost overall brain health.

Quercetin Is An Active Agent in Berries against Neurodegenerative Diseases Progression through Modulation of Nrf2/HO1

Berries are well-known fruits for their antioxidant effects due to their high content of flavonoids, and quercetin is one of the potent bioactive flavonoids. Although oxidative stress is an inevitable outcome in cells due to energy uptake and metabolism and other factors, excessive oxidative stress is considered a pivotal mediator for the cell death and leads to the progression of neurodegenerative diseases (NDDs). Furthermore, oxidative stress triggers inflammation that leads to neuronal cell loss. Alzheimer's, Parkinson's, Huntington's disease, amyotrophic lateral sclerosis, multiple sclerosis, and so on are the main neurodegenerative diseases. Hence, AD and PD are the most affected NDDs and cause the most lethality without any effective cure. Since AD and PD are the most common NDDs, therefore, in this study, we will describe the effect of oxidative stress on AD and PD. Targeting oxidative stress could be a very effective way to prevent and cure NDDs. Thus, the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO1) are potent endogenous antioxidant modulatory pathways, which also show cytoprotective activities. Modulation of Nrf2/HO1 signaling pathways through a biological approach could be an effective way to treat with NDDs. Quercetin is a natural polyphenol, which protects neurodegeneration, remarkably by suppressing oxidative stress and inflammation. Thus, quercetin could be a very effective agent against NDDs. We will discuss the benefits and challenges of quercetin to treat against NDDs, focusing on molecular biology.

Reversal of oxidative stress, cytokine toxicity and DNA fragmentation by quercetin in dizocilpine-induced animal model of Schizophrenia

Quercetin, a polyphenolic compound found in a variety of plant products possesses various biological activities and beneficial effects on human health. Schizophrenia (SZ) is one of the neuropsychiatric disorders in human beings with rapid mortality and intense morbidity which can be treated with antipsychotics, but these commercial drugs exert adverse effects and have less efficacy to treat the full spectrum of SZ. The present study was conducted to evaluate neuroprotective effects of quercetin in the preventive and therapeutic treatment of SZ. Quercetin was administered as pre- and post-regimens at the dose of 50 mg/kg in dizocilpine-induced SZ rat model for two weeks. Rats were then subjected for the assessment of different behaviors followed by biochemical, neurochemical, and inflammatory marker analyses. The present findings revealed that quercetin significantly reverses the effects of dizocilpine-induced psychosis-like symptoms in all behavioral assessments as well as it also combats oxidative stress. This flavonoid also regulates dopaminergic, serotonergic, and glutamatergic neurotransmission. A profound effect on inflammatory cytokines and decreased %DNA fragmentation was also observed following the administration of quercetin. The findings suggest that quercetin can be considered as a preventive as well as therapeutic strategy to attenuate oxidative stress and cytokine toxicity, regulate neurotransmission, and prevent enhanced DNA fragmentation that can lead to the amelioration of psychosis-like symptoms in SZ.

Biochemical profiling of metabolomics in heavy metal-intoxicated impaired metabolism and its amelioration using plant-based bioactive compound

Exposure to Pb is widely spreading and has far-reaching negative effects on living systems. This study aimed to investigate the toxic effects of Pb, through biochemical profiling and the ameliorative effects of quercetin against Pb-toxicity. Twenty-five male Wistar albino mice were divided into the following five groups. The CON-group received normal saline; the Pb-group received PbAc; the Pb + Q-CRN group received lead acetate followed by quercetin; the Q-CRN group received quercetin; and the CRN group received corn oil. After 4 weeks, the mice were euthanized. It was speculated that Pb significantly increased the levels of serine, threonine, and asparagine and decreased the levels of valine, lysine, and glutamic acid in the plasma of Pb-group, thus impairing amino acid metabolism. However, in the Pb + Q-CRN group, the level of these six amino acids was restored significantly due to the ameliorative effect of quercetin. The presence of lipid metabolites (L-carnitine, sphinganine, phytosphingosine, and lysophosphatidylcholine) in mice serum was confirmed by ESI/MS. The GPx, SOD, GSH, and CAT levels were significantly decreased, and the MDA level was significantly increased, thus confirming the oxidative stress and lipid peroxidation in the Pb group. The antioxidant effect of quercetin was elucidated in the Pb + Q-CRN group. Expression of CPT-I, CPT-II, LCAT, CROT, CACT, and MTR genes was significantly upregulated in the liver of Pb goup mice. Hence, the findings of this study proved that Pb exposure induced oxidative stress, upregulated gene expression, and impaired the lipid and amino acid metabolism in mice.

Neuroprotective effect of quercetin against rotenone-induced neuroinflammation and alterations in mice behavior

Various studies suggested that neuroinflammation leads to the development of several neurodegenerative disorders like Parkinson's disease (PD), Alzheimer's disease (AD), and Huntington's disease (HD). Rotenone is an organic pesticide and potent inhibitor of complex I of electron transport chain widely used to develop the PD model. Numerous studies reported rotenone toxicity in the dopaminergic system but very few studies are available on rotenone-induced glial cell activation and subsequent neurodegeneration and alterations in various types of behavior. Therefore, the present study was designed to explore the effect of rotenone on neuroinflammation and its deleterious effect on the behavior of mice, and also how these effects can be protected through quercetin. Quercetin, a natural flavonoid having strong antioxidant and anti-inflammatory properties, is found in vegetables and fruits. The finding of the study indicated that rotenone 5 mg/kg body weight for 60 days through oral gavage leads to the release of inflammatory markers in blood serum, astrocytes activation in substantia nigra and hippocampus, and subsequently decreased density of dopaminergic fibers in the striatum. Rotenone also altered the memory of the mice as indicated by decreased spontaneous alteration in Y-maze and T-maze tests and reduction in exploration time in novel object recognition, increased immobility time in the forced swim test and reduced muscular strength. Co-treatment of quercetin 30 mg/kg/day through oral gavage for 60 days along with rotenone significantly reversed all these adverse effects, suggesting that quercetin could reduce neuroinflammation, and improve memory, and cognitive function.

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.

Alternative Therapy of Psychosis: Potential Phytochemicals and Drug Targets in the Management of Schizophrenia

Schizophrenia is a chronic mental and behavioral disorder characterized by clusters of symptoms including hallucinations, delusions, disorganized thoughts and social withdrawal. It is mainly contributed by defects in dopamine, glutamate, cholinergic and serotonergic pathways, genetic and environmental factors, prenatal infections, oxidative stress, immune system activation and inflammation. Management of schizophrenia is usually carried out with typical and atypical antipsychotics, but it yields modest benefits with a diversity of side effects. Therefore, the current study was designed to determine the phytochemicals as new drug candidates for treatment and management of schizophrenia. These phytochemicals alter and affect neurotransmission, cell signaling pathways, endocannabinoid receptors, neuro-inflammation, activation of immune system and status of oxidative stress. Phytochemicals exhibiting anti-schizophrenic activity are mostly flavonoids, polyphenols, alkaloids, terpenoids, terpenes, polypropanoids, lactones and glycosides. However, well-designed clinical trials are consequently required to investigate potential protective effect and therapeutic benefits of these phytochemicals against schizophrenia.

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.

Is There a Glutathione Centered Redox Dysregulation Subtype of Schizophrenia?

Schizophrenia continues to be an illness with poor outcome. Most mechanistic changes occur many years before the first episode of schizophrenia; these are not reversible after the illness onset. A developmental mechanism that is still modifiable in adult life may center on intracortical glutathione (GSH). A large body of pre-clinical data has suggested the possibility of notable GSH-deficit in a subgroup of patients with schizophrenia. Nevertheless, studies of intracortical GSH are not conclusive in this regard. In this review, we highlight the recent ultra-high field magnetic resonance spectroscopic studies linking GSH to critical outcome measures across various stages of schizophrenia. We discuss the methodological steps required to conclusively establish or refute the persistence of GSH-deficit subtype and clarify the role of the central antioxidant system in disrupting the brain structure and connectivity in the early stages of schizophrenia. We propose in-vivo GSH quantification for patient selection in forthcoming antioxidant trials in psychosis. This review offers directions for a promising non-dopaminergic early intervention approach in schizophrenia.

Repurposing of Anti-Diabetic Agents as a New Opportunity to Alleviate Cognitive Impairment in Neurodegenerative and Neuropsychiatric Disorders

Cognitive impairment is a shared abnormality between type 2 diabetes mellitus (T2DM) and many neurodegenerative and neuropsychiatric disorders, such as Alzheimer’s disease (AD) and schizophrenia. Emerging evidence suggests that brain insulin resistance plays a significant role in cognitive deficits, which provides the possibility of anti-diabetic agents repositioning to alleviate cognitive deficits. Both preclinical and clinical studies have evaluated the potential cognitive enhancement effects of anti-diabetic agents targeting the insulin pathway. Repurposing of anti-diabetic agents is considered to be promising for cognitive deficits prevention or control in these neurodegenerative and neuropsychiatric disorders. This article reviewed the possible relationship between brain insulin resistance and cognitive deficits. In addition, promising therapeutic interventions, especially current advances in anti-diabetic agents targeting the insulin pathway to alleviate cognitive impairment in AD and schizophrenia were also summarized.

Encapsulation of tartary buckwheat flavonoids and application to yoghurt

Aims: The present work investigates the effect of tartary buckwheat flavonoid (TBF) capsules on the physical and chemical properties of yoghurt using polymeric whey protein (PWP) as a wall material.Methods: PWP was prepared by thermal polymerisation. TBF was encapsulated using PWP as the wall material via the pore-coagulation bath method. The physicochemical properties of the TBF capsules, such as the entrapment yield, moisture, average particle size, particle size distribution, surface morphology, molecular interactions, and thermal stability were investigated, in addition to the release of TBF in simulated gastric and intestinal juices. Yoghurt formulation was carried out using encapsulated TBF (3%, w/w), blank PWP beads (2.7%, w/w), and unencapsulated TBF (0.3%, w/w). A control yoghurt sample was prepared without these ingredients. The effects of encapsulated TBF on the chemical composition, acidity, texture, synaeresis, sensory properties, number of Streptococcus thermophilus and Lactobacillus, and other physical and chemical properties of the yoghurt were investigated.Results: TBF capsules were found to be sphere-shaped with porous surfaces, an average particle size of 1728.67 μm, an encapsulation yield of 92.85 ± 1.98% (w/w), and a glass transition temperature of 152.06 °C. When the TBF capsules were exposed to simulated gastric fluid for 4 h, the TBF release rate was 15.75% (w/w), while in simulated intestinal fluid, the TBF release rate reached 65.99% (w/w) after 1 h. After 5-6 h in simulated intestinal fluid, the TBF release rate reached 100% (w/w). The protein content of the yoghurt with encapsulated TBF was 3.57 ± 0.26% (w/w, p < 0.01), and the numbers of Lactobacillus and Streptococcus thermophilus were 2.45 ± 0.98 × 10⁸ (p < 0.01) and 5.43 ± 2.24 × 10⁷ CFU/mL (p < 0.05), respectively, with strong water retention being detected (p < 0.01). Samples containing the encapsulated TBF exhibited a significantly higher acceptability than the unencapsulated TBF (p < 0.01).Conclusions: Encapsulation using PWP effectively delivers TBF to the small intestine through the stomach. It also masks the bitter taste, enhances the colour of TBF-containing yoghurt, and improves the physical and chemical properties of the yoghurt.