Naturally Derived Polyphenols Protect Against Corticosterone-Induced Changes in Primary Cortical Neurons

Quercetin alleviates difenoconazole-induced growth inhibition in carp through intestinal-brain axis

Difenoconazole (DIF) is frequently used for the management of fungal infections in fruit and vegetables and excessive residues in the aquatic environment can have adverse effects on fish such as growth inhibition. A treatment based on the dietary additive quercetin (QUE) is a promising approach to positively regulate the state of fish growth. This study focused on whether and how QUE alleviated DIF-induced growth inhibition in fish. In this study, carp were exposed to DIF (0.3906 mg/L) for consecutive 30 d, which showed growth inhibition. Disruption of the intestinal barrier led to elevated levels of intestinal lipopolysaccharide (LPS) and an inflammatory response. Through the intestinal-brain axis, LPS entered the brain where it disrupted the blood-brain barrier, triggered neuroinflammation, caused brain cell apoptosis, and damaged nerves in addition to other things. The dietary supplementation of QUE (400 mg/kg) reduced the levels of LPS in the intestinal and brain, while reducing inflammation and increasing the expression of appetite factors, thereby reducing growth inhibition in carp. This work provided evidence for QUE from the intestinal-brain axis perspective as a potential candidate for alleviating growth inhibition in fish.

Dietary Flavonoid Quercetin Supplement Promotes Antiviral Innate Responses Against Vesicular Stomatitis Virus Infection by Reshaping the Bacteriome and Host Metabolome in Mice

SCOPE

Active ingredients in functional foods exhibit broad-spectrum antiviral activity. The objective of this study is to investigate the protective effect of quercetin derived from bee propolis, a natural product with antiviral activity and modulating effects on the gut microbiota, against vesicular stomatitis virus (VSV) infection.

METHODS AND RESULTS

Through a cellular-based study, this study demonstrates that quercetin can modulate the activity of interferon-regulating factor 3 (IRF3). In vivo, it shows that quercetin protects mice from VSV infection by enhancing interferon production and inhibiting the production of proinflammatory cytokines. The study conducts 16S rRNA-based gut microbiota and nontargets metabolomics analyses to elucidate the mechanisms underlying quercetin-mediated bidirectional communication between the gut microbiome and host metabolome during viral infection. Quercetin not only ameliorates VSV-induced dysbiosis of the intestinal flora but also alters serum metabolites related to lipid metabolism. Cross-correlations between the gut bacteriome and the serum metabolome indicate that quercetin can modulate phosphatidylcholine (16:0/0:0) and 5-acetylamino-6-formylamino-3-methyluracil to prevent VSV infection.

CONCLUSION

This study systematically elucidates the anti-VSV mechanism of quercetin through gut bacteriome and host metabolome assays, offering new insights into VSV treatment and revealing the mechanisms behind a novel disease management strategy using dietary flavonoid supplements.

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Harnessing the power of nutritional antioxidants against adrenal hormone imbalance-associated oxidative stress

Oxidative stress, resulting from dysregulation in the secretion of adrenal hormones, represents a major concern in human health. The present review comprehensively examines various categories of endocrine dysregulation within the adrenal glands, encompassing glucocorticoids, mineralocorticoids, and androgens. Additionally, a comprehensive account of adrenal hormone disorders, including adrenal insufficiency, Cushing's syndrome, and adrenal tumors, is presented, with particular emphasis on their intricate association with oxidative stress. The review also delves into an examination of various nutritional antioxidants, namely vitamin C, vitamin E, carotenoids, selenium, zinc, polyphenols, coenzyme Q10, and probiotics, and elucidates their role in mitigating the adverse effects of oxidative stress arising from imbalances in adrenal hormone levels. In conclusion, harnessing the power of nutritional antioxidants has the potential to help with oxidative stress caused by an imbalance in adrenal hormones. This could lead to new research and therapeutic interventions.

Natural Products as Modulators of Nrf2 Signaling Pathway in Neuroprotection

Neurodegenerative diseases (NDs) affect the West due to the increase in life expectancy. Nervous cells accumulate oxidative damage, which is one of the factors that triggers and accelerates neurodegeneration. However, cells have mechanisms that scavenge reactive oxygen species (ROS) and alleviate oxidative stress (OS). Many of these endogenous antioxidant systems are regulated at the gene expression level by the transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2). In the presence of prooxidant conditions, Nrf2 translocates to the nucleus and induces the transcription of genes containing ARE (antioxidant response element). In recent years, there has been an increase in the study of the Nrf2 pathway and the natural products that positively regulate it to reduce oxidative damage to the nervous system, both in in vitro models with neurons and microglia subjected to stress factors and in vivo models using mainly murine models. Quercetin, curcumin, anthocyanins, tea polyphenols, and other less studied phenolic compounds such as kaempferol, hesperetin, and icariin can also modulate Nrf2 by regulating several Nrf2 upstream activators. Another group of phytochemical compounds that upregulate this pathway are terpenoids, including monoterpenes (aucubin, catapol), diterpenes (ginkgolides), triterpenes (ginsenosides), and carotenoids (astaxanthin, lycopene). This review aims to update the knowledge on the influence of secondary metabolites of health interest on the activation of the Nrf2 pathway and their potential as treatments for NDs.

Progress of Research into Novel Drugs and Potential Drug Targets against Porcine Pseudorabies Virus

Pseudorabies virus (PRV) is the causative agent of pseudorabies (PR), infecting most mammals and some birds. It has been prevalent around the world and caused huge economic losses to the swine industry since its discovery. At present, the prevention of PRV is mainly through vaccination; there are few specific antivirals against PRV, but it is possible to treat PRV infection effectively with drugs. In recent years, some drugs have been reported to treat PR; however, the variety of anti-pseudorabies drugs is limited, and the underlying mechanism of the antiviral effect of some drugs is unclear. Therefore, it is necessary to explore new drug targets for PRV and develop economic and efficient drug resources for prevention and control of PRV. This review will focus on the research progress in drugs and drug targets against PRV in recent years, and discuss the future research prospects of anti-PRV drugs.

Synergistic Effect of Quercetin on Antibacterial Activity of Florfenicol Against Aeromonas hydrophila In Vitro and In Vivo

The overuse or abuse of antimicrobial drugs in aquaculture, aggravates the generation of drug-resistant bacteria, which has caused potential risks to human health and the aquaculture industry. Flavonoid–antibiotic combinations have been shown to suppress the emergence of resistance in bacteria, and sometimes even reverse it. Here, the antibacterial activity of florfenicol in combination with quercetin, a potential drug to reverse multidrug resistance, was tested against Aeromonas hydrophila (A. hydrophila). Of eleven selected antimicrobial agents, quercetin and florfenicol showed the strongest bactericidal effect, and fractional inhibitory concentration (FIC) indices were 0.28, showing a highly synergistic effect. Then, the antibacterial activities of quercetin and florfenicol against A. hydrophila were further tested in vitro and in vivo. Bacterial viability of A. hydrophila decreased in a florfenicol dose-dependent manner, about 16.3–191.4-fold lower in the presence of 15 μg/mL quercetin and 0.156 to 1.25 μg/mL florfenicol than in the absence of quercetin, respectively. The cell killing was maximum at 45 μg/mL quercetin in the dose range tested plus 0.156 μg/mL florfenicol. The viability decreased over time during the combined treatment with quercetin and florfenicol by 60.5- and 115-fold in 0.156 μg/mL florfenicol and 0.625 μg/mL florfenicol, respectively. Additionally, the synergistic effect was confirmed by the bacterial growth curve. Furthermore, quercetin and florfenicol had an obvious synergistic activity in vivo, reducing the bacterial load in the liver, spleen and kidney tissues of Cyprinus carpio up to 610.6-fold compared with the florfenicol group, and improving the survival rate of infected fish from 10% in the control group to 90% in drug combinations group. These findings indicated that quercetin could potentiate the antibacterial activity of florfenicol against A. hydrophila infection and may reduce the use of antimicrobial drugs and improve the prevention and control capability of bacterial resistance.

The Advent of Nutrigenomics: A Narrative Review with an Emphasis on Psychological Disorders

A new research field is emerging that combines nutrition and genetics at the molecular level, namely nutrigenomics. Several aspects of nutrigenomics are examined in this review, with a particular focus on psychological disorders. The origin of this field in the 20th century and its modern developments have been investigated. Various studies have reported the impact of genetic factors and diet on various chronic disorders, elucidating how the deficiency of several macronutrients results in significant ailments, including diabetes, cancer, cardiovascular disorders, and others. Furthermore, the application of nutrigenomics to diet and its impact on the global disease rate and quality of life have been discussed. The relationship between diet and gene expression can facilitate the classification of diet-gene interactions and the diagnosis of polymorphisms and anomalies. Numerous databases and research tools for the study of nutrigenomics are essential to the medical application of this field. The nutrition-gene interrelationships can be utilized to study brain development, impairment, and diseases, which could be a significant medical breakthrough. It has also been observed that psychological conditions are exacerbated by the interaction between gut microbes and the prevalence of malnutrition. This article focuses on the impact of nutrition on genes involved in various psychological disorders and the potential application of nutrigenomics as a revolutionary treatment method.

Adipose stem cell-derived extracellular vesicles ameliorates corticosterone-induced apoptosis in the cortical neurons via inhibition of ER stress

Background

Corticosterone (CORT) can induce neuronal damage in various brain regions, including the cerebral cortex, the region implicated in depression. However, the underlying mechanisms of these CORT-induced effects remain poorly understood. Recently, many studies have suggested that adipose stem cell-derived extracellular vesicles (A-EVs) protect neurons in the brain.

Methods

To investigated neuroprotection effects of A-EVs in the CORT-induced cortical neurons, we cultured cortical neurons from E15 mice for 7 days, and the cultured cortical neurons were pretreated with different numbers (5 × 10⁵–10⁷ per mL) of A-EVs (A-EVs⁵, A-EVs⁶, A-EVs⁷) for 30 min followed by administration of 200 μM CORT for 24 h.

Results

Here, we show that A-EVs exert antiapoptotic effects by inhibiting endoplasmic reticulum (ER) stress in CORT-induced cortical neurons. We found that A-EVs prevented neuronal cell death induced by CORT in cultured cortical neurons. More importantly, we found that CORT exposure in cortical neurons resulted in increased levels of apoptosis-related proteins such as cleaved caspase-3. However, pretreatment with A-EVs rescued the levels of caspase-3. Intriguingly, CORT-induced apoptosis involved upstream activation of ER stress proteins such as GRP78, CHOP and ATF4. However, pretreatment with A-EVs inhibited ER stress-related protein expression.

Conclusion

Our findings reveal that A-EVs exert antiapoptotic effects via inhibition of ER stress in CORT-induced cell death.

Quercetin as an antiviral agent inhibits the Pseudorabies virus in vitro and in vivo

Pseudorabies virus (PRV) accounts for a critical swine disease incurring economic losses worldwide. Several PRV vaccines are commercially available but these vaccines are effective against only certain prevalent PRV strains in China. To prevent PRV-induced latent infection and decrease the pathogenicity, novel anti-PRV drugs are required to prevent PRV infection. Natural products show exceptional structural diversity representing an important source for developing novel therapeutic agents. Quercetin is a flavonoid with anti-oxidant, anti-cancer, anti-bacterial and anti-viral activities. This study involved quercetin for studying the anti-PRV function in vitro and in vivo. Quercetin was found to significantly decrease the PRV virulent strain HNX at a half-maximal inhibitory concentration (IC₅₀) of 2.618 μM and selectivity index 229. This anti-PRV activity of quercetin was found to be dose-dependent. Furthermore, quercetin also inhibited a wide the infections by a spectrum of PRV strains like HNX, Ea, Bartha and Fa strain. These virucidal effects of quercetin suggest the interaction between these molecules and viral particles, and quercetin is responsible for inhibiting the adsorption of PRV infections. The silico assays suggesting that quercetin might interact with the gD-protein on the surface of the PRV important for viral infection. Additional, the quercetin plantar injection protected the mice from the lethal challenge, decreasing the PRV-infected mice's brain viral loads and mortality. These results provides a anti-PRV strategy and contribute to drug discovery and development.

Prenatal stress and KCl-induced depolarization modulate cell death, hypothalamic-pituitary-adrenal axis genes, oxidative and inflammatory response in primary cortical neurons

Maternal stress has been described as an important component in the offspring's cerebral development, altering the susceptibility to diseases in later life. Moreover, the postnatal period is essential for the development and integration of several peripheral and central systems related to the control of homeostasis. Thus, this study aimed to evaluate the effects of prenatal stress on the activation of cortical neurons, by performing experiments both under basal conditions and after KCl-induced depolarization. Female mice were divided in two groups: control and prenatal restraint stress. Cortical neurons from the offspring were obtained at gestational day 18. The effects of prenatal stress and KCl stimulations on cellular mortality, autophagy, gene expression, oxidative stress, and inflammation were evaluated. We found that neurons from PNS mice have decreased necrosis and autophagy after depolarization. Moreover, prenatal stress modulated the HPA axis, as observed by the increased GR and decreased 5HTr1 mRNA expression. The BDNF is an important factor for neuronal function and results demonstrated that KCl-induced depolarization increased the gene expression of BDNF I, BDNF IV, and TRκB. Furthermore, prenatal stress and KCl treatment induced significant alterations in oxidative and inflammatory markers. In conclusion, prenatal stress and stimulation with KCl may influence several markers related to neurodevelopment in cortical neurons from neonate mice, supporting the well-known long-term effects of maternal stress.

Quercetin: A Bioactive Compound Imparting Cardiovascular and Neuroprotective Benefits: Scope for Exploring Fresh Produce, Their Wastes, and By-Products

Quercetin, a bioactive secondary metabolite, holds incredible importance in terms of bioactivities, which has been proved by in vivo and in vitro studies. The treatment of cardiovascular and neurological diseases by quercetin has been extensively investigated over the past decade. Quercetin is present naturally in appreciable amounts in fresh produce (fruits and vegetables). However, today, corresponding to the growing population and global demand for fresh fruits and vegetables, a paradigm shift and focus is laid towards exploring industrial food wastes and/or byproducts as a new resource to obtain bioactive compounds such as quercetin. Based on the available research reports over the last decade, quercetin has been suggested as a reliable therapeutic candidate for either treating or alleviating health issues, mainly those of cardiovascular and neurological diseases. In the present review, we have summarized some of the critical findings and hypotheses of quercetin from the available databases foreseeing its future use as a potential therapeutic agent to treat cardiovascular and neurological diseases. It is anticipated that this review will be a potential reference material for future research activities to be undertaken on quercetin obtained from fresh produce as well as their respective processing wastes/byproducts that rely on the circular concept.

Going with the grain: Fiber, cognition, and the microbiota-gut-brain-axis

Healthy dietary intake has been acknowledged for decades as one of the main contributors to health. More recently, the field of nutritional psychiatry has progressed our understanding regarding the importance of nutrition in supporting mental health and cognitive function. Thereby, individual nutrients, including omega-3 fatty acids and polyphenols, have been recognized to be key drivers in this relationship. With the progress in appreciating the influence of dietary fiber on health, increasingly research is focusing on deciphering its role in brain processes. However, while the importance of dietary fiber in gastrointestinal and metabolic health is well established, leading to the development of associated health claims, the evidence is not conclusive enough to support similar claims regarding cognitive function. Albeit the increasing knowledge of the impact of dietary fiber on mental health, only a few human studies have begun to shed light onto the underexplored connection between dietary fiber and cognition. Moreover, the microbiota-gut-brain axis has emerged as a key conduit for the effects of nutrition on the brain, especially fibers, that are acted on by specific bacteria to produce a variety of health-promoting metabolites. These metabolites (including short chain fatty acids) as well as the vagus nerve, the immune system, gut hormones, or the kynurenine pathway have been proposed as underlying mechanisms of the microbiota-brain crosstalk. In this minireview, we summarize the evidence available from human studies on the association between dietary fiber intake and cognitive function. We provide an overview of potential underlying mechanisms and discuss remaining questions that need to be answered in future studies. While this field is moving at a fast pace and holds promise for future important discoveries, especially data from human cohorts are required to further our understanding and drive the development of public health recommendations regarding dietary fiber in brain health.

Neurobiological effects of phospholipids in vitro: Relevance to stress-related disorders

Nutrition is a crucial component for maintenance of brain function and mental health. Accumulating evidence suggests that certain molecular compounds derived from diet can exert neuroprotective effects against chronic stress, and moreover improve important neuronal processes vulnerable to the stress response, such as plasticity and neurogenesis. Phospholipids are naturally occurring amphipathic molecules with promising potential to promote brain health. However, it is unclear whether phospholipids are able to modulate neuronal function directly under a stress-related context. In this study, we investigate the neuroprotective effects of phosphatidylcholine (PC), lysophosphatidylcholine (LPC), phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylglycerol (PG), phosphatidic acid (PA), sphingomyelin (SM) and cardiolipin (CL) against corticosterone (CORT)-induced cytotoxicity in primary cultured rat cortical neurons. In addition, we examine their capacity to modulate proliferation and differentiation of hippocampal neural progenitor cells (NPCs).

We show that PS, PG and PE can reverse CORT-induced cytotoxicity and neuronal depletion in cortical cells. On the other hand, phospholipid exposure was unable to prevent the decrease of Bdnf expression produced by CORT. Interestingly, PS was able to increase hippocampal NPCs neurosphere size, and PE elicited a significant increase in astrocytic differentiation in hippocampal NPCs. Together, these results indicate that specific phospholipids protect cortical cells against CORT-induced cytotoxicity and improve proliferation and astrocytic differentiation in hippocampal NPCs, suggesting potential implications on neurodevelopmental and neuroprotective pathways relevant for stress-related disorders.

Polyphenols selectively reverse early-life stress-induced behavioural, neurochemical and microbiota changes in the rat

There is a growing emphasis on the role of the microbiota-gut-brain axis as modulator of host behaviour and as therapeutic target for neuropsychiatric disorders. In addition, accumulating evidence suggests that early-life stress can exert long-lasting changes on the brain and microbiota, and this early adversity is associated with increased risk for developing depression in later life. The maternal separation (MS) model in rats is a robust paradigm to study the effects of early-life stress on the microbiota-gut-brain axis. Recently, we have shown that polyphenols, naturally occurring compounds associated with several health benefits, have anti-stress effects in in vitro models. In this study, we assess the therapeutic potential of a variety of both flavonoid and non-flavonoid polyphenols in reversing the impact of MS on behaviour and the microbiota-gut-brain axis. Rats underwent a dietary intervention with the naturally-derived polyphenols xanthohumol and quercetin, as well as with a phlorotannin extract for 8 weeks. Treatment with polyphenols prevented the depressive- and anxiety-like behaviours induced by MS, where xanthohumol effects were correlated with rescue of BDNF plasma levels. In addition, MS resulted in altered brain levels of 5-hydroxyindoleacetic acid (5-HIAA) and dopamine, accompanied by abnormal elevation of plasma corticosterone. Although polyphenols did not reverse neurotransmitter imbalance, xanthohumol normalised corticosterone levels in MS rats. Finally, we explored the impact of MS and polyphenolic diets on the gut microbiota. We observed profound changes in microbial composition and diversity produced by MS condition and by xanthohumol treatment. Moreover, functional prediction analysis revealed that MS results in altered enrichment of pathways associated with microbiota-brain interactions that are significantly reversed by xanthohumol treatment. These results suggest that naturally-derived polyphenols exert antidepressant-like effects in MS rats, which mechanisms could be potentially mediated by HPA regulation, BDNF levels rescue and modulation of the microbiota-gut-brain axis.

Corticosterone Induced the Increase of proBDNF in Primary Hippocampal Neurons Via Endoplasmic Reticulum Stress

Major depression disorder is one of the most common psychiatric disorders that greatly threaten the mental health of a large population worldwide. Previous studies have shown that endoplasmic reticulum (ER) stress plays an important role in the pathophysiology of depression, and current research suggests that brain-derived neurotrophic factor precursor (proBDNF) is involved in the development of depression. However, the relationship between ER and proBDNF in the pathophysiology of depression is not well elucidated. Here, we treated primary hippocampal neurons of mice with corticosterone (CORT) and evaluated the relationship between proBDNF and ERS. Our results showed that CORT induced ERS and upregulated the expression of proBDNF and its receptor, Follistatin-like protein 4 (FSTL4), which contributed to significantly decreased neuronal viability and expression of synaptic-related proteins including NR2A, PSD95, and SYN. Anti-proBDNF neutralization and ISRIB (an inhibitor of the ERS) treatment, respective ly, protected neuronal viabilities and increased the expression of synaptic-related proteins in corticosterone-exposed neurons. ISRIB treatment reduced the expression of proBDNF and FSTL4, whereas anti-proBDNF treatment did not affect ERS markers (Grp78, p-PERK, ATF4) expression. Our study presented evidence that CORT-induced ERS negatively regulated the neuronal viability and the level of synaptic-related protein of primary neurons via the proBDNF/FSTL4 pathway.