Quercetin alleviates predator stress-induced anxiety-like and brain oxidative signs in pregnant rats and immune count disturbance in their offspring

Quercetin ameliorates cognitive deficit, expression of amyloid precursor gene, and pro-inflammatory cytokines in an experimental models of Alzheimer's disease in Wistar rats

Chronic stress (CS) is critically involved in the Alzheimer's disease (AD) pathogenesis resulting in cognitive disturbance. Also, amyloid precursor protein (APP) related gens, pro-inflammatory cytokines, and stress increases AD-related pathogenesis through increasing APP, all are important players in the development of AD. Herein, we explore the possible neuroprotective and anti-amnestic effect of quercetin (QUER) on cognitive deficits induced by scopolamine (SCOP) in stressed rats. Stress induction was performed by exposed of rats to 2-h chronic restraint stress for 10 days. Then rats were supplemented with QUER (25 mg/kg/day oral gavage, for 1 month). Ratswere submitted to intraperitoneal (i.p.) injection of SCOP (1 mg/kg) during the final 9 days of QUER supplementation to induce dementia like condition. Following the interventions, behavioral tests [elevated plus maze (EPM) and novel object recognition memory (NORM)] was examined to analysis the cognitive functions. Meanwhile, prefrontal cortex (PFC) and hippocampus of brain were used for gene expression and biochemical studies. Also, the plasma corticosterone (CORT) level was measured. We established that administration of QUER ameliorated the SCOP-related memory impairment. Also, QUER decreased stress related anxiety like behaviors in the EPM. QUER also altered the interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) levels in both PFC and hippocampus of SCOP treated rats in stress and non-stress conditions. We found that QUER increased APP and amyloid precursor-like protein 2 (APLP2) mRNA expression in both non-stress and stressed rats. Also, our findings imply that QUER suppress the effect of SCOP on cognitive functions. Moreover, decreased APP mRNA expression in the hippocampus were observed following pretreatment of rats with QUER in both stress and non-stress groups. Given that decreased amyloid beta (Aβ) expression in the hippocampus of stressed rats, it can be proposed that elevations in APP mRNA expression by QUER activates non-amyloidogenic pathways leading to reduction in Aβ levels. However, our findings indicate that QUER can be a therapeutic candidate, which exerts an anti-amnesic property against SCOP-induced memory decline. On the other hand, prior QUER administration in stress condition could be a promising approach against AD prevention.

A comprehensive and systematic review of the potential neuroprotective effect of quercetin in rat models of spinal cord injury

CONTEXT

Spinal cord injury (SCI) is a potentially fatal neurological disease with severe complications and a high disability rate. An increasing number of animal experimental studies support the therapeutic effect of quercetin, which is a natural anti-inflammatory and antioxidant bioflavonoid.

OBJECTIVE

This paper reviewed the therapeutic effect of quercetin on a rat SCI model and summarized the relevant mechanistic research.

DATA SOURCES

PubMed, EMBASE, Web of Science, Science Direct, WanFang Data, SinoMed databases, the China National Knowledge Infrastructure, and the Vip Journal Integration Platform were searched from their inception to April 2023 for animal experiments applying quercetin to treat SCI.

STUDY SELECTION

Based on the PICOS criteria, a total of 18 eligible studies were included, of which 14 were high quality.

RESULTS

In this study, there was a gradual increase in effect based on the Basso, Beattie, and Bresnahan (BBB) score after three days (p < 0.0001). Furthermore, gender differences also appeared in the efficacy of quercetin; males performed better than females (p = 0.008). Quercetin was also associated with improved inclined plane test score (p = 0.008). In terms of biochemical indicators, meta-analysis showed that MDA (p < 0.0001) and MPO (p = 0.0002) were significantly reduced after quercetin administration compared with the control group, and SOD levels were increased (p = 0.004). Mechanistically, quercetin facilitates the inhibition of oxidative stress, inflammation, autophagy and apoptosis that occur after SCI.

CONCLUSIONS

Generally, this systematic review suggests that quercetin has a neuroprotective effect on SCI.

Natural products from Odontonema strictum promote neurite outgrowth in neuronal PC12 cells

The leaves of Odontonema strictum, a tropical plant used for its antihypertensive properties, are rich in nutrients and biologically active phytochemicals, such as β-sitosterol, stigmasterol, umuravumbolide, deacetylumuravumbolide, dideacetylboronolide, deacetylboronolide, verbascoside, and isoverbascoside. In addition, its roots are rich in β-sitosterol, stigmasterol, and the iridoid glycoside β-O-methyl-unedoside. Ingestion of the roots was reported to have a sedative effect in a dog was previously reported on a dog eating the roots of this plant. In the present study, we report for the first time the cell proliferation- and neurite outgrowth-promoting effects in PC12 neuronal cells of the isolated organic compounds and crude extracts from O. strictum. Pituitary adenylate cyclase-activating peptide (PACAP) and quercetin were used as positive controls. At the concentration of 0.2 μg/mL, β-sitosterol was more potent than quercetin and displayed the same activity (>45 μm/cell) as PACAP (100 nM). At a low concentration (0.04 μg/mL), verbascoside and isoverbascoside showed the strongest neurite outgrowth-promoting effect (neurite length of 30 to 35 μm/cell). Our results indicate that phytomedicines made from O. strictum may be useful in preventing neurodegenerative diseases.

The anxiolytic and circadian regulatory effect of agarwood water extract and its effects on the next generation; zebrafish modelling

Anxiety is one of the most common psychiatric symptoms worldwide. Studies show that there is an increase of >25 % in the prevalence of anxiety with the onset of the COVID-19 pandemic process. Due to the various side effects of drugs used in the treatment of anxiety, interest in natural therapeutic alternatives has increased. Agarwood is a plant used as a natural therapeutic due to its sedative effect as well as many effects such as antioxidant and antibacterial. Although there are many studies with agarwood, comprehensive behavioral studies, including the next generation, are limited. In present study, zebrafish fed with diets containing 10-100 ppm water extract of Agarwood (AWE) for 3 and 8 weeks were exposed to predator stress using Oscar fish in order to test the potential anxiolytic effect of AWE. At the end of the period, zebrafish exposed to predator stress were subjected to anxiety and circadian tests. Histopathological evaluation and immunofluorescent analyzes of BDNF and 5HT4-R proteins were performed in the brains of zebrafish. The effects on the next generation were examined by taking offspring from zebrafish. According to the results, it was observed that AWE had a healing effect on anxiety-like behaviors and on the disrupted circadian rhythm triggered by the predatory stress it applied, especially in the 8 weeks 100 ppm group. Interestingly, it was also found to be effective in offspring of zebrafish fed diets with AWE.

Exploring the potential of intranasally administered naturally occurring quercetin loaded into polymeric nanocapsules as a novel platform for the treatment of anxiety

Anxiety is one of the most prevalent forms of psychopathology that affects millions worldwide. It gained more importance under the pandemic status that resulted in higher anxiety prevalence. Anxiolytic drugs such as benzodiazepines have an unfavorable risk/benefit ratio resulting in a shift toward active ingredients with better safety profile such as the naturally occurring quercetin (QRC). The delivery of QRC is hampered by its low water solubility and low bioavailability. The potential to enhance QRC delivery to the brain utilizing polymeric nanocapsules administered intranasally is investigated in the current study. Polymeric nanocapsules were prepared utilizing the nanoprecipitation technique. The best formula displayed a particle size of 227.8 ± 11.9 nm, polydispersity index of 0.466 ± 0.023, zeta potential of - 17.5 ± 0.01 mV, and encapsulation efficiency % of 92.5 ± 1.9%. In vitro release of QRC loaded polymeric nanocapsules exhibited a biphasic release with an initial burst release followed by a sustained release pattern. Behavioral testing demonstrated the superiority of QRC loaded polymeric nanocapsules administered intranasally compared to QRC dispersion administered both orally and intranasally. The prepared QRC loaded polymeric nanocapsules also demonstrated good safety profile with high tolerability.

A Flavonoid on the Brain: Quercetin as a Potential Therapeutic Agent in Central Nervous System Disorders

Quercetin is one of the most common, naturally occurring flavonoids, structurally classified to the flavonol subfamily. This compound, found in many edible and medicinal plants either as a free or glycosidated form, has been scientifically exploited for many years, and one could hardly expect it could be a hero of some additional story. Commonly recognized as an anti-inflammatory agent, quercetin not only limits capillary vessel permeability by inhibiting hyaluronidase but also blocks cyclooxygenases and lipoxygenases. As a typical flavonoid, it is also known for its antioxidant effect, which was confirmed by many in vitro and in vivo studies. Throughout the years, numerous other activities were reported for quercetin, including antidiabetic, anti-proliferative, or anti-viral. Of note, recent data have revealed its potential role as a therapeutic agent for several central nervous system disorders. This review provides an overview of available experimental data on quercetin and its complexes with respect to central nervous system diseases, with a main focus on some aspects that were not discussed previously, such as anti-anxiolytic effects, anti-Huntington’s disease activity, or therapeutic potential in brain cancer. Moreover, quercetin’s protective role in some of these diseases is discussed, especially as an anti-neuroinflammatory agent. Bearing in mind the poor bioavailability of this compound, possible options that would enhance its delivery to the site of action are also presented.

Perinatal diet and offspring anxiety: A scoping review

Health behaviors during pregnancy have an impact on the developing offspring. Dietary factors play a role in the development of mental illness: however, less is known about the impact of diet factors during pre-conception, gestation, and lactation on anxiety levels in offspring. This scoping review sought to systematically map the available research involving human and animal subjects to identify nutritional interventions which may have a harmful or protective effect, as well as identify gaps. Studies investigating an association between any perinatal diet pattern or diet constituent and offspring anxiety were included. The number of studies reporting an association with increased or decreased levels of anxiety were counted and presented in figures. A total of 55,914 results were identified as part of a larger scoping review, and 120 articles met the criteria for inclusion. A greater intake of phytochemicals and vitamins were associated with decreased offspring anxiety whereas maternal caloric restriction, protein restriction, reduced omega-3 consumption, and exposure to a high fat diet were associated with higher levels of offspring anxiety. Results were limited by a very large proportion of animal studies. High quality intervention studies involving human subjects are warranted to elucidate the precise dietary factors or constituents that modulate the risk of anxiety in offspring.

Study on the Antianxiety Mechanism of Suanzaoren Decoction Based on Network Pharmacology and Molecular Docking

Objective. Suanzaoren Decoction (SZRT) is a classic decoction to calm the nerves in traditional Chinese medicine (TCM). It has been extensively treated as an antianxiety drug in modern times, but the material basis and pharmacological mechanisms are still unclear. To explore the material basis and corresponding potential targets, as well as to elucidate the mechanism of SZRT, network pharmacology and molecular docking methods were utilized. Methods. The main chemical compounds and potential targets of SZRT were collected from the pharmacological database analysis platform (TCMSP). Anxiety targets were obtained from the GeneCards database. Then, a target compound network was established using overlapping genes and the corresponding potential compounds. Protein interaction analysis, GO enrichment, and KEGG pathway enrichment were performed using the STRING database, DAVID database, and KOBAS database. Finally, molecular docking was conducted between MAOB and its corresponding active compound in SZRT to further verify the results. Results. A total of 137 active components in SZRT were screened from the TCMSP database, and 210 corresponding targets were predicted. A total of 5434 anxiety-related targets were obtained from the disease target database, and finally 22 potential targets of SZRT on antianxiety were obtained. The constructed C-T network showed that the average degree of active components was 5.4, and four of them interacted with six or more targets. PPI analysis shows that key genes such as MAOA, MAOB, IL1B, TNF, NR3CI, and HTR3A were identified as potential therapeutic targets. A pathway analysis showed that SZRT may participate in neurotransmitter regulation and immunoregulation in a synergistic way to treat anxiety. The binding energy between the active compounds and MAOB was low, indicating good binding. The results of molecular docking showed that all the 10 active ingredients were able to successfully dock with MAOB, and the binding energy of coumaroyltyramine with MAOB was the lowest, that is, −9.6 kcal/mol, and the binding method was hydrogen bonding. Conclusions. SZRT produces antianxiety effects mainly by affecting the neurotransmitter release, transmission, and immunoregulation. This study provides a new approach to elucidating the molecular mechanism and material basis of SZRT in the treatment of anxiety, and it will also benefit the application of TCM in modern medicine.

Maternal polyphenol intake impairs cerebellar redox homeostasis in newborn rats

INTRODUCTION

Polyphenols are compounds found in plants that have been extensively studied due to the health benefits of its consumption in adulthood. Meanwhile, recent evidence suggests that polyphenol consumption during pregnancy may not be safe for the fetus.

OBJECTIVE

The goal of this study was to evaluate the effect of naringenin supplementation during pregnancy on brain redox homeostasis and mitochondrial activity of the newborn rat.

METHODS

Adult female Wistar rats were divided into two groups: (1) vehicle (1 mL/Kg p.o.) or (2) naringenin (50 mg/Kg p.o.). Naringenin was administered once a day during pregnancy. The offspring were euthanized on postnatal day 7, as well the dams, and brain regions were dissected.

RESULTS

The offspring cerebellum was the most affected region, presenting increased activity of the mitochondrial electron transport system, allied to increased reactive species levels, lipid peroxidation, and glutathione concentration. The nitric oxide levels suffered structure-dependent alteration, with decreased levels in the pups' cerebellum and increased in the hippocampus. The offspring parietal cortex was not affected, as well as the parameters evaluated in the dams' brains.

CONCLUSION

Maternal consumption of naringenin alters offspring cerebellar redox homeostasis, which could be related to adverse effects on the motor and cognitive development in the descendants.

Sex Differences in Placental Protein Expression and Efficiency in a Rat Model of Fetal Programming Induced by Maternal Undernutrition

Fetal undernutrition programs cardiometabolic diseases, with higher susceptibility in males. The mechanisms implicated are not fully understood and may be related to sex differences in placental adaptation. To evaluate this hypothesis, we investigated placental oxidative balance, vascularization, glucocorticoid barrier, and fetal growth in rats exposed to 50% global nutrient restriction from gestation day 11 (MUN, n = 8) and controls (n = 8). At gestation day 20 (G20), we analyzed maternal, placental, and fetal weights; oxidative damage, antioxidants, corticosterone, and PlGF (placental growth factor, spectrophotometry); and VEGF (vascular endothelial growth factor), 11β-HSD2, p22^phox, XO, SOD1, SOD2, SOD3, catalase, and UCP2 expression (Western blot). Compared with controls, MUN dams exhibited lower weight and plasma proteins and higher corticosterone and catalase without oxidative damage. Control male fetuses were larger than female fetuses. MUN males had higher plasma corticosterone and were smaller than control males, but had similar weight than MUN females. MUN male placenta showed higher XO and lower 11β-HSD2, VEGF, SOD2, catalase, UCP2, and feto-placental ratio than controls. MUN females had similar feto-placental ratio and plasma corticosterone than controls. Female placenta expressed lower XO, 11β-HSD2, and SOD3; similar VEGF, SOD1, SOD2, and UCP2; and higher catalase than controls, being 11β-HSD2 and VEGF higher compared to MUN males. Male placenta has worse adaptation to undernutrition with lower efficiency, associated with oxidative disbalance and reduced vascularization and glucocorticoid barrier. Glucocorticoids and low nutrients may both contribute to programming in MUN males.

Tricarboxylic acid cycle dehydrogenases inhibition by naringenin: experimental and molecular modelling evidence

The study of polyphenols’ effects on health has been gaining attention lately. In addition to reacting with important enzymes, altering the cell metabolism, these substances can present either positive or negative metabolic alterations depending on their consumption levels. Naringenin, a citrus flavonoid, already presents diverse metabolic effects. The objective of this work was to evaluate the effect of maternal naringenin supplementation during pregnancy on the tricarboxylic acid cycle activity in offspring’s cerebellum. Adult female Wistar rats were divided into two groups: (1) vehicle (1 ml/kg by oral administration (p.o.)) or (2) naringenin (50 mg/kg p.o.). The offspring were euthanised at 7th day of life, and the cerebellum was dissected to analyse citrate synthase, isocitrate dehydrogenase (IDH), α-ketoglutarate dehydrogenase (α-KGDH) and malate dehydrogenase (MDH) activities. Molecular docking used SwissDock web server and FORECASTER Suite, and the proposed binding pose image was created on UCSF Chimera. Data were analysed by Student’s t test. Naringenin supplementation during pregnancy significantly inhibited IDH, α-KGDH and MDH activities in offspring’s cerebellum. A similar reduction was observed in vitro, using purified α-KGDH and MDH, subjected to pre-incubation with naringenin. Docking simulations demonstrated that naringenin possibly interacts with dehydrogenases in the substrate and cofactor binding sites, inhibiting their function. Naringenin administration during pregnancy may affect cerebellar development and must be evaluated with caution by pregnant women and their physicians.

Antioxidant Enzyme Activities Vary with Predation Risk and Environmental Conditions in Free-Living Passerine Birds

Prolonged physiological stress response may lead to an excessive production of reactive oxygen species (ROS) and ultimately to oxidative stress and severe fitness costs. We investigated whether natural variation in predation risk, induced by pygmy owls (Glaucidium passerinum), modifies the oxidative status of two free-living food-supplemented passerine bird species-the great tit (Parus major) and the willow tit (Poecile montanus)-in March 2012 and 2013. Predation risk significantly affected antioxidant enzyme activities of willow tits. Antioxidant enzyme activities (principal component factor 2 [PC2] representing glutathione-S-transferase and superoxide dismutase activities) were higher in high predation risk areas in 2013 than in low predation risk areas in the same year. Higher enzyme activities may suggest higher ROS production in birds living under high predation risk. In addition, antioxidant enzyme activities (PC2) were also higher in high predation risk areas in 2013 than in high predation risk areas in the previous year, 2012. This may represent variation in the risk represented by pygmy owls, which is probably inversely related to the natural fluctuations in the densities of their main prey, voles. In willow tits, PC1 (representing catalase, total glutathione, the ratio of reduced to oxidized glutathione, and protein carbonylation) was not affected by perceived predation risk, nor were antioxidant levels or enzyme activities in great tits. Higher enzyme activities observed in willow tits suggest that predator presence can modify the antioxidant status of avian prey, but the response also seem to be influenced by other environmental characteristics, like harsh winter conditions.

Effects of isopentyl ferulate on oxidative stress biomarkers and a possible GABAergic anxiolytic-like trait in Swiss mice

This study aimed to evaluate the anxiolytic-like effect and the possible neuronal mechanism of action of isopentyl ferulate (IF). For this purpose, we used the marble burying test in Swiss albino mice. The biomarkers involved in oxidative stress were measured in the hippocampus homogenate of the test animals. In addition, the toxicity and antioxidant capacities were tested in Artemia salina and rat erythrocytes, respectively. The results suggest that, an acute administration of the IF at doses of 25, 50, 75 and 150 mg/kg (intraperitoneal, i.p.) significantly (p < 0.05) reduced the marble burying behavior of the animals as compared to the vehicle group, which demonstrates a calming effect of this chemical. It was observed that, the pre-treatment with flumazenil (2.5 mg/kg, i.p.), an antagonist of the gamma-amino butyrinc acid (GABA_A) receptor, significantly reversed the marble burying behavioral activity in the animals treated with the IF 150 mg/kg dose. Moreover, the reduction in nitrite content and lipid peroxidation levels, while an increased in the reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT) activities were also observed their hippocampus. Although, IF (2.36-14.16 mM) did not show toxicity in A. salina but exhibited a prominent antioxidant capacity in hydrogen peroxide-induced oxidative damage in rat erythrocytes. In conclusion, IF exhibited an anxiety-like effect in mice along with a potent antioxidant capacity, and we suppose it may have neuroprotective effects possibly via GABAergic transmission pathway.

Developmental origins of inflammatory and immune diseases

Epidemiological and experimental animal studies show that suboptimal environments in fetal and neonatal life exert a profound influence on physiological function and risk of diseases in adult life. The concepts of the 'developmental programming' and Developmental Origins of Health and Diseases (DOHaD) have become well accepted and have been applied across almost all fields of medicine. Adverse intrauterine environments may have programming effects on the crucial functions of the immune system during critical periods of fetal development, which can permanently alter the immune function of offspring. Immune dysfunction may in turn lead offspring to be susceptible to inflammatory and immune diseases in adulthood. These facts suggest that inflammatory and immune disorders might have developmental origins. In recent years, inflammatory and immune disorders have become a growing health problem worldwide. However, there is no systematic report in the literature on the developmental origins of inflammatory and immune diseases and the potential mechanisms involved. Here, we review the impacts of adverse intrauterine environments on the immune function in offspring. This review shows the results from human and different animal species and highlights the underlying mechanisms, including damaged development of cells in the thymus, helper T cell 1/helper T cell 2 balance disturbance, abnormal epigenetic modification, effects of maternal glucocorticoid overexposure on fetal lymphocytes and effects of the fetal hypothalamic-pituitary-adrenal axis on the immune system. Although the phenomena have already been clearly implicated in epidemiologic and experimental studies, new studies investigating the mechanisms of these effects may provide new avenues for exploiting these pathways for disease prevention.

Restraint stress alters immune parameters and induces oxidative stress in the mouse uterus during embryo implantation

The influence of stress on embryo implantation is not well understood. Prior studies have focused on later gestational stages and the long-term impact of stress on immune function. The objective of this study is to investigate the effects of restraint stress on the immune parameters and the oxidative states of the uterus during implantation. In this study, pregnant CD1 mice were subjected to restraint stress (4 h/d) on embryonic day 1 (E1) and sacrificed on E3, E5, and E7. Maternal plasma corticosterone (CORT) secretion and implantation sites in the uterus were examined. The uterine (excluding embryos) homogenate and uterine lymphocytes were collected to examine oxidative stress states and associated immune parameters. The results demonstrated that restraint stress increased maternal plasma CORT secretion and reduced the number of implantation sites by 15.3% on E5 and by 26.1% on E7. Moreover, restraint stress decreased the density of uterine natural killer (uNK) cells in the endometrium by 22.1-47.9% and increased the density of mast cells in the myometrium by 55.6-76.9%. Restraint stress remarkably decreased the CD3(+)CD4(+) T/CD3(+)CD8(+) T cell ratio (by 26.2-28.9%) and attenuated uterine lymphocyte proliferation and secretion of cytokines. In addition, restraint stress threatened the intracellular equilibrium between oxidants and antioxidants, resulting in decreased glutathione peroxidase (GSH-PX) (32.2% and 45.7%), superoxide dismutase (SOD) (15.5% and 26.1%), and total antioxidant capacity (T-AOC) (18.4% and 18.2%) activities and increased malondialdehyde (MDA) (34.4% and 43.0%) contents on E5 and E7. In conclusion, these findings demonstrate that restraint stress causes abnormal implantation and negatively impacts immune parameters in association with oxidative stress in mice.

Oxidative imbalance and anxiety disorders

The oxidative imbalance appears to have an important role in anxiety development. Studies in both humans and animals have shown a strong correlation between anxiety and oxidative stress. In humans, for example, the increased malondialdehyde levels and discrepancies in antioxidant enzymes in erythrocytes have been observed. In animals, several studies also show that anxiety-like behavior is related to the oxidative imbalance. Moreover, anxiety-like behavior can be caused by pharmacological-induced oxidative stress. Studies using knockout or overexpression of antioxidant enzymes have shown a relationship between anxiety-like behavior and oxidative stress. Related factors of oxidative stress that could influence anxious behavior are revised, including impaired function of different mitochondrial proteins, inflammatory cytokines, and neurotrophic factors. It has been suggested that a therapy specifically focus in reducing reactive species production may have a beneficial effect in reducing anxiety. However, the neurobiological pathways underlying the effect of oxidative stress on anxiety symptoms are not fully comprehended. The challenge now is to identify the oxidative stress mechanisms likely to be involved in the induction of anxiety symptoms. Understanding these pathways could help to clarify the neurobiology of the anxiety disorder and provide tools for new discovery in therapies and preventive strategies.