Quercetin Supplementation Research Articles

Quercetin supplementation in metabolic syndrome: nutrigenetic interactions with the Zbtb16 gene variant in rodent models

BackgroundQuercetin is a promising phytochemical in treating abnormalities associated with metabolic syndrome (MetS). This study aimed to explore the morphometric, metabolic, transcriptomic, and nutrigenetic responses to quercetin supplementation using two genetically distinct MetS models that only differ in the variant of the MetS-related Zbtb16 gene (Zinc Finger And BTB Domain Containing 16).ResultsQuercetin supplementation led to a significant reduction in the relative weight of retroperitoneal adipose tissue in both investigated strains. A decrease in visceral (epididymal) fat mass, accompanied by an increase in brown fat mass after quercetin treatment, was observed exclusively in the SHR strain. While the levels of serum triglycerides decreased within both strains, the free fatty acids levels decreased in SHR-Zbtb16-Q rats only. The total serum cholesterol levels were not affected by quercetin in either of the two tested strains. While there were no significant changes in brown adipose tissue transcriptome, quercetin supplementation led to a pronounced gene expression shift in white retroperitoneal adipose tissue, particularly in SHR-Zbtb16-Q.ConclusionQuercetin administration ameliorates certain MetS-related features; however, the efficacy of the treatment exhibits subtle variations depending on the specific variant of the Zbtb16 gene.

Individual and combined effects of dietary chlorogenic acid and quercetin supplementation on the growth, lipid metabolism and flesh quality of grass carp, Ctenopharyngodon idellus

The purpose of this study was to evaluate the individual and combined effects of dietary chlorogenic acid and quercetin supplementation on the growth, lipid metabolism and flesh quality of Ctenopharyngodon idellus (C. idellus). Fish (59.7 ± 0.3 g) were fed for 60 days with five diets, including a basal diet not added (CON) or added with chlorogenic acid (CGA, 400 mg/kg), quercetin (QC, 400 mg/kg), and their combinations (CGA:QC=1:1) with 400 mg/kg and 800 mg/kg (CGA:QC-400; CGA:QC-800). The weight gain was increased (+4.00 %, +4.41 %), and the feed conversion ratio was decreased (-0.07, -0.08) by individual supplementation with CGA and QC (P<0.05), but not by their combinations (P>0.05). In addition, dietary CGA and QC promoted the apparent digestibility of dry matter and protein and the activities of intestinal amylase and protease (P<0.05). The CGA, QC and CGA:QC-800 groups presented higher activities of flesh superoxide dismutase, flesh glutathione peroxidase (GSH-Px) and serum GSH-Px, as well as lower contents of protein carbonyl and malondialdehyde (MDA) in flesh and MDA in serum than those of CON group (P<0.05). An increase in flesh hardness, water-holding capacity, and total collagen, heat-insoluble collagen and n-3 polyunsaturated fatty acids contents was observed in the CGA, QC and CGA:QC-800 groups (P<0.05). The four supplements reduced mesenteric lipid-somatic index, flesh n-3/n-6 ratio and serum triglycerides (P<0.05), and the CGA:QC-400 and CGA:QC-800 groups also showed lower lipid content in flesh than CON group (P<0.05). Taken together, the individual supplementation of dietary CGA and QC enhanced the growth performance, lipid metabolism and flesh quality of C. idellus, and their combination presented synergistic effect only on lipid metabolism.

Quercetin supplementation improved the growth and health of juvenile Chinese mitten crabs (Eriocheir sinensis) fed low-fishmeal diets

The substitution of fishmeal with plant proteins can induce oxidative stress in aquatic animals and impair their growth and health. Quercetin is a potent natural antioxidant, but its specific effects on the growth and health of Chinese mitten crabs, as well as the underlying molecular mechanisms, remain unclear. This study aimed to investigate the impact of quercetin on the growth, physiological and biochemical parameters, gut microbiota, and transcriptome of juvenile Chinese mitten crabs (Eriocheir sinensis). Crabs (0.53 ± 0.01 g) were randomly divided into seven groups. One group was fed a diet containing normal fishmeal (35 % fishmeal), whereas the other six groups were fed diets containing low levels of fishmeal (15 % fishmeal) supplemented with different levels of quercetin (0, 250, 500, 1000, 2000, or 4000 mg/kg). Each group had four replicate tanks with 40 crabs per 300 L tank, and the experiment lasted for 56 days. The growth performance of the 35 % fishmeal group was significantly greater than that of the 15 % fishmeal group without quercetin. However, quercetin significantly increased the weight gain rate and specific growth rate of juvenile crabs, especially in the 1000 mg/kg quercetin group, where these rates exceeded those of the normal fishmeal group. The antioxidant capacity and immunity of the 35 % fishmeal group were significantly greater than those of the 15 % fishmeal group. However, quercetin supplementation promoted the antioxidant capacity and immunity of the crabs. Quercetin supplementation at 4000 mg/kg changed the gut microbiota structure by decreasing beneficial bacteria and increasing pathogenic bacteria. Quercetin supplementation enhanced the growth performance and antioxidant capacity of Chinese mitten crabs by increasing glutamate metabolism, pantothenic acid and Coenzyme A biosynthesis, sphingolipid metabolism, arachidonic acid metabolism, and cysteine and methionine metabolism. This study revealedthat dietary supplementation with quercetin can promote Chinese mitten crab growth, antioxidant capacity, and nonspecific immunity; improve gut morphology; and promote gut microbiota homeostasis. The optimal dietary concentration of 688–695 mg/kg is recommended on the basis of weight gain and specific growth rate analyses.

Water-soluble sulfur quantum dots as a potential sensitive fluorescent probe for quercetin detection and cell imaging

A simple fluorescent quenching probe based on polyethylene glycol-400 capped sulfur quantum dots (PEG-SQDs) was fabricated to determine quercetin (QT) quantitatively. As anticipated, the PEG-SQDs exhibited favourable luminescent properties, stability and low cytotoxicity. QT effectively quenched the fluorescence of the PEG-SQDs through static quenching and the inner filter effect. Moreover, the PEG-SQDs showed rapid QT detection within a linear range of 0.100–45.0 μM, with a limit of detection of 0.014 μM (3σ/k). This fluorescent probe successfully detected QT in human serum, quercetin supplement capsules and red wine, achieving a standard recovery of 92.6 %–105 %.

Quercetin Prevents Hypertension in Dahl Salt-sensitive Rats F ed a High-salt Diet Through Balancing Endothelial Nitric Oxide Synthase and Sirtuin 1.

A high-salt diet is a leading dietary risk factor for elevated blood pressure and cardiovascular disease. Quercetin reportedly exhibits cardioprotective and antihypertensive therapeutic effects. The objective of this study is to examine the effect of quercetin on high-salt dietinduced elevated blood pressure in Dahl salt-sensitive (SS) rats and determine the underlying molecular mechanism. Rats of the Dahl SS and control SS-13 BN strains were separated into five groups, SS-13 BN rats fed a low-salt diet (BL group), SS-13 BN rats fed a high-salt diet (BH group), Dahl SS rats fed a low-salt diet (SL group), Dahl SS rats fed a high-salt diet (SH group), and SH rats treated with quercetin (SHQ group). Blood pressure was checked three weeks into the course of treatment, and biochemical markers in the urine and serum were examined. Additionally, western blot was done to evaluate the sirtuin 1 (SIRT1) and endothelial nitric oxide synthase (eNOS) expression levels. Immunohistochemical analysis was performed to verify SIRT1 levels. We demonstrated that a high-salt diet elevated blood pressure in both SS-13 BN and Dahl SS rats, and quercetin supplementation alleviated the altered blood pressure. Compared with the SH group, quercetin significantly elevated the protein expression of SIRT1 and eNOS. Immunohistochemistry results further confirmed that quercetin could improve the protein expression of SIRT1. Quercetin reduced blood pressure by enhancing the expression of SIRT1 and eNOS in Dahl SS rats fed a high-salt diet.

Dry-feed Added Quercetin Mitigates Cyclophosphamide-induced Oxidative Stress, Inflammation and Gonadal Fibrosis in Adult Male Rats.

Cyclophosphamide (CYP), a widely used cancer chemotherapeutic agent has been linked with male gonadotoxicity, resulting in infertility. The notion that potent antioxidants could be beneficial in mitigating CYP-induced gonadotoxicity necessitated this research. Therefore, we examined the effects of feed-added quercetin on CYP-induced gon-adotoxicity in male rats. Male postpubertal rats were randomly assigned into six groups of 10 rats each. The normal control (fed standard rodent diet) and two groups fed quercetin-supplemented diet at 100 and 200 mg/kg of feed received normal saline intraperitoneally at 2 ml/kg daily. A fourth group which served as the CYP control (fed standard rodent diet) and the last two groups fed quercetin at 100 and 200 mg/kg of feed were administered CYP at 150 mg/kg/day. Rats were administered normal saline or CYP intraperitoneally on days 1 and 2, while standard diet or feed-added quercetin was administered daily for 21 days. On day 22, half of the animals were either sacrificed or paired with age-matched females for fertility assessment. Estimation of testosterone levels, antioxidant, anti-inflammatory markers, and histomorphological exami-nation of the testis and epididymis was also assessed. The administration of CYP was associated with weight loss, decreased food intake, decreased antioxidant capacity, increased gonadosomatic index, increased lipid peroxidation, sub-fertility, and histological evidence of gonadal injury. However, administration of querce-tin reversed CYP-induced changes. The result of this study suggests that dietary quercetin supplementation has the ability to mitigate CYP induced gonadotoxicity and mitigate subfertility in male rats. How-ever, further studies are required to assess its possible use in humans.

Refining the Rab7-V1G1 axis to mitigate iron deposition: Protective effects of quercetin in alcoholic liver disease

Iron overload is a common feature of alcoholic liver disease (ALD) and contributes significantly to disease progression. Quercetin, a flavonoid known for its iron-chelating properties, has emerged as a potential protective compound against ALD. However, research on quercetin's regulatory effects on iron levels in ALD is limited. To address this, we conducted a study using male C57BL/6J mice were subjected to a Lieber De Carli liquid diet containing ethanol (28% energy replacement) with or without quercetin supplementation (100 mg/kg.BW) for 12 weeks. Additionally, HepG2 cells, after transfection with the CYP2E1 plasmid, were incubated with ethanol and/or quercetin. Our findings revealed that ethanol consumption led to iron overload in both hepatocytes and lysosomes. Interestingly, despite the increase in iron levels, cells exhibited impaired iron utilization, disrupting normal iron metabolism. Further analysis identified a potential mechanism involving the Rab7-V1G1 (V-ATPase subunit) axis. Inhibition of V-ATPase by Concanamycin A caused elevated ROS levels, impaired lysosomal and mitochondria function, and increased expression of HIF1α and IRP2. Ultimately, this disruption in cellular processes led to iron overload and mitochondrial iron deficiency. Quercetin supplementation mitigated ethanol-induced hepatocyte damage by reversing iron overload through modulation of the Rab7-V1G1 axis and improving the interaction between lysosomes and mitochondria. In conclusion, this study elucidates a novel pathophysiological mechanism by which quercetin protects against ALD through its regulation of iron homeostasis.

Quercetin Intake and Absolute Telomere Length in Patients with Type 2 Diabetes Mellitus: Novel Findings from a Randomized Controlled Before-and-After Study.

Telomeres, the protective chromosomal ends, progressively shorten and potentially are implicated in the pathogenesis of age-related diseases. In type 2 diabetes (T2DM), telomere shortening may play an important role, but the whole 'picture' remains limited. From a therapeutic perspective, the phytonutrient quercetin appears to be clinically effective and safe for patients with T2DM. Considering the above, we aimed to examine whether quercetin could interfere with telomere length (TL) dynamics. One hundred patients with T2DM on non-insulin medications registered within a primary healthcare facility were stratified by age and sex and randomly assigned to either standard care or standard care plus quercetin (500 mg/day) for 12 weeks, succeeded by an 8-week washout period and another 12 weeks of supplementation. Of the 88 patients completing the trial, 82 consented to blood sampling for TL measurements. Health assessments and whole blood absolute TL measurements using quantitative polymerase chain reaction (qPCR) were conducted at baseline and study end, and the findings of this subcohort are presented. Quercetin supplementation was associated with a significant increase in mean TL (odds ratio ≥ 2.44; p < 0.05) with a strengthened association after full adjustment for potential confounders through multiple logistic regression analysis (odds ratio = 3.48; p = 0.026), suggesting it as a potentially promising supplementation option. Further studies are needed to confirm this finding, elucidating the underlying molecular mechanisms of quercetin.

Quercetin Supplementation Improves Intestinal Digestive and Absorptive Functions and Microbiota in Rats Fed Protein-Oxidized Soybean Meal: Transcriptomics and Microbiomics Insights.

To clarify the nutritional mechanisms of quercetin mitigation in the digestive and absorptive functions in rats fed protein-oxidized soybean meal, 48 three-week-old male SD rats were randomly allocated into a 2 × 2 factorial design with two soybean meal types (fresh soybean meal or protein-oxidized soybean meal) and two quercetin levels (0 or 400 mg/kg) for a 28-day feeding trial. The protein-oxidized soybean meal treatment decreased (p < 0.05) the relative weights of the pancreas, stomach, and cecum, duodenal villus height, pancreatic and jejunal lipase activities, apparent ileal digestibility of amino acids, and apparent total tract digestibility of dry matter, crude protein, and ether extract. The supplementation of quercetin in the protein-oxidized soybean meal diet reversed (p < 0.05) the decreases in the duodenal length, ileal villus height, lipase activity, apparent ileal digestibility of amino acids, and apparent total tract digestibility of dry matter, crude protein, and ether extract. Transcriptomics revealed that the "alanine transport" and "lipid digestion and absorption" pathways were downregulated by the protein-oxidized soybean meal compared with fresh soybean meal, while the "basic amino acid transmembrane transporter activity" and "lipid digestion and absorption" pathways were upregulated by the quercetin supplementation. Microbiomics revealed that the protein-oxidized soybean meal increased the protein-degrading and inflammation-triggering bacteria in the cecum, while the relative abundances of beneficial bacteria were elevated by the quercetin supplementation.

Role of Quercetin in DNA Repair: Possible Target to Combat Drug Resistance in Diabetes.

Diabetes Mellitus (DM) is referred to as hyperglycemia in either fasting or postprandial phases. Oxidative stress, which is defined by an excessive amount of reactive oxygen species (ROS) production, increased exposure to external stress, and an excessive amount of the cellular defense system against them, results in cellular damage. Increased DNA damage is one of the main causes of genomic instability, and genetic changes are an underlying factor in the emergence of cancer. Through covalent connections with DNA and proteins, quercetin has been demonstrated to offer protection against the creation of oxidative DNA damage. It has been found that quercetin shields DNA from possible oxidative stress-related harm by reducing the production of ROS. Therefore, Quercetin helps to lessen DNA damage and improve the ability of DNA repair mechanisms. This review mainly focuses on the role of quercetin in repairing DNA damage and compensating for drug resistance in diabetic patients. Data on the target topic was obtained from major scientific databases, including SpringerLink, Web of Science, Google Scholar, Medline Plus, PubMed, Science Direct, and Elsevier. In preclinical studies, quercetin guards against DNA deterioration by regulating the degree of lipid peroxidation and enhancing the antioxidant defense system. By reactivating antioxidant enzymes, decreasing ROS levels, and decreasing the levels of 8-hydroxydeoxyguanosine, Quercetin protects DNA from oxidative damage. In clinical studies, it was found that quercetin supplementation was related to increased antioxidant capacity and decreased risk of type 2 diabetes mellitus in the experimental group as compared to the placebo group. It is concluded that quercetin has a significant role in DNA repair in order to overcome drug resistance in diabetes.

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.

Quercetin in semen extender curtails reactive oxygen and nitrogen species and improves functional attributes of cryopreserved buck semen

Cryopreservation of goat spermatozoa is challenging due to several factors, including one of the most essential, i.e., oxidative stress. It is particularly essential in goat semen due to its scanty ejaculate volume and high sperm concentration. This leaves a narrow sperm-to-seminal plasma ratio owing to marginal antioxidant support; moreover, semen extension further dilutes the antioxidant level, leading to an imbalance of oxidant-antioxidant equilibrium. The present study aimed to evaluate the effect of quercetin on curtailing oxidative stress and its reflection on the post-thaw survivability and membrane integrity of goat spermatozoa. For this study, six bucks were selected. Six ejaculates from each buck totaling 36 ejaculates were collected, which were then split into five parts; furthermore, each part was added with a semen extender having a particular concentration of additive. Group C without quercetin and T1 containing Vitamin E at 3 mmol/mL were considered the control and positive control respectively, whereas T2, T3, and T4 contain 10, 20, and 30 μmol/mL of Quercetin respectively. The final sperm concentration of each group was kept at 200 × 106 spermatozoa/mL. All groups were subjected to equilibration at 4 °C for 4 h, then filled in French mini (0.25 mL) straws, followed by sealing and cryopreservation. Samples after 72 h of cryopreservation were subjected to evaluation of plasma membrane integrity and viability through staining, acrosomal integrity, and mitochondrial membrane activity through flow cytometry. Evaluation of sperm kinematics as well as the oxidant-antioxidant status of sperm (ROS and nitric oxide) and seminal plasma (SOD, CAT, GPx, FRAP, and lipid peroxidation through MDA estimation) were also carried out. Quercetin, when supplemented at 20 μmol/mL in buck semen extender, significantly (p < 0.01) improved cryopreserved sperm functions in terms of plasma membrane integrity, viability, acrosomal integrity, mitochondrial membrane activity, and sperm kinematics of buck semen. Similarly, Quercetin supplementation at 20 μmol/mL significantly reduced reactive oxygen and nitrogen species (RONS) in sperm and improved the antioxidant status of seminal plasma, which was indicated by reduced oxidative damage and improved the antioxidant status of buck semen. In conclusion, Quercetin at 20 μmol/mL reduced oxidative stress, improved semen antioxidant status, and improved sperm membranes integrity and kinematics.

Effects of Micellar Quercetin Supplementation on Growth Performance, Nutrient Digestibility, Fecal Microbiota, Meat Quality, and Physiological Status in Broiler Chickens.

This study investigated the impacts of micellar quercetin (MQ) supplementation on growth performance, meat stability, excreta gas emissions, and physiological status. During a 35-day trial, 640 Ross 308 broilers were utilized. These birds were one day old, with an average initial body weight of 43.34 ± 1.43 g. They were randomly distributed across four experimental diets, each consisting of 10 replicate pens with 16 chicks per pen. The diets included the following: control (CON) with 0% micellar quercetin (MQ), TRT1 with 0.025% MQ, TRT2 with 0.050% MQ, and TRT3 with 0.100% MQ. The results indicate that broilers fed diets with increasing levels of MQ exhibited significantly higher body weight gains (BWGs) compared to the control group (p < 0.05). There was a clear linear increase in the breast muscle percentage with higher levels of quercetin supplementation (p < 0.05), while the breast color remained consistent across all groups (p > 0.05). Both cooking loss and drip loss exhibited a linear decrease as MQ levels in the diet increased (p < 0.05). The level of aspartate aminotransferase (AST) tended to decrease with higher MQ levels. Thyroxine (T4) and lymphocyte levels also showed a linear increase with increasing MQ dosage in the diet (p < 0.05). However, no significant effects were observed on nutrient digestibility, gas emissions, or fecal microbial components (Lactobacillus, E. coli, and Salmonella) with higher levels of MQ supplementation (p > 0.05). In conclusion, augmenting quercetin levels in the diet positively influenced the BWG, breast muscle development, and meat quality parameters such as cooking loss and drip loss, with beneficial effects on blood profiles.

Effect of Ergothineine and Quercetin Additions in to the In Vitro Embriyo Development

Aim: This study aimed to investigate the effects of ergothioneine and quercetin on the in vitro development of bovine embryos Materials and Methods: Cumulus-oocyte complexes (COCs) were collected via ovary aspiration from a local abattoir and cultured in vitro for maturation. After maturation, in vitro fertilization was performed. The pronuclear embryos were divided into three groups: control, 10 μM L-ergothioneine, and 10 μM quercetin supplemented. After the addition of antioxidants to the CR1aa medium, in vitro culture of embryos were performed. The cleavage and morula rates were assessed on days 2 and 5, respectively. Blastocyst formation and quality were assessed on days 7-8. Results: Statistical analysis showed cleavage and morula rates were significantly higher in the ergothioneine group compared to the quercetin and control groups (P&lt;0.05). While no blastocysts formed in the quercetin group, the blastocyst rate reached to 17.96% with ergothioneine supplementation on day 8. Conclusion: In conclusion, supplementation with 10 μM ergothioneine enhanced the in vitro development of bovine oocytes. However, 10 μM quercetin supplementation impaired development, and no blastocyst formation observed. Further studies utilizing different concentrations are warranted to better understand the effects. This study provides insights into modulating oxidative stress during in vitro embryonic production.

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

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

Investigation of potential effects of quercetin on COVID-19 treatment: a systematic review of randomized controlled trials

Objectives: The COVID-19 pandemic has rapidly become a global health crisis. Currently, there are no proven, reliable, specific treatments for COVID-19. Alongside drug interventions, supportive treatments are implemented during the disease. Quercetin, recognized for its antiviral, anti-inflammatory, anti-aging, and antioxidant properties, is under evaluation in this study for its potential impact on preventing, influencing the course, and mitigating the severity of COVID-19. Methods: A thorough search was conducted across scientific databases, including PubMed, Embase, Web of Science, SAGEpub, Copernicus, Cochrane Library, ScienceDirect, Elsevier, Scopus, Google Scholar, EBSCOhost, Crossref, Ovid-LWW, and DergiPark databases, between 1 November 2021 and 1 April 2022 to ensure a comprehensive inclusion of relevant studies. Results: Thirteen randomized controlled clinical trials (five published, eight unpublished) were identified. Existing literature supports quercetin’s role as a potent free radical scavenger with robust antioxidant properties. It exhibits anti-inflammatory characteristics by inhibiting lipid peroxidation and restraining pro-inflammatory enzymes such as lipoxygenase and phospholipase A2. Scholarly discourse suggests that quercetin supplementation within the 500-1500 mg range leads to favorable outcomes, including quicker patient discharge, reduced inflammation, increased respiratory rate, accelerated viral clearance, and an improved disease prognosis. However, it is noted that intervention durations vary across studies. Conclusions: The analysis of the studies suggested that quercetin is a promising therapeutic agent that can cause a decrease in disease symptoms, frequency of hospitalization, hospital stay, need for non-invasive oxygen treatment, need for intensive care, and mortality. Nonetheless, more clinical studies are needed to better understand quercetin’s curative effects on COVID-19 infection.

Supplementation of the Combination of Quercetin and Vitamin E Alleviates the Effects of Heat Stress on the Uterine Function and Hormone Synthesis in Laying Hens.

Chickens are sensitive to heat stress because their capacity to dissipate body heat is low. Hence, in chickens, excessive ambient temperature negatively influences their reproductive performance and health. Heat stress induces inflammation and oxidative stress, thereby rendering many reproductive organs dysfunctional. In this study, we evaluated the effects of the supplementation of dietary quercetin and vitamin E on the uterine function, eggshell quality via estrogen concentration, calcium metabolism, and antioxidant status of the uterus of laying hens under heat stress. The ambient temperature transformation was set at 34 ± 2 °C for 8 h/d (9:00 am-5:00 pm), which was followed by 22 °C to 28 °C for 16 h/d. Throughout the experiment, the relative humidity in the chicken's pen was at 50 to 65%. A total of 400 Tianfu breeder hens (120-days-old) were randomly divided into four dietary experimental groups, including basal diet (Control); basal diet + 0.4 g/kg quercetin; basal diet + 0.2 g/kg vitamin E; and basal diet + the combination of quercetin (0.4 g/kg) and vitamin E (0.2 g/kg). The results show that the combination of quercetin and vitamin E significantly increased the serum alkaline phosphatase levels and the antioxidant status of the uterus (p < 0.05). In addition, the combination of quercetin and vitamin E significantly increased the concentrations of serum estrogen and progesterone, as well as elevated the expression of hypothalamic gonadotropin-releasing hormone-1 and follicular cytochrome P450 family 19 subfamily A member-1 (p < 0.05). We also found that the calcium levels of the serum and uterus were significantly increased by the synergistic effects of quercetin and vitamin E (p < 0.05), and they also increased the expression of Ca2+-ATPase and the mRNA expression of calcium-binding-related genes in the uterus (p < 0.05). These results are consistent with the increased eggshell quality of the laying hens under heat stress. Further, the combination of quercetin and vitamin E significantly increased the uterine morphological characteristics, such as the height of the uterine mucosal fold and the length of the uterine mucosa villus of the heat-stressed laying hens. These results collectively improve the uterine function, serum and uterine calcium concentration, eggshell strength, and eggshell thickness (p < 0.05) in heat-stressed laying hens. Taken together, we demonstrated in the present study that supplementing the combination of dietary quercetin and vitamin E alleviated the effects of heat stress and improved calcium metabolism, hormone synthesis, and uterine function in the heat-stressed laying hens. Thus, the supplementation of the combination of quercetin and vitamin E alleviates oxidative stress in the eggshell gland of heat-stressed laying hens, thereby promoting calcium concentration in the serum and eggshell gland, etc., in laying hens. Hence, the combination of quercetin and vitamin E promotes the reproductive performance of the laying hens under heat stress and can also be used as a potent anti-stressor in laying hens.

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

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. 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. 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.

Quercetin in semen extender improves frozen-thawed spermatozoa quality and in-vivo fertility in crossbred Kamori goats.

This study investigated the antioxidant effect of quercetin-treated semen on frozen-thawed spermatozoa quality and in-vivo fertility in crossbred Kamori goats. In total, 32 ejaculates from four fertile bucks were diluted in Tris-based egg yolk extender with varying levels of quercetin (0, 1, 5, 10, and 15 μM). Qualified semen samples were pooled and frozen in French straws. The results revealed that the addition of quercetin in the semen extender increased (p < 0.05) frozen-thawed sperm total motility (TM), progressive motility (PM), rapid velocity (RV), average path velocity (VAP), straight line velocity (VSL), curvilinear velocity (VCL), and amplitude of lateral head (ALH) displacement in contrast to the control group. Quercetin supplementation had no effect on beat cross frequency (BCF), straightness (STR), and linearity (LIN) (p > 0.05). Quercetin showed significantly higher (p < 0.05) plasma membrane and acrosome integrity and viability (p < 0.05) of spermatozoa in contrast to the control group. Quercetin in the semen extender significantly increased (p < 0.05) superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and total antioxidant capacity (TAC) levels while reduced (p < 0.05) the contents of total oxidant status (TOS) and malondialdehyde (MDA), which were in contrast to the control group. Ultrasound results revealed that 24 out of 30 (80%) goats were found pregnant when semen was treated with 5 μM quercetin while the control group showed 18 out of 30 (60%) animals were pregnant. Thus, the study concluded that 5 μM quercetin-treated semen was found to be efficient, showed increased antioxidant status, and reduced oxidant production, leading to improved spermatozoa quality and in-vivo fertility in goats.

Quercetin decreases fructose drinking in model of fructose-induced insulin resistance. Unexpected uric acid and TBARS lowering effect of methyl cellulose vehicle and fructose combination.

The aim of this study was to improve insulin sensitivity in fructose-treated animals by ingestion of flavonoid quercetin. Several signs of insulin resistance have been developed in rats by drinking 10% fructose solution for 9 weeks. The effect of 6-week-gavage-administrated quercetin (20 mg/kg/day in 1% methyl cellulose solution) was monitored. Rats of the control groups received methyl cellulose vehicle as well. The most striking result of the quercetin treatment was the normalization of the fructose solution drinking to the level of drinking water intake. In addition, quercetin supplementation considerably decreased the plasma glucose and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) index in rats consuming fructose. Surprisingly, fructose ingestion did not elevate plasma uric acid, thiobarbituric acid reactive substances, nitrotyrosine, or advanced glycation end products fluorescence. Instead, a reduction of the above parameters was observed. In summary, these results indicate that quercetin supplementation reduces fructose drinking and decreases plasma glucose and the HOMA-IR index. Furthermore, methyl cellulose, in combination with fructose, causes uric acid - lowering, antioxidant and anti-glycation effects. Thus, methyl cellulose possibly shifts fructose metabolism in favor of the utilization of antioxidant features of fructose. Our results call for using methyl cellulose in sweetened beverages and other sweetened food.