Doses Of Quercetin Research Articles

Exploring the anti-depressant effects and nitric oxide modulation of quercetin: A preclinical study in Socially Isolated mice

Objectives This study investigates the effects of quercetin, an antioxidant and nitric oxide (NO) modulator, on depressive-like behaviours triggered by social isolation stress (SIS) in mice. SIS, known to harm psychosocial functioning and increase the risk of depression, involves oxidative stress and NO in its pathophysiology. Methods 72 male mice were divided into nine groups, including the social (SC) group as the control group (stress-free with normal saline intake). The isolation (IC) groups received normal saline, quercetin at doses of 10, 20, and 40 mg/kg, the nitric oxide synthetase inhibitor L-NAME at a dose of 5 mg/kg, the NO precursor L-arginine at a dose of 100 mg/kg, an ineffective dose of quercetin combined with L-NAME and an effective dose of quercetin combined with L-arginine. Behavioural tests (open-field, forced swimming, and splash tests) were conducted, followed by measuring hippocampal nitrite levels. Results Quercetin significantly reduced immobility in the forced swimming test, increased activity in the open-field test, and enhanced grooming behaviour, particularly at 40 mg/kg. Co-administration of an ineffective dose of quercetin (10 mg/kg) with L-NAME increased immobility and grooming activity time. Interestingly, co-administration of the effective dose of quercetin (40 mg/kg) with L-arginine increased immobility time in the FST. Additionally, administration of quercetin at doses of 20 and 40 mg/kg significantly reduced the nitrite level in the hippocampus of SIS mice. Furthermore, co-administration of L-NAME and L-arginine with ineffective and effective doses of quercetin decreased and increased nitrite levels in the hippocampus and increased immobility time in the FST compared to their respective counterparts administered alone. Conclusions These results suggest quercetin’s potential in alleviating depression by modulating NO levels, pointing to its promise in treating depression associated with chronic stressors like social isolation.

Quercetin ameliorates depressive-like phenotypes and memory deficits in hypoxia-induced murine model of stress

BackgroundHypoxia is believed to induce a form of stress that contributes to the exacerbation of certain disease conditions such as heart diseases. Most of these conditions revolve around the central nervous system (CNS) since the brain consumes a significant percentage of oxygen. PurposeThis study aims to determine the specific effect of hypoxia on mood and cognitive behaviours using behavioural assessment and histological methods in mice. Additionally, this study investigated the counter effect of quercetin (QCN) on the hypoxia-induced changes. MethodsA total of thirty (30) mice were equally divided into five (5) groups. Group 1 and 2 received 5 % DMSO while only the latter was subjected to the hypoxia protocol. Groups 3–5 received graded doses of quercetin (10, 20 and 40 mg/kg), respectively. Approximately 24 h after a consecutive seven-day treatment, the mice were tested for depressive-like symptoms as well as dysfunctional memory function using recognized pharmacological tests. Afterwards, histology of specific brain regions was conducted. Finally, the data were analysed by one-way ANOVA and statistical significance was set at p<0.05. ResultsIn comparison with the normal control, mice of the model control group scored significantly (p<0.05) higher in the tests that assess depression and significantly (p<0.05) lower in the tests that assessed memory function, both indicators of adverse effects of hypoxia. Also, the contributing brain regions were also negatively affected by hypoxia. However, a significant attenuation of these effects was observed in the groups that received quercetin. ConclusionIn conclusion, quercetin is a nutritional flavonoid that possesses the ability to improve behaviour and cognition in individuals regularly exposed to hypoxia or suffering from conditions that affect oxygen delivery within the body.

Quercetin and Thyroid.

Quercetin is the most abundant flavonoid present in fruits and vegetables. For its antiproliferative, antiviral, anti-inflammatory and antioxidants activities, it is an active ingredient of several herbal remedies and is available as a nutraceutical. Experimental studies performed in vitro have demonstrated that quercetin inhibits growth and function in normal thyroid cells and may act as a thyroid disruptor. These effects have also been confirmed in vivo using rodent models. Some studies have reported the ability of quercetin to interfere with the metabolism of thyroid hormones, since it inhibits the 5'-deiodinase type 1 (D1) activity in the thyroid, as well as in the liver. Besides the effects on normal thyroid cells, several experiments performed in vitro have shown a potential therapeutic role of quercetin in thyroid cancer. Indeed, quercetin inhibits the growth, the adhesion and the migration of thyroid cancer cells, and it also has redifferentiation properties in some thyroid cancer cell lines. In conclusion, these data suggest that, although its effects can be of benefit in hyperthyroidism and thyroid cancer, caution is required in the use of high doses of quercetin due to its anti-thyroid properties. Further in vivo studies are certainly needed to confirm these hypotheses.

Quercetin activates autophagy in the distal ischemic area of random skin flaps through Beclin1 to enhance the adaptability to energy deficiency

Random flaps are frequently employed in treating substantial skin abnormalities and in surgical tissue-rebuilding interventions. The random flap technique provides flaps of specific dimensions and contours to fit the surgical incision. However, blood supply deficiency and subsequent ischemia-reperfusion injury can cause severe oxidative stress and apoptosis, eventually leading to distal necrosis, which limits the clinical application of the flap. Quercetin (QUE) is primarily found in the glycoside form in many plant parts, such as stem bark, flowers, leaves, buds, seeds, and fruits. Cellular, animal, and clinical studies have demonstrated the antioxidant, anti-apoptosis, anti-inflammatory, and activation of autophagy properties of QUE. In previous studies, high doses of QUE effectively suppressed the survival of human umbilical vein endothelial cells (HUVECs) stimulated by hydrogen peroxide. However, different concentration gradients of QUE on HUVECs revealed a significant protective effect at a concentration of 10 mM. The protective impact of QUE on HUVECs was evaluated using scratch tests, CCK-8 assays, and EDU assays. Simultaneously, a mouse model of random skin flap was created, and the impact of QUE on skin flap survival was examined by intragastric injection. The QUE group showed a significantly larger survival area of the random flap and higher blood flow intensity compared to the control group. Furthermore, the beneficial effects of QUE were reversed by the autophagy inhibitor 3-MA. Therefore, autophagy plays a significant role in the therapeutic benefits of QUE on flap survival.

Multimodal applications of green carbon dots derived from Potentilla indica (mock strawberry): Antioxidant, antimicrobial, and quenching based quercetin sensor

This study utilized a simple hydrothermal technique to synthesize negatively charged carbon dots from Potentilla indica fruit (MSTCDs) with antioxidant and broad-spectrum antimicrobial properties, as well as a specific capacity to detect quercetin. The characterization of MSTCDs was performed using spectrophotometry (UV–vis, fluorescence, X-ray photoelectron, and Fourier-transform infrared), zeta potential, and transmission electron microscopy. The prepared MSTCDs had an average size of 8 ± 0.22 nm and zeta potential of −21 mV. The prepared MSTCDs showed negligible cytotoxicity and were found to be biocompatible with human microglial cells. MSTCDs used the static quenching and inner filter effect as their two sensing mechanisms to detect quercetin. The fluorescence intensity of the MSTCDs decreased as the dose of quercetin increased, showing a linear correlation within the dose range of 0.01–70 μM (R2 = 0.9980) and the lowest detection limit of 2 nM. The prepared MSTCDs were applied to detect quercetin in the orange and grape juice, yielding values of 3.27 and 7.04 μM, respectively. Further, the MSTCDs displayed antioxidant activity by scavenging 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl, and hydroxyl radicals, with an EC50 value of 9.3, 140.82, and 187.91 µg/mL, respectively. The antiradical activity of MSTCDs was slightly lower than the ascorbic acid except for ABTS radicals, where MSTCDs showed superior scavenging ability (EC50 = 9.3 µg/mL) compared to the control (EC50 = 33.7 µg/mL). MSTCDs exhibited dose-dependent antimicrobial activity against fungi, Gram-negative bacteria, and Gram-positive bacteria. Thus, the developed CDs showed potential as antioxidant, antimicrobial, and quenching-based quercetin sensor.

Efficacy of Different Doses of Quercetin against Chemically Induced Oral Squamous Cell Carcinoma in Hamsters

Abstract Background: The use of Caspase-3 to evaluate the chemopreventive effect of quercetin on experimentally induced squamous cell carcinoma was applied in the current study. Materials and Methods: Five groups of Syrian male hamsters were employed in the study. Group I (negative control): 5 animals do not receive any treatment. Group II: 5 animals receiving (quercetin only at a concentration of 150 mg/kg). Group III (dimethylbenz(a)anthracene [DMBA]-treated group for 14 weeks): 10 animals were coated with 0.5% DMBA. Group IV (DMBA + quercetin 150 mg/kg): 15 animals receiving quercetin of a concentration (150 mg/kg) every day through a gavage tube along with painting the hamster buccal pouch with DMBA (0.5%) three times per week for 14 weeks. Group V (DMBA + quercetin 50 mg/kg): 15 animals receiving quercetin of concentration (50 mg/kg) every day through a gavage tube along with painting the hamster buccal pouch with DMBA (0.5%) for 14 weeks at three times each week. Results: Group III showed the lowest mean area percent (10.23), whereas Group V revealed the highest mean area percent value (23.64). All groups showed a statistically significant difference among them. Conclusion: Quercetin showed apoptotic potential validated by Caspase-3, so it may be a valuable chemopreventive agent antagonizing DMBA-induced carcinogenesis in animal models.

Use of kersetin and fisetin flavonoids in combination with pregabalin and gabapentin in the treatment of neuropathic pain.

We purposed to explore the consequences of the use quercetin and fisetin alone and in combination with pregabalin and gabapentin, which are used in the management of neuropathic pain, and on neuropathic pain in general. The anti-allodynic effect of various doses (5, 10, and 20 mg/kg) of quercetin and fisetin, both singly and in combination with pregabalin and gabapentin, was evaluated by developing a neuropathic pain model induced by chronic constrictive nerve damage in rats. The effectiveness of these flavonoids was investigated by combining them with gabapentin (50 mg/kg) and pregabalin (15 mg/kg), choosing the effectual dose of 10 mg/kg and the dose of 5 mg/kg, which did not show significant antiallodynic effects. In groups combined with gabapentin and pregabalin, it was determined that they showed a significant antiallodynic effect compared with 50 mg/kg gabapentin and 15 mg/kg pregabalin. In conclusion, in our combination studies, it was observed that the effectiveness of gabapentin and pregabalin, was increased and the duration of effect was prolonged when used with lower doses of flavonoids. Based on these findings; it is possible to say that quercetin and fisetin are potential agents that can be used alone or in combination with other effective treatments to alleviate neuropathic pain.

Antibacterial Properties of Bacterial Cellulose-Quercetin Composite Membrane

Bacterial cellulose has been thoroughly explored as a biomaterial for various applications due to its intrinsic mechanical, physical, and biological features. Its structural characteristics provide ideal conditions for developing composite, expanding its range of applications even further. The current study aims to synthesize quercetin-loaded bacterial cellulose composite as a potential wound dressing by utilizing the antibacterial activity of quercetin and the unique characteristics of bacterial cellulose. The produced bacterial cellulose was ex-situ modified with quercetin. The composite was characterized for its functional group by FTIR, its morphology by FE-SEM, and its antibacterial activity was evaluated against Gram-positive S. aureus and Gram-negative E. coli through the disc diffusion method. Characterization analyses confirmed the successful impregnation of quercetin into the BC matrix. The antibacterial activity of BC-Quercetin showed moderate activity, both against S. aureus and E. coli. Determining the loading dose of quercetin into bacterial cellulose is a gap for conducting future research. However, this study indicates that combining bacterial cellulose with quercetin could provide a base for developing promising alternatives for the conventional dressing system in wound healing.

Dietary supplementation with quercetin: an ideal approach for improving meat quality and oxidative stability of broiler chickens

This study aimed to improve the eating quality of yellow-feathered broiler chicks by feeding them corn-soybean meal diets supplemented with 250, 500, and 1,000 mg/kg quercetin. we examined the impact of varying doses of dietary quercetin on the sensory quality of chicken breast meat as well as on the antioxidant enzymes, antioxidant-related signaling molecules, structure and thermal stability of myofibrillar protein (MPs), and microstructure of myogenic fibers in the meat during 24 h of postslaughter aging. Additionally, we investigated the potential correlations among antioxidant capacity, MP structure, and meat quality parameters. The results indicated that dietary supplementations with 500 and 1,000 mg/kg quercetin improved the physicochemical properties and eating quality of yellow-feathered broiler chicken breast meat during 12 to 24 h postslaughter. Additionally, quercetin improved the postslaughter oxidative stress status and reduced protein and lipid oxidation levels. It also increased hydrogen bonding interactions and α-helix content during 6 to 12 h postslaughter and decreased β-sheet content during 12 to 24 h postslaughter in chicken breast MP. This resulted in improved postslaughter MP structure and thermal stability. The correlation results indicated that the enhancement of antioxidant capacity and MP structure enhanced the physicochemical and edible qualities of yellow-feathered broiler chicken breast meat. In conclusion, the current findings suggest that dietary supplementation with quercetin is an ideal approach for improving the eating quality of chicken meat, thereby broadening our understanding of theoretical and technological applications for improving the quality of chicken.

Study on the mechanism of quercetin inducing mesenchymal stem cells to differentiate into fibroblasts through TGF-β1 and IGF-1

BackgroundStem cell differentiation has opened up new avenues for disease treatment, tissue repair, and drug development in the study of regenerative medicine, and has huge application prospects. This study aimed to explore the mechanism of quercetin on the differentiation of mesenchymal stem cells (MSCs) into fibroblasts. MethodsIn this study, cell differentiation experiments and flow cytometry were used to detect the successful isolation of bone marrow MSCs from SD rats. Quercetin at 5, 10, and 20 μM was used as low, medium, and high doses to intervene in MSCs. The cell viability changes of ligament fibroblasts at 24, 48, and 72 hours after quercetin treatment were detected using a CCK-8 cell counting kit. Cell proliferative capacity was determined by flow cytometry. RT-qPCR measured the relative expression levels of TGF-β1, IGF-1, COL-Ⅰ, COL-Ⅲ, FN (fibronectin), and TNMD (Tenomodulin) in different experimental groups. Molecular docking experiments were conducted to explore the binding effect of quercetin on TGF-β1 and IGF-1 proteins. ResultsFlow cytometry verified the successful isolation of MSCs, which had high expression of CD29 and CD73, while lower expression of CD90 and CD45. Experimental results show that low and medium doses of quercetin can enhance cell proliferation, while high doses have no significant effect on cells. Detection of cell proliferation through flow cytometry yielded similar results to CCK-8. Transwell experiments have shown that low and medium doses of quercetin can increase cell migration ability. In addition, RT-qPCR detection showed that quercetin can increase the mRNA expression of TGF-β1 and IGF-1, and promote the expression of COL-Ⅰ, COL-Ⅲ, FN, and TNMD genes in ligament fibroblasts. Molecular docking results showed that quercetin can bind firmly to TGF-β1 and IGF-1. ConclusionOverall, this study revealed the morphological characteristics and identification of MSCs, as well as the regulatory mechanism of quercetin on the behavior of ligament fibroblasts. Quercetin affects the proliferation and gene expression of ligament fibroblasts by regulating the expression of TGF-β1 and IGF-1, which may provide a new perspective for biomedical research on the skeletal system.

Quercetin alleviates PM2.5-induced chronic lung injury in mice by targeting ferroptosis.

PM2.5 is a well-known harmful air pollutant that can lead to acute exacerbation and aggravation of respiratory diseases. Although ferroptosis is involves in the pathological process of pulmonary disease, the potential mechanism of ferroptosis in PM2.5-caused lung inflammation and fibrosis need to be further clarified. Quercetin is a phenolic compound that can inhibit ferroptosis in various diseases. Hence, this study explores the role of ferroptosis in lung injury induced by PM2.5 in order to further elucidate the beneficial effect of quercetin and its underlying mechanism. C57BL/6J mice were treated with either saline or PM2.5 by intratracheal instillation 20 times (once every two days). Additionally, PM2.5-treated mice were supplemented with two doses of quercetin. Lung injury, lipid peroxidation, iron content and ferroptosis marker protein expression and the Nrf2 signaling pathway were evaluated. In vitro, cell experiments were applied to verify the mechanisms underlying the links between Nrf2 signaling pathway activation and ferroptosis as well as between ferroptosis and inflammation. In vivo, PM2.5 increased lung inflammation and caused lung fibrosis and increased lipid peroxidation contents, iron contents and ferroptosis markers in lung tissues; these effects were significantly reversed by quercetin. Additionally, quercetin upregulated the nuclear Nrf2 expression and downregulated Keap1 expression in lung tissues of PM2.5-exposed mice. Quercetin decreased lipid peroxidation products, iron contents and ferroptosis levels and increased the nuclear translocation of Nrf2 and the degradation of Keap1 in PM2.5-exposed BEAS-2B cells. Moreover, we found that quercetin and dimethyl fumarate markedly decreased lipid peroxidation production and ferroptosis by activating the Nrf2-Keap1 pathway in PM2.5-exposed cells. Furthermore, quercetin reduced inflammatory cytokines and TGF-β1 in PM2.5-exposed cells. Our data suggested that Nrf2 is involved in ferroptosis in PM2.5-induced lung injury, and quercetin can alleviate these adverse effects via activating Nrf2-Keap1 signaling pathway.

Effect of dietary Achyranthes japonica extract on growth performance of growing pigs and absorption rate of quercetin in blood.

This study was done to investigate the effects of the incorporation of Achyranthes japonica extracts (AJE) in diet on the production parameters of growing pigs. Exp 1: Total, 105 crossbred pigs (average body weight: 24.47 ± 2.46 kg) were used in a 6-week feeding trial. Pigs (seven replicates, five pigs per pen) were allotted randomly to three treatments. Dietary treatments: CON (basal diet); basal diet with 0.025% AJE, and basal diet + 0.050% AJE). Growth performance, nutrient digestibility, fecal microbial count, and fecal noxious gas were assessed in this study. Average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F) were not affected by the addition of up to 0.05% AJE. In the case of apparent total tract digestibility (ATTD), dry matter (DM), nitrogen (N), and digestible energy (DE) were not changed in 3rd and 6th weeks of the feeding trial through the addition of AJE up to 0.05% in the growing pig diet. In microbial count, Lactobacillus and Escherichia coli count at 3rd and 6th week was similar in all the treatment diets. The inclusion of AJE at levels up to 0.05% in growing pig diet had no effect on the production of NH3, H2S, acetic acid, and CO2 in the feces. After ending the Exp 1, a total of nine pigs were divided into three treatment groups. Treatment diets were included, TRT1, basal diet + powder quercetin 30 g; TRT2, basal diet + powder quercetin 150 g; TRT3, basal diet + powder quercetin 300g. Rate of absorption in blood was increased with the higher dose of quercetin. The results suggested incorporation of AJE up to 0.05% has no significant effect on ADG, ADFI, and G:F, as well as DM, N, and DE digestibility, fecal microbial count, and fecal noxious gas emission in growing pigs, even though no negative effect was found.

Evaluation of the Antigenotoxic Effect of Quercetin Against Antiepileptic Drug Genotoxicity by Comet Analysis

Valproic acid (VPA) is among the most commonly used antiepileptic drugs in childhood and adult epilepsy. Although VPA is well tolerated, it can cause life-threatening side effects. VPA has toxic and genotoxic effects. Antioxidants can reverse drugs' toxic and genotoxic effects. Therefore, our study aimed to evaluate the antigenotoxic protective effect of quercetin (QUE) against VPA genotoxicity by in vitro comet assay analysis method. Comet assay analysis was performed in five different groups. Group I; negative control (Sterile H2O), Group II; positive control (H2O2), Group III; VPA was applied in four different dose ranges, Group IV; QUE was applied in four different dose ranges, Group V; For the simultaneous combined administration of VPA and QUE, three different doses of VPA + four different doses of QUE were administered. Low-dose administration of QUE was more effective in ameliorating the damage caused by low-dose VPA (62.5 μg/ml) administration. It is seen that the genotoxic damage caused by the application of 125 μg/ml VPA can be eliminated by QUE at all doses. It was determined that different doses of QUE exhibited a significant antigenotoxic effect against damage caused by 125 µg/mL VPA (P&amp;lt;0.05). In our study, the curative effect of QUE on DNA damage was determined by in vitro comet analysis. Our analysis results showed that QUE ameliorates VPA-induced genetic damage.

Influence of Quercetin Pretreatment on Pharmacokinetics of Warfarin in Rats.

Warfarin (WAR) is an anticoagulant with a narrow therapeutic index and is principally metabolized by CYP3A4 and CYP2C9 enzymes. The inhibitors of these enzymes may alter the systemic exposure to WAR. Quercetin (QUE), a bioflavonoid, may modify the bioavailability of drugs used concurrently by inhibiting CYP3A4, CYP2C8, CYP2C9, CYP1A2, and Pglycoprotein (P-gp). The current study scrutinized the influence of QUE on WAR pharmacokinetics in rats. QUE was orally administered to animals for 14 consecutive days, followed by WAR as a single oral dose on the 15th day in the pre-treatment group. The co-administration group received a single dose of QUE and WAR concomitantly. Only carboxymethylcellulose (CMC) 0.5% was administered as a vehicle to control group. In the pre-treated group, WAR's Cmax was increased by 30.43%, AUC0-∞ by 62.94%, and t1/2 by 10.54%, while Cl decreased by 41.35%, relative to control. In co-administered animals, WAR's Cmax increased by 10.98%, AUC0-∞ by 20.20%, and t1/2 by 8.87%, while Cl declined by 16.40%. QUE alters the pharmacokinetics of WAR, warranting possibly WAR dose adjustment after confirmatory clinical investigations, specifically in patients with thrombotic disorders and a pre-treatment history of QUE or its product.

Quercetin induces hepatic stellate cell apoptosis by inhibiting the PI3K/Akt signaling pathway via upregulating miR-146

To investigate whether quercetin induces apoptosis of hepatic stellate cells by regulating miR-146 to inhibit the PI3K/Akt signaling pathway. Rat hepatic stellate cells (HSC-T6) were treated with TGF-β and different concentrations (40, 60 and 80 μmol/L) of quercetin, and the changes in cell proliferation and apoptosis were detected using CCK-8 assay and flow cytometry. RT-qPCR was used to detect the expression of miR-146 and mRNA expressions of α-SMA, collagenⅠ, TRAF6, PI3K and Akt in the treated cells, and the protein expressions of α-SMA, collagenⅠ, TRAF6, PI3K, Akt and p-Akt were detected using Western blotting. Immunofluorescence assay was used to detect the protein expression of α-SMA and collagenⅠ. The effects of transfection with miR-146 mimic and inhibitor on the protein expressions of the cells were also examined using Western blotting. Treatment with quercetin dose- and time-dependently inhibited the proliferation of HSC-T6 cells and significantly increased the total cell apoptosis rate (P<0.01). TGF-β-stimulated HSC-T6 cells showed significantly increased mRNA and protein expression levels of α-SMA, collagenⅠ, TRAF6, PI3K and Akt (P<0.05), which were significantly down-regulated by quercetin treatment (P<0.05). Quercetin significantly upregulated the expression of miR-146 in HSC-T6 cells (P<0.01), Transfection of the cells with miR-146 mimic significantly decreased the mRNA and protein expression levels of α-SMA, collagen Ⅰ, TRAF6, PI3K and Akt (P<0.05), and miR- 146 inhibitor produced the opposite effects (P<0.05). Quercetin inhibits proliferation and promotes apoptosis of HSCs by upregulating miR-146 to inhibit the PI3K/Akt signaling pathway.

The monoaminergic pathways are involved in the antidepressant-like effect of quercetin.

Quercetin, a plant-derived flavonoid, is an antioxidant and has demonstrated antidepressant and anti-inflammatory activities in several animal models. However, there is scanty information on the underlying mechanisms of its antidepressant property. This present study aimed at assessing the involvement of monoaminergic systems in the antidepressant-like activity of quercetin in experimental animals. Mice received varying doses of quercetin (25, 50 &100mg/kg daily) and were then subjected to open field test (OPF), despair tests, the reserpine test, and the yohimbine lethality test (YLT). In addition, monoaminergic involvement was investigated by combining quercetin (100mg/kg) with dopaminergic antagonists (haloperidol and sulpiride), adrenergic blockers (prazosin, propranolol and yohimbine), and serotonergic blockers/inhibitors (metergoline). The results showed that quercetin produced significant anti-immobility effects in the forced swim test (FST) and tail suspension test (TST), suggesting antidepressant activity. In addition, the potentiation of yohimbine lethality by quercetin further indicates its antidepressant-like property. This antidepressant action demonstrated was, however, blocked when quercetin was co-administered with dopaminergic, adrenergic and serotonergic antagonists, suggesting involvement of the monoaminergic system in the antidepressant action of quercetin. Nevertheless, quercetin did not significantly alter the locomotor activity of mice, which implies lack of stimulant effect. Taken together, these outcomes suggest that monoaminergic systems are likely involved in the anti-depressant effect of quercetin in mice.

Modulatory role of dose-dependent quercetin supplemented diet on behavioral and anti-oxidant system in &lt;i&gt;Drosophila melanogaster&lt;/i&gt; model

Background: Quercetin is an abundant bio-flavonoid in foods having several biological activities including anti-oxidant properties. However, the toxicity of quercetin may limit its use. Therefore, screening a graded dose of quercetin may be an important step in its use as a dietary supplement. Hence, the effects of graded doses of quercetin on the survival, locomotive behavior and oxidant-antioxidant system in D. Melanogaster was investigated.Methods: A Survival assay was conducted by feeding 50 fruit flies per vial with 50-400 mg/g quercetin-diet for 14 days. For behavioral and biochemical studies, flies were divided into 4 vials (50 flies each) 0, 100, 200 and 300 mg/g quercetin-diet. Flies were treated with vehicle or quercetin for 7 days. Behavioral assessment of negative geotaxis was determined from the climbing activities of flies. Finally, flies were killed, homogenized and centrifuged for supernatant for the assay of Catalase (CAT), Superoxide dismutase (SOD), Glutathione (GSH), Malondialdehyde (MDA) and Total thiol.Results: Quercetin treated groups showed a dose-dependent significant decrease (p&lt;0.001) in survival rate. Climbing activity was unaltered at 100 mg but significantly (p&lt;0.05) reduced at 200 and 300mg quercetin. Total thiol was not significantly altered (p&gt;0.05) across the groups, MDA was reduced (p&lt;0.05) at 300 mg compared to control, CAT activity was significantly increased (p&lt;0.05) at 100-200 mg compared to control while GSH and SOD at 100-200 mg of quercetin increased.Conclusion: Quercetin showed better antioxidant activity at lower doses and adversely affected the climbing behavior and survival rate at higher doses. Therefore, quercetin use should be dose modulated and used with caution.

Influences of flavonoid (quercetin) inclusion to corn-soybean-gluten meal-based diet on broiler performance.

Quercetin (a predominant flavonoid) is considered to have antimicrobial and antioxidant properties. This trial was conducted to evaluate the impact of graded doses of quercetin (QS) on growth efficiency, nutrient retention, faecal score, footpad lesion score, tibia ash and meat quality. In a 32-day feeding test, a total of 576 1-day-old Ross 308 broilers (male) were allocated arbitrarily with an average body weight of 41 ± 0.5 g. The trial had four dietary treatments with eight repetitions of 18 birds per pen and a basal diet incorporating 0%, 0.02%, 0.04% and 0.06% of QS. As the QS dosage increased, body weight gain tended to increase linearly on Days 9-21 (p = 0.069) and overall period (p = 0.079). Similarly, feed intake increased (p = 0.009) linearly with the increasing doses of QS on Days 9-21. Likewise, there was a linear improvement in dry matter (p = 0.002) and energy (p = 0.016) digestibility after QS administration. Moreover, the inclusion of QS supplement (0%-0.06%) linearly increased (p = 0.012) tibia ash in broilers. However, the faecal score and footpad lesion score showed no significant outcome (p > 0.05). By giving broilers a graded amount of QS, the relative organ weights of breast muscle (p = 0.009) and spleen (p = 0.006) improved linearly, meat colour lightness increased (p = 0.015), redness tended to improve (p = 0.065) linearly and drip loss decreased (p = 0.015) linearly. The inclusion of QS in the graded-level diet led to improvements in growth efficiency, nutrient absorption, meat quality and tibia ash, which recommended it as a beneficial feed additive for the broiler.

Mechanism of action of buckwheat quercetin in regulating lipid metabolism and intestinal flora via Toll-like receptor 4 or nuclear factor κB pathway in rats on a high-fat diet

ObjectivesBuckwheat quercetin (QUE) was used as a dietary supplement to investigate the mechanism of QUE on the regulation of lipid metabolism and intestinal flora in hyperlipidemic rats. MethodsHere, using a high-fat diet–induced hyperlipidemia model, the intervention was carried out by gavage of QUE at doses of 50, 100, and 200 mg/kg. Serum lipid levels, liver biochemical parameters, and histopathologic changes in the liver and intestinal microorganisms were measured in rats by enzyme-linked immunosorbent assay, hematoxylin-eosin, and high-throughput sequencing, respectively. ResultsOur results found that QUE, at a dose of 200 mg/kg, significantly reduced body weight, liver index, and lipid levels in rats (P < 0.05); improved hepatic oxidative stress; and repaired liver injury. In addition, the upregulation of beneficial bacteria, such as christensenellaceae and Bifidobacterium, in the organism increased the content of short-chain fatty acids, thus interfering with intestinal pH and improving the intestinal environment, while downregulating the relative abundance of Proteobacteria and Eubacterium_coprostanoligenes_group, and regulating the overproduction of butyrate. The real-time fluorescence quantitative polymerase chain reaction results found that QUE inhibited the expression of Toll-like receptor 4 (TLR4) and nuclear factor κB (NF-κB) mRNA content and blocked the activation of the TLR4/NF-κB signaling pathway, thus affecting the downregulation of lipid levels and restoring intestinal homeostasis. ConclusionsA QUE dose of 200 mg/kg may improve lipid levels and the composition of intestinal flora through the TLR4/NF-κB pathway, suggesting that proteobacteria and christensenellaceae abundance changes may be biomarkers of potential diseases.

Quercetin flavonoid and vitamin C recuperate kidney functions in potassium bromate-induced renal dysfunction in Wistar rats.

Studies into the functions and mechanisms of action of quercetin may be able to help dispel the negative effects of toxicants on renal toxicity due to its anti-inflammatory potential, as well as provide a simple, low-cost alternative for treating renal toxicity in developing nations. Therefore, the present study evaluated the ameliorative and renal protective activities of quercetin dihydrate in potassium bromate-induced, renal-toxic Wistar rats. Forty-five (45) mature female Wistar rats (180-200 g) were randomly grouped into nine (9) (n = 5). Group A served as general control. Nephrotoxicity was induced in groups B to I with the administration of potassium bromate. While group B served as a negative control, groups C-E received graded doses of quercetin (40, 60, and 80 mg/kg, respectively). Group F received 2.5 mg/kg/day of vitamin C, while groups G-I received vitamin C (2.5 mg/kg/day) and co-administration of a graded dose of quercetin (40, 60, and 80 mg/kg, respectively). Daily urine levels and final blood samples by retro-orbital techniques were collected for GFR, urea, and creatinine level assessment. The collected data were subjected to ANOVA and Tukey's post hoc test, and the results were presented as mean SEM with a p < 0.05 level considered significant. Body and organ weight and GFR were significantly reduced (p < 0.05), while serum and urine creatinine and urea were decreased in renotoxic animals. However, treatment with QCT reversed the renotoxic effects. We, therefore, concluded that quercetin administered alone or with vitamin C conferred renal protection by reversing KBrO3-induced renal toxicity in rats. Further studies to corroborate the present findings are recommended.