Therapeutic Effect Of Quercetin Research Articles

Quercetin inhibited LPS-induced cytokine storm by interacting with the AKT1-FoxO1 and Keap1-Nrf2 signaling pathway in macrophages

Cytokine storm (CS) emerges as an exacerbated inflammatory response triggered by various factors such as pathogens and excessive immunotherapy, posing a significant threat to life if left unchecked. Quercetin, a monomer found in traditional Chinese medicine, exhibits notable anti-inflammatory and antiviral properties. This study endeavors to explore whether quercetin intervention could mitigate CS through a combination of network pharmacology analysis and experimental validation. First, common target genes and potential mechanisms affected by quercetin and CS were identified through network pharmacology, and molecular docking experiments confirmed quercetin and core targets. Subsequently, in vitro experiments of Raw264.7 cells stimulated by lipopolysaccharide (LPS) showed that quercetin could effectively inhibit the overexpression of pro-inflammatory mediators and regulate the AKT1-FoxO1 signaling pathway. At the same time, quercetin can reduce ROS through the Keap1-Nrf2 signaling pathway. In addition, in vivo studies of C57BL/6 mice injected with LPS further confirmed quercetin's inhibitory effect on CS. In conclusion, this investigation elucidated novel target genes and signaling pathways implicated in the therapeutic effects of quercetin on CS. Moreover, it provided compelling evidence supporting the efficacy of quercetin in reversing LPS-induced CS, primarily through the regulation of the AKT1-FoxO1 and Keap1-Nrf2 signaling pathways.

Quercetin Promotes Abdominal Aortic Aneurysm Regression Through the RAGE/PI3K/AKT/mTOR Axis

Objective: Abdominal aortic aneurysms (AAA) are a common critical cardiovascular disease with high morbidity and mortality rates. Quercetin, a flavonoid and a traditional Chinese medicinal ingredient commonly found in vegetables and fruits, has a favorable inhibitory effect on experimental aneurysms without side effects. This study aimed to model elastase AAA and investigate the mechanism of action of quercetin in alleviating AAA. Methods: Quercetin was administered at a dose of 60 mg/kg once daily starting on the day of AAA induction for 5 weeks. The therapeutic effect of quercetin on AAA was demonstrated using biochemical assays, observation of pathological tissue sections, Elastic Van Gieson staining, immunohistochemistry, molecular docking simulations, and Western blot protein validation. Results: Our study showed that quercetin treatment significantly alleviated abdominal aortic vessel wall dilatation, elastin degradation and adhesion to surrounding tissues caused by elastase. Additionally, quercetin significantly inhibited the mRNA and protein expression of the receptor for advanced glycation end products(RAGE)/ phosphatidylinositol 3-kinase (PI3K)/ phosphatidylinositol 3-kinase (AKT) / mammlian target of rapamycin (mTOR) pathway. Conclusion: Quercetin can alleviate abdominal aortic injury caused by elastase via RAGE/PI3K/AKT/mTOR and provide experience in clinical use.

Quercetin protects against sepsis-associated encephalopathy by inhibiting microglia-neuron crosstalk via the CXCL2/CXCR2 signaling pathway

BackgroundSepsis-associated encephalopathy (SAE) is a common brain lesion associated with severe sepsis, for which ferroptosis is a key driving factor. Thus, suppressing ferroptosis may be an effective strategy for treating SAE. Quercetin (QUE) is a natural flavonoid with antioxidant and anti-inflammatory properties. However, its role on ferroptosis in SAE remains unclear. PurposeThis study aimed to investigate the mechanism underlying the therapeutic effect of QUE on cecal ligation perforation (CLP)-induced SAE. MethodsIn vivo and in vitro SAE models were established using CLP and lipopolysaccharide (LPS), respectively. Both models underwent pre-treatment with QUE. ResultsQUE attenuated CLP-induced symptoms, including temperature changes, neurological severity scores, learning and memory dysfunction, inflammatory cytokine release, and microglia activation in SAE mice, and inhibited LPS-induced microglia recruitment and chemotaxis. Bioinformatics analysis revealed that the C-X-C motif chemokine ligand 2 (CXCL2)/C-X-C motif chemokine receptor 2 (CXCR2) axis may play a key role in QUE-mediated protection against SAE. Moreover, QUE significantly inhibited LPS-induced CXCL2 up-regulation and protein secretion from microglia. Recombinant mouse-derived CXCL2 (rmCXCL2) promoted inflammatory cytokine secretion, NF-κB/NLRP3 signaling activation, and microglia recruitment and chemotaxis. Furthermore, rmCXCL2 induced ferroptosis in mouse hippocampal neurons, as evidenced by elevated malondialdehyde levels, decreased glutathione levels, excessive iron uptake, and altered ferroptosis-related protein expression. The CXCR2 antagonist SB225002 effectively reversed the effects of rmCXCL2. Importantly, in vivo experiments further demonstrated that the therapeutic effect of QUE on SAE was inhibited by rmCXCL2. ConclusionThis study demonstrates that CXCL2 secreted by activated microglia mediates microglia self-activation and induces hippocampal neuronal ferroptosis via CXCR2 and that QUE exerts neuroprotective effects on SAE by blocking interactions between microglia and neurons via CXCL2/CXCR2 pathway inhibition.

Effects of quercetin in preclinical models of Parkinson's disease: A systematic review.

Parkinson's disease (PD) is a neurodegenerative disease that affects dopaminergic neurons, thus impairing dopaminergic signalling. Quercetin (QUE) has antioxidant and neuroprotective properties that are promising for the treatment of PD. This systematic review aimed to investigate the therapeutic effects of QUE against PD in preclinical models. The systematic search was performed in PubMed, Scopus and Web of Science. At the final screening stage, 26 articles were selected according to pre-established criteria. Selected studies used different methods for PD induction, as well as animal models. Most studies used rats (73.08%) and mice (23.08%), with 6-OHDA as the main strategy for PD induction (38.6%), followed by rotenone (30.8%). QUE was tested immersed in oil, nanosystems or in free formulations, in varied routes of administration and doses, ranging from 10 to 400 mg/kg and from 5 to 200 mg/kg in oral and intraperitoneal administrations, respectively. Overall, evidence from published data suggests a potential use of QUE as a treatment for PD, mainly through the inhibition of oxidative stress, neuroinflammatory response and apoptotic pathways.

Quercetin as a possible complementary agent for early-stage COVID-19: Concluding results of a randomized clinical trial.

Background: Quercetin, a natural polyphenol with demonstrated broad-spectrum antiviral, anti-inflammatory, and antioxidant properties, has been proposed as an adjuvant for early-stage coronavirus disease 2019 (COVID-19) infection. Objective: To explore the possible therapeutic effect of quercetin in outpatients with early-stage mild to moderate symptoms of COVID-19. Methods: This was an open-label randomized controlled clinical trial conducted at the department of medicine, King Edward Medical University, Lahore, PK. Patients were randomized to receive either standard of care (SC) plus an oral quercetin supplement (500mg Quercetin Phytosome®, 1st week, TDS: 2ndweek, BDS) (n = 50, quercetin group) or SC alone (n = 50, control group). Results: After one week of treatment, patients in the quercetin group showed a speedy recovery from COVID-19 as compared to the control group, i.e., 34 patients (vs. 12 in the control group) tested negative for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (p = 0.0004), and 26 patients (vs. 12 in the control group) had their COVID-19-associated acute symptoms resolved (p = 0.0051). Patients in the quercetin group also showed a significant fall in the serum lactate dehydrogenase (LDH) mean values i.e., from 406.56 ± 183.92 to 257.74 ± 110.73 U/L, p = 0.0001. Quercetin was well-tolerated by all the 50 patients, and no side effects were reported. Conclusion: Our results, suggest the possible therapeutic role of quercetin in early-stage COVID-19, including speedy clearance of SARS-CoV-2, early resolution of the acute symptoms and modulation of the host's hyperinflammatory response. Clinical Trial Registration: clinicaltrials.gov, identifier NCT04861298.

Quercetin protects against iron overload-induced osteoporosis through activating the Nrf2/HO-1 pathway

AimsEucommia is the tree bark of Eucommia japonica, family Eucommiaceae. In traditional Chinese medicine, Eucommia is often used to treat osteoporosis. Quercetin (QUE), a major flavonoid extract of Eucommia japonica, has been reported to have anti-osteoporosis effects. However, there are no studies reporting the mechanism of QUE in the treatment of iron overload-induced osteoporosis. This study set out to investigate the therapeutic effects of QUE against iron overload-induced bone loss and its potential molecular mechanisms. Materials and methodsIn vitro, MC3T3-E1 cells were used to study the effects of QUE on osteogenic differentiation, anti-apoptosis and anti-oxidative stress damage in an iron overload environment (FAC 200 μM). In vivo, we constructed an iron overload mouse model by injecting iron dextrose intraperitoneally and assessed the osteoprotective effects of QUE by Micro-CT and histological analysis. Key findingsIn vitro, we found that QUE increased the ALP activity of MC3T3-E1 cells in iron overload environment, promoted the formation of bone mineralized nodules and upregulated the expression of Runx2 and Osterix. In addition, QUE was able to reduce FAC-induced apoptosis and ROS production, down-regulated the expression of Caspase3 and Bax, and up-regulated the expression of Bcl-2. In further studies, we found that QUE activated the Nrf2/HO-1 signaling pathway and attenuated FAC-induced oxidative stress damage. The results of the in vivo study showed that QUE was able to reduce iron deposition induced by iron dextrose and attenuate bone loss. SignificanceOur results suggested that QUE protects against iron overload-induced osteoporosis by activating the Nrf2/HO-1 signaling pathway.

Quercetin Inhibits Pyroptosis in Diabetic Cardiomyopathy through the Nrf2 Pathway.

The present study investigated whether quercetin promotes the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) to inhibit pyroptosis progression and ameliorate diabetic cardiomyopathy. We evaluated the protective effects of quercetin against diabetic cardiomyopathy by analyzing the expression of pyroptosis pathway proteins, myocardial cell apoptosis rate, degree of myocardial fibrosis, and serum inflammatory indices in the hearts of model rats with diabetes. We evaluated the expression of Nrf2 in the nucleus of cardiomyocytes and H9C2 cells to clarify the role of quercetin in promoting the nuclear translocation of Nrf2. In addition, we coincubated cardiomyocytes with the Nrf2 inhibitor ML385 to confirm that quercetin inhibits the diabetes-induced cardiomyocyte pyroptosis via the Nrf2 pathway. We found that quercetin promoted the nuclear translocation of Nrf2 in cardiac cells of diabetic rats, increased the expression of the antioxidant proteins HO-1, GCLC, and SOD, reduced the accumulation of ROS and the degree of cardiomyocyte apoptosis, and alleviated diabetes-induced cardiac fibrosis. The therapeutic effects of quercetin were further validated in H9C2 cardiomyocytes. Interestingly, ML385 prevented the beneficial effects of quercetin on diabetic cardiomyopathy, further indicating that the quercetin-mediated inhibition of pyroptosis requires the participation of the Nrf2 pathway. In conclusion, quercetin promoted the nuclear translocation of Nrf2, increased the expression of antioxidant factors in cells, and inhibited the progression of cell pyroptosis, thereby alleviating diabetic cardiomyopathy.

Therapeutic Effect of Quercetin in Letrozole Induced Polycystic Ovary Syndrome in Rat Model

Therapeutic Effect of Quercetin in Letrozole Induced Polycystic Ovary Syndrome in Rat Model

Effect of quercetin as therapeutic and protective agent in Aluminum Chloride-induced Alzheimer's disease rats

Alzheimer's disease (AD) is a neurodegenerative disease clinically characterized by progressive cognitive impairment. This work aimed to investigate the role of quercetin (Q) in the treatment and protection of AlCl3-induced AD in rats through exploring the molecular mechanisms underlying its neuroprotective and therapeutic properties. In this study, male Wistar rats were allocated to two experiments: experiment I (therapeutic effect of quercetin) in which the rats were divided into: normal control group (C-Saline) which was induced with saline for 56 days, C-Q50 group, which was administered orally with Q (50 mg/kg) for 28 days after induction saline for 28 days, AD (AlCl3-Saline) group received AlCl3 (50 mg/kg) intraperitoneally for 28 days followed by saline for 28 days, and the AlCl3-Q50 group received Q (50 mg/kg) orally for 28 days after induction with AlCl3 for 28 days. In experiment II rats were divided into: normal control (NC) group, Q50 (50 mg/ kg) group, AlCl3 (AD) group, and AlCl3 + Q50 group which was co-administrated with AlCl3 + Q50 for 56 successive days. Dopamine (DA) and acetylcholinesterase) AChE (levels were estimated for all rat groups. The results showed that post-treatment of the AD-induced rats with Q50 as well as co-administration of AlCl3with Q50, significantly reduced the AChE level in serum, significantly increased the DA level, and significantly increased the body weight change compared to the AlCl3group, but did not show any significant change in the brain weight. We concluded that quercetin significantly improved the cholinergic and dopaminergic dysfunctions by lowering the Acetylcholine esterase level and restoring the dopamine level

Quercetin inhibits proliferation of and induces apoptosis in non-small-cell lung carcinoma via the lncRNA SNHG7/miR-34a-5p pathway

Objective To determine the role of quercetin in non-small cell lung carcinoma (NSCLC) and the biological outcomes using transfection experiments. Materials and methods Real-time reverse transcription-PCR and data collection were performed to determine lncRNA and miRNA levels. Transwell assay was performed to assess the invasion ability of cells. Apoptosis of cells digested with trypsin was determined using the Annexin V-FITC kit. Luciferase activity was determined using the luciferase reporter gene system. Cell viability was tested using the Cell Counting Kit-8 assay. A xenograft mouse model was established to investigate the effects of quercetin on tumor growth. Results The expression levels of the long non-coding RNA (lncRNA) small nucleolar RNA host gene 7 (SNHG7) were elevated in NSCLC cells, and the expression levels of the microRNA miR-34a-5p were decreased compared with those in normal cells. Further investigation revealed that quercetin decreased SNHG7 and elevated miR-34a-5p levels in NSCLC cells (p < .05). The luciferase reporter gene assay, RNA-binding protein immunoprecipitation assay, and transfection experiments revealed target-binding sequences between SNHG7 and miR-34a-5p. Overexpression of SNHG7 or miR-34a-5p inhibitor promoted NSCLC cell proliferation and accelerated tumor cell growth and metastasis. The therapeutic effect of quercetin on NSCLC cells was counteracted by co-transfection of SNHG7 mimic or miR-34a-5p inhibitor. Quercetin inhibited the survival, proliferation, migration, and invasion of NSCLC cells and enhanced their apoptosis. Using the mouse model, quercetin was shown to inhibit tumor growth. Conclusions Quercetin inhibits the proliferation and induces apoptosis of NSCLC cells by mediating signaling via the lncRNA SNHG7/miR-34a-5p pathway.

Quercetin Alleviates Intervertebral Disc Degeneration by Modulating p38 MAPK-Mediated Autophagy.

Intervertebral disc degeneration (IVDD) is a degenerative and chronic spinal disorder often associated with the older population. Oxidative stress is a major pathogenic factor of aging that results in the apoptosis of nucleus pulposus cells (NPCs) and extracellular matrix (ECM) degradation. Quercetin (QUE), a naturally occurring flavonoid with antioxidant and anti-inflammatory properties, has been studied in research on degenerative diseases. However, the potential effects and mechanisms of action of QUE on IVDD remain unclear. In this study, the effects of QUE on antiapoptosis and ECM metabolism were firstly investigated in TBHP-treated NPCs. Meanwhile, the autophagy inhibitor, 3-MA, and p38 MAPK inhibitor, SB203580, were used in subsequent TBHP-induced NPC experiments to determine whether QUE exerted its protective effects through autophagy and the p38 MAPK/mTOR signaling pathway. Finally, the therapeutic effects of QUE were confirmed in vivo using a rat tail needle puncture-induced model of IVDD. We found that QUE treatment significantly alleviated oxidative stress-decreased cell viability and intracellular ROS levels in NPCs treated with TBHP. Furthermore, treatment with QUE led to a decrease in apoptosis as measured by decreased Bax and increased Bcl-2 expression and PE/7-AAD flow cytometry analysis. QUE also promoted ECM stability as measured by increased collagen II and aggrecan and decreased MMP13 levels. Our results also showed that QUE promoted the expression of autophagy markers beclin-1, LC3-II/I, and decreased p62. Inhibition of autophagy by inhibitor 3-MA may partially reverse the protective effect of QUE on apoptosis and ECM degeneration, indicating that autophagy was involved in the protective effect of QUE in NPCs. Further study confirmed that QUE partially inhibited the p38 MAPK signaling pathway and inhibition of p38 MAPK by SB203580 activated autophagy, indicating that QUE protected NPCs against apoptosis and prevented ECM degeneration via the p38 MAPK-autophagy pathway. Finally, using a rat tail puncture-induced model of IVDD, we confirmed that QUE had a protective effect against IVDD. Our results suggest that QUE could prevent IVDD by modulating p38 MAPK-mediated autophagy and, therefore, is a potential therapeutic strategy in the treatment of IVDD.

Synthesis of a green bigel using cottonseed oil/cannabis oil/alginate/ferula gum for quercetin release: Synergistic effects for treating infertility in rats

Although therapeutic effect of quercetin (Quer) was reported on non-alcoholic fatty liver disease (NAFLD), destructive effects have been shown on male fertility due to its pro-oxidative properties. On the other hand, NAFLD impairs germ cells to produce sperm and leads to male infertility. Herein, a biocompatible and green bigel was designed for Quer delivery to prevent infertility induced by NAFLD as the increasing complications. Bigels were prepared using cottonseed oil/cannabis oil/alginate/ferula gum and optimized by the mixture design method. NAFLD was induced by 58% of dietary calorie as lard and 42 g/l fructose for 16 weeks in Sprague-Dawley rats. So on animals received 2 mg/kg Quer loaded on bigels, free bigels, or free Quer for 45 days as daily gavage. Semen was analyzed, followed by the assessment of DNA integrity. Count, motility, and normal morphology reached the healthy control group at the bigel-Quer-treated one. Moreover, all of these parameters were significantly higher in the bigel-Quer group than the Quer and bigel, alone. The percent of sperms with head and tail abnormality decreased considerably in the bigel-Quer group compared with the Quer, free bigel, and NAFLD groups. Serum testosterone levels significantly increased and reached the healthy control group in the bigel-Quer group. DNA fragmentation of sperm significantly decreased in the bigel-Quer group (p < 0.05). The bigel showed synergistic effects with Quer for treating infertility in rats with NAFLD.

Protective and Therapeutic Effect of Quercetin in Hepatotoxicity Induced by Sepsis in Rats

Protective and Therapeutic Effect of Quercetin in Hepatotoxicity Induced by Sepsis in Rats

Senolytic agent Quercetin ameliorates intervertebral disc degeneration via the Nrf2/NF-κB axis

Intervertebral disc degeneration (IDD) represents major cause of low back pain. Quercetin (QUE) is one of the approved senolytic agents. In this study, we evaluated the protective effects of QUE on IDD development and its underlying mechanism. Effects of senolytic agent QUE on the viability of nucleus pulposus cells (NPCs) were measured by CCK-8 assays and EdU staining. The senescence associated secreted phenotype (SASP) factors expressions were measured by qPCR, western blot, and ELISA; and NF-κB pathway was detected by immunofluorescence and western blot. Molecular docking was applied to predict the interacting protein of QUE; while Nrf2 was knocked down by siRNAs to confirm its role in QUE regulated senescence phenotype. X-ray, MRI, Hematoxylin-Eosin and Safranin O-Fast green staining were performed to evaluate the therapeutic effects of QUE on IDD in the puncture-induced rat model. In in vitro experiments, QUE inhibited SASP factors expression and senescence phenotype in IL-1β-treated NPCs. Mechanistically, QUE suppressed IL-1β induced activation of the NF-κB pathway cascades; it was also demonstrated in molecular docking and knock down studies that QUE might bind to Keap1-Nrf2 complex to suppress NF-κB pathway. In vivo, QUE ameliorated the IDD process in the puncture-induced rat model. Together the present work suggests that QUE inhibits SASP factors expression and senescence phenotype in NPCs and ameliorates the progression of IDD via the Nrf2/NF-κB axis, which supports senolytic agent QUE as a potential therapeutic agent for the treatment of IDD.

The Therapeutic Effects of Quercetin in a Canine Model of Low-dose Lipopolysaccharide-Induced Sepsis Compared with Hydrocortisone

BACKGROUND: Canine low-dose sepsis model provides a reliable setting to study innovative drugs. Li- popolysaccharides (LPS), a major constituent of bacterial outer membrane, have been demonstrated to play a critical role in the initiation of pathogenesis. Lipopolysaccharide-induced sepsis has been extensively studied in laboratory animals; but its importance has mainly remained unknown in dogs. OBJECTIVES: The aim of the present survey was to examine the effectiveness of quercetin, along with hydrocortisone on clinical and hematological alterations, and organ failure (liver and heart) in low-dose lipo- polysaccharide-induced canine sepsis model. METHODS: For this purpose, fifteen clinically healthy mixed dogs were randomly divided into three equal groups. Lipopolysaccharide (0.1 μg/kg, IV) was injected to dogs in group A (control). Group B was similar to group A, but quercetin bolus (2 mg/kg, IV, once) was injected 40 minutes after LPS injection. Group C was similar to group B; however, hydrocortisone bolus (2 mg/kg, IV, once) was administered instead of quercetin. Serum levels of glucose, total protein, albumin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase isoenzyme muscle/brain (CK-MB), lactate dehydrogenase (LDH) and cardiac troponin I (cTn-I) concentration were measured by commercial kits. RESULTS: In control group, red blood cells (RBCs), hemoglobin (Hb), and hematocrit (HCT) significant- ly decreased and serum activities of AST, ALP, LDH, CK-MB, and plasma cTn-I significantly increased (P<0.05). RBCs, Hb, and HCT significantly increased in quercetin group, compared with hydrocortisone and control groups (P<0.05). Quercetin group significantly decreased LDH, CK-MB, and cTn-I compared with hydrocortisone and control groups (P<0.05). Quercetin significantly decreased AST in comparison to control group and ALP in comparison to hydrocortisone group, also (P<0.05). CONCLUSIONS: These results suggest that quercetin protects RBCs in the early stages of sepsis and de- creases organs dysfunction (heart and liver), therefore it has a positive influence on sepsis and may be more effective than routine corticosteroid (hydrocortisone) therapy.

The phytoestrogen, quercetin, in serum, uterus and ovary as a potential treatment for dehydroepiandrosterone-induced polycystic ovary syndrome in the rat.

The exact mechanisms of polycystic ovary syndrome (PCOS) are unknown and there is no effective cure for the disease. The aim of this study was to evaluate the alterations in serum oestradiol and adiponectin levels and in the expression of some important genes in the uterine and ovarian tissues of PCOS rats. The therapeutic effect of quercetin on PCOS was also assessed. Rats were divided into five groups: control, ethanol, quercetin (Q), PCOS and PCOS+Q. After 30 days of oral treatments, the rats' ovaries and uteri were removed and nesfatin-1, aromatase and adipoR1 expressions were quantified with real-time polymerase chain reaction. Serum adiponectin and oestradiol levels were evaluated using enzyme-linked immunosorbent assay technique. The results of this study showed that expression of nesfatin-1 and adipoR1 genes and adiponectin serum levels decreased in the PCOS rats, but aromatase expression and oestradiol level increased. Treatment with quercetin increased the adiponectin level and expression of adipoR1 and nesfatin-1 and decreased both the expression of aromatase and the oestradiol level. Quercetin improved PCOS by phytoestrogenic effects and mimicking oestrogen's function. Quercetin also affects important factors in both the uterus and ovary and could improve the obesity and the diabetic and infertility symptoms of PCOS.

The possible protective effect of quercetin on methotrexate induced hepatotoxicity in albino rats: biochemical , histological and immunohistochemical study

Background:Methotrexate(Mtx) is an antineoplastic and immunosuppressive drug. That may cause hepatotoxicity, whereas quarcetin has anti-inflammatory and antiproliferative properties.Aim of the work: This study aimed to investigate the possible protective and therapeutic effects of quercetin against methotrexate (Mtx)-induced hepatotoxicity with biochemical and histopathological studies in ratsMaterials and methods: twenty six Wister albino rats were equally divided into four experimental groups: Control (group I), Mtx group (group II) rats received (single dose of Mtx 20 mg/kg i.p.). QCT protective group (group III) rats pre-treated with QCT (20 mg/kg orally daily for 7 days then Mtx administration. QCT therapeutic group (group IV) rats cotreated with Mtx(20 mg/kg for i.p, single dose)then QCT were given as before .Following treatment, the animals were sacrificed, and liver tissue samples were histopathologically evaluated using H&E, Masson's, PCNA staining, and serum transaminases were measured and statistically compared across all groupsResults:Group II (Mtx group) demonstrated hydrobic degeneration of hepatocytes, congestion of hepatic sinusoids ,central veins and portal veins .An apparent increase in collagenous fibers distribution around the central vein and portal tract was detected .In groups III (protected QCT), and group IV (QCT therapeutic groups), showed less histological injury compared to Mtx group as regards liver sections ,but pretreatment with QCT in group III was more effective than in group IV except for mild dilation of sinusoids Conclusion: Methotrexate has a deleterious effect on the liver. Quaricetin may be a potential adjuvant drug to reduce the hepatic side effects observed during Mtx therapy for various clinical conditions.

Potent Inhibitory Effects of Quercetin on Inflammatory Responses of Collagen-Induced Arthritis in Mice.

Production of tumor necrosis factor (TNF)-α by inflammatory cells in lesions is the hallmark of the pathogenesis of rheumatoid arthritis (RA). Regulation of inflammatory responses in knee joints of patients with RA is critical for improving severe symptoms. Flavonoids have inhibitory effects on the acute and chronic inflammatory responses caused by TNF-α. The flavonoid quercetin (QUER) is one of the most prominent dietary antioxidants. The present study investigated the preventive and therapeutic effects of QUER on inflammatory responses in collagen-induced arthritis (CIA) in mice. Mice with CIA, a mouse model for RA, were treated with QUER orally three times a week either from the second immunization with collagen (day 21) or day 28 when symptoms of CIA had developed midway. In both cases, inflammation-related clinical scores of knee joints were significantly reduced by treatment with QUER. Histological analyses showed that the representative characteristics of RA, such as damage to interchondral joints, infiltration of inflammatory cells, and pannus formation, were significantly reduced by QUER treatment. Oral administration of QUER significantly decreases lipopolysaccharide (LPS)-induced TNF-α production in a dose-dependent manner. Expression of TNF- α mRNA in knee joints was decreased in QUER-treated mice, compared with those of CIA controls. These results suggest that oral administration of QUER might effectively improve symptoms of RA.

Quercetin inhibits proliferation of endometriosis regulating cyclin D1 and its target microRNAs in vitro and in vivo

Quercetin (3,3′,4′,5,7-pentahydroxyflavone) is a major dietary flavonol found in diverse fruits and vegetables such as onions, cauliflower, apple skin, lettuce and chili peppers. In recent studies, quercetin is reported as a functional compound and shows a wide range of biological effects such as antioxidant, anti-inflammatory and antiangiogenic properties in obesity, diabetes, cardiovascular diseases and various cancers. However, to date, the therapeutic effect of quercetin on the progression of endometriosis, which is a common gynecological disease in reproductive-aged women and brings chronic pelvic pain and infertility, has not been examined in depth. Results of this study demonstrated that quercetin inhibited the proliferation and induced the cell cycle arrest in VK2/E6E7 and End1/E6E7 cells. Furthermore, it induced cell apoptosis with DNA fragmentation, loss of mitochondrial membrane potential and reactive oxygen species production. The effects accompanied down-regulation of ERK1/2, P38 MAPK and AKT signaling molecules. Additionally, the administration of quercetin indicated antiproliferative and anti-inflammatory effects on endometriosis autoimplanted mouse models. The mRNA expression of Ccnd1 significantly decreased in response to quercetin intraperitoneal injection when compared to that in vehicle-treated mice. The knockdown of CCND1 mRNA attenuated the proliferation with sub-G0/G1 cell cycle arrest and increased the apoptosis of VK2/E6E7 and End1/E6E7 cells. Furthermore, the treatment of quercetin induced miR-503-5p, miR-1283, miR-3714 and miR-6867-5p related to CCND1 in both cell lines and also stimulated miR-503-5p and miR-546 expression in the mouse model. Hence, quercetin may potentially act as a natural therapeutic to reduce and treat human endometriosis.

The effects of Quercetin on miRNA-21 expression in MCF-7 cells

Background: Cancer prevention, by the use of natural dietary or secondary metabolites in plants is one of the strategies has been attracting some of the scientific interests. One of these natural agents is Quercetin, which has anti-metastatic and anti-cancer effects. MiR-21 among different miRNAs is one of the most important frequently up-regulated miRs in numerous cancers including breast and increase cell proliferation and decrease apoptosis and therefore leads to increases in cancer incidence. We assessed the effects of Quercetin on cell viability, MiR-21, Maspin and PTEN gene expression in the MCF-7 cell line.Materials & Methods: The human MCF-7 breast cancer cell line was cultured in RPMI1640 and treated with different concentrations of Quercetin (0.01-100 μM) for 24 hours. The cytotoxic effect of Quercetin on MCF-7 viability was determined using Methyl-Thiazolyl-Tetrazolium (MTT) assay by IC50 determination. The relative expression of MiR-21, Maspin, and PTEN gene expression were determined by real-time Polymerase Chain Reaction (PCR).Results: The maximum inhibitory effect of Quercetin on cell viability was observed at 100 μM after 24-hour incubation. The expression of MiR-21 in the treated cells compared to controls was significantly decreased after treatment with three different concentrations of Quercetin. In addition, expression of Maspin and PTEN in the treated cells compared to controls was significantly increased.Conclusions: Quercetin decreases cell viability and miR-21 gene expression in a dose-dependent manner. Also, Quercetin decreases mir-21 gene expression and increases Maspin and PTEN expression in MCF-7 breast cancer cell line. The growth inhibitory properties and therapeutic effect of Quercetin on the breast cancer may be mediated by reduction of miR-21 expression, and for verifying this hypothesis and the possible therapeutic implication of Quercetin in this direction further studies are necessary.