Quercetin Limits Tumor Immune Escape through PDK1/CD47 Axis in Melanoma.

Quercetin (3,3[Formula: see text],4[Formula: see text],5,7-pentahydroxyflavone) is a bioactive plant-derived flavonoid, abundant in fruits and vegetables, that can effectively inhibit the growth of many types of tumors without toxicity. Nevertheless, the effect of quercetin on melanoma immunology has yet to be determined. This study aimed to investigate the role and mechanism of the antitumor immunity action of quercetin in melanoma through both in vivo and in vitro methods. Our research revealed that quercetin has the ability to boost antitumor immunity by modulating the tumor immune microenvironment through increasing the percentages of M1 macrophages, CD8[Formula: see text] T lymphocytes, and CD4[Formula: see text] T lymphocytes and promoting the secretion of IL-2 and IFN-[Formula: see text] from CD8[Formula: see text] T cells, consequently suppressing the growth of melanoma. Furthermore, we revealed that quercetin can inhibit cell proliferation and migration of B16 cells in a dose-dependent manner. In addition, down-regulating PDK1 can inhibit the mRNA and protein expression levels of CD47. In the rescue experiment, we overexpressed PDK1 and found that the protein and mRNA expression levels of CD47 increased correspondingly, while the addition of quercetin reversed this effect. Moreover, quercetin could stimulate the proliferation and enhance the function of CD8[Formula: see text] T cells. Therefore, our results identified a novel mechanism through which CD47 is regulated by quercetin to promote phagocytosis, and elucidated the regulation of quercetin on macrophages and CD8[Formula: see text] T cells in the tumor immune microenvironment. The use of quercetin as a therapeutic drug holds potential benefits for immunotherapy, enhancing the efficacy of existing treatments for melanoma.

Protective Effects of Aspirin Supplemented With Quercetin in L-NAME-Induced Preeclampsia-Like Rats.

Aspirin supplemented with quercetin was reported to enhance the therapeutic effects of aspirin in a rat model of preeclampsia. In this study, the underlying mechanisms were further explored. Preeclampsia was induced by L-NAME (50 mg/kg/day) via oral gavage from gestation day (GD)14 to GD19. Aspirin (1.5 mg/kg/day) administration was performed using aspirin mixed with rodent dough from GD0 to GD19. The administration of quercetin (2 mg/kg/day) was performed by intraperitoneal infusion from GD0 to GD19. Protein levels were evaluated using ELISA or Western blot, and microRNA (miRNA) level was evaluated by RT-PCR. Aspirin supplemented with quercetin ameliorated the increase of systolic blood pressure (SBP), proteinuria, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) levels, and improved the pregnancy outcomes in preeclampsia rats. Aspirin supplemented with quercetin inhibited miR-155 expression in preeclampsia rats. The decreased miR-155 level in placenta further increased the protein level of SOCS1 and inhibited the phosphorylation of p65. In this study, we demonstrated that aspirin supplemented with quercetin enhanced the effects of aspirin for the treatment of preeclampsia.

Hawthorn leaf flavonoids alleviate the deterioration of atherosclerosis by inhibiting SCAP-SREBP2-LDLR pathway through sPLA2-â ¡A signaling in macrophages in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Hawthorn leaves are a combination of the dried leaves of the Rosaceae plants, i.e., Crataegus pinnatifida Bge. or Crataegus pinnatifida Bge. var. major N. E. Br., is primarily cultivated in East Asia, North America, and Europe. hawthorn leaf flavonoids (HLF) are the main part of extraction. The HLF have demonstrated potential in preventing hypertension, inflammation, hyperlipidemia, and atherosclerosis. However, the potential pharmacological mechanism behind its anti-atherosclerotic effect has yet to be explored. AIM OF THE STUDY: The in vivo and in vitro effects of HLF on lipid-mediated foam cell formation were investigated, with a specific focus on the levels of secreted phospholipase A2 type IIA (sPLA2-II A) in macrophage cells. MATERIALS AND METHODS: The primary constituents of HLF were analyzed using ultra-high performance liquid chromatography and liquid chromatography-tandem mass spectrometry. In vivo, HLF, at concentrations of 5 mg/kg, 20 mg/kg, and 40 mg/kg, were administered to apolipoprotein E knockout mice (ApoE-/-) fed by high-fat diet (HFD) for 16 weeks. Aorta and serum samples were collected to identify lesion areas and lipids through mass spectrometry analysis to dissect the pathological process. RAW264.7 cells were incubated with oxidized low-density lipoprotein (ox-LDL) alone, or ox-LDL combined with different doses of HLF (100, 50, and 25 µg/ml), or ox-LDL plus 24-h sPLA2-IIA inhibitors, for cell biology analysis. Lipids and inflammatory cytokines were detected using biochemical analyzers and ELISA, while plaque size and collagen content of plaque were assessed by HE and the Masson staining of the aorta. The lipid deposition in macrophages was observed by Oil Red O staining. The expression of sPLA2-IIA and SCAP-SREBP2-LDLR was determined by RT-qPCR and Western blot analysis. RESULTS: The chemical profile of HLF was studied using UPLC-Q-TOF-MS/MS, allowing the tentative identification of 20 compounds, comprising 1 phenolic acid, 9 flavonols and 10 flavones, including isovitexin, vitexin-4″-O-glucoside, quercetin-3-O-robibioside, rutin, vitexin-2″-O-rhamnoside, quercetin, etc. HLF decreased total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and non-high-density lipoprotein cholesterol (non-HDL-C) levels in ApoE-/- mice (P < 0.05), reduced ox-LDL uptake, inhibited level of inflammatory factors, such as IL-6, IL-8, TNF-α, and IL-1ꞵ (P < 0.001), and alleviated aortic plaques with a thicker fibrous cap. HLF effectively attenuated foam cell formation in ox-LDL-treated RAW264.7 macrophages, and reduced levels of intracellular TC, free cholesterol (FC), cholesteryl ester (CE), IL-6, TNF-α, and IL-1ß (P < 0.001). In both in vivo and in vitro experiments, HLF significantly downregulated the expression of sPLA2-IIA, SCAP, SREBP2, LDLR, HMGCR, and LOX-1 (P < 0.05). Furthermore, sPLA2-IIA inhibitor effectively mitigated inflammatory release in RAW264.7 macrophages and regulated SCAP-SREBP2-LDLR signaling pathway by inhibiting sPLA2-IIA secretion (P < 0.05). CONCLUSION: HLF exerted a protective effect against atherosclerosis through inhibiting sPLA2-IIA to diminish SCAP-SREBP2-LDLR signaling pathway, to reduce LDL uptake caused foam cell formation, and to slow down the progression of atherosclerosis in mice.

Quercetin counteracts monosodium glutamate to mitigate immunosuppression in the thymus and spleen via redox-guided cellular signaling.

BACKGROUND: Chronic inflammation brought on by oxidative stress can result in several immunopathologies. Natural compounds with antioxidant characteristics, like quercetin, have shown effectiveness in reducing oxidative damage and regulating the immune response. PURPOSE: The commonly used food additive monosodium glutamate (M) causes immunosuppression by disrupting redox equilibrium and inducing oxidative stress. The goal of this work is to examine the therapeutic potential of quercetin against immunotoxicity brought on by M, revealing the molecular route implicated in such immunopathology by targeting the thymus and spleen, to support the development of future anti-inflammatory and antioxidant therapies. STUDY DESIGN AND METHODS: M-fed rats were employed as an immunotoxicity model and were supplemented with quercetin for four weeks. Hematological and biochemical parameters were measured; H&E staining, immunohistochemistry, flow cytometry, real-time quantitative PCR, and western blotting were performed. RESULTS: Based on the findings, TLR4 was activated by M to cause oxidative stress-mediated inflammation, which was alleviated by the supplementation of quercetin by modulating redox homeostasis to neutralize free radicals and suppress the inflammatory response. To prevent M-induced inflammation, quercetin demonstrated anti-inflammatory functions by blocking NF-kB activation, lowering the production of pro-inflammatory cytokines, and increasing the release of anti-inflammatory cytokines. By normalizing lipid profiles and lowering the potential risk of immunological deficiency caused by M, quercetin also improves lipid metabolism. Additionally, it has shown potential for modifying insulin levels, suggesting a possible function in controlling M-induced alteration in glucose metabolism. The addition of quercetin to M enhanced the immune response by improving immunoglobulin levels and CD4/CD8 expression in the thymus and spleen. Additionally, quercetin inhibited apoptosis by controlling mitochondrial caspase-mediated cellular signaling, suggesting that it may be able to halt cell death in M-fed rats. CONCLUSION: The results of this study first indicate that quercetin, via modulating redox-guided cellular signaling, has a promising role in reducing immune disturbances. This study illuminates the potential of quercetin as a safe, natural remedy for immunopathology caused by M, including thymic hypoplasia and/or splenomegaly, and paves the way for future anti-inflammatory and antioxidant supplements.

The Effect and Mechanism of Fructus lycii on Improvement of Exercise Fatigue Using a Network Pharmacological Approach with in vitro Experimental Verification.

Objective: This study aimed to investigate the effect and underlying mechanism of Fructus lycii in improving exercise fatigue. Methods: A network pharmacological approach was used to explore potential mechanisms of action of Fructus lycii. Skeletal muscle C2C12 cells and immunofluorescence were employed to verify the effect and mechanism of the representative components in Fructus lycii predicted by network pharmacological analysis. Results: Six potential active components, namely quercetin, ß-sitosterol, stigmasterol, 7-O-methylluteolin-6-C-beta-glucoside_qt, atropine, and glycitein, were identified to have potency in improving exercise fatigue via multiple pathways, such as the PI3K-Akt, neuroactive ligand-receptor interaction, IL-17, TNF, and MAPK signaling pathways. The immunofluorescence results indicated that quercetin, a significant active component in Fructus lycii, increased the mean staining area of 2-NBDG, TMRM, and MitoTracker, and decreased the area of CellRox compared to the control. Furthermore, the protein expression levels of p-38 MAPK, p-MAPK, p-JNK, p-PI3K, and p-AKT markedly increased after quercetin treatment. Conclusion: Fructus lycii might alleviate exercise fatigue through multiple components and pathways. Among these, quercetin appears to improve exercise fatigue by enhancing energy metabolism and reducing oxidative stress. The PI3K-AKT and MAPK signaling pathways also appear to play a role in this process.

Enhanced Chemoprevention of Prostate Cancer by Combining Arctigenin with Green Tea and Quercetin in Prostate-Specific Phosphatase and Tensin Homolog Knockout Mice.

The low bioavailability of most phytochemicals limits their anticancer effects in humans. The present study was designed to test whether combining arctigenin (Arc), a lignan mainly from the seed of Arctium lappa, with green tea (GT) and quercetin (Q) enhances the chemopreventive effect on prostate cancer. We performed in vitro proliferation studies on different cell lines. We observed a strong synergistic anti-proliferative effect of GT+Q+Arc in exposing androgen-sensitive human prostate cancer LNCaP cells. The pre-malignant WPE1-NA22 cell line was more sensitive to this combination. No cytotoxicity was observed in normal prostate epithelial PrEC cells. For an in vivo study, 3-week-old, prostate-specific PTEN (phosphatase and tensin homolog) knockout mice were treated with GT+Q, Arc, GT+Q+Arc, or the control daily until 16 weeks of age. In vivo imaging using prostate-specific membrane antigen (PSMA) probes demonstrated that the prostate tumorigenesis was significantly inhibited by 40% (GT+Q), 60% (Arc at 30 mg/kg bw), and 90% (GT+Q+Arc) compared to the control. A pathological examination showed that all control mice developed invasive prostate adenocarcinoma. In contrast, the primary lesion in the GT+Q and Arc alone groups was high-grade prostatic intraepithelial neoplasia (PIN), with low-grade PIN in the GT+Q+Arc group. The combined effect of GT+Q+Arc was associated with an increased inhibition of the androgen receptor, the PI3K/Akt pathway, Ki67 expression, and angiogenesis. This study demonstrates that combining Arc with GT and Q was highly effective in prostate cancer chemoprevention. These results warrant clinical trials to confirm the efficacy of this combination in humans.

Maternal quercetin supplementation improved lipopolysaccharide-induced cognitive deficits and inflammatory response in a rat model of maternal immune activation.

BACKGROUND: There is strong evidence that prenatal infection during a specific period of brain development increases the risk of neurodevelopmental disorders, partly through immune-inflammatory pathways. This suggests that anti-inflammatory agents could prevent these disorders by targeting the maternal inflammatory response. In the present study, we used a rat model of maternal immune activation (MIA) to examine whether maternal quercetin (QE) supplementation can alleviate behavioral deficits and inflammatory mediators in the prefrontal cortex (PFC) and hippocampus of adult male offspring. METHODS: Pregnant rats were supplemented with QE (50 mg/kg) or vehicle throughout pregnancy and injected with either lipopolysaccharide (0.5 mg/kg) or saline on gestational days 15/16. At postnatal day 60, we evaluated the offspring's behavior, hippocampal and prefrontal cortex glial density, pro-inflammatory gene expression, and neuronal survival. RESULTS: Our data showed that maternal QE supplementation can prevent working and recognition memory impairments in adult MIA offspring. This behavioral improvement correlates with the decrease in MIA-induced expression of pro-inflammatory genes, microglia, and astrocyte densities, without affecting neuronal survival, in both PFC and CA1 hippocampus areas. CONCLUSION: Therefore, our study supports the potential preventive effect of QE on MIA-induced behavioral dysfunctions, at least in part, by suppressing the glial-mediated inflammatory response.

Quercetin ameliorates ulcerative colitis by activating aryl hydrocarbon receptor to improve intestinal barrier integrity.

Ulcerative colitis (UC) pathogenesis is largely associated with intestinal epithelial barrier dysfunction. A therapeutic approach to UC involves the repair of damaged intestinal barrier. Our study aimed to investigate whether aryl hydrocarbon receptor (AhR) mediated the intestinal barrier repair effects of quercetin to ameliorate UC. 3% dextran sulfate sodium was used to induce colitic mice, and quercetin (25, 50, and 100 mg/kg) was administered orally for 10 days to assess the therapeutic effects. In vitro, Caco-2 cells were used to explore the effect of quercetin on tight junction protein expression and AhR activation. The results showed that quercetin alleviated colitic mice by restoring tight junctions (TJs) integrity via an AhR-dependent manner (p < 0.05). In vitro, quercetin dose-dependently elevated the expressions of TJs protein ZO-1 and Claudin1, and activated AhR by enhancing the expression of CYP1A1 and facilitating AhR nuclear translocation in Caco-2 cells (p < 0.05). While AhR antagonist CH223191 reversed the therapeutic effects of quercetin (p < 0.05) and blocked quercetin-induced AhR activation and enhancement of TJs protein (p < 0.05). In conclusion, quercetin repaired intestinal barrier dysfunction by activating AhR-mediated enhancement of TJs to alleviate UC. Our research offered new perspectives on how quercetin enhanced intestinal barrier function.

Quercetin improved hepatic circadian rhythm dysfunction in middle-aged mice fed with vitamin D-deficient diet.

We aimed to determine whether quercetin is capable of improving circadian rhythm and metabolism disorder under vitamin D-deficient condition. Middle-aged mice were randomly divided into four groups, namely, control (CON), vitamin D-deficient diet (VDD), quercetin (Q), and quercetin intervention in vitamin D-deficient diet (VDQ), with a total of 12 weeks' intervention. Mice were sacrificed at zeitgeber time1 (ZT1) and ZT13 time points. At ZT1, circadian locomotor output cycle kaput (CLOCK) protein expression from VDD, Q, and VDQ groups; CRY1 from Q group; and CRY2 from VDD group were significantly lower compared to CON group. The mRNA expression of Sirt1, Bmal1, Clock, Cry1, and Cry2 in VDQ groups, also Bmal1, Clock, and Cry1 from Q group, were significantly decreased compared to CON group. At ZT13, compared to CON group, fasting insulin and homeostasis model assessment-insulin resistance (HOMA-IR) were higher in VDD group; BMAL1 was significantly increased, while CLOCK and CRY1 protein were significantly decreased from VDD group; CLOCK protein from VDQ group was significantly higher compared to CON, VDD, and Q groups, and also, BMAL1 protein expression from VDQ group was elevated compared to CON group. The mRNA expression of Bmal1, Clock, Per2, Cry1, and Cry2 in VDQ groups were significantly increased compared to CON groups. The mRNA expression of Bmal1 from VDQ group was decreased compared to both VDD and Q group. In conclusion, vitamin D-deficient diet resulted in a disordered liver circadian rhythm, and quercetin improved the hepatic circadian desynchronization. Quercetin supplementation might be effective for balancing circadian rhythm under vitamin D-deficient condition.

Kaempferol-3-O-(2″-O-galloyl-ß-D-glucopyranoside): a novel neuroprotective agent from Diospryros kaki against cerebral ischemia-induced brain injury.

Our previous study demonstrated neuroprotective and therapeutic effects of a standardized flavonoid extract from leaves of Diospyros kaki L.f. (DK) on middle cerebral artery occlusion-and-reperfusion (MCAO/R)-induced brain injury and its underlying mechanisms. This study aimed to clarify flavonoid components responsible for the effects of DK using in vitro and in vivo transient brain ischemic models. Organotypic hippocampal slice cultures (OHSCs) subjected to oxygen- and glucose-deprivation (OGD) were performed to evaluate in vitro neuroprotective activity of DK extract and nine isolated flavonoid components. MCAO/R mice were employed to elucidate in vivo neuroprotective effects of the flavonoid component that exhibited the most potent neuroprotective effect in OHSCs. DK extract and seven flavonoids [quercetin, isoquercetin, hyperoside, quercetin-3-O-(2″-O-galloyl-ß-D-galactopyranoside), kaempferol, astragalin, and kaempferol-3-O-(2″-O-galloyl-ß-D-glucopyranoside) compound (9)] attenuated OGD-induced neuronal cell damage and compound (9) possessed the most potent neuroprotective activity in OHSCs. The MCAO/R mice showed cerebral infarction, massive weight loss, characteristic neurological symptoms, and deterioration of neuronal cells in the brain. Compound (9) and a reference drugs, edaravone, significantly attenuated these physical and neurological impairments. Compound (9) mitigated the blood-brain barrier dysfunction and the change of glutathione and malondialdehyde content in the MCAO mouse brain. Edaravone suppressed the oxidative stress but did not significantly affect the blood-brain barrier permeability. The present results indicated that compound (9) is a flavonoid constituent of DK with a potent neuroprotective activity against transient ischemia-induced brain damage and this action, at least in part, via preservation of blood-brain barrier integrity and suppression of oxidative stress caused by ischemic insult.

Active ingredient and mechanistic analysis of traditional Chinese medicine formulas for the prevention and treatment of COVID-19: Insights from bioinformatics and in vitro experiments.

Coronavirus disease 2019 (COVID-19) is an acute infectious disease caused by a novel coronavirus. Traditional Chinese medicine (TCM) has been proven to have a potential curative effect on COVID-19. This study preliminarily analyzed the existing TCM prescription's key components and action mechanisms for preventing and treating COVID-19 using bioinformatic and experimental methods. Association and clustering analysis reveals that the "HQ + FF + BZ" drug combination had a strong correlation and confidence in 93 TCM prescriptions and may affect the progression of COVID-19 through inflammatory pathways such as the TNF signaling pathway. Further molecular docking revealed that quercetin has a higher affinity for IL6 and IL10 in the TNF signaling pathway associated with COVID-19. In vitro experiments demonstrated that quercetin could effectively reduce the levels of the inflammatory factor IL-6 and increase the anti-inflammatory factor IL-10, alleviating inflammation impact on cells. Our results provide a new understanding of the molecular mechanism of TCM prevention and treatment of COVID-19, which is helpful to the development of new diagnosis and treatment schemes for COVID-19.

Investigating the therapeutic mechanism of Xiaotan Sanjie Formula for gastric cancer via network pharmacology and molecular docking: A review.

Xiaotan Sanjie Formula (XTSJF), a traditional Chinese prescription, holds promising potential in addressing gastric cancer (GC). Despite this, the fundamental constituents and underlying mechanisms that define XTSJF's attributes remain enigmatic. Against this backdrop, this study endeavors to unravel the latent mechanisms driving XTSJF's impact on GC, leveraging the synergistic prowess of network pharmacology and molecular docking methodologies. To understand the potential mechanism of XTSJF against GC, this study used network pharmacology, molecular docking, and bioinformatics analytic methodologies. There are 135 active components where the active ingredients with a higher degree value are quercetin, ß-sitosterol, naringenin, nobiletin, and kaempferol and 167 intersecting targets in which TP53, MAPK3, MAPK1, STAT3, and AKT1 were key targets were identified in XTSJF in the treatment of GC. According to GO and KEGG analyses, XTSJF is mostly involved in the positive control of transcription from the RNA polymerase II promoter, enzyme interaction, and other biological processes in GC. KEGG analysis shows that XTSJF treated GC primarily by regulating signaling pathways including the TNF, PI3K-Akt, and MAPK signaling pathways. According to the results of the PPI network and molecular docking, quercetin, ß-sitosterol, naringenin, nobiletin, and kaempferol exhibit stronger affinity with TP53, MAPK3, MAPK1, STAT3, and AKT1. This study indicates the active components of XTSJF as well as its possible molecular mechanism against GC, and it serves as a foundation for future fundamental research.

Mechanisms of action underlying Shentong Zhuyu decoction based treatment of rheumatoid arthritis using systems biology and computer-aided drug design.

Rheumatoid arthritis is an autoimmune disease characterized by chronic polyarticular pain, for which no cure currently exists. In Chinese medicine, rheumatoid arthritis (RA) is believed to be caused by phlegm and blood stagnation. Shentong Zhuyu decoction can be used to treat RA, as it promotes blood circulation, resolves blood stasis, and relieves pain. In our study, we used network pharmacology and computer-aided drug design to evaluate the components, active compounds, and targets of Shentong Zhuyu decoction (STZY). Our results suggest that STZY contains active compounds such as quercetin, luteolin, and formononetin that regulate immune network targets. RA associated genes are enriched in pathways including those associated with nuclear factor kappa B, phosphatidylinositol-3-kinase/AKT, and hypoxia inducible factor 1 signaling. The main active compounds in STZY (quercetin and luteolin) were derived from Achyranthis Bidentatae Radix, Carthami Flos, licorice, Cyperi Rhizoma, and Myrrha and targeted the pro-inflammatory cytokines interleukin 2, interleukin 1 alpha, interleukin 1 beta, and interleukin 6. In addition, the compounds quercetin, luteolin, and formononetin in these herbs can target the anti-inflammatory cytokines interleukin 4 and interleukin 10. Our results suggest that STZY can balance the immune network, promote an anti-inflammatory environment, and reduce the clinical symptoms of RA. Based on the close relationship between inflammatory response and osteoclast formation, we hypothesized that STZY may inhibit inflammation and alleviate bone destruction in RA. Our findings indicate that STZY can treat RA through multiple components, targets, and pathways. This study may provide a reference for the clinical application of STZY in RA treatment.

Regulatory Effects of Quercetin on Bone Homeostasis: Research Updates and Future Perspectives.

The imbalance of bone homeostasis has become a major public medical problem amid the background of an aging population, which is closely related to the occurrence of osteoporosis, osteoarthritis, and fractures. Presently, most drugs used in the clinical treatment of bone homeostasis imbalance are bisphosphonates, calcitonin, estrogen receptor modulators, and biological agents that inhibit bone resorption or parathyroid hormone analogs that promote bone formation. However, there are many adverse reactions. Therefore, it is necessary to explore potential drugs. Quercetin, as a flavonol compound with various biological activities, is widely distributed in plants. Studies have found that quercetin can regulate bone homeostasis through multiple pathways and targets. An in-depth exploration of the pharmacological mechanism of quercetin is of great significance for the development of new drugs. This review discusses the therapeutic mechanisms of quercetin on bone homeostasis, such as regulating the expression of long non-coding RNA, signaling pathways of bone metabolism, various types of programmed cell death, bone nutrients supply pathways, anti-oxidative stress, anti-inflammation, and activation of Sirtuins. We also summarize recent progress in improving quercetin bioavailability and propose some issues worth paying attention to, which may help guide future research efforts.

Quercetin Attenuates Atherosclerosis via Modulating Apelin Signaling Pathway Based on Plasma Metabolomics.

OBJECTIVE: To interpret the pharmacology of quercetin in treatment of atherosclerosis (AS). METHODS: Fourteen apolipoprotein E-deficient (ApoE-/-) mice were divided into 2 groups by a random number table: an AS model (ApoE-/-) group and a quercetin treatment group (7 in each). Seven age-matched C57 mice were used as controls (n=7). Quercetin [20 mg/(kg·d)] was administered to the quercetin group intragastrically for 8 weeks for pharmacodynamic evaluation. Besides morphological observation, the distribution of CD11b, F4/80, sirtuin 1 (Sirt1) and P21 was assayed by immunohistochemistry and immunofluorescence to evaluate macrophage infiltration and tissue senescence. Ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MSC/MS) was performed to study the pharmacology of quercetin against AS. Then, simultaneous administration of an apelin receptor antagonist (ML221) with quercetin was conducted to verify the possible targets of quercetin. Key proteins in apelin signaling pathway, such as angiotensin domain type 1 receptor-associated proteins (APJ), AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), tissue plasminogen activator (TPA), uncoupling protein 1 (UCP1) and angiotensin II receptor 1 (AT1R), were assayed by Western blot. RESULTS: Quercetin administration decreased lipid deposition in arterial lumen and improved the morphology of ApoE-/- aortas in vivo. Quercetin decreased the densities of CD11b, F4/80 and P21 in the aorta and increased the level of serum apelin and the densities of APJ and Sirt1 in the aorta in ApoE-/- mice (all P<0.05). Plasma metabolite profiling identified 118 differential metabolites and showed that quercetin affected mainly glycerophospholipids and fatty acyls. Bioinformatics analysis suggested that the apelin signaling pathway was one of the main pathways. Quercetin treatment increased the protein expressions of APJ, AMPK, PGC-1α, TPA and UCP1, while decreased the AT1R level (all P<0.05). After the apelin pathway was blocked by ML221, the effect of quercetin was abated significantly, confirming that quercetin attenuated AS by modulating the apelin signaling pathway (all P<0.05). CONCLUSION: Quercetin alleviated AS lesions by up-regulation the apelin signaling pathway.

Efficacy of hydroethanolic extract of Randia aculeata seed against the southern cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) on naturally infested cattle under field conditions.

The cattle tick Rhipicephalus (Boophilus) microplus is a major problem of concern for cattle industry in tropical and subtropical areas. Control of cattle tick is based mainly on the use of chemical acaricides, which has contributed to the emerging problem of selection of resistant tick lineages. Plants have been used as an alternative to conventional acaricidal drugs. On the other hand, the acaricidal activity of hydroethanolic extract of Randia aculeata seed (EHRA) has been demonstrated against R. microplus under laboratory conditions. However, the utility of EHRA seed as a potential acaricidal needs to be determined under field conditions. For this reason, the aim of this study was to evaluate the efficacy of the EHRA against R. microplus sprayed on naturally infested calves, determine the effect of the EHRA seed on acetylcholinesterase activity in R. microplus larval and identify the chemical composition of EHRA. Forty-five male calves were divided in three groups and treated with: G1 water; G2 EHRA 20% w/v and G3 coumaphos 0.2% v/v. Acetylcholinesterase (AChE) activity in R. microplus larvae was determined by a colorimetric assay. The chemical composition of EHRA was accessed through HPLC/MS. Significantly fewer ticks were observed after 24 h on the treated group compared to control group. EHRA significantly inhibited in vitro AChE activity in R. microplus at all tested concentrations. Chlorogenic acid, vanillinic acid, p-coumaric acid, caffeic acid. rutin, quercetin, (-)-epicatechin, 4-hydroxybenzoic acid, quercetin, vanillin, 2,4-dimethoxy-6-methylbenzoic acid, scopoletin and ferulic acid were identified in the extract. The results provided new data for the elucidation of the mechanisms of EHRA acaricide action and to further evaluate the use as a new alternative control agent against R. microplus under in vivo conditions.

N-acetylcysteine improves the inhibitory effect of Quercetin-rich onion extract on HT-29 and HCT-116 colorectal cancer migration and invasion through iNOS suppression.

As colorectal cancer (CRC) usually presents at an advanced stage, it responds poorly to traditional surgery and chemoradiotherapy. Reactive oxygen species (ROSs) are a critical factor in cancer progression. Quercetin, a bioflavonoid derived from onion peel extract, provides great anti-oxidant and anti-cancer potential. Therefore, quercetin in combination with N-Acetylcysteine (NAC), a well-known anti-oxidant and adjuvant agent in cancer-chemotherapeutic drugs, was considered as a way of increasing treatment efficacy. Thus, this study aimed to evaluate the improvement effect of quercetin in combination with NAC in human CRC (HT-29 and HCT-116) cell progression, migration and invasion. Firstly, the effects of quercetin, NAC, and the combination of quercetin and NAC on cellular oxidants and glutathione levels were evaluated. Cell viability, anti-migrative activity and invasive activity were determined by MTT, wound healing, and Matrigel invasion tests, respectively. Then, the proteins involved in cell migration, invasion, and cellular oxidants were investigated. Moreover, the gene expression and overall survival were further validated by the GEPIA2 database. The results reveal that the combination was most effective in decreasing cellular oxidants and increasing glutathione levels, while there was a significant decrease in cancer cell migration and invasion involved in the suppression of iNOS, ICAM-1, and MMP-2 proteins. Furthermore, bioinformatic analysis verified that iNOS, ICAM-1, and MMP-2 were highly expressed in CRC tissue and also associated with a poor prognosis. This study demonstrated that Quercetin has higher efficacy when used in combination with NAC, representing a potential combination agent for anti-cancer drug development.

Mechanism of Quercetin as a Multidrug-resistant Reversing Compound in Oxaliplatin-resistant Gastric-cancer Cell Lines.

Context: Treatment failure due to multidrug resistance (MDR) is a crucial hurdle during chemotherapy. MDR is generally correlated with an upregulation of adenosine triphosphate (ATP)-binding cassette (ABC) transport proteins. Also, aberrant activation of the phosphoinositide 3-kinase (PI3K)/ protein kinase B (Akt) pathway can counteract chemotherapeutic induction. Identification of safe and functioning MDR-reversing compounds is necessary in gastric-cancer therapy. Objective: The study intended to examine the role of Quercetin (Qur) in the mediation of osmotic glycoprotein (P-gp) expression and activity as an ABC transporter in the PI3K/Akt/ P-gp cascade in the oxaliplatin (OxR)-resistant, gastric-cancer cell line KATOIII/OxR. Design: The research team performed a laboratory study. Setting: The study took place at Nantong Haimen People's Hospital. Outcome Measures: The research team: (1) determined the impact of OxR on cell viability after treatment with Qur using trypan blue and "3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide" (MTT) assays; (2) employed a rhodamine 123 (Rh123) assay to detect the activity of P-gp; (3) used quantitative reverse transcription polymerase chain reaction (RT-qPCR) to measure mRNA expression of P-gp; and (4) detected apoptosis using an enzyme-linked immunoassay (ELISA) cell-death assay. Results: Qur: (1) increased the cytotoxicity of OxR; (2) downregulated the expression level and activity of P-gp and reversed MDR through the enhancement of the cytotoxicity of intracellular OxR in KATOIII/OxR cells; and (3) enhanced the apoptosis rate in KATOIII/OxR cells. Conclusions: Qur induced a dramatic reduction in the survival rate of KATOIII/OxR cells and may reverse OxR resistance through a decrease in P-gp expression and activity. These data imply that exposure of KATOIII/OxR cells in the dose-dependent manner to Qur can circumvent MDR by improving the intracellular accumulation of OxR. Qur might provide a new treatment strategy and improve patients' survival after chemotherapy for gastric cancer.

Synthesis of Novel Magnetic Quercetin-Neuropeptide Nanocomposite as a Smart Nano-Drug Shuttle System: Investigation of Its Effect on Behavior, Histopathological Characteristics, and Expression of MAPT and APP Genes in Alzheimer's Disease Rats.

BACKGROUND: Alzheimer's disease (AD) is the most common type of dementia. The drugs introduced for this disease have many side effects and limitations in use, so the production of a suitable herbal medicine to cure AD patients is essential. OBJECTIVE: The aim of this research is to make a magnetic neuropeptide nano shuttle as a targeted carrier for the transfer of quercetin to the brains of AD model rats. METHODS: In this work, a magnetic quercetin-neuropeptide nanocomposite (MQNPN) was fabricated and administered to the rat's brain by the shuttle drug of the Margatoxin scorpion venom neuropeptide, and will be a prospect for targeted drug delivery in AD. The MQNPN has been characterized by FTIR, spectroscopy, FE-SEM, XRD, and VSM. Investigations into the efficacy of MQNPN, MTT, and real Time PCR for MAPT and APP genes expression were performed. After 7 days treatment with Fe3O4 (Ctr) and MQNPN treatment in AD rat, superoxide dismutase activity and quercetin in blood serum and brain was detected. Hematoxylin-Eosin staining was applied for histopathological analysis. RESULTS: Analysis of data showed that MQNPN increased the activity of superoxide dismutase. The histopathology results of the hippocampal region of AD rats also confirmed their improvement after treatment with MQNPN. MQNPN treatment caused a significant decrease in the relative expression of MAPT and APP genes. CONCLUSION: MQNPN is a suitable carrier for the transfer of quercetin to the rat hippocampus, and has a significant effect in reducing AD symptoms in terms of histopathology, behavioral testing, and changing the expression of AD-related genes.

The effect of quercetin on bone healing in an experimental rat model.

OBJECTIVES: This study aims to evaluate the effect of quercetin on fracture healing in an open fracture model in rats. MATERIALS AND METHODS: A total of 80 Wistar-Albino male rats were used in this study. The rats were divided into 10 groups. Daily oral treatment of 100 mg/kg of quercetin dissolved in corn oil were given to four groups, whereas the other four group of control rats were treated with corn oil only. Histopathological and radiological examinations of fracture healing were performed at the end of Weeks 2 and 4 in these rats, while biomechanical and biochemical examinations were performed at the end of Weeks 4 and 6, since harder callus was required. Among the rats in the last two group that were not subjected to the open fracture model, one group was given only quercetin for three weeks and the other for six weeks, and the biochemical markers in the blood were compared between these two groups. Computed tomography images were taken for radiological evaluation. The modified Lane and Sandhu scoring system was used for histological evaluation. The 3-point bending test was performed for biomechanical evaluation. For biochemical evaluation, plasma alkaline phosphatase (ALP), acid phosphatase (AP), total antioxidant status (TAS) and total oxidant status (TOS) levels were measured. RESULTS: Radiologically, there was no significant difference between the early-stage results of quercetin and control groups (p=0.247), while quercetin caused a significant increase in callus tissue in terms of latestage results (p=0.012). Histopathologically, there was no significant difference in the early stage (p=0.584); however, in the late stage, a borderline significant increase was observed in the quercetin group compared to the control group (p=0.091). Biomechanical analysis showed that quercetin significantly increased the fracture strength in the healing bone both in the early period (p=0.036) and in the late period (p=0.027). Among biochemical markers, TOS and AP were found to be significantly decreased in the quercetin group. In the non-operated and quercetin given groups, TAS levels was significantly higher (p=0.001) and AP levels were borderline significantly lower at the end of Week 6 (p=0.063). CONCLUSION: Quercetin did not have a significant effect on bone healing in the early period, but significantly promoted bone healing in the late period in rats. We recommend the use of quercetin, a strong antioxidant, in cases with high oxidative stress and conditions such as diabetes, smoking, and malnutrition which may inhibit fracture union, although further clinical studies are needed to confirm these findings.