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Sample records for quercetin quercetin-gene interaction

  1. Interactions between (+)-catechin and quercetin during their oxidation by nitrite under the conditions simulating the stomach.

    PubMed

    Veljovic-Jovanovic, Sonja; Morina, Filis; Yamauchi, Ryo; Hirota, Sachiko; Takahama, Umeo

    2014-05-28

    When foods that contain catechins and quercetin glycosides are ingested, quercetin glycosides are hydrolyzed to quercetin during mastication by hydrolytic enzymes derived from oral bacteria and the generated quercetin aglycone is mixed with catechins in saliva. The present study deals with the interactions between (+)-catechin and quercetin during their reactions with nitrous acid under the conditions simulating the gastric lumen. Nitrous acid reacted with (+)-catechin producing 6,8-dinitrosocatechin, and quercetin partially suppressed the dinitrosocatechin formation. Nitric oxide, which was produced by not only (+)-catechin/nitrous acid but also quercetin/nitrous acid systems, was used to produce 6,8-dinitrosocatechin. Furthermore, 6,8-dinitrosocatechin was oxidized by nitrous acid to the quinone form. The quinone formation was significantly suppressed by quercetin. Quercetin-dependent suppression of the above reactions accompanied the oxidation of quercetin, which was observed with the formation of 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone. Taking the above results into account, we proposed a possible mechanism of 6,8-dinitrosocatechin formation and discuss the importance of quercetin to prevent the quinone formation from 6,8-dinitrosocatechin in the gastric lumen, taking the interactions between quercetin and catechins into account.

  2. Electrochemical study of quercetin-DNA interactions: part I. Analysis in incubated solutions.

    PubMed

    Oliveira-Brett, Ana Maria; Diculescu, Victor C

    2004-09-01

    The present study aims to investigate the quercetin-deoxyribonucleic acid (DNA) interaction occurring in bulk solution either electrochemically using differential pulse voltammetry or spectrophotometrically, in order to explain the possible DNA-damaging activity of quercetin. A very weak interaction between quercetin and DNA in solution was found to take place. However, since extensive quercetin-induced DNA damage via reaction with Cu(II) has been reported, an electrochemical study of the DNA-Cu(II)-quercetin system in solution was undertaken. The product of DNA interaction with quercetin-Cu(II) complex was observed. Damages to DNA were electrochemically recognized via the increasing of the anodic peaks corresponding to the oxidation of guanosine and adenosine bases and spectrophotometrically via increasing of the 260 nm adsorption band. It was also observed that dsDNA damage produced by the quercetin-Cu(II) complex occurred with time. Control experiments with different mixtures of Cu(II), quercetin, ssDNA, dsDNA or poly[A] were carried out in order to establish a possible mechanism of interaction between DNA and quercetin via Cu(II).

  3. Lack of synergistic interaction between quercetin and catechin in systemic and pulmonary vascular smooth muscle.

    PubMed

    Menendez, Carmen; Jimenez, Rosario; Moreno, Laura; Galindo, Pilar; Cogolludo, Angel; Duarte, Juan; Perez-Vizcaino, Francisco

    2011-05-01

    Due to their ubiquitous distribution, flavonoids from different classes are commonly present together in foods. However, little is known about the interactions between them. The flavonol quercetin and the flavan-3-ol (+)-catechin are among the most abundant flavonoids in the diet. In the present study, we have analysed the interactions between these two flavonoids on vascular function using two pure compounds and mixtures of these flavonoids in 1:0·1, 1:1 or 1:10 proportions. Quercetin induced a more potent concentration-dependent relaxant effect than catechin in the isolated rat aorta, and the isobolographic analysis of the mixtures showed no synergistic or antagonistic effects between them, i.e. their effects were additive. Quercetin was more potent in mesenteric than in pulmonary arteries. Catechin had weak effects in these vessels and did not modify the effects of quercetin. Endothelial dysfunction induced by increased oxidative stress by the superoxide dismutase inhibitor diethyldithiocarbamate was prevented by quercetin, whereas catechin showed a weak effect and the 1:1 mixture an intermediate effect compared with the pure compounds. Quercetin but not catechin showed a pro-oxidant and NO-scavenging effect, which was not prevented by catechin. In conclusion, catechin was less potent than quercetin as a vasodilator, pro-oxidant or to prevent endothelial dysfunction, and there were no synergistic interactions between quercetin and catechin.

  4. Comparative pharmacokinetic interactions of Quercetin and Rutin in rats after oral administration of European patented formulation containing Hipphophae rhamnoides and Co-administration of Quercetin and Rutin.

    PubMed

    Kammalla, Ananth Kumar; Ramasamy, Mohan Kumar; Chintala, Jyothi; Dubey, Govind Prasad; Agrawal, Aruna; Kaliappan, Ilango

    2015-09-01

    Quercetin and Rutin are most common flavone constituents of some herb extracts such as Hippophae rhamnoides L. Inter and intra herb pharmacokinetics interactions of Quercetin and Rutin were investigated in the present study. Pharmacokinetic study was investigated in the two groups of rats (n = 6) for pharmacokinetic interactions between the Quercetin and Rutin (2.5 mg/kg) mixture treated alone with European patented polyherbal formulation containing equivalent weight of the above. The total plasma concentrations of Quercetin and Rutin were determined by liquid chromatography mass spectrometry (LC-MS). A method was developed and validated according to the ICH guidelines. The results of the present study shows that there are great differences in the pharmacokinetics of Quercetin and Rutin when they are administered together and from the polyherbal formulation which will be interacted by many other constituents. The bioavailability of Quercetin was lowered from the polyherbal formulation when compared with the co-administration, whereas the Rutin bioavailability has increased from the polyherbal formulation when compared with the co-administration. The maximum plasma concentration of Quercetin from coadministration and polyherbal formulation was 165.3 ± 31.9 and 90.8 ± 21.4 ng/mL, respectively, whereas in the case of Rutin it was 61.1 ± 29.3 and 121.7 ± 19.2 ng/mL. After polyherbal formulation administration to rats the AUC0-24, AUC0-∞ and AUMC0-∞ of both Quercetin and Rutin significantly increased when compared to co-administration. The above results proved that inter and intra herb pharmacokinetic interactions between Quercetin and Rutin. Possible interactions of the other constituents with hydrolyzing enzymes in the formulation enhances the oral bioavailability of Rutin. Accordingly besides the drug herb interactions, inter and intra herb interaction might be brought into view with the wide use of herbal remedies.

  5. Experimental evidence and molecular modeling of the interaction between hRSV-NS1 and quercetin.

    PubMed

    Gomes, Deriane Elias; Caruso, Ícaro Putinhon; de Araujo, Gabriela Campos; de Lourenço, Isabella Otenio; de Melo, Fernando Alves; Cornélio, Marinônio Lopes; Fossey, Marcelo Andrés; de Souza, Fátima Pereira

    2016-04-01

    Human Respiratory Syncytial Virus is one of the major causes of acute respiratory infections in children, causing bronchiolitis and pneumonia. Non-Structural Protein 1 (NS1) is involved in immune system evasion, a process that contributes to the success of hRSV replication. This protein can act by inhibiting or neutralizing several steps of interferon pathway, as well as by silencing the hRSV ribonucleoproteic complex. There is evidence that quercetin can reduce the infection and/or replication of several viruses, including RSV. The aims of this study include the expression and purification of the NS1 protein besides experimental and computational assays of the NS1-quercetin interaction. CD analysis showed that NS1 secondary structure composition is 30% alpha-helix, 21% beta-sheet, 23% turn and 26% random coils. The melting temperature obtained through DSC analysis was around 56°C. FRET analysis showed a distance of approximately 19Å between the NS1 and quercetin. Fluorescence titration results showed that the dissociation constant of the NS1-quercetin interaction was around 10(-6)M. In thermodynamic analysis, the enthalpy and entropy balanced forces indicated that the NS1-quercetin interaction presented both hydrophobic and electrostatic contributions. The computational results from the molecular modeling for NS1 structure and molecular docking regarding its interaction with quercetin corroborate the experimental data.

  6. Interactions between quercetin and warfarin for albumin binding: A new eye on food/drug interference.

    PubMed

    Di Bari, Lorenzo; Ripoli, Silvia; Pradhan, Sanghamitra; Salvadori, Piero

    2010-06-01

    The interaction between quercetin, a popular antioxidant flavonoid, and human serum albumin (HSA) is investigated and characterized by means of induced circular dichroism and saturation transfer difference NMR. These techiques demonstrate the reversible binding of quercetin to the carrier protein, which is responsible for its dissolution in aqueous medium. Competition experiments with two classical probes for HSA binding sites, namely Ibuprofen and Warfarin (a common anticoagulant coumarin), demonstrate that quercetin has a primary binding site located in the subdomain IIA, where coumarins are hosted. The affinity for this site is large and we found that quercetin may effectively displace warfarin from HSA. This may have relevant consequences in rationalizing the interferences of common dietary compounds and food supplements to anticoagulant treatments.

  7. Clinically relevant interaction between warfarin and scuppernongs, a quercetin containing muscadine grape: continued questions surrounding flavonoid-induced warfarin interactions

    PubMed Central

    Woodward, Christopher J; Deyo, Zachariah M; Donahue, Katrina E; Deal, Allison M; Hawes, Emily M

    2014-01-01

    We present a case of clinically relevant and probable interaction between warfarin and scuppernongs in a 73-year-old woman where ingestion of scuppernongs, a variety of quercetin-containing muscadine grapes, over a period of 2 months was associated with elevations in the International Normalised Ratio to supratherapeutic levels. While muscadine grapes and specifically scuppernongs are found primarily in Southeastern USA, the flavonoid in questionand quercetin is found worldwide as a dietary supplement. PMID:24966255

  8. Clinically relevant interaction between warfarin and scuppernongs, a quercetin containing muscadine grape: continued questions surrounding flavonoid-induced warfarin interactions.

    PubMed

    Woodward, Christopher J; Deyo, Zachariah M; Donahue, Katrina E; Deal, Allison M; Hawes, Emily M

    2014-06-25

    We present a case of clinically relevant and probable interaction between warfarin and scuppernongs in a 73-year-old woman where ingestion of scuppernongs, a variety of quercetin-containing muscadine grapes, over a period of 2 months was associated with elevations in the International Normalised Ratio to supratherapeutic levels. While muscadine grapes and specifically scuppernongs are found primarily in Southeastern USA, the flavonoid in questionand quercetin is found worldwide as a dietary supplement. 2014 BMJ Publishing Group Ltd.

  9. Quercetin interacts with Cry1Ac protein to affect larval growth and survival of Helicoverpa armigera.

    PubMed

    Li, Zhen; Guan, Xiumin; Michaud, J P; Zhang, Qingwen; Liu, Xiaoxia

    2016-07-01

    Bt cotton has been widely planted in China for over a decade to control H. armigera, but field surveys indicate increasing resistance in the pest. It has been speculated that accumulating plant secondary compounds in mature cotton may interact with Bt toxins and affect the toxicity of Bt to H. armigera. Both quercetin, one of the main flavonoids in cotton, and the Bt toxin Cry1Ac protein had significant negative effects on the growth, development and survival of H. armigera when added singly to artificial diet, but their effects were inhibited when added in combination. Quercetin was antagonistic to Cry1Ac toxicity at all tested concentrations. The accumulation of quercetin might be one factor contributing to the reduced toxicity of mature Bt cotton plants to H. armigera, and could partially explain the reduced efficacy of Cry1Ac in controlling this pest in the field. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  10. Quercetin, a Natural Flavonoid Interacts with DNA, Arrests Cell Cycle and Causes Tumor Regression by Activating Mitochondrial Pathway of Apoptosis

    PubMed Central

    Srivastava, Shikha; Somasagara, Ranganatha R.; Hegde, Mahesh; Nishana, Mayilaadumveettil; Tadi, Satish Kumar; Srivastava, Mrinal; Choudhary, Bibha; Raghavan, Sathees C.

    2016-01-01

    Naturally occurring compounds are considered as attractive candidates for cancer treatment and prevention. Quercetin and ellagic acid are naturally occurring flavonoids abundantly seen in several fruits and vegetables. In the present study, we evaluate and compare antitumor efficacies of quercetin and ellagic acid in animal models and cancer cell lines in a comprehensive manner. We found that quercetin induced cytotoxicity in leukemic cells in a dose-dependent manner, while ellagic acid showed only limited toxicity. Besides leukemic cells, quercetin also induced cytotoxicity in breast cancer cells, however, its effect on normal cells was limited or none. Further, quercetin caused S phase arrest during cell cycle progression in tested cancer cells. Quercetin induced tumor regression in mice at a concentration 3-fold lower than ellagic acid. Importantly, administration of quercetin lead to ~5 fold increase in the life span in tumor bearing mice compared to that of untreated controls. Further, we found that quercetin interacts with DNA directly, and could be one of the mechanisms for inducing apoptosis in both, cancer cell lines and tumor tissues by activating the intrinsic pathway. Thus, our data suggests that quercetin can be further explored for its potential to be used in cancer therapeutics and combination therapy. PMID:27068577

  11. Quercetin targets the interaction of calcineurin with LxVP-type motifs in immunosuppression

    PubMed Central

    Zhao, Yane; Zhang, Jin; Shi, Xiaoyu; Li, Jing; Wang, Rui; Song, Ruiwen; Wei, Qun; Cai, Huaibin; Luo, Jing

    2016-01-01

    Calcineurin (CN) is a unique calcium/calmodulin (CaM)-activated serine/threonine phosphatase. To perform its diverse biological functions, CN communicates with many substrates and other proteins. In the physiological activation of T cells, CN acts through transcriptional factors belonging to the NFAT family and other transcriptional effectors. The classic immunosuppressive drug cyclosporin A (CsA) can bind to cyclophilin (CyP) and compete with CN for the NFAT LxVP motif. CsA has debilitating side effects, including nephrotoxicity, hypertension and tremor. It is desirable to develop alternative immunosuppressive agents. To this end, we first tested the interactions between CN and the LxVP-type substrates, including endogenous regulators of calcineurin (RCAN1) and NFAT. Interestingly, we found that quercetin, the primary dietary flavonol, can inhibit the activity of CN and significantly disrupt the associations between CN and its LxVP-type substrates. We then validated the inhibitory effects of quercetin on the CN-NFAT interactions in cell-based assays. Further, quercetin also shows dose-dependent suppression of cytokine gene expression in mouse spleen cells. These data raise the possibility that the interactions of CN with its LxVP-type substrates are potential targets for immunosuppressive agents. PMID:27109380

  12. Fluorescence lifetime and UV-Vis spectroscopy to evaluate the interactions between quercetin and its yeast microcapsule.

    PubMed

    Pham-Hoang, Bao-Ngoc; Winckler, Pascale; Waché, Yves

    2017-09-09

    Quercetin is a fragile bioactive compound. Several works have tried to preserve it by encapsulation but the form of encapsulation (mono- or supra-molecular structure, tautomeric form), though important for stability and bioavailability, remains unknown. The present work aims at developing a fluorescence lifetime technique to evaluate the structure of quercetin during encapsulation in a vector capsule that has already proven efficiency, yeast cells. Molecular stabilization was observed during a four-month storage period. The time-correlated single-photon counting (TCSPC) technique was used to evaluate the interaction between quercetin molecules and the yeast capsule. The various tautomeric forms, as identified by UV-Vis spectroscopy, resulted in various lifetimes in TCSPC, although they varied also with the buffer environment. Quercetin in buffer exhibited a three-to-four longer long time after 24 h (changing from 6-7 to 18-23 ns), suggesting an aggregation of molecules. In yeast microcapsules, the long-time population exhibited a longer lifetime (around 27 ns) from the beginning and concerned about 20% of molecules compared to dispersed quercetin. This shows that lifetime analysis can show the monomolecular instability of quercetin in buffer and the presence of interactions between quercetin molecules and their microcapsules. This article is protected by copyright. All rights reserved.

  13. A combined spectroscopic, molecular docking and molecular dynamic simulation study on the interaction of quercetin with β-casein nanoparticles.

    PubMed

    Mehranfar, Fahimeh; Bordbar, Abdol-Khalegh; Parastar, Hadi

    2013-10-05

    The interaction of quercetin with β-casein nanoparticle micelle was studied at various temperatures in order to do a complete thermodynamic and molecular analysis on the binding process. The results of fluorescence studies showed the possibility of fluorescence energy transfer between excited tryptophan and quercetin. The determined values of critical transfers distance and the mean distance of ligand from Trp-143 residues in β-casein micelle represents a non-radiative energy transfer mechanism for quenching and the existence of a significant interaction between this flavonoid and β-casein nanoparticle. The equilibrium binding of quercetin with β-casein micelle at different temperatures was studied by using UV-Vis absorption spectroscopy. The chemometric analysis (principal component analysis (PCA) and multivariate curve resolution-alternating least squares (MCR-ALS) methods) on spectrophotometric data revealed the existence of two components in solution (quercetin and β-casein-quercetin complex) and resolved their pure concentration and spectral profiles. This information let us to calculate the equilibrium binding constant at various temperatures and the relevant thermodynamic parameters of interaction (enthalpy, entropy and Gibbs free energy) with low uncertainty. The negative values of entropy and enthalpy changes represent the predominate role of hydrogen binding and van der Waals interactions in the binding process. Docking calculations showed the probable binding site of quercetin is located in the hydrophobic core of β-casein where the quercetin molecule is lined by hydrophobic residues and make five hydrogen bonds and several van der Waals contacts with them. Moreover, molecular dynamic (MD) simulation results suggested that this flavonoid can interact with β-casein, without affecting the secondary structure of β-casein. Simulations, molecular docking and experimental data reciprocally supported each other. Copyright © 2013 Elsevier B.V. All

  14. Quercetin, an in vitro inhibitor of CYP3A, does not contribute to the interaction between nifedipine and grapefruit juice.

    PubMed Central

    Rashid, J; McKinstry, C; Renwick, A G; Dirnhuber, M; Waller, D G; George, C F

    1993-01-01

    Quercetin, a flavonoid present in various fruits, is a potent in vitro inhibitor of CYP3A. Its role in the reported interaction between grapefruit juice and nifedipine has been determined in vivo in humans. Eight healthy volunteers were given in random order 10 mg nifedipine orally, either alone or with 200 ml double strength grapefruit juice, or with 400 mg quercetin. The area under the plasma concentration-time curve (AUC) for nifedipine with grapefruit juice (mean 320 ng ml(-1) h) was increased significantly (P < 0.01) compared with the AUC when nifedipine was given alone (mean 218 ng ml(-1) h). The time to peak plasma concentration for nifedipine with grapefruit juice (1.5 h) was also increased (P < 0.05) compared with control (0.5 h) suggesting delayed absorption. Although quercetin delayed the time to peak nifedipine concentration (1.3 h) it did not alter the AUC of either the parent drug (mean 209 ng ml(-1) h) or its first-pass metabolite. The results suggest that quercetin does not contribute to the effects of grapefruit juice (which contains <10 mg of quercetin 200 ml(-1)) on the metabolism of nifedipine. Oral doses of quercetin, similar to those possible from the ingestion of other fruits such as strawberries, do not produce in vivo inhibition of CYP3A mediated metabolism of nifedipine. PMID:12959295

  15. Spectroscopic studies on the interaction of quercetin-terbium(III) complex with calf thymus DNA.

    PubMed

    Dehghan, Gholamreza; Dolatabadi, Jafar Ezzati Nazhad; Jouyban, Abolghasem; Zeynali, Karim Asadpour; Ahmadi, Seyed Mojtaba; Kashanian, Soheila

    2011-03-01

    The interaction of native calf thymus DNA (CT-DNA) with quercetin-terbium(III) [Q-Tb(III)] complex at physiological pH was monitored by UV absorption spectrophotometry, circular dichroism, fluorescence spectroscopy, and viscosimetric techniques. The complex displays binding properties to the CT-DNA and was found to interact with CT-DNA through outside binding, demonstrated by a hypochromic effect of Q-Tb(III) on the UV spectra of CT-DNA and the calculated association constants (K). Also, decrease in the specific viscosity of CT-DNA, decrease in the fluorescence intensity of Q-Tb(III) solutions in the presence of increasing amounts of CT-DNA, and detectable changes in the circular dichroism spectrum of CT-DNA are other evidences to indicate that Q-Tb(III) complex interact with CT-DNA through outside binding.

  16. A lucid build-up of nanostructured curcumin, quercetin and their interaction with DNA.

    PubMed

    Rajasekaran, Marichamy; Annaraj, Jamespandi

    2014-07-01

    Nanostructured phyto-drugs such as curcumin and quercetin were prepared by simple sonochemical method and studied for their bio-activities. FT-IR spectra indicate that the chemical structures of these nanostructured drugs are identical with their commercially available microcrystalline counterparts. Scanning Electron Microscopic (SEM) analysis reveals that the curcumin and quercetin, form as nanocube and nanoneedle like structures respectively. These nanocrystalline drugs have enhanced solubility in neutral aqueous medium at room temperature and thus exhibit better bioavailability than their commercially available microcrystalline form. Their DNA interactions and the observed binding constants were investigated through UV-vis spectral technique. Nanocurcumin, due to its small size, exhibits significantly high DNA binding constant (1.2 x 10(6) M(-1)). The voltammetric and CD spectral changes observed for the nanocurcumin reveal its deep penetration into the core of the DNA through the minor grooves, where it forms H-bonds with the floor nitrogen/oxygen atoms of the DNA bases.

  17. Spectrometric and voltammetric studies of the interaction between quercetin and bovine serum albumin using warfarin as site marker with the aid of chemometrics

    NASA Astrophysics Data System (ADS)

    Ni, Yongnian; Zhang, Xia; Kokot, Serge

    2009-01-01

    The interaction of quercetin, which is a bioflavonoid, with bovine serum albumin (BSA) was investigated under pseudo-physiological conditions by the application of UV-vis spectrometry, spectrofluorimetry and cyclic voltammetry (CV). These studies indicated a cooperative interaction between the quercetin-BSA complex and warfarin, which produced a ternary complex, quercetin-BSA-warfarin. It was found that both quercetin and warfarin were located in site I. However, the spectra of these three components overlapped and the chemometrics method - multivariate curve resolution-alternating least squares (MCR-ALS) was applied to resolve the spectra. The resolved spectra of quercetin-BSA and warfarin agreed well with their measured spectra, and importantly, the spectrum of the quercetin-BSA-warfarin complex was extracted. These results allowed the rationalization of the behaviour of the overlapping spectra. At lower concentrations ([warfarin] < 1 × 10 -5 mol L -1), most of the site marker reacted with the quercetin-BSA, but free warfarin was present at higher concentrations. Interestingly, the ratio between quercetin-BSA and warfarin was found to be 1:2, suggesting a quercetin-BSA-(warfarin) 2 complex, and the estimated equilibrium constant was 1.4 × 10 11 M -2. The results suggest that at low concentrations, warfarin binds at the high-affinity sites (HAS), while low-affinity binding sites (LAS) are occupied at higher concentrations.

  18. Interactions of quercetin and its lanthane complex with double stranded DNA/RNA and single stranded RNA: spectrophotometric sensing of poly G.

    PubMed

    Marinić, Mirna; Piantanida, Ivo; Rusak, Gordana; Zinić, Mladen

    2006-02-01

    Spectrophotometric titrations revealed that stability of the quercetin/double stranded (ds) DNA or double stranded (ds) RNA non-covalent complexes is significantly higher compared to the quercetin/ss-RNA complexes. This observation can easily be correlated with the significantly larger aromatic surface of base pairs compared to single nucleobases, and it is in good agreement with other experimental data pointing toward intercalative binding mode of quercetin. Fluorescence increase of quercetin induced by ds-RNA is significantly stronger than observed for ds-DNA, offering usage of quercetin as the ds-RNA selective fluorescent probe. Also, addition of poly G yielded more than order of magnitude stronger changes in UV/visible and fluorescence spectrum of quercetin compared to the changes upon addition of poly A and poly U revealing possible usage of quercetin as a powerful spectroscopic probe for poly G sequences. Stability and stoichiometry of lanthane(III)/quercetin complexes in physiologically relevant aqueous media was determined. The interactions of (LaQ)(3+) with double stranded DNA and RNA were significantly different compared to the free quercetin, revealing increase of complex stability and thus significant impact of La(III) in binding of (LaQ)(3+) to polynucleotides. Similar results were observed for interactions of (LaQ)(3+) with single stranded RNA.

  19. Interactions of gallic acid, resveratrol, quercetin and aspirin at the platelet cyclooxygenase-1 level. Functional and modelling studies.

    PubMed

    Crescente, Marilena; Jessen, Gisela; Momi, Stefania; Höltje, Hans-Dieter; Gresele, Paolo; Cerletti, Chiara; de Gaetano, Giovanni

    2009-08-01

    While resveratrol and quercetin possess antiplatelet activity, little is known on the effect of gallic acid on platelets. We studied the interactions of these three different polyphenols among themselves and with aspirin, at the level of platelet cyclooxygenase-1 (COX-1). Both functional (in vitro and in vivo) and molecular modelling approaches were used. All three polyphenols showed comparable antioxidant activity (arachidonic acid [AA]-induced intraplatelet ROS production); however, resveratrol and quercetin, but not gallic acid, inhibited AA-induced platelet aggregation. Gallic acid, similarly to salicylic acid, the major aspirin metabolite, prevented inhibition of AA-induced platelet function by aspirin but, at variance with salicylic acid, also prevented inhibition by the other two polyphenols. Molecular modelling studies, performed by in silico docking the polyphenols into the crystal structure of COX-1, suggested that all compounds form stable complexes into the COX-1 channel, with slightly different but functionally relevant interaction geometries. Experiments in mice showed that gallic acid administered before aspirin, resveratrol or quercetin fully prevented their inhibitory effect on serum TxB(2). Finally, a mixture of resveratrol, quercetin and gallic acid, at relative concentrations similar to those contained in most red wines, did not inhibit platelet aggregation, but potentiated sub-inhibitory concentrations of aspirin. Gallic acid interactions with other polyphenols or aspirin at the level of platelet COX-1 might partly explain the complex, and possibly contrasting, effects of wine and other components of the Mediterranean diet on platelets and on the pharmacologic effect of low-dose aspirin.

  20. Biophysical characterization of the interaction between M2-1 protein of hRSV and quercetin.

    PubMed

    Teixeira, Thiago Salem Pançonato; Caruso, Ícaro Putinhon; Lopes, Bruno Rafael Pereira; Regasini, Luis Octávio; Toledo, Karina Alves de; Fossey, Marcelo Andrés; Souza, Fátima Pereira de

    2017-02-01

    hRSV is the major causative agent of acute respiratory infections. Among its eleven proteins, M2-1 is a transcription antiterminator, making it an interesting target for antivirals. Quercetin is a flavonol which inhibits some virus infectivity and replication. In the present work, the M2-1 gene was cloned, expressed and the protein was purified. Thermal stability and secondary structure were analyzed by circular dichroism and the interaction with Quercetin was evaluated by fluorescence spectroscopy. Molecular docking experiments were performed to understand this mechanism of interaction. The purified protein is mainly composed of α-helix, with a melting temperature of 328.6K (≈55°C). M2-1 titration with Quercetin showed it interacts with two sites, one with a strong constant association K1 (site 1≈1.5×10(6)M(-1)) by electrostatic interactions, and another with a weak constant association K2 (site 2≈1.1×10(5)M(-1)) by a hydrophobic interaction. Ligand's docking shows it interacts with the N-terminus face in a more polar pocket and, between the domains of oligomerization and RNA and P protein interaction, in a more hydrophobic pocket, as predicted by experimental data. Therefore, we postulated this ligand could be interacting with important domains of the protein, avoiding viral replication and budding. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Quercetin inhibits the 5-hydroxytryptamine type 3 receptor-mediated ion current by interacting with pre-transmembrane domain I.

    PubMed

    Lee, Byung-Hwan; Jeong, Sang-Min; Jung, Sang-Min; Lee, Jun-Ho; Kim, Jong-Hoon; Yoon, In-Soo; Lee, Joon-Hee; Choi, Sun-Hye; Lee, Sang-Mok; Chang, Choon-Gon; Kim, Hyung-Chun; Han, YeSun; Paik, Hyun-Dong; Kim, Yangmee; Nah, Seung-Yeol

    2005-08-31

    The flavonoid, quercetin, is a low molecular weight substance found in apple, tomato and other fruit. Besides its antioxidative effect, quercetin, like other flavonoids, has a wide range of neuropharmacological actions including analgesia, and motility, sleep, anticonvulsant, sedative and anxiolytic effects. In the present study, we investigated its effect on mouse 5-hydroxytryptamine type 3 (5-HT3A) receptor channel activity, which is involved in pain transmission, analgesia, vomiting, and mood disorders. The 5-HT3A receptor was expressed in Xenopus oocytes, and the current was measured with the two-electrode voltage clamp technique. In oocytes injected with 5-HT3A receptor cRNA, quercetin inhibited the 5-HT-induced inward peak current (I(5-HT)) with an IC50 of 64.7 +/- 2.2 microM. Inhibition was competitive and voltage-independent. Point mutations of pre-transmembrane domain 1 (pre-TM1) such as R222T and R222A, but not R222D, R222E and R222K, abolished inhibition, indicating that quercetin interacts with the pre-TM1 of the 5-HT3A receptor.

  2. Fluorescence quenching study of quercetin interaction with bovine milk xanthine oxidase

    NASA Astrophysics Data System (ADS)

    Rasoulzadeh, Farzaneh; Jabary, Hamideh Nadjarpour; Naseri, Abdolhossein; Rashidi, Mohammad-Reza

    2009-02-01

    Quercetin is a natural flavonoid with many important therapeutic properties. The interaction of this polyphenolic compound bovine milk xanthine oxidase as one of its major target proteins was studied using fluorescence quenching method for the first time. It was found that the fluorescence quenching of xanthine oxidase occurs through a static mechanism. The results revealed the presence of a single binding site on xanthine oxidase with the binding constant value equals to 1.153 × 10 4 l mol -1 at 310 K and pH 7.4. The thermodynamic parameters were also calculated at different temperatures. The enthalpy and entropy changes were found as -10.661 kJ mol -1 and +43.321 J mol -1 K -1 indicating that both hydrogen binding and hydrophobic are involved in the interaction of this polyphenolic natural compound with xanthine oxidase. The results may provide a ground for further studies with different flavonoids to find a safe alternative for allopurinol, the only xanthine oxidase inhibitor with clinical application.

  3. Quercetin and allopurinol reduce liver thioredoxin-interacting protein to alleviate inflammation and lipid accumulation in diabetic rats

    PubMed Central

    Wang, Wei; Wang, Chuang; Ding, Xiao-Qin; Pan, Ying; Gu, Ting-Ting; Wang, Ming-Xing; Liu, Yang-Liu; Wang, Fu-Meng; Wang, Shui-Juan; Kong, Ling-Dong

    2013-01-01

    Background and Purpose Thioredoxin-interacting protein (TXNIP), a regulator of cellular oxidative stress, has been associated with activation of NOD-like receptor 3 (NLRP3) inflammasome, inflammation and lipid metabolism, suggesting it has a role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) in diabetes. In this study we investigated whether TXNIP is involved in type 1 diabetes-associated NAFLD and whether antioxidants, quercetin and allopurinol, alleviate NAFLD by targeting TXNIP. Experimental Approach Diabetes was induced in male Sprague-Dawley rats by a single i.p. injection of 55 mg·kg−1 streptozotocin. Quercetin and allopurinol were given p.o. to diabetic rats for 7 weeks. Hepatic function, oxidative stress, inflammation and lipid levels were determined. Rat BRL-3A and human HepG2 cells were exposed to high glucose (30 mM) in the presence and absence of antioxidants, TXNIP siRNA transfection or caspase-1 inhibitor, Ac-YVAD-CMK. Key Results Quercetin and allopurinol significantly inhibited the TXNIP overexpression, activation of NLRP3 inflammasome, down-regulation of PPARα and up-regulation of sterol regulatory element binding protein-1c (SREBP-1c), SREBP-2, fatty acid synthase and liver X receptor α, as well as elevation of ROS and IL-1β in diabetic rat liver. These effects were confirmed in hepatocytes in vitro and it was further shown that TXNIP down-regulation contributed to the suppression of NLRP3 inflammasome activation, inflammation and changes in PPARα and SREBPs. Conclusions and Implications Inhibition of hepatic TXNIP by quercetin and allopurinol contributes to the reduction in liver inflammation and lipid accumulation under hyperglycaemic conditions. The targeting of hepatic TXNIP by quercetin and allopurinol may have therapeutic implications for prevention of type 1 diabetes-associated NAFLD. PMID:23647015

  4. Mapping the interactions and bioactivity of quercetin-(2-hydroxypropyl)-β-cyclodextrin complex.

    PubMed

    Kellici, Tahsin F; Chatziathanasiadou, Maria V; Diamantis, Dimitris; Chatzikonstantinou, Alexandra V; Andreadelis, Ioannis; Christodoulou, Eirini; Valsami, Georgia; Mavromoustakos, Thomas; Tzakos, Andreas G

    2016-09-10

    Natural products have served as a rich source for drug discovery and development. In the last decade their fruitful integration in the drug discovery pipeline declined due to their reduced bioavailability, mainly attributed to their poor aqueous solubility. We synthesized a quercetin (QUE)-(2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) complex that enabled amplification of its solubility and in the same time retained its bioactivity in T24 human bladder cancer cell line. The stability of the complex and the molecular basis of the interactions developed in this host-guest complex were assayed by incorporating an array of analytical techniques and Molecular Dynamics (MD) experiments. 2D DOSY NMR experiment revealed that the diffusion coefficient of free HP-β-CD was 3.55×10(-10)m(2)s(-1) while that of QUE-HP-β-CD inclusion complex 3.09×10(-10)m(2)s(-1), indicating the formation of a complex. Solid and liquid high resolution NMR spectroscopy data showed that the most pronounced differences in chemical shifts at carbons and protons correspondingly during complexation occur in the aromatic ring Α (bearing the two phenolic hydroxyl groups meta to each other). The chemical shift differences in the aromatic ring Β (bearing the two phenolic hydroxyl groups ortho to each other) were less pronounced. The MD results confirmed the experimental data. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Effects of Caffeic Acid and Quercetin on In Vitro Permeability, Metabolism and In Vivo Pharmacokinetics of Melatonin in Rats: Potential for Herb-Drug Interaction.

    PubMed

    Jana, Snehasis; Rastogi, Himanshu

    2017-01-09

    Melatonin is a popular dietary supplement and also considered as pharmaceutical product for sleep disorders. Caffeic acid and quercetin are widely distributed in leafy vegetables, fruits, tea extract, and both are used as natural antioxidant. There is an immense concern for health researchers to study the herb/food-drug interactions of melatonin. It is mainly metabolized by CYP1A2 in human so that herbs/foods containing cytochrome P450 (CYP) inhibitors can affect pharmacokinetics of melatonin. By considering pharmacokinetic aspects, the present study was undertaken to evaluate the effects of caffeic acid and quercetin on Caco-2 cells permeability, metabolism, CYP1A inhibition in vitro assay systems and a single dose pharmacokinetics of melatonin in vivo rats. The effects of caffeic acid and quercetin on melatonin permeability were tested in Caco-2 cells. Metabolic stability and CYP1A activity were investigated in rat liver microsomes (RLMs) using probe substrates (melatonin/phenacetin in vitro). Melatonin and phenacetin were incubated in RLMs with or without caffeic acid and quercetin, and the IC50 values were determined. The pharmacokinetics of melatonin conducted in rats after a single dose (15 mg/kg) pre-treatment with caffeic acid, quercetin and caffeic acid plus quercetin followed by oral dose of melatonin at 5 mg/kg. Analysis of all samples was with LC-MS/MS. Caffeic acid and quercetin did not alter Caco-2 permeability of melatonin in apical to basolateral direction and vice versa. Melatonin was metabolized in rat liver microsomes, which was inhibited by both caffeic acid and quercetin through CYP1A. The concomitant oral administration of melatonin along with 15 mg/kg of caffeic acid or quercetin or caffeic acid plus quercetin significantly (p < 0.05) increased the AUC0-t of melatonin by 30.0, 66.7 and 114.0%, respectively. The apparent oral rat plasma clearance (CL/F) of melatonin also decreased significantly (p < 0.05) by 28.78, 47.87 and 50% in

  6. Ellagic acid and quercetin interact synergistically with resveratrol in the induction of apoptosis and cause transient cell cycle arrest in human leukemia cells.

    PubMed

    Mertens-Talcott, Susanne U; Percival, Susan S

    2005-02-10

    Anticarcinogenic effects of polyphenolic compounds in fruits and vegetables are well established. Although polyphenols naturally occur as combinations, little information is available regarding possible synergistic or antagonistic biochemical interactions between compounds. Identifying potential interactions between polyphenols may provide information regarding the efficiency of polyphenol-containing foods in cancer prevention. The objective of this study was to investigate the interactions of ellagic acid and quercetin with resveratrol, polyphenols which occur in muscadine grapes, with the hypothesis that the selected polyphenols would interact synergistically in the induction of apoptosis and reduction of cell growth in human leukemia cells (MOLT-4). To test this hypothesis, alterations in cell cycle kinetics, proliferation, and apoptosis (caspase-3 activity) were examined after incubation with ellagic acid, quercetin, and resveratrol as single compounds and in combination. Results showed a more than additive interaction for the combination of ellagic acid with resveratrol and furthermore, significant alterations in cell cycle kinetics induced by single compounds and combinations were observed. An isobolographic analysis was performed to assess the apparent synergistic interaction for the combinations of ellagic acid with resveratrol and quercetin with resveratrol in the induction of caspase 3 activity, confirming a synergistic interaction with a combination index of 0.64 for the combination of ellagic acid and resveratrol and 0.68 for quercetin and resveratrol. Results indicate that the anticarcinogenic potential of foods containing polyphenols may not be based on the effects of individual compounds, but may involve a synergistic enhancement of the anticancer effects.

  7. Interaction of quercetin and its metabolites with warfarin: Displacement of warfarin from serum albumin and inhibition of CYP2C9 enzyme.

    PubMed

    Poór, Miklós; Boda, Gabriella; Needs, Paul W; Kroon, Paul A; Lemli, Beáta; Bencsik, Tímea

    2017-04-01

    Flavonoids are ubiquitous molecules in nature with manifold pharmacological effects. Flavonoids interact with several proteins, and thus potentially interfere with the pharmacokinetics of various drugs. Though much is known about the protein binding characteristics of flavonoid aglycones, the behaviour of their metabolites, which are extensively formed in the human body has received little attention. In this study, the interactions of the flavonoid aglycone quercetin and its main metabolites with the albumin binding of the oral anticoagulant warfarin were investigated by fluorescence spectroscopy and ultrafiltration. Furthermore, the inhibitory effects of these flavonoids on CYP2C9 enzyme were tested because the metabolic elimination of warfarin is catalysed principally by this enzyme. Herein, we demonstrate that each tested flavonoid metabolite can bind to human serum albumin (HSA) with high affinity, some with similar or even higher affinity than quercetin itself. Quercetin metabolites are able to strongly displace warfarin from HSA suggesting that high quercetin doses can strongly interfere with warfarin therapy. On the other hand, tested flavonoids showed no or weaker inhibition of CYP2C9 compared to warfarin, making it very unlikely that quercetin or its metabolites can significantly inhibit the CYP2C9-mediated inactivation of warfarin.

  8. Inhibitory effect of quercetin on matrix metalloproteinase 9 activity molecular mechanism and structure-activity relationship of the flavonoid-enzyme interaction.

    PubMed

    Saragusti, Alejandra C; Ortega, María G; Cabrera, José L; Estrin, Darío A; Marti, Marcelo A; Chiabrando, Gustavo A

    2010-10-10

    Epidemiological studies have demonstrated an inverse association between the consumption of flavonoid-rich diets and the risk of atherosclerosis. In addition, an increased activity of the matrix metalloproteinase 9 (MMP-9) has been implicated in the development and progression of atherosclerotic lesions. Even though the relationship between flavonoid chemical structure and the inhibitory property on MMP activity has been established, the molecular mechanisms of this inhibition are still unknown. Herein, we first evaluated the inhibitory effect of quercetin on MMP-9 activity by zymography and a fluorescent gelatin dequenching assay, secondly we determined the most probable sites and modes of quercetin interaction with the MMP-9 catalytic domain by using molecular modelling techniques, and finally, we investigated the structure-activity relationship of the inhibitory effect of flavonoids on MMP-9 activity. We show that quercetin inhibited MMP-9 activity with an IC(50) value of 22 microM. By using docking and molecular dynamics simulations, it was shown that quercetin interacted in the S1' subsite of the MMP-9 active site. Moreover, the structure-activity relationship analysis demonstrated that flavonoid R(3)(')-OH and R(4)(')-OH substitutions were relevant to the inhibitory property against MMP-9 activity. In conclusion, our data constitute the first evidence about the quercetin and MMP-9 interaction, suggesting a mechanism to explain the inhibitory effect of the flavonoid on the enzymatic activity of MMP-9, which provides an additional molecular target for the cardioprotective activity of quercetin. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Towards an Understanding of the Low Bioavailability of Quercetin: A Study of Its Interaction with Intestinal Lipids.

    PubMed

    Rich, Gillian T; Buchweitz, Maria; Winterbone, Mark S; Kroon, Paul A; Wilde, Peter J

    2017-02-05

    We have studied the uptake of quercetin aglycone into CaCo-2/TC7 cells in the presence and absence of mixed micelles that are present in the human small intestine. The micelles inhibited the transport of quercetin into the cells. To gain an understanding of why this is the case we examined the solubilisation of quercetin in micelles of differing composition and into pure lipid phases. We did this by using the environmental sensitivity of quercetin's UV-visible absorption spectra and measurement of free quercetin by filtration of the micellar solutions. The nature of the micelles was also studied by pyrene fluorescence. We found that the partitioning of quercetin into simple bile salt micelles was low and for mixed micelles was inhibited by increasing the bile salt concentration. The affinity of quercetin decreased in the order egg phosphatidylcholine (PC) = lysoPC > mixed micelles > bile salts. These results, together with the innate properties of quercetin, contribute to an understanding of the low bioavailability of quercetin.

  10. Bioactivity In Vitro of Quercetin Glycoside Obtained in Beauveria bassiana Culture and Its Interaction with Liposome Membranes.

    PubMed

    Strugała, Paulina; Tronina, Tomasz; Huszcza, Ewa; Gabrielska, Janina

    2017-09-11

    Quercetin (Q) was used as substrate for regioselective glycosylation at the C-7 position catalyzed by Beauveria bassiana AM278 strain. As a result the glycoside quercetin 7-O-β-d-(4″-O-methyl)glucopyranoside (Q 7-MeGlu) was formed. The goal of the studies was to determine the anti-oxidative (liposome membrane protection against free radicals IC50(Q 7-MeGlu) = 5.47 and IC50(Q) = 4.49 µM) and anti-inflammatory (COX-1 and COX-2 enzymes activity inhibition) properties of Q 7-MeGlu as compared to Q. Every attempt was made to clarify the antioxidant activity of these molecules, which are able to interact with egg phosphatidylcholine liposomes, using a fluorometric method (by applying the probes MC540, TMA-DPH and DPH). The results indicated that Q 7-MeGlu and Q are responsible for increasing the packing order, mainly in the hydrophilic but also in hydrophobic regions of the membrane (Q > Q 7-MeGlu). These observations, confirmed by a ¹H-NMR method, are key to understanding their antioxidant activity which is probably caused by the stabilizing effect on the lipid membranes. The results showed that Q 7-MeGlu and Q have ability to quench the human serum albumin (HSA) intrinsic fluorescence through a static quenching mechanism. The results of thermodynamic parameters indicated that the process of formation complexes between studied molecules and HSA was spontaneous and caused through Van der Waals interactions and hydrogen bonding.

  11. Towards an Understanding of the Low Bioavailability of Quercetin: A Study of Its Interaction with Intestinal Lipids

    PubMed Central

    Rich, Gillian T.; Buchweitz, Maria; Winterbone, Mark S.; Kroon, Paul A.; Wilde, Peter J.

    2017-01-01

    We have studied the uptake of quercetin aglycone into CaCo-2/TC7 cells in the presence and absence of mixed micelles that are present in the human small intestine. The micelles inhibited the transport of quercetin into the cells. To gain an understanding of why this is the case we examined the solubilisation of quercetin in micelles of differing composition and into pure lipid phases. We did this by using the environmental sensitivity of quercetin’s UV-visible absorption spectra and measurement of free quercetin by filtration of the micellar solutions. The nature of the micelles was also studied by pyrene fluorescence. We found that the partitioning of quercetin into simple bile salt micelles was low and for mixed micelles was inhibited by increasing the bile salt concentration. The affinity of quercetin decreased in the order egg phosphatidylcholine (PC) = lysoPC > mixed micelles > bile salts. These results, together with the innate properties of quercetin, contribute to an understanding of the low bioavailability of quercetin. PMID:28165426

  12. Investigation of the interaction between quercetin and human serum albumin by multiple spectra, electrochemical impedance spectra and molecular modeling.

    PubMed

    Dai, Jie; Zou, Ting; Wang, Li; Zhang, Yezhong; Liu, Yi

    2014-12-01

    Quercetin (Qu), a flavonoid compound, exists widely in the human diet and exhibits a variety of pharmacological activities. This work is aimed at studying the effect of Qu on the bioactive protein, human serum albumin (HSA) under simulated biophysical conditions. Multiple spectroscopic methods (including fluorescence and circular dichroism), electrochemical impedance spectra (EIS) and molecular modeling were employed to investigate the interaction between Qu and HSA. The fluorescence quenching and EIS experimental results showed that the fluorescence quenching of HSA was caused by formation of a Qu-HSA complex in the ground state, which belonged to the static quenching mechanism. Based on the calculated thermodynamic parameters, it concluded that the interaction was a spontaneous process and hydrogen bonds combined with van der Waal's forces played a major role in stabilizing the Qu-HSA complex. Molecular modeling results demonstrated that several amino acids participated in the binding process and the formed Qu-HSA complex was stabilized by H-bonding network at site I in sub-domain IIA, which was further confirmed by the site marker competitive experiments. The evidence from circular dichroism (CD) indicated that the secondary structure and microenvironment of HSA were changed. Alterations in the conformation of HSA were observed with a reduction in the amount of α helix from 59.9% (free HSA) to 56% (Qu-HSA complex), indicating a slight unfolding of the protein polypeptides.

  13. Metabolic interactions between acetaminophen (paracetamol) and two flavonoids, luteolin and quercetin, through in-vitro inhibition studies.

    PubMed

    Cao, Lei; Kwara, Awewura; Greenblatt, David J

    2017-09-05

    Excessive exposure to acetaminophen (APAP, paracetamol) can cause liver injury through formation of a reactive metabolite that depletes hepatic glutathione and causes hepatocellular oxidative stress and damage. Generation of this metabolite is mediated by Cytochrome-P450 (CYP) isoforms, mainly CYP2E1. A number of naturally occurring flavonoids can mitigate APAP-induced hepatotoxicity in experimental animal models. Our objective was to determine the mechanism of these protective effects and to evaluate possible human applicability. Two flavonoids, luteolin and quercetin, were evaluated as potential inhibitors of eight human CYP isoforms, of six UDP-glucuronosyltransferase (UGT) isoforms and of APAP glucuronidation and sulfation. The experimental model was based on in-vitro metabolism by human liver microsomes, using isoform-specific substrates. Luteolin and quercetin inhibited human CYP isoforms to varying degrees, with greatest potency towards CYP1A2 and CYP2C8. However, 50% inhibitory concentrations (IC50 values) were generally in the micromolar range. UGT isoforms were minimally inhibited. Both luteolin and quercetin inhibited APAP sulfation but not glucuronidation. Inhibition of human CYP activity by luteolin and quercetin occurred with IC50 values exceeding customary in-vivo human exposure with tolerable supplemental doses of these compounds. The findings indicate that luteolin and quercetin are not likely to be of clinical value for preventing or treating APAP-induced hepatotoxicity. © 2017 Royal Pharmaceutical Society.

  14. Exploiting Noncovalent Interactions in an Imine-Based Covalent Organic Framework for Quercetin Delivery.

    PubMed

    Vyas, Vijay S; Vishwakarma, Medhavi; Moudrakovski, Igor; Haase, Frederik; Savasci, Gökcen; Ochsenfeld, Christian; Spatz, Joachim P; Lotsch, Bettina V

    2016-10-01

    Covalent organic frameworks (COFs) are a new class of nanoporous polymeric vector showing promise as drug-delivery vehicles with high loading capacity and biocompatibility. The interaction between the carrier and the cargo is specifically tailored on a molecular level by H-bonding. Cell-proliferation studies indicate higher efficacy of the drug in cancer cells by nanocarrier delivery mediated by the COF.

  15. Quercetin induces cytochrome-c release and ROS accumulation to promote apoptosis and arrest the cell cycle in G2/M, in cervical carcinoma: signal cascade and drug-DNA interaction.

    PubMed

    Bishayee, K; Ghosh, S; Mukherjee, A; Sadhukhan, R; Mondal, J; Khuda-Bukhsh, A R

    2013-04-01

    Small aromatic compounds like flavonoids can intercalate with DNA molecules bringing about conformational changes leading to reduced replication and transcription. Here, we have examined one dietary flavonoid, quercetin (found in many fruit and vegetables), for possible anti-cancer effects, on HeLa cells originally derived from a case of human cervical cancer. By circular dichroism spectroscopy we tested whether quercetin effectively interacted with DNA to bring about conformational changes that would strongly inhibit proliferation and migration of the HeLa cells. Cytotoxic effects of quercetin on cancer/normal cells, if any, were determined by MTT assay and such depolarization of mitochondrial membrane potential, as a consequence of quercetin treatment, and accumulation of reactive oxygen species (ROS) also were studied, by FACS analysis and expression profiles of different anti- and pro-apoptotic genes and their products were determined. Quercetin intercalated with calf thymus cell DNA and HeLa cell DNA and inhibition of anti-apoptotic AKT and Bcl-2 expression were observed. Levels of mitochondrial cytochrome-c were elevated and depolarization of mitochondrial membrane potential occurred with increase of ROS; upregulation of expression of p53 and caspase-3 activity were also noted. These alterations in signalling proteins and externalization of phosphotidyl serine residues were involved with initiation of apoptosis. Reduced AKT expression suggested reduction in cell proliferation and metastasis potential, with arrest of the cell cycle at G2/M. Quercetin would have potential for use in cervical cancer chemotherapy. © 2013 Blackwell Publishing Ltd.

  16. Differential effects of quercetin glycosides on GABAC receptor channel activity.

    PubMed

    Kim, Hyeon-Joong; Lee, Byung-Hwan; Choi, Sun-Hye; Jung, Seok-Won; Kim, Hyun-Sook; Lee, Joon-Hee; Hwang, Sung-Hee; Pyo, Mi-Kyung; Kim, Hyoung-Chun; Nah, Seung-Yeol

    2015-01-01

    Quercetin, a representative flavonoid, is a compound of low molecular weight found in various colored plants and vegetables. Quercetin shows a wide range of neuropharmacological activities. In fact, quercetin naturally exists as monomer-(quercetin-3-O-rhamnoside) (Rham1), dimer-(Rutin), or trimer-glycosides [quercetin-3-(2(G)-rhamnosylrutinoside)] (Rham2) at carbon-3 in fruits and vegetables. The carbohydrate components are removed after ingestion into gastrointestinal systems. The role of the glycosides attached to quercetin in the regulation of γ-aminobutyric acid class C (GABAC) receptor channel activity has not been determined. In the present study, we examined the effects of quercetin glycosides on GABAC receptor channel activity by expressing human GABAC alone in Xenopus oocytes using a two-electrode voltage clamp technique and also compared the effects of quercetin glycosides with quercetin. We found that GABA-induced inward current (I GABA ) was inhibited by quercetin or quercetin glycosides. The inhibitory effects of quercetin and its glycosides on I GABA were concentration-dependent and reversible in the order of Rutin ≈ quercetin ≈ Rham 1 > Rham 2. The inhibitory effects of quercetin and its glycosides on I GABA were noncompetitive and membrane voltage-insensitive. These results indicate that quercetin and its glycosides regulate GABAC receptor channel activity through interaction with a different site from that of GABA, and that the number of carbohydrate attached to quercetin might play an important role in the regulation of GABAC receptor channel activity.

  17. Quercetin, Inflammation and Immunity.

    PubMed

    Li, Yao; Yao, Jiaying; Han, Chunyan; Yang, Jiaxin; Chaudhry, Maria Tabassum; Wang, Shengnan; Liu, Hongnan; Yin, Yulong

    2016-03-15

    In vitro and some animal models have shown that quercetin, a polyphenol derived from plants, has a wide range of biological actions including anti-carcinogenic, anti-inflammatory and antiviral activities; as well as attenuating lipid peroxidation, platelet aggregation and capillary permeability. This review focuses on the physicochemical properties, dietary sources, absorption, bioavailability and metabolism of quercetin, especially main effects of quercetin on inflammation and immune function. According to the results obtained both in vitro and in vivo, good perspectives have been opened for quercetin. Nevertheless, further studies are needed to better characterize the mechanisms of action underlying the beneficial effects of quercetin on inflammation and immunity.

  18. Quercetin, Inflammation and Immunity

    PubMed Central

    Li, Yao; Yao, Jiaying; Han, Chunyan; Yang, Jiaxin; Chaudhry, Maria Tabassum; Wang, Shengnan; Liu, Hongnan; Yin, Yulong

    2016-01-01

    In vitro and some animal models have shown that quercetin, a polyphenol derived from plants, has a wide range of biological actions including anti-carcinogenic, anti-inflammatory and antiviral activities; as well as attenuating lipid peroxidation, platelet aggregation and capillary permeability. This review focuses on the physicochemical properties, dietary sources, absorption, bioavailability and metabolism of quercetin, especially main effects of quercetin on inflammation and immune function. According to the results obtained both in vitro and in vivo, good perspectives have been opened for quercetin. Nevertheless, further studies are needed to better characterize the mechanisms of action underlying the beneficial effects of quercetin on inflammation and immunity. PMID:26999194

  19. The quercetin paradox

    SciTech Connect

    Boots, Agnes W. . E-mail: a.boots@farmaco.unimaas.nl; Li, Hui; Schins, Roel P.F.; Duffin, Rodger; Heemskerk, Johan W.M.; Bast, Aalt; Haenen, Guido R.M.M.

    2007-07-01

    Free radical scavenging antioxidants, such as quercetin, are chemically converted into oxidation products when they protect against free radicals. The main oxidation product of quercetin, however, displays a high reactivity towards thiols, which can lead to the loss of protein function. The quercetin paradox is that in the process of offering protection, quercetin is converted into a potential toxic product. In the present study, this paradox is evaluated using rat lung epithelial (RLE) cells. It was found that quercetin efficiently protects against H{sub 2}O{sub 2}-induced DNA damage in RLE cells, but this damage is swapped for a reduction in GSH level, an increase in LDH leakage as well as an increase of the cytosolic free calcium concentration. To our knowledge, this is the first study that indicates that the quercetin paradox, i.e. the exchange of damage caused by quercetin and its metabolites, also occurs in living lung cells. Following depletion of GSH in the cells by BSO pre-treatment, this quercetin paradox becomes more pronounced, confirming that the formation of thiol reactive quercetin metabolites is involved in the quercetin paradox. The quercetin paradox in living cells implies that the anti-oxidant directs oxidative damage selectively to thiol arylation. Apparently, the potential toxicity of metabolites formed during the actual antioxidant activity of free radical scavengers should be considered in antioxidant supplementation.

  20. The Antidiabetic Potential of Quercetin: Underlying Mechanisms.

    PubMed

    Eid, Hoda M; Haddad, Pierre S

    2017-01-01

    The dramatic increase in modern lifestyle diseases such as cancer, cardiovascular diseases and diabetes has renewed researchers' interest to explore nature as a source of novel therapeutic agents. Flavonoids are a large group of polyphenols that are widely present in the human diet. They have shown promising therapeutic activities against a wide variety of ailments. One of the most widely distributed and most extensively studied flavonoid is the flavonol quercetin. Its powerful antioxidant and anti-inflammatory activities are well documented and are thought to play a role in treating and protecting against diseases including diabetes, cancer, neurodegenerative and cardiovascular diseases. The purpose of this review is to shed light on quercetin therapeutic potential as an antidiabetic agent. Quercetin was reported to interact with many molecular targets in small intestine, pancreas, skeletal muscle, adipose tissue and liver to control whole-body glucose homeostasis. Mechanisms of action of quercetin are pleiotropic and involve the inhibition of intestinal glucose absorption, insulin secretory and insulin-sensitizing activities as well as improved glucose utilization in peripheral tissues. Initial studies suggested poor bioavailability of quercetin. However, recent reports have shown that quercetin was detected in the plasma after food or supplements consumption and has a long half-life in human body. Despite the wealth of in vitro and in vivo results supporting the antidiabetic potential of quercetin, its efficacy in diabetic human subjects is yet to be explored. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  1. Cocrystals of kaempferol, quercetin and myricetin with 4,4‧-bipyridine: Crystal structures, analyses of intermolecular interactions and antibacterial properties

    NASA Astrophysics Data System (ADS)

    Zhang, Yu-Nan; Yin, He-Mei; Zhang, Yu; Zhang, Da-Jun; Su, Xin; Kuang, Hai-Xue

    2017-02-01

    With an aim to explore the interactions of Osbnd H⋯N between hydroxyl moiety of the flavonoids and the pyridyl ring of N-containing aromatic amines, three flavonols with varying B-ring-hydroxyl groups (kaempferol, quercetin, and myricetin) were selected to combine with 4,4‧-bipyridine. As a result, three new cocrystals of flavonols were obtained with a solution evaporation approach. These three cocrystals were characterized by single crystal X-ray diffraction, XPRD, IR and NMR methods. The resulting cocrystals were kaempferol: 4,4‧-bipyridine (2:1) (KAE·BPY·2H2O), quercetin: 4,4‧-bipyridine (1:1.5) (QUE·BPY), and myricetin: 4,4‧-bipyridine (1:2) (MYR·BPY·H2O). Structural analyses show that an array of hydrogen bonds and π-π stacking interactions interconnect the molecules to form a two-dimensional (2D) supramolecular layer in KAE·BPY·2H2O, QUE·BPY, and MYR·BPY·H2O. In the three cocrystals, they present as three different synthons-ⅠR88(58), Ⅳ R44(42) and, Ⅶ R66(29) with 4,4‧-bipyridine, respectively-which may yield a strategy for constructing the supramolecule. Cocrystals of flavonols combined with N-containing aromatic amines, 7-OH, B-ring-hydroxyl number and/or the location of the flavonols to play a significant part in extending the dimensionality of the cocrystals. The resulting motif formation and crystal packing in these flavonols cocrystals has combined with N-containing aromatic amines. Additionally, the antibacterial properties of the three cocrystals against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) have been investigated.

  2. In-vitro anti-proliferative and anti-oxidant activity of galangin, fisetin and quercetin: role of localization and intermolecular interaction in model membrane.

    PubMed

    Sinha, Ragini; Srivastava, Sudha; Joshi, Akshada; Joshi, Urmila J; Govil, Girjesh

    2014-05-22

    Flavonols are an important class of naturally occurring molecules and are known for their pharmacological activity. The activity is associated with the ability of flavonols to influence membrane-dependent processes. We have investigated the in-vitro anti-proliferative and anti-oxidant activity of galangin (GLN), fisetin (FTN) and quercetin (QTN), which possess variable number of phenolic hydroxyl groups. An attempt has been made to correlate the biological activity of these molecules with their interaction and localization in dipalmitoyl phosphatidyl choline (DPPC) bilayers, using differential dcanning calorimetry (DSC) and nuclear magnetic resonance (NMR) methods. Results indicate that GLN interacts to the alkyl chains of the lipid bilayer involving hydrophobic interactions. FTN and QTN interact with head region and sn-1-glycero region involving hydrogen bonding. Ring current induced chemical shifts of lipid protons, due to intermolecular interaction indicate that GLN acquires a parallel orientation with respect to the bilayer normal whereas FTN and QTN resume a mixed orientation. The membrane binding constants of these molecules are in the order GLN > QTN > FTN. It has been shown that the number and position of hydroxyl groups in these molecules play an important role in membrane binding and thereby in biological activity.

  3. Binding of fluphenazine with human serum albumin in the presence of rutin and quercetin: An evaluation of food-drug interaction by spectroscopic techniques.

    PubMed

    Jing, Jiao-Jiao; Liu, Bin; Wang, Xin; Wang, Xin; He, Ling-Ling; Guo, Xue-Yuan; Xu, Ming-Ling; Li, Qian-Yu; Gao, Bo; Dong, Bo-Yang

    2017-09-01

    The interactions between human serum albumin (HSA) and fluphenazine (FPZ) in the presence or absence of rutin or quercetin were studied by fluorescence, absorption and circular dichroism (CD) spectroscopy and molecular modeling. The results showed that the fluorescence quenching mechanism was static quenching by the formation of an HSA-FPZ complex. Entropy change (ΔS(0) ) and enthalpy change (ΔH(0) ) values were 68.42 J/(mol⋅K) and -4.637 kJ/mol, respectively, which indicated that hydrophobic interactions and hydrogen bonds played major roles in the acting forces. The interaction process was spontaneous because the Gibbs free energy change (ΔG(0) ) values were negative. The results of competitive experiments demonstrated that FPZ was mainly located within HSA site I (sub-domain IIA). Molecular docking results were in agreement with the experimental conclusions of the thermodynamic parameters and competition experiments. Competitive binding to HSA between flavonoids and FPZ decreased the association constants and increased the binding distances of FPZ binding to HSA. The results of absorption, synchronous fluorescence, three-dimensional fluorescence, and CD spectra showed that the binding of FPZ to HSA caused conformational changes in HSA and simultaneous effects of FPZ and flavonoids induced further HSA conformational changes. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Structure-spectrophotometric selectivity relationship in interactions of quercetin related flavonoids with double stranded and single stranded RNA

    NASA Astrophysics Data System (ADS)

    Piantanida, Ivo; Mašić, Lozika; Rusak, Gordana

    2009-04-01

    Interactions of five flavonoids with dsRNA and single stranded ssRNA were studied by UV/vis titrations. The results obtained supported the intercalative binding mode as a dominant interaction of studied flavonoids with dsRNA as well as major interaction with ssRNA. Furthermore, changes of the UV/vis spectra of flavonoids induced by addition of poly G or poly C, respectively, are significantly stronger than changes induced by double stranded poly G-poly C, pointing to essential role of the free poly G or poly C sequence (not hydrogen bonded in double helix). Exclusively poly G caused significant batochromic shift of the UV/vis maxima of all studied flavonoids, whereby the intensity of batochromic shift is nicely correlated to the number of OH groups of flavonoid. Unlikely to poly G, addition of poly A and poly U induced measurable changes only in the UV/vis spectra of flavonoids characterised by no OH (galangin) or three OH groups (myricetin) on the phenyl part of the molecule. Consequently, flavonoids with one- or two-OH groups on the phenyl part of the molecule (luteolin, fisetin, kaempferol) specifically differentiate between poly A, poly U (negligible changes in the UV/Vis spectra) and poly G (strong changes in the UV/Vis spectra) as well as poly C (moderate changes in the UV/Vis spectra).

  5. Decavanadate, decaniobate, tungstate and molybdate interactions with sarcoplasmic reticulum Ca(2+)-ATPase: quercetin prevents cysteine oxidation by vanadate but does not reverse ATPase inhibition.

    PubMed

    Fraqueza, Gil; Batista de Carvalho, Luís A E; Marques, M Paula M; Maia, Luisa; Ohlin, C André; Casey, William H; Aureliano, Manuel

    2012-11-07

    Recently we demonstrated that the decavanadate (V(10)) ion is a stronger Ca(2+)-ATPase inhibitor than other oxometalates, such as the isoelectronic and isostructural decaniobate ion, and the tungstate and molybdate monomer ions, and that it binds to this protein with a 1 : 1 stoichiometry. The V(10) interaction is not affected by any of the protein conformations that occur during the process of calcium translocation (i.e. E1, E1P, E2 and E2P) (Fraqueza et al., J. Inorg. Biochem., 2012). In the present study, we further explore this subject, and we can now show that the decaniobate ion, [Nb(10) = Nb(10)O(28)](6-), is a useful tool in deducing the interaction and the non-competitive Ca(2+)-ATPase inhibition by the decavanadate ion [V(10) = V(10)O(28)](6-). Moreover, decavanadate and vanadate induce protein cysteine oxidation whereas no effects were detected for the decaniobate, tungstate or molybdate ions. The presence of the antioxidant quercetin prevents cysteine oxidation, but not ATPase inhibition, by vanadate or decavanadate. Definitive V(IV) EPR spectra were observed for decavanadate in the presence of sarcoplasmic reticulum Ca(2+)-ATPase, indicating a vanadate reduction at some stage of the protein interaction. Raman spectroscopy clearly shows that the protein conformation changes that are induced by V(10), Nb(10) and vanadate are different from the ones induced by molybdate and tungstate monomer ions. Here, Mo and W cause changes similar to those by phosphate, yielding changes similar to the E1P protein conformation. The putative reduction of vanadium(V) to vanadium(IV) and the non-competitive binding of the V(10) and Nb(10) decametalates may explain the differences in the Raman spectra compared to those seen in the presence of molybdate or tungstate. Putting it all together, we suggest that the ability of V(10) to inhibit the Ca(2+)-ATPase may be at least in part due to the process of vanadate reduction and associated protein cysteine oxidation. These

  6. Quercetin suppresses insulin receptor signaling through inhibition of the insulin ligand–receptor binding and therefore impairs cancer cell proliferation

    SciTech Connect

    Wang, Feng; Yang, Yong

    2014-10-03

    Graphical abstract: - Highlights: • Quercetin inhibits insulin ligand–receptor interactions. • Quercetin reduces downstream insulin receptor signaling. • Quercetin blocks insulin induced glucose uptake. • Quercetin suppresses insulin stimulated cancer cell proliferation and tumor growth. - Abstract: Although the flavonoid quercetin is known to inhibit activation of insulin receptor signaling, the inhibitory mechanism is largely unknown. In this study, we demonstrate that quercetin suppresses insulin induced dimerization of the insulin receptor (IR) through interfering with ligand–receptor interactions, which reduces the phosphorylation of IR and Akt. This inhibitory effect further inhibits insulin stimulated glucose uptake due to decreased cell membrane translocation of glucose transporter 4 (GLUT4), resulting in impaired cancer cell proliferation. The effect of quercetin in inhibiting tumor growth was also evident in an in vivo model, indicating a potential future application for quercetin in the treatment of cancers.

  7. Quercetin Affects Erythropoiesis and Heart Mitochondrial Function in Mice

    PubMed Central

    Ruiz, Paula A.; Barreto, Marlen; Elorza, Alvaro A.

    2015-01-01

    Quercetin, a dietary flavonoid used as a food supplement, showed powerful antioxidant effects in different cellular models. However, recent in vitro and in vivo studies in mammals have suggested a prooxidant effect of quercetin and described an interaction with mitochondria causing an increase in O2 ∙− production, a decrease in ATP levels, and impairment of respiratory chain in liver tissue. Therefore, because of its dual actions, we studied the effect of quercetin in vivo to analyze heart mitochondrial function and erythropoiesis. Mice were injected with 50 mg/kg of quercetin for 15 days. Treatment with quercetin decreased body weight, serum insulin, and ceruloplasmin levels as compared with untreated mice. Along with an impaired antioxidant capacity in plasma, quercetin-treated mice showed a significant delay on erythropoiesis progression. Heart mitochondrial function was also impaired displaying more protein oxidation and less activity for IV, respectively, than no-treated mice. In addition, a significant reduction in the protein expression levels of Mitofusin 2 and Voltage-Dependent Anion Carrier was observed. All these results suggest that quercetin affects erythropoiesis and mitochondrial function and then its potential use as a dietary supplement should be reexamined. PMID:26106459

  8. Microbial Transformation of Quercetin by Bacillus cereus

    PubMed Central

    Rao, Koppaka V.; Weisner, Nghe T.

    1981-01-01

    Biotransformation of quercetin was examined with a number of bacterial cultures. In the presence of a bacterial culture (Bacillus cereus), quercetin was transformed into two crystalline products, identified as protocatechuic acid and quercetin-3-glucoside (isoquercitrin). PMID:16345844

  9. [Study of quantum-pharmacological chemical characteristics of quercetin].

    PubMed

    Zahorodnyĭ, M I

    2007-01-01

    It was established in the previous studies that quercetin prevented the development and caused faster regression of ulcers, petechia and anabroses in rats, which were induced by diclofenac taking. In the group of patients taking diclofenac together with quercetin, the ulcers and dyspeptic events were less found. The application of quercetin normalizes the function and metabolism of cartilage tissue of rabbits with an experimental osteoarthrosis and in patients with osteoartrosis. Quantum-chemical properties of molecule quercetin were studied using the methods of molecular mechanics MM+ and ab initio 6-31G*, and also semiempirical method. The following indices were investigated: distance between atoms (A), the distribution of electronic density of only external valency electrons, distribution of electrostatic potential; common energy of the exertion of molecule (kkal/mmol); binding energy (kkal/mmol); electron energy (kkal/mmol); energy of nucleus-nucleus interaction (kkal/mmol); formation heat (kkal/mmol); atomic charge (eB); value of the dipole moment of molecule (D); localization and energy of highest occupied orbital (HOMO) and the lowest unoccupied (LUMO) molecular orbital (eB) of quercetin miolecule; the value of absolute rigidity of chemical structure of bioflavonoid. It was shown, that bioflavonoid quercetin belongs to mild reagents, has nucleophilic properties, can react with alkaline, unsaturated and aromatic compounds,. Polar substitutes in the quercetine molecule influence on the distribution of superficial valency electrons and localization of HOMO and LUMO. The energy value of quercetin LUMO enables us to refer quercetine to the reducing agent and it is illustrated by antioxidant properties of this medicine.

  10. Quercetin Represses Apolipoprotein B Expression by Inhibiting the Transcriptional Activity of C/EBPβ

    PubMed Central

    Inoue, Jun; Sato, Ryuichiro

    2015-01-01

    Quercetin is one of the most abundant polyphenolic flavonoids found in fruits and vegetables and has anti-oxidative and anti-obesity effects. Because the small intestine is a major absorptive organ of dietary nutrients, it is likely that highly concentrated food constituents, including polyphenols, are present in the small intestinal epithelial cells, suggesting that food factors may have a profound effect in this tissue. To identify novel targets of quercetin in the intestinal enterocytes, mRNA profiling using human intestinal epithelial Caco-2 cells was performed. We found that mRNA levels of some apolipoproteins, particularly apolipoprotein B (apoB), are downregulated in the presence of quercetin. On the exposure of Caco-2 cells to quercetin, both mRNA and protein levels of apoB were decreased. Promoter analysis of the human apoB revealed that quercetin response element is localized at the 5′-proximal promoter region, which contains a conserved CCAAT enhancer-binding protein (C/EBP)-response element. We found that quercetin reduces the promoter activity of apoB, driven by the enforced expression of C/EBPβ. Quercetin had no effect on either mRNA or protein levels of C/EBPβ. In contrast, we found that quercetin inhibits the transcriptional activity of C/EBPβ but not its recruitment to the apoB promoter. On the exposure of Caco-2 cells to quercetin 3-O-glucuronide, which is in a cell-impermeable form, no notable change in apoB mRNA was observed, suggesting an intracellular action of quercetin. In vitro interaction experiments using quercetin-conjugated beads revealed that quercetin binds to C/EBPβ. Our results describe a novel regulatory mechanism of transcription of apolipoprotein genes by quercetin in the intestinal enterocytes. PMID:25875015

  11. Quercetin 3,7-dimethyl ether: a vasorelaxant flavonoid isolated from Croton schiedeanus Schlecht.

    PubMed

    Guerrero, M F; Puebla, P; Carrón, R; Martín, M L; San Román, L

    2002-10-01

    The vasorelaxant profile of quercetin 3,7-dimethyl ether, a flavonoid isolated from Croton schiedeanus Schlecht (Euphorbiaceae), was assessed in aortic rings isolated from Wistar rats. To gain insight into its structure-activity relationship, we compared this substance with quercetin 3,4',7-trimethyl ether (ayanin), another flavonoid isolated from this plant, quercetin 3,3',4',7-tetramethyl ether, a flavonoid synthesized by us, and quercetin. In addition we examined the interaction of quercetin 3,7-dimethyl ether with the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway. According to their pEC50 values (concentration producing a 50% inhibition of the maximal contractile response) to phenylephrine-induced precontraction in rat isolated aorta, the potency order was quercetin 3,7-dimethyl ether > quercetin > quercetin 3,4',7-trimethyl ether > quercetin 3,3',4',7-tetramethyl ether (4.70+/-0.18; 3.96+/-0.07; 3.64+/-0.02; 3.11+/-0.16). The relaxant effect of quercetin 3,7-dimethyl ether was significantly decreased by the removal of endothelium as well as by methylene blue, an inhibitor of guanylyl cyclase, and by N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME), an NO-synthase inhibitor. Therefore, quercetin 3,7-dimethyl ether has a NO/cGMP pathway-related profile, with increased vasorelaxant activity due to hydroxylation at positions 3 and 4 of the B ring. In addition, methylation at positions 3 and 7 with respect to quercetin of the C and A rings, respectively, seems to further enhance the vasorelaxant activity of quercetin 3,7-dimethyl ether.

  12. Binding, stability, and antioxidant activity of quercetin with soy protein isolate particles.

    PubMed

    Wang, Yufang; Wang, Xiaoyong

    2015-12-01

    This work is to study the potential of particles fabricated from soy protein isolate (SPI) as a protective carrier for quercetin. When the concentration of SPI particles increases from 0 to 0.35 g/L, quercetin gives a gradually increased fluorescence intensity and fluorescence anisotropy. The addition of quercetin can highly quench the intrinsic fluorescence of SPI particles. These results are explained in terms of the binding of quercetin to the hydrophobic pockets of SPI particles mainly through the hydrophobic force together with the hydrogen bonding. The small difference in the binding constants at 25 and 40 °C suggests the structural stability of SPI particles. The relative changes in values of Gibbs energy, enthalpy, and entropy indicate that the binding of quercetin with SPI particles is spontaneous and hydrophobic interaction is the major force. Furthermore, SPI particles are superior to native SPI for improving the stability and radical scavenging activity of quercetin.

  13. Quercetin solubilisation in bile salts: A comparison with sodium dodecyl sulphate.

    PubMed

    Buchweitz, Maria; Kroon, Paul A; Rich, Gillian T; Wilde, Peter J

    2016-11-15

    To understand the bioaccessibility of the flavonoid quercetin we studied its interaction with bile salt micelles. The environmental sensitivity of quercetin's UV-visible absorption spectrum gave information about quercetin partitioning. Two quercetin absorption peaks gave complementary information: Peak A (240-280nm) on the intermicellar phase and Peak B (340-440nm) on the micellar phase. Thus, by altering pH, we showed that only non-ionised quercetin partitions into micelles. We validated our interpretation by studying quercetin's interaction with SDS micelles. Pyrene fluorescence and the quercetin UV-visible spectra show that the adsorption site for pyrene and quercetin in bile salt micelles is more hydrophobic than that for SDS micelles. Also, both quercetin and pyrene reported a higher critical micelle concentration for bile salts than for SDS. Our method of using a flavonoid as an intrinsic probe, is generally applicable to other lipophilic bioactives, whenever they have observable environmental dependent properties. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. Discriminative protection against hydroxyl and superoxide anion radicals by quercetin in human leucocytes in vitro.

    PubMed

    Wilms, Lonneke C; Kleinjans, Jos C S; Moonen, Edwin J C; Briedé, Jacob J

    2008-03-01

    Antioxidants play a vital role in the cellular protection against oxidative damage. Quercetin is a well-investigated antioxidant and known to be able to protect against cellular oxidative DNA damage. In this study, we tried to relate the protection by quercetin pre-treatment against oxidative DNA damage in human leucocytes in vitro to the interaction of quercetin in solution with hydroxyl and superoxide anion radicals as measured by electron spin resonance (ESR) spectrometry, using DMPO as a spin trap. Further, scavenging capacity of quercetin-treated leucocytes in vitro was evaluated by ESR spectrometry. Quercetin appears capable of protecting human leucocytes against oxidative DNA damage caused by hydrogen peroxide in a dose-dependent manner. The protection of leucocytes against superoxides is ambiguous. Incubation concentrations of quercetin (1, 10, and 50 microM) reduced levels of superoxide-induced oxidative DNA damage, while at 100 microM the amount of damage was increased. These results are supported by ESR-findings on quercetin in solution, also showing a prooxidant effect at 100 microM. ESR spectroscopy showed rate constant values for the reaction kinetics of quercetin in lowering iron-dependent hydroxyl radical formation and NADH-dependent superoxide anion formation of respectively 3.2 x 10(12)M(-1)s(-1) and 1.1 x 10(4)M(-1)s(-1). This shows that quercetin is a more potent inhibitor of hydroxyl radical formation than a scavenger of superoxide anions.

  15. Quercetin-3-rutinoside Inhibits Protein Disulfide Isomerase by Binding to Its b′x Domain*

    PubMed Central

    Lin, Lin; Gopal, Srila; Sharda, Anish; Passam, Freda; Bowley, Sheryl R.; Stopa, Jack; Xue, Guangpu; Yuan, Cai; Furie, Barbara C.; Flaumenhaft, Robert; Huang, Mingdong; Furie, Bruce

    2015-01-01

    Quercetin-3-rutinoside inhibits thrombus formation in a mouse model by inhibiting extracellular protein disulfide isomerase (PDI), an enzyme required for platelet thrombus formation and fibrin generation. Prior studies have identified PDI as a potential target for novel antithrombotic agents. Using a fluorescence enhancement-based assay and isothermal calorimetry, we show that quercetin-3-rutinoside directly binds to the b′ domain of PDI with a 1:1 stoichiometry. The binding of quercetin-3-rutinoside to PDI induces a more compact conformation and restricts the conformational flexibility of PDI, as revealed by small angle x-ray scattering. The binding sites of quercetin-3-rutinoside to PDI were determined by studying its interaction with isolated fragments of PDI. Quercetin-3-rutinoside binds to the b′x domain of PDI. The infusion of the b′x fragment of PDI rescued thrombus formation that was inhibited by quercetin-3-rutinoside in a mouse thrombosis model. This b′x fragment does not possess reductase activity and, in the absence of quercetin-3-rutinoside, does not affect thrombus formation in vivo. The isolated b′ domain of PDI has potential as an antidote to reverse the antithrombotic effect of quercetin-3-rutinoside by binding and neutralizing quercetin-3-rutinoside. PMID:26240139

  16. Quercetin-3-rutinoside Inhibits Protein Disulfide Isomerase by Binding to Its b'x Domain.

    PubMed

    Lin, Lin; Gopal, Srila; Sharda, Anish; Passam, Freda; Bowley, Sheryl R; Stopa, Jack; Xue, Guangpu; Yuan, Cai; Furie, Barbara C; Flaumenhaft, Robert; Huang, Mingdong; Furie, Bruce

    2015-09-25

    Quercetin-3-rutinoside inhibits thrombus formation in a mouse model by inhibiting extracellular protein disulfide isomerase (PDI), an enzyme required for platelet thrombus formation and fibrin generation. Prior studies have identified PDI as a potential target for novel antithrombotic agents. Using a fluorescence enhancement-based assay and isothermal calorimetry, we show that quercetin-3-rutinoside directly binds to the b' domain of PDI with a 1:1 stoichiometry. The binding of quercetin-3-rutinoside to PDI induces a more compact conformation and restricts the conformational flexibility of PDI, as revealed by small angle x-ray scattering. The binding sites of quercetin-3-rutinoside to PDI were determined by studying its interaction with isolated fragments of PDI. Quercetin-3-rutinoside binds to the b'x domain of PDI. The infusion of the b'x fragment of PDI rescued thrombus formation that was inhibited by quercetin-3-rutinoside in a mouse thrombosis model. This b'x fragment does not possess reductase activity and, in the absence of quercetin-3-rutinoside, does not affect thrombus formation in vivo. The isolated b' domain of PDI has potential as an antidote to reverse the antithrombotic effect of quercetin-3-rutinoside by binding and neutralizing quercetin-3-rutinoside. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Influence of quercetin and nanohydroxyapatite modifications of decellularized goat-lung scaffold for bone regeneration.

    PubMed

    Gupta, Sweta K; Kumar, Ritesh; Mishra, Narayan C

    2017-02-01

    In the present study, goat-lung scaffold was fabricated by decellularization of lung tissue and verified for complete cell removal by DNA quantification, DAPI and H&E staining. The scaffold was then modified by crosslinking with quercetin and nanohydroxyapatite (nHAp), and characterized to evaluate the suitability of quercetin-crosslinked nHAp-modified scaffold for regeneration of bone tissue. The crosslinking chemistry between quercetin and decellularized scaffold was established theoretically by AutoDock Vina program (in silico docking study), which predicted multiple intermolecular hydrogen bonding interactions between quercetin and decellularized scaffold, and FTIR spectroscopy analysis also proved the same. From MTT assay and SEM studies, it was found that the quercetin-crosslinked nHAp-modified decellularized scaffold encouraged better growth and proliferation of bone-marrow derived mesenchymal stem cells (BMMSCs) in comparison to unmodified decellularized scaffold, quercetin-crosslinked decellularized scaffold and nHAp-modified decellularized scaffold. Alkaline Phosphatase (ALP) assay results showed highest expression of ALP over quercetin-crosslinked nHAp-modified scaffold among all the tested scaffolds (unmodified decellularized scaffold, quercetin-crosslinked decellularized scaffold and nHAp-modified decellularized scaffold) indicating that quercetin and nHAp is very much efficient in stimulating the differentiation of BMMSCs into osteoblast cells. Alizarin red test quantified in vitro mineralization (calcium deposits), and increased expression of alizarin red over quercetin-crosslinked nHAp-modified scaffold indicating better stimulation of osteogenesis in BMMSCs. The above findings suggest that quercetin-crosslinked nHAp-modified decellularized goat-lung scaffold provides biomimetic bone-like microenvironment for BMMSCs to differentiate into osteoblast and could be applied as a potential promising biomaterial for bone regeneration.

  18. Effects of dietary quercetin on performance and cytochrome P450 expression of the cotton bollworm, Helicoverpa armigera.

    PubMed

    Liu, D; Yuan, Y; Li, M; Qiu, X

    2015-12-01

    Quercetin is ubiquitous in terrestrial plants. The cotton bollworm Helicoverpa armigera as a highly polyphagous insect has caused severe crop losses. Until now, interactions between this pest and quercetin are poorly understood at the biochemical and molecular levels. In this study, we investigated the in vivo effects of quercetin on performance of cotton bollworm and on cytochrome P450 (P450) expression. Deleterious effects of quercetin on the performance of the cotton bollworm, including growth, survival, pupation and adult emergence were observed after oral administration of 3 and 10 mg g(-1) quercetin to larvae since the third instar, whereas no significant toxic effect was found at 0.1 mg g(-1) quercetin treatment. Piperonyl butoxide treatment enhanced the toxicity of quercetin. In vitro metabolism studies showed that quercetin was rapidly transformed by gut enzymes of fifth instar larvae of the cotton bollworm. qRT-PCR results revealed that the effect of quercetin on P450 expression was tissue- and dose-specific. Quercetin regulated P450 expression in a mild manner, and it could serve as P450 inducer (CYP337B1, CYP6B6) or repressor (CYP337B1, CYP6B7, CYP6B27, CYP9A14, CYP6AE11, and CYP4M7). These findings are important for advancing our understanding of the biochemical and molecular response of insects to plant toxins and have implications for a smart pest control.

  19. Dermal quercetin smartCrystals®: Formulation development, antioxidant activity and cellular safety.

    PubMed

    Hatahet, T; Morille, M; Hommoss, A; Dorandeu, C; Müller, R H; Bégu, S

    2016-05-01

    Flavonoids are natural plant pigments, which possess high antioxidative and antiradical activities. However, their poor water solubility led to a limited bioavailability. To overcome this major hurdle, quercetin nanocrystals were produced implementing smartCrystals® technology. This process combines bead milling and subsequent high-pressure homogenization at relatively low pressure (300bar). To test the possibility to develop a dermal formulation from quercetin smartCrystals®, quercetin nanosuspensions were admixed to Lutrol® F127 and hydroxythylcellulose nonionic gels. The physicochemical properties (morphology, size and charge), saturation solubility, dissolution velocity and the antioxidant properties (DPPH assay) as well as the cellular interaction of the produced quercetin smartCrystals® were studied and compared to crude quercetin powder. Quercetin smartCrystals® showed a strong increase in the saturation solubility and the dissolution velocity (7.6 fold). SmartCrystals® loaded or not into gels proved to be physically stable over a period of three months at 25°C. Interestingly, in vitro DPPH assay confirmed the preservation of quercetin antioxidative properties after nanonization. In parallel, the nanocrystalline form did not display cellular toxicity, even at high concentration (50μg/ml), as assayed on an epithelial cell line (VERO cells). In addition, the nanocrystalline form confirmed a protective activity for VERO cells against hydrogen peroxide induced toxicity in vitro. This new formulation presents a promising approach to deliver quercetin efficiently to skin in well-tolerated formulations.

  20. Behavior of the potential antitumor V(IV)O complexes formed by flavonoid ligands. 2. Characterization of sulfonate derivatives of quercetin and morin, interaction with the bioligands of the plasma and preliminary biotransformation studies.

    PubMed

    Sanna, Daniele; Ugone, Valeria; Pisano, Luisa; Serra, Maria; Micera, Giovanni; Garribba, Eugenio

    2015-12-01

    The biotransformation in the plasma and red blood cells of two potential antitumor V(IV)O complexes formed by flavonoid ligands (quercetin or que and morin or mor) and their sulfonic derivatives (quercetin-5'-sulfonic acid or que(S) and morin-5'-sulfonic acid or mor(S)) was studied by spectroscopic (EPR, Electron Paramagnetic Resonance) and computational (DFT, Density Functional Theory) methods. Que and que(S) form with V(IV)O stable complexes, and in the systems with apo-transferrin (apo-hTf) and albumin (HSA) VO(que)2 and VO(que(S))2 remain unchanged. VO(mor)2 and VO(mor(S))2 undergo displacement reactions to give the partial formation of (VO)x(HSA) and (VO)(apo-hTf)/(VO)2(apo-hTf); moreover, mor(S) forms with apo-transferrin and albumin mixed species VO-mor(S)-apo-hTf and VO-mor(S)-HSA. In the systems with apo-hTf and HSA anisotropic EPR spectra at room temperature are detected in which the protein is not directly coordinated to V(IV)O(2+) ion. This is explained assuming that the bis-chelated complexes interact strongly with the proteins through a network of hydrogen bonds with the polar groups present on the protein surface. It is suggested that this "indirect" transport of V(IV)O species could be common to all the species containing ligands which can interact with the blood proteins. Uptake experiments by red blood cells were also carried out, using vanadium concentration of 5.0×10(-4)M and incubation time in the range 0-160min. VO(que)2/VO(que(S))2 and VO(mor)2/VO(mor(S))2 cross the erythrocytes membrane and in the cytosol VO(que)2/VO(que(S))2 do not transform, whereas VO(mor)2/VO(mor(S))2 give the partial formation of mixed species with hemoglobin (Hb) and other V(IV)O complexes. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Quercetin, a natural product supplement, impairs mitochondrial bioenergetics and locomotor behavior in larval zebrafish (Danio rerio).

    PubMed

    Zhang, Ji-Liang; Laurence Souders, Christopher; Denslow, Nancy D; Martyniuk, Christopher J

    2017-07-15

    Quercetin is a natural product that is sold as a supplement in health food stores. While there are reported benefits for this flavonoid as a dietary supplement due to antioxidant properties, the full scope of its biological interactions has not been fully addressed. To learn more about the mechanisms of action related to quercetin, we exposed zebrafish (Danio rerio) embryos to 1 and 10μg/L quercetin for 96h starting at 3h post fertilization. Quercetin up to 10μg/L did not induce significant mortality in developing fish, but did increase prevalence of an upward-curved dorsal plane in hatched larvae. To determine whether this developmental defect was potentially related to mitochondrial bioenergetics during development, we measured oxygen consumption rate in whole embryos following a 24-hour exposure to quercetin. Basal mitochondrial and ATP-linked respiration were decreased at 1 and 10μg/L quercetin, and maximal respiration was decreased at 10μg/L quercetin, suggesting that quercetin impairs mitochondrial bioenergetics. This is proposed to be related to the deformities observed during development. Due to the fact that ATP production was affected by quercetin, larval behaviors related to locomotion were investigated, as well as transcriptional responses of six myogenesis transcripts. Quercetin at 10μg/L significantly reduced the swimming velocity of zebrafish larvae. The expression levels of both myostatin A (mstna) and myogenic differentiation (myoD) were also altered by quercetin. Mstna, an inhibitory factor for myogenesis, was significantly increased at 1μg/L quercetin exposure, while myoD, a stimulatory factor for myogenesis, was significantly increased at 10μg/L quercetin exposure. There were no changes in transcripts related to apoptosis (bcl2, bax, casp3, casp7), but we did observe a decrease in mRNA levels for catalase (cat) in fish exposed to each dose, supporting an oxidative stress response. Our data support the hypothesis that quercetin may affect

  2. Glucuronidation does not suppress the estrogenic activity of quercetin in yeast and human breast cancer cell model systems.

    PubMed

    Ruotolo, Roberta; Calani, Luca; Brighenti, Furio; Crozier, Alan; Ottonello, Simone; Del Rio, Daniele

    2014-10-01

    Several plant-derived molecules, referred to as phytoestrogens, are thought to mimic the actions of endogenous estrogens. Among these, quercetin, one of the most widespread flavonoids in the plant kingdom, has been reported as estrogenic in some occasions. However, quercetin occurs in substantial amounts as glycosides such as quercetin-3-O-glucoside (isoquercitrin) and quercetin-3-O-rutinoside (rutin) in dietary sources. It is now well established that quercetin undergoes substantial phase II metabolism after ingestion by humans, with plasma metabolites after a normal dietary intake rarely exceeding nmol/L concentrations. Therefore, attributing phytoestrogenic activity to flavonoids without taking into account the fact that it is their phase II metabolites that enter the circulatory system, will almost certainly lead to misleading conclusions. With the aim of clarifying the above issue, the goal of the present study was to determine if plant-associated quercetin glycosides and human phase II quercetin metabolites, actually found in human biological fluids after intake of quercetin containing foods, are capable of interacting with the estrogen receptors (ER). To this end, we used a yeast-based two-hybrid system and an estrogen response element-luciferase reporter assay in an ER-positive human cell line (MCF-7) to probe the ER interaction capacities of quercetin and its derivatives. Our results show that quercetin-3-O-glucuronide, one of the main human phase II metabolites produced after intake of dietary quercetin, displays ERα- and ERβ-dependent estrogenic activity, the functional consequences of which might be related to the protective activity of diets rich in quercetin glycosides.

  3. Preparation of efficient quercetin delivery system on Zn-modified mesoporous SBA-15 silica carrier.

    PubMed

    Trendafilova, Ivalina; Szegedi, Agnes; Mihály, Judith; Momekov, Georgi; Lihareva, Nadejda; Popova, Margarita

    2017-04-01

    Mesoporous silica material type SBA-15 was modified with different amounts of Zn (2 and 4wt.%) by incipient wetness impregnation method in ethanol. The parent, Zn-modified and quercetin loaded samples, were characterized by XRD, N2 physisorption, TEM, thermal gravimetric analysis, UV-vis and FT-IR spectroscopies and in vitro release of quercetin at pH5.5 which is typical of dermal formulations. By this loading method anhydrous quercetin was formed on the silica carrier It was found that the different hydrate forms of quercetin (dihydrate, monohydrate, anhydrite) significantly influence the physico-chemical properties of the delivery system. It was found that hydrate forms of quercetin can be differentiated by XRD and by FT-IR spectroscopic methods. Thus, by evaluating the interaction of the drug with the silica carrier the changes due to its hydration state always have to be taken into account. Formation of Zn-quercetin complex was evidenced on zinc modified SBA-15 silica by FT-IR spectroscopy. High quercetin loading capacity (over 40wt.%) could be achieved on the parent and Zn-containing SBA-15 samples. The in-vitro release process at pH=5.5 showed slower quercetin release from Zn-modified SBA-15 samples compared to the parent one. Additionally, the comparative cytotoxic experiments evidenced that quercetin encapsulated in Zn-modified silica carriers has superior antineoplastic potential against HUT-29 cells compared to free drug. Zn-modified SBA-15 silica particles could be promising carriers for dermal delivery of quercetin. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Cytotoxicity comparison of quercetin and its metabolites from in vitro fermentation of several gut bacteria.

    PubMed

    Zhang, Zhichao; Peng, Xichun; Zhang, Ning; Liu, Liu; Wang, Yong; Ou, Shiyi

    2014-09-01

    Part of quercetin is coerced into the colon after ingestion and interacts with the gut microbiota. The interaction between quercetin and gut microbiota will influence human health. The cytotoxicity of quercetin and its metabolites from human gut bacteria in vitro fermentation was investigated in this study. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide) (MTT) and agar diffusion disc methods were individually applied in vitro to examine their inhibitory effect on three cultured human cancer cells and five pathogenic bacteria species. The results showed that the metabolites from Clostridium perfringens and Bacteroides fragilis exerted a strong inhibitory effect (P < 0.05) on HCT-116 cells and that of Weissella confusa was stronger (P < 0.01) on both A549 cells and HeLa cells than on the others. Most metabolites have similar or decreased inhibitory ability on human cancer cells compared to quercetin itself. This inhibitory effect had not been detected in quercetin and its metabolites in five common pathogenic bacteria species. Quercetin is a potential chemopreventive agent. However, this study reported that some gut bacteria can improve their function of inhibiting cancer cells after fermenting quercetin.

  5. Quercetin Blocks Airway Epithelial Cell Chemokine Expression

    PubMed Central

    Nanua, Suparna; Zick, Suzanna M.; Andrade, Juan E.; Sajjan, Umadevi S.; Burgess, John R.; Lukacs, Nicholas W.; Hershenson, Marc B.

    2006-01-01

    Quercetin (3,3′,4′,5,7-pentahydroxyflavone), a dietary flavonoid, is an inhibitor of phosphatidylinositol (PI) 3-kinase and potent antioxidant. We hypothesized that quercetin blocks airway epithelial cell chemokine expression via PI 3-kinase–dependent mechanisms. Pretreatment with quercetin and the PI 3–kinase inhibitor LY294002 each reduced TNF-α–induced IL-8 and monocyte chemoattractant protein (MCP)-1 (also called CCL2) expression in cultured human airway epithelial cells. Quercetin also inhibited TNF-α–induced PI 3-kinase activity, Akt phosphorylation, intracellular H2O2 production, NF-κB transactivation, IL-8 promoter activity, and steady-state mRNA levels, consistent with the notion that quercetin inhibits chemokine expression by attenuating NF-κB transactivation via a PI 3-kinase/Akt-dependent pathway. Quercetin also reduced TNF-α–induced chemokine secretion in the presence of the transcriptional inhibitor actinomycin D, while inducing phosphorylation of eukaryotic translation initiation factor (eIF)-2α, suggesting that quercetin attenuates chemokine expression by post-transcriptional as well as transcriptional mechanisms. Finally, we tested the effects of quercetin in cockroach antigen–sensitized and –challenged mice. These mice show MCP-1–dependent airways hyperresponsiveness and inflammation. Quercetin significantly reduced lung MCP-1 and methacholine responsiveness. We conclude that quercetin blocks airway cell chemokine expression via transcriptional and post-transcriptional pathways. PMID:16794257

  6. The Influence of Single-Dose and Short-Term Administration of Quercetin on the Pharmacokinetics of Midazolam in Humans.

    PubMed

    Nguyen, Mai Anh; Staubach, Petra; Wolffram, Siegfried; Langguth, Peter

    2015-09-01

    Quercetin is a plant flavonol that is available from both daily diet and nutraceuticals. To investigate the effect of acute and short-term intake of high-dose quercetin on CYP3A-mediated metabolism, 10 healthy volunteers received 7.5 mg oral midazolam without, with a single dose of 1500 mg quercetin and after 1-week supplementation with 1500 mg quercetin daily. A substudy was performed in three subjects to explore the impact of repeated quercetin intake on intravenously administered midazolam. Coadministration with a single dose of quercetin did not significantly alter the pharmacokinetics of midazolam and its 1'-hydroxymetabolite, but following short-term quercetin intake, there was a trend to reduced midazolam exposure (geometric mean ratio of test-control area under the plasma concentration-time curve (AUC0-∞ ): 0.82; 90% confidence interval: 0.61-1.10) and midazolam-metabolite AUC0-∞ ratios were decreased by 9.7%-47.6% from control in seven subjects. The tendency was opposite when midazolam was given intravenously. We conclude that a single dose of quercetin would not provoke any toxic adverse events when coadministered with midazolam, whereas repeated quercetin intake can reduce systemic exposure to the orally given drug by increasing its CYP3A-catalyzed metabolism. As the effect deviated after intravenous drug administration, different mechanisms of interaction may be involved at the intestinal site compared with the liver. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  7. Effects of quercetin on human α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor-mediated ion currents.

    PubMed

    Shin, Tae-Joon; Choi, Sun-Hye; Lee, Byung-Hwan; Pyo, Mi Kyung; Hwang, Sung-Hee; Kim, Bo-Ra; Lee, Sang-Mok; Han, Ye Sun; Lee, Jun-Ho; Park, Ji-Ho; Kim, Hyoung-Chun; Rhim, Hyewhon; Nah, Seung-Yeol

    2010-01-01

    Quercetin is a low molecular weight flavonoid found in dietary fruits and vegetables. Quercetin, like other flavonoids, has demonstrated neuroprotective effects in vitro and in vivo. However, relatively little is known about how quercetin achieves its neuroprotective abilities. The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor is one of several excitatory receptors, which play an important role in postsynaptic neurotransmission. Over-stimulation of ionotropic glutamate receptor including AMPA receptors is closely associated with excitatory neurotoxicities. In the present study, we investigated the effects of quercetin on the glutamate-induced inward current (IGlu) in Xenopus oocytes that heterologously express human AMPA receptor and stargazin, an auxiliary subunit of AMPA receptor. IGlu was measured using the two-electrode voltage clamp technique. In oocytes injected with cRNAs coding AMPA receptor (GluR1) and stargazin, quercetin inhibited IGlu in a reversible and concentration-dependent manner. The IC50 was 84.9+/-15.0 microM. Quercetin action on IGlu was attenuated by increasing glutamate concentration, and was membrane holding potential-dependent. These results show a possibility that quercetin interacts with AMPA receptor, which was heterologously expressed in Xenopus oocytes and that quercetin action on IGlu of AMPA receptor could be one of contributions of quercetin-mediated neuroprotections.

  8. A method to determine quercetin by enhanced luminol electrogenerated chemiluminescence (ECL) and quercetin autoxidation.

    PubMed

    Lei, Rong; Xu, Xiao; Yu, Fei; Li, Na; Liu, Hu-Wei; Li, Kèan

    2008-05-30

    Quercetin greatly enhanced luminol electrochemiluminescence of quercetin in alkaline solution. When the concentration of luminol was 0.1 mol L(-1), the detection limit for quercetin was 2.0x10(-8) mol L(-1) with a linear range from 1.0x10(-7) to 2x10(-5) mol L(-1). The pH and buffer substantially affected ECL intensity. Quercetin was autoxidized in alkaline aqueous solution. The rate of autoxidation of quercetin in various pH buffers and borate concentrations were measured. Borate was found to inhibit quercetin autoxidation and compromise quercetin enhancement effect on luminol ECL to some extent. Two final autoxidation products were identified with LC-MS methods. Autoxidation process was associated with enhancement of ECL intensity. The ROS generated during quercetin autoxidation enhanced the ECL intensity.

  9. Involvement of P-glycoprotein in regulating cellular levels of Ginkgo flavonols: quercetin, kaempferol, and isorhamnetin.

    PubMed

    Wang, Yi; Cao, Jiang; Zeng, Su

    2005-06-01

    Quercetin, kaempferol, and isorhamnetin were the most important flavonoid constituents in extracts from Ginkgo biloba leaves. Transport studies of Ginkgo flavonols were performed in Caco-2 cell mono-layers. Their apparent permeability in absorptive and secretion directions was determined, and quercetin, kaempferol and isorhamnetin displayed polarized transport, with the Papp,B-A being higher than the Papp,A-B (P<0.01 for quercetin, P<0.001 for kaempferol and isorhamnetin, Student's t-test). Bcap37/MDR1 cells, which were transfected with a P-glycoprotein (P-gp) gene construct, were treated with quercetin, kaempferol or isorhamnetin. The concentrations of Ginkgo flavonol in Bcap37/MDR1 cells were lower than those in parent cells (P<0.05 for quercetin, P<0.01 for isorhamnetin, Mann-Whitney U test). The concentrations of the flavonol in transfected cells increased when incubated with the P-gp inhibitor verapamil (P<0.05 for kaempferol, Mann-WhitneyU test). A colorometric assay for ATPase activity was applied to the detection of interaction of flavonol with P-gp. Quercetin and kaempferol inhibited the ATPase activity, and isorhamnetin stimulated the ATPase activity (P<0.05 for isorhamnetin, Mann Whitney U test). The results indicated that Ginkgo flavonols quercetin, kaempferol and isorhamnetin were substrates of P-gp. The P-gp type efflux pump might limit the bioavailability of Ginkgo flavonols.

  10. Improvement of quercetin protective effect against oxidative stress skin damages by incorporation in nanovesicles.

    PubMed

    Manca, Maria Letizia; Castangia, Ines; Caddeo, Carla; Pando, Daniel; Escribano, Elvira; Valenti, Donatella; Lampis, Sandrina; Zaru, Marco; Fadda, Anna Maria; Manconi, Maria

    2014-11-01

    Quercetin was incorporated in glycerosomes, new phospholipid-glycerol vesicles, and their protective effect against oxidative stress skin damages was extensively evaluated. In particular, the concentration-dependent effect of glycerol (from 10 to 50%) on vesicle suitability as cutaneous carriers of quercetin was carefully assessed. All vesicles were unilamellar and small in size (∼80-110 nm), as confirmed by cryo-TEM observation, with a drug incorporation efficiency ranging between 81 and 91%. SAXS studies, performed to investigate the bilayer arrangement, indicated a strong, dose-dependent interaction of glycerol with the polar portions of the phospholipid molecules, while quercetin did not significantly change the bilayer packing. In vitro studies on newborn pig skin underlined the concentration-dependent ability of glycerosomes to promote quercetin accumulation in the different layers, also confirmed by confocal microscopic observation of skin treated with fluorescent vesicles. Quercetin incorporated into liposomal and glycerosomal nanoformulations showed a strong ability to scavenge free radicals (DPPH test) and protect human keratinocytes in vitro against hydrogen peroxide damage. Moreover, quercetin-loaded vesicles were avidly taken up by keratinocytes in vitro. Overall, results indicate 40 and 50% glycerosomes as promising nanosystems for the improvement of cutaneous quercetin delivery and keratinocyte protection against oxidative stress damage.

  11. Mood and Vigilance Following Quercetin Supplementation

    DTIC Science & Technology

    2007-11-02

    controlled study was undertaken to test whether quercetin aglycone affects mood and vigilance in humans. Block randomization was used to assign 57...2,000 mg quercetin or 2,000 mg placebo 1 hour prior to completing a 45-minute scanning visual vigilance task. Profile of Mood States (POMS... quercetin concentrations were measured in plasma samples collected 2-hours after treatment. The caffeine group significantly outperformed the placebo group

  12. Enriched cereal bars are more effective in increasing plasma quercetin compared with quercetin from powder-filled hard capsules.

    PubMed

    Egert, Sarah; Wolffram, Siegfried; Schulze, Beate; Langguth, Peter; Hubbermann, Eva Maria; Schwarz, Karin; Adolphi, Berit; Bosy-Westphal, Anja; Rimbach, Gerald; Müller, Manfred James

    2012-02-01

    The flavonol quercetin, is one of the major flavonoids found in edible plants. The bioavailability of quercetin in humans may be influenced by the food matrix in which it is consumed as well as by its chemical and physical form. The objective of the present study was to investigate the biokinetics of quercetin from quercetin-enriched cereal bars and quercetin powder-filled hard capsules. In a randomised, single-blinded, diet-controlled cross-over study, six healthy women aged 22-28 years took a single oral dose of approximately 130 mg quercetin equivalents from either quercetin-enriched cereal bars (containing 93·3 % quercetin aglycone plus 6·7 % quercetin-4'-glucoside) or quercetin powder-filled hard capsules (100 % quercetin aglycone). Blood samples were drawn before and after quercetin administration over a 24 h period. The concentrations of quercetin and its monomethylated derivatives, isorhamnetin (3'-O-methyl quercetin) and tamarixetin (4'-O-methyl quercetin), were measured by HPLC with fluorescence detection after plasma enzymatic treatment. The systemic availability as determined by comparing the plasma concentration-time curves of quercetin was found to be five times and the cmax values six times higher after ingestion of 130 mg quercetin by quercetin-enriched cereal bars than after ingestion by quercetin capsules. In contrast, tmax did not differ significantly between the two treatments. The cmax values for isorhamnetin and tamarixetin were four and nine times higher after ingestion of quercetin by quercetin-enriched cereal bars than after ingestion by quercetin capsules. In conclusion, quercetin from quercetin-enriched cereal bars is significantly more bioavailable than from quercetin powder-filled hard capsules.

  13. Role of Bax in quercetin-induced apoptosis in human prostate cancer cells

    PubMed Central

    Lee, Dae-Hee; Szczepanski, Miroslaw; Lee, Yong J.

    2012-01-01

    The aim of this study was to investigate the effect of quercetin, a flavonoid, on the apoptotic pathway in a human prostate cell line (LNCaP). We observed that treatment of cells for 24 h with quercetin induced cell death in a dose-dependent manner. A sustained inhibition of the major survival signal, Akt, occurred in quercetin-treated cells. Treatment of LNCaP cells with an apoptosis inducing concentration of quercetin (100 μM) resulted in a rapid decrease in the inhibitory Ser(473) phosphorylation of Akt leading to inhibition of its kinase activity. Quercetin treatment (100 μM) also caused a decrease in Ser(136) phosphorylation of Bad, which is a downstream target of Akt. Protein interaction assay revealed that during treatment with quercetin, Bcl-xL dissociated from Bax and then associated with Bad. Our results also show that quercetin decreases the Bcl-xL:Bax ratio and increases translocation and multimerization of Bax to the mitochondrial membrane. The translocation is accompanied by cytochrome c release, and procaspases-3, -8 and -9 cleavage and increased poly (ADP-ribose) polymerase (PARP) cleavage. Similar results were observed in human colon cancer HCT116Bax+/+ cell line, but not HCT116Bax−/− cell line. Interestingly, at similar concentrations (100 μM), quercetin treatment did not affect the viability or rate of apoptosis in normal human prostate epithelial cell line (PrEC) and rat prostate epithelial cell line (YPEN-1). Our results indicate that the apoptotic processes caused by quercetin are mediated by the dissociation of Bax from Bcl-xL and the activation of caspase families in human prostate cancer cells. PMID:18455702

  14. Quercetin Inhibits Intestinal Iron Absorption and Ferroportin Transporter Expression In Vivo and In Vitro

    PubMed Central

    Balesaria, Sara; Skinner, Vernon; Debnam, Edward S.; Srai, Surjit K. S.; Sharp, Paul A.

    2014-01-01

    Balancing systemic iron levels within narrow limits is critical for maintaining human health. There are no known pathways to eliminate excess iron from the body and therefore iron homeostasis is maintained by modifying dietary absorption so that it matches daily obligatory losses. Several dietary factors can modify iron absorption. Polyphenols are plentiful in human diet and many compounds, including quercetin – the most abundant dietary polyphenol – are potent iron chelators. The aim of this study was to investigate the acute and longer-term effects of quercetin on intestinal iron metabolism. Acute exposure of rat duodenal mucosa to quercetin increased apical iron uptake but decreased subsequent basolateral iron efflux into the circulation. Quercetin binds iron between its 3-hydroxyl and 4-carbonyl groups and methylation of the 3-hydroxyl group negated both the increase in apical uptake and the inhibition of basolateral iron release, suggesting that the acute effects of quercetin on iron transport were due to iron chelation. In longer-term studies, rats were administered quercetin by a single gavage and iron transporter expression measured 18 h later. Duodenal FPN expression was decreased in quercetin-treated rats. This effect was recapitulated in Caco-2 cells exposed to quercetin for 18 h. Reporter assays in Caco-2 cells indicated that repression of FPN by quercetin was not a transcriptional event but might be mediated by miRNA interaction with the FPN 3′UTR. Our study highlights a novel mechanism for the regulation of iron bioavailability by dietary polyphenols. Potentially, diets rich in polyphenols might be beneficial for patients groups at risk of iron loading by limiting the rate of intestinal iron absorption. PMID:25058155

  15. Perorally active nanomicellar formulation of quercetin in the treatment of lung cancer

    PubMed Central

    Tan, Bee-Jen; Liu, Yuanjie; Chang, Kai-Lun; Lim, Bennie KW; Chiu, Gigi NC

    2012-01-01

    Background Realizing the therapeutic benefits of quercetin is mostly hampered by its low water solubility and poor absorption. In light of the advantages of nanovehicles in the delivery of flavanoids, we aimed to deliver quercetin perorally with nanomicelles made from the diblock copolymer, polyethylene glycol (PEG)-derivatized phosphatidylethanolamine (PE). Methods Quercetin-loaded nanomicelles were prepared by using the film casting method, and were evaluated in terms of drug incorporation efficiency, micelle size, interaction with Caco-2 cells, and anticancer activity in the A549 lung cancer cell line and murine xenograft model. Results The incorporation efficiency into the nanomicelles was ≥88.9% when the content of quercetin was up to 4% w/w, with sizes of 15.4–18.5 nm and polydispersity indices of <0.250. Solubilization of quercetin by the nanomicelles increased its aqueous concentration by 110-fold. The quercetin nanomicelles were stable when tested in simulated gastric (pH 1.2) and intestinal (pH 7.4) fluids, and were non-toxic to the Caco-2 cells as reflected by reversible reduction in transepithelial electrical resistance and ≤25% lactose dehydrogenase release. The anticancer activity of quercetin could be significantly improved over the free drug through the nanomicellar formulation when tested using the A549 cancer cell line and murine xenograft model. The nanomicellar quercetin formulation was well tolerated by the tumor-bearing animals, with no significant weight loss observed at the end of the 10-week study period. Conclusion A stable PEG-PE nanomicellar formulation of quercetin was developed with enhanced peroral anticancer activity and no apparent toxicity to the intestinal epithelium. PMID:22334787

  16. Quercetin inhibits intestinal iron absorption and ferroportin transporter expression in vivo and in vitro.

    PubMed

    Lesjak, Marija; Hoque, Rukshana; Balesaria, Sara; Skinner, Vernon; Debnam, Edward S; Srai, Surjit K S; Sharp, Paul A

    2014-01-01

    Balancing systemic iron levels within narrow limits is critical for maintaining human health. There are no known pathways to eliminate excess iron from the body and therefore iron homeostasis is maintained by modifying dietary absorption so that it matches daily obligatory losses. Several dietary factors can modify iron absorption. Polyphenols are plentiful in human diet and many compounds, including quercetin--the most abundant dietary polyphenol--are potent iron chelators. The aim of this study was to investigate the acute and longer-term effects of quercetin on intestinal iron metabolism. Acute exposure of rat duodenal mucosa to quercetin increased apical iron uptake but decreased subsequent basolateral iron efflux into the circulation. Quercetin binds iron between its 3-hydroxyl and 4-carbonyl groups and methylation of the 3-hydroxyl group negated both the increase in apical uptake and the inhibition of basolateral iron release, suggesting that the acute effects of quercetin on iron transport were due to iron chelation. In longer-term studies, rats were administered quercetin by a single gavage and iron transporter expression measured 18 h later. Duodenal FPN expression was decreased in quercetin-treated rats. This effect was recapitulated in Caco-2 cells exposed to quercetin for 18 h. Reporter assays in Caco-2 cells indicated that repression of FPN by quercetin was not a transcriptional event but might be mediated by miRNA interaction with the FPN 3'UTR. Our study highlights a novel mechanism for the regulation of iron bioavailability by dietary polyphenols. Potentially, diets rich in polyphenols might be beneficial for patients groups at risk of iron loading by limiting the rate of intestinal iron absorption.

  17. Effect of different exposed lights on quercetin and quercetin glucoside content in onion (Allium cepa L.).

    PubMed

    Ko, Eun Young; Nile, Shivraj Hariram; Sharma, Kavita; Li, Guan Hao; Park, Se Won

    2015-07-01

    Quercetin and quercetin glucosides are the major flavonols present in onion (Allium cepa L.) and are predominantly present as quercetin, quercetin-3,4'-diglucoside and quercetin-4'-glucoside. Effect of different light wavelengths on onion after harvest and storage, with fluorescent, blue, red and ultra violet light influenced the quercetin and quercetin glucosides profile. In a peeled onion, all the light treatments elevated quercetin content in bulb. Among them, particularly fluorescent light effect was more eminent which stimulates the maximum synthesis of quercetin in onion. In case of whole onion bulb, skin and pulp showed different responses to light treatment, respectively. The pulp had the highest quercetin glucosides under blue light, whereas the lowest under fluorescent light. Onion skin showed nearly opposite pattern as compared to the pulp. In particular, light treatment proved to be a better way to increase the level of quercetin content in onions which might be utilized for industrial production of bioactive compounds from onion and onion waste products.

  18. Effect of different exposed lights on quercetin and quercetin glucoside content in onion (Allium cepa L.)

    PubMed Central

    Ko, Eun Young; Nile, Shivraj Hariram; Sharma, Kavita; Li, Guan Hao; Park, Se Won

    2014-01-01

    Quercetin and quercetin glucosides are the major flavonols present in onion (Allium cepa L.) and are predominantly present as quercetin, quercetin-3,4′-diglucoside and quercetin-4′-glucoside. Effect of different light wavelengths on onion after harvest and storage, with fluorescent, blue, red and ultra violet light influenced the quercetin and quercetin glucosides profile. In a peeled onion, all the light treatments elevated quercetin content in bulb. Among them, particularly fluorescent light effect was more eminent which stimulates the maximum synthesis of quercetin in onion. In case of whole onion bulb, skin and pulp showed different responses to light treatment, respectively. The pulp had the highest quercetin glucosides under blue light, whereas the lowest under fluorescent light. Onion skin showed nearly opposite pattern as compared to the pulp. In particular, light treatment proved to be a better way to increase the level of quercetin content in onions which might be utilized for industrial production of bioactive compounds from onion and onion waste products. PMID:26150744

  19. The effect of quercetin on genetic expression of the commensal gut microbes Bifidobacterium catenulatum, Enterococcus caccae and Ruminococcus gauvreauii.

    PubMed

    Firrman, Jenni; Liu, LinShu; Zhang, Liqing; Arango Argoty, Gustavo; Wang, Minqian; Tomasula, Peggy; Kobori, Masuko; Pontious, Sherri; Xiao, Weidong

    2016-12-01

    Quercetin is one of the most abundant polyphenols found in fruits and vegetables. The ability of the gut microbiota to metabolize quercetin has been previously documented; however, the effect that quercetin may have on commensal gut microbes remains unclear. In the present study, the effects of quercetin on the commensal gut microbes Ruminococcus gauvreauii, Bifidobacterium catenulatum and Enterococcus caccae were determined through evaluation of growth patterns and cell morphology, and analysis of genetic expression profiles between quercetin treated and non-treated groups using Single Molecule RNA sequencing via Helicos technology. Results of this study revealed that phenotypically, quercetin did not prevent growth of Ruminococcus gauvreauii, mildly suppressed growth of Bifidobacterium catenulatum, and moderately inhibited growth of Enterococcus caccae. Genetic analysis revealed that in response to quercetin, Ruminococcus gauvreauii down regulated genes responsible for protein folding, purine synthesis and metabolism. Bifidobacterium catenulatum increased expression of the ABC transport pathway and decreased metabolic pathways and cell wall synthesis. Enterococcus caccae upregulated genes responsible for energy production and metabolism, and downregulated pathways of stress response, translation and sugar transport. For the first time, the effect of quercetin on the growth and genetic expression of three different commensal gut bacteria was documented. The data provides insight into the interactions between genetic regulation and growth. This is also a unique demonstration of how RNA single molecule sequencing can be used to study the gut microbiota.

  20. Differential Effects of Quercetin and Quercetin Glycosides on Human α7 Nicotinic Acetylcholine Receptor-Mediated Ion Currents

    PubMed Central

    Lee, Byung-Hwan; Choi, Sun-Hye; Kim, Hyeon-Joong; Jung, Seok-Won; Hwang, Sung-Hee; Pyo, Mi-Kyung; Rhim, Hyewhon; Kim, Hyoung-Chun; Kim, Ho-Kyoung; Lee, Sang-Mok; Nah, Seung-Yeol

    2016-01-01

    Quercetin is a flavonoid usually found in fruits and vegetables. Aside from its antioxidative effects, quercetin, like other flavonoids, has a various neuropharmacological actions. Quercetin-3-O-rhamnoside (Rham1), quercetin-3-O-rutinoside (Rutin), and quercetin-3-(2(G)-rhamnosylrutinoside (Rham2) are mono-, di-, and tri-glycosylated forms of quercetin, respectively. In a previous study, we showed that quercetin can enhance α7 nicotinic acetylcholine receptor (α7 nAChR)-mediated ion currents. However, the role of the carbohydrates attached to quercetin in the regulation of α7 nAChR channel activity has not been determined. In the present study, we investigated the effects of quercetin glycosides on the acetylcholine induced peak inward current (IACh) in Xenopus oocytes expressing the α7 nAChR. IACh was measured with a two-electrode voltage clamp technique. In oocytes injected with α7 nAChR copy RNA, quercetin enhanced IACh, whereas quercetin glycosides inhibited IACh. Quercetin glycosides mediated an inhibition of IACh, which increased when they were pre-applied and the inhibitory effects were concentration dependent. The order of IACh inhibition by quercetin glycosides was Rutin≥Rham1>Rham2. Quercetin glycosides-mediated IACh enhancement was not affected by ACh concentration and appeared voltage-independent. Furthermore, quercetin-mediated IACh inhibition can be attenuated when quercetin is co-applied with Rham1 and Rutin, indicating that quercetin glycosides could interfere with quercetin-mediated α7 nAChR regulation and that the number of carbohydrates in the quercetin glycoside plays a key role in the interruption of quercetin action. These results show that quercetin and quercetin glycosides regulate the α7 nAChR in a differential manner. PMID:27098860

  1. Quercetin as a tyrosinase inhibitor: Inhibitory activity, conformational change and mechanism.

    PubMed

    Fan, Meihui; Zhang, Guowen; Hu, Xing; Xu, Ximing; Gong, Deming

    2017-10-01

    Quercetin, a flavonoid compound, was found to inhibit both monophenolase and diphenolase activities of tyrosinase, and its inhibition against diphenolase activity was in a reversible and competitive manner with an IC50 value of (3.08±0.74)×10(-5)molL(-1). Quercetin bound to tyrosinase driven by hydrophobic interaction, thereby resulted in a conformational change of tyrosinase and its intrinsic fluorescence quenching. Tyrosinase had one binding site for quercetin with the binding constant in the order of magnitude of 10(4)Lmol(-1). The molecular docking revealed that quercetin bound to the active site of tyrosinase and chelated a copper with the 3', 4'-dihydroxy groups. It can be deduced that the chelation may prevent the entrance of substrate and then inhibit the catalytic activity of tyrosinase. These findings may be helpful to understand the inhibition mechanism of quercetin on tyrosinase and functional research of quercetin in the treatment of pigmentation disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Structural evidence of quercetin multi-target bioactivity: A reverse virtual screening strategy.

    PubMed

    Carvalho, Diego; Paulino, Margot; Polticelli, Fabio; Arredondo, Florencia; Williams, Robert J; Abin-Carriquiry, Juan A

    2017-08-30

    The ubiquitous flavonoid quercetin is broadly recognized for showing diverse biological and health-promoting effects, such as anti-cancer, anti-inflammatory and cytoprotective activities. The therapeutic potential of quercetin and similar compounds for preventing such diverse oxidative stress-related pathologies has been generally attributed to their direct antioxidant properties. Nevertheless, accumulated evidence indicates that quercetin is also able to interact with multiple cellular targets influencing the activity of diverse signaling pathways. Even though there are a number of well-established protein targets such as phosphatidylinositol 3 kinase and xanthine oxidase, there remains a lack of a comprehensive knowledge of the potential mechanisms of action of quercetin and its target space. In the present work we adopted a reverse screening strategy based on ligand similarity (SHAFTS) and target structure (idTarget, LIBRA) resulting in a set of predicted protein target candidates. Furthermore, using this method we corroborated a broad array of previously experimentally tested candidates among the predicted targets, supporting the suitability of this screening approach. Notably, all of the predicted target candidates belonged to two main protein families, protein kinases and poly [ADP-ribose] polymerases. They also included key proteins involved at different points within the same signaling pathways or within interconnected signaling pathways, supporting a pleiotropic, multilevel and potentially synergistic mechanism of action of quercetin. In this context we highlight the value of quercetin's broad target profile for its therapeutic potential in diseases like inflammation, neurodegeneration and cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Synthesis, characterization, antioxidative and antitumor activities of solid quercetin rare earth(III) complexes.

    PubMed

    Zhou, J; Wang, L F; Wang, J Y; Tang, N

    2001-01-01

    Eight rare earth metal(II) complexes with quercetin ML3 x 6H2O [L=quercetin (3-OH group deprotonated); M = La, Nd, Eu, Gd, Tb, Dy, Tm and Y] have been synthesized and characterized by elemental analysis, complexometric titration, thermal analysis, conductivity, IR, UV, 1HNMR and fluorescence spectra techniques as well as cyclic voltammetry. The quercetin:metal stoichiometry and the equilibrium stability constant for metal binding to quercetin have been determined. The antioxidative and antitumor activities of quercetin x 2H2O and the complexes were tested by both the MTT and SRB methods. The results show that the suppression ratio of the complexes against the tested tumour cells are superior to quercetin x 2H2O. The property of LaL3 x 6H2O reacting with calf thymus DNA was studied by fluorescence methods. The La-complex binding to DNA has been determined by fluorescence titration in 0.05 M Tris-HCl, 0.5 M NaCl buffer (pH 7.0). The results indicate that the interaction of the complex with DNA is very evident.

  4. Effect of quercetin supplementation on maximal oxygen uptake in men and women.

    PubMed

    Ganio, Matthew S; Armstrong, Lawrence E; Johnson, Evan C; Klau, Jennifer F; Ballard, Kevin D; Michniak-Kohn, Bozena; Kaushik, Diksha; Maresh, Carl M

    2010-01-01

    Quercetin is a naturally occurring flavonoid with anti-oxidant and anti-inflammatory properties. The effect of quercetin supplementation on maximal oxygen uptake (VO(2max)) is unknown. The purpose of this investigation was to test the effects of quercetin supplementation on VO(2max) in untrained, sedentary individuals. After baseline treadmill VO(2max) testing, 11 participants (5 males, 6 females) ingested either placebo or quercetin-supplemented (1000 mg x day(-1)) food bars in a randomized, double-blind, counterbalanced, crossover research design. The participants ingested food bars for six consecutive mornings (5 days). On the sixth morning, participants underwent repeat VO(2max) testing. After a 22 day wash-out, the participants repeated baseline VO(2max) testing, daily consumption of the opposite food bars, and post-supplementation VO(2max) testing. The condition x time interaction for VO(2max) was non-significant when expressed in absolute (litres x min(-1); P = 0.929) and relative (ml x kg(-1) x min(-1); P = 0.778) terms. These findings were similar when taking sex into account (P > 0.05). The mean difference in VO(2max) change from pre to post between groups (quercetin vs. placebo) was 0.139 ml x kg(-1) x min(-1) (P = 0.780). Other physiological measures also were similar between conditions (P > 0.05). In conclusion, 5 days of quercetin supplementation did not influence VO(2max) or related variables in sedentary men and women.

  5. Generation of quercetin/cellulose acetate phthalate systems for delivery by supercritical antisolvent process.

    PubMed

    García-Casas, I; Montes, A; Pereyra, C; Martínez de la Ossa, E J

    2017-03-30

    Supercritical antisolvent process (SAS) has been used to precipitate microparticles of quercetin, a plant pigment found in many foods and used for medical treatments, pharmaceutical and cosmetic industries, together with nanoparticles of cellulose acetate phthalate (CAP), a polymer quite frequently used in drug delivery. Previously, precipitation of nanoparticles of CAP by the same process was studied at different conditions of pressure, temperature, CO2 and solution flow rates, nozzle diameter and initial concentration of the solution. Morphologies of the precipitates were analyzed by scanning electron microscopy (SEM). A range between 84 and 145nm of diameter in spherical particle were achievement in CAP precipitation. A same range of semi-spherical particles of CAP around 145nm and needle-like particle of quercetin was obtained in the coprecipitation experiments. X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were carried out to find out the possible loss of crystallinity of the coprecipitates and the possible interactions between the polymer and quercetin, respectively. Release profiles of quercetin were carried out in simulated gastric and intestinal fluids. Higher quercetin:polymer ratios in the coprecipitates are recommended to achieve faster release and higher solubilities of quercetin in the assayed time. This fact would allow its use in pharmaceutical, cosmetic or nutraceutical applications.

  6. RETRACTED: Quercetin suppresses insulin receptor signaling through inhibition of the insulin ligand-receptor binding and therefore impairs cancer cell proliferation.

    PubMed

    Wang, Feng; Yang, Yong

    2014-10-03

    Although the flavonoid quercetin is known to inhibit activation of insulin receptor signaling, the inhibitory mechanism is largely unknown. In this study, we demonstrate that quercetin suppresses insulin induced dimerization of the insulin receptor (IR) through interfering with ligand-receptor interactions, which reduces the phosphorylation of IR and Akt. This inhibitory effect further inhibits insulin stimulated glucose uptake due to decreased cell membrane translocation of glucose transporter 4 (GLUT4), resulting in impaired cancer cell proliferation. The effect of quercetin in inhibiting tumor growth was also evident in an in vivo model, indicating a potential future application for quercetin in the treatment of cancers. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. The leishmanicidal flavonols quercetin and quercitrin target Leishmania (Leishmania) amazonensis arginase.

    PubMed

    da Silva, Edson Roberto; Maquiaveli, Claudia do Carmo; Magalhães, Prislaine Pupolin

    2012-03-01

    Polyamine biosynthesis enzymes are promising drug targets for the treatment of leishmaniasis, Chagas' disease and African sleeping sickness. Arginase, which is a metallohydrolase, is the first enzyme involved in polyamine biosynthesis and converts arginine into ornithine and urea. Ornithine is used in the polyamine pathway that is essential for cell proliferation and ROS detoxification by trypanothione. The flavonols quercetin and quercitrin have been described as antitrypanosomal and antileishmanial compounds, and their ability to inhibit arginase was tested in this work. We characterized the inhibition of recombinant arginase from Leishmania (Leishmania) amazonensis by quercetin, quercitrin and isoquercitrin. The IC(50) values for quercetin, quercitrin and isoquercitrin were estimated to be 3.8, 10 and 4.3 μM, respectively. Quercetin is a mixed inhibitor, whereas quercitrin and isoquercitrin are uncompetitive inhibitors of L. (L.) amazonensis arginase. Quercetin interacts with the substrate l-arginine and the cofactor Mn(2+) at pH 9.6, whereas quercitrin and isoquercitrin do not interact with the enzyme's cofactor or substrate. Docking analysis of these flavonols suggests that the cathecol group of the three compounds interact with Asp129, which is involved in metal bridge formation for the cofactors Mn(A)(2+) and Mn(B)(2+) in the active site of arginase. These results help to elucidate the mechanism of action of leishmanicidal flavonols and offer new perspectives for drug design against Leishmania infection based on interactions between arginase and flavones. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Quercetin inhibits radiation-induced skin fibrosis.

    PubMed

    Horton, Jason A; Li, Fei; Chung, Eun Joo; Hudak, Kathryn; White, Ayla; Krausz, Kristopher; Gonzalez, Frank; Citrin, Deborah

    2013-08-01

    Radiation induced fibrosis of the skin is a late toxicity that may result in loss of function due to reduced range of motion and pain. The current study sought to determine if oral delivery of quercetin mitigates radiation-induced cutaneous injury. Female C3H/HeN mice were fed control chow or quercetin-formulated chow (1% by weight). The right hind leg was exposed to 35 Gy of X rays and the mice were followed serially to assess acute toxicity and hind leg extension. Tissue samples were collected for assessment of soluble collagen and tissue cytokines. Human and murine fibroblasts were subjected to clonogenic assays to determine the effects of quercetin on radiation response. Contractility of fibroblasts was assessed with a collagen contraction assay in the presence or absence of quercetin and transforming growth factor-β (TGF-β). Western blotting of proteins involved in fibroblast contractility and TGF-β signaling were performed. Quercetin treatment significantly reduced hind limb contracture, collagen accumulation and expression of TGF-β in irradiated skin. Quercetin had no effect on the radioresponse of fibroblasts or murine tumors, but was capable of reducing the contractility of fibroblasts in response to TGF-β, an effect that correlated with partial stabilization of phosphorylated cofilin. Quercetin is capable of mitigating radiation induced skin fibrosis and should be further explored as a therapy for radiation fibrosis.

  9. Quercetin Inhibits Radiation-Induced Skin Fibrosis

    PubMed Central

    Horton, Jason A.; Li, Fei; Chung, Eun Joo; Hudak, Kathryn; White, Ayla; Krausz, Kristopher; Gonzalez, Frank; Citrin, Deborah

    2013-01-01

    Radiation induced fibrosis of the skin is a late toxicity that may result in loss of function due to reduced range of motion and pain. The current study sought to determine if oral delivery of quercetin mitigates radiation-induced cutaneous injury. Female C3H/HeN mice were fed control chow or quercetin-formulated chow (1% by weight). The right hind leg was exposed to 35 Gy of X rays and the mice were followed serially to assess acute toxicity and hind leg extension. Tissue samples were collected for assessment of soluble collagen and tissue cytokines. Human and murine fibroblasts were subjected to clonogenic assays to determine the effects of quercetin on radiation response. Contractility of fibroblasts was assessed with a collagen contraction assay in the presence or absence of quercetin and transforming growth factor-β (TGF-β). Western blotting of proteins involved in fibroblast contractility and TGF-β signaling were performed. Quercetin treatment significantly reduced hind limb contracture, collagen accumulation and expression of TGF-β in irradiated skin. Quercetin had no effect on the radioresponse of fibroblasts or murine tumors, but was capable of reducing the contractility of fibroblasts in response to TGF-β, an effect that correlated with partial stabilization of phosphorylated cofilin. Quercetin is capable of mitigating radiation induced skin fibrosis and should be further explored as a therapy for radiation fibrosis. PMID:23819596

  10. Quercetin-induced cardioprotection against doxorubicin cytotoxicity

    PubMed Central

    2013-01-01

    Background Cancer has continually been the leading cause of death worldwide for decades. Thus, scientists have actively devoted themselves to studying cancer therapeutics. Doxorubicin is an efficient drug used in cancer therapy, but also produces reactive oxygen species (ROS) that induce severe cytotoxicity against heart cells. Quercetin, a plant-derived flavonoid, has been proven to contain potent antioxidant and anti-inflammatory properties. Thus, this in vitro study investigated whether quercetin can decrease doxorubicin-induced cytotoxicity and promote cell repair systems in cardiomyocyte H9C2 cells. Results Proteomic analysis and a cell biology assay were performed to investigate the quercetin-induced responses. Our data demonstrated that quercetin treatment protects the cardiomyocytes in a doxorubicin-induced heart damage model. Quercetin significantly facilitated cell survival by inhibiting cell apoptosis and maintaining cell morphology by rearranging the cytoskeleton. Additionally, 2D-DIGE combined with MALDI-TOF MS analysis indicated that quercetin might stimulate cardiomyocytes to repair damage after treating doxorubicin by modulating metabolic activation, protein folding and cytoskeleton rearrangement. Conclusion Based on a review of the literature, this study is the first to report detailed protective mechanisms for the action of quercetin against doxorubicin-induced cardiomyocyte toxicity based on in-depth cell biology and proteomic analysis. PMID:24359494

  11. Quercetin in brain diseases: Potential and limits.

    PubMed

    Dajas, Federico; Abin-Carriquiry, Juan Andrés; Arredondo, Florencia; Blasina, Fernanda; Echeverry, Carolina; Martínez, Marcela; Rivera, Felicia; Vaamonde, Lucía

    2015-10-01

    Quercetin is a ubiquitous flavonoid present in beverages, food and plants that has been demonstrated to have a role in the prevention of neurodegenerative and cerebrovascular diseases. In neuronal culture, quercetin increases survival against oxidative insults. Antioxidation appears to be a necessary but not sufficient condition for its neuroprotective action and modulation of intracellular signaling and transcription factors, increasing the expression of antioxidant and pro survival proteins and modulating inflammation, appears as important for neuronal protection. Quercetin also regulates the activity of kinases, changing the phosphorylation state of target molecules, resulting in modulation of cellular function and gene expression. Concentrations of quercetin higher than 100 μM consistently show cytotoxic and apoptotic effects by its autoxidation and generation of toxic quinones. In vivo, results are controversial with some studies showing neuroprotection by quercetin and others not, requiring a drug delivery system or chronic treatments to show neuroprotective effects. The blood and brain bioavailability of free quercetin after ingestion is a complex and controversial process that produces final low concentrations, a fact that has led to suggestions that metabolites would be active by themselves and/or as pro-drugs that would release the active aglycone in the brain. Available studies show that in normal or low oxidative conditions, chronic treatments with quercetin contributes to re-establish the redox regulation of proteins, transcription factors and survival signaling cascades that promote survival. In the presence of highly oxidative conditions such as in an ischemic tissue, quercetin could become pro-oxidant and toxic. At present, evidence points to quercetin as a preventive molecule for neuropathology when administered in natural matrices such as vegetables and food. More research is needed to support its use as a lead compound in its free form in

  12. Quercetin-induced apoptosis prevents EBV infection

    PubMed Central

    Lee, Minjung; Son, Myoungki; Ryu, Eunhyun; Shin, Yu Su; Kim, Jong Gwang; Kang, Byung Woog; Sung, Gi-Ho; Cho, Hyosun; Kang, Hyojeung

    2015-01-01

    Epstein-Barr virus (EBV) is a human gamma-1 herpesvirus that establishes a lifelong latency in over 90% of the world's population. During latency, virus exists predominantly as a chromatin-associated, multicopy episome in the nuclei of a variety of tumor cells derived from B cells, T cells, natural killer (NK) cells, and epithelial cells. Licorice is the root of Glycyrrhiza uralensis or G. glabra that has traditionally cultivated in eastern part of Asia. Licorice was reported to have anti-viral, anti-inflammatory, anti-atopic, hepatoprotective, anti-neurodegenerative, anti-tumor, anti-diabetic effects and so forth. Quercetin and isoliquiritigenin are produced from licorice and highly similar in molecular structure. They have diverse bioactive effects such as antiviral activity, anti-asthmatic activity, anti-cancer activity, anti-inflammation activity, monoamine-oxidase inhibitor, and etc. To determine anti-EBV and anti-EBVaGC (Epstein-Barr virus associated gastric carcinoma) effects of licorice, we investigated antitumor and antiviral effects of quercetin and isoliquiritigenin against EBVaGC. Although both quercetin and isoliquiritigenin are cytotoxic to SNU719 cells, quercetin induced more apoptosis in SNU719 cells than isoliquiritigenin, more completely eliminated DNMT1 and DNMT3A expressions than isoliquiritigenin, and more strongly affects the cell cycle progression of SNU719 than isoliquiritigenin. Both quercetin and isoliquiritigenin induce signal transductions to stimulate apoptosis, and induce EBV gene transcription. Quercetin enhances frequency of F promoter use, whereas isoliquiritigenin enhances frequency of Q promoter use. Quercetin reduces EBV latency, whereas isoliquiritigenin increases the latency. Quercetin increases more the EBV progeny production, and inhibits more EBV infection than isoliquiritigenin. These results indicate that quercetin could be a promising candidate for antiviral and antitumor agents against EBV and human gastric carcinoma

  13. Quercetin-induced apoptosis prevents EBV infection.

    PubMed

    Lee, Minjung; Son, Myoungki; Ryu, Eunhyun; Shin, Yu Su; Kim, Jong Gwang; Kang, Byung Woog; Cho, Hyosun; Kang, Hyojeung

    2015-05-20

    Epstein-Barr virus (EBV) is a human gamma-1 herpesvirus that establishes a lifelong latency in over 90% of the world's population. During latency, virus exists predominantly as a chromatin-associated, multicopy episome in the nuclei of a variety of tumor cells derived from B cells, T cells, natural killer (NK) cells, and epithelial cells. Licorice is the root of Glycyrrhiza uralensis or G. glabra that has traditionally cultivated in eastern part of Asia. Licorice was reported to have anti-viral, anti-inflammatory, anti-atopic, hepatoprotective, anti-neurodegenerative, anti-tumor, anti-diabetic effects and so forth. Quercetin and isoliquiritigenin are produced from licorice and highly similar in molecular structure. They have diverse bioactive effects such as antiviral activity, anti-asthmatic activity, anti-cancer activity, anti-inflammation activity, monoamine-oxidase inhibitor, and etc. To determine anti-EBV and anti-EBVaGC (Epstein-Barr virus associated gastric carcinoma) effects of licorice, we investigated antitumor and antiviral effects of quercetin and isoliquiritigenin against EBVaGC. Although both quercetin and isoliquiritigenin are cytotoxic to SNU719 cells, quercetin induced more apoptosis in SNU719 cells than isoliquiritigenin, more completely eliminated DNMT1 and DNMT3A expressions than isoliquiritigenin, and more strongly affects the cell cycle progression of SNU719 than isoliquiritigenin. Both quercetin and isoliquiritigenin induce signal transductions to stimulate apoptosis, and induce EBV gene transcription. Quercetin enhances frequency of F promoter use, whereas isoliquiritigenin enhances frequency of Q promoter use. Quercetin reduces EBV latency, whereas isoliquiritigenin increases the latency. Quercetin increases more the EBV progeny production, and inhibits more EBV infection than isoliquiritigenin. These results indicate that quercetin could be a promising candidate for antiviral and antitumor agents against EBV and human gastric carcinoma.

  14. Uptake of quercetin and quercetin 3-glucoside from whole onion and apple peel extracts by Caco-2 cell monolayers.

    PubMed

    Boyer, Jeanelle; Brown, Dan; Liu, Rui Hai

    2004-11-17

    Evidence suggests that regular consumption of fruits and vegetables may reduce the risk of chronic diseases, and phytochemicals from fruits and vegetables may be responsible for this health benefit. However, there is limited knowledge on the bioavailability of specific phytochemicals from whole fruits and vegetables. This study used Caco-2 cells to examine uptake of quercetin aglycon and quercetin 3-glucoside as purified compounds and from whole onion and apple peel extracts. Pure quercetin aglycon was absorbed by the Caco-2 cells in higher concentrations than quercetin 3-glucoside (p < 0.05). Caco-2 cells treated with quercetin 3-glucoside accumulated both quercetin 3-glucoside and quercetin. Caco-2 cells absorbed more onion quercetin aglycon than onion quercetin 3-glucoside (p < 0.05), and the percentage of onion quercetin absorbed was greater than that of pure quercetin, most likely due to enzymatic hydrolysis of quercetin 3-glucoside and other quercetin glucosides found in the onion by the Caco-2 cells. Caco-2 cells absorbed low levels of quercetin 3-glucoside from apple peel extracts, but quercetin aglycon absorption was not detected. Caco-2 cell homogenates demonstrated both lactase and glucosidase activities when incubated with lactose and quercetin 3-glucoside, respectively. This use of the Caco2 cell model appears to be a simple and useful system for studying bioavailability of whole food phytochemicals and may be used to assess differences in bioavailability between foods.

  15. Incorporation of quercetin in respirable lipid microparticles: effect on stability and cellular uptake on A549 pulmonary alveolar epithelial cells.

    PubMed

    Scalia, Santo; Trotta, Valentina; Traini, Daniela; Young, Paul M; Sticozzi, Claudia; Cervellati, Franco; Valacchi, Giuseppe

    2013-12-01

    The aim of the present study was to develop controlled release inhalable lipid microparticles (LMs) loaded with the antioxidant flavonoid, quercetin and to investigate the interaction of these microparticles with A549 pulmonary alveolar epithelial cells. The LMs were produced using different lipidic materials and surfactants, by melt emulsification followed by a sonication step. The most efficient modulation of the in vitro release of quercetin was achieved by the LMs prepared with tristearin and hydrogenated phosphatidylcholine, which were used for subsequent studies. These LMs exhibited a quercetin loading of 11.8±0.3%, and a volume median diameter, determined by laser diffraction, of 4.1±0.2μm. Moreover, their mass median aerodynamic diameter (4.82±0.15μm) and fine particle fraction (27.2±3.9%), as measured by multi-stage liquid impinger, were suitable for pulmonary delivery. Quercetin was found to be highly unstable (complete decomposition within 6-h incubation) in Ham's F-12 medium used for A549 cell culture. Degradation was markedly reduced (16.4% of the initial quercetin content still present after 24-h incubation) after encapsulation in the lipid particle system. Viability studies performed by lactate dehydrogenase assay, demonstrated that quercetin LMs showed no significant cytotoxicity on the A549 cells, over the concentration 0.1-5μM. The uptake of quercetin by the A549 lung alveolar cells was also investigated. After 4-h incubation, the accumulation of quercetin in the A549 cells was significantly higher (2.3-fold increase) for the microparticle entrapped flavonoid when compare to non-encapsulated quercetin. The enhanced intracellular delivery of quercetin achieved by the LMs is likely due to the flavonoid stabilization after encapsulation. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Discovering novel quercetin-3-O-amino acid-esters as a new class of Src tyrosine kinase inhibitors.

    PubMed

    Huang, He; Jia, Qi; Ma, Jingui; Qin, Guangrong; Chen, Yingyi; Xi, Yonghua; Lin, Liping; Zhu, Weiliang; Ding, Jian; Jiang, Hualiang; Liu, Hong

    2009-05-01

    Quercetin-3-O-amino acid-esters, a new type of quercetin derivatives, were successfully prepared for the first time. Different from quercetin, the novel compounds show higher selectivity as inhibitors against Src tyrosine kinase (IC(50) values ranging from 3.2 microM to 9.9 microM) than against EGFR tyrosine kinase. Molecular docking reveals that both hydrophobic and hydrogen bonding interactions are important to the selectivity. Therefore, this study provides a new promising scaffold for further development of new anticancer drugs targeting Src tyrosine kinase.

  17. Quercetin as a shuttle for labile iron.

    PubMed

    Baccan, Mayara Marinovic; Chiarelli-Neto, Orlando; Pereira, Regina Mara Silva; Espósito, Breno Pannia

    2012-02-01

    The antioxidant activity of flavonoids may involve their ability to complex body iron in non-redox-active forms. In this study, it was found that the catechol flavonoids rutin and quercetin are able to suppress redox-active labile plasma iron (LPI) in both buffered solution and in iron-overloaded sera. Both flavonoids are effective in loading the metal into the iron-transport protein transferrin. Iron derivatives of quercetin and rutin are able to permeate cell membranes, however, only free quercetin is able to gain access to the cytosol and decrease intracellular labile iron pools. These results suggest that the antioxidant activity of quercetin may be dependent on its ability to shuttle labile iron from cell compartments followed by its transfer to transferrin.

  18. Synthesis and Antiviral Activity of Substituted Quercetins

    PubMed Central

    Thapa, Mahendra; Kim, Yunjeong; Desper, John; Chang, Kyeong-Ok; Hua, Duy H.

    2011-01-01

    Influenza viruses are important pathogens that cause respiratory infections in humans and animals. In addition to vaccination, antiviral drugs against influenza virus play a significant role in controlling viral infections by reducing disease progression and virus transmission. Plant derived polyphenols are associated with antioxidant activity, anti-carcinogenic, and cardio- and neuro-protective actions. Some polyphenols, such as resveratrol and epigallocatechin gallate (EGCG), showed significant anti-influenza activity in vitro and/or in vivo. Recently we showed that quercetin and isoquercetin (quercetin-3-β-D-glucoside), a glucoside form of quercetin, significantly reduced the replication of influenza viruses in vitro and in vivo (isoquercetin). The antiviral effects of isoquercetin were greater than that of quercetin with lower IC50 values and higher in vitro therapeutic index. Thus, we investigated the synthesis and antiviral activities of various quercetin derivatives with substitution of C3, C3’, and C5 hydroxyl functions with various phenolic ester, alkoxy, and aminoalkoxy moieties. Among newly synthesized compounds, quercetin-3-gallate which is structurally related to EGCG showed comparable antiviral activity against influenza virus (porcine H1N1 strain) to that of EGCG with improved in vitro therapeutic index. PMID:22115591

  19. Synthesis and antiviral activity of substituted quercetins.

    PubMed

    Thapa, Mahendra; Kim, Yunjeong; Desper, John; Chang, Kyeong-Ok; Hua, Duy H

    2012-01-01

    Influenza viruses are important pathogens that cause respiratory infections in humans and animals. In addition to vaccination, antiviral drugs against influenza virus play a significant role in controlling viral infections by reducing disease progression and virus transmission. Plant derived polyphenols are associated with antioxidant activity, anti-carcinogenic, and cardio- and neuro-protective actions. Some polyphenols, such as resveratrol and epigallocatechin gallate (EGCG), showed significant anti-influenza activity in vitro and/or in vivo. Recently we showed that quercetin and isoquercetin (quercetin-3-β-d-glucoside), a glucoside form of quercetin, significantly reduced the replication of influenza viruses in vitro and in vivo (isoquercetin). The antiviral effects of isoquercetin were greater than that of quercetin with lower IC(50) values and higher in vitro therapeutic index. Thus, we investigated the synthesis and antiviral activities of various quercetin derivatives with substitution of C3, C3', and C5 hydroxyl functions with various phenolic ester, alkoxy, and aminoalkoxy moieties. Among newly synthesized compounds, quercetin-3-gallate which is structurally related to EGCG showed comparable antiviral activity against influenza virus (porcine H1N1 strain) to that of EGCG with improved in vitro therapeutic index. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Structural insights into the polypharmacological activity of quercetin on serine/threonine kinases.

    PubMed

    Baby, Bincy; Antony, Priya; Al Halabi, Walaa; Al Homedi, Zahrah; Vijayan, Ranjit

    2016-01-01

    Polypharmacology, the discovery or design of drug molecules that can simultaneously interact with multiple targets, is gaining interest in contemporary drug discovery. Serine/threonine kinases are attractive targets for therapeutic intervention in oncology due to their role in cellular phosphorylation and altered expression in cancer. Quercetin, a naturally occurring flavonoid, inhibits multiple cancer cell lines and is used as an anticancer drug in Phase I clinical trial. Quercetin glycosides have also received some attention due to their high bioavailability and activity against various diseases including cancer. However, these have been studied to a lesser extent. In this study, the structural basis of the multitarget inhibitory activity of quercetin and isoquercitrin, a glycoside derivative, on serine/threonine kinases using molecular modeling was explored. Structural analysis showed that both quercetin and isoquercitrin exhibited good binding energies and interacted with aspartate in the highly conserved Asp-Phe-Gly motif. The results indicate that isoquercitrin could be a more potent inhibitor of several members of the serine/threonine kinase family. In summary, the current structural evaluation highlights the multitarget inhibitory property of quercetin and its potential to be a chemical platform for oncological polypharmacology.

  1. Structural insights into the polypharmacological activity of quercetin on serine/threonine kinases

    PubMed Central

    Baby, Bincy; Antony, Priya; Al Halabi, Walaa; Al Homedi, Zahrah; Vijayan, Ranjit

    2016-01-01

    Polypharmacology, the discovery or design of drug molecules that can simultaneously interact with multiple targets, is gaining interest in contemporary drug discovery. Serine/threonine kinases are attractive targets for therapeutic intervention in oncology due to their role in cellular phosphorylation and altered expression in cancer. Quercetin, a naturally occurring flavonoid, inhibits multiple cancer cell lines and is used as an anticancer drug in Phase I clinical trial. Quercetin glycosides have also received some attention due to their high bioavailability and activity against various diseases including cancer. However, these have been studied to a lesser extent. In this study, the structural basis of the multitarget inhibitory activity of quercetin and isoquercitrin, a glycoside derivative, on serine/threonine kinases using molecular modeling was explored. Structural analysis showed that both quercetin and isoquercitrin exhibited good binding energies and interacted with aspartate in the highly conserved Asp–Phe–Gly motif. The results indicate that isoquercitrin could be a more potent inhibitor of several members of the serine/threonine kinase family. In summary, the current structural evaluation highlights the multitarget inhibitory property of quercetin and its potential to be a chemical platform for oncological polypharmacology. PMID:27729770

  2. The impact of quercetin on wound healing relates to changes in αV and β1 integrin expression.

    PubMed

    Doersch, Karen M; Newell-Rogers, M Karen

    2017-08-01

    Overly fibrotic wound healing can lead to excess scar formation, causing functional impairment and undesirable cosmetic results. However, there are few successful treatments available to prevent or remediate scars. This study sought to explore the molecular mechanisms by which quercetin, a naturally-occurring antifibrotic agent, diminishes scar formation. Using both mice and fibroblast cells, we examined quercetin's impact on fibrosis and the wound healing rate, and potential molecular mechanisms underlying the quercetin-mediated reduction of fibrosis. While cultured fibroblasts demonstrated normal growth in response to quercetin, quercetin increased surface αV integrin and decreased β1 integrin. These changes in surface integrin expression may impact factors that contribute to fibrosis including cell migration, proliferation, and extracellular matrix production. In both quercetin-treated and control mice, wounds healed in about 14 days. Masson's trichrome stain revealed diminished fibrosis at the wound site in quercetin-treated animals despite the normal healing rate, indicating the potential for better cosmetic results without delaying healing. An in vitro scratch wound model using cells plated on an artificial extracellular matrix demonstrated delayed closure following quercetin treatment. The extracellular matrix also ameliorated quercetin's effect on αV integrin. Thus, αV integrin recruitment in response to quercetin treatment may promote the quercetin-mediated decrease extracellular matrix because cells require less extracellular matrix to migrate into a wound. With added extracellular matrix, β1 integrin remained diminished in response to quercetin, indicating that quercetin's effect on β1 integrin expression is independent of extracellular matrix -mediated signaling and is likely driven by inhibition of the intracellular mechanisms driving β1 expression. These findings suggest that quercetin could alter the cells' interactions with the extracellular

  3. Biotinylated Quercetin as an Intrinsic Photoaffinity Proteomics Probe for the Identification of Quercetin Target Proteins

    PubMed Central

    Wang, Rongsheng E.; Hunt, Clayton R.; Chen, Jiawei; Taylor, John-Stephen

    2012-01-01

    Quercetin is a flavonoid natural product that is found in many foods and has been found to have a wide range of medicinal effects. Though a number of quercetin binding proteins have been identified, there has been no systematic approach to identifying all potential targets of quercetin. We describe an O7- biotinylated derivative of quercetin (BioQ) that can act as a photoaffinity proteomics reagent for capturing quercetin binding proteins, which can then be identified by LC MS/MS. BioQ was shown to inhibit heat induction of HSP70 with almost the same efficiency as quercetin, and to both inhibit and photocrosslink to CK2 kinase, a known target of quercetin involved in activation of the heat shock transcription factor. BioQ was also able to pull down a number of proteins from unheated and heated Jurkat cells following UV-irradiation that could be detected by both silver staining and Western blot analysis with an anti-biotin antibody. Analysis of the protein bands by trypsinization and LC MS/MS led to the identification of heat shock proteins HSP70 and HSP90 as possible quercetin target proteins, along with ubiquitin-activating enzyme, a spliceosomal protein, RuvB-like 2 ATPases, and eukaryotic translation initiation factor 3. In addition, a mitochondrial ATPase was identified that has been previously shown to be a target of quercetin. Most of the proteins identified have also been previously suggested to be potential anticancer targets, suggesting that quercetin's antitumor activity may be due to its ability to inhibit multiple target proteins. PMID:21798748

  4. Mesoporous silica as topical nanocarriers for quercetin: characterization and in vitro studies.

    PubMed

    Sapino, Simona; Ugazio, Elena; Gastaldi, Lucia; Miletto, Ivana; Berlier, Gloria; Zonari, Daniele; Oliaro-Bosso, Simonetta

    2015-01-01

    The flavonoid quercetin is extensively studied for its antioxidant and chemopreventive properties. However the poor water-solubility, low stability and short half-life could restrict its use in skin care products and therapy. The present study was aimed to evaluate the potential of aminopropyl functionalized mesoporous silica nanoparticles (NH2-MSN) as topical carrier system for quercetin delivery. Thermo gravimetric analysis, X-ray diffraction, high resolution transmission electron microscopy, nitrogen adsorption isotherms, FT-IR spectroscopy, zeta potential measurements and differential scanning calorimetry allowed analyzing with great detail the organic-inorganic molecular interaction. The protective effect of this vehicle on UV-induced degradation of the flavonoid was investigated revealing a certain positive influence of the inclusion on the photostability over time. Epidermal accumulation and transdermal permeation of this molecule were ex vivo evaluated using porcine skin mounted on Franz diffusion cells. The inclusion complexation with the inorganic nanoparticles increased the penetration of quercetin into the skin after 24h post-application without transdermal delivery. The effect of quercetin alone or given as complex with NH2-MSN on proliferation of JR8 human melanoma cells was evaluated by sulforhodamine B colorimetric proliferation assay. At a concentration 60 μM the complex with NH2-MSN was more effective than quercetin alone, causing about 50% inhibition of cell proliferation.

  5. Comparison of quercetin and dihydroquercetin: antioxidant-independent actions on erythrocyte and platelet membrane.

    PubMed

    Chen, Yifan; Deuster, Patricia

    2009-11-10

    We investigated the effects of two flavonoids quercetin and dihydroquercetin (DHQ), which have different solubilities and antioxidant capacities, on hemolysis and platelet aggregation in human blood. Exposure of human red blood cells (RBCs) to free radicals generated by 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) for 2h resulted in 63.5+/-3.9% hemolysis (vehicle: 0.3+/-0.4%). Pre-incubation of RBCs with lipid-soluble quercetin and water-soluble DHQ for 30min significantly reduced the AAPH-induced hemolysis to 3.6+/-1.5% and 32.5+/-5.6% respectively. In contrast, quercetin and DHQ were similarly effective in reducing phospholipase C-induced hemolysis (37.2+/-9.1% and 45.4+/-10.0% versus vehicle 75.7+/-5.2%, P<0.001). Pre-incubation with quercetin, but not DHQ, inhibited the aggregation of platelets by adenosine diphosphate. DHQ was more potent than quercetin in inhibiting superoxide produced by xanthine oxidase. These results suggest that the antihemolytic effects of flavonoids may not be directly mediated by removal of free radicals and may likely be due to their interaction with cell membrane.

  6. Quercetin-Iron Complex: Synthesis, Characterization, Antioxidant, DNA Binding, DNA Cleavage, and Antibacterial Activity Studies.

    PubMed

    Raza, Aun; Xu, Xiuquan; Xia, Li; Xia, Changkun; Tang, Jian; Ouyang, Zhen

    2016-11-01

    Quercetin-iron (II) complex was synthesized and characterized by elemental analysis, ultraviolet-visible spectrophotometry, fourier transform infrared spectroscopy, mass spectrometry, proton nuclear magnetic resonance spectroscopy, thermogravimetry and differential scanning calorimetry, scanning electron micrography and molar conductivity. The low molar conductivity value investigates the non-electrolyte nature of the complex. The elemental analysis and other physical and spectroscopic methods reveal the 1:2 stoichiometric ratio (metal:ligand) of the complex. Antioxidant study of the quercetin and its metal complex against 2, 2-di-phenyl-1-picryl hydrazyl radical showed that the complex has much more radical scavenging activity than free quercetin. The interaction of quercetin-iron (II) complex with DNA was determined using ultraviolet visible spectra, fluorescence spectra and agarose gel electrophoresis. The results showed that quercetin-iron (II) complex can intercalate moderately with DNA, quench a strong intercalator ethidium bromide and compete for the intercalative binding sites. The complex showed significant cleavage of pBR 322 DNA from supercoiled form to nicked circular form and these cleavage effects were dose-dependent. Moreover, the mechanism of DNA cleavage indicated that it was an oxidative cleavage pathway. These results revealed the potential nuclease activity of complex to cleave DNA. In addition, antibacterial activity of complex on E.coli and S. aureus was also investigated. The results showed that complex has higher antibacterial activity than ligand.

  7. Role of Quercetin Benefits in Neurodegeneration.

    PubMed

    Elumalai, Preetham; Lakshmi, Sreeja

    2016-01-01

    Neurodegenerative disorders are often life threatening and hired as an economic burden to the health-care system. Nutritional interventions principally involving polyphenols were practiced to arrest or reverse the age-related health disorders. Flavonoids, a class of dietary polyphenols, are rising to superstardom in preventing brain disorders with their potent antioxidant defense mechanism. Quercetin is a ubiquitous flavonoid reported to have all-natural myriad of health benefits. Citrus fruits, apple, onion, parsley, berries, green tea, and red wine comprise the major dietary supplements of quercetin apart from some herbal remedies like Ginkgo biloba. Appositeness of quercetin in reducing risks of neurodegenerative disorders, cancer, cardiovascular diseases, allergic disorders, thrombosis, atherosclerosis, hypertension, and arrhythmia, to name a few, is attributed to its highly pronounced antioxidant and anti-inflammatory properties. Neurodegeneration, characterized by progressive deterioration of the structure and function of neurons, is crucially accompanied by severe cognitive deficits. Aging is the major risk factor for neurodegenerative disorders in Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD) being coequal high hands. Oxidative stress and mitochondrial dysfunction are the key players in triggering neurodegeneration. The upsurge of neurodegenerative disorders is always appalling since there exists a paucity in effective treatment practices. Past few years' studies have underpinned the mechanisms through which quercetin boons the brain health in many aspects including betterment in cognitive output. Undoubtedly, quercetin will be escalating as an arable field, both in scientific research and in pharmacological and clinical applications.

  8. In silico analysis and molecular docking studies of potential angiotensin-converting enzyme inhibitor using quercetin glycosides

    PubMed Central

    Muhammad, Syed Aun; Fatima, Nighat

    2015-01-01

    The purpose of this study was to analyze the inhibitory action of quercetin glycosides by computational docking studies. For this, natural metabolite quercetin glycosides isolated from buckwheat and onions were used as ligand for molecular interaction. The crystallographic structure of molecular target angiotensin-converting enzyme (ACE) (peptidyl-dipeptidase A) was obtained from PDB database (PDB ID: 1O86). Enalapril, a well-known brand of ACE inhibitor was taken as the standard for comparative analysis. Computational docking analysis was performed using PyRx, AutoDock Vina option based on scoring functions. The quercetin showed optimum binding affinity with a molecular target (angiotensin-converting-enzyme) with the binding energy of −8.5 kcal/mol as compared to the standard (−7.0 kcal/mol). These results indicated that quercetin glycosides could be one of the potential ligands to treat hypertension, myocardial infarction, and congestive heart failure. PMID:26109757

  9. Visible Photoluminescence of Solid State Quercetin and Rutin

    NASA Astrophysics Data System (ADS)

    Zlateva, G.; Mileva, M.; Popdimitrova, N.

    2007-04-01

    Quercetin is found in many foods, as well as in seeds, nuts, flowers, barks, and leaves. It is the most abundant of the flavonoid molecules. Rutin is the sugar-containing homologue of quercetin - quercetin-3-rutinoside. Visible photoluminescence spectra of solid state quercetin and rutin are under attention in this paper. The spectra were obtained at wavelenght of excited light 457.9 nm.

  10. Characterization of sulfated quercetin and epicatechin metabolites.

    PubMed

    Dueñas, Montserrat; González-Manzano, Susana; Surco-Laos, Felipe; González-Paramas, Ana; Santos-Buelga, Celestino

    2012-04-11

    Different monosulfates of quercetin and epicatechin with metabolic interest were obtained by hemisynthesis and characterized regarding their chromatographic behavior and absorption and mass spectra. Three of these compounds were further isolated, and their structures were elucidated by mass spectrometry and (1)H and (13)C nuclear magnetic resonance using one- and two-dimensional techniques (heteronuclear single-quantum coherence and heteronuclear multiple-bond correlation). The calculation of the proton and carbon shifts caused by sulfation allowed for the assignment of the position of the sulfate group in the flavonoids, so that the compounds were identified as quercetin-3'-O-sulfate, quercetin 4'-O-sulfate, and epicatechin 4'-O-sulfate. It was found that sulfation at position 3' induced a large upfield shift in the carbon bearing the sulfate group and downfield displacements of the adjacent carbons, whereas no significant upfield or downfield shifts were observed with respect to the parent flavonoid when sulfation was produced at position 4'.

  11. Enhancement of oral bioavailability of rivastigmine with quercetin nanoparticles by inhibiting CYP3A4 and esterases.

    PubMed

    Palle, Suresh; Neerati, Prasad

    2017-04-01

    Quercetin is a well-known flavonoid, has pharmacokinetic interaction with ester drugs due to its capability of esterase inhibition in the gut and liver. However, the interaction between quercetin nanoparticles (NQC) and rivastigmine has not been reported. Hence, the present study was performed to evaluate the effect of quercetin alone and its nanoparticles on the pharmacokinetics of rivastigmine in rats. NQC prepared by antisolvent precipitation method. The influence of quercetin on the pharmacokinetics of rivastigmine was evaluated by following methods i.e. in vitro inhibitory effect on esterase enzyme in rat liver microsomes and in vitro assessment of CYP3A activity using erythromycin-N-demethylase (EMD) assay. To confirm these findings, an in vivo pharmacokinetic study of orally administered rivastigmine in rats with quercetin and NQC pretreatments was performed. The size of NQC was observed below 300nm. Quercetin significantly (p<0.05) inhibited the esterase-mediated metabolism of rivastigmine. In in vitro assessment of CYP3A activity model the erythromycin-N-demethylation (EMD) levels in quercetin treated group were significantly reduced (p<0.05). Cmax, AUC0-t and AUC0- ∞ of rivastigmine were found to be increased in quercetin and NQC pretreated groups. Further, the CL/F and Vd/F of rivastigmine were significantly decreased. The results revealed that enhanced bioavailability of rivastigmine might be caused by the combination of their effects due to CYP3A and esterase inhibition, Therefore, concomitant administration of NQC influences the bioavailability of rivastigmine and also has synergetic effect in the treatment of Alzheimer's disease. Copyright © 2016 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  12. Quercetin Aglycone Is Bioavailable in Murine Pancreas and Pancreatic Xenografts

    PubMed Central

    Zhang, Lifeng; Angst, Eliane; Park, Jenny L.; Moro, Aune; Dawson, David W.; Reber, Howard A.; Eibl, Guido; Hines, O. Joe; Go, Vay-Liang W.; Lu, Qing-Yi

    2010-01-01

    Quercetin is a potential chemopreventive and chemotherapeutic agent for pancreatic and other cancers. This study was to examine the distribution of quercetin in plasma, lung, liver, pancreas and pancreatic cancer xenografts in a murine in vivo model and the uptake of quercetin in pancreatic cancer MiaPaCa-2 cells in cellular in vitro model. Mice were randomly allocated to control diet, 0.2 and 1% quercetin diet groups utilizing the AIN93G-based diet (n=12 per group) for 6 weeks. In addition, 6 mice from each group were injected weekly with chemotherapeutic drug gemcitabine (120 mg/kg mouse, i.p.). MiaPaCa cells were collected from culture medium after cells were exposed to 30 µM of quercetin for 0.5, 1, 2, 4, 8, and 24 hrs. Levels of quercetin and 3-O’-methyl-quercetin in mice tissues and MiaPaCa-2 cells were measured by high-pressure liquid chromatography following enzymatic hydrolysis and then extraction. Our study showed that quercetin is accumulated in pancreatic cancer cells, and is absorbed in the circulating system, tumors and tissues of pancreas, liver and lung in vivo. A higher proportion of total quercetin found in tumors and pancreas are aglycones. Gemcitabine co-treatment with quercetin reduced absorption of quercetin in mice circulatory system and liver. Results from the study provide important information on the interpretation of chemo-therapeutic efficacy of quercetin. PMID:20499918

  13. Bioavailability of the flavonol quercetin in neonatal calves after oral administration of quercetin aglycone or rutin.

    PubMed

    Maciej, J; Schäff, C T; Kanitz, E; Tuchscherer, A; Bruckmaier, R M; Wolffram, S; Hammon, H M

    2015-06-01

    Polyphenols, such as flavonoids, are secondary plant metabolites with potentially health-promoting properties. In newborn calves flavonoids may improve health status, but little is known about the systemically availability of flavonoids in calves to exert biological effects. The aim of this study was to investigate the oral bioavailability of the flavonol quercetin, applied either as quercetin aglycone (QA) or as its glucorhamnoside rutin (RU), in newborn dairy calves. Twenty-one male newborn German Holstein calves were fed equal amounts of colostrum and milk replacer according to body weight. On d 2 and 29 of life, 9 mg of quercetin equivalents/kg of body weight, either fed as QA or as RU, or no quercetin (control group) were fed together with the morning meal. Blood samples were taken before and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 12, 24, and 48 h after feed intake. Quercetin and quercetin metabolites with an intact flavonol structure (isorhamnetin, tamarixetin, and kaempferol) were analyzed in blood plasma after treatment with glucuronidase or sulfatase by HPLC with fluorescence detection. Maximum individual plasma concentration was depicted from the concentration-time-curve on d 2 and 29, respectively. Additional blood samples were taken to measure basal plasma concentrations of total protein, albumin, urea, and lactate as well as pre- and postprandial plasma concentrations of glucose, nonesterified fatty acids, insulin, and cortisol. Plasma concentrations of quercetin and its metabolites were significantly higher on d 2 than on d 29 of life, and administration of QA resulted in higher plasma concentrations of quercetin and its metabolites than RU. The relative bioavailability of total flavonols (sum of quercetin and its metabolites isorhamnetin, tamarixetin, and kaempferol) from RU was 72.5% on d 2 and 49.6% on d 29 when compared with QA (100%). Calves fed QA reached maximum plasma concentrations of total flavonols much earlier than did RU-fed calves. Plasma

  14. Modulation of mammalian sperm motility by quercetin.

    PubMed

    Nass-Arden, L; Breitbart, H

    1990-04-01

    The flavonoid quercetin inhibits collective motility of ejaculated ram spermatozoa in the first 2 hr of incubation; during the next 3-4 hr motility is stimulated. To explain this interesting effect, we followed the influence of quercetin on sperm glycolysis, extracellular pH, ATP content, mitochondrial respiration, and lipid peroxidation. The collective motility of untreated cells is decreased to about 40% of the original motility during two hours of incubation. During this time, the rate of glycolysis is constant, respiration rate is increasing, there is no change in ATP content, the rate of lipid peroxidation is very slow, and the extracellular pH became very acidic (pH 5.5). It is concluded that motility is decreased due to this acidification. This acidification is prevented to some extent by quercetin, which indirectly inhibits glycolysis. Quercetin inhibits motility due to the inhibition of the plasma membrane calcium pump, as we showed previously (Breitbart et al., J Biol Chem 260:11548-11553, 1985). The motility of untreated cells is arrested after 3.5 hr of incubation, whereas quercetin-treated cells show high motility, which continues for additional 2-3 hr. After 3.5 hr, the control cells show no glycolytic activity, ATP content and respiration rates are decreased, and rate of lipid peroxidation is highly increased. At this time, quercetin-treated cells show no glycolytic activity, only a small decrease in ATP content and respiratory rate, and a very low rate of lipid peroxidation. Based on these data it is concluded that sperm motility after 3.5 hr of incubation is dependent mainly on mitochondrial respiration.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. In vitro digestion and lactase treatment influence uptake of quercetin and quercetin glucoside by the Caco-2 cell monolayer

    PubMed Central

    Boyer, Jeanelle; Brown, Dan; Liu, Rui Hai

    2005-01-01

    Background Quercetin and quercetin glycosides are widely consumed flavonoids found in many fruits and vegetables. These compounds have a wide range of potential health benefits, and understanding the bioavailability of flavonoids from foods is becoming increasingly important. Methods This study combined an in vitro digestion, a lactase treatment and the Caco-2 cell model to examine quercetin and quercetin glucoside uptake from shallot and apple homogenates. Results The in vitro digestion alone significantly decreased quercetin aglycone recovery from the shallot digestate (p < 0.05), but had no significant effect on quercetin-3-glucoside recovery (p > 0.05). Digestion increased the Caco-2 cell uptake of shallot quercetin-4'-glucoside by 2-fold when compared to the non-digested shallot. Despite the loss of quercetin from the digested shallot, the bioavailability of quercetin aglycone to the Caco-2 cells was the same in both the digested and non-digested shallot. Treatment with lactase increased quercetin recovery from the shallot digestate nearly 10-fold and decreased quercetin-4'-glucoside recovery by more than 100-fold (p < 0.05), but had no effect on quercetin recovery from apple digestates. Lactase treatment also increased shallot quercetin bioavailability to the Caco-2 cells approximately 14-fold, and decreased shallot quercetin-4'-glucoside bioavailability 23-fold (p < 0.05). These Caco-2 cells had lactase activity similar to that expressed by a lactose intolerant human. Conclusions The increase in quercetin uptake following treatment with lactase suggests that dietary supplementation with lactase may increase quercetin bioavailability in lactose intolerant humans. Combining the digestion, the lactase treatment and the Caco-2 cell culture model may provide a reliable in vitro model for examining flavonoid glucoside bioavailability from foods. PMID:15644141

  16. Intracellular ROS protection efficiency and free radical-scavenging activity of quercetin and quercetin-encapsulated liposomes.

    PubMed

    Rezaei-Sadabady, Rogaie; Eidi, Akram; Zarghami, Nosratollah; Barzegar, Abolfazl

    2016-01-01

    Quercetin (3,5,7,3',4'-pentahydroxyflavone) is a natural bio-flavonoid originating from fruits, vegetables, seeds, berries, and tea. The antioxidant activity of quercetin and its protective effects against cardiovascular disorders, anti-cancer, anti-inflammatory, and anti-viral activities have been extensively documented; however, the clinical request of quercetin in cancer treatment is significantly limited due to its very poor delivery features. In order to increase the hydrophilicity and drug delivery capability, we encapsulated quercetin into liposomes. Our data indicated that liposomal quercetin can significantly improve the solubility and bioavailability of quercetin and can be used as an effective antioxidant for ROS protection within the polar cytoplasm, and the nano-sized quercetin encapsulated by liposomes enhanced the cellular uptake (cancer cell human MCF_7). Quercetin has many pharmaceutical applications, many of which arise from its potent antioxidant properties. The present research examined the antioxidant activities of quercetin in polar solvents by a comparative study using reduction of ferric iron in aqueous medium, intracellular ROS/toxicity assays, and reducing DPPH assays. Cell viability and ROS assays demonstrated that quercetin was able to penetrate into the polar medium inside the cells and to protect them against the highly toxic and deadly belongings of cumene hydroperoxide. The purpose of this study was to determine whether a liposomal formulation of quercetin can suggestively improve its solubility and bioavailability and can be a possible request in the treatment of tumor. The authors encapsulated quercetin in a liposomal delivery system. They studied the in vitro effects of this compound on proliferation using human MCF-7 carcinoma cells. The activity of liposomal quercetin was equal to or better than that of free quercetin at equimolar concentrations. Our data indicated that liposomal quercetin can significantly improve the

  17. Higher plasma quercetin levels following oral administration of an onion skin extract compared with pure quercetin dihydrate in humans.

    PubMed

    Burak, Constanze; Brüll, Verena; Langguth, Peter; Zimmermann, Benno F; Stoffel-Wagner, Birgit; Sausen, Udo; Stehle, Peter; Wolffram, Siegfried; Egert, Sarah

    2017-02-01

    To investigate the plasma kinetics of quercetin derived from hard capsules filled with onion skin extract powder or quercetin dihydrate in humans. In a randomized, single-blind, diet-controlled crossover study, 12 healthy subjects (six men and six women) aged 21-33 years were administered a single oral supra-nutritional dose of approximately 163 mg quercetin derived from onion skin extract powder (containing 95.3 % of total flavonoids as quercetin aglycone) or quercetin dihydrate (134 mg quercetin aglycone equivalent). Blood samples were collected before and during a 24-h period after quercetin administration. The concentrations of quercetin and its two monomethylated derivatives, isorhamnetin (3'-O-methyl quercetin), and tamarixetin (4'-O-methyl quercetin), were measured using HPLC with fluorescence detection after plasma enzymatic treatment. The systemic availability, determined by comparing the plasma concentration-time curves of quercetin, was 4.8 times higher, and the maximum plasma concentration (C max) was 5.4 times higher after ingestion of the onion skin extract than after ingestion of pure quercetin dihydrate. By contrast, t max did not differ significantly between the two formulations. The C max values for isorhamnetin and tamarixetin were 3.8 and 4.4 times higher, respectively, after administration of onion skin extract than after pure quercetin dihydrate. The plasma kinetics of quercetin were not significantly different in men and women. Quercetin aglycone derived from onion skin extract powder is significantly more bioavailable than that from quercetin dihydrate powder filled hard capsules.

  18. In vitro digestion and lactase treatment influence uptake of quercetin and quercetin glucoside by the Caco-2 cell monolayer.

    PubMed

    Boyer, Jeanelle; Brown, Dan; Liu, Rui Hai

    2005-01-11

    Quercetin and quercetin glycosides are widely consumed flavonoids found in many fruits and vegetables. These compounds have a wide range of potential health benefits, and understanding the bioavailability of flavonoids from foods is becoming increasingly important. This study combined an in vitro digestion, a lactase treatment and the Caco-2 cell model to examine quercetin and quercetin glucoside uptake from shallot and apple homogenates. The in vitro digestion alone significantly decreased quercetin aglycone recovery from the shallot digestate (p < 0.05), but had no significant effect on quercetin-3-glucoside recovery (p > 0.05). Digestion increased the Caco-2 cell uptake of shallot quercetin-4'-glucoside by 2-fold when compared to the non-digested shallot. Despite the loss of quercetin from the digested shallot, the bioavailability of quercetin aglycone to the Caco-2 cells was the same in both the digested and non-digested shallot. Treatment with lactase increased quercetin recovery from the shallot digestate nearly 10-fold and decreased quercetin-4'-glucoside recovery by more than 100-fold (p < 0.05), but had no effect on quercetin recovery from apple digestates. Lactase treatment also increased shallot quercetin bioavailability to the Caco-2 cells approximately 14-fold, and decreased shallot quercetin-4'-glucoside bioavailability 23-fold (p < 0.05). These Caco-2 cells had lactase activity similar to that expressed by a lactose intolerant human. The increase in quercetin uptake following treatment with lactase suggests that dietary supplementation with lactase may increase quercetin bioavailability in lactose intolerant humans. Combining the digestion, the lactase treatment and the Caco-2 cell culture model may provide a reliable in vitro model for examining flavonoid glucoside bioavailability from foods.

  19. Characterization of citrate capped gold nanoparticle-quercetin complex: Experimental and quantum chemical approach

    NASA Astrophysics Data System (ADS)

    Pal, Rajat; Panigrahi, Swati; Bhattacharyya, Dhananjay; Chakraborti, Abhay Sankar

    2013-08-01

    Quercetin and several other bioflavonoids possess antioxidant property. These biomolecules can reduce the diabetic complications, but metabolize very easily in the body. Nanoparticle-mediated delivery of a flavonoid may further increase its efficacy. Gold nanoparticle is used by different groups as vehicle for drug delivery, as it is least toxic to human body. Prior to search for the enhanced efficacy, the gold nanoparticle-flavonoid complex should be prepared and well characterized. In this article, we report the interaction of gold nanoparticle with quercetin. The interaction is confirmed by different biophysical techniques, such as Scanning Electron Microscope (SEM), Circular Dichroism (CD), Fourier-Transform InfraRed (FT-IR) spectroscopy and Thermal Gravimetric Analysis (TGA) and cross checked by quantum chemical calculations. These studies indicate that gold clusters are covered by citrate groups, which are hydrogen bonded to the quercetin molecules in the complex. We have also provided evidences how capping is important in stabilizing the gold nanoparticle and further enhances its interaction with other molecules, such as drugs. Our finding also suggests that gold nanoparticle-quercetin complex can pass through the membranes of human red blood cells.

  20. Preparation and characterization of quercetin/dietary fiber nanoformulations.

    PubMed

    Khor, Chia Miang; Ng, Wai Kiong; Chan, Kok Ping; Dong, Yuancai

    2017-04-01

    Quercetin is well known for its beneficial health effects on the human body. However, the slow dissolution rate leading to poor bioavailability constitutes a barrier to being further developed for nutritional products. In this work, quercetin was co-precipitated with dietary fibers into a fast-dissolving nanoformulation via antisolvent precipitation, followed by spray drying. With the help of cellulose fiber, resistant starch or resistant maltodextrin, a high dissolution rate and good storage stability was achieved for quercetin nanoformulations. In addition, nanoformulations exhibited higher level of antioxidant activities in contrast to raw quercetin. The developed quercetin/dietary fiber nanoformulations could be used as supplements or functional ingredients for food development.

  1. Preparation of amino-modified active carbon cartridges and their use in the extraction of quercetin from Oldenlandia diffusa.

    PubMed

    Zhu, Tao; Row, Kyung Ho

    2011-12-05

    Polyethyleneimine (PEI) and ethylenediamine (EDA) as modifiers were bonded on active carbon (AC) surface for specific selective extraction of quercetin from Oldenlandia diffusa. The characteristics of the modified AC materials that were obtained were investigated by field emission-scanning electron microscopy (FE-SEM) and Fourier transform infrared spectrometer (FT-IR). The interactions between quercetin and the AC materials were investigated by fitting the static adsorption data to four linear and nonlinear adsorption isotherm models. Of these four models, the Langmuir-Freundlich adsorption isotherm was proved the best for investigating quercetin on AC materials. Scatchard analysis was used to evaluate the binding properties of the AC materials for quercetin. Solvent extraction and solid-phase extraction (SPE) were optimized, and the effect of the mobile phase pH was investigated to improve the performance for the separation of quercetin on high performance liquid chromatography (HPLC). The results from the validation of the proposed analytical method demonstrated that the EDA-modified AC was the most suitable SPE cartridge for the purification of quercetin from O. diffusa. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Gamma irradiation enhanced Tollip-mediated anti-inflammatory action through structural modification of quercetin in lipopolysaccharide-stimulated macrophages.

    PubMed

    Byun, Eui-Baek; Jang, Beom-Su; Kim, Hye-Min; Yang, Mi-So; Sung, Nak-Yun; Byun, Eui-Hong

    2017-01-01

    The changes in molecular structure and anti-inflammatory action of a gamma-irradiated quercetin were examined. Quercetin was gamma-irradiated at doses of 0, 15, 30, 50, 100 and 150kGy, which induced new radiolytic peaks (the highest radiolytic peak at a dose of 30kGy). Treatment of intact- and gamma-irradiated quercetin did not induce a significant cellular toxicity of macrophages at concentrations ranging from 12.5 to 50μM. Treatment of LPS-stimulated macrophages with gamma-irradiated quercetin (30kGy) showed a higher inhibitory action than intact-quercetin groups in the excessive expression of inducible nitric oxide synthases-mediated nitric oxide, prostaglandin E2, pro-inflammatory cytokines level, such as tumor necrosis factor-α, interleukin-6 and interleukin-1β, reactive oxygen species, as well as cell surface molecules (CD80, CD86, and MHC class I/II). The inhibition of LPS-stimulated pro-inflammatory mediators was mediated through a suppression of mitogen-activated protein kinases and nuclear factor-κB pathways. In addition, gamma-irradiated quercetin (30kGy) markedly elevated the expression of the Toll-interacting protein compared to intact-quercetin. The inhibitory action of intact- and gamma-irradiated quercetin on the production of IL-6 and TNF-α was not observed in the down-regulation of Tollip. Therefore, these findings represent new insights into the understanding of the changes in molecular structure and the physiological properties of natural products through the application of radiation technology. Copyright © 2016. Published by Elsevier B.V.

  3. Therapeutic effect of quercetin in collagen-induced arthritis.

    PubMed

    Haleagrahara, Nagaraja; Miranda-Hernandez, Socorro; Alim, Md Abdul; Hayes, Linda; Bird, Guy; Ketheesan, Natkunam

    2017-03-22

    Quercetin, a bioactive flavonoid with anti-inflammatory, immunosuppressive, and protective properties, is a potential agent for the treatment of rheumatoid arthritis (RA). Collagen-induced arthritis (CIA) is the most commonly used animal model for studying the pathogenesis of RA. This study analysed the therapeutic role of quercetin in collagen-induced arthritis in C57BL/6 mice. The animals were allocated into five groups that were subjected to the following treatments: negative (untreated) control, positive control (arthritis-induced), arthritis+methotrexate, arthritis+quercetin, and arthritis+methotrexate+quercetin. Assessments of weight, oedema, joint damage, and cytokine production were used to determine the therapeutic effect of quercetin. This study demonstrated for the first time the anti-inflammatory and protective effects of quercetin in vivo in CIA. The results also showed that the concurrent administration of quercetin and methotrexate did not offer greater protection than the administration of a single agent. The use of quercetin as a monotherapeutic agent resulted in the lowest degree of joint inflammation and the highest protection. The reduced severity of the disease in animals treated with quercetin was associated with decreased levels of TNF-α, IL-1β, IL-17, and MCP-1. In conclusion, this study determined that quercetin, which was non-toxic, produced better results than methotrexate for the protection of joints from arthritic inflammation in mice. Quercetin may be an alternative treatment for RA because it modulates the main pathogenic pathways of RA.

  4. The Flavonoid Quercetin Reverses Pulmonary Hypertension in Rats

    PubMed Central

    Moreno, Enrique; Moral-Sanz, Javier; Barreira, Bianca; Galindo, Pilar; Pandolfi, Rachele; Jimenez, Rosario; Moreno, Laura; Cogolludo, Angel; Duarte, Juan; Perez-Vizcaino, Francisco

    2014-01-01

    Quercetin is a dietary flavonoid which exerts vasodilator, antiplatelet and antiproliferative effects and reduces blood pressure, oxidative status and end-organ damage in humans and animal models of systemic hypertension. We hypothesized that oral quercetin treatment might be protective in a rat model of pulmonary arterial hypertension. Three weeks after injection of monocrotaline, quercetin (10 mg/kg/d per os) or vehicle was administered for 10 days to adult Wistar rats. Quercetin significantly reduced mortality. In surviving animals, quercetin decreased pulmonary arterial pressure, right ventricular hypertrophy and muscularization of small pulmonary arteries. Classic biomarkers of pulmonary arterial hypertension such as the downregulated expression of lung BMPR2, Kv1.5, Kv2.1, upregulated survivin, endothelial dysfunction and hyperresponsiveness to 5-HT were unaffected by quercetin. Quercetin significantly restored the decrease in Kv currents, the upregulation of 5-HT2A receptors and reduced the Akt and S6 phosphorylation. In vitro, quercetin induced pulmonary artery vasodilator effects, inhibited pulmonary artery smooth muscle cell proliferation and induced apoptosis. In conclusion, quercetin is partially protective in this rat model of PAH. It delayed mortality by lowering PAP, RVH and vascular remodeling. Quercetin exerted effective vasodilator effects in isolated PA, inhibited cell proliferation and induced apoptosis in PASMCs. These effects were associated with decreased 5-HT2A receptor expression and Akt and S6 phosphorylation and partially restored Kv currents. Therefore, quercetin could be useful in the treatment of PAH. PMID:25460361

  5. Quercetin modulates keratoconus metabolism in vitro

    PubMed Central

    McKay, Tina B; Sarker-Nag, Akhee; Lyon, Desiree’; Asara, John M; Karamichos, Dimitrios

    2016-01-01

    Corneal scarring is the result of a disease, infection or injury. The resulting scars cause significant loss of vision or even blindness. To-date, the most successful treatment is corneal transplantation, but it does not come without side effects. One of the corneal dystrophies that are correlated with corneal scarring is keratoconus (KC). The onset of the disease is still unknown; however, altered cellular metabolism has been linked to promoting the fibrotic phenotype and therefore scarring. We have previously shown that human keratoconus cells (HKCs) have altered metabolic activity when compared to normal human corneal fibroblasts (HCFs). In our current study, we present evidence that quercetin, a natural flavonoid, is a strong candidate for regulating metabolic activity of both HCFs and HKCs in vitro and therefore a potential therapeutic to target the altered cellular metabolism characteristic of HKCs. Targeted mass spectrometry-based metabolomics was performed on HCFs and HKCs with and without quercetin treatment in order to identify variations in metabolite flux. Overall, our study reveals a novel therapeutic target OF Quercetin on corneal stromal cell metabolism in both healthy and diseased states. Clearly, further studies are necessary in order to dissect the mechanism of action of quercetin. PMID:26173740

  6. Quercetin suppresses lung cancer growth by targeting Aurora B kinase.

    PubMed

    Xingyu, Zhu; Peijie, Ma; Dan, Peng; Youg, Wang; Daojun, Wang; Xinzheng, Chen; Xijun, Zhang; Yangrong, Song

    2016-11-01

    aurora B kinase is highly expressed in several cancer cells and promotes tumorigenesis and progression, and therefore, it is an important target for drug to treat tumors. Quercetin was identified to be an antitumor agent. Herein, we report for the first time that quercetin inhibited aurora B activities by directly binding with aurora B in vitro and in vivo. Ex vivo studies showed that quercetin inhibited aurora B activities in JB6 Cl41 cells and A549 lung cancer cells. Moreover, knockdown of aurora B in A549 cells decreased their sensitivities to quercetin. In vivo study demonstrated that injection of quercetin in A549 tumor-bearing mice effectively suppressed cancer growth. The phosphorylation of histone 3 in tumor tissues was also decreased after quercetin treatment. In short, quercetin can suppress growth of lung cancer cells as an aurora B inhibitor both in vitro and in vivo.

  7. Quercetin-imprinted chromatographic sorbents revisited: optimization of synthesis and rebinding protocols for application to natural resources.

    PubMed

    Pardo, Antonelle; Mespouille, Laetitia; Blankert, Bertrand; Trouillas, Patrick; Surin, Mathieu; Dubois, Philippe; Duez, Pierre

    2014-10-17

    Molecularly imprinted polymers (MIPs) based on quercetin and synthesized by either bulk, precipitation or suspension polymerization were characterized in terms of size and shape by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After a study of rebinding protocols, the optimal materials were evaluated as sorbents for solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) to confirm the presence of imprinted cavities and to assess their selectivity. Besides quercetin, other structurally related natural compounds, naringenin, daidzein and curcumin, were employed for selectivity tests of MIPs. Although rebinding protocols previously described for such MIPs are typically based on binding, washing and eluting methanol-based solutions, we show that this highly polar solvent leads to weak specific interactions (imprinting factor<1) and poor sorbent properties, most probably because of hydrogen-bonding interferences between the MIP and MeOH. Similar experiments performed in tetrahydrofuran yield to much more improved properties (imprinting factor>2.4). This calls for reviewing most of previously published data on quercetin-MIPs; in proper binding conditions, published MIPs may prove more performing than initially assessed. As expected, tested MIPs exhibited the highest selective rebinding towards quercetin template (imprinting effect, quercetin, 3.41; naringenin, 1.54; daidzein, 1.38; curcumin, 1.67); the differences in selectivity between quercetin analogues were explained by the ligand geometries and H-bonding patterns obtained from quantum-chemical calculations. The evaluation of MIPs under identical analytical conditions allowed investigating the effect of the production method on chromatographic performances. The MIPs in bead materials (for quercetin, peak width, 0.69; number of theoretical plates, 143; symmetry factor, 2.22) provided a significant improvement in chromatographic efficiency over the bulk materials

  8. A possible therapeutic potential of quercetin through inhibition of μ-calpain in hypoxia induced neuronal injury: a molecular dynamics simulation study

    PubMed Central

    Pandey, Anand Kumar; Shukla, Swet Chand; Bhattacharya, Pallab; Patnaik, Ranjana

    2016-01-01

    The neuroprotective property of quercetin is well reported against hypoxia and ischemia in past studies. This property of quercetin lies in its antioxidant property with blood-brain barrier permeability and anti-inflammatory capabilities. µ-Calpain, a calcium ion activated intracellular cysteine protease causes serious cellular insult, leading to cell death in various pathological conditions including hypoxia and ischemic stroke. Hence, it may be considered as a potential drug target for the treatment of hypoxia induced neuronal injury. As the inhibitory property of µ-calpain is yet to be explored in details, hence, in the present study, we investigated the interaction of quercetin with µ-calpain through a molecular dynamics simulation study as a tool through clarifying the molecular mechanism of such inhibition and determining the probable sites and modes of quercetin interaction with the µ-calpain catalytic domain. In addition, we also investigated the structure-activity relationship of quercetin with μ-calpain. Affinity binding of quercetin with µ-calpain had a value of –28.73 kJ/mol and a Ki value of 35.87 µM that may be a probable reason to lead to altered functioning of µ-calpain. Hence, quercetin was found to be an inhibitor of µ-calpain which might have a possible therapeutic role in hypoxic injury. PMID:27651771

  9. TRAIL apoptosis is enhanced by quercetin through Akt dephosphorylation.

    PubMed

    Kim, Young-Ho; Lee, Yong J

    2007-03-01

    TNF-related apoptosis-inducing ligand (TRAIL) is a promising cancer therapy that preferentially induces apoptosis in cancer cells. However, many neoplasms are resistant to TRAIL by mechanisms that are poorly understood. Here we demonstrated that human prostate cancer cells, but not normal prostate cells, are dramatically sensitized to TRAIL-induced apoptosis and caspase activation by quercetin. Quercetin, a ubiquitous bioactive plant flavonoid, has been shown to inhibit the proliferation of cancer cells. We have shown that quercetin can potentiate TRAIL-induced apoptotic death. Human prostate adenocarcinoma DU-145 and LNCaP cells were treated with various concentrations of TRAIL (10-200 ng/ml) and/or quercetin (10-200 microM) for 4 h. Quercetin, which caused no cytotoxicity by itself, promoted TRAIL-induced apoptosis. The TRAIL-mediated activation of caspase, and PARP (poly(ADP-ribose) polymerase) cleavage were both enhanced by quercetin. Western blot analysis showed that combined treatment with TRAIL and quercetin did not change the levels of TRAIL receptors (death receptors DR4 and DR5, and DcR2 (decoy receptor 2)) or anti-apoptotic proteins (FLICE-inhibitory protein (FLIP), inhibitor of apoptosis (IAP), and Bcl-2). However, quercetin promoted the dephosphorylation of Akt. Quercetin-induced potent inhibition of Akt phosphorylation. Taken together, the present studies suggest that quercetin enhances TRAIL-induced cytotoxicity by activating caspases and inhibiting phosphorylation of Akt.

  10. Quercetin induces autophagy via FOXO1-dependent pathways and autophagy suppression enhances quercetin-induced apoptosis in PASMCs in hypoxia.

    PubMed

    He, Yuanzhou; Cao, Xiaopei; Guo, Pujian; Li, Xiaochen; Shang, Huihui; Liu, Jin; Xie, Min; Xu, Yongjian; Liu, Xiansheng

    2017-02-01

    Quercetin, an important dietary flavonoid has been demonstrated to potentially reverse or even prevent pulmonary arterial hypertension (PAH) progression. However, the effects of quercetin on apoptosis and autophagy in pulmonary arterial smooth muscle cells (PASMCs) have not yet been clearly elucidated. The current study found that quercetin significantly induce the apoptotic and autophagic capacities of PASMCs in vitro and in vivo in hypoxia. In addition, we found that quercetin increases FOXO1 (a major mediator in autophagy regulation) expression and transcriptional activity. Moreover, FOXO1 knockdown by siRNAs inhibited the phosphorylation of mTOR and 4E-BPI, which is downstream of P70-S6K, and markedly blocked quercetin-induced autophagy. We also observed that FOXO1-mediated autophagy was achieved via SESN3 not Rictor upregulation and after mTOR suppression. Furthermore, Treatment with autophagy-specific inhibitors could markedly enhance quercetin-induced apoptosis in PASMCs under hypoxia. Finally, quercetin in combination with autophagy inhibition treatment could enhance the therapeutic effects of quercetin in hypoxia-associated PAH in vivo. Taken together, quercetin could enhance hypoxia-induced autophagy through the FOXO1-SENS3-mTOR pathway in PASMCs. Combining quercetin and autophagy inhibitors may be a novel therapeutic strategy for treating hypoxia-associated PAH. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Quercetin as an Antiviral Agent Inhibits Influenza A Virus (IAV) Entry

    PubMed Central

    Wu, Wenjiao; Li, Richan; Li, Xianglian; He, Jian; Jiang, Shibo; Liu, Shuwen; Yang, Jie

    2015-01-01

    Influenza A viruses (IAVs) cause seasonal pandemics and epidemics with high morbidity and mortality, which calls for effective anti-IAV agents. The glycoprotein hemagglutinin of influenza virus plays a crucial role in the initial stage of virus infection, making it a potential target for anti-influenza therapeutics development. Here we found that quercetin inhibited influenza infection with a wide spectrum of strains, including A/Puerto Rico/8/34 (H1N1), A/FM-1/47/1 (H1N1), and A/Aichi/2/68 (H3N2) with half maximal inhibitory concentration (IC50) of 7.756 ± 1.097, 6.225 ± 0.467, and 2.738 ± 1.931 μg/mL, respectively. Mechanism studies identified that quercetin showed interaction with the HA2 subunit. Moreover, quercetin could inhibit the entry of the H5N1 virus using the pseudovirus-based drug screening system. This study indicates that quercetin showing inhibitory activity in the early stage of influenza infection provides a future therapeutic option to develop effective, safe and affordable natural products for the treatment and prophylaxis of IAV infections. PMID:26712783

  12. Fast-Dissolving Core-Shell Composite Microparticles of Quercetin Fabricated Using a Coaxial Electrospray Process

    PubMed Central

    Li, Chen; Yu, Deng-Guang; Williams, Gareth R.; Wang, Zhuan-Hua

    2014-01-01

    This study reports on novel fast-dissolving core-shell composite microparticles of quercetin fabricated using coaxial electrospraying. A PVC-coated concentric spinneret was developed to conduct the electrospray process. A series of analyses were undertaken to characterize the resultant particles in terms of their morphology, the physical form of their components, and their functional performance. Scanning and transmission electron microscopies revealed that the microparticles had spherical morphologies with clear core-shell structure visible. Differential scanning calorimetry and X-ray diffraction verified that the quercetin active ingredient in the core and sucralose and sodium dodecyl sulfate (SDS) excipients in the shell existed in the amorphous state. This is believed to be a result of second-order interactions between the components; these could be observed by Fourier transform infrared spectroscopy. In vitro dissolution and permeation studies showed that the microparticles rapidly released the incorporated quercetin within one minute, and had permeation rates across the sublingual mucosa around 10 times faster than raw quercetin. PMID:24643072

  13. Fast Disintegrating Quercetin-Loaded Drug Delivery Systems Fabricated Using Coaxial Electrospinning

    PubMed Central

    Li, Xiao-Yan; Li, Yan-Chun; Yu, Deng-Guang; Liao, Yao-Zu; Wang, Xia

    2013-01-01

    The objective of this study is to develop a structural nanocomposite of multiple components in the form of core-sheath nanofibres using coaxial electrospinning for the fast dissolving of a poorly water-soluble drug quercetin. Under the selected conditions, core-sheath nanofibres with quercetin and sodium dodecyl sulphate (SDS) distributed in the core and sheath part of nanofibres, respectively, were successfully generated, and the drug content in the nanofibres was able to be controlled simply through manipulating the core fluid flow rates. Field emission scanning electron microscope (FESEM) images demonstrated that the nanofibres prepared from the single sheath fluid and double core/sheath fluids (with core-to-sheath flow rate ratios of 0.4 and 0.7) have linear morphology with a uniform structure and smooth surface. The TEM images clearly demonstrated the core-sheath structures of the produced nanocomposites. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) results verified that quercetin and SDS were well distributed in the polyvinylpyrrolidone (PVP) matrix in an amorphous state, due to the favourite second-order interactions. In vitro dissolution studies showed that the core-sheath composite nanofibre mats could disintegrate rapidly to release quercetin within 1 min. The study reported here provides an example of the systematic design, preparation, characterization and application of a new type of structural nanocomposite as a fast-disintegrating drug delivery system. PMID:24185912

  14. Quercetin as an Antiviral Agent Inhibits Influenza A Virus (IAV) Entry.

    PubMed

    Wu, Wenjiao; Li, Richan; Li, Xianglian; He, Jian; Jiang, Shibo; Liu, Shuwen; Yang, Jie

    2015-12-25

    Influenza A viruses (IAVs) cause seasonal pandemics and epidemics with high morbidity and mortality, which calls for effective anti-IAV agents. The glycoprotein hemagglutinin of influenza virus plays a crucial role in the initial stage of virus infection, making it a potential target for anti-influenza therapeutics development. Here we found that quercetin inhibited influenza infection with a wide spectrum of strains, including A/Puerto Rico/8/34 (H1N1), A/FM-1/47/1 (H1N1), and A/Aichi/2/68 (H3N2) with half maximal inhibitory concentration (IC50) of 7.756 ± 1.097, 6.225 ± 0.467, and 2.738 ± 1.931 μg/mL, respectively. Mechanism studies identified that quercetin showed interaction with the HA2 subunit. Moreover, quercetin could inhibit the entry of the H5N1 virus using the pseudovirus-based drug screening system. This study indicates that quercetin showing inhibitory activity in the early stage of influenza infection provides a future therapeutic option to develop effective, safe and affordable natural products for the treatment and prophylaxis of IAV infections.

  15. The effect of quercetin on the pharmacokinetics of chlorzoxazone, a CYP2E1 substrate, in healthy subjects.

    PubMed

    Bedada, Satish Kumar; Neerati, Prasad

    2017-10-05

    Previous in vitro studies have demonstrated that quercetin inhibits CYP2E1 enzyme, but there are no available data to indicate that quercetin inhibits CYP2E1 enzyme in humans. The purpose of the present study was to assess the effect of quercetin on CYP2E1 enzyme activity in healthy subjects using chlorzoxazone (CHZ) as a CYP2E1 substrate. An open-label, two-period, sequential study was conducted in 12 healthy subjects. A single dose of CHZ 250 mg was given to subjects during control phase and after treatment phases. Quercetin at a dose of 500 mg was given to subjects twice daily for a period of 10 days. The blood samples were collected at predetermined time intervals after CHZ dosing and analyzed to determine the concentrations of CHZ and 6-hydroxychlorzoxazone (6-OHCHZ). Treatment with quercetin significantly enhanced the maximum plasma concentration (C max), area under the curve (AUC), and half-life (t 1/2) by 47.8, 69.3, and 36.4%, respectively, while significantly decreased the elimination rate constant (k el) and apparent oral clearance (CL/F) of CHZ by 25.1 and 41.6%, respectively, in comparison with the control. On the other hand, C max and AUC of 6-OHCHZ were decreased by 30.1 and 32.6%, respectively, after quercetin treatment when compared to control. In addition, geometric mean ratios and 90% confidence intervals for C max and AUC of CHZ and 6-OHCHZ were both out of the no-effect boundaries of 0.80-1.25, which indicates a significant pharmacokinetic interaction present between CHZ and quercetin. Furthermore, treatment with quercetin significantly decreased the metabolic ratios of C max and AUC by 57.1 and 60.1%, respectively, as compared to control suggesting that reduced formation of CHZ to 6-OHCHZ. The results suggest that altered pharmacokinetics of CHZ might be attributed to quercetin-mediated inhibition of CYP2E1 enzyme. Further, the inhibition of CYP2E1 by quercetin may represent a novel therapeutic approach for minimizing the ethanol

  16. Chemical Proteomics Identifies Heterogeneous Nuclear Ribonucleoprotein (hnRNP) A1 as the Molecular Target of Quercetin in Its Anti-cancer Effects in PC-3 Cells*

    PubMed Central

    Ko, Chia-Chen; Chen, Yun-Ju; Chen, Chih-Ta; Liu, Yu-Chih; Cheng, Fong-Chi; Hsu, Kai-Chao; Chow, Lu-Ping

    2014-01-01

    Quercetin, a flavonoid abundantly present in plants, is widely used as a phytotherapy in prostatitis and prostate cancer. Although quercetin has been reported to have a number of therapeutic effects, the cellular target(s) responsible for its anti-cancer action has not yet been clearly elucidated. Here, employing affinity chromatography and mass spectrometry, we identified heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) as a direct target of quercetin. A specific interaction between quercetin and hnRNPA1 was validated by immunoblotting and in vitro binding experiments. We found that quercetin bound the C-terminal region of hnRNPA1, impairing the ability of hnRNPA1 to shuttle between the nucleus and cytoplasm and ultimately resulting in its cytoplasmic retention. In addition, hnRNPA1 was recruited to stress granules after treatment of cells with quercetin for up to 48 h, and the levels of cIAP1 (cellular inhibitor of apoptosis), an internal ribosome entry site translation-dependent protein, were reduced by hnRNPA1 regulation. This is the first report that anti-cancer effects of quercetin are mediated, in part, by impairing functions of hnRNPA1, insights that were obtained using a chemical proteomics strategy. PMID:24962584

  17. Chemical proteomics identifies heterogeneous nuclear ribonucleoprotein (hnRNP) A1 as the molecular target of quercetin in its anti-cancer effects in PC-3 cells.

    PubMed

    Ko, Chia-Chen; Chen, Yun-Ju; Chen, Chih-Ta; Liu, Yu-Chih; Cheng, Fong-Chi; Hsu, Kai-Chao; Chow, Lu-Ping

    2014-08-08

    Quercetin, a flavonoid abundantly present in plants, is widely used as a phytotherapy in prostatitis and prostate cancer. Although quercetin has been reported to have a number of therapeutic effects, the cellular target(s) responsible for its anti-cancer action has not yet been clearly elucidated. Here, employing affinity chromatography and mass spectrometry, we identified heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) as a direct target of quercetin. A specific interaction between quercetin and hnRNPA1 was validated by immunoblotting and in vitro binding experiments. We found that quercetin bound the C-terminal region of hnRNPA1, impairing the ability of hnRNPA1 to shuttle between the nucleus and cytoplasm and ultimately resulting in its cytoplasmic retention. In addition, hnRNPA1 was recruited to stress granules after treatment of cells with quercetin for up to 48 h, and the levels of cIAP1 (cellular inhibitor of apoptosis), an internal ribosome entry site translation-dependent protein, were reduced by hnRNPA1 regulation. This is the first report that anti-cancer effects of quercetin are mediated, in part, by impairing functions of hnRNPA1, insights that were obtained using a chemical proteomics strategy.

  18. Quercetin Treatment Ameliorates Systemic Oxidative Stress in Cirrhotic Rats

    PubMed Central

    Vieira, Emanuelle Kerber; Bona, Silvia; Di Naso, Fábio Cangeri; Porawski, Marilene; Tieppo, Juliana; Marroni, Norma Possa

    2011-01-01

    Our aim was to investigate whether the antioxidant quercetin protects against liver injury and ameliorates the systemic oxidative stress in rats with common bile duct ligation. Secondary biliary cirrhosis was induced through 28 days of bile duct obstruction. Animals received quercetin (Q) after 14 days of obstruction. Groups of control (CO) and cirrhotic (CBDL) animals received a daily 50 mg/kg body weight i.p. injection of quercetin (CO + Q; CBDL + Q) or vehicle (CO; CBDL). Quercetin corrected the reduction in superoxide dismutase (SOD), catalase CAT, and glutathione peroxidase GPx activities and prevented the increase of thiobarbituric acid reactive substances (TBARS), aminotransferases, and alkaline phosphatase in cirrhotic animals. Quercetin administration also corrected the reduced total nitrate concentration in the liver and prevented liver fibrosis and necrosis. These effects suggest that quercetin might be a useful agent to preserve liver function and prevent systemic oxidative stress. PMID:21991520

  19. Determination of quercetin glycosides and free quercetin in buckwheat by capillary micellar electrokinetic chromatography.

    PubMed

    Dadáková, Eva; Kalinová, Jana

    2010-06-01

    A simple and reliable method for determination of quercetin glycosides and free quercetin in buckwheat flower, leaves, stems and achenes was developed. The method consists of flavonoid extraction from freeze-dried homogenous material in 50% v/v methanol solution and in presence of an antioxidant, cleaning of extract and analyte isolation using SPE. Analytical step uses capillary micellar electrokinetic chromatography. The working ranges, LOD and LOQ, recovery, precision and measurement uncertainty were calculated. The method is suitable for samples from buckwheat. The highest content of rutin was found in flowers of both kinds of buckwheat (99,400 mg/kg in F. esculentum, 108,000 mg/kg in F. tataricum). The free quercetin occurs in flowers and achenes of F. esculentum, whereas flowers and achenes of F. tataricum contained quercitrin.

  20. Quercetin induces insulin secretion by direct activation of L-type calcium channels in pancreatic beta cells

    PubMed Central

    Bardy, G; Virsolvy, A; Quignard, J F; Ravier, M A; Bertrand, G; Dalle, S; Cros, G; Magous, R; Richard, S; Oiry, C

    2013-01-01

    Background and Purpose Quercetin is a natural polyphenolic flavonoid that displays anti-diabetic properties in vivo. Its mechanism of action on insulin-secreting beta cells is poorly documented. In this work, we have analysed the effects of quercetin both on insulin secretion and on the intracellular calcium concentration ([Ca2+]i) in beta cells, in the absence of any co-stimulating factor. Experimental Approach Experiments were performed on both INS-1 cell line and rat isolated pancreatic islets. Insulin release was quantified by the homogeneous time-resolved fluorescence method. Variations in [Ca2+]i were measured using the ratiometric fluorescent Ca2+ indicator Fura-2. Ca2+ channel currents were recorded with the whole-cell patch-clamp technique. Key Results Quercetin concentration-dependently increased insulin secretion and elevated [Ca2+]i. These effects were not modified by the SERCA inhibitor thapsigargin (1 μmol·L−1), but were nearly abolished by the L-type Ca2+ channel antagonist nifedipine (1 μmol·L−1). Similar to the L-type Ca2+ channel agonist Bay K 8644, quercetin enhanced the L-type Ca2+ current by shifting its voltage-dependent activation towards negative potentials, leading to the increase in [Ca2+]i and insulin secretion. The effects of quercetin were not inhibited in the presence of a maximally active concentration of Bay K 8644 (1 μmol·L−1), with the two drugs having cumulative effects on [Ca2+]i. Conclusions and Implications Taken together, our results show that quercetin stimulates insulin secretion by increasing Ca2+ influx through an interaction with L-type Ca2+ channels at a site different from that of Bay K 8644. These data contribute to a better understanding of quercetin's mechanism of action on insulin secretion. PMID:23530660

  1. Pharmacokinetics and bioavailability of quercetin glycosides in humans.

    PubMed

    Graefe, E U; Wittig, J; Mueller, S; Riethling, A K; Uehleke, B; Drewelow, B; Pforte, H; Jacobasch, G; Derendorf, H; Veit, M

    2001-05-01

    Due to its potentially beneficial impact on human health, the polyphenol quercetin has come into the focus of medicinal interest. However, data on the bioavailability of quercetin after oral intake are scarce and contradictory. Previous investigations indicate that the disposition of quercetin may depend on the sugar moiety of the glycoside or the plant matrix. To determine the influence of the sugar moiety or matrix on the absorption of quercetin, two isolated quercetin glycosides and two plant extracts were administered to 12 healthy volunteers in a four-way crossover study. Each subject received an onion supplement or quercetin-4'-O-glucoside (both equivalent to 100 mg quercetin), as well as quercetin-3-O-rutinoside and buckwheat tea (both equivalent to 200 mg quercetin). Samples were analyzed by HPLC with a 12-channel coulometric array detector. In human plasma, only quercetin glucuronides, but no free quercetin, could be detected. There was no significant difference in the bioavailability and pharmacokinetic parameters between the onion supplement and quercetin-4'-O-glucoside. Peak plasma concentrations were 2.3 +/- 1.5 microg x mL(-1) and 2.1 +/- 1.6 microg x mL(-1) (mean +/- SD) and were reached after 0.7 +/- 0.2 hours and 0.7 +/- 0.3 hours, respectively. After administration of buckwheat tea and rutin, however, peak plasma levels were--despite the higher dose-only 0.6 +/- 0.7 microg x mL(-1) and 0.3 +/- 0.3 microg x mL(-1), respectively. Peak concentrations were reached 4.3 +/- 1.8 hours after administration of buckwheat tea and 7.0 +/- 2.9 hours after ingestion of rutin. The terminal elimination half-life was about 11 hours for all treatments. Thus, the disposition of quercetin in humans primarily depends on the sugar moiety. To a minor extent, the plant matrix influences both the rate and extent of absorption in the case of buckwheat tea administration compared with the isolated compound. The site of absorption seems to be different for quercetin-4'-O

  2. Quercetin Reverses Rat Liver Preneoplastic Lesions Induced by Chemical Carcinogenesis.

    PubMed

    Carrasco-Torres, Gabriela; Monroy-Ramírez, Hugo Christian; Martínez-Guerra, Arturo Axayacatl; Baltiérrez-Hoyos, Rafael; Romero-Tlalolini, María de Los Ángeles; Villa-Treviño, Saúl; Sánchez-Chino, Xariss; Vásquez-Garzón, Verónica Rocío

    2017-01-01

    Quercetin is a flavonoid widely studied as a chemopreventive agent in different types of cancer. Previously, we reported that quercetin has a chemopreventive effect on the liver-induced preneoplastic lesions in rats. Here, we evaluated if quercetin was able not only to prevent but also to reverse rat liver preneoplastic lesions. We used the modified resistant hepatocyte model (MRHM) to evaluate this possibility. Treatment with quercetin was used 15 days after the induction of preneoplastic lesions. We found that quercetin reverses the number of preneoplastic lesions and their areas. Our results showed that quercetin downregulates the expression of EGFR and modulates this signaling pathway in spite of the activated status of EGFR as detected by the upregulation of this receptor, with respect to that observed in control rats. Besides, quercetin affects the phosphorylation status of Src-1, STAT5, and Sp-1. The better status of the liver after the treatment with quercetin could also be confirmed by the recovery in the expression of IGF-1. In conclusion, we suggest that quercetin reversed preneoplastic lesions by EGFR modulation and the activation state of Src, STAT5, and Sp1, so as the basal IGF-1.

  3. Application of Bioactive Quercetin in Oncotherapy: From Nutrition to Nanomedicine.

    PubMed

    Nam, Ju-Suk; Sharma, Ashish Ranjan; Nguyen, Lich Thi; Chakraborty, Chiranjib; Sharma, Garima; Lee, Sang-Soo

    2016-01-19

    Phytochemicals as dietary constituents are being explored for their cancer preventive properties. Quercetin is a major constituent of various dietary products and recently its anti-cancer potential has been extensively explored, revealing its anti-proliferative effect on different cancer cell lines, both in vitro and in vivo. Quercetin is known to have modulatory effects on cell apoptosis, migration and growth via various signaling pathways. Though, quercetin possesses great medicinal value, its applications as a therapeutic drug are limited. Problems like low oral bioavailability and poor aqueous solubility make quercetin an unreliable candidate for therapeutic purposes. Additionally, the rapid gastrointestinal digestion of quercetin is also a major barrier for its clinical translation. Hence, to overcome these disadvantages quercetin-based nanoformulations are being considered in recent times. Nanoformulations of quercetin have shown promising results in its uptake by the epithelial system as well as enhanced delivery to the target site. Herein we have tried to summarize various methods utilized for nanofabrication of quercetin formulations and for stable and sustained delivery of quercetin. We have also highlighted the various desirable measures for its use as a promising onco-therapeutic agent.

  4. A 12-week supplementation with quercetin does not affect natural killer cell activity, granulocyte oxidative burst activity or granulocyte phagocytosis in female human subjects.

    PubMed

    Heinz, Serena A; Henson, Dru A; Nieman, David C; Austin, Melanie D; Jin, Fuxia

    2010-09-01

    Quercetin, a flavonoid found in fruits and vegetables, is a strong antioxidant with anti-inflammatory, antimicrobial and immune-modulating properties. The purpose of the present study was to investigate the effects of long-term quercetin supplementation on innate immune function and inflammation in human subjects. Female subjects (n 120; aged 30-79 years) were recruited from the community and randomised to one of three groups, with supplements administered using double-blinded procedures: 500 mg quercetin/d (n 38), 1000 mg quercetin/d (n 40) or placebo (n 42). Subjects ingested two soft chew supplements twice daily during the 12-week study period. Fasting blood samples were obtained pre- and post-study and were analysed for plasma quercetin, IL-6, TNF-alpha and leucocyte subset cell counts. Natural killer cell activity (NKCA) and lymphocyte subsets were assessed in a subset of seventy-four subjects. Granulocyte oxidative burst activity (GOBA) and phagocytosis were assessed in sixty-four subjects. Eighteen subjects had overlapping data. Quercetin supplementation at two doses compared with placebo increased plasma quercetin (interaction effect; P < 0.001) but had no significant influence on blood leucocyte subsets, plasma IL-6 or TNF-alpha concentration, NKCA, GOBA or phagocytosis. NKCA was inversely correlated with BMI (r - 0.25; P = 0.035) and body fat percentage (r - 0.38; P = 0.001), and positively correlated with self-reported physical fitness level (r 0.24; P = 0.032). In summary, results from the present double-blinded, placebo-controlled, randomised trial indicated that quercetin supplementation at 500 and 1000 mg/d for 12 weeks significantly increased plasma quercetin levels but had no influence on measures of innate immune function or inflammation in community-dwelling adult females.

  5. Mitochondrial Dysfunction Leads to Deconjugation of Quercetin Glucuronides in Inflammatory Macrophages

    PubMed Central

    Miki, Satomi; Shiba, Yuko; Minekawa, Shoko; Nishikawa, Tomomi; Mukai, Rie; Terao, Junji; Kawai, Yoshichika

    2013-01-01

    Dietary flavonoids, such as quercetin, have long been recognized to protect blood vessels from atherogenic inflammation by yet unknown mechanisms. We have previously discovered the specific localization of quercetin-3-O-glucuronide (Q3GA), a phase II metabolite of quercetin, in macrophage cells in the human atherosclerotic lesions, but the biological significance is poorly understood. We have now demonstrated the molecular basis of the interaction between quercetin glucuronides and macrophages, leading to deconjugation of the glucuronides into the active aglycone. In vitro experiments showed that Q3GA was bound to the cell surface proteins of macrophages through anion binding and was readily deconjugated into the aglycone. It is of interest that the macrophage-mediated deconjugation of Q3GA was significantly enhanced upon inflammatory activation by lipopolysaccharide (LPS). Zymography and immunoblotting analysis revealed that β-glucuronidase is the major enzyme responsible for the deglucuronidation, whereas the secretion rate was not affected after LPS treatment. We found that extracellular acidification, which is required for the activity of β-glucuronidase, was significantly induced upon LPS treatment and was due to the increased lactate secretion associated with mitochondrial dysfunction. In addition, the β-glucuronidase secretion, which is triggered by intracellular calcium ions, was also induced by mitochondria dysfunction characterized using antimycin-A (a mitochondrial inhibitor) and siRNA-knockdown of Atg7 (an essential gene for autophagy). The deconjugated aglycone, quercetin, acts as an anti-inflammatory agent in the stimulated macrophages by inhibiting the c-Jun N-terminal kinase activation, whereas Q3GA acts only in the presence of extracellular β-glucuronidase activity. Finally, we demonstrated the deconjugation of quercetin glucuronides including the sulfoglucuronides in vivo in the spleen of mice challenged with LPS. These results showed that

  6. Silica/quercetin sol-gel hybrids as antioxidant dental implant materials

    NASA Astrophysics Data System (ADS)

    Catauro, Michelina; Papale, Ferdinando; Bollino, Flavia; Piccolella, Simona; Marciano, Sabina; Nocera, Paola; Pacifico, Severina

    2015-06-01

    The development of biomaterials with intrinsic antioxidant properties could represent a valuable strategy for preventing the onset of peri-implant diseases. In this context, quercetin, a naturally occurring flavonoid, has been entrapped at different weight percentages in a silica-based inorganic material by a sol-gel route. The establishment of hydrogen bond interactions between the flavonol and the solid matrix was ascertained by Fourier transform infrared spectroscopy. This technique also evidenced changes in the stretching frequencies of the quercetin dienonic moiety, suggesting that the formation of a secondary product occurs. Scanning electron microscopy was applied to detect the morphology of the synthesized materials. Their bioactivity was shown by the formation of a hydroxyapatite layer on sample surface soaked in a fluid that simulates the composition of human blood plasma. When the potential release of flavonol was determined by liquid chromatography coupled with ultraviolet and electrospray ionization tandem mass spectrometry techniques, the eluates displayed a retention time that was 0.5 min less than quercetin. Collision-activated dissociation mass spectrometry and untraviolet-visible spectroscopy were in accordance with the release of a quercetin derivative. The antiradical properties of the investigated systems were evaluated by DPPH and ABTS methods, whereas the 2,7-dichlorofluorescein diacetate assay highlighted their ability to inhibit the H2O2-induced intracellular production of reactive oxygen species in NIH-3T3 mouse fibroblast cells. Data obtained, along with data gathered from the MTT cytotoxicity test, revealed that the materials that entrapped the highest amount of quercetin showed notable antioxidant effectiveness.

  7. Silica/quercetin sol–gel hybrids as antioxidant dental implant materials

    PubMed Central

    Catauro, Michelina; Papale, Ferdinando; Bollino, Flavia; Piccolella, Simona; Marciano, Sabina; Nocera, Paola; Pacifico, Severina

    2015-01-01

    The development of biomaterials with intrinsic antioxidant properties could represent a valuable strategy for preventing the onset of peri-implant diseases. In this context, quercetin, a naturally occurring flavonoid, has been entrapped at different weight percentages in a silica-based inorganic material by a sol–gel route. The establishment of hydrogen bond interactions between the flavonol and the solid matrix was ascertained by Fourier transform infrared spectroscopy. This technique also evidenced changes in the stretching frequencies of the quercetin dienonic moiety, suggesting that the formation of a secondary product occurs. Scanning electron microscopy was applied to detect the morphology of the synthesized materials. Their bioactivity was shown by the formation of a hydroxyapatite layer on sample surface soaked in a fluid that simulates the composition of human blood plasma. When the potential release of flavonol was determined by liquid chromatography coupled with ultraviolet and electrospray ionization tandem mass spectrometry techniques, the eluates displayed a retention time that was 0.5 min less than quercetin. Collision-activated dissociation mass spectrometry and untraviolet-visible spectroscopy were in accordance with the release of a quercetin derivative. The antiradical properties of the investigated systems were evaluated by DPPH and ABTS methods, whereas the 2,7-dichlorofluorescein diacetate assay highlighted their ability to inhibit the H2O2-induced intracellular production of reactive oxygen species in NIH-3T3 mouse fibroblast cells. Data obtained, along with data gathered from the MTT cytotoxicity test, revealed that the materials that entrapped the highest amount of quercetin showed notable antioxidant effectiveness. PMID:27877802

  8. Is quercetin an alternative natural crosslinking agent to genipin for long-term dermal scaffolds implantation?

    PubMed

    Greco, Karin V; Francis, Lydia; Huang, Honglei; Ploeg, Rutger; Boccaccini, Aldo R; Ansari, Tahera

    2016-10-07

    As biocompatible matrices, porcine dermal scaffolds have limited application in tissue engineering due to rapid degradation following implantation. This study compared the physical, chemical and biomechanical changes that occurred when genipin and quercetin were used to crosslink dermal scaffolds and to determine whether quercetin could be used as an alternative to genipin. Physicochemical changes in the collagen were assessed using spectroscopic methods [X-ray diffraction analysis (XRD) and nuclear magnetic resonance (NMR) analysis]. The crosslinking reaction was evaluated by quantification of amino acids and the degree of this reaction by ninhydrin assay. Because the mechanical behaviour of the collagen matrices is highly influenced by crosslinking, the tensile strength of both sets of scaffolds was evaluated. The highest mechanical strength, stiffness, degree of crosslinking and changes in the packing features of collagen (measured by XRD) were achieved using genipin. Some of the results found in the quercetin-crosslinked scaffolds were possibly due to hydration and dehydration effects elicited by the solvents (phosphate-buffered saline or ethanol), as seen in the NMR results. In the quercetin-ethanol-crosslinked scaffolds, possible reorientation of the amino groups of the collagen molecule may have taken place. Therefore, depending on their proximity to the crosslinking reagent, different types and numbers of interactions may have occurred, inducing a higher crosslinking degree (as evidenced by the ninhydrin assay) and reduction in the free amino acids after reaction. Both crosslinking agents and solvents interfere in the physicochemical properties of collagen thereby inducing variations in the matrix structure. Quercetin-crosslinked scaffolds may have broader clinical application where a lower degree of crosslinking and stiffness is required. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  9. Evaluation of inhibitory effects of caffeic acid and quercetin on human liver cytochrome p450 activities.

    PubMed

    Rastogi, Himanshu; Jana, Snehasis

    2014-12-01

    When herbal drugs and conventional allopathic drugs are used together, they can interact in our body which can lead to the potential for herb-drug interactions. This work was conducted to evaluate the herb-drug interaction potential of caffeic acid and quercetin mediated by cytochrome P450 (CYP) inhibition. Human liver microsomes (HLMs) were added to each selective probe substrates of cytochrome P450 enzymes with or without of caffeic acid and quercetin. IC50 , Ki values, and the types of inhibition were determined. Both caffeic acid and quercetin were potent competitive inhibitors of CYP1A2 (Ki = 1.16 and 0.93 μM, respectively) and CYP2C9 (Ki = 0.95 and 1.67 μM, respectively). Caffeic acid was a potent competitive inhibitor of CYP2D6 (Ki = 1.10 μM) and a weak inhibitor of CYP2C19 and CYP3A4 (IC50  > 100 μM). Quercetin was a potent competitive inhibitor of CYP 2C19 and CYP3A4 (Ki = 1.74 and 4.12 μM, respectively) and a moderate competitive inhibitor of CYP2D6 (Ki = 18.72 μM). These findings might be helpful for safe and effective use of polyphenols in clinical practice. Our data indicated that it is necessary to study the in vivo interactions between drugs and pharmaceuticals with dietary polyphenols. Copyright © 2014 John Wiley & Sons, Ltd.

  10. The reversibility of the glutathionyl-quercetin adduct spreads oxidized quercetin-induced toxicity

    SciTech Connect

    Boots, Agnes W. . E-mail: a.boots@farmaco.unimaas.nl; Balk, Jiska M.; Bast, Aalt; Haenen, Guido R.M.M.

    2005-12-16

    Quercetin is one of the most prominent dietary antioxidants. During its antioxidant activity, quercetin becomes oxidized into its o-quinone/quinone methide QQ. QQ is toxic since it instantaneously reacts with thiols of, e.g., proteins. In cells, QQ will initially form an adduct with glutathione (GSH), giving GSQ. We have found that GSQ is not stable; it dissociates continuously into GSH and QQ with a half life of 2 min. Surprisingly, GSQ incubated with 2-mercapto-ethanol (MSH), a far less reactive thiol, results in the conversion of GSQ into the MSH-adduct MSQ. A similar conversion of GSQ into relatively stable protein thiol-quercetin adducts is expected. With the dithiol dihydrolipoic acid (L(SH){sub 2}), quercetin is formed out of GSQ. These results indicate that GSQ acts as transport and storage of QQ. In that way, the initially highly focussed toxicity of QQ is dispersed by the formation of GSQ that finally spreads QQ-induced toxicity, probably even over cells.

  11. Quercetin inhibits rhinovirus replication in vitro and in vivo

    PubMed Central

    Ganesan, Shyamala; Faris, Andrea N.; Comstock, Adam T.; Wang, Qiong; Nanua, Suparna; Hershenson, Marc B.; Sajjan, Uma S.

    2012-01-01

    Summary Rhinovirus (RV), which is responsible for the majority of common colds, also causes exacerbations in patients with asthma and chronic obstructive pulmonary disease. So far, there are no drugs available for treatment of rhinovirus infection. We examined the effect of quercetin, a plant flavanol on RV infection in vitro and in vivo. Pretreatment of airway epithelial cells with quercetin decreased Akt phosphosphorylation, viral endocytosis and IL-8 responses. Addition of quercetin 6 h after RV infection (after viral endocytosis) reduced viral load, IL-8 and IFN responses in airway epithelial cells. This was associated with decreased levels of negative and positive strand viral RNA, and RV capsid protein, abrogation of RV-induced eIF4GI cleavage and increased phosphorylation of eIF2α. In mice infected with RV, quercetin treatment decreased viral replication as well as expression of chemokines and cytokines. Quercetin treatment also attenuated RV-induced airway cholinergic hyperresponsiveness. Together, our results suggest that quercetin inhibits RV endocytosis and replication in airway epithelial cells at multiple stages of the RV life cycle. Quercetin also decreases expression of pro-inflammatory cytokines and improves lung function in RV-infected mice. Based on these observations, further studies examining the potential benefits of quercetin in the prevention and treatment of RV infection are warranted. PMID:22465313

  12. Quercetin Reduces Ehrlich Tumor-Induced Cancer Pain in Mice

    PubMed Central

    Calixto-Campos, Cassia; Corrêa, Mab P.; Carvalho, Thacyana T.; Zarpelon, Ana C.; Hohmann, Miriam S. N.; Rossaneis, Ana C.; Coelho-Silva, Leticia; Pavanelli, Wander R.; Pinge-Filho, Phileno; Bernardy, Catia C. F.; Verri, Waldiceu A.

    2015-01-01

    Cancer pain directly affects the patient's quality of life. We have previously demonstrated that the subcutaneous administration of the mammary adenocarcinoma known as Ehrlich tumor induces pain in mice. Several studies have shown that the flavonoid quercetin presents important biological effects, including anti-inflammatory, antioxidant, analgesic, and antitumor activity. Therefore, the analgesic effect and mechanisms of quercetin were evaluated in Ehrlich tumor-induced cancer pain in mice. Intraperitoneal (i.p.) treatments with quercetin reduced Ehrlich tumor-induced mechanical and thermal hyperalgesia, but not paw thickness or histological alterations, indicating an analgesic effect without affecting tumor growth. Regarding the analgesic mechanisms of quercetin, it inhibited the production of hyperalgesic cytokines IL-1β and TNFα and decreased neutrophil recruitment (myeloperoxidase activity) and oxidative stress. Naloxone (opioid receptor antagonist) inhibited quercetin analgesia without interfering with neutrophil recruitment, cytokine production, and oxidative stress. Importantly, cotreatment with morphine and quercetin at doses that were ineffective as single treatment reduced the nociceptive responses. Concluding, quercetin reduces the Ehrlich tumor-induced cancer pain by reducing the production of hyperalgesic cytokines, neutrophil recruitment, and oxidative stress as well as by activating an opioid-dependent analgesic pathway and potentiation of morphine analgesia. Thus, quercetin treatment seems a suitable therapeutic approach for cancer pain that merits further investigation. PMID:26351625

  13. Quercetin reduces Ehrlich tumor-induced cancer pain in mice.

    PubMed

    Calixto-Campos, Cassia; Corrêa, Mab P; Carvalho, Thacyana T; Zarpelon, Ana C; Hohmann, Miriam S N; Rossaneis, Ana C; Coelho-Silva, Leticia; Pavanelli, Wander R; Pinge-Filho, Phileno; Crespigio, Jefferson; Bernardy, Catia C F; Casagrande, Rubia; Verri, Waldiceu A

    2015-01-01

    Cancer pain directly affects the patient's quality of life. We have previously demonstrated that the subcutaneous administration of the mammary adenocarcinoma known as Ehrlich tumor induces pain in mice. Several studies have shown that the flavonoid quercetin presents important biological effects, including anti-inflammatory, antioxidant, analgesic, and antitumor activity. Therefore, the analgesic effect and mechanisms of quercetin were evaluated in Ehrlich tumor-induced cancer pain in mice. Intraperitoneal (i.p.) treatments with quercetin reduced Ehrlich tumor-induced mechanical and thermal hyperalgesia, but not paw thickness or histological alterations, indicating an analgesic effect without affecting tumor growth. Regarding the analgesic mechanisms of quercetin, it inhibited the production of hyperalgesic cytokines IL-1β and TNFα and decreased neutrophil recruitment (myeloperoxidase activity) and oxidative stress. Naloxone (opioid receptor antagonist) inhibited quercetin analgesia without interfering with neutrophil recruitment, cytokine production, and oxidative stress. Importantly, cotreatment with morphine and quercetin at doses that were ineffective as single treatment reduced the nociceptive responses. Concluding, quercetin reduces the Ehrlich tumor-induced cancer pain by reducing the production of hyperalgesic cytokines, neutrophil recruitment, and oxidative stress as well as by activating an opioid-dependent analgesic pathway and potentiation of morphine analgesia. Thus, quercetin treatment seems a suitable therapeutic approach for cancer pain that merits further investigation.

  14. Kaempferol and quercetin glycosides from Rubus idaeus L. leaves.

    PubMed

    Gudej, Jan

    2003-01-01

    Quercetin 3-0-beta-D-glucoside (I), quercetin and kaempferol 3-0-beta-D-galactosides (II, III), kaempferol 3-0-beta-L-arabinopyranoside (IV), kaempferol 3-0-beta-D-(6''-E-p-coumaroyl)-glucoside (tiliroside) (V) and methyl gallate (VI) were isolated from Rubus idaeus L. subspecies culture of Norna leaves and fully characterized.

  15. Quercetin protection against ciprofloxacin induced liver damage in rats.

    PubMed

    Taslidere, E; Dogan, Z; Elbe, H; Vardi, N; Cetin, A; Turkoz, Y

    2016-01-01

    Ciprofloxacin is a common, broad spectrum antibacterial agent; however, evidence is accumulating that ciprofloxacin may cause liver damage. Quercetin is a free radical scavenger and antioxidant. We investigated histological changes in hepatic tissue of rats caused by ciprofloxacin and the effects of quercetin on these changes using histochemical and biochemical methods. We divided 28 adult female Wistar albino rats into four equal groups: control, quercetin treated, ciprofloxacin treated, and ciprofloxacin + quercetin treated. At the end of the experiment, liver samples were processed for light microscopic examination and biochemical measurements. Sections were prepared and stained with hematoxylin and eosin, and a histopathologic damage score was calculated. The sections from the control group appeared normal. Hemorrhage, inflammatory cell infiltration and intracellular vacuolization were observed in the ciprofloxacin group. The histopathological findings were reduced in the group treated with quercetin. Significant differences were found between the control and ciprofloxacin groups, and between the ciprofloxacin and ciprofloxacin + quercetin groups. Quercetin administration reduced liver injury caused by ciprofloxacin in rats. We suggest that quercetin may be useful for preventing ciprofloxacin induced liver damage.

  16. Evaluation of quercetin as a potential drug in osteosarcoma treatment.

    PubMed

    Berndt, Kersten; Campanile, Carmen; Muff, Roman; Strehler, Emanuel; Born, Walter; Fuchs, Bruno

    2013-04-01

    Osteosarcoma is the most common malignant bone tumor in children and young adults. Since the introduction of chemotherapy, the 5-year survival rate of patients with non-metastatic osteosarcoma is ~70%. The main problems in osteosarcoma therapy are the occurrence of metastases, severe side-effects and chemoresistance. Antiproliferative and apoptotic effects of quercetin were shown in several types of cancers, including breast cancer and lung carcinoma. The present study investigates the cytotoxic potential of quercetin, a dietary flavonoid, in a highly metastasizing human osteosarcoma cell line, 143B. We found that quercetin induces growth inhibition, G2/M phase arrest, and apoptosis in the 143B osteosarcoma cell line. We also observed impaired adhesion and migratory potential after the addition of quercetin. Since quercetin has already been shown to have low side effects in a clinical phase I trial in advanced cancer patients, this compound may have considerable potential for osteosarcoma treatment.

  17. Quercetin attenuates doxorubicin cardiotoxicity by modulating Bmi-1 expression

    PubMed Central

    Dong, Qinghua; Chen, Long; Lu, Qunwei; Sharma, Sherven; Li, Lei; Morimoto, Sachio; Wang, Guanyu

    2014-01-01

    Background and Purpose Doxorubicin-based chemotherapy induces cardiotoxicity, which limits its clinical application. We previously reported the protective effects of quercetin against doxorubicin-induced hepatotoxicity. In this study, we tested the effects of quercetin on the expression of Bmi-1, a protein regulating mitochondrial function and ROS generation, as a mechanism underlying quercetin-mediated protection against doxorubicin-induced cardiotoxicity. Experimental Approach Effects of quercetin on doxorubicin-induced cardiotoxicity was evaluated using H9c2 cardiomyocytes and C57BL/6 mice. Changes in apoptosis, mitochondrial function, oxidative stress and related signalling were evaluated in H9c2 cells. Cardiac function, serum enzyme activity and reactive oxygen species (ROS) generation were measured in mice after a single injection of doxorubicin with or without quercetin pre-treatment. Key Results In H9c2 cells, quercetin reduced doxorubicin-induced apoptosis, mitochondrial dysfunction, ROS generation and DNA double-strand breaks. The quercetin-mediated protection against doxorubicin toxicity was characterized by decreased expression of Bid, p53 and oxidase (p47 and Nox1) and by increased expression of Bcl-2 and Bmi-1. Bmi-1 siRNA abolished the protective effect of quercetin against doxorubicin-induced toxicity in H9c2 cells. Furthermore, quercetin protected mice from doxorubicin-induced cardiac dysfunction that was accompanied by reduced ROS levels and lipid peroxidation, but enhanced the expression of Bmi-1 and anti-oxidative superoxide dismutase. Conclusions and Implications Our results demonstrate that quercetin decreased doxorubicin-induced cardiotoxicity in vitro and in vivo by reducing oxidative stress by up-regulation of Bmi-1 expression. The findings presented in this study have potential applications in preventing doxorubicin-induced cardiomyopathy. PMID:24902966

  18. Quercetin attenuates doxorubicin cardiotoxicity by modulating Bmi-1 expression.

    PubMed

    Dong, Qinghua; Chen, Long; Lu, Qunwei; Sharma, Sherven; Li, Lei; Morimoto, Sachio; Wang, Guanyu

    2014-10-01

    Doxorubicin-based chemotherapy induces cardiotoxicity, which limits its clinical application. We previously reported the protective effects of quercetin against doxorubicin-induced hepatotoxicity. In this study, we tested the effects of quercetin on the expression of Bmi-1, a protein regulating mitochondrial function and ROS generation, as a mechanism underlying quercetin-mediated protection against doxorubicin-induced cardiotoxicity. Effects of quercetin on doxorubicin-induced cardiotoxicity was evaluated using H9c2 cardiomyocytes and C57BL/6 mice. Changes in apoptosis, mitochondrial function, oxidative stress and related signalling were evaluated in H9c2 cells. Cardiac function, serum enzyme activity and reactive oxygen species (ROS) generation were measured in mice after a single injection of doxorubicin with or without quercetin pre-treatment. In H9c2 cells, quercetin reduced doxorubicin-induced apoptosis, mitochondrial dysfunction, ROS generation and DNA double-strand breaks. The quercetin-mediated protection against doxorubicin toxicity was characterized by decreased expression of Bid, p53 and oxidase (p47 and Nox1) and by increased expression of Bcl-2 and Bmi-1. Bmi-1 siRNA abolished the protective effect of quercetin against doxorubicin-induced toxicity in H9c2 cells. Furthermore, quercetin protected mice from doxorubicin-induced cardiac dysfunction that was accompanied by reduced ROS levels and lipid peroxidation, but enhanced the expression of Bmi-1 and anti-oxidative superoxide dismutase. Our results demonstrate that quercetin decreased doxorubicin-induced cardiotoxicity in vitro and in vivo by reducing oxidative stress by up-regulation of Bmi-1 expression. The findings presented in this study have potential applications in preventing doxorubicin-induced cardiomyopathy. © 2014 The British Pharmacological Society.

  19. Comparative Effect of Quercetin and Quercetin-3-O-β-d-Glucoside on Fibrin Polymers, Blood Clots, and in Rodent Models.

    PubMed

    Choi, Jun-Hui; Kim, Kyung-Je; Kim, Seung

    2016-11-01

    The present study evaluates the in vitro, in vivo, and ex vivo antithrombotic and anticoagulant effect of two flavonoids: quercetin and quercetin-3-O-β-d-glucoside (isoquercetin). The present results have shown that quercetin and isoquercetin inhibit the enzymatic activity of thrombin and FXa and suppress fibrin clot formation and blood clotting. The prolongation effect of quercetin and isoquercetin against epinephrine and collagen-induced platelet activation may have been caused by intervention in intracellular signaling pathways including coagulation cascade and aggregation response on platelets and blood. The in vivo and ex vivo anticoagulant efficacy of quercetin and isoquercetin was evaluated in thrombin-induced acute thromboembolism model and in ICR mice. Our findings showed that in vitro and in vivo inhibitory effects of quercetin were slightly higher than that of quercetin glucoside, whereas in vitro and ex vivo anticoagulant effects of quercetin were weaker than that of quercetin glucoside because of their structural characteristics.

  20. Quercetin induces apoptosis and autophagy in primary effusion lymphoma cells by inhibiting PI3K/AKT/mTOR and STAT3 signaling pathways.

    PubMed

    Granato, Marisa; Rizzello, Celeste; Gilardini Montani, Maria Saveria; Cuomo, Laura; Vitillo, Marina; Santarelli, Roberta; Gonnella, Roberta; D'Orazi, Gabriella; Faggioni, Alberto; Cirone, Mara

    2017-03-01

    Quercetin, a bioflavonoid contained in several vegetables daily consumed, has been studied for long time for its antiinflammatory and anticancer properties. Quercetin interacts with multiple cancer-related pathways such as PI3K/AKT, Wnt/β-catenin and STAT3. These pathways are hyperactivated in primary effusion lymphoma (PEL), an aggressive B cell lymphoma whose pathogenesis is strictly linked to the oncogenic virus Kaposis' Sarcoma-associated Herpesvirus (KSHV). In this study, we found that quercetin inhibited PI3K/AKT/mTOR and STAT3 pathways in PEL cells, and as a consequence, it down-regulated the expression of the prosurvival cellular proteins such as c-FLIP, cyclin D1 and cMyc. It also reduced the release of IL-6 and IL-10 cytokines, leading to PEL cell death. Moreover, quercetin induced a prosurvival autophagy in these cells and increased the cytotoxic effect of bortezomib, a proteasomal inhibitor, against them. Interestingly, quercetin decreased also the expression of latent and lytic KSHV proteins involved in PEL tumorigenesis and up-regulated the surface expression of HLA-DR and calreticulin, rendering the dying cells more likely detectable by the immune system. The results obtained in this study indicate that quercetin, which does not exert any cytotoxicity against normal B cells, may represent a good candidate for the treatment of this aggressive B cell lymphoma, especially in combination with autophagy inhibitors or with bortezomib. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. On the causes and consequences of the uncoupler-like effects of quercetin and dehydrosilybin in H9c2 cells.

    PubMed

    Zholobenko, Aleksey V; Mouithys-Mickalad, Ange; Dostal, Zdenek; Serteyn, Didier; Modriansky, Martin

    2017-01-01

    Quercetin and dehydrosilybin are polyphenols which are known to behave like uncouplers of respiration in isolated mitochondria. Here we investigated whether the effect is conserved in whole cells. Following short term incubation, neither compound uncouples mitochondrial respiration in whole H9c2 cells below 50μM. However, following hypoxia, or long term incubation, leak (state IV with oligomycin) oxygen consumption is increased by quercetin. Both compounds partially protected complex I respiration, but not complex II in H9c2 cells following hypoxia. In a permeabilised H9c2 cell model, the increase in leak respiration caused by quercetin is lowered by increased [ADP] and is increased by adenine nucleotide transporter inhibitor, atractyloside, but not bongkrekic acid. Both quercetin and dehydrosilybin dissipate mitochondrial membrane potential in whole cells. In the case of quercetin, the effect is potentiated post hypoxia. Genetically encoded Ca++ sensors, targeted to the mitochondria, enabled the use of fluorescence microscopy to show that quercetin decreased mitochondrial [Ca++] while dehydrosilybin did not. Likewise, quercetin decreases accumulation of [Ca++] in mitochondria following hypoxia. Fluorescent probes were used to show that both compounds decrease plasma membrane potential and increase cytosolic [Ca++]. We conclude that the uncoupler-like effects of these polyphenols are attenuated in whole cells compared to isolated mitochondria, but downstream effects are nevertheless apparent. Results suggest that the effect of quercetin observed in whole and permeabilised cells may originate in the mitochondria, while the mechanism of action of cardioprotection by dehydrosilybin may be less dependent on mitochondrial uncoupling than originally thought. Rather, protective effects may originate due to interactions at the plasma membrane.

  2. Quercetin protects against atherosclerosis by inhibiting dendritic cell activation.

    PubMed

    Lin, Weiqun; Wang, Wenting; Wang, Dongliang; Ling, Wenhua

    2017-09-01

    Quercetin is a typical flavonol with atheroprotective effects, but the effect of quercetin on dendritic cell (DC) maturation in relation to atherosclerosis has not yet been clearly defined. Thus, we investigated whether quercetin can inhibit DC maturation and evaluated its potential value in atherosclerosis progression in ApoE(-/-) mice. Quercetin consumption inhibited DC activation, inflammatory response and suppressed the progression of atherosclerosis in ApoE(-/-) mice. Subsequently, quercetin treatment inhibited the phenotypic and functional maturation of DCs, as evidenced not only by downregulation of CD80, CD86, MHC-II, IL-6 and IL-12 but also by a reduction in the ability to stimulate T cell allogeneic proliferation. Finally, an in vitro study demonstrated that quercetin inhibited DC maturation via upregulation of Dabs, which then downregulated the Src/PI3K/Akt-NF-κB-inflammatory pathways. Our data indicate that quercetin attenuates atherosclerosis progression by regulating DC activation via Dab2 protein expression. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Enhancing oral bioavailability of quercetin using novel soluplus polymeric micelles

    NASA Astrophysics Data System (ADS)

    Dian, Linghui; Yu, Enjiang; Chen, Xiaona; Wen, Xinguo; Zhang, Zhengzan; Qin, Lingzhen; Wang, Qingqing; Li, Ge; Wu, Chuanbin

    2014-12-01

    To improve its poor aqueous solubility and stability, the potential chemotherapeutic drug quercetin was encapsulated in soluplus polymeric micelles by a modified film dispersion method. With the encapsulation efficiency over 90%, the quercetin-loaded polymeric micelles (Qu-PMs) with drug loading of 6.7% had a narrow size distribution around mean size of 79.00 ± 2.24 nm, suggesting the complete dispersibility of quercetin in water. X-ray diffraction (XRD) patterns illustrated that quercetin was in amorphous or molecular form within PMs. Fourier transform infrared spectroscopy (FTIR) indicated that quercetin formed intermolecular hydrogen bonding with carriers. An in vitro dialysis test showed the Qu-PMs possessed significant sustained-release property, and the formulation was stable for at least 6 months under accelerated conditions. The pharmacokinetic study in beagle dogs showed that absorption of quercetin after oral administration of Qu-PMs was improved significantly, with a half-life 2.19-fold longer and a relative oral bioavailability of 286% as compared to free quercetin. Therefore, these novel soluplus polymeric micelles can be applied to encapsulate various poorly water-soluble drugs towards a development of more applicable therapeutic formulations.

  4. Antioxidative and antiinflammatory activities of quercetin-loaded silica nanoparticles.

    PubMed

    Lee, Ga Hyun; Lee, Sung June; Jeong, Sang Won; Kim, Hyun-Chul; Park, Ga Young; Lee, Se Geun; Choi, Jin Hyun

    2016-07-01

    Utilizing the biological activities of compounds by encapsulating natural components in stable nanoparticles is an important strategy for a variety of biomedical and healthcare applications. In this study, quercetin-loaded silica nanoparticles were synthesized using an oil-in-water microemulsion method, which is a suitable system for producing functional nanoparticles of controlled size and shape. The resulting quercetin-loaded silica nanoparticles were spherical, highly monodispersed, and stable in an aqueous system. Superoxide radical scavenging effects were found for the quercetin-loaded silica nanoparticles as well as free quercetin. The quercetin-loaded silica nanoparticles showed cell viability comparable to that of the controls. The amounts of proinflammatory cytokines produced by macrophages, such as interleukin 1 beta, interleukin 6, and tumor necrosis factor alpha, were reduced significantly for the quercetin-loaded silica nanoparticles. These results suggest that the antioxidative and antiinflammatory activities of quercetin are maintained after encapsulation in silica. Silica nanoparticles can be used for the effective and stable incorporation of biologically active natural components into composite biomaterials.

  5. Comparison of the bioavailability of quercetin and catechin in rats.

    PubMed

    Manach, C; Texier, O; Morand, C; Crespy, V; Régérat, F; Demigné, C; Rémésy, C

    1999-12-01

    Quercetin and catechin are present in noticeable amounts in human diet and these polyphenolic compounds are supposed to exert beneficial effects on human health. However, their metabolic fates in the organism have never been compared. In the present study, rats were fed a 0.25% quercetin or a 0.25% catechin diet. Quercetin and catechin metabolites were analyzed in plasma and liver samples by high-performance liquid chromatography coupled to an ultraviolet or a multielectrode coulometric detection. All plasma metabolites were present as conjugated forms, but catechin metabolites were mainly constituted by glucuronidated derivatives, whereas quercetin metabolites were sulfo- and glucurono-sulfo conjugates. Quercetin was more intensively methylated than catechin in plasma. The plasma quercetin metabolites are well maintained during the postabsorptive period (approximately 50 microM), whereas the concentration of catechin metabolites dropped dramatically between 12- and 24-h after an experimental meal (from 38.0 to 4.5 microM). In the liver, the concentrations of quercetin and catechin derivatives were lower than in plasma, and no accumulation was observed when the rats were adapted for 14 d to the supplemented diets. The hepatic metabolites were intensively methylated (90-95%), but in contrast to plasma, some free aglycones could be detected. Thus, it clearly appears that studies dealing with the biological impact of these polyphenols should take into account the feature of their bioavailability, particularly the fact that their circulating metabolites are conjugated derivatives.

  6. Quercetin Attenuates Lactate Production and Extracellular Matrix Secretion in Keratoconus

    PubMed Central

    McKay, T. B.; Lyon, D.; Sarker-Nag, A.; Priyadarsini, S.; Asara, J. M.; Karamichos, D.

    2015-01-01

    Keratoconus(KC) is an ecstatic corneal disease leading to corneal-thinning and the formation of a cone-like cornea. Elevated lactate levels, increased oxidative stress, and myofibroblast formation have all been previously reported. In the current study, we assess the role of Quercetin on collagen secretion and myofibroblast formation in KC in vitro. Human corneal fibroblasts(HCFs) and human keratoconus cells(HKCs) were treated with a stable Vitamin C derivative and cultured for 4 weeks, stimulating formation of a self-assembled extracellular matrix. All samples were analyzed using Western blots and targeted tandem mass spectrometry. Our data showed that Quercetin significantly down regulates myofibroblast differentiation and fibrotic markers, such as α-smooth muscle actin (α-SMA) and Collagen III (Col III), in both HCFs and HKCs. Collagen III secretion was reduced 80% in both HCFs and HKCs following Quercetin treatment. Furthermore, Quercetin reduced lactate production by HKCs to normal HCF levels. Quercetin down regulated TGF-βR2 and TGF-β2 expression in HKCs suggesting a significant link to the TGF-β pathway. These results assert that Quercetin is a key regulator of fibrotic markers and ECM assembly by modulating cellular metabolism and TGF-β signaling. Our study suggests that Quercetin is a potential therapeutic for treatment of corneal dystrophies, such as KC. PMID:25758533

  7. Chemotherapeutic potential of quercetin on human bladder cancer cells.

    PubMed

    Oršolić, Nada; Karač, Ivo; Sirovina, Damir; Kukolj, Marina; Kunštić, Martina; Gajski, Goran; Garaj-Vrhovac, Vera; Štajcar, Damir

    2016-07-28

    In an effort to improve local bladder cancer control, we investigated the cytotoxic and genotoxic effects of quercetin on human bladder cancer T24 cells. The cytotoxic effect of quercetin against T24 cells was examined by MTT test, clonogenic assay as well as DNA damaging effect by comet assay. In addition, the cytotoxic effect of quercetin on the primary culture of papillary urothelial carcinoma (PUC), histopathological stage T1 of low- or high-grade tumours, was investigated. Our analysis demonstrated a high correlation between reduced number of colony and cell viability and an increase in DNA damage of T24 cells incubated with quercetin at doses of 1 and 50 µM during short term incubation (2 h). At all exposure times (24, 48 and 72 h), the efficacy of quercetin, administered at a 10× higher dose compared to T24 cells, was statistically significant (P < 0.05) for the primary culture of PUC. In conclusion, our study suggests that quercetin could inhibit cell proliferation and colony formation of human bladder cancer cells by inducing DNA damage and that quercetin may be an effective chemopreventive and chemotherapeutic agent for papillary urothelial bladder cancer after transurethral resection.

  8. Quercetin accumulation by chronic administration causes the caspase-3 activation in liver and brain of mice.

    PubMed

    Choi, Eun Jeong; Kim, Gun-Hee

    2010-01-01

    Quercetin is an excellent antioxidant that has a variety of side effects. This study investigated whether the chronic administration of quercetin in mice induces apoptosis. Mice were divided randomly into three treatment groups. Quercetin was administered orally to two of three groups at 100 and 250 mg/kg body weight (BW) for 18 days. The serum quercetin level increased in a dose-dependent manner, although the quercetin levels in the liver and brain were lower than in serum. Nevertheless, quercetin induced apoptosis in both the liver and brain, as evidenced by increased caspase-3 expression and activity. Quercetin-induced apoptosis seems to be associated with quercetin accumulation. Moreover, with quercetin accumulation, the brain was more susceptible to apoptosis than the liver. In conclusion, quercetin administration at a high dose may lead to apoptosis in the liver and brain of mouse.

  9. Proatherogenic macrophage activities are targeted by the flavonoid quercetin.

    PubMed

    Lara-Guzman, Oscar J; Tabares-Guevara, Jorge H; Leon-Varela, Yudy M; Álvarez, Rafael M; Roldan, Miguel; Sierra, Jelver A; Londoño-Londoño, Julian A; Ramirez-Pineda, Jose R

    2012-11-01

    Many studies have demonstrated that the flavonoid quercetin protects against cardiovascular disease (CVD) and related risk factors. Atherosclerosis, the underlying cause of CVD, is also attenuated by oral quercetin administration in animal models. Although macrophages are key players during fatty streak formation and plaque progression and aggravation, little is known about the effects of quercetin on atherogenic macrophages. Here, we report that primary bone marrow-derived macrophages internalized less oxidized low-density lipoprotein (oxLDL) and accumulated less intracellular cholesterol in the presence of quercetin. This reduction of foam cell formation correlated with reduced surface expression of the oxLDL receptor CD36. Quercetin also targeted the lipopolysaccharide-dependent, oxLDL-independent pathway of lipid droplet formation in macrophages. In oxLDL-stimulated macrophages, quercetin inhibited reactive oxygen species production and interleukin (IL)-6 secretion. In a system that evaluated cholesterol crystal-induced IL-1β secretion via nucleotide-binding domain and leucine-rich repeat containing protein 3 inflammasome activation, quercetin also exhibited an inhibitory effect. Dyslipidemic apolipoprotein E-deficient mice chronically treated with intraperitoneal quercetin injections had smaller atheromatous lesions, reduced lipid deposition, and less macrophage and T cell inflammatory infiltrate in the aortic roots than vehicle-treated animals. Serum levels of total cholesterol and the lipid peroxidation product malondialdehyde were also reduced in these mice. Our results demonstrate that quercetin interferes with both key proatherogenic activities of macrophages, namely foam cell formation and pro-oxidant/proinflammatory responses, and these effects may explain the atheroprotective properties of this common flavonoid.

  10. Role of Quercetin in Modulating Chloride Transport in the Intestine

    PubMed Central

    Yu, Bo; Jiang, Yu; Jin, Lingling; Ma, Tonghui; Yang, Hong

    2016-01-01

    Epithelial chloride channels provide the pathways for fluid secretion in the intestine. Cystic fibrosis transmembrane conductance regulator (CFTR) and calcium-activated chloride channels (CaCCs) are the main chloride channels in the luminal membrane of enterocytes. These transmembrane proteins play important roles in many physiological processes. In this study, we have identified a flavonoid quercetin as a modulator of CaCC chloride channel activity. Fluorescence quenching assay showed that quercetin activated Cl− transport in a dose-dependent manner, with EC50 ~37 μM. Short-circuit current analysis confirmed that quercetin activated CaCC-mediated Cl− currents in HT-29 cells that can be abolished by CaCCinh-A01. Ex vivo studies indicated that application of quercetin to mouse ileum and colon on serosal side resulted in activation of CFTR and CaCC-mediated Cl− currents. Notably, we found that quercetin exhibited inhibitory effect against ANO1 chloride channel activity in ANO1-expressing FRT cells and decreased mouse intestinal motility. Quercetin-stimulated short-circuit currents in mouse ileum was multi-component, which included elevation of Ca2+ concentration through L-type calcium channel and activation of basolateral NKCC, Na+/K+-ATPase, and K+ channels. In vivo studies further revealed that quercetin promoted fluid secretion in mouse ileum. The modulatory effect of quercetin on CaCC chloirde channels may therefore represent a potential therapeutic strategy for treating CaCC-related diseases like constipation, secretory diarrhea and hypertension. The inverse effects of quercetin on CaCCs provided evidence that ANO1 and intestinal epithelial CaCCs are different calcium-activated chloride channels. PMID:27932986

  11. Pharmacologic modulation of acute ocular inflammation with quercetin.

    PubMed

    Romero, J; Marak, G E; Rao, N A

    1989-01-01

    Anti-inflammatory potentials of a safe, common dietary component, quercetin, were investigated in suppression of intraocular inflammation induced by retinal S antigen. Lewis rats sensitized to S antigen were treated daily with intraperitoneal injections of quercetin. Control rats with S-antigen-induced uveitis were similarly treated with diluent. When compared with controls the treated group showed marked reduction in uveal and retinal inflammation and in vasculitis and perivasculitis. Morphometric analysis revealed a significant reduction (p less than 0.005) in choroidal thickness when compared with that of control animals. These results clearly show the antiphlogistic effects of quercetin in experimental uveitis.

  12. Effects of quercetin and surgicel for preventing adhesions after gynecological surgery: A rat uterine horn model.

    PubMed

    Güney, Gürhan; Kaya, Cihan; Oto, Gökhan; Yıldırım, Serkan; Özdemir, Hülya; Tokmak, Aytekin

    2017-01-01

    Postoperative pelvic adhesions are significant health care problems causing chronic pelvic pain, infertility and intestinal obstruction after abdominal or pelvic surgery. We investigated the effects of quercetin and Surgicel for the prevention of adhesions after gynecological surgery. A double blind, randomized, controlled experimental study was designed. Forty female Wistar Hannover rats were divided into five groups: control, sham operated, quercetin, Surgicel, and quercetin + Surgicel. The control group received medication used for the surgical procedure only. The sham group received a laparotomy only. The quercetin group received 15 mg/kg quercetin in addition to undergoing the standard surgical procedure, and the injuries in the surgical group were covered with a single, 1 cm(2) layer of Surgicel (oxidized regenerated cellulose). The quercetin + Surgicel group received both 15 mg/kg quercetin and a single, 1 cm(2) layer of Surgicel. Adhesions were scored 14 days after the first surgical procedure. The extent, severity, degree, total adhesion, inflammation and fibrosis scores of the control group were significantly higher than those of the quercetin, Surgicel, and quercetin + Surgicel groups. There was no significant difference between the Surgicel and quercetin groups in degree, but all other parameters were significantly higher in the Surgicel than in the quercetin group. The quercetin + Surgicel group had lower adhesion scores than the quercetin group. Quercetin, Surgicel and quercetin + Surgicel treatment may be useful for preventing pelvic adhesions. © 2016 Japan Society of Obstetrics and Gynecology.

  13. Encapsulation of flavonoids in liposomal delivery systems: the case of quercetin, kaempferol and luteolin.

    PubMed

    Huang, Meigui; Su, Erzheng; Zheng, Fuping; Tan, Chen

    2017-09-20

    The instability of dietary flavonoids is currently a challenge for their incorporation in functional foods. This study investigated the protective effects of liposome encapsulation on a variety of flavonoids and their interaction mechanisms. It was found that the incorporation of flavonoids into the liposomal membrane was strongly dependent on their structure and loading concentration. Liposomes loading quercetin and luteolin exhibited a relatively small size and homogeneous suspension compared to those loading kaempferol. Additionally, liposomes displayed a stronger retaining ability to quercetin and luteolin than kaempferol during preparation, storage, heating and pH shock. After encapsulation, quercetin displayed the strongest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and lipid peroxidation inhibition capacity, followed by kaempferol and luteolin. Raman and IR spectroscopy techniques demonstrated that flavonoids could modulate the dynamic and packing order of lipid chains, which were responsible for the stabilization of liposomes. Our findings should guide the rational design of liposomal encapsulation technology to efficiently deliver flavonoids in nutraceuticals and functional foods.

  14. Quercetin Inhibits Cell Migration and Invasion in Human Osteosarcoma Cells.

    PubMed

    Lan, Haifeng; Hong, Wei; Fan, Pan; Qian, Dongyang; Zhu, Jianwei; Bai, Bo

    2017-09-21

    Osteosarcoma is a malignant tumor associated with high mortality; however, no effective therapies for the disease have been developed. Several studies have focused on elucidating the pathogenesis of osteosarcoma and have aimed to develop novel therapies for the disease. Quercetin is a vital dietary flavonoid that has been shown to have a variety of anticancer effects, as it induces cell cycle arrest, apoptosis, and differentiation and is involved in cell adhesion, metastasis and angiogenesis. Herein, we aimed to investigate the effects of quercetin on osteosarcoma migration and invasion in vitro and in vivo and to explore the molecular mechanisms underlying its effects on osteosarcoma migration and invasion. Cell viability, cell cycle activity and cell apoptosis were measured using CCK-8 assay and flow cytometry, and cell migration and invasion were evaluated by wound healing and transwell assays, respectively. The mRNA and protein expression levels of several proteins of interest were assessed by real-time quantitative PCR and western blotting, respectively. Moreover, a nude mouse model of human osteosarcoma lung metastasis was established to assess the anti-metastatic effects of quercetin in vivo. We noted no significant differences in cell cycle activity and apoptosis between HOS and MG63 cells and control cells. Treatment with quercetin significantly attenuated cell migration and invasion in HOS and MG63 cells compared with treatment with control medium. Moreover HIF-1α, VEGF, MMP2, and MMP9 mRNA and protein expression levels were significantly downregulated in HOS cells treated with quercetin compared with HOS cells treated with controls. Additionally, treatment with quercetin attenuated metastatic lung tumor formation and growth in the nude mouse model of osteosarcoma compared with treatment with controls. Our findings regarding the inhibitory effects of quercetin on cell migration and invasion suggest that quercetin may have potential as a therapy for human

  15. Actions of Quercetin, a Polyphenol, on Blood Pressure.

    PubMed

    Marunaka, Yoshinori; Marunaka, Rie; Sun, Hongxin; Yamamoto, Toshiro; Kanamura, Narisato; Inui, Toshio; Taruno, Akiyuki

    2017-01-29

    Disorder of blood pressure control causes serious diseases in the cardiovascular system. This review focuses on the anti-hypertensive action of quercetin, a flavonoid, which is one of the polyphenols characterized as the compounds containing large multiples of phenol structural units, by varying the values of various blood pressure regulatory factors, such as vascular compliance, peripheral vascular resistance, and total blood volume via anti-inflammatory and anti-oxidant actions. In addition to the anti-inflammatory and anti-oxidant actions of quercetin, we especially describe a novel mechanism of quercetin's action on the cytosolic Cl(-) concentration ([Cl(-)]c) and novel roles of the cytosolic Cl(-) i.e.: (1) quercetin elevates [Cl(-)]c by activating Na⁺-K⁺-2Cl(-) cotransporter 1 (NKCC1) in renal epithelial cells contributing to Na⁺ reabsorption via the epithelial Na⁺ channel (ENaC); (2) the quercetin-induced elevation of [Cl(-)]c in renal epithelial cells diminishes expression of ENaC leading to a decrease in renal Na⁺ reabsorption; and (3) this reduction of ENaC-mediated Na⁺ reabsorption in renal epithelial cells drops volume-dependent elevated blood pressure. In this review, we introduce novel, unique mechanisms of quercetin's anti-hypertensive action via activation of NKCC1 in detail.

  16. Molecular Targets Underlying the Anticancer Effects of Quercetin: An Update.

    PubMed

    Khan, Fazlullah; Niaz, Kamal; Maqbool, Faheem; Ismail Hassan, Fatima; Abdollahi, Mohammad; Nagulapalli Venkata, Kalyan C; Nabavi, Seyed Mohammad; Bishayee, Anupam

    2016-08-29

    Quercetin, a medicinally important member of the flavonoid family, is one of the most prominent dietary antioxidants. It is present in a variety of foods-including fruits, vegetables, tea, wine, as well as other dietary supplements-and is responsible for various health benefits. Numerous pharmacological effects of quercetin include protection against diseases, such as osteoporosis, certain forms of malignant tumors, and pulmonary and cardiovascular disorders. Quercetin has the special ability of scavenging highly reactive species, such as hydrogen peroxide, superoxide anion, and hydroxyl radicals. These oxygen radicals are called reactive oxygen species, which can cause oxidative damage to cellular components, such as proteins, lipids, and deoxyribonucleic acid. Various oxygen radicals play important roles in pathophysiological and degenerative processes, such as aging. Subsequently, several studies have been performed to evaluate possible advantageous health effects of quercetin and to collect scientific evidence for these beneficial health claims. These studies also gather data in order to evaluate the exact mechanism(s) of action and toxicological effects of quercetin. The purpose of this review is to present and critically analyze molecular pathways underlying the anticancer effects of quercetin. Current limitations and future directions of research on this bioactive dietary polyphenol are also critically discussed.

  17. Quercetin topical application, from conventional dosage forms to nanodosage forms.

    PubMed

    Hatahet, T; Morille, M; Hommoss, A; Devoisselle, J M; Müller, R H; Bégu, S

    2016-11-01

    Skin is a multifunctional organ with activities in protection, metabolism and regulation. Skin is in a continuous exposure to oxidizing agents and inflammogens from the sun and from the contact with the environment. These agents may overload the skin auto-defense capacity. To strengthen skin defense mechanisms against oxidation and inflammation, supplementation of exogenous antioxidants is a promising strategy. Quercetin is a flavonoid with very pronounced effective antioxidant and antiinflammatory activities, and thus a candidate of first choice for such skin supplementation. Quercetin showed interesting actions in cellular and animal based models, ranging from protecting cells from UV irradiation to support skin regeneration in wound healing. However, due to its poor solubility, quercetin has limited skin penetration ability, and various formulation approaches were taken to increase its dermal penetration. In this article, the quercetin antioxidant and antiinflammatory activities in wound healing and supporting skin against aging are discussed in detail. In addition, quercetin topical formulations from conventional emulsions to novel nanoformulations in terms of skin penetration enhancement are also presented. This article gives a comprehensive review of quercetin for topical application from biological effects to pharmaceutical formulation design for the last 25 years of research. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Development and evaluation of PLGA polymer based nanoparticles of quercetin.

    PubMed

    Anwer, Md Khalid; Al-Mansoor, Mohammed A; Jamil, Shahid; Al-Shdefat, Ramadan; Ansari, Mohammad Nazam; Shakeel, Faiyaz

    2016-11-01

    Quercetin is the most abundant antioxidant found in the human diet. Low aqueous solubility of quercetin limits its bioavailability and hence therapeutic effects. Therefore, the aim of the present study was to develop a poly lactide-co-glycolic acid (PLGA) polymer based nanoparticles of quercetin with a view to improve its aqueous solubility and examine the effect on its antioxidant and diuretic properties. Nanoparticles of quercetin were developed by single emulsion-solvent evaporation technique and evaluated in vitro for differential scanning calorimetry (DSC), Fourier transforms infra-red (FTIR) spectroscopy, particle size, polydispersity index and drug entrapment efficiency. Among the five different formulations (F1, F2, F3, F4 and F5), F2 and F3 were optimized with an average particle size of 189nm and 186nm and high entrapment values of 86.48%, 83.71%, respectively. SEM images of confirmed that prepared nanoparticles were spherical in shape with a smooth surface. In vitro release and anti-oxidant activity confirmed significant results. Furthermore, its in vivo diuretic activity was much better as compared to pure quercetin. The overall results suggest that PLGA polymer based nanoparticle could be a potential option for quercetin delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. [Health--promoting effect of quercetin in human diet].

    PubMed

    Kobylińska, Agnieszka; Janas, Krystyna M

    2015-01-09

    Quercetin is a plant flavonoid phytochemical exhibiting a broad spectrum of properties i.a. antioxidant, anti-inflammatory and immunomodulatory. However, the effect of quercetin is not clear. This compound at low concentrations can stimulate proliferation of human cells, so it can be a potential drug in the treatment of neurodegenerative diseases and in high concentrations, it induces apoptosis thereby eliminating the infected or abnormal cells and can serve as a potential anticancer drug with wide clinical application. Action of quercetin can be explained by its interference with cellular enzymes, receptors, transporters and signalling system. Due to its widespread occurrence in the plant world, it is an integral component of the human diet. The dietary quercetin occurs most often in the form of β-glycosides connected mostly with rutinose, rhamnose and glucose. Depending on the nutritional habits, the daily intake of flavonoids, including quercetin, ranges from 3 to 70 mg. Epidemiological studies confirm an inverse correlation between the consumption of flavonoids and the incidence of lifestyle diseases and tumor formation. Published data indicate that consumption of foods rich in flavonoids reduces the risk of coronary heart disease. Thus, flavonoids - including quercetin - seem to be an interesting pro-health agent.

  20. Molecular Targets Underlying the Anticancer Effects of Quercetin: An Update

    PubMed Central

    Khan, Fazlullah; Niaz, Kamal; Maqbool, Faheem; Ismail Hassan, Fatima; Abdollahi, Mohammad; Nagulapalli Venkata, Kalyan C.; Nabavi, Seyed Mohammad; Bishayee, Anupam

    2016-01-01

    Quercetin, a medicinally important member of the flavonoid family, is one of the most prominent dietary antioxidants. It is present in a variety of foods—including fruits, vegetables, tea, wine, as well as other dietary supplements—and is responsible for various health benefits. Numerous pharmacological effects of quercetin include protection against diseases, such as osteoporosis, certain forms of malignant tumors, and pulmonary and cardiovascular disorders. Quercetin has the special ability of scavenging highly reactive species, such as hydrogen peroxide, superoxide anion, and hydroxyl radicals. These oxygen radicals are called reactive oxygen species, which can cause oxidative damage to cellular components, such as proteins, lipids, and deoxyribonucleic acid. Various oxygen radicals play important roles in pathophysiological and degenerative processes, such as aging. Subsequently, several studies have been performed to evaluate possible advantageous health effects of quercetin and to collect scientific evidence for these beneficial health claims. These studies also gather data in order to evaluate the exact mechanism(s) of action and toxicological effects of quercetin. The purpose of this review is to present and critically analyze molecular pathways underlying the anticancer effects of quercetin. Current limitations and future directions of research on this bioactive dietary polyphenol are also critically discussed. PMID:27589790

  1. Report: quantitative estimation of beta-sitosterol, lupeol, quercetin and quercetin glycosides from leaflets of Soymida febrifuga using HPTLC technique.

    PubMed

    Attarde, D L; Aurangabadkar, V M; Belsare, D P; Pal, S C

    2008-07-01

    Soymida febrifuga (Meliaceae) dried leaflets (10 gm) were extracted with petroleum ether. Unsaponifiable matter quantitatively used for sample preparation, labeled as SF-U. Another 10 gm leaflet powder was extracted with methanol and quantitatively used for sample preparation labeled as SF-A. Sample and standard solution were dosage on three different plates and developed in its respective mobile phase plates were scanned using TLC scanner III and estimated using integration software CATs 4.05. Calculations for percentage were done considering standard and sample R(f), AUC and dilution factor. Estimation of beta Sitosterol, Lupeol, Quercetin, Quercetin-3-O-galactoside, Quercetin-3-O-xyloside and Quercetin-3-O-rutinoside were determined as 0.02146% w/w, 0.0377% w/w, 0.4079% w/w, 0.6197% w/w, 2.974% w/w and 3.235% w/w respectively with the help of HPLC techniques.

  2. Quercetin derivatives as non-nucleoside inhibitors for dengue polymerase: molecular docking, molecular dynamics simulation, and binding free energy calculation.

    PubMed

    Anusuya, Shanmugam; Gromiha, M Michael

    2017-10-01

    Dengue is an important public health problem in tropical and subtropical regions of the world. Neither vaccine nor an antiviral medication is available to treat dengue. This insists the need of drug discovery for dengue. In order to find a potent lead molecule, RNA-dependent RNA polymerase which is essential for dengue viral replication is chosen as a drug target. As Quercetin showed antiviral activity against several viruses, quercetin derivatives developed by combinatorial library synthesis and mined from PubChem databases were screened for a potent anti-dengue viral agent. Our study predicted Quercetin 3-(6″-(E)-p-coumaroylsophoroside)-7-rhamnoside as a dengue polymerase inhibitor. The results were validated by molecular dynamics simulation studies which reveal water bridges and hydrogen bonds as major contributors for the stability of the polymerase-lead complex. Interactions formed by this compound with residues Trp795, Arg792 and Glu351 are found to be essential for the stability of the polymerase-lead complex. Our study demonstrates Quercetin 3-(6″-(E)-p-coumaroylsophoroside)-7-rhamnoside as a potent non-nucleoside inhibitor for dengue polymerase.

  3. Sol-gel synthesis and characterization of SiO2/PCL hybrid materials containing quercetin as new materials for antioxidant implants.

    PubMed

    Catauro, Michelina; Bollino, Flavia; Papale, Ferdinando; Piccolella, Simona; Pacifico, Severina

    2016-01-01

    The development of biomaterials with intrinsic antioxidant properties could represent a valuable strategy for preventing peri-implant disease onset. In this context quercetin, a naturally occurring flavonoid, has been entrapped, at different weight percentages in a silica/poly(ε-caprolactone)-based hybrid material by a sol-gel route. FT-IR and UV spectroscopic techniques were employed in order to characterize the hybrids. FT-IR analysis indicated changes in stretching frequencies of the quercetin dienonic moiety, suggesting that a flavonol oxidized derivative was formed during the sol-gel process. The establishment of hydrogen-bonded interactions between quercetin and silica and polymer matrices,was strongly affected by the amount of polymer. Poly(ε-caprolactone) did not interact with quercetin when it was loaded at high doses (50 wt.%). The morphology of the synthesized materials was observed by using SEM. The obtained images proved that the materials are hybrid nanocomposites. Their bioactivity was shown by the formation of a hydroxyapatite layer on samples' surface soaked in a fluid simulating the composition of the human plasma. The antiradical properties of the investigated systems were evaluated by DPPH and ABTS methods and their cytotoxicity by the MTT assay. Data obtained revealed that the synthesized materials are biocompatible and that the hybrid system,with 6 wt.% of PCL and 15 wt.% of quercetin, produced the strongest antiradical efficacy.

  4. Effects of quercetin and quercetin-3-O-glycosides on oxidative damage in rat C6 glioma cells.

    PubMed

    Zielińska, Małgorzata; Gülden, Michael; Seibert, Hasso

    2003-01-01

    Flavonoids are reported to be powerful antioxidants in cell free systems. They naturally occur as glycosides rather than as aglycon. In this study the ability of the flavonoid quercetin and its glycosides, quercetin-3-O-rutinoside (rutin), quercetin-3-O-glucoside and quercetin-3-O-(6″-O-acetyl)-glucoside, to protect in vitro rat C6 glioma cells from oxidative damage induced by cumene hydroperoxide was investigated. Cumene hydroperoxide induced cell death and lipid peroxidation. The cytotoxicity of cumene hydroperoxide could be prevented by the radical scavenger dimethyl thiourea and the ferric iron chelator deferoxamine, indicating that its cytotoxic activity is related to the generation of reactive oxygen radicals in the ferrous iron dependent Fenton reaction. Quercetin, in a concentration range of 10-100 μM, but neither rutin nor the other two glycosides, were able to protect C6 cells from cytotoxicity and lipid peroxidation. Furthermore, cytoprotective concentrations of quercetin proved to be cytotoxic itself. These results call in question potential beneficial effects of dietary intake or therapeutic use of naturally occurring flavonoids.

  5. Dietary quercetin supplementation is not ergogenic in untrained men.

    PubMed

    Cureton, Kirk J; Tomporowski, Phillip D; Singhal, Arpit; Pasley, Jeffrey D; Bigelman, Kevin A; Lambourne, Kathleen; Trilk, Jennifer L; McCully, Kevin K; Arnaud, Maurice J; Zhao, Qun

    2009-10-01

    Quercetin supplementation increases muscle oxidative capacity and endurance in mice, but its ergogenic effect in humans has not been established. Our study investigates the effects of short-duration chronic quercetin supplementation on muscle oxidative capacity; metabolic, perceptual, and neuromuscular determinants of performance in prolonged exercise; and cycling performance in untrained men. Using a double-blind, pretest-posttest control group design, 30 recreationally active, but not endurance-trained, young men were randomly assigned to quercetin and placebo groups. A noninvasive measure of muscle oxidative capacity (phosphocreatine recovery rate using magnetic resonance spectroscopy), peak oxygen uptake (Vo(2peak)), metabolic and perceptual responses to submaximal exercise, work performed on a 10-min maximal-effort cycling test following the submaximal cycling, and voluntary and electrically evoked strength loss following cycling were measured before and after 7-16 days of supplementation with 1 g/day of quercetin in a sports hydration beverage or a placebo beverage. Pretreatment-to-posttreatment changes in phosphocreatine recovery time constant, Vo(2peak,) substrate utilization, and perception of effort during submaximal exercise, total work done during the 10-min maximal effort cycling trial, and voluntary and electrically evoked strength loss were not significantly different (P > 0.05) in the quercetin and placebo groups. Short duration, chronic dietary quercetin supplementation in untrained men does not improve muscle oxidative capacity; metabolic, neuromuscular and perceptual determinants of performance in prolonged exercise; or cycling performance. The null findings indicate that metabolic and physical performance consequences of quercetin supplementation observed in mice should not be generalized to humans.

  6. Inhibition of oxidative hemolysis by quercetin, but not other antioxidants.

    PubMed

    Hapner, Christopher D; Deuster, Patricia; Chen, Yifan

    2010-08-05

    We previously reported that lipid-soluble quercetin, not water-soluble dihydroquercetin, protects human red blood cells against oxidative damage. The objectives of this study were to determine if an antihemolytic effect could be produced by other lipid-soluble antioxidants and if anti-inflammatory activity played a role in antihemolysis by quercetin. This study compared three lipid-soluble polyphenols, muscadine, curcumin and quercetin, and three lipid- (alpha-tocopherol and alpha-tocotrienol) or water-soluble (ascorbic acid) vitamins. Among the tested polyphenols, muscadine was the most potent in inhibiting superoxide and 2,2-azobis(2-amidinopropane) dihydrochloride (AAPH)-generated peroxyl radicals, whereas ascorbic acid was the most potent inhibitor of hydrogen peroxide. Activities of the polyphenols after lipid extractions showed that curcumin inhibited superoxide production to a greater extent than quercetin and muscadine. All blood cells were tested 20 min after incubation with the selected compounds. All the polyphenols caused inhibition of N-formyl-l-methionyl-l-leucyl-l-phenylalanine-induced neutrophil oxidative bursts. Quercetin, but not other polyphenols, significantly reduced AAPH-induced oxidative hemolysis. No significant effect on neutrophil oxidative burst or oxidative hemolysis was found with any of the tested vitamins. These results suggest that quercetin enhances the resistance of membrane to destruction by free radicals. This effect of quercetin is not directly mediated through antioxidative or anti-inflammatory actions. Antioxidant or anti-inflammatory potency may not be used as a simple criterion to select polyphenols for cell protection benefits. Published by Elsevier Ireland Ltd.

  7. Pharmacokinetic comparison between quercetin and quercetin 3-O-β-glucuronide in rats by UHPLC-MS/MS

    NASA Astrophysics Data System (ADS)

    Yang, Le-Le; Xiao, Na; Li, Xiao-Wei; Fan, Yong; Alolga, Raphael N.; Sun, Xiao-Yue; Wang, Shi-Lei; Li, Ping; Qi, Lian-Wen

    2016-10-01

    Quercetin is a natural flavonoid widely distributed in human diet and functional foods. Quercetin 3-O-β-glucuronide (Q3G) is present in wine and some medicinal plants. Quercetin and Q3G may be metabolized from each other in vivo. While quercetin has been the subject of many studies, the pharmacokinetic profiles of quercetin and Q3G (in animals) have not yet been compared. Herein, we prepared a column-based method for rapid isolation of Q3G from Nelumbo nucifera. Then, we developed an UHPLC-MS/MS method to compare the pharmacokinetics of quercetin and Q3G. Our results showed that the plasma concentration-time curves of quercetin and Q3G show two maxima (Tmax1 ≈ 0.75 h, Tmax2 ≈ 5 h). After oral administration of 100 mg/kg quercetin or 100 mg/kg Q3G in rats, predominantly Q3G was detected in plasma with AUC at 39529.2 ± 6108.2 mg·h·L‑1 or 24625.1 ± 1563.8 mg·h·L‑1, 18-fold higher than quercetin with AUC at 1583.9 ± 583.3 mg·h·L‑1 or 1394.6 ± 868.1 mg·h·L‑1, respectively. After intravenous injection of 10 mg/kg in rats, Q3G showed extensive tissue uptake in kidney (409.2 ± 118.4 ng/g), liver (166.1 ± 52.9 ng/g), heart (97.7 ± 22.6 ng/g), and brain (5.8 ± 1.2 ng/g). In conclusion, we have shown that Q3G is a major active component in plasma and tissue for oral administration of quercetin or Q3G.

  8. Pharmacokinetic comparison between quercetin and quercetin 3-O-β-glucuronide in rats by UHPLC-MS/MS

    PubMed Central

    Yang, Le-Le; Xiao, Na; Li, Xiao-Wei; Fan, Yong; Alolga, Raphael N.; Sun, Xiao-Yue; Wang, Shi-Lei; Li, Ping; Qi, Lian-Wen

    2016-01-01

    Quercetin is a natural flavonoid widely distributed in human diet and functional foods. Quercetin 3-O-β-glucuronide (Q3G) is present in wine and some medicinal plants. Quercetin and Q3G may be metabolized from each other in vivo. While quercetin has been the subject of many studies, the pharmacokinetic profiles of quercetin and Q3G (in animals) have not yet been compared. Herein, we prepared a column-based method for rapid isolation of Q3G from Nelumbo nucifera. Then, we developed an UHPLC-MS/MS method to compare the pharmacokinetics of quercetin and Q3G. Our results showed that the plasma concentration-time curves of quercetin and Q3G show two maxima (Tmax1 ≈ 0.75 h, Tmax2 ≈ 5 h). After oral administration of 100 mg/kg quercetin or 100 mg/kg Q3G in rats, predominantly Q3G was detected in plasma with AUC at 39529.2 ± 6108.2 mg·h·L−1 or 24625.1 ± 1563.8 mg·h·L−1, 18-fold higher than quercetin with AUC at 1583.9 ± 583.3 mg·h·L−1 or 1394.6 ± 868.1 mg·h·L−1, respectively. After intravenous injection of 10 mg/kg in rats, Q3G showed extensive tissue uptake in kidney (409.2 ± 118.4 ng/g), liver (166.1 ± 52.9 ng/g), heart (97.7 ± 22.6 ng/g), and brain (5.8 ± 1.2 ng/g). In conclusion, we have shown that Q3G is a major active component in plasma and tissue for oral administration of quercetin or Q3G. PMID:27775094

  9. Investigation of function similarities between the sarcoplasmic reticulum and platelet calcium-dependent adenosinetriphosphatases with the inhibitors quercetin and calmidazolium

    SciTech Connect

    Fischer, T.H.; Campbell, K.P.; White, G.C. II

    1987-12-01

    The platelet and skeletal sarcoplasmic reticulum calcium-dependent adenosinetriphosphatases (Ca/sup 2 +/-ATPases) were functionally compared with respect to substrate activation by steady-state kinetic methods using the inhibitors quercetin and calmidazolium. Quercetin inhibited platelet and sarcoplasmic reticulum Ca/sup 2 +/-ATPase activities in a dose-dependent manner with IC/sub 50/ values of 25 and 10 ..mu..M, respectively. Calmidazolium also inhibited platelet and sarcoplasmic reticulum Ca/sup 2 +/-ATPase activities, with half-maximal inhibition measured at 5 and 4 ..mu..M, respectively. Both inhibitors also affected the (/sup 45/Ca) calcium transport activity of intact platelet microsomes at concentrations similar to those which reduced Ca/sup 2 +/-ATPase activity. These inhibitors were then used to examine substrate ligation by the platelet and sarcoplasmic reticulum calcium pump proteins. For both Ca/sup 2 +/-ATPase proteins, quercetin has an affinity for the E-Ca/sub 2/ (fully ligated with respect to calcium at the exterior high-affinity calcium binding sites, unligated with respect to ATP) conformational state of the protein that is approximately 10-fold grater than for other conformational states in the hydrolytic cycle. Quercetin can thus be considered a competitive inhibitor of the calcium pump proteins with respect to ATP. In contrast to the effect of quercetin, calmidazolium interacts with the platelet and sarcoplasmic reticulum Ca/sup 2 +/-ATPases in an uncompetitive manner. The dissociation constants for this inhibitor for the different conformational states of the calcium pump proteins were similar, indicating that calmidazolium has equal affinity for all of the reaction intermediates probed. These observations indicate that the substrate ligation processes are similar for the two pump proteins. This supports the concept that the hydrolytic cycles of the two proteins are comparable.

  10. Antioxidant Activity of Quercetin and Its Glucosides from Propolis: A Theoretical Study.

    PubMed

    Zheng, Yan-Zhen; Deng, Geng; Liang, Qin; Chen, Da-Fu; Guo, Rui; Lai, Rong-Cai

    2017-08-08

    Among the multiple components of propolis, flavonoids contribute greatly to the antioxidant activities of propolis. Flavonoids mainly exist in the form of sugar-conjugated derivatives. Quercetin glycosides represent the predominant flavonoid fraction in propolis. In this work, density functional theory (DFT) calculations were applied to analyze the antioxidative properties of quercetin and its glucosides in the gas and in the liquid phase (ethanol, water). Three main antioxidant mechanisms, hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET) were used to analyze the antioxidative capacity of the investigated compounds. Solvent effects dominantly affect SET-PT and SPLET. Thus, the thermodynamically preferred mechanism can be altered. HAT and SPLET are the thermodynamically dominant mechanisms in gas and solvent phases, respectively. Therefore, in the gas phase, the sequence of the antioxidative capacity is similar with the bond dissociation enthalpy values: quercetin > quercetin-5-O-glucoside > quercetin-7-O-glucoside > quercetin-3-O-glucoside > quercetin-3'-O-glucoside > quercetin-4'-O-glucoside. While, in the solvent phases, the sequence is similar with the proton affinity values: quercetin-4'-O-glucoside > quercetin-5-O-glucoside > quercetin > quercetin-3-O-glucoside > quercetin-7-O-glucoside > quercetin-3'-O-glucoside. OH groups in B-ring and C-ring contribute mainly to the antioxidative activities of quercetin and glucosides compared with A-ring.

  11. Suppressive Activity of Quercetin on Periostin Functions In Vitro.

    PubMed

    Irie, Shinji; Kashiwabara, Misako; Yamada, Asako; Asano, Kazuhito

    2016-01-01

    Periostin, a 90-kDa extracellular matrix protein, has been attracting attention as a novel biomarker of airway inflammatory diseases such as allergic rhinitis (AR) and asthma. Although oral administration of quercetin to patients with AR can favorably modify the clinical condition of this disease, the influence of quercetin on periostin functions is not well understood. The present study was, therefore, undertaken to examine the influence of quercetin on the production of both periostin and periostin-induced eosinophil chemoattractants from human nasal epithelial cells (HNEpC) in vitro. HNEpC were stimulated with 15.0 ng/ml interleukin (IL)-4 in the absence or presence of quercetin for 72 h. Periostin levels in the culture supernatants were measured using enzyme-linked immunosorbent assay (ELISA). Addition of 4.0 μM quercetin into cell cultures suppressed periostin production from HNEpC that was induced by IL-4 stimulation through inhibitation of signal transducer and activator of transcription 6 (STAT6) activation. We then examined whether quercetin could inhibit production of the periostin-induced eosinophil chemoattractants, regulated on activation, normal T-cell expressed and secreted (RANTES) and eotaxin, from HNEpC. HNEpC were stimulated with 2.0 ng/ml periostin in the absence or presence of quercetin for 72 h. RANTES and eotaxin levels in culture supernatants were examined using ELISA. Treatment of HNEpC with quercetin at a concentration of 4.0 μM suppressed the ability of cells to produce RANTES and eotaxin. This suppression was mediated through suppression of activation of the transcription factor nuclear factor-kappa B (NF-κB) p65, as measured using ELISA, and of chemokine mRNA expression, as measured using reverse transcriptase-polymerase chain reaction (RT-PCR). These results strongly suggest that quercetin suppresses the production of both periostin and periostin-induced eosinophil chemoattractants from HNEpC and results in improvement of the

  12. Quercetin and quercetin 3-O-glycosides from Bauhinia longifolia (Bong.) Steud. show anti-Mayaro virus activity

    PubMed Central

    2014-01-01

    Background The arthropod-borne Mayaro virus (MAYV) causes ‘Mayaro fever’, a disease of medical significance, primarily affecting individuals in permanent contact with forested areas in tropical South America. Recently, MAYV has attracted attention due to its likely urbanization. Currently, there are no licensed drugs against most mosquito-transmitted viruses. Here, we investigated the in vitro anti-MAYV activity of the flavonoids quercetin and its derivatives from the Brazilian shrub Bauhinia longifolia (Bong.) Steud. Methods Flavonoids were purified by chromatographic fractionation from leaf extracts of B. longifolia and chemically identified as quercetin and quercetin glycosides using spectroscopic techniques. Cytotoxicity of purified flavonoids and of EtOAc- and n-BuOH-containing flavonoid mixtures was measured by the dye-uptake assay while their antiviral activity was evaluated by a virus yield inhibition assay. Results The following flavonoids were purified from B. longifolia leaves: non-glycosylated quercetin and its glycosides guaijaverin, quercitrin, isoquercitrin, and hyperin. EtOAc and n-BuOH fractions containing these flavonoids demonstrated the highest antiviral activity of all tested substances, while quercetin had the highest antiviral activity amongst purified flavonoids. Quercetin, EtOAc, or n-BuOH fractions inhibited MAYV production by more than 90% at 25 μg/mL, displaying a stronger antiviral effect than the licensed antiviral ribavirin. A mixture of the isomers isoquercitrin and hyperin had a modest antiviral effect (IC90 = 104.9), while guaijaverin and quercitrin did not show significant antiviral activity. Conclusions B. longifolia is a good source of flavonoids with anti-Mayaro virus activity. This is the first report of the activity of quercetin and its derivatives against an alphavirus. PMID:24678592

  13. Quercetin and quercetin 3-O-glycosides from Bauhinia longifolia (Bong.) Steud. show anti-Mayaro virus activity.

    PubMed

    dos Santos, Alda E; Kuster, Ricardo M; Yamamoto, Kristie A; Salles, Tiago S; Campos, Renata; de Meneses, Marcelo D F; Soares, Márcia R; Ferreira, Davis

    2014-03-28

    The arthropod-borne Mayaro virus (MAYV) causes 'Mayaro fever', a disease of medical significance, primarily affecting individuals in permanent contact with forested areas in tropical South America. Recently, MAYV has attracted attention due to its likely urbanization. Currently, there are no licensed drugs against most mosquito-transmitted viruses. Here, we investigated the in vitro anti-MAYV activity of the flavonoids quercetin and its derivatives from the Brazilian shrub Bauhinia longifolia (Bong.) Steud. Flavonoids were purified by chromatographic fractionation from leaf extracts of B. longifolia and chemically identified as quercetin and quercetin glycosides using spectroscopic techniques. Cytotoxicity of purified flavonoids and of EtOAc- and n-BuOH-containing flavonoid mixtures was measured by the dye-uptake assay while their antiviral activity was evaluated by a virus yield inhibition assay. The following flavonoids were purified from B. longifolia leaves: non-glycosylated quercetin and its glycosides guaijaverin, quercitrin, isoquercitrin, and hyperin. EtOAc and n-BuOH fractions containing these flavonoids demonstrated the highest antiviral activity of all tested substances, while quercetin had the highest antiviral activity amongst purified flavonoids. Quercetin, EtOAc, or n-BuOH fractions inhibited MAYV production by more than 90% at 25 μg/mL, displaying a stronger antiviral effect than the licensed antiviral ribavirin. A mixture of the isomers isoquercitrin and hyperin had a modest antiviral effect (IC90 = 104.9), while guaijaverin and quercitrin did not show significant antiviral activity. B. longifolia is a good source of flavonoids with anti-Mayaro virus activity. This is the first report of the activity of quercetin and its derivatives against an alphavirus.

  14. Effect of Naringenin, Quercetin, and Sesamin on Xenobiotica-Metabolizing CYP1A and CYP3A in Mice Offspring after Maternal Exposure to Persistent Organic Pollutants.

    PubMed

    Pilipenko, Nadezhda; Ropstad, Erik; Halsne, Ruth; Zamaratskaia, Galia

    2017-01-01

    The aim of the present study was to evaluate in vitro effects of dietary phytochemicals naringenin, quercetin, and sesamin on the activities of ethoxy- (EROD; CYP1A) and benzyloxy- (BROD; CYP3A) resorufin O-dealkylases after the exposure to the cocktail of persistent organic pollutants (POPs). CD-1 mice were exposed from weaning, through gestation and lactation to a defined mixture of POPs. Hepatic microsomes were prepared from their female offspring at postnatal day 42. Hepatic EROD and BROD activity were evaluated in the presence of quercetin, naringenin, and sesamin at nine concentrations from 5 to 100000 nM. EROD activity was strongly inhibited by quercetin with Ki values from 1.7 to 2.6 μM. BROD activity was inhibited by quercetin with Ki values from 64.9 to 75.3 μM and naringenin with Ki values from 39.3 to 45.8 μM. The IC50 and Ki values did not differ between the groups of mice with different levels of POPs exposure in any of the experimental sets. Sesamin did not inhibit either EROD or BROD. We concluded that the interactions of quercetin and naringenin with CYP1A and CYP3A in mice liver were not affected by the levels of POPs exposure.

  15. Quercetin and rutin as potential agents antifungal against Cryptococcus spp.

    PubMed

    Oliveira, V M; Carraro, E; Auler, M E; Khalil, N M

    2016-01-01

    Amphotericin B is a fungicidal substance that is treatment of choice for most systemic fungal infections affecting as cryptococcosis the immunocompromised patients. However, severe side effects have limited the utility of this drug. The aim of this study was to evaluate the antifungal effect of the combination of amphotericin B with quercetin or rutin and as a protective of citotoxic effect. The antifungal activity to amphotericin B, quercetin and rutin alone and in combination was determined in Candida sp and Cryptococcus neoformans strains. Cytotoxicity test on erythrocytes was performed by spectrophotometric absorbance of hemoglobin. The amphotericin B MIC was reduced when used in combination with quercetin or rutin to C. neoformans ATCC strain and reduced when combined with rutin to a clinical isolate of C. neoformans. In addition, the combination of quercetin with amphotericin B may reduce the toxicity of amphotericin B to red blood cells. Our results suggest that quercetin and rutin are potential agents to combine with amphotericin B in order to reduce the amphotericin dose to lessen side effects and improve antifungal efficacy.

  16. The effect of quercetin and galangin on glutathione reductase.

    PubMed

    Paulíková, Helena; Berczeliová, Elena

    2005-12-01

    Quercetin and galangin can change the activity of glutathione reductase. Quercetin (a catechol structure in the B-ring) and galangin (any hydroxyl group in the B-ring) have different biological activities but, both possess high antioxidant abilities. Quercetin during the antioxidative action, is converted into an oxidized products (o-semiquinone and o-quinone), and subsequently glutathionyl adducts may be formed or SH-enzyme can be inhibited. We have tried to see whether inhibition of glutathione reductase (GR) can be influenced by preincubation of enzyme with NADPH (a creation of reduced form of enzyme, GRH(2)) and whether diaphorase activity of the enzyme is decreased by these flavonoids. The results confirmed that quercetin inhibits GRH(2) and inhibition is reduced by addition of EDTA or N-acetylcysteine. Both of flavonoids have no effect on diaphorase activity of glutathione reductase and this enzyme could increase the production of free radicals by catalysis of reduction of o-quinone during action of quercetin in vivo.

  17. Mechanisms of Neuroprotection by Quercetin: Counteracting Oxidative Stress and More

    PubMed Central

    Costa, Lucio G.; Garrick, Jacqueline M.; Roquè, Pamela J.; Pellacani, Claudia

    2016-01-01

    Increasing interest has recently focused on determining whether several natural compounds, collectively referred to as nutraceuticals, may exert neuroprotective actions in the developing, adult, and aging nervous system. Quercetin, a polyphenol widely present in nature, has received the most attention in this regard. Several studies in vitro, in experimental animals and in humans, have provided supportive evidence for neuroprotective effects of quercetin, either against neurotoxic chemicals or in various models of neuronal injury and neurodegenerative diseases. The exact mechanisms of such protective effects remain elusive, though many hypotheses have been formulated. In addition to a possible direct antioxidant effect, quercetin may also act by stimulating cellular defenses against oxidative stress. Two such pathways include the induction of Nrf2-ARE and induction of the antioxidant/anti-inflammatory enzyme paraoxonase 2 (PON2). In addition, quercetin has been shown to activate sirtuins (SIRT1), to induce autophagy, and to act as a phytoestrogen, all mechanisms by which quercetin may provide its neuroprotection. PMID:26904161

  18. The Phototoxic Potential of the Flavonoids, Taxifolin and Quercetin.

    PubMed

    Rajnochová Svobodová, Alena; Ryšavá, Alena; Psotová, Michaela; Kosina, Pavel; Zálešák, Bohumil; Ulrichová, Jitka; Vostálová, Jitka

    2017-10-01

    Quercetin, one of the most abundant polyphenols in the plant kingdom has been shown to be photodegraded on exposure to UV light. Despite the fact, it is a component of several dermatological preparations. Its phototoxic potential has not been evaluated to date. The aim of this study was to assess whether photo-induced degradation of quercetin is linked to phototoxic effects on living cells. Its dihydro derivative, taxifolin, was included in the study. For evaluation, the 3T3 Neutral Red Uptake Phototoxicity Test according to OECD TG 432 was used. To better approximate human skin, HaCaT keratinocytes, normal human epidermal keratinocytes and dermal fibroblasts were used, apart from the Balb/c 3T3 cell line. Quercetin showed a dose-dependent photodegradation in aqueous and organic environments and a phototoxic effect on all used cells. Quercetin pretreatment and following UVA exposure resulted in increased reactive oxygen species production and intracellular glutathione level depletion in human dermal fibroblasts. Taxifolin was found completely nonphototoxic and photostable. As only in vitro methodology was used, further studies using 3D skin models and/or human volunteers are needed to confirm whether exposure to sunlight, tanning sunbeds and/or phototherapy in people using cosmetics containing quercetin is a health risk. © 2017 The American Society of Photobiology.

  19. Site-specific anticancer effects of dietary flavonoid quercetin.

    PubMed

    Sak, Katrin

    2014-01-01

    Food-derived flavonoid quercetin, widely distributed in onions, apples, and tea, is able to inhibit growth of various cancer cells indicating that this compound can be considered as a good candidate for anticancer therapy. Although the exact mechanism of this action is not thoroughly understood, behaving as antioxidant and/or prooxidant as well as modulating different intracellular signalling cascades may all play a certain role. Such inhibitory activity of quercetin has been shown to depend first of all on cell lines and cancer types; however, no comprehensive site-specific analysis of this effect has been published. In this review article, cytotoxicity constants of quercetin measured in various human malignant cell lines of different origin were compiled from literature and a clear cancer selective action was demonstrated. The most sensitive malignant sites for quercetin revealed to be cancers of blood, brain, lung, uterine, and salivary gland as well as melanoma whereas cytotoxic activity was higher in more aggressive cells compared to the slowly growing cells showing that the most harmful cells for the organism are probably targeted. More research is needed to overcome the issues of poor water solubility and relatively low bioavailability of quercetin as the major obstacles limiting its clinical use.

  20. Dietary flavonoid quercetin stimulates vasorelaxation in aortic vessels.

    PubMed

    Khoo, Nicholas K H; White, C Roger; Pozzo-Miller, Lucas; Zhou, Fen; Constance, Chad; Inoue, Takafumi; Patel, Rakesh P; Parks, Dale A

    2010-08-01

    Considerable epidemiological evidence indicates that dietary consumption of moderate levels of polyphenols decreases both the incidence of cardiovascular disease and the mortality associated with myocardial infarction. Molecular mechanisms of this cardiovascular protection remain uncertain but can involve changes in rates of nitric oxide (NO) generation by endothelial nitric oxide synthase (eNOS). We examined the vascular responses to quercetin using a combination of biochemical and vessel function criteria. Quercetin treatment for 30min enhanced relaxation of rat aortic ring segments. Moreover, the addition of L-NAME (100muM) or charybdotoxin (ChTx) blocked quercetin-mediated vasorelaxation thus demonstrating the effect was partially dependent on NOS and endothelium-derived hyperpolarizing factor (EDHF). Additionally, bovine aortic endothelial cells (BAEC) treated with quercetin showed a rapid increase of intracellular Ca(2+) concentrations as well as a dose- and time-dependent stimulation of eNOS phosphorylation with a concomitant increase in NO production. These results demonstrate that quercetin-mediated stimulation of eNOS phosphorylation increases NO bioavailability in endothelial cells and can thus play a role in the vascular protective effects associated with improved endothelial cell function.

  1. Protective Effect of Quercetin on Posttraumatic Cardiac Injury

    PubMed Central

    Jing, Zehao; Wang, Zhuorun; Li, Xiujie; Li, Xintao; Cao, Tingting; Bi, Yue; Zhou, Jicheng; Chen, Xu; Yu, Deqin; Zhu, Liang; Li, Shuzhuang

    2016-01-01

    Quercetin is an important dietary flavonoid present in fruits and vegetables and has attracted attention because of its anti-inflammatory and anti-oxidative properties. Inflammation and oxidative stress play important roles in posttraumatic cardiomyocyte apoptosis, which contributes to secondary cardiac dysfunction. This study investigates the protective effect of quercetin on trauma-induced secondary cardiac injury and the mechanisms involved. Widely accepted nonlethal mechanical trauma models were established. In vivo, cardiomyocyte apoptosis and cardiac dysfunction in rats were assessed using TUNEL staining and a biological mechanic experiment system. In vitro, cell viability, tumour necrosis factor-α (TNF-α), reactive oxygen species (ROS) and [Ca2+]i of H9c2 cells were detected using an MTT assay, ELISA, and 2′,7′-dichlorofluorescin diacetate and fluo-4 acetoxymethyl ester assays respectively. Quercetin pretreatment (20 mg/kg i.p.; 0.5 h before trauma) significantly improved posttraumatic cardiomyocyte apoptosis and cardiac dysfunction. Pretreatment with quercetin (20 μM; 24 h before trauma plasma addition) significantly attenuated trauma-induced viability decreases, TNF-α increases, ROS overproduction and [Ca2+]i overload in H9c2 cells. In conclusion, quercetin may reverse posttraumatic cardiac dysfunction by reducing cardiomyocyte apoptosis through the suppression of TNF-α increases, ROS overproduction and Ca2+ overload in cardiomyocytes, representing a potential preventive approach for the treatment of secondary cardiac injury after mechanical trauma. PMID:27470932

  2. DIETARY FLAVONOID QUERCETIN STIMULATES VASORELAXATION IN AORTIC VESSELS

    PubMed Central

    Khoo, Nicholas K.H.; White, C. Roger; Pozzo-Miller, Lucas; Zhou, Fen; Constance, Chad; Inoue, Takafumi; Patel, Rakesh P.; Parks, Dale A.

    2010-01-01

    Considerable epidemiological evidence indicates that dietary consumption of moderate levels of polyphenols decreases both the incidence of cardiovascular disease and the mortality associated with myocardial infarction. Molecular mechanisms of this cardiovascular protection remain uncertain but can involve changes in rates of nitric oxide (NO) generation by endothelial nitric oxide synthase (eNOS). We examined the vascular responses to quercetin using a combination of biochemical and vessel function criteria. Quercetin treatment for 30 min enhanced relaxation of rat aortic ring segments. Moreover, the addition of L-NAME (100 μM) or charybdotoxin (ChTx) blocked quercetin-mediated vasorelaxation thus demonstrating the effect was partially dependent on NOS and endothelium-derived hyperpolarizing factor (EDHF). Additionally, bovine aortic endothelial cells (BAEC) treated with quercetin showed a rapid increase of intracellular Ca2+ concentrations as well as a dose- and time-dependent stimulation of eNOS phosphorylation with a concomitant increase in NO production. These results demonstrate that quercetin-mediated stimulation of eNOS phosphorylation increases NO bioavailability in endothelial cells and can thus play a role in the vascular protective effects associated with improved endothelial cell function. PMID:20423726

  3. Risk of Prostate Cancer in African American Men: Evidence of Mixed Effects of Dietary Quercetin by Serum Vitamin D Status

    PubMed Central

    Paller, CJ; Kanaan, YM; Beyene, DA; Naab, TJ; Copeland, RL; Tsai, HL; Kanarek, NF; Hudson, TS

    2015-01-01

    Background African American (AA) men experience higher rates of prostate cancer (PCa) and vitamin D (vitD) deficiency than white men. VitD is promoted for PCa prevention, but there is conflicting data on the association between vitD and PCa. We examined the association between serum vitD and dietary quercetin and their interaction with PCa risk in AA men. Methods Participants included 90 AA men with PCa undergoing treatment at Howard University Hospital (HUH) and 62 controls participating in HUH’s free PCa screening program. We measured serum 25-hydroxy vitD [25(OH)D] and used the 98.2 item Block Brief 2000 Food Frequency Questionnaires to measure dietary intake of quercetin and other nutrients. Case and control groups were compared using two-sample t test for continuous risk factors and Fisher exact test for categorical factors. Associations between risk factors and PCa risk were examined via age-adjusted logistic regression models. Results Interaction effects of dietary quercetin and serum vitD on PCa status were observed. AA men (age 40–70) with normal levels of serum vitD (> 30 ng/ml) had a 71% lower risk of PCa compared to AA men with vitD deficiency (OR=0.29, 95% CI: 0.08–1.03; p=0.055). In individuals with vitD deficiency, increased dietary quercetin showed a tendency toward lower risk of PCa (OR=0.91, 95% CI: 0.82–1.00; p=0.054, age-adjusted) while men with normal vitD were at elevated risk (OR=1.23, 95% CI: 1.04–1.45). Conclusions These findings suggest that AA men who are at a higher risk of PCa may benefit more from vitD intake, and supplementation with dietary quercetin may increase the risk of PCa in AA men with normal vitD levels. Further studies with larger populations are needed to better understand the impact of the interaction between sera vitD levels and supplementation with quercetin on PCa in AA men. PMID:26047130

  4. Pharmacokinetics of quercetin-loaded nanodroplets with ultrasound activation and their use for bioimaging

    PubMed Central

    Chang, Li-Wen; Hou, Mei-Ling; Hung, Shuo-Hui; Lin, Lie-Chwen; Tsai, Tung-Hu

    2015-01-01

    Bubble formulations have both diagnostic and therapeutic applications. However, research on nanobubbles/nanodroplets remains in the initial stages. In this study, a nanodroplet formulation was prepared and loaded with a novel class of chemotherapeutic drug, ie, quercetin, to observe its pharmacokinetic properties and ultrasonic bioimaging of specific sites, namely the abdominal vein and bladder. Four parallel groups were designed to investigate the effects of ultrasound and nanodroplets on the pharmacokinetics of quercetin. These groups were quercetin alone, quercetin triggered with ultrasound, quercetin-encapsulated in nanodroplets, and quercetin encapsulated in nanodroplets triggered with ultrasound. Spherical vesicles with a mean diameter of 280 nm were formed, and quercetin was completely encapsulated within. In vivo ultrasonic imaging confirmed that the nanodroplets could be treated by ultrasound. The results indicate that the initial 5-minute serum concentration, area under the concentration–time curve, elimination half-life, and clearance of quercetin were significantly enhanced by nanodroplets with or without ultrasound. PMID:25945049

  5. Design of PLGA-functionalized quercetin nanoparticles for potential use in Alzheimer's disease.

    PubMed

    Sun, Dongdong; Li, Nuan; Zhang, Weiwei; Zhao, Zhiwei; Mou, Zhipeng; Huang, Donghui; Liu, Jie; Wang, Weiyun

    2016-12-01

    Dysfunctional interaction of amyloid-β (Aβ) with excess metal ions is proved to be related to the etiology of Alzheimer's disease (AD). Hence, disruption of these metal-peptide interactions using nanoparticles (NPs) holds considerable promise as a therapeutic strategy to combat this incurable disease. Given that quercetin is a natural product, the biocompatibility and small size essential for permeating the blood-brain barrier make it a potential therapeutic drug candidate for treating AD. Nanocarriers formulated with the US Food and Drug Administration-approved biocompatible and biodegradable polymer PLGA are being widely explored for the controlled delivery of therapeutic drugs, proteins, peptides, oligonucleotides, and genes. With this background, the present study was undertaken to investigate the effects of PLGA-functionalized quercetin (PLGA@QT) NPs on inhibited and disassembled Aβ42 fibrils and the PLGA@QT NPs have low cytotoxicity when tested on SH-SY5Y cells in vitro. As expected, the cytotoxicity studies of the PLGA@QT NPs led to a concentration-related behaviour on the SH-SY5Y human neuroblastoma cells. And, it has demonstrated that PLGA@QT NPs can inhibit the neurotoxicity of Zn(2+)-Aβ42 system and enhance the viability of neuron cells. The results from behavioral tests indicate that injection of PLGA@QT NPs into APP/PS1 mice ameliorate cognition and memory impairments. Most encouragingly, the in vivo systemic toxicity of PLGA@QT NPs examined by histological analysis in major organs did not show any signs of adverse effect to mice. Thus, the prepared quercetin based nanoscale drug delivery carrier efficiently enhanced the therapeutic index and reduced the side effects. Our findings are highly encouraging, providing substantial evidence of the safety of PLGA@QT NPs for biomedical application. We expect these findings will be relevant for other NPs for treatment of AD and have broad implications in NP-based studies and applications.

  6. Enzymatic modification of chitosan with quercetin and its application as antioxidant edible films.

    PubMed

    Torres, E; Marín, V; Aburto, J; Beltrán, H I; Shirai, K; Villanueva, S; Sandoval, G

    2012-01-01

    Quercetin, rutin, naringin, hesperidin and chrysin were tested as substrates for chloroperoxidase to produce reactive quinones to graft onto chitosan. Quercetin and rutin quinones were successfully chemically attached to low molecular weight chitosan. The quercetin-modified chitosan showed an enhancement of plastic, antioxidant and antimicrobial properties as well as of thermal degradability. Finally, chitosan-quercetin films visibly decreased enzymatic oxidation when applied to Opuntia ficus indica cladodes.

  7. Synthesis, Characterization and Cytotoxicity of Alkylated Quercetin Derivatives

    PubMed Central

    Bao, Xin-Ran; Liao, Han; Qu, Jiao; Sun, Yong; Guo, Xin; Wang, En-Xia; Zhen, Yu-Hong

    2016-01-01

    Quercetin, a ubiquitous flavonol, represents a promising leading drug for development of new chemotherapeutic agents. However, its limited cytotoxicity to cancer cells hampers its clinical use. In order to obtain novel quercetin derivatives with superior cytotoxicity, seven alkylated quercetin derivatives were synthesized. Solubility of these derivatives was determined by turbidimetry. Cytotoxicity of the high-soluble derivatives against MCF-7 cells and caco-2 cells was determined using MTT assay. Among these seven products, 7-O-butylquercetin had the highest solubility in DMEM medium and 7-O-geranylquercetin had the most potent cytotoxicity. Further study on cytotoxicity of 7-O-geranylquercetin on NCI-H446, A549, MGC-803 and SGC-7901 cell lines revealed potential antiproliferative effects. The 7-O-geranylquercetin is a broad spectrum cytotoxic agent and it may be a promising leading drug for cancer chemotherapy. PMID:27980567

  8. Quercetin as natural stabilizing agent for bio-polymer

    SciTech Connect

    Morici, Elisabetta; Arrigo, Rossella; Dintcheva, Nadka Tzankova

    2014-05-15

    The introduction of antioxidants in polymers is the main way to prevent or delay the degradation process. In particular natural antioxidants receive attention in the food industry also because of their presumed safety. In this work bio-polymers, i.e. a commercial starch-based polymer (Mater-Bi®) and a bio-polyester (PLA), and a bio-polyether (PEO) were additivated with quercetin, a natural flavonoid antioxidants, in order to formulate bio-based films for ecosustainable packaging and outdoor applications. The photo-oxidation behavior of unstabilized and quercetin stabilized films was analyzed and compared with the behavior of films additivated with a commercial synthetic light stabilizer. The quercetin is able to slow down the photo-degradation rate of all bio-polymeric films investigated in similar way to the synthetic stabilizer.

  9. Quercetin as natural stabilizing agent for bio-polymer

    NASA Astrophysics Data System (ADS)

    Morici, Elisabetta; Arrigo, Rossella; Dintcheva, Nadka Tzankova

    2014-05-01

    The introduction of antioxidants in polymers is the main way to prevent or delay the degradation process. In particular natural antioxidants receive attention in the food industry also because of their presumed safety. In this work bio-polymers, i.e. a commercial starch-based polymer (Mater-Bi®) and a bio-polyester (PLA), and a bio-polyether (PEO) were additivated with quercetin, a natural flavonoid antioxidants, in order to formulate bio-based films for ecosustainable packaging and outdoor applications. The photo-oxidation behavior of unstabilized and quercetin stabilized films was analyzed and compared with the behavior of films additivated with a commercial synthetic light stabilizer. The quercetin is able to slow down the photo-degradation rate of all bio-polymeric films investigated in similar way to the synthetic stabilizer.

  10. [Hypoglycemic and hypolipidemic effects of quercetin and its glycosides].

    PubMed

    Yan, Shu-xia; Li, Xian; Sun, Chong-de; Chen, Kun-song

    2015-12-01

    Quercetin and its glycosides are important flavonols in traditional herbal drugs and plant-derived food, and they have diverse hiological activities such as antioxidant, anticarcinogenic, anti-inflammatory, hypoglycemic and hypolipidemic activities. Numerous studies have demonstrated that quercetin and its glycosides were effective in the prevention and treatment of non-infectious chronic disease such as diabetes, obesity, and hyperlipidemia. They can regulate glucose and lipid metaholism through different mechanisms. They can decrease blood glucose via protecting pancreatic/p cells or/and improving insulin sensitivity. Also, they have lipid-lowering effects, which may be the result of regulation of lipid catabolism or/and anabolism. Their distributions, as well as the hypoglycemic and hypolipidemic effects are reviewed in this paper. In addition, further bioactivities as well as their dose-activity relationship, structure-activity relationship, bioavailability, and future clinical application of quercetin and its glycosides are discussed and proposed.

  11. Synthesis, Characterization and Cytotoxicity of Alkylated Quercetin Derivatives.

    PubMed

    Bao, Xin-Ran; Liao, Han; Qu, Jiao; Sun, Yong; Guo, Xin; Wang, En-Xia; Zhen, Yu-Hong

    2016-01-01

    Quercetin, a ubiquitous flavonol, represents a promising leading drug for development of new chemotherapeutic agents. However, its limited cytotoxicity to cancer cells hampers its clinical use. In order to obtain novel quercetin derivatives with superior cytotoxicity, seven alkylated quercetin derivatives were synthesized. Solubility of these derivatives was determined by turbidimetry. Cytotoxicity of the high-soluble derivatives against MCF-7 cells and caco-2 cells was determined using MTT assay. Among these seven products, 7-O-butylquercetin had the highest solubility in DMEM medium and 7-O-geranylquercetin had the most potent cytotoxicity. Further study on cytotoxicity of 7-O-geranylquercetin on NCI-H446, A549, MGC-803 and SGC-7901 cell lines revealed potential antiproliferative effects. The 7-O-geranylquercetin is a broad spectrum cytotoxic agent and it may be a promising leading drug for cancer chemotherapy.

  12. Rational design and structure-activity relationship studies of quercetin-amino acid hybrids targeting the anti-apoptotic protein Bcl-xL.

    PubMed

    Kellici, Tahsin F; Chatziathanasiadou, Maria V; Lee, Min-Sung; Sayyad, Nisar; Geromichalou, Elena G; Vrettos, Eirinaios I; Tsiailanis, Antonis D; Chi, Seung-Wook; Geromichalos, George D; Mavromoustakos, Thomas; Tzakos, Andreas G

    2017-09-26

    Anti-apoptotic proteins, like the Bcl-2 family proteins, present an important therapeutic cancer drug target. Their activity is orchestrated through neutralization upon interaction of pro-apoptotic protein counterparts that leads to immortality of cancer cells. Therefore, generating compounds targeting these proteins is of immense therapeutic importance. Herein, Induced Fit Docking (IFD) and Molecular Dynamics (MD) simulations were performed to rationally design quercetin analogues that bind in the BH3 site of the Bcl-xL protein. IFD calculations determined their binding cavity while Molecular Mechanics Poisson Boltzmann Surface Area (MM-PBSA) and Molecular Mechanics Generalised Born Surface Area (MM-GBSA) calculations provided an insight into the binding enthalpies of the analogues. The quercetin analogues were synthesized and their binding to Bcl-xL was verified with fluorescence spectroscopy. The binding affinity and the thermodynamic parameters between Bcl-xL and quercetin-glutamic acid were estimated through Isothermal Titration Calorimetry. 2D (1)H-(15)N HSQC NMR chemical shift perturbation mapping was used to chart the binding site of the quercetin analogues in the Bcl-xL that overlapped with the predicted poses generated by both IFD and MD calculations. Furthermore, evaluation of the four conjugates against the prostate DU-145 and PC-3 cancer cell lines, revealed quercetin-glutamic acid and quercetin-alanine as the most potent conjugates bearing the higher cytostatic activity. This pinpoints that the chemical space of natural products can be tailored to exploit new hits for difficult tractable targets such as protein-protein interactions.

  13. Quercetin Suppresses Twist to Induce Apoptosis in MCF-7 Breast Cancer Cells

    PubMed Central

    Ranganathan, Santhalakshmi; Halagowder, Devaraj; Sivasithambaram, Niranjali Devaraj

    2015-01-01

    Quercetin is a dietary flavonoid which exerts anti-oxidant, anti-inflammatory and anti-cancer properties. In this study, we investigated the anti-proliferative effect of quercetin in two breast cancer cell lines (MCF-7 and MDA-MB-231), which differed in hormone receptor. IC50 value (37μM) of quercetin showed significant cytotoxicity in MCF-7 cells, which was not observed in MDA-MB-231 cells even at 100μM of quercetin treatment. To study the response of cancer cells to quercetin, with respect to different hormone receptors, both the cell lines were treated with a fixed concentration (40μM) of quercetin. MCF-7 cells on quercetin treatment showed more apoptotic cells with G1 phase arrest. In addition, quercetin effectively suppressed the expression of CyclinD1, p21, Twist and phospho p38MAPK, which was not observed in MDA-MB-231 cells. To analyse the molecular mechanism of quercetin in exerting an apoptotic effect in MCF-7 cells, Twist was over-expressed and the molecular changes were observed after quercetin administration. Quercetin effectively regulated the expression of Twist, in turn p16 and p21 which induced apoptosis in MCF-7 cells. In conclusion, quercetin induces apoptosis in breast cancer cells through suppression of Twist via p38MAPK pathway. PMID:26491966

  14. Estimated Daily Intake and Seasonal Food Sources of Quercetin in Japan

    PubMed Central

    Nishimuro, Haruno; Ohnishi, Hirofumi; Sato, Midori; Ohnishi-Kameyama, Mayumi; Matsunaga, Izumi; Naito, Shigehiro; Ippoushi, Katsunari; Oike, Hideaki; Nagata, Tadahiro; Akasaka, Hiroshi; Saitoh, Shigeyuki; Shimamoto, Kazuaki; Kobori, Masuko

    2015-01-01

    Quercetin is a promising food component, which can prevent lifestyle related diseases. To understand the dietary intake of quercetin in the subjects of a population-based cohort study and in the Japanese population, we first determined the quercetin content in foods available in the market during June and July in or near a town in Hokkaido, Japan. Red leaf lettuce, asparagus, and onions contained high amounts of quercetin derivatives. We then estimated the daily quercetin intake by 570 residents aged 20–92 years old in the town using a food frequency questionnaire (FFQ). The average and median quercetin intakes were 16.2 and 15.5 mg day−1, respectively. The quercetin intakes by men were lower than those by women; the quercetin intakes showed a low correlation with age in both men and women. The estimated quercetin intake was similar during summer and winter. Quercetin was mainly ingested from onions and green tea, both in summer and in winter. Vegetables, such as asparagus, green pepper, tomatoes, and red leaf lettuce, were good sources of quercetin in summer. Our results will help to elucidate the association between quercetin intake and risks of lifestyle-related diseases by further prospective cohort study and establish healthy dietary requirements with the consumption of more physiologically useful components from foods. PMID:25849945

  15. Variation of quercetin glycoside derivatives in three onion (Allium cepa L.) varieties.

    PubMed

    Kwak, Jung-Ho; Seo, Jeong Min; Kim, Na-Hyung; Arasu, Mariadhas Valan; Kim, Sunggil; Yoon, Moo Kyoung; Kim, Sun-Ju

    2017-09-01

    The aim of this study was to quantify the contents of individual quercetin glycosides in red, yellow and chartreuse onion by High Performance Liquid Chromatography (HPLC) analysis. Acid hydrolysis of individual quercetin glycosides using 6 M hydrochloric acid guided to identify and separate quercetin 7,4'-diglucoside, quercetin 3-glucoside, quercetin 4'-glucoside, and quercetin. The contents of total quercetin glycosides varied extensively among three varieties (ranged from 16.10 to 103.93 mg/g DW). Quercetin was the predominant compound that accounted mean 32.21 mg/g DW in red onion (43.6% of the total) and 127.92 mg/g DW in chartreuse onion (78.3% of the total) followed by quercetin 3-glucoside (28.83 and 24.16 mg/g DW) respectively. Quercetin 3-glucoside levels were much higher in yellow onion (43.85 mg/g DW) followed by quercetin 30.08 mg/g DW. Quercetin 4'-glucoside documented the lowest amount that documented mean 2.4% of the total glycosides. The varied contents of glycosides present in the different onion varieties were significant.

  16. Oral quercetin supplementation hampers skeletal muscle adaptations in response to exercise training.

    PubMed

    Casuso, R A; Martínez-López, E J; Nordsborg, N B; Hita-Contreras, F; Martínez-Romero, R; Cañuelo, A; Martínez-Amat, A

    2014-12-01

    We aimed to test exercise-induced adaptations on skeletal muscle when quercetin is supplemented. Four groups of rats were tested: quercetin sedentary, quercetin exercised, placebo sedentary, and placebo exercised. Treadmill exercise training took place 5 days a week for 6 weeks. Quercetin groups were supplemented with quercetin, via gavage, on alternate days throughout the experimental period. Sirtuin 1 (SIRT1), peroxisome proliferator-activated receptor γ coactivator-1α mRNA levels, mitochondrial DNA (mtDNA) content, and citrate synthase (CS) activity were measured on quadriceps muscle. Redox status was also quantified by measuring muscle antioxidant enzymatic activity and oxidative damage product, such as protein carbonyl content (PCC). Quercetin supplementation increased oxidative damage in both exercised and sedentary rats by inducing higher amounts of PCC (P < 0.001). Quercetin supplementation caused higher catalase (P < 0.001) and superoxide dismutase (P < 0.05) activity in the non-exercised animals, but not when quercetin is supplemented during exercise. Quercetin supplementation increased SIRT1 expression, but when quercetin is supplemented during exercise, this effect is abolished (P < 0.001). The combination of exercise and quercetin supplementation caused lower (P < 0.05) mtDNA content and CS activity when compared with exercise alone. Quercetin supplementation during exercise provides a disadvantage to exercise-induced muscle adaptations.

  17. Quercetin Suppresses Twist to Induce Apoptosis in MCF-7 Breast Cancer Cells.

    PubMed

    Ranganathan, Santhalakshmi; Halagowder, Devaraj; Sivasithambaram, Niranjali Devaraj

    2015-01-01

    Quercetin is a dietary flavonoid which exerts anti-oxidant, anti-inflammatory and anti-cancer properties. In this study, we investigated the anti-proliferative effect of quercetin in two breast cancer cell lines (MCF-7 and MDA-MB-231), which differed in hormone receptor. IC50 value (37μM) of quercetin showed significant cytotoxicity in MCF-7 cells, which was not observed in MDA-MB-231 cells even at 100μM of quercetin treatment. To study the response of cancer cells to quercetin, with respect to different hormone receptors, both the cell lines were treated with a fixed concentration (40μM) of quercetin. MCF-7 cells on quercetin treatment showed more apoptotic cells with G1 phase arrest. In addition, quercetin effectively suppressed the expression of CyclinD1, p21, Twist and phospho p38MAPK, which was not observed in MDA-MB-231 cells. To analyse the molecular mechanism of quercetin in exerting an apoptotic effect in MCF-7 cells, Twist was over-expressed and the molecular changes were observed after quercetin administration. Quercetin effectively regulated the expression of Twist, in turn p16 and p21 which induced apoptosis in MCF-7 cells. In conclusion, quercetin induces apoptosis in breast cancer cells through suppression of Twist via p38MAPK pathway.

  18. Neuroprotective effects of quercetin in diabetic rat retina.

    PubMed

    Ola, Mohammad S; Ahmed, M M; Shams, Shakeeb; Al-Rejaie, Salim S

    2017-09-01

    Diabetic retinopathy (DR) is a severe complication of diabetes and the leading cause of blindness among working adults worldwide. DR is being widely recognized as a neurodegenerative disease of the retina, since, retinal neurons are damaged soon after diabetes onset. Diabetes-induced oxidative stress is considered as central factor that dysregulates neurotrophic factors and activates apoptosis, thereby damages neurons in the diabetic retina. Flavonoids being a powerful antioxidant have been considered to protect neurons in diabetic retina. The purpose of this study was to analyze the beneficial effects of flavonoid, quercetin to protect neurons in the diabetic rat retina. We quantitated the expression levels of BDNF, NGF, TrkB, synaptophysin, Akt, Bcl-2, cytochrome c and caspase-3 using Western blotting techniques in the diabetic retina with and without quercetin treatments and compared with non-diabetic rats. In addition, we employed ELISA techniques to determine the level of BDNF. Caspase-3 activity and the level of glutathione were analyzed by biochemical methods. Our results indicate that quercetin treatment to diabetic rats caused a significant increase in the level of neurotrophic factors and inhibited the level of cytochrome c and caspase-3 activity in the diabetic retina. Furthermore, the level of an anti-apoptotic protein Bcl-2 was augmented in quercetin treated diabetic retina. Thus, quercetin, may protect the neuronal damage in diabetic retina by ameliorating the levels of neurotrophic factors and also by inhibiting the apoptosis of neurons. Therefore, this study suggests that quercetin can be a suitable therapeutic agent to prevent neurodegeneration in diabetic retinopathy.

  19. [Quercetin induces the apoptosis of human PC-3 cells].

    PubMed

    Zhu, Qing-Yi; Hu, Rui; Liu, Li; Yuan, Lin; Huang, Wei-Zhou; Ma, Long; Gu, Xiao-Jian

    2011-09-01

    To study the effect of quercetin on the apoptosis of human PC-3 cells. Human PC-3 cells were cultured in vitro and then treated with quercetin at the concentrations of 50, 100, 150, 200 and 250 micromol/L. The inhibition rate of quercetin on the PC-3 cells was detected by MTT, the apoptosis of the cells determined by flow cytometry, and the changes of the cellular ultramicrostructure observed by transmission electron microscopy. Quercetin markedly inhibited the proliferation of PC-3 cells in vitro in a time- and dose-dependent manner. Its inhibition rates were (3.01 +/- 1.32)%, (4.84 +/- 1.73)%, (20.35 +/- 1.30)%, (16.78 +/- 1.89)% and (27.25 +/- 4.01)% at 24 hours, and (10.18 +/- 1.16)%, (6.22 +/- 0.04)%, (24.29 +/- 4.19)%, (22.4 +/- 4.26)% and (41.42 +/- 5.43)% at 48 hours in the 50, 100, 150, 200 and 250 micromol/L groups, respectively, with statistical significance at the concentration of > 150 micromol/L (P < 0.05). Flow cytometry showed that the apoptosis of PC-3 cells was increased with the elevated concentration and prolonged time of Quercetin treatment, (19.10 +/- 0.28)% and (26.55 +/- 0.78)% at 24 hours, and (27.65 +/- 1.06)% and (38.30 +/- 5.96)% at 48 hours in the 150 and 200 micromol/L groups, respectively (P < 0.05). Typical changes in the morphology of the cells were observed under the transmission electron microscope. Quercetin can inhibit the proliferation and induce the apoptosis of human PC-3 cells, but its action mechanism remains to be further investigated.

  20. Quercetin increases brain and muscle mitochondrial biogenesis and exercise tolerance.

    PubMed

    Davis, J Mark; Murphy, E Angela; Carmichael, Martin D; Davis, Ben

    2009-04-01

    Quercetin is one of a broad group of natural polyphenolic flavonoid substances that are being investigated for their widespread health benefits. These benefits have generally been ascribed to its combination of antioxidant and anti-inflammatory activity, but recent in vitro evidence suggests that improved mitochondrial biogenesis could play an important role. In addition, the in vivo effects of quercetin on mitochondrial biogenesis exercise tolerance are unknown. We examined the effects of 7 days of quercetin feedings in mice on markers of mitochondrial biogenesis in skeletal muscle and brain, and on endurance exercise tolerance. Mice were randomly assigned to one of the following three treatment groups: placebo, 12.5 mg/kg quercetin, or 25 mg/kg quercetin. Following 7 days of treatment, mice were killed, and soleus muscle and brain were analyzed for mRNA expression of peroxisome proliferator-activated receptor-gamma coactivator (PGC-1alpha) and sirtuin 1 (SIRT1), and mitochondrial DNA (mtDNA) and cytochrome c. Additional mice underwent a treadmill performance run to fatigue or were placed in voluntary activity wheel cages, and their voluntary activity (distance, time, and peak speed) was recorded. Quercetin increased mRNA expression of PGC-1alpha and SIRT1 (P < 0.05), mtDNA (P < 0.05) and cytochrome c concentration (P < 0.05). These changes in markers of mitochondrial biogenesis were associated with an increase in both maximal endurance capacity (P < 0.05) and voluntary wheel-running activity (P < 0.05). These benefits of querectin on fitness without exercise training may have important implications for enhancement of athletic and military performance and may also extend to prevention and/or treatment of chronic diseases.

  1. Microbial transformation of quercetin and its prenylated derivatives.

    PubMed

    Xiao, Yina; Lee, Ik-Soo

    2017-08-22

    The microbial transformation studies of 7-O-prenylquercetin (1), 4'-O-prenylquercetin (2) and quercetin (3) were investigated with 20 different microbial strains to discover new metabolites. It was revealed that the fungus Mucor hiemalis was the most appropriate micro-organism which was capable of transforming these flavonoids. Structures of the three new (4-6) and one known (7) metabolites were elucidated as 7-O-prenylquercetin 3-O-β-D-glucopyranoside (4), 4'-O-prenylquercetin 3-O-β-D-glucopyranoside (5), 4'-O-prenylquercetin 3'-O-β-D-glucopyranoside (6) and quercetin 5-O-β-D-glucopyranoside (7) by the spectroscopic methods.

  2. Production of 3-O-xylosyl quercetin in Escherichia coli.

    PubMed

    Pandey, Ramesh Prasad; Malla, Sailesh; Simkhada, Dinesh; Kim, Byung-Gee; Sohng, Jae Kyung

    2013-03-01

    Quercetin, a flavonol aglycone, is one of the most abundant flavonoids with high medicinal value. The bioavailability and pharmacokinetic properties of quercetin are influenced by the type of sugars attached to the molecule. To efficiently diversify the therapeutic uses of quercetin, Escherichia coli was harnessed as a production factory by the installation of various plant and bacterial UDP-xylose sugar biosynthetic genes. The genes encoding for the UDP-xylose pathway enzymes phosphoglucomutase (nfa44530), glucose-1-phosphate uridylyltransferase (galU), UDP-glucose dehydrogenase (calS8), and UDP-glucuronic acid decarboxylase (calS9) were overexpressed in E. coli BL21 (DE3) along with a glycosyltransferase (arGt-3) from Arabidopsis thaliana. Furthermore, E. coli BL21(DE3)/∆pgi, E. coli BL21(DE3)/∆zwf, E. coli BL21(DE3)/∆pgi∆zwf, and E. coli BL21(DE3)/∆pgi∆zwf∆ushA mutants carrying the aforementioned UDP-xylose sugar biosynthetic genes and glycosyltransferase and the galU-integrated E. coli BL21(DE3)/∆pgi host harboring only calS8, calS9, and arGt-3 were constructed to enhance whole-cell bioconversion of exogeneously supplied quercetin into 3-O-xylosyl quercetin. Here, we report the highest production of 3-O-xylosyl quercetin with E. coli BL21 (DE3)/∆pgi∆zwf∆ushA carrying UDP-xylose sugar biosynthetic genes and glycosyltransferase. The maximum concentration of 3-O-xylosyl quercetin achieved was 23.78 mg/L (54.75 μM), representing 54.75 % bioconversion, which was an ~4.8-fold higher bioconversion than that shown by E. coli BL21 (DE3) with the same set of genes when the reaction was carried out in 5-mL culture tubes with 100 μM quercetin under optimized conditions. Bioconversion was further improved by 98 % when the reaction was scaled up in a 3-L fermentor at 36 h.

  3. Optimization of β-cyclodextrin cross-linked polymer for monitoring of quercetin.

    PubMed

    Zhu, Xiashi; Ping, Wenhui

    2014-11-11

    A novel method for the separation/analysis of quercetin was described, which was based on the investigation of the inclusion interactions of β-cyclodextrin cross-linked polymer (β-CDCP) with quercetin (Qu) and the adsorption behavior of Qu on β-CDCP. The inclusion interaction of β-CDCP with Qu was studied through FTIR, TGA and 13C NMR. Under the optimum conditions, the preconcentration factor of the proposed method was approximately 8.8, the β-CDCP could be used repeatedly for 30 times and offered better recovery. The linear range, limit of detection (LOD) and the relative standard deviation (RSD) was found to be 0.10-12.0 μg mL(-1), 4.6 ng mL(-1) and 3.10% (n=3, c=2.0 μg mL(-1)) respectively. This technique had been successfully applied to the determination of Qu in real samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Optimization of β-cyclodextrin cross-linked polymer for monitoring of quercetin

    NASA Astrophysics Data System (ADS)

    Zhu, Xiashi; Ping, Wenhui

    2014-11-01

    A novel method for the separation/analysis of quercetin was described, which was based on the investigation of the inclusion interactions of β-cyclodextrin cross-linked polymer (β-CDCP) with quercetin (Qu) and the adsorption behavior of Qu on β-CDCP. The inclusion interaction of β-CDCP with Qu was studied through FTIR, TGA and 13C NMR. Under the optimum conditions, the preconcentration factor of the proposed method was approximately 8.8, the β-CDCP could be used repeatedly for 30 times and offered better recovery. The linear range, limit of detection (LOD) and the relative standard deviation (RSD) was found to be 0.10-12.0 μg mL-1, 4.6 ng mL-1 and 3.10% (n = 3, c = 2.0 μg mL-1) respectively. This technique had been successfully applied to the determination of Qu in real samples.

  5. Preparation, characterization, and DNA binding studies of water-soluble quercetin--molybdenum(VI) complex.

    PubMed

    Ahmadi, Seyed Mojtaba; Dehghan, Gholamreza; Hosseinpourfeizi, Muhammad Ali; Dolatabadi, Jafar Ezzati Nazhad; Kashanian, Soheila

    2011-07-01

    DNA binding studies of flavonoids are needed to understand the reaction mechanism and improve drugs that target DNA. Quercetin (Q) is one of the most common flavonoids that can chelate metal ions and interact with double-stranded DNA. In the present work, UV absorption spectrophotometry, viscosimetry, circular dichroism, and fluorescence spectroscopic techniques were employed to study the interaction of water-soluble quercetin--molybdenum(VI) complex [Q-Mo(VI)] with calf thymus DNA. The binding constants (K(b)) for the complex with DNA were estimated to be 2.9 × 10(3) through spectroscopic titrations. Upon addition of the complex, significant decreases were observed in the viscosity of calf thymus DNA. Circular dichroic spectra indicated that there are certain detectable conformational changes in the DNA double helix when complex was added. Further, competitive methylene blue binding studies with fluorescence spectroscopy have shown that the complex can bind to DNA through nonintercalative mode. The experimental results suggest that Q-Mo(VI) binds to DNA via an outside binding mode.

  6. Intracellular metabolism and bioactivity of quercetin and its in vivo metabolites.

    PubMed Central

    Spencer, Jeremy P E; Kuhnle, Gunter G C; Williams, Robert J; Rice-Evans, Catherine

    2003-01-01

    Understanding the cellular effects of flavonoid metabolites is important for predicting which dietary flavonoids might be most beneficial in vivo. Here we investigate the bioactivity in dermal fibroblasts of the major reported in vivo metabolites of quercetin, i.e. 3'-O-methyl quercetin, 4'-O-methyl quercetin and quercetin 7-O-beta-D-glucuronide, relative to that of quercetin, in terms of their further metabolism and their resulting cytotoxic and/or cytoprotective effects in the absence and presence of oxidative stress. Uptake experiments indicate that exposure to quercetin led to the generation of two novel cellular metabolites, one characterized as a 2'-glutathionyl quercetin conjugate and another product with similar spectral characteristics but 1 mass unit lower, putatively a quinone/quinone methide. A similar product was identified in cells exposed to 3'-O-methyl quercetin, but not in the lysates of those exposed to its 4'-O-methyl counterpart, suggesting that its formation is related to oxidative metabolism. There was no uptake or metabolism of quercetin 7-O-beta-D-glucuronide by fibroblasts. Formation of oxidative metabolites may explain the observed concentration-dependent toxicity of quercetin and 3'-O-methyl quercetin, whereas the formation of a 2'-glutathionyl quercetin conjugate is interpreted as a detoxification step. Both O -methylated metabolites conferred less protection than quercetin against peroxide-induced damage, and quercetin glucuronide was ineffective. The ability to modulate cellular toxicity paralleled the ability of the compounds to decrease the level of peroxide-induced caspase-3 activation. Our data suggest that the actions of quercetin and its metabolites in vivo are mediated by intracellular metabolites. PMID:12578560

  7. Quercetin stimulates mitochondrial apoptosis dependent on activation of endoplasmic reticulum stress in hepatic stellate cells.

    PubMed

    He, Liwei; Hou, Xianbang; Fan, Fangtian; Wu, Hongyan

    2016-12-01

    Activation of hepatic stellate cells (HSCs) is a hallmark of liver fibrosis. Quercetin has benefits for liver fibrosis, but the mechanisms are unknown. We investigated the quercetin effect on HSC survival and the role of endoplasmic reticulum stress (ERS). Rat HSCs and LO2 hepatocytes were treated with quercetin (0.5-120 μM) for 24 h. Quercetin (10-40 μM) effects on apoptosis for 24 h were analyzed by flow cytometry and TUNEL staining. Quercetin (10-40 μM) effects on the expression of Bcl-2, caspase-9, caspase-3, PARP-1, PERK, IRE1, ATF6, calnexin and CHOP for 24 h were analyzed by Western blot. Quercetin (10-40 μM) effects on mRNA expression of calnexin and CHOP for 24 h were analyzed by Real-time PCR. Quercetin at concentrations greater than 20 μM significantly inhibited HSC proliferation (IC50 27.2 μM), but did not affect hepatocyte growth until 80 μM (IC50 68.5 μM). Quercetin stimulated HSC apoptosis and the apoptotic rate reached 40% at a concentration of 40 μM (EC50 51.6 μM). Quercetin induced downregulation of Bcl-2 and upregulation of Bax, and increased cytochrome C in the cytoplasm in HSCs. The cleaved forms of caspase-9, caspase-3 and PARP-1 were also increased by quercetin. Furthermore, quercetin elevated mRNA and protein expression of calnexin and CHOP in HSCs but not in hepatocytes. Quercetin also increased phosphorylation of PERK and IRE1 and ATF6 cleavage. However, ERS inhibitor salubrinal significantly abrogated quercetin induction of HSC apoptosis. Quercetin activated ERS pathway in HSCs leading to apoptosis. We characterized an ERS-mediated mechanism for quercetin as a promising antifibrotic agent.

  8. Molecular targets of quercetin with anti-inflammatory properties in atopic dermatitis.

    PubMed

    Karuppagounder, Vengadeshprabhu; Arumugam, Somasundaram; Thandavarayan, Rajarajan A; Sreedhar, Remya; Giridharan, Vijayasree V; Watanabe, Kenichi

    2016-04-01

    Atopic dermatitis (AD) is an inflammatory skin disease. Over the past few decades, AD has become more prevalent worldwide. Quercetin, a naturally occurring polyphenol, shows antioxidant, anti-inflammatory, and antiallergic activities. Several recent clinical and preclinical findings suggest quercetin as a promising natural treatment for inflammatory skin diseases. Significant progress in elucidating the molecular mechanisms underlying the anti-AD properties of quercetin has been achieved in the recent years. Here, we discuss the use of quercetin as treatment for AD, with a particular focus on the molecular basis of its effect. We also briefly discuss the approaches to improve the bioavailability of quercetin.

  9. Quercetin inhibits AMPK/TXNIP activation and reduces inflammatory lesions to improve insulin signaling defect in the hypothalamus of high fructose-fed rats.

    PubMed

    Zhang, Qing-Yu; Pan, Ying; Wang, Rong; Kang, Lin-Lin; Xue, Qiao-Chu; Wang, Xiao-Ning; Kong, Ling-Dong

    2014-04-01

    Fructose is a nutritional composition of fruits and honey. Its excess consumption induces insulin resistance-associated metabolic diseases. Hypothalamic insulin signaling plays a pivotal role in controlling whole-body insulin sensitivity and energy homeostasis. Quercetin, a natural flavonoid, has been reported to ameliorate high fructose-induced rat insulin resistance and hyperlipidemia. In this study, we investigated its regulatory effects on the hypothalamus of high fructose-fed rats. Rats were fed 10% fructose in drinking water for 10 weeks. After 4 weeks, these animals were orally treated with quercetin (50 and 100 mg/kg), allopurinol (5 mg/kg) and water daily for the next 6 weeks, respectively. Quercetin effectively restored high fructose-induced hypothalamic insulin signaling defect by up-regulating the phosphorylation of insulin receptor and protein kinase B. Furthermore, quercetin was found to reduce metabolic nutrient sensors adenosine monophosphate-activated protein kinase (AMPK) activation and thioredoxin-interacting protein (TXNIP) overexpression, as well as the glutamine-glutamate cycle dysfunction in the hypothalamus of high fructose-fed rats. Subsequently, it ameliorated high fructose-caused hypothalamic inflammatory lesions in rats by suppressing the activation of hypothalamic nuclear factor κB (NF-κB) pathway and NOD-like receptor 3 (NLRP3) inflammasome with interleukin 1β maturation. Allopurinol had similar effects. These results provide in vivo evidence that quercetin-mediated down-regulation of AMPK/TXNIP and subsequent inhibition of NF-κB pathway/NLRP3 inflammasome activation in the hypothalamus of rats may be associated with the reduction of hypothalamic inflammatory lesions, contributing to the improvement of hypothalamic insulin signaling defect in this model. Thus, quercetin with the central activity may be a therapeutic for high fructose-induced insulin resistance and hyperlipidemia in humans.

  10. Effect of quercetin and its metabolites isorhamnetin and quercetin-3-glucuronide on inflammatory gene expression: role of miR-155.

    PubMed

    Boesch-Saadatmandi, Christine; Loboda, Agnieszka; Wagner, Anika E; Stachurska, Anna; Jozkowicz, Alicja; Dulak, Jozef; Döring, Frank; Wolffram, Siegfried; Rimbach, Gerald

    2011-03-01

    In the present study the effect of quercetin and its major metabolites quercetin-3-glucuronide (Q3G) and isorhamnetin on inflammatory gene expression was determined in murine RAW264.7 macrophages stimulated with lipopolysaccharide. Quercetin and isorhamnetin but not Q3G significantly decreased mRNA and protein levels of tumor necrosis factor alpha. Furthermore a significant decrease in mRNA levels of interleukin 1β, interleukin 6, macrophage inflammatory protein 1α and inducible nitric oxide synthase was evident in response to the quercetin treatment. However Q3G did not affect inflammatory gene expression. Anti-inflammatory properties of quercetin and isorhamnetin were accompanied by an increase in heme oxygenase 1 protein levels, a downstream target of the transcription factor Nrf2, known to antagonize chronic inflammation. Furthermore, proinflammatory microRNA-155 was down-regulated by quercetin and isorhamnetin but not by Q3G. Finally, anti-inflammatory properties of quercetin were confirmed in vivo in mice fed quercetin-enriched diets (0.1 mg quercetin/g diet) over 6 weeks.

  11. The flavonoid quercetin inhibits pancreatic cancer growth in vitro and in vivo

    PubMed Central

    Angst, Eliane; Park, Jenny L.; Moro, Aune; Lu, Qing-Yi; Lu, Xuyang; Li, Gang; King, Jonathan; Chen, Monica; Reber, Howard A.; Go, Vay Liang W.; Eibl, Guido; Hines, Oscar J.

    2012-01-01

    Objectives The flavonoid quercetin holds promise as an anti-tumor agent in several preclinical animal models. However, the efficacy of oral administration of quercetin in a pancreatic cancer mouse model is unknown. Methods The anti-proliferative effects of quercetin alone or in combination with gemcitabine were tested in two human pancreatic cancer cell lines using cell count and MTT assays. Apoptosis was evaluated by flow cytometry. Tumor growth in vivo was investigated in an orthotopic pancreatic cancer animal model using bioluminescence. Quercetin was administered orally in the diet. Results Quercetin inhibited the growth of pancreatic cancer cell lines, which was caused by an induction of apoptosis. In addition, dietary supplementation of quercetin attenuated the growth of orthotopically transplanted pancreatic xenografts. The combination of gemcitabine and quercetin had no additional effect compared to quercetin alone. In vivo quercetin caused significant apoptosis and reduced tumor cell proliferation. Conclusions Our data provide evidence that oral administration of quercetin was capable of inhibiting growth of orthotopic pancreatic tumors in a nude mouse model. These data suggest a possible benefit of quercetin in patients with pancreatic cancer. PMID:23000892

  12. The flavonoid quercetin induces apoptosis and inhibits migration through a MAPK-dependent mechanism in osteoblasts.

    PubMed

    Nam, Tae Wook; Yoo, Chong Il; Kim, Hui Taek; Kwon, Chae Hwa; Park, Ji Yeon; Kim, Yong Keun

    2008-01-01

    The present study was undertaken to evaluate effects of quercetin, a major dietary flavonoid occurring in foods of plant origin, on cell viability and migration of osteoblastic cells. Quercetin inhibited cell viability, which was largely attributed to apoptosis, in a dose-and time-dependent manner in osteoblastic cells. Similar cytotoxicity of quercetin was observed in adipose tissue-derived stromal cells. Quercetin exerted a protective effect against H(2)O(2)-induced cell death, whereas it increased TNF-alpha-induced cell death. Western blot analysis showed that quercetin induced activation of ERK and p38, but not JNK. Quercetin-induced cell death was prevented by the ERK inhibitor PD98059, but not by inhibitors of p38 and JNK. Quercetin increased Bax expression and caused depolarization of mitochondrial membrane potential, which were inhibited by PD98059. Quercetin induced caspase-3 activation, and the quercetininduced cell death was prevented by caspase inhibitors. Quercetin inhibited cell migration, and its effect was prevented by inhibitors of ERK and p38. Taken together, these findings suggest that quercetin induces apoptosis through a mitochondria-dependent mechanism involving ERK activation and inhibits migration through activation of ERK and p38 pathways. Quercetin may exert both protective and deleterious effects in bone repair.

  13. Quercetin as colorimetric reagent for determination of zirconium

    USGS Publications Warehouse

    Grimaldi, F.S.; White, C.E.

    1953-01-01

    Methods described in the literature for the determination of zirconium are generally designed for relatively large amounts of this element. A good procedure using colorimetric reagent for the determination of trace amounts is desirable. Quercetin has been found to yield a sensitive color reaction with zirconium suitable for the determination of from 0.1 to 50?? of zirconium dioxide. The procedure developed involves the separation of zirconium from interfering elements by precipitation with p-dimethylaminoazophenylarsonic acid prior to its estimation with quercetin. The quercetin reaction is carried out in 0.5N hydrochloric acid solution. Under the operating conditions it is indicated that quercetin forms a 2 to 1 complex with zirconium; however, a 2 to 1 and a 1 to 1 complex can coexist under special conditions. Approximate values for the equilibrium constants of the complexes are K1 = 0.33 ?? 10-5 and K2 = 1.3 ?? 10-9. Seven Bureau of Standards samples of glass sands and refractories were analyzed with excellent results. The method described should find considerable application in the analysis of minerals and other materials for macro as well as micro amounts of zirconium.

  14. DFT study of glycosyl group reactivity in quercetin derivatives

    NASA Astrophysics Data System (ADS)

    Jeevitha, D.; Sadasivam, K.; Praveena, R.; Jayaprakasam, R.

    2016-09-01

    Density functional theory (DFT) is used to compute relevant electronic properties with the purpose of generating precise information which facilitates the best activity given by the positions of glycosyl group attached at all 3 different rings of quercetin such as Q3G (C- ring), Q7G (A-ring) and Q3‧G (B-ring). Computed values of the OH BDE, frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP), Density of states (DOS,PDOS,OPDOS) and electronic properties such as electron affinity (EA), ionization potential (IP), softness (S), hardness (η), electronegativity (χ) and electrophilic index (ω) indicate that the title compounds possess good radical scavenging activity. Charge delocalization and intramolecular hydrogen bonds are characterized using natural bond orbital (NBO) analysis. NBO accurately differentiate the weak and strong intramolecular hydrogen bond of quercetin-O-glycoside compounds. Results available from the computational investigation have proved that A-ring glycoside of quercetin is capable of donating electrons and acts as a good anti-oxidant than B-ring glycoside and C-ring glycoside of quercetin.

  15. Quercetin protects rat skeletal muscle from ischemia reperfusion injury.

    PubMed

    Ekinci Akdemir, Fazile Nur; Gülçin, İlhami; Karagöz, Berna; Soslu, Recep

    2016-01-01

    In this study, we investigated the potential beneficial effects of quercetin on skeletal muscle ischemia reperfusion injury. Twenty-four Sprague-Dawley type rats were randomly divided into four groups. In the sham group, only gastrocnemius muscle were removed and given no quercetin. In ischemia group, all the femoral artery, vein and collaterals were occluded in the left hindlimb by applying tourniquate under general anaesthesia for three hours but reperfusion was not done. In the Quercetin + Ischemia reperfusion group, quercetin (200 mg kg(-1) dose orally) was given during one-week reoperation and later ischemia reperfusion model was done. Finally, gastrocnemius muscle samples were removed to measure biochemical parameters. The biomarkers, MDA levels, SOD, CAT and GPx activities, were evaluated related to skeletal muscle ischemia reperfusion injury. MDA levels reduced and SOD, CAT and GPx activities increased significantly in Quercetin + Ischemia reperfusion group. Results clearly showed that Quercetin have a protective role against oxidative damage induced by ischemia reperfusion in rats.

  16. Characterization of adsorption and electronic excited states of quercetin on titanium dioxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Zdyb, Agata; Krawczyk, Stanisław

    2016-03-01

    Adsorption of quercetin on colloidal titanium dioxide nanoparticles in ethanol and its excited-state electronic structure were investigated by means of electronic and vibrational spectroscopies. The changes in electronic charge redistribution as reflected by the dipole moment difference, ∆μ, between the ground and excited electronic states were measured with electroabsorption spectroscopy and analyzed using results of TD DFT computations. Adsorption of quercetin causes a red shift of its absorption spectrum. Raman spectra of quercetin analyzed with reference to analogous data for morin indicate binding of quercetin through the hydroxy groups of the catechol moiety. The difference dipole moment, which is 5.5 D in free quercetin, increases to 11.8 D in opposite direction in adsorbed quercetin, and is associated with charge-transfer to the Ti atom. The computed transition energy, intensity, vector Δμ and molecular orbitals involved in the electronic transition at different molecular configurations indicate a bidentate chelating mode of binding of quercetin.

  17. Antioxidant study of quercetin and their metal complex and determination of stability constant by spectrophotometry method.

    PubMed

    Ravichandran, R; Rajendran, M; Devapiriam, D

    2014-03-01

    Quercetin found chelate cadmium ions, scavenge free radicals produced by cadmium. Hence new complex, quercetin with cadmium was synthesised, and the synthesised complex structures were determined by UV-vis spectrophotometry, infrared spectroscopy, thermogravimetry and differential thermal analysis techniques (UV-vis, IR, TGA and DTA). The equilibrium stability constants of quercetin-cadmium complex were determined by Job's method. The determined stability constant value of quercetin-cadminum complex at pH 4.4 is 2.27×10(6) and at pH 7.4 is 7.80×10(6). It was found that the quercetin and cadmium ion form 1:1 complex in both pH 4.4 and pH 7.4. The structure of the compounds was elucidated on the basis of obtained results. Furthermore, the antioxidant activity of the free quercetin and quercetin-cadmium complexes were determined by DPPH and ABTS assays.

  18. Maltodextrin fast dissolving films for quercetin nanocrystal delivery. A feasibility study.

    PubMed

    Lai, Francesco; Franceschini, Ilaria; Corrias, Francesco; Sala, Maria Chiara; Cilurzo, Francesco; Sinico, Chiara; Pini, Elena

    2015-05-05

    The objective of this study was to evaluate the feasibility to prepare fast dissolving films as quercetin nanocrystal delivery systems, using maltodextrins as film forming material and glycerin as plasticizer, with the goal of enhancing quercetin oral bioavailability. Quercetin nanosuspensions were prepared using a high-pressure homogenizer, and then directly used to prepare the films by a casting method. Spectroscopic and calorimetric analysis evidenced that reduction of quercetin size at nanoscale and incorporation in maltodextrin films do not affect the solid state of the active ingredient. The loading of quercetin nanocrystals into the film determined a slight variation of film elasticity and ductility. Indeed, the elastic modulus of the loaded films resulted about a half of the placebo ones, while the elongation at break increased four folds. Free and film loaded quercetin nanocrystals showed a comparable dissolution rate, much higher than that of bulk quercetin.

  19. Quercetin liposome sensitizes colon carcinoma to thermotherapy and thermochemotherapy in mice models.

    PubMed

    He, Bing; Wang, Xin; Shi, Hua-shan; Xiao, Wen-jing; Zhang, Jing; Mu, Bo; Mao, Yong-qiu; Wang, Wei; Wang, Yong-sheng

    2013-05-01

    Thermotherapy and thermochemotherapy have been used in clinics to treat patients with malignant diseases, including colon cancer, and their efficacy has been well proved. Heat shock proteins (HSPs), especially Hsp70, play important roles in neutralizing their efficacy. It has been reported that quercetin can suppress cancer by inhibiting the intratumoral expression of Hsp70. This study was designed to investigate whether quercetin could enhance sensitivity to thermotherapy and thermochemotherapy. Soluble quercetin liposome was used in this study. The effects of quercetin were investigated in vitro and in mouse colon cancer models of subcutaneous tumor and peritoneal carcinomatosis. The results showed that quercetin liposome inhibited the upregulation of Hsp70 and enhanced apoptosis induced by hyperthermia and thermochemotherapy. Systemic administration of quercetin liposome can sensitize CT26 cells to thermotherapy and chemothermotherapy. This study suggests that quercetin liposome might be potentially applied for clinical cancer therapy.

  20. Antihyperglycemic Effect of Quercetin in Ovariectomized Rats Treated with Tamoxifen.

    PubMed

    Silva, Fernanda Coleraus; Bramatti, Isabella Calvo; Toledo, Adrieli Gorlin; Salles, Fernando Marques; Itinose, Ana Maria; Marek, Carla Brugin

    2017-03-01

    Tamoxifen is effective in breast cancer therapy in postmenopausal women; however, it causes adverse effects that alter the glycolytic pathway and induce hyperglycemia. Quercetin, a flavonoid with antioxidant potential, inhibits butyrylcholinesterase (BuChE), which is positively associated with hyperglycemia. Therefore, this study investigated the effect of quercetin on tamoxifen-induced hyperglycemia, using BuChE activity as a bioindicator in adult ovariectomized Wistar rats. The ovariectomized rats were treated orally for 14 days with different concentrations of quercetin (2.5, 7.5, 22.5, and 67.5 mg.kg(-1) b.w.) and tamoxifen (5 mg.kg(-1) b.w.). Subsequently, they were euthanized; blood and tissue samples were collected. The following biochemical parameters were analyzed: plasma glucose levels and BuChE activity in the plasma, liver, intestine, and adipose tissue. The most effective dose of quercetin in reducing hyperglycemia was 22.5 mg.kg(-1) b.w. (Que/TAM 4.5/1, P < .00000), although the doses of 2.5 (Que/TAM 0.5/1, P < .05) and 7.5 mg.kg(-1) b.w. (Que/TAM 1.5/1, P < .05) were also effective. The BuChE activity decreased in the intestine at all tested doses of quercetin coadministered with tamoxifen (P < .01); however, in adipose tissue, there was a biphasic activity with a decrease (P < .05) and increase (P < .05) in activity at doses of 7.5 and 22.5 mg.kg(-1) b.w. of quercetin, respectively. However, the correlation between BuChE and glucose levels was not significant (P > .05). In summary, the findings of the present study suggest that quercetin when associated with tamoxifen decreases in plasma glucose levels. Furthermore, in these cases, BuChE should not be used as an indicator of hyperglycemia.

  1. Quercetin alleviates generalized hyperalgesia in mice with induced adenomyosis.

    PubMed

    Nie, Jichan; Liu, Xishi

    2017-10-01

    Adenomyosis is a common gynecologic disorder characterized by the presence of endometrial glands and stroma within the myometrium. The present study investigated the effect of quercetin in neonatal Imprinting Control Region mice with tamoxifen‑induced adenomyosis. The body weight and hotplate response latency of all mice was examined at 4, 8, 12 and 16 weeks after birth. The mice dosed with tamoxifen were divided into four groups: high‑ or low‑quercetin group, valproic acid (VPA) group and untreated group. The group of mice that were neonatally administrated with the solvent only (no tamoxifen), received no treatment and served as a blank control group. After 3 weeks of drug treatment, the potential ability of quercetin to improve the generalized hyperalgesia in mice with induced adenomyosis was evaluated by determining the body weight, pain modulation, examining the myometrial infiltration by histology examination of the uterus and detecting the expression of transient receptor potential cation channel subfamily V member 1 (Trpv‑1), phospho (p)‑p38 mitogen activated protein kinase p‑extracellular signal‑regulated kinase (p‑ERK) in DRG neurons via immunohistochemistry. The results demonstrated that treatment with quercetin improved the generalized hyperalgesia by extending the hotplate response latency, reduced myometrial infiltration and decreased the expression levels Trpv‑1, p‑p38 and p‑ERK in dorsal root ganglion neurons. The results indicated that quercetin decreases the incidence of hyperalgesia in mice with tamoxifen‑induced adenomyosis, and the potential mechanism is through reduced central sensitization, which may be a promising treatment for adenomyosis.

  2. Protective mechanism of quercetin on acute myocardial infarction in rats.

    PubMed

    Li, B; Yang, M; Liu, J W; Yin, G T

    2016-03-11

    To investigate the protective mechanism of quercetin on acute myocardial infarction (AMI) rats, an AMI rat model was established by ligating the left coronary anterior descending branch. The rats were randomly divided into the model group and low- and high-dose quercetin groups. The control group comprised sham-operated rats. The rats in the low- and high-dose quercetin groups were administered 100 and 400 mg/kg quercetin, respectively, by gavage. The rats in the control and model groups were administered isometric normal saline once daily for one week. The mRNA and protein levels of TNF-α and IL-1β in the myocardial tissue of rats were detected in each group by real time polymerase chain reaction and enzyme-linked immunosorbent assay. Malondialdehyde (MDA) content in the myocardial tissue and superoxide dismutase (SOD) and catalase (CAT) activities were detected using a colorimetric method. The level of apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling. Compared with those in the control group, the mRNA and protein levels of TNF-α, IL-1β and MDA content in the model, low-, and high-dose groups significantly increased. SOD and CAT activities decreased significantly. The cell apoptosis index increased significantly  (P < 0.05). Compared with those in the model group, the mRNA and protein levels of TNF-α and IL-1β and MDA content in myocardial tissue of rats in the low-dose and high-dose groups decreased significantly. SOD and CAT activities increased significantly. The cell apoptosis index significantly reduced (P < 0.05). In conclusion, quercetin has significant anti-inflammatory, antioxidant, and anti-apoptotic effects on AMI rats and can effectively protect against myocardium damage.

  3. Anti-proliferative effects of quercetin and catechin metabolites.

    PubMed

    Delgado, Laura; Fernandes, Iva; González-Manzano, Susana; de Freitas, Victor; Mateus, Nuno; Santos-Buelga, Celestino

    2014-04-01

    Dietary flavonoids have been associated with a lower incidence of some chronic diseases. However, the mechanisms behind the in vivo biological activity of flavonoids are still mostly unknown. Flavonoids are metabolized in the human body to conjugated forms (methylated, sulphated and glucuronidated derivatives) that should play a role in flavonoid activity. In this study, the anti-proliferative effects of conjugated metabolites of quercetin and (epi)catechin, major flavonoids in the diet, have been evaluated against three different cancer cell lines from breast (MCF-7), colon (Caco-2) and pancreas (BxPC-3) and one normal cell line of human foreskin fibroblasts (HFF-1), and compared with the effect of their unconjugated forms. Quercetin showed anti-proliferative activity on the three assayed cell models, whereas catechin and epicatechin were not active. Methylation on ring-B of quercetin decreased the anti-proliferative effects, especially when the methylation occurred in position 3' (isorhamnetin), although methylated metabolites still showed significant anti-proliferative activity. As to catechins, 4'-O-methyl-epicatechin and 3'-O-methyl-epicatechin were the only ones to show some activity on MCF-7 and BxPC-3 cell lines, respectively. Conjugation of quercetin with glucose or glucuronic acid eliminated the anti-proliferative effects of aglycones. Sulphated metabolites were also tested and found to be inactive in most of the explored cell lines, although quercetin-4'-O-sulphate and epicatechin-3'-O-sulphate still showed some anti-proliferative activity on MCF-7 and Caco-2 cells, respectively.

  4. Potential anti-cancer activity of 7-O-pentyl quercetin: Efficient, membrane-targeted kinase inhibition and pro-oxidant effect.

    PubMed

    Sassi, Nicola; Mattarei, Andrea; Espina, Virginia; Liotta, Lance; Zoratti, Mario; Paradisi, Cristina; Biasutto, Lucia

    2017-10-01

    Quercetin is a redox-active plant-derived flavonoid with potential anticancer effects, stemming largely from its interaction with a number of proteins, and in particular from inhibition of pro-life kinases. To improve efficacy, we reasoned that a local increase in concentration of the compound at the level of cell membranes would result in a more efficient interaction with membrane-associated signaling kinases. We report here the synthesis of all five isomeric quercetin derivatives in which an n-pentyl group was linked via an ether bond to each hydroxyl of the flavonoid kernel. This strategy proved effective in directing quercetin to cellular membranes, and revealed a remarkable dependence of the derivatives' bioactivity on the specific site of functionalization. The isomer bearing the pentyl group in position 7, Q-7P, turned out to be the most effective and promising derivative, selectively inducing apoptosis in tumoral and fast-growing cells, while sparing slow-growing, non-tumoral ones. Cytotoxicity for tumoral cells was strongly enhanced compared to quercetin itself. Q-7P induced massive ROS production, which however accounted only partially for cell death. Alterations in the levels of various signaling phospho-proteins were observed in a proteomics screen. An important contribution seems to come from inhibition of the PI3K/Akt pathway. This work opens new perspectives in developing membrane-associating, polyphenol-based anticancer agents. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Electrical characterization of Au/quercetin/n-Si heterojunction diode and optical analysis of quercetin thin film

    SciTech Connect

    Tombak, Ahmet; Özaydin, C.; Boğa, M.; Kiliçoğlu, T.

    2016-03-25

    Quercetin (3,5,7,3’,4’-pentahydroxyflavone, QE), one of the most widely distributed flavonoids in fruits and vegetables, has been reported to possess a wide variety of biological effects, including anti-oxidative, anti-inflammatory, anti-apoptosis, hepatoprotective, renoprotective and neuroprotective effects. In this study organic-inorganic junctions were fabricated by forming quercetin complex thin film using spin coating technique on n-Si and evaporating Au metal on the film. Optical properties of quercetin thin film were studied with the help of spectrophotometer. The current-voltage (I-V) characteristic of Au/quercetin/n-Si heterojunction diode was investigated at room temperature in dark. Some basic parameters of the diode such as ideality factor, rectification ratio, barrier height, series resistance and shunt resistance were calculated using dark current-voltage measurement. It was also seen that the device had good sensitivity to the light under 40-100 mW/cm{sup 2} illumination conditions.

  6. Oral and Intraperitoneal Administration of Quercetin Decreased Lymphocyte DNA Damage and Plasma Lipid Peroxidation Induced by TSA In Vivo

    PubMed Central

    Chan, Shu-Ting; Shiau, Rong-Jen; Liao, Jiunn-Wang; Yeh, Shu-Lan

    2014-01-01

    Our previous study showed that quercetin enhances the anticancer effect of trichostatin A (TSA) in xenograft mice given quercetin intraperitoneally (10 mg/kg, 3 times/week). Herein, we investigate whether quercetin administered orally exerts such an effect and prevents the cytotoxic side effects of TSA. We found that quercetin given orally (20 and 100 mg/kg, 3 times/week) failed to enhance the antitumor effect of TSA although it increased the total quercetin concentration more than quercetin administered intraperitoneally in the plasma. The compound quercetin-3-glucuronide (Q3G) increased the most. However, quercetin administered intraperitoneally increased the total quercetin level in tumor tissues more than oral quercetin. Oral and intraperitoneal administration of quercetin similarly decreased lymphocyte DNA damage and plasma lipid peroxidation level induced by TSA. Furthermore, we found that the enhancing effect of Q3G on the antitumor effect of TSA and the incorporation of Q3G was less than that of quercetin in A549 cells. However, we found that A549 cells possessed the ability to convert Q3G to quercetin. In conclusion, different from quercetin administered intraperitoneally, quercetin administered orally failed to enhance the antitumor effect of TSA because of its metabolic conversion. However, it prevented TSA-induced DNA damage and lipid peroxidation. PMID:24868531

  7. Quercetin impregnated chitosan-fibrin composite scaffolds as potential wound dressing materials - Fabrication, characterization and in vivo analysis.

    PubMed

    Vedakumari, Weslen S; Ayaz, Nazeeha; Karthick, Arun S; Senthil, Rethinam; Sastry, Thotapalli P

    2017-01-15

    The present study efforts at fabricating chitosan-fibrin composite (CF) scaffolds impregnated with quercetin for wound dressing application and aims at investigating their physicochemical properties. CF scaffolds were prepared by mixing acidic solution of chitosan with an alkaline solution of fibrin, to which quercetin (Q) was added, homogenized and lyophilized obtain Q-CF scaffold. FTIR spectra were used to determine the interactions between the functional groups of quercetin and CF scaffolds. TGA analysis revealed the decomposition of saccharide rings and amino acids of chitosan and fibrin at the temperature range of 255-400°C. Q-CF scaffold exhibited maximum tensile strength of 1.45MPa, an ideal mechanical strength for a wound dressing material. Q-CF scaffolds exhibited good bactericidal activity against Escherichia coli and Staphylococcus aureus. Biocompatibility of Q-CF scaffold was assessed using MTT assay, which elucidated its non-toxic property and excellent suitability for tissue engineering applications. In vivo wound healing experiments performed using albino rats revealed that topical application of Q-CF scaffold on open excision type of wounds can significantly accelerate the process of wound healing. These results suggest that Q-CF scaffold could serve as a promising wound dressing material.

  8. Study of fluorescence quenching mechanism between quercetin and tyrosine-H 2O 2-enzyme catalyzed product

    NASA Astrophysics Data System (ADS)

    Zhang, Miao; Lv, Qingluan; Yue, Ningning; Wang, Huaiyou

    2009-04-01

    Because of catalysis of horseradish peroxidase, the tyrosine reacted with H 2O 2 to form the product S which was a strong fluorescence substance. To the product S, the quercetin was acted as a quencher. The fluorescence quenching mechanism was studied by the measurement of fluorescence lifetime and based on the Stern-Volmer plot. The reaction mechanism, which was the static quenching process between quercetin and product S, was studied. The binding constant, K = 4.03 × 10 5 L mol -1 and the number of binding sites n = 1.09, were obtained against this reaction. The thermodynamic parameters were estimated. The data, Δ H = -75.68 kJ mol -1, Δ S = -147.9 J K -1 mol -1 and Δ G = -29.17 kJ mol -1 showed that the reaction was spontaneous and exothermic. What is more, both Δ H and Δ S were negative values indicated that van der Waals interaction and hydrogen bonding were the predominant intermolecular forces between quercetin and product S.

  9. Pharmacokinetics and bioavailability of the bioflavonoid biochanin A: effects of quercetin and EGCG on biochanin A disposition in rats.

    PubMed

    Moon, Young Jin; Morris, Marilyn E

    2007-01-01

    Little is known regarding pharmacokinetic (PK) or pharmacodynamic interactions of flavonoids with each other: this is of significance since multiple flavonoids are present in the diet and in dietary supplements. Our objective was to determine the effect of quercetin and (-)-epigallocatechin-3-gallate (EGCG), major flavonoids present in the diet, on the PK and bioavailability of biochanin A, a flavonoid with chemopreventive properties. BCA was administered to rats intravenously (5 mg/kg) or orally (16.67 or 50 mg/kg) with or without concomitant EGCG and quercetin. In vitro studies with the human intestinal Caco-2 and human hepatic HepG2 cell lines were performed to evaluate the effects of quercetin and EGCG on the cellular metabolism of BCA, and studies with human breast cancer MCF-7 cells that overexpress P-glycoprotein or BCRP (MCF-7/ADR and MCF-7/MX100 cells, respectively) or MDCK cells that express MRP2 (MDCK-MRP2) were performed to evaluate the effects of cellular efflux. An HPLC assay was used to determine plasma, urine, and cellular concentrations of BCA and the conjugated metabolites of BCA (following enzymatic hydrolysis). The coadministration of quercetin and EGCG significantly increased the BCA area under the plasma concentration vs time curve (AUC) in rats, after both iv and oral administration of BCA. The AUC of total BCA (unchanged + conjugated) was also increased. The increases in BCA AUC reflected predominantly increased bioavailability; this was true even after iv administration due to an apparent increase in the enterohepatic cycling of BCA. Our findings demonstrate for the first time that the administration of multiple flavonoids results in increased flavonoid bioavailability, as well as a decrease in clearance, potentially due to increased enterohepatic cycling.

  10. Identification of brain-targeted bioactive dietary quercetin-3-O-glucuronide as a novel intervention for Alzheimer's disease.

    PubMed

    Ho, Lap; Ferruzzi, Mario G; Janle, Elsa M; Wang, Jun; Gong, Bing; Chen, Tzu-Ying; Lobo, Jessica; Cooper, Bruce; Wu, Qing Li; Talcott, Stephen T; Percival, Susan S; Simon, James E; Pasinetti, Giulio Maria

    2013-02-01

    Epidemiological and preclinical studies indicate that polyphenol intake from moderate consumption of red wines may lower the relative risk for developing Alzheimer's disease (AD) dementia. There is limited information regarding the specific biological activities and cellular and molecular mechanisms by which wine polyphenolic components might modulate AD. We assessed accumulations of polyphenols in the rat brain following oral dosage with a Cabernet Sauvignon red wine and tested brain-targeted polyphenols for potential beneficial AD disease-modifying activities. We identified accumulations of select polyphenolic metabolites in the brain. We demonstrated that, in comparison to vehicle-control treatment, one of the brain-targeted polyphenol metabolites, quercetin-3-O-glucuronide, significantly reduced the generation of β-amyloid (Aβ) peptides by primary neuron cultures generated from the Tg2576 AD mouse model. Another brain-targeted metabolite, malvidin-3-O-glucoside, had no detectable effect on Aβ generation. Moreover, in an in vitro analysis using the photo-induced cross-linking of unmodified proteins (PICUP) technique, we found that quercetin-3-O-glucuronide is also capable of interfering with the initial protein-protein interaction of Aβ(1-40) and Aβ(1-42) that is necessary for the formation of neurotoxic oligomeric Aβ species. Lastly, we found that quercetin-3-O-glucuronide treatment, compared to vehicle-control treatment, significantly improved AD-type deficits in hippocampal formation basal synaptic transmission and long-term potentiation, possibly through mechanisms involving the activation of the c-Jun N-terminal kinases and the mitogen-activated protein kinase signaling pathways. Brain-targeted quercetin-3-O-glucuronide may simultaneously modulate multiple independent AD disease-modifying mechanisms and, as such, may contribute to the benefits of dietary supplementation with red wines as an effective intervention for AD.

  11. Absorption and tissue distribution of dietary quercetin and quercetin glycosides of apple skin in broiler chickens.

    PubMed

    Rupasinghe, H P Vasantha; Ronalds, Clinton M; Rathgeber, Bruce; Robinson, Robin A

    2010-05-01

    Apple skins are a rich source of flavonols, in particular quercetin (Q) glycosides. The objective of the present study was to investigate the presence of Q metabolites in plasma, various tissues, and excreta when the commercial broiler chicken's diet was supplemented with Q (0, 50, 150, 300, or 600 mg kg(-1) body weight per day), an apple skin extract (ASE; 50, 150 mg total phenolics kg(-1) body weight per day), or a dried apple skin powder (ASP; 50 mg total phenolics kg(-1) body weight per day). When Q was supplemented for 3 days, Q sulfate, Q glucuronide, Q glucoside glucuronide, Q glucoside sulfate, and isorhamnetin glucoside were detected by liquid chromatography-tandem mass spectrometry in the liver and duodenum. Deconjugated Q was also detected in the breast and thigh tissues of ASE- and ASP-supplemented broilers. Regardless of the source or concentration of Q, the antioxidant capacity measured by ferric reducing ability of plasma (FRAP) assay in the plasma and tissues of the broilers did not change significantly. As far as is known, this is the first report to demonstrate that Q and its glycosides can be absorbed and metabolized by broiler chickens.

  12. Enzymatic synthesis of quercetin oleate esters using Candida antarctica lipase B.

    PubMed

    Saik, Amy Yi Hsan; Lim, Yau Yan; Stanslas, Johnson; Choo, Wee Sim

    2017-02-01

    To investigate the lipase-catalyzed acylation of quercetin with oleic acid using Candida antarctica lipase B. Three acylated analogues were produced: quercetin 4'-oleate (C33H42O8), quercetin 3',4'-dioleate (C51H74O9) and quercetin 7,3',4'-trioleate (C69H106O10). Their identities were confirmed with UPLC-ESI-MS and (1)H NMR analyses. The effects of temperature, duration and molar ratio of substrates on the bioconversion yields varied across conditions. The regioselectivity of the acylated quercetin analogues was affected by the molar ratio of substrates. TLC showed the acylated analogues had higher lipophilicity (152% increase) compared to quercetin. Partition coefficient (log P) of quercetin 4'-oleate was higher than those of quercetin and oleic acid. Quercetin 4'-oleate was also stable over 28 days of storage. Quercetin oleate esters with enhanced lipophilicity can be produced via lipase-catalyzed reaction using C. antarctica lipase B to be used in topical applications.

  13. Quercetin Prevents Pyrrolizidine Alkaloid Clivorine-Induced Liver Injury in Mice by Elevating Body Defense Capacity

    PubMed Central

    Ji, Lili; Ma, Yibo; Wang, Zaiyong; Cai, Zhunxiu; Pang, Chun; Wang, Zhengtao

    2014-01-01

    Quercetin is a plant-derived flavonoid that is widely distributed in nature. The present study is designed to analyze the underlying mechanism in the protection of quercetin against pyrrolizidine alkaloid clivorine-induced acute liver injury in vivo. Serum transaminases, total bilirubin analysis, and liver histological evaluation demonstrated the protection of quercetin against clivorine-induced liver injury. Terminal dUTP nick end-labeling assay demonstrated that quercetin reduced the increased amount of liver apoptotic cells induced by clivorine. Western-blot analysis of caspase-3 showed that quercetin inhibited the cleaved activation of caspase-3 induced by clivorine. Results also showed that quercetin reduced the increase in liver glutathione and lipid peroxidative product malondialdehyde induced by clivorine. Quercetin reduced the enhanced liver immunohistochemical staining for 4-hydroxynonenal induced by clivorine. Results of the Mouse Stress and Toxicity PathwayFinder RT2 Profiler PCR Array demonstrated that the expression of genes related with oxidative or metabolic stress and heat shock was obviously altered after quercetin treatment. Some of the alterations were confirmed by real-time PCR. Our results demonstrated that quercetin prevents clivorine-induced acute liver injury in vivo by inhibiting apoptotic cell death and ameliorating oxidative stress injury. This protection may be caused by the elevation of the body defense capacity induced by quercetin. PMID:24905073

  14. Quercetin-containing self-nanoemulsifying drug delivery system for improving oral bioavailability.

    PubMed

    Tran, Thanh Huyen; Guo, Yi; Song, Donghui; Bruno, Richard S; Lu, Xiuling

    2014-03-01

    Quercetin is a dietary flavonoid with potential chemoprotective effects, but has low bioavailability because of poor aqueous solubility and low intestinal absorption. A quercetin-containing self-nanoemulsifying drug delivery system (Q-SNEDDS) was developed to form oil-in-water nanoemulsions in situ for improving quercetin oral bioavailability. On the basis of the quercetin solubility, emulsifying ability, and stability after dispersion in an aqueous phase, an optimal SNEDDS consisting of castor oil, Tween® 80, Cremophor® RH 40, and PEG 400 (20:16:34:30, w/w) was identified. Upon mixing with water, Q-SNEDDS formed a nanoemulsion having a droplet size of 208.8 ± 4.5 nm and zeta potential of -26.3 ± 1.2 mV. The presence of Tween® 80 and PEG 400 increased quercetin solubility and maintained supersaturated quercetin concentrations (5 mg/mL) for >1 month. The optimized Q-SNEDDS significantly improved quercetin transport across a human colon carcinoma (Caco-2) cell monolayer. Fluorescence imaging demonstrated rapid absorption of the Q-SNEDDS within 40 min of oral ingestion. Following oral administration of Q-SNEDDS in rats (15 mg/kg), the area under the concentration curve and maximum concentration of plasma quercetin after 24 h increased by approximately twofold and threefold compared with the quercetin control suspension. These data suggest that this Q-SNEDDS formulation can enhance the solubility and oral bioavailability of quercetin for appropriate clinical application.

  15. Effect of quercetin on paraoxonase 1 activity--studies in cultured cells, mice and humans.

    PubMed

    Boesch-Saadatmandi, C; Egert, S; Schrader, C; Coumoul, X; Coumol, X; Barouki, R; Muller, M J; Wolffram, S; Rimbach, G

    2010-02-01

    There is increasing evidence that the HDL-associated enzyme paraoxonase 1 (PON1) may have a protective function in the atherosclerotic process. An enhancement of PON1 activity by dietary factors including flavonoids is therefore of interest. Quercetin, a flavonol frequently present in fruits and vegetables has been shown to induce PON1 in cultured liver cells, but the in vivo efficacy of a dietary quercetin supplementation has yet not been evaluated. To this end, we fed laboratory mice quercetin-enriched diets with quercetin concentrations ranging from 0.05 to 2 mg/g diet for 6 weeks and determined the expression of the hepatic PON1 gene and its protein levels. Since we could establish a moderate but significant induction of PON1 mRNA levels by dietary quercetin in mice, we aimed to proof whether healthy human volunteers, given graded supplementary quercetin (50, 100 or 150 mg/day) for two weeks, would respond with likewise enhanced plasma paraoxonase activities. However, PON1 activity towards phenylacetate and paraoxon was not changed following quercetin supplementation in humans. Differences between mice and humans regarding the PON1 inducing activity of quercetin may be related to differences in quercetin metabolism. In mice, unlike in humans, a large proportion of quercetin is methylated to isorhamnetin which exhibits, according to our reporter gene data in cultured liver cells, a potent PON1 inducing activity.

  16. Quercetin Enhances Cisplatin Sensitivity of Human Osteosarcoma Cells by Modulating microRNA-217-KRAS Axis

    PubMed Central

    Zhang, Xian; Guo, Qinggong; Chen, Jingtao; Chen, Zhaohui

    2015-01-01

    Quercetin can suppress osteosarcoma cell growth and metastasis. However, other effects of quercetin on osteosarcoma remain largely unknown. This research aims to evaluate the effects of quercetin in combination with cisplatin as treatment for osteosarcoma and investigate its regulatory mechanism. Cell viability and apoptosis in 143B cell line were determined after treatment with quercetin and/or cisplatin. RT-PCR and Western blot analysis were performed to determine the RNA or protein expression levels. Moreover, transwell assay was used to evaluate metastasis. Furthermore, rescue experiments were performed to investigate the potential regulatory mechanism of the treatment. Results showed that quercetin with concentration that was equal to or greater than 10 μM inhibited 143B proliferation, while 5 μM quercetin enhanced the cisplatin sensitivity of 143B cells. Expression of miR-217 was upregulated after quercetin and/or cisplatin treatment, while its target KRAS was downregulated both at mRNA and protein levels. MiR-217 knockdown led to the loss of enhanced cisplatin sensitivity while miR-217 overexpression showed the opposite effects, indicating that quercetin regulated cisplatin sensitivity by modulating the miR-217-KRAS axis. In conclusion, 5 μM quercetin enhanced the cisplatin sensitivity by modulating the miR-217-KRAS axis. This finding suggests that quercetin may be administered with cisplatin to improve the treatment for osteosarcoma. PMID:26062553

  17. Inhibitory effect of quercetin on colorectal lung metastasis through inducing apoptosis, and suppression of metastatic ability.

    PubMed

    Kee, Ji-Ye; Han, Yo-Han; Kim, Dae-Seung; Mun, Jeong-Geon; Park, Jinbong; Jeong, Mi-Young; Um, Jae-Young; Hong, Seung-Heon

    2016-12-01

    Quercetin is a major dietary flavonoid found in a various fruits, vegetables, and grains. Although the inhibitory effects of quercetin have previously been observed in several types of cancer cells, the anti-metastatic effect of quercetin on colorectal metastasis has not been determined. This study investigated whether quercetin exhibits inhibitory effect on colorectal lung metastasis. The effects of quercetin on cell viability, mitogen-activated protein kinases (MAPKs) activation, migration, invasion, epithelial-mesenchymal transition (EMT) and lung metastasis were investigated. We investigated the effect of quercetin on metastatic colon cancer cells using WST assay, Annexin V assay, real-time RT-PCR, western blot analysis and gelatin zymography. The anti-metastatic effect of quercetin in vivo was confirmed in a colorectal lung metastasis model. Quercetin inhibited the cell viability of colon 26 (CT26) and colon 38 (MC38) cells and induced apoptosis through the MAPKs pathway in CT26 cells. Expression of EMT markers, such as E-, N-cadherin, β-catenin, and snail, were regulated by non-toxic concentrations of quercetin. Moreover, the migration and invasion abilities of CT26 cells were inhibited by quercetin through expression of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) regulation. Quercetin markedly decreased lung metastasis of CT26 cells in an experimental in vivo metastasis model. In conclusion, this study demonstrates for the first time that quercetin can inhibit the survival and metastatic ability of CT26 cells, and it can subsequently suppress colorectal lung metastasis in the mouse model. These results indicate that quercetin may be a potent therapeutic agent for the treatment of metastatic colorectal cancer. Copyright © 2016 Elsevier GmbH. All rights reserved.

  18. Quercetin induces tumor-selective apoptosis through downregulation of Mcl-1 and activation of Bax.

    PubMed

    Cheng, Senping; Gao, Ning; Zhang, Zhuo; Chen, Gang; Budhraja, Amit; Ke, Zunji; Son, Young-ok; Wang, Xin; Luo, Jia; Shi, Xianglin

    2010-12-01

    To investigate the in vivo antitumor efficacy of quercetin in U937 xenografts and the functional roles of Mcl-1 and Bax in quercetin-induced apoptosis in human leukemia. Leukemia cells were treated with quercetin, after which apoptosis, Mcl-1 expression, and Bax activation and translocation were evaluated. The efficacy of quercetin as well as Mcl-1 expression and Bax activation were investigated in xenografts of U937 cells. Administration of quercetin caused pronounced apoptosis in both transformed and primary leukemia cells but not in normal blood peripheral mononuclear cells. Quercetin-induced apoptosis was accompanied by Mcl-1 downregulation and Bax conformational change and mitochondrial translocation that triggered cytochrome c release. Knockdown of Bax by siRNA reversed quercetin-induced apoptosis and abrogated the activation of caspase and apoptosis. Ectopic expression of Mcl-1 attenuated quercetin-mediated Bax activation, translocation, and cell death. Conversely, interruption of Mcl-1 by siRNA enhanced Bax activation and translocation, as well as lethality induced by quercetin. However, the absence of Bax had no effect on quercetin-mediated Mcl-1 downregulation. Furthermore, in vivo administration of quercetin attenuated tumor growth in U937 xenografts. The TUNEL-positive apoptotic cells in tumor sections increased in quercetin-treated mice as compared with controls. Mcl-1 downregulation and Bax activation were also observed in xenografts. These data suggest that quercetin may be useful for the treatment of leukemia by preferentially inducing apoptosis in leukemia versus normal hematopoietic cells through a process involving Mcl-1 downregulation, which, in turn, potentiates Bax activation and mitochondrial translocation, culminating in apoptosis. ©2010 AACR.

  19. Quercetin, luteolin and epigallocatechin gallate alleviate TXNIP and NLRP3-mediated inflammation and apoptosis with regulation of AMPK in endothelial cells.

    PubMed

    Wu, Jianjun; Xu, Xiaoshan; Li, Yi; Kou, Junping; Huang, Fang; Liu, Baolin; Liu, Kang

    2014-12-15

    Endoplasmic reticulum stress (ER stress)-associated thioredoxin-interacting protein (TXNIP) and NOD-like receptor pyrin domain containing-3 (NLRP3) signaling is a key event in the endothelial dysfunction. It induces the IL-1β production and thus accounts for inflammation and cell death. Quercetin, luteolin and epigallocatechin gallate (EGCG) are flavonoids with beneficial effects on cardiovascular functions, and we wondered whether these flavonoids protect endothelial functions against ER stress-associated impairments. Palmitate stimulation evoked oxidative stress and then induced TXNIP and NLRP3 inflammasome activation in the endothelial cells. Quercetin, luteolin and EGCG reduced reactive oxygen species production and inhibited TXNIP and NLRP3 inflammasome activation, lead to the downregulation of IL-1β expression. Meanwhile, these agents protected cells from apoptosis by restoration of mitochondrial membrane potential (Δψm) and inhibition of caspase-3 activity. PA stimulation induced inflammation accompanied by the loss of NO production in endothelial cells, but these alterations were reversed by treatment with quercetin, luteolin and EGCG. Co-treatment with AMPK inhibitor compound C diminished the beneficial effects of these flavonoids, suggesting the involvement of AMPK. In conclusion, quercetin, luteolin and EGCG inhibited ER stress-associated TXNIP and NLRP3 inflammasome activation, and thereby protected endothelial cells from inflammatory and apoptotic damage. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. New Treatment of Medullary and Papillary Human Thyroid Cancer: Biological Effects of Hyaluronic Acid Hydrogel Loaded With Quercetin Alone or in Combination to an Inhibitor of Aurora Kinase.

    PubMed

    Quagliariello, Vincenzo; Armenia, Emilia; Aurilio, Caterina; Rosso, Francesco; Clemente, Ottavia; de Sena, Gabriele; Barbarisi, Manlio; Barbarisi, Alfonso

    2016-08-01

    The aim of this paper is based on the use of a hyaluronic acid hydrogel of Quercetin tested alone and in combination to an inhibitor of Aurora Kinase type A and B (SNS-314) on human medullary and papillary thyroid cancer cells. Biological investigations were focused on the cellular uptake of the hydrogel, cell viability, antioxidant, and cytokines secretion studies. Quercetin delivered from hydrogel show a time and CD44 dependent interaction with both cell lines with significant anti-inflammatory effects. Combination of Quercetin and SNS-314 leads to a synergistic cytotoxic effect on medullary TT and papillary BCPAP cell lines with a significant reduction of the IC50 value. These results, highlights the importance of synergistic effect of the hyaluronic acid hydrogel of Quercetin with SNS-314 in the regulation of human thyroid cancer cell proliferation and emphasize the anti-tumor activity of these molecules. J. Cell. Physiol. 231: 1784-1795, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  1. New benzophenone and quercetin galloyl glycosides from Psidium guajava L.

    PubMed Central

    Matsuzaki, Keiichi; Ishii, Rie; Kobiyama, Kaori

    2010-01-01

    New benzophenone and flavonol galloyl glycosides were isolated from an 80% MeOH extract of Psidium guajava L. (Myrtaceae) together with five known quercetin glycosides. The structures of the novel glycosides were elucidated to be 2,4,6-trihydroxybenzophenone 4-O-(6″-O-galloyl)-β-d-glucopyranoside (1, guavinoside A), 2,4,6-trihydroxy-3,5-dimethylbenzophenone 4-O-(6″-O-galloyl)-β-d-glucopyranoside (2, guavinoside B), and quercetin 3-O-(5″-O-galloyl)-α-l-arabinofuranoside (3, guavinoside C) by NMR, MS, UV, and IR spectroscopies. Isolated phenolic glycosides showed significant inhibitory activities against histamine release from rat peritoneal mast cells, and nitric oxide production from a murine macrophage-like cell line, RAW 264.7. PMID:20354804

  2. Preparation and characterization of quercetin and rutin cyclodextrin inclusion complexes.

    PubMed

    Sri, K Vijaya; Kondaiah, A; Ratna, J Vijaya; Annapurna, A

    2007-03-01

    The objective of the present study is to prepare and characterize cyclodextrin inclusion complexes of quercetin and rutin to improve their aqueous solubility and dissolution properties. Inclusion complexes of quercetin and rutin with beta-cyclodextrin (beta-CD) and hydroxyl propyl-beta-cyclodextrin (HP-beta-CD) were prepared by kneading and coevaporation methods. Characterization of inclusion complexes was done by phase solubility analysis and was supported by X-ray powder diffractometry (XRD), differential scanning calorimetry (DSC), and Fourier-transform infra red spectroscopy (FT-IR) analysis. Inclusion complexes exhibited higher rates of dissolution than the corresponding physical mixtures and pure drug. Higher dissolution rates were observed with HP-beta-CD kneaded complexes in comparison to the products with beta-CD.

  3. Isolation and Identification of Quercetin Degrading Bacteria from Human Fecal Microbes

    PubMed Central

    Zhang, Zhichao; Peng, Xichun; Li, Shaoting; Zhang, Ning; wang, Yong; Wei, Hua

    2014-01-01

    Quercetin has a wide range of biological properties. The gut microflora can often modulate its biological activity and their potential health effects. There still is a lack of information about gut bacteria involving in this process. The strains of gut microbes from human feces that can transform quercetin were isolated and identified by in vitro fermentation. The results showed that Escherichia coli, Stretococcus lutetiensis, Lactobacillus acidophilus, Weissella confusa, Enterococcus gilvus, Clostridium perfringens and Bacteroides fragilis have the various ability of degrading quercetin. Among them, C. perfringens and B. fragilis were discovered to have the strongest ability of degrading quercetin. Additionally, quercetin can't inhibit the growth of C. perfringens. In conclusion, many species of gut microbiota can degrade quercetin, but their ability are different. PMID:24594786

  4. Isolation and identification of quercetin degrading bacteria from human fecal microbes.

    PubMed

    Zhang, Zhichao; Peng, Xichun; Li, Shaoting; Zhang, Ning; Wang, Yong; Wei, Hua

    2014-01-01

    Quercetin has a wide range of biological properties. The gut microflora can often modulate its biological activity and their potential health effects. There still is a lack of information about gut bacteria involving in this process. The strains of gut microbes from human feces that can transform quercetin were isolated and identified by in vitro fermentation. The results showed that Escherichia coli, Stretococcus lutetiensis, Lactobacillus acidophilus, Weissella confusa, Enterococcus gilvus, Clostridium perfringens and Bacteroides fragilis have the various ability of degrading quercetin. Among them, C. perfringens and B. fragilis were discovered to have the strongest ability of degrading quercetin. Additionally, quercetin can't inhibit the growth of C. perfringens. In conclusion, many species of gut microbiota can degrade quercetin, but their ability are different.

  5. Research Progress in the Modification of Quercetin Leading to Anticancer Agents.

    PubMed

    Massi, Alessandro; Bortolini, Olga; Ragno, Daniele; Bernardi, Tatiana; Sacchetti, Gianni; Tacchini, Massimo; De Risi, Carmela

    2017-07-29

    The flavonoid quercetin (3,3',4',5,7-pentahydroxyflavone) is widely distributed in plants, foods, and beverages. This polyphenol compound exhibits varied biological actions such as antioxidant, radical-scavenging, anti-inflammatory, antibacterial, antiviral, gastroprotective, immune-modulator, and finds also application in the treatment of obesity, cardiovascular diseases and diabetes. Besides, quercetin can prevent neurological disorders and exerts protection against mitochondrial damages. Various in vitro studies have assessed the anticancer effects of quercetin, although there are no conclusive data regarding its mode of action. However, low bioavailability, poor aqueous solubility as well as rapid body clearance, fast metabolism and enzymatic degradation hamper the use of quercetin as therapeutic agent, so intense research efforts have been focused on the modification of the quercetin scaffold to obtain analogs with potentially improved properties for clinical applications. This review gives an overview of the developments in the synthesis and anticancer-related activities of quercetin derivatives reported from 2012 to 2016.

  6. Different profiles of quercetin metabolites in rat plasma: comparison of two administration methods.

    PubMed

    Kawai, Yoshichika; Saito, Satomi; Nishikawa, Tomomi; Ishisaka, Akari; Murota, Kaeko; Terao, Junji

    2009-03-23

    The bioavailability of polyphenols in human and rodents has been discussed regarding their biological activity. We found different metabolite profiles of quercetin in rat plasma between two administration procedures. A single intragastric administration (50 mg/kg) resulted in the appearance of a variety of metabolites in the plasma, whereas only a major fraction was detected by free access (1% quercetin). The methylated/non-methylated metabolites ratio was much higher in the free access group. Mass spectrometric analyses showed that the fraction from free access contained highly conjugated quercetin metabolites such as sulfo-glucuronides of quercetin and methylquercetin. The metabolite profile of human plasma after an intake of onion was similar to that with intragastric administration in rats. In vitro oxidation of human low-density lipoprotein showed that methylation of the catechol moiety of quercetin significantly attenuated the antioxidative activity. These results might provide information about the bioavailability of quercetin when conducting animal experiments.

  7. Antagonism of quercetin against tremor induced by unilateral striatal lesion of 6-OHDA in rats.

    PubMed

    Mu, Xin; Yuan, Xia; Du, Li-Da; He, Guo-Rong; Du, Guan-Hua

    2016-01-01

    Quercetin, a flavonoid present in many plants, is reported to be effective in models of neurodegenerative diseases. The aim of the present study was to evaluate the anti-tremor effects of quercetin in 6-hydroxydopamine (6-OHDA)-induced rat model of Parkinson's disease. In rats, quercetin had no effect on apomorphine-induced rotations, but it could significantly attenuate muscle tremor of 6-OHDA lesioned rats. Interestingly, quercetin could decrease the burst frequency in a dose- and time-dependent manner. These results suggest that quercetin may have a protective effect on models to mimic muscle tremors of Parkinson's disease. This effect of quercetin may be associated with serotonergic system, but further study is needed.

  8. Quercetin, not caffeine, is a major neuroprotective component in coffee.

    PubMed

    Lee, Moonhee; McGeer, Edith G; McGeer, Patrick L

    2016-10-01

    Epidemiologic studies indicate that coffee consumption reduces the risk of Parkinson's disease and Alzheimer's disease. To determine the factors involved, we examined the protective effects of coffee components. The test involved prevention of neurotoxicity to SH-SY5Y cells that was induced by lipopolysaccharide plus interferon-γ or interferon-γ released from activated microglia and astrocytes. We found that quercetin, flavones, chlorogenic acid, and caffeine protected SH-SY5Y cells from these toxins. They also reduced the release of tumor necrosis factor-α and interleukin-6 from the activated microglia and astrocytes and attenuated the activation of proteins from P38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa light chain enhancer of activated B cells (NFκB). After exposure to toxin containing glial-stimulated conditioned medium, we also found that quercetin reduced oxidative/nitrative damage to DNA, as well as to the lipids and proteins of SH-SY5Y cells. There was a resultant increase in [GSH]i in SH-SY5Y cells. The data indicate that quercetin is the major neuroprotective component in coffee against Parkinson's disease and Alzheimer's disease.

  9. Biocompatible nanoparticles for sustained topical delivery of anticancer phytoconstituent quercetin.

    PubMed

    Sahu, Sneha; Saraf, Swarnlata; Kaur, Chanchal Deep; Saraf, Shailendra

    2013-07-01

    This study describes the release and retention of a herbal lipophilic drug in sustained and controlled manner in skin layers, given topically, intended for skin cancer. Quercetin -loaded nanoparticles were prepared by nanoprecipitation technique using ethylcellulose as polymer. Ethylcellulose was selected as it is biocompatible, but non-biodegradable and hence can act as a reservoir in skin furrows and ducts. It was observed that the Quercetin: Ethylcellulose: Tween 80 at different ratios affects particle sizes along with yield and entrapment efficiency. It was found that the size of nanoparticles could be varied by changing the speed of agitation and sonication. The nanoparticles were prepared in particle size range 228.77 +/- 2.0 nm and the zeta potential of the selected formulation were found to be -16.7 mV, which shows the stability of the preparation. The percent entrapment efficiency was found to be in the range from 51.96 to 53.93% and percent loading capacity in the range 34.19 to 5.12%. The amount of drug release from nanoparticles and of drug retained in skin was compared using ex vivo study which shows that the drug being lipophilic could be retained in the skin for longer duration thus reducing the dose and frequency of drug administration. Further the amount of drug reaching to other organs is also reduced since the systemic absorption of drug was low. Thus, Quercetin loaded nanoparticles were prepared for topical use.

  10. Quercetin nanoparticles display antitumor activity via proliferation inhibition and apoptosis induction in liver cancer cells.

    PubMed

    Ren, Ke-Wei; Li, Ya-Hua; Wu, Gang; Ren, Jian-Zhuang; Lu, Hui-Bin; Li, Zong-Ming; Han, Xin-Wei

    2017-04-01

    Quercetin is a potent cancer therapeutic agent and dietary antioxidant present in fruit and vegetables. Quercetin prevents tumor proliferation by inducing cell cycle arrest and is a well known cancer therapeutic agent and autophagy mediator. Recent studies showed that drug delivery by nanoparticles have enhanced efficacy with reduced side effects. In this regard, gold-quercetin into poly(DL-lactide-co-glycolide) nanoparticles was examined. In this study, we explored the role and possible underlying mechanisms of quercetin nanoparticle in regulation of antitumor activity in liver cancer cells. Treatment with quercetin nanoparticle effectively inhibited the liver cancer cell proliferation, cell migration and colony formation, thus suppressing liver cancer progression. Quercetin nanoparticle also upregulated apoptosis markedly. Further study suggested that quercetin nanoparticle accelerated the cleavage of caspase-9, caspase-3, and induced the up-releasing of cytochrome c (Cyto-c), contributing to apoptosis in liver cancer cells. Quercetin nanoparticles also promoted telomerase reverse transcriptase (hTERT) inhibition through reducing AP-2β expression and decreasing its binding to hTERT promoter. In addition, quercetin nanoparticle had an inhibitory role in cyclooxygenase 2 (COX-2) via suppressing the NF-κB nuclear translocation and its binding to COX-2 promoter. Quercetin nanoparticle also inactivated Akt and ERK1/2 signaling pathway. Taken together, our results suggested that quercetin nanoparticle had an antitumor effect by inactivating caspase/Cyto-c pathway, suppressing AP-2β/hTERT, inhibiting NF-κB/COX-2 and impeding Akt/ERK1/2 signaling pathways. Our results provided new mechanistic basis for further investigation of quercetin nanoparticles to find potential therapeutic strategies and possible targets for liver cancer inhibition.

  11. Quercetin from shallots (Allium cepa L. var. aggregatum) is more bioavailable than its glucosides.

    PubMed

    Wiczkowski, Wieslaw; Romaszko, Jerzy; Bucinski, Adam; Szawara-Nowak, Dorota; Honke, Joanna; Zielinski, Henryk; Piskula, Mariusz K

    2008-05-01

    The lipophilic character of quercetin suggests that it can cross enterocyte membranes via simple diffusion. Therefore, it should be more bioavailable than its glucosides, which require preliminary hydrolysis or active transport for absorption. However, the published human studies show that quercetin is less bioavailable than its glucosides. Assuming that low bioavailability of quercetin aglycone provided to humans as a pure substance is the result of its low solubility in the digestive tract, we studied its bioavailability from dietary sources in which quercetin was dispersed in the food matrix. In a randomized crossover study, 9 volunteers took a single dose of either shallot flesh (99.2% quercetin glucosides and 0.8% quercetin aglycone) or dry shallot skin (83.3% quercetin aglycone and 16.7% quercetin glucosides), providing 1.4 mg quercetin per kg of body weight. Blood samples were collected before and after consumption of shallot preparations. Plasma quercetin was measured on HPLC with electrochemical detection after plasma enzymatic treatment. The maximum plasma quercetin concentration of 1.02 +/- 0.13 micromol/L was reached at 2.33 +/- 0.50 h after shallot flesh consumption compared with 3.95 +/- 0.62 micromol/L at 2.78 +/- 0.15 h after dry skin consumption. The area under the concentration-time curve after dry skin consumption was 47.23 +/- 7.53 micromol x h(-1) x L(-1) and was significantly higher than that after shallot flesh intake (22.23 +/- 2.32 micromol x h(-1) x L(-1)). When provided along with dietary sources, quercetin aglycone is more bioavailable than its glucosides in humans. Results point to the food matrix as a key factor.

  12. Structural basis of the anti-inflammatory activity of quercetin: inhibition of the 5-hydroxytryptamine type 2 receptor.

    PubMed

    Rotelli, Alejandra Ester; Aguilar, Carlos Fernando; Pelzer, Lilian Eugenia

    2009-09-01

    The anti-inflammatory activity of quercetin was evaluated through serotonin-induced rat-paw edema. The experiments showed that quercetin had an important effect on acute inflammatory processes. Docking of serotonin and quercetin into the homology model of the 5-Hydroxytryptamine Type 2 Receptor allowed to analyze the structural basis of the anti-inflammatory activity. Results showed that serotonin and quercetin bind in the same region of the active site with a similar binding energy but quercetin has a much bigger inhibition constant. Therefore, it seems possible that quercetin may act as a natural inhibitor of the receptor blocking the acute inflammation generated by serotonin.

  13. Inhibition of constitutive endothelial NO-synthase activity by tannin and quercetin.

    PubMed

    Chiesi, M; Schwaller, R

    1995-02-14

    The effect of natural polyphenols on three isoforms of NO-synthase was investigated. Among the compounds tested, tannin was the most potent, inhibiting endothelial constitutive NO synthase (eNOS) with an IC50 of 2.2 microM. Other NOS isoforms (i.e. neuronal constitutive NOS and smooth muscle inducible NOS) were also inhibited but at much higher concentrations (selectivity ratio of approx. 20-30). Quercetin was also an effective but less potent inhibitor of eNOS (IC50 = 220 microM). The kinetics of tannin inhibition were investigated to gather information on the mechanism of action. Tannin did not interfere with the interaction of the enzyme with the co-substrates L-arginine and NADPH nor with the cofactor tetrahydrobiopterin. The inhibition level was also independent of free Ca2+ concentration as well as of the presence of high exogenous calmodulin concentrations.

  14. Fluorescence enhancement of quercetin complexes by silver nanoparticles and its analytical application

    NASA Astrophysics Data System (ADS)

    Liu, Ping; Zhao, Liangliang; Wu, Xia; Huang, Fei; Wang, Minqin; Liu, Xiaodan

    2014-03-01

    It is found that the plasmon effect of silver nanoparticles (AgNPs) helps to enhance the fluorescence intensity of the quercetin (Qu) and nucleic acids system. Qu exhibited strong fluorescence enhancement when it bound to nucleic acids in the presence of AgNPs. Based on this, a sensitive method for the determination of nucleic acids was developed. The detection limits for the nucleic acids (S/N = 3) were reduced to the ng mL-1 level. The interaction mechanism of the AgNPs-fish sperm DNA (fsDNA)-Qu system was also investigated in this paper. This complex system of Qu and AgNPs was also successfully used for the detection of nucleic acids in agarose gel electrophoresis analysis. Preliminary results indicated that AgNPs also helped to improve sensitivity in the fluorescence image analysis of Qu combined with cellular contents in Arabidopsis thaliana protoplasts.

  15. Identification of brain-targeted bioactive dietary quercetin-3-O-glucuronide as a novel intervention for Alzheimer's disease

    PubMed Central

    Ho, Lap; Ferruzzi, Mario G.; Janle, Elsa M.; Wang, Jun; Gong, Bing; Chen, Tzu-Ying; Lobo, Jessica; Cooper, Bruce; Wu, Qing Li; Talcott, Stephen T.; Percival, Susan S.; Simon, James E.; Pasinetti, Giulio Maria

    2013-01-01

    Epidemiological and preclinical studies indicate that polyphenol intake from moderate consumption of red wines may lower the relative risk for developing Alzheimer's disease (AD) dementia. There is limited information regarding the specific biological activities and cellular and molecular mechanisms by which wine polyphenolic components might modulate AD. We assessed accumulations of polyphenols in the rat brain following oral dosage with a Cabernet Sauvignon red wine and tested brain-targeted polyphenols for potential beneficial AD disease-modifying activities. We identified accumulations of select polyphenolic metabolites in the brain. We demonstrated that, in comparison to vehicle-control treatment, one of the brain-targeted polyphenol metabolites, quercetin-3-O-glucuronide, significantly reduced the generation of β-amyloid (Aβ) peptides by primary neuron cultures generated from the Tg2576 AD mouse model. Another brain-targeted metabolite, malvidin-3-O-glucoside, had no detectable effect on Aβ generation. Moreover, in an in vitro analysis using the photo-induced cross-linking of unmodified proteins (PICUP) technique, we found that quercetin-3-O-glucuronide is also capable of interfering with the initial protein-protein interaction of Aβ1–40 and Aβ1–42 that is necessary for the formation of neurotoxic oligomeric Aβ species. Lastly, we found that quercetin-3-O-glucuronide treatment, compared to vehicle-control treatment, significantly improved AD-type deficits in hippocampal formation basal synaptic transmission and long-term potentiation, possibly through mechanisms involving the activation of the c-Jun N-terminal kinases and the mitogen-activated protein kinase signaling pathways. Brain-targeted quercetin-3-O-glucuronide may simultaneously modulate multiple independent AD disease-modifying mechanisms and, as such, may contribute to the benefits of dietary supplementation with red wines as an effective intervention for AD.—Ho, L., Ferruzzi, M. G

  16. Quercetin Potentiates Doxorubicin Mediated Antitumor Effects against Liver Cancer through p53/Bcl-xl

    PubMed Central

    Wang, Guanyu; Sharma, Sherven; Dong, Qinghua

    2012-01-01

    Background The dose-dependent toxicities of doxorubicin (DOX) limit its clinical applications, particularly in drug-resistant cancers, such as liver cancer. In this study, we investigated the role of quercetin on the antitumor effects of DOX on liver cancer cells and its ability to provide protection against DOX-mediated liver damage in mice. Methodology and Results The MTT and Annexin V/PI staining assay demonstrated that quercetin selectively sensitized DOX-induced cytotoxicity against liver cancer cells while protecting normal liver cells. The increase in DOX-mediated apoptosis in hepatoma cells by quercetin was p53-dependent and occurred by downregulating Bcl-xl expression. Z-VAD-fmk (caspase inhibitor), pifithrin-α (p53 inhibitor), or overexpressed Bcl-xl decreased the effects of quercetin on DOX-mediated apoptosis. The combined treatment of quercetin and DOX significantly reduced the growth of liver cancer xenografts in mice. Moreover, quercetin decreased the serum levels of alanine aminotransferase and aspartate aminotransferase that were increased in DOX-treated mice. Quercetin also reversed the DOX-induced pathological changes in mice livers. Conclusion and Significance These results indicate that quercetin potentiated the antitumor effects of DOX on liver cancer cells while protecting normal liver cells. Therefore, the development of quercetin may be beneficial in a combined treatment with DOX for increased therapeutic efficacy against liver cancer. PMID:23240061

  17. A new acylated quercetin glycoside from the leaves of Stevia rebaudiana Bertoni.

    PubMed

    Li, Jun; Jiang, Hua; Shi, Renbing

    2009-01-01

    A new acylated quercetin glycoside quercetin-3-O-(4'''-O-trans-caffeoyl)-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-galacopyranoside (1), along with luteolin (2), quercetin (3), luteolin-7-O-beta-D-glucoside (4), apigenin-7-O-beta-D-glucoside (5), quercitrin (6), quercetin-3-O-beta-D-arabinoside (7) and 4,5-di-O-caffeoyl quinic acid (8) have been isolated from the leaves of Stevia rebaudiana Bertoni. The structures of these compounds were determined by spectroscopic methods (1H- and 13C-NMR, IR and MS) and by 2D-NMR experiments.

  18. The effects of quercetin supplementation on body composition, exercise performance and muscle damage indices in athletes.

    PubMed

    Askari, Gholamreza; Ghiasvand, Reza; Paknahad, Zamzam; Karimian, Jahangir; Rabiee, Katayoun; Sharifirad, Gholamreza; Feizi, Awat

    2013-01-01

    Flavonoids comprise a large group of plant metabolites, 6,000 of which have been identified to date. Some studies have shown the increased aerobic performance and maximal oxygen consumption (VO(2max)) and therefore fitness following quercetin intake as a result of elevated number of intracellular mitochondria caused by the flavonoid. This double-blind clinical trial comprised 60 male students having an athletic history of at least 3 years. Body composition, exercise performance, and some blood biomarkers were analyzed. The individuals were selected by convenient sampling, and then were assigned into four groups of equal number by using permuted block randomization. The first to fourth groups received a 500 mg supplemental quercetin capsule plus a 250 mg vitamin C pill, a 500 mg supplemental quercetin capsule plus a 250 mg placebo vitamin C pill, a 500 mg placebo quercetin capsule plus a 250 mg vitamin C pill, and a 500 mg placebo quercetin capsule plus a 250 mg placebo vitamin C pill, respectively, daily for 8 weeks. The participants were asked to continue their routine diet and physical activity during the study and they were monitored through phone calls or text messages. Lean body mass, total body water, basal metabolic rate, and total energy expenditure increased significantly in the quercetin group after intervention. On the other hand, VO(2max) increased in the "quercetin" and "quercetin + vitamin C" groups following the intervention, non-significantly. Our findings suggest that supplementation with quercetin in athletes may improve some indices of performance.

  19. Quercetin suppresses HeLa cells by blocking PI3K/Akt pathway.

    PubMed

    Xiang, Tao; Fang, Yong; Wang, Shi-Xuan

    2014-10-01

    To explore the effect of quercetin on the proliferation and apoptosis of HeLa cells, HeLa cells were incubated with quercetin at different concentrations. Cell viability was evaluated by MTT assay, cell apoptosis was detected by Annexin-V/PI double labeled cytometry and DNA ladder assay. Cell cycle was flow cytometrically determined and the morphological changes of the cells were observed under a fluorescence microscope after Hoechst 33258 staining and the apoptosis-related proteins in the HeLa cells were assessed by Western blotting. The results showed that quercetin significantly inhibited the growth of HeLa cells and induced obvious apoptosis in vitro in a time- and dose-dependent manner. Moreover, quercetin induced apoptosis of HeLa cells in cell cycle-dependent manner because quercetin could induce arrest of HeLa cells at G0/G1 phase. Quercetin treatment down-regulated the expression of the PI3K and p-Akt. In addition, quercetin could down-regulate expression of bcl-2, up-regulate Bax, but exerted no effect on the overall expression of Akt. We are led to conclude that quercetin induces apoptosis via PI3k/Akt pathways, and quercetin has potential to be used as an anti-tumor agent against human cervix cancer.

  20. [Mechanisms for quercetin in prevention of lung cancer cell growth and metastasis].

    PubMed

    Zhao, Xin; Zhang, Jian

    2015-06-01

    To study the effect of quercetin, an inhibitor of matrix metalloproteinases 9 (MMP-9), on the growth and metastasis of lung cancer cells and the underlying mechanisms.
 We evaluated the inhibitory effect and the inhibitory kinetics of quercetin on MMP-9 by ELISA and enzyme inhibition kinetics, and the inhibitory effect of quercetin on the growth of lung cancer cell (A549) by MTT. The effect of quercetin on levels of MMP-9 (mRNA and protein) and TGF-β1 (protein) in A549 were measured by RT-PCR and Western blot, respectively. The synergistic inhibition effect of quercetin plus TIMP-1 on the growth of lung cancer cell A549 was discussed.
 Quercetin induced the apoptosis of A549. It was a reversible competitive inhibitor of MMP-9 (half inhibition rate IC50 of 5.25 μmol/L, inhibition constant Ki was 2.18 μmol/L). With the increase in quercetin concentration, the levels of MMP-9 (mRNA and protein) and TGF-β1 (protein) were decreased, and the number of tumor cells on wear filter membrane was reduced. The combination of quercetin (at low concentrations) with TIMP-1 showed synergistic inhibitory effect on the growth of A549 cells. 
 Quercetin is a competitive inhibitor of MMP-9 and could downregulate the expression of MMP-9 and TGF-β1, which plays an important role in A549 apoptosis.

  1. Quercetin, Morin, Luteolin, and Phloretin Are Dietary Flavonoid Inhibitors of Monocarboxylate Transporter 6.

    PubMed

    Jones, Robert S; Parker, Mark D; Morris, Marilyn E

    2017-09-05

    Monocarboxylate transporter 6 (MCT6; SLC16A5) has been recognized for its role as a xenobiotic transporter, with characterized substrates probenecid, bumetanide, and nateglinide. To date, the impact of commonly ingested dietary compounds on MCT6 function has not been investigated, and therefore, the objective of this study was to evaluate a variety of flavonoids for their potential MCT6-specific interactions. Flavonoids are a large group of polyphenolic phytochemicals found in commonly consumed plant-based products that have been recognized for their dietary health benefits. The uptake of bumetanide in human MCT6 gene-transfected Xenopus laevis oocytes was significantly decreased in the presence of a variety of flavonoids (e.g., quercetin, luteolin, phloretin, and morin), but was not significantly affected by flavonoid glycosides (e.g., naringin, rutin, phlorizin). The IC50 values of quercetin, phloretin, and morin were determined to be 25.3 ± 3.36, 17.3 ± 2.37, and 33.1 ± 3.29 μM, respectively. The mechanism of inhibition of phloretin was reversible and competitive, with a Ki value of 22.8 μM. Furthermore, typical MCT substrates were also investigated for their potential interactions with MCT6. Substrates of MCTs 1, 2, 4, 8, and 10 did not cause any significant decrease in MCT6-mediated bumetanide uptake, suggesting that MCT6 has distinct compound selectivity. In summary, these results suggest that dietary aglycon flavonoids may significantly alter the pharmacokinetics and pharmacodynamics of bumetanide and other MCT6-specific substrates, and may represent potential substrates for MCT6.

  2. Dietary quercetin exacerbates the development of estrogen-induced breast tumors in female ACI rats.

    PubMed

    Singh, Bhupendra; Mense, Sarah M; Bhat, Nimee K; Putty, Sandeep; Guthiel, William A; Remotti, Fabrizio; Bhat, Hari K

    2010-09-01

    Phytoestrogens are plant compounds that structurally mimic the endogenous estrogen 17beta-estradiol (E(2)). Despite intense investigation, the net effect of phytoestrogen exposure on the breast remains unclear. The objective of the current study was to examine the effects of quercetin on E(2)-induced breast cancer in vivo. Female ACI rats were given quercetin (2.5 g/kg food) for 8 months. Animals were monitored weekly for palpable tumors, and at the end of the experiment, rats were euthanized, breast tumor and different tissues excised so that they could be examined for histopathologic changes, estrogen metabolic activity and oxidant stress. Quercetin alone did not induce mammary tumors in female ACI rats. However, in rats implanted with E(2) pellets, co-exposure to quercetin did not protect rats from E(2)-induced breast tumor development with 100% of the animals developing breast tumors within 8 months of treatment. No changes in serum quercetin levels were observed in quercetin and quercetin+E(2)-treated groups at the end of the experiment. Tumor latency was significantly decreased among rats from the quercetin+E(2) group relative to those in the E(2) group. Catechol-O-methyltransferase (COMT) activity was significantly downregulated in quercetin-exposed mammary tissue. Analysis of 8-isoprostane F(2alpha) (8-iso-PGF(2alpha)) levels as a marker of oxidant stress showed that quercetin did not decrease E(2)-induced oxidant stress. These results indicate that quercetin (2.5 g/kg food) does not confer protection against breast cancer, does not inhibit E(2)-induced oxidant stress and may exacerbate breast carcinogenesis in E(2)-treated ACI rats. Inhibition of COMT activity by quercetin may expose breast cells chronically to E(2) and catechol estrogens. This would permit longer exposure times to the carcinogenic metabolites of E(2) and chronic exposure to oxidant stress as a result of metabolic redox cycling to estrogen metabolites, and thus quercetin may exacerbate E(2

  3. Quercetin-3-O-glucuronide promotes the proliferation and migration of neural stem cells.

    PubMed

    Baral, Samrat; Pariyar, Ramesh; Kim, Jaehyo; Lee, Ho-Sub; Seo, Jungwon

    2017-04-01

    Quercetin is a bioactive compound exerting therapeutic effects on in vivo animal models of neurodegeneration or neurotoxicity. However, the narrow therapeutic dose-range of quercetin has been a point of concern since previous studies have demonstrated that quercetin induces cytotoxicity in vitro. Quercetin is metabolized to quercetin glucuronates such as quercetin-3-O-glucuronide (Q3GA), primarily detected in the plasma and the brain. Here, we examined whether and how quercetin or Q3GA regulates neural stem cells (NSCs) in vivo and in vitro. Immunohistochemistry showed that oral administration of quercetin increased nestin-, DCX-, BrdU/DCX-, and BrdU/NeuN-positive cells in the dentate gyrus of mice. However, quercetin decreased the viability of human embryonic NSCs in culture, accompanied by decreased Akt phosphorylation and increased cleavage of caspase-3 and PARP. In contrast, Q3GA increased BrdU-positive cell proliferation, Akt phosphorylation, and cyclin D1 expression. PI3K/Akt inhibitor LY294002 reversed Q3GA-induced Akt phosphorylation and cyclin D1 expression, thereby reducing Q3GA-induced proliferation. Furthermore, Q3GA increased the protein secretion of BDNF and its blockade using anti-BDNF antibody reversed Q3GA-induced proliferation. Under differentiation state, Q3GA promotes NSC migration, along with increased mRNA expression of CXCR4. Moreover, Q3GA significantly reversed scopolamine-induced reduction of Akt phosphorylation in the mouse hippocampus and ameliorated scopolamine-induced memory impairments. Our results demonstrate that quercetin and its metabolite Q3GA control NSC viability in a converse manner through contrary regulation of Akt, accounting for the conflicting effects of quercetin in vivo and in vitro. This study provides a novel mechanism for the positive effects of Q3GA on neurogenesis and suggests its therapeutic potential in neurodegenerative diseases.

  4. Glucuronidated Quercetin Lowers Blood Pressure in Spontaneously Hypertensive Rats via Deconjugation

    PubMed Central

    Galindo, Pilar; Rodriguez-Gómez, Isabel; González-Manzano, Susana; Dueñas, Montserrat; Jiménez, Rosario; Menéndez, Carmen; Vargas, Félix; Tamargo, Juan; Santos-Buelga, Celestino; Pérez-Vizcaíno, Francisco; Duarte, Juan

    2012-01-01

    Background Chronic oral quercetin reduces blood pressure and restores endothelial dysfunction in hypertensive animals. However, quercetin (aglycone) is usually not present in plasma, because it is rapidly metabolized into conjugated, mostly inactive, metabolites. The aim of the study is to analyze whether deconjugation of these metabolites is involved in the blood pressure lowering effect of quercetin. Methodology/Principal Findings We have analyzed the effects on blood pressure and vascular function in vitro of the conjugated metabolites of quercetin (quercetin-3-glucuronide, Q3GA; isorhamnetin-3-glucuronide, I3GA; and quercetin-3′-sulfate, Q3'S) in spontaneously hypertensive rats (SHR). Q3GA and I3GA (1 mg/kg i.v.), but not Q3'S, progressively reduced mean blood pressure (MBP), measured in conscious SHR. The hypotensive effect of Q3GA was abolished in SHR treated with the specific inhibitor of β-glucuronidase, saccharic acid 1,4-lactone (SAL, 10 mg/ml). In mesenteric arteries, unlike quercetin, Q3GA had no inhibitory effect in the contractile response to phenylephrine after 30 min of incubation. However, after 1 hour of incubation Q3GA strongly reduced this contractile response and this effect was prevented by SAL. Oral administration of quercetin (10 mg/Kg) induced a progressive decrease in MBP, which was also suppressed by SAL. Conclusions Conjugated metabolites are involved in the in vivo antihypertensive effect of quercetin, acting as molecules for the plasmatic transport of quercetin to the target tissues. Quercetin released from its glucuronidated metabolites could be responsible for its vasorelaxant and hypotensive effect. PMID:22427863

  5. Modulation of BV-2 microglia functions by novel quercetin pivaloyl ester.

    PubMed

    Mrvová, Nataša; Škandík, Martin; Kuniaková, Marcela; Račková, Lucia

    2015-11-01

    Chronic inflammation in brain plays a critical role in major neurodegenerative diseases such as Alzheimer's, Parkinson's disease, stroke or multiple sclerosis. Microglia, resident macrophages and intristinc components of CNS, appear to be main effectors in this pathological process. Quercetin, a naturally occurring flavonoid, was proven to downregulate inflammatory genes in microglia. Synthetically modified quercetin, 3'-O-(3-chloropivaloyl) quercetin (CPQ), is assumed to possess better biological availability and enhanced antioxidant properties. In the present study, antineuroinflammatory capability of the novel compound CPQ was assessed in BV-2 microglial cells. Our data show that treatment with CPQ attenuated the production of the inflammatory mediators, nitric oxide (NO) and tumour necrosis factor-α (TNF-α), in LPS-stimulated microglia somewhat more efficiently than did quercetin (p > 0.05 for CPQ vs. quercetin-treated group). Also, protein level of inducible NO synthase (iNOS) in LPS-activated BV-2 microglia was to some extent more effectively supressed by CPQ than by unmodified flavonoid. In consistence with the extent of their effects on pro-inflammatory markers, CPQ and quercetin showed down-regulation of NFκB activation. This quercetin analogue caused also a decline in BV-2 microglia proliferation with interfering with cell cycle progression (p < 0.001 for CPQ vs. quercetin-treated group). However, CPQ did not remarkably affect cell viability. In addition, CPQ showed a minor better suppression of PMA-induced generation of superoxide than did quercetin. Neither CPQ nor quercetin influenced phagocytosis of BV-2 cells. These results point to the therapeutic potential of 3'-O-(3-chloropivaloyl)quercetin (CPQ) as a novel antiinflammatory drug in neurodegenerative diseases, mediating favourable modulation of pro-inflammatory functions of microglia.

  6. Anthocyanin indexes, quercetin, kaempferol, and myricetin concentration in leaves and fruit of Abutilon theophrasti Medik. genetic resources

    USDA-ARS?s Scientific Manuscript database

    Anthocyanin indexes, quercetin, kaempferol, and myricetin may provide industry with potential new medicines or nutraceuticals. Velvetleaf (Abutilon theophrasti Medik) leaves from 42 accessions were analyzed for anthocyanin indexes while both leaves and fruit were used for quercetin, kaempferol, and ...

  7. Quercetin, kaempferol, myricetin, and fatty acid content among several Hibiscus sabdariffa accession calyces based on maturity in a greenhouse

    USDA-ARS?s Scientific Manuscript database

    Flavonols including quercetin, kaempferol, myricetin, and fatty acids in plants have many useful health attributes including antioxidants, cholesterol lowering, and cancer prevention. Six accessions of roselle, Hibiscus sabdariffa calyces were evaluated for quercetin, kaempferol, and myricetin conte...

  8. Lecithin-based novel cationic nanocarriers (Leciplex) II: improving therapeutic efficacy of quercetin on oral administration.

    PubMed

    Date, Abhijit A; Nagarsenker, Mangal S; Patere, Shilpa; Dhawan, Vivek; Gude, R P; Hassan, P A; Aswal, V; Steiniger, Frank; Thamm, Jana; Fahr, Alfred

    2011-06-06

    The objective of the present investigation was to evaluate ability of the novel self-assembled phospholipid- based cationic nanocarriers (LeciPlex) in improving the therapeutic efficacy of a poorly water-soluble natural polyphenolic agent, quercetin (QR), on oral administration. Quercetin loaded LeciPlex (QR-LeciPlex) were successfully fabricated using a biocompatible solvent Transcutol HP. The QR-LeciPlex were characterized for particle size, encapsulation efficiency, zeta potential, and particle morphology by cryo-TEM. UV and fluorescence spectral characterization was carried out to find out the association of QR with LeciPlex. Small angle neutron scattering studies (SANS) were carried out to understand the internal structure of Leciplex and to evaluate the influence of the incorporation of QR in the LeciPlex. Anti-inflammatory and antitumorigenic activity of QR-LeciPlex was determined in comparison to QR suspension to evaluate the potential of LeciPlex in improving oral delivery of QR. QR-LeciPlex exhibited a particle size of ∼400 nm and had excellent colloidal stability. The QR-LeciPlex had a zeta potential greater than +30 mV and exhibited very high encapsulation efficiency of QR (>90%). UV and fluorescence spectral characterization indicated the interaction/association of QR with LeciPlex components. Cryo-TEM studies showed that LeciPlex and QR-LeciPlex have a unilamellar structure. SANS confirmed the unilamellar structure of LeciPlex and indicated that the incorporation of QR does not have any effect on the internal structure of the LeciPlex. QR-LeciPlex exhibited significantly higher anti-inflammatory and antitumorigenic activity (p < 0.01) as compared to that of QR suspension on oral administration.

  9. Genetic expression profile analysis of the temporal inhibition of quercetin and naringenin on Lactobacillus rhamnosus GG

    USDA-ARS?s Scientific Manuscript database

    The plant polyphenols, quercetin and naringenin, are considered healthy dietary compounds; however, little is known of their effects on the probiotic Lactobacillus rhamnosus GG (LGG). In this study, it was discovered that both quercetin and naringenin produced temporary inhibition of LGG growth, par...

  10. Microsomal quercetin glucuronidation in rat small intestine depends on age and segment

    USDA-ARS?s Scientific Manuscript database

    UDP-glucuronosyltransferase (UGT) activity toward the flavonoid quercetin and UGT protein were characterized in 3 equidistant small intestine (SI) segments from 4, 12, 18, and 28 mo male F344 rats, n=8/age using villin to control for enterocyte content. SI microsomal intrinsic clearance of quercetin...

  11. Effects of quercetin on pharmacokinetics of cefprozil in Chinese-Han male volunteers.

    PubMed

    Jia, Fei-Fei; Tan, Zhi-Rong; McLeod, Howard L; Chen, Yao; Ou-Yang, Dong-Sheng; Zhou, Hong-Hao

    2016-10-01

    1. The primary objective of this study was to evaluate the effects of quercetin on the pharmacokinetics of cefprozil. The secondary objective was to evaluate the safety of the combined use of cefprozil and quercetin. 2. An open-label, two-period, crossover phase I trial among 24 Han Chinese male subjects was conducted. Participants were given 500 mg of quercetin orally once daily for 15 d followed by single dose of cefprozil (500 mg) on day 15. Serum concentrations of cefprozil were then measured in all participants on day 15. A 15-d washout period was then assigned after which a 500 mg dose of cefprozil was administered and measured in the serum on day 36. 3. All subjects completed the trial, and no serious adverse events were reported. We measured mean serum concentrations of cefprozil in the presence and absence of quercetin in all participants. The maximum serum concentration of cefprozil in the presence of quercetin was 8.18 ug/ml (95% CI: 7.55-8.81) versus a maximum cefprozil concentration of 8.35 ug/ml (95% CI: 7.51-9.19) in the absence of quercetin. We conclude that the concurrent use of quercetin has no substantial effect on serum concentrations of orally administered cefprozil. 4. Co-administration of quercetin showed no statistically significant effects on the pharmacokinetics of cefprozil in healthy Chinese subjects.

  12. Bioactive effects of quercetin in the central nervous system: Focusing on the mechanisms of actions.

    PubMed

    Suganthy, Natarajan; Devi, Kasi Pandima; Nabavi, Seyed Fazel; Braidy, Nady; Nabavi, Seyed Mohammad

    2016-12-01

    Quercetin, a ubiquitous flavonoid that is widely distributed in plants is classified as a cognitive enhancer in traditional and oriental medicine. The protective effects of quercetin for the treatment of neurodegenerative disorders and cerebrovascular diseases have been demonstrated in both in vitro and in vivo studies. The free radical scavenging activity of quercetin has been well-documented, wherein quercetin has been observed to exhibit protective effects against oxidative stress mediated neuronal damage by modulating the expression of NRF-2 dependent antioxidant responsive elements, and attenuation of neuroinflammation by suppressing NF-κB signal transducer and activator of transcription-1 (STAT-1). Several in vitro and in vivo studies have also shown that quercetin destabilizes and enhances the clearance of abnormal protein such as beta- amyloid peptide and hyperphosphorlyated tau, the key pathological hallmarks of Alzheimer's disease. Quercetin enhances neurogenesis and neuronal longevity by modulating a broad number of kinase signaling cascades such as phophoinositide 3- kinase (P13-kinase), AKT/PKB tyrosine kinase and Protein kinase C (PKC). Quercetin has also been well reported for its ability to reverse cognitive impairment and memory enhancement during aging. The current review focuses on summarizing the recent findings on the neuroprotective effect of quercetin, its mechanism of action and its possible roles in the prevention of neurological disorders.

  13. Association of Dietary Quercetin with Reduced Risk of Proximal Colon Cancer

    PubMed Central

    Djuric, Zora; Severson, Richard K.; Kato, Ikuko

    2012-01-01

    Quercetin is a flavonol that appears to be protective against several cancers, but its possible role in prevention of colorectal cancer is not yet well studied. We evaluated dietary intakes of quercetin and risk of colorectal cancer in a large case-control study conducted in Metropolitan Detroit, MI (n = 2664). The protective effects of quercetin intake, as assessed by food frequency questionnaire, were confined to risk of proximal colon cancer. Stratified analyses showed that the protective effects of quercetin on risk of proximal colon cancer were significant only when fruit intake or the Healthy Eating Index score were high, or when tea intake was low, with odds ratios (OR) for the highest versus the lowest quartile = 0.49, 0.44, and 0.51, respectively. Increased quercetin intake had no protective effects when tea intake was high. Interestingly, increased intake of quercetin was associated with increased risk of distal colon cancer when total fruit intake was low (OR for the highest versus the lowest quartile = 1.99). These results suggest that quercetin can have disparate effects on colon cancer risk depending on whether dietary intakes of fruit or tea are high, and that quercetin had protective effects only on proximal, not distal, colon cancer. PMID:22429001

  14. The flavonoid quercetin induces apoptosis and inhibits JNK activation in intimal vascular smooth muscle cells

    SciTech Connect

    Perez-Vizcaino, Francisco . E-mail: fperez@med.ucm.es; Bishop-Bailley, David; Lodi, Federica; Duarte, Juan; Cogolludo, Angel; Moreno, Laura; Bosca, Lisardo; Mitchell, Jane A.; Warner, Timothy D.

    2006-08-04

    Quercetin, the most abundant dietary flavonol, exerts vasodilator, anti-hypertensive, and anti-atherogenic effects and reduces the vascular remodelling associated with elevated blood pressure. Here, we have compared the effects of quercetin in intimal- and medial-type rat vascular smooth muscle cells (VSMC) in culture. After 48 h, quercetin reduced the viability of a polyclonal intimal-type cell line derived from neonatal aorta but not of a medial-type cell line derived from adult aorta. These differential effects were similar in both proliferating and quiescent VSMC. Quercetin also preferentially reduced the viability of intimal-type over medial-type VSMC in primary cultures derived from balloon-injured carotid arteries. The effects of quercetin on cell viability were mainly dependent upon induction of apoptosis, as demonstrated by nuclear condensation and fragmentation, and were unrelated to PPAR{gamma}, pro-oxidant effects or nitric oxide. The expression of MAPKs (ERK, p38, and JNK) and ERK phosphorylation were not different between intimal- and medial-type VSMC. p38 phosphorylation was negligible in both cell types. Medial-type showed a weak JNK phosphorylation while this was markedly increased in intimal-type cells. Quercetin reduced JNK phosphorylation but had no consistent effect on ERK phosphorylation. In conclusion, quercetin preferentially produced apoptosis in intimal-type compared to medial-type VSMC. This might play a role in the anti-atherogenic and anti-hypertensive effects of quercetin.

  15. Quercetin induces mitochondrial mediated apoptosis and protective autophagy in human glioblastoma U373MG cells.

    PubMed

    Kim, Hyeonji; Moon, Jeong Yong; Ahn, Kwang Seok; Cho, Somi Kim

    2013-01-01

    Quercetin is a dietary flavonoid with known antitumor effects against several types of cancers by promoting apoptotic cell death and inducing cell cycle arrest. However, U373MG malignant glioma cells expressing mutant p53 are resistant to a 24 h quercetin treatment. In this study, the anticancer effect of quercetin was reevaluated in U373MG cells, and quercetin was found to be significantly effective in inhibiting proliferation of U373MG cells in a concentration-dependent manner after 48 and 72 h of incubation. Quercetin induced U373MG cell death through apoptosis, as evidenced by the increased number of cells in the sub-G1 phase, the appearance of fragmented nuclei, decreased mitochondrial membrane potential, proteolytic activation of caspase-3 and caspase-7, an increase in caspase-3 and 9 activities, and degradation of poly(ADP-ribose) polymerase protein. Furthermore, quercetin activated JNK and increased the expression of p53, which translocated to the mitochondria and simultaneously led to the release of cytochrome c from mitochondria to the cytosol. We also found that quercetin induced autophagy. Pretreatment with chloroquine, an autophagy inhibitor, strongly augmented apoptosis in U373MG cells, indicating that quercetin induced protective autopagy in U373MG cells.

  16. The flavonoid quercetin induces apoptosis and inhibits JNK activation in intimal vascular smooth muscle cells.

    PubMed

    Perez-Vizcaino, Francisco; Bishop-Bailley, David; Lodi, Federica; Duarte, Juan; Cogolludo, Angel; Moreno, Laura; Bosca, Lisardo; Mitchell, Jane A; Warner, Timothy D

    2006-08-04

    Quercetin, the most abundant dietary flavonol, exerts vasodilator, anti-hypertensive, and anti-atherogenic effects and reduces the vascular remodelling associated with elevated blood pressure. Here, we have compared the effects of quercetin in intimal- and medial-type rat vascular smooth muscle cells (VSMC) in culture. After 48 h, quercetin reduced the viability of a polyclonal intimal-type cell line derived from neonatal aorta but not of a medial-type cell line derived from adult aorta. These differential effects were similar in both proliferating and quiescent VSMC. Quercetin also preferentially reduced the viability of intimal-type over medial-type VSMC in primary cultures derived from balloon-injured carotid arteries. The effects of quercetin on cell viability were mainly dependent upon induction of apoptosis, as demonstrated by nuclear condensation and fragmentation, and were unrelated to PPARgamma, pro-oxidant effects or nitric oxide. The expression of MAPKs (ERK, p38, and JNK) and ERK phosphorylation were not different between intimal- and medial-type VSMC. p38 phosphorylation was negligible in both cell types. Medial-type showed a weak JNK phosphorylation while this was markedly increased in intimal-type cells. Quercetin reduced JNK phosphorylation but had no consistent effect on ERK phosphorylation. In conclusion, quercetin preferentially produced apoptosis in intimal-type compared to medial-type VSMC. This might play a role in the anti-atherogenic and anti-hypertensive effects of quercetin.

  17. Quercetin induces necrosis and apoptosis in SCC-9 oral cancer cells.

    PubMed

    Haghiac, Maricela; Walle, Thomas

    2005-01-01

    Evidence has accumulated that dietary polyphenols, in particular, flavonoids, have protective effects against oral cancer. In this study, we have examined the effects of quercetin, a major dietary flavonoid, on cell growth and necrosis/apoptosis and cell cycle regulation in human oral squamous carcinoma SCC-9 cells. Quercetin induced dose- and time-dependent, irreversible inhibition of cell growth and cellular DNA synthesis. Light microscopy and lactate dehydrogenase measurements showed modifications in the morphology and membrane integrity of these cells after quercetin treatment. Propidium iodide/annexin V staining showed that quercetin induced necrosis at 24 h and 48 h, whereas at 72 h cells underwent apoptosis, correlating with caspase-3 activation. Flow cytometry studies of the cell cycle distribution showed that quercetin induced mainly S-phase arrest. Thymidylate synthase (TS), a key S-phase enzyme, was inhibited in a time- and dose-dependent fashion by quercetin at the protein level. A lack of effect on TS mRNA suggested that TS down-regulation occurred at the translational level. In conclusion, our data support a view that quercetin initially induces a stress response, resulting in necrosis of these oral epithelial cells. Prolonged exposure of the surviving cells to quercetin causes apoptosis, presumably mediated by inhibition of TS protein.

  18. Quercetin Induces Mitochondrial Mediated Apoptosis and Protective Autophagy in Human Glioblastoma U373MG Cells

    PubMed Central

    Moon, Jeong Yong; Ahn, Kwang Seok; Cho, Somi Kim

    2013-01-01

    Quercetin is a dietary flavonoid with known antitumor effects against several types of cancers by promoting apoptotic cell death and inducing cell cycle arrest. However, U373MG malignant glioma cells expressing mutant p53 are resistant to a 24 h quercetin treatment. In this study, the anticancer effect of quercetin was reevaluated in U373MG cells, and quercetin was found to be significantly effective in inhibiting proliferation of U373MG cells in a concentration-dependent manner after 48 and 72 h of incubation. Quercetin induced U373MG cell death through apoptosis, as evidenced by the increased number of cells in the sub-G1 phase, the appearance of fragmented nuclei, decreased mitochondrial membrane potential, proteolytic activation of caspase-3 and caspase-7, an increase in caspase-3 and 9 activities, and degradation of poly(ADP-ribose) polymerase protein. Furthermore, quercetin activated JNK and increased the expression of p53, which translocated to the mitochondria and simultaneously led to the release of cytochrome c from mitochondria to the cytosol. We also found that quercetin induced autophagy. Pretreatment with chloroquine, an autophagy inhibitor, strongly augmented apoptosis in U373MG cells, indicating that quercetin induced protective autopagy in U373MG cells. PMID:24379902

  19. Quercetin induces gadd45 expression through a p53-independent pathway.

    PubMed

    Yoshida, Tatsushi; Maeda, Ayaka; Horinaka, Mano; Shiraishi, Takumi; Nakata, Susumu; Wakada, Miki; Yogosawa, Shingo; Sakai, Toshiyuki

    2005-11-01

    Quercetin, a kind of flavonoid, is found in edible fruits and vegetables and has anti-tumorigenic activity. However, the mechanism of activity has not been elucidated. We show for the first time that gadd45 is a molecular target of quercetin, which inhibits growth of human cervical cancer HeLa cells. Apoptosis was detected in HeLa cells treated with quercetin. At the concentration inducing apoptosis, quercetin also increased gadd45 expression at the mRNA and protein level, however, the 5'-promoter region of the gadd45 gene was not activated by quercetin. Since gadd45 is known to be a downstream gene of the tumor suppressor p53, we examined whether or not quercetin regulates gadd45 induction via a p53 pathway. Quercetin did not activate transcription through p53-binding sites in HeLa cells, although it up-regulated gadd45 in p53-inactivated tumor cells. These results indicate that quercetin induces gadd45 expression in a p53-independent manner.

  20. The flavonoid quercetin induces acute vasodilator effects in healthy volunteers: correlation with beta-glucuronidase activity.

    PubMed

    Perez, Almudena; Gonzalez-Manzano, Susana; Jimenez, Rosario; Perez-Abud, Rocío; Haro, Jose M; Osuna, Antonio; Santos-Buelga, Celestino; Duarte, Juan; Perez-Vizcaino, Francisco

    2014-11-01

    Quercetin exerts vasodilator, antiplatelet and antiproliferative effects and reduces blood pressure, oxidative status and end-organ damage in hypertensive humans and animal models. We hypothesized that oral quercetin might induce vasodilator effects in humans and that they might be related to the deconjugation of quercetin-3-O-glucuronide (Q3GA). double blind, randomized, placebo-controlled trial. Fifteen healthy volunteers (26±5 years, 6 female) were given a capsule containing placebo, 200 or 400mg of quercetin in random order in three consecutive weeks. At 2h a dose-dependent increase in Q3GA was observed in plasma (∼0.4 and 1μM for 200 and 400mg, respectively) with minor levels of quercetin and isorhamnetin. No changes were observed in blood pressure. At 5h quercetin induced and increase in brachial arterial diameter that correlated with the product of the levels of Q3GA by the plasma glucuronidase activity. There was an increase in urinary levels of glutathione but there was no increase in nitrites plus nitrates. Quercetin and isorhamnetin also relaxed human umbilical arteries in vitro while Q3GA was without effect. In conclusions, quercetin exerts acute vasodilator effects in vivo in normotensive, normocholesterolemic human subjects. These results are consistent with the effects being due to the deconjugation of the metabolite Q3GA. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Quercetin suppresses intracellular ROS formation, MMP activation, and cell motility in human fibrosarcoma cells.

    PubMed

    Lee, Dong Eun; Chung, Min-Yu; Lim, Tae Gyu; Huh, Won Bum; Lee, Hyong Joo; Lee, Ki Won

    2013-09-01

    Cell metastasis is a major cause of death from cancer and can arise from excessive levels of oxidative stress. The objective of this study was to investigate whether the natural flavonoid quercetin can inhibit matrix metalloproteinase (MMP)-2 and -9 activities through the attenuation of reactive oxygen species (ROS) formation, an event expected to lead to the inhibition of cell motility. To induce sustained ROS formation, cells were treated with phenazine methosulfate (PMS; 1 μM). Noncytotoxic concentrations of quercetin inhibited PMS-induced increases in cell motility in HT1080 human fibrosarcoma (HT1080) cells. While nearly 100% of cells were observed to migrate after 24 h of PMS treatment, quercetin significantly (P < 0.01) suppressed this effect. We also found that quercetin, up to 10 μg/mL, attenuated PMS-induced MMP-2 activation. We then investigated whether the decreased levels of MMP-2 activation could be attributable to lower levels of ROS formation by quercetin. We found that quercetin treatments significantly attenuated PMS-induced ROS formation (P < 0.01) and resulted in decreased cell motility associated with a reduction in MMP-2 and -9 activitiy in HT1080 cells, even in the absence of PMS treatment. Collectively, these results suggest that quercetin inhibits cell motility via the inhibition of MMP activation in HT1080 cells in the presence and absence of PMS. This is likely to be a result of the suppression of intracellular ROS formation by quercetin. © 2013 Institute of Food Technologists®

  2. The flavonoid quercetin inhibits dimethylnitrosamine-induced liver damage in rats.

    PubMed

    Lee, Eun-Sil; Lee, Hye-Eun; Shin, Ji-Young; Yoon, Sik; Moon, Jeon-Ok

    2003-08-01

    Quercetin, one of the most abundant flavonoids in human diet has been reported to exhibit a wide range of pharmacological properties. In this study, we investigated the protective effect of quercetin on hepatic injury induced by dimethylnitrosamine (DMN) in rats. Treatment with DMN caused a significant decrease in body and liver weight. Oral administration of quercetin (10 mg kg(-1) daily for 4 weeks) remarkably prevented this DMN-induced loss in body and liver weight and inhibited the elevation of serum alanine transaminase, aspartate transaminase and bilirubin levels. Quercetin also increased serum albumin and hepatic glutathione levels and reduced the hepatic level of malondialdehyde. Furthermore, DMN-induced elevation of hydroxyproline content was reduced in the quercetin treated rats, the result of which was consistent with a reduction in type I collagen mRNA production and histological analysis of liver tissue stained with Sirius red. A reduction in hepatic stellate cell activation, as assessed by alpha-smooth muscle actin staining, was associated with quercetin treatment as well as a reduction in transforming growth factor-beta1 expression. In conclusion, these results demonstrate that quercetin exhibited in-vivo hepatoprotective and anti-fibrogenic effects against DMN-induced liver injury and suggest that quercetin may be useful in the preventing the development of hepatic fibrosis.

  3. Protective role of quercetin against cisplatin-induced hair cell damage in zebrafish embryos.

    PubMed

    Lee, S K; Oh, K H; Chung, A Y; Park, H C; Lee, S H; Kwon, S Y; Choi, J

    2015-11-01

    The aim of this study was to evaluate the protective effects of quercetin on cisplatin-induced hair cell damage in transgenic zebrafish embryos. Five days postfertilization zebrafish embryos were exposed to 1 mM cisplatin and quercetin at 10, 50, 100, or 200 μM for 4 h. Hair cells within neuromasts of the supraorbital, otic, and occipital lateral lines were analyzed by fluorescent microscopy (n = 10). Survival of hair cells was calculated as the average number of hair cells in the control group that were not exposed to cisplatin. Ultrastructural changes were evaluated using scanning electron microscopy. Hair cell damage in neuromasts was decreased by co-treatment of quercetin and cisplatin (quercetin 100 μM: 8.6 ± 1.1 cells; 1 mM cisplatin only: 5.0 ± 0.5 cells; n = 10, p < 0.05); apoptosis of hair cells examined by special stain was also decreased by quercetin. The ultrastructure of hair cells within neuromasts was preserved in zebrafish by the combination of quercetin (100 μM) and cisplatin (1 mM). In conclusion, quercetin showed protective effects against cisplatin-induced toxicity in a zebrafish model. The results of this study suggest the possibility of a protective role of quercetin against cisplatin-induced apoptotic cell death in zebrafish. © The Author(s) 2015.

  4. Quercetin-3-methyl ether suppresses proliferation of mouse epidermal JB6 P+ cells by targeting ERKs

    PubMed Central

    Mottamal, Madhusoodanan; Liu, Kangdong; Zhu, Feng; Cho, Yong-Yeon; Sosa, Carlos P.; Zhou, Keyuan; Bowden, G.Tim; Bode, Ann M.; Dong, Zigang

    2012-01-01

    Chemoprevention has been acknowledged as an important and practical strategy for the management of skin cancer. Quercetin-3-methyl ether, a naturally occurring compound present in various plants, has potent anticancer-promoting activity. We identified this compound by in silico virtual screening of the Traditional Chinese Medicine Database using extracellular signal-regulated kinase 2 (ERK2) as the target protein. Here, we showed that quercetin-3-methyl ether inhibited proliferation of mouse skin epidermal JB6 P+ cells in a dose- and time-dependent manner by inducing cell cycle G2–M phase accumulation. It also suppressed 12-O-tetradecanoylphorbol-13-acetate-induced neoplastic cell transformation in a dose-dependent manner. Its inhibitory effect was greater than quercetin. The activation of activator protein-1 was dose-dependently suppressed by quercetin-3-methyl ether treatment. Western blot and kinase assay data revealed that quercetin-3-methyl ether inhibited ERKs kinase activity and attenuated phosphorylation of ERKs. Pull-down assays revealed that quercetin-3-methyl ether directly binds with ERKs. Furthermore, a loss-of-function ERK2 mutation inhibited the effectiveness of the quercetin-3-methyl ether. Overall, these results indicated that quercetin-3-methyl ether exerts potent chemopreventive activity by targeting ERKs. PMID:22139441

  5. Secretory leukoprotease inhibitor is required for efficient quercetin-mediated suppression of TNFα secretion

    PubMed Central

    Serino, Grazia; Galleggiante, Vanessa; Caruso, Maria Lucia; Mastronardi, Mauro; Cavalcanti, Elisabetta; Ranson, Nicole; Pinto, Aldo; Campiglia, Pietro; Santino, Angelo

    2016-01-01

    Dendritic cells (DCs) are professional antigen presenting cells (APCs) that in response to microbial infections generate long-lasting adaptive immune response. Following microbial uptake, DCs undergo a cascade of cellular differentiation that ultimately leads to “mature” DCs. Mature DCs produce a variety of inflammatory cytokines, including tumor necrosis factor-α (TNFα) a key cytokine for the inflammatory cascade. In numerous studies, polyphenols, including quercetin, demonstrated their ability to suppress TNFα secretion and protect from the onset of chronic inflammatory disorders. We show that murine bone marrow derived DCs express Slpi following quercetin exposure. Slpi is known to suppress LPS mediated NFκB activation, thus, it was hypothesized that its expression could be the key step for polyphenol induced inflammatory suppression. Slpi-KO DCs poorly respond to quercetin administration failing to reduce TNFα secretion in response to quercetin exposure. Supernatant from quercetin exposed DCs could also reduce LPS-mediated TNFα secretion by unrelated DCs, but this property is lost using an anti-Slpi antibody. In vivo, oral administration of quercetin is able to induce Slpi expression. Human biopsies from inflamed tract of the intestine reveal the presence of numerous SLPI+ cells and the expression level could be further increased by quercetin administration. We propose that quercetin induces Slpi expression that in turn reduces the inflammatory response. Our data encourages the development of nutritional strategies to improve the efficiency of current therapies for intestinal chronic inflammatory syndrome and reduce the risks of colorectal cancer development. PMID:27716626

  6. Preventive effect of dietary quercetin on disuse muscle atrophy by targeting mitochondria in denervated mice.

    PubMed

    Mukai, Rie; Matsui, Naoko; Fujikura, Yutaka; Matsumoto, Norifumi; Hou, De-Xing; Kanzaki, Noriyuki; Shibata, Hiroshi; Horikawa, Manabu; Iwasa, Keiko; Hirasaka, Katsuya; Nikawa, Takeshi; Terao, Junji

    2016-05-01

    Quercetin is a major dietary flavonoid in fruits and vegetables. We aimed to clarify the preventive effect of dietary quercetin on disuse muscle atrophy and the underlying mechanisms. We established a mouse denervation model by cutting the sciatic nerve in the right leg (SNX surgery) to lack of mobilization in hind-limb. Preintake of a quercetin-mixed diet for 14days before SNX surgery prevented loss of muscle mass and atrophy of muscle fibers in the gastrocnemius muscle (GM). Phosphorylation of Akt, a key phosphorylation pathway of suppression of protein degradation, was activated in the quercetin-mixed diet group with and without SNX surgery. Intake of a quercetin-mixed diet suppressed the generation of hydrogen peroxide originating from mitochondria and elevated mitochondrial peroxisome proliferator-activated receptor-γ coactivator 1α mRNA expression as well as NADH dehydrogenase 4 expression in the GM with SNX surgery. Quercetin and its conjugated metabolites reduced hydrogen peroxide production in the mitochondrial fraction obtained from atrophied muscle. In C2C12 myotubes, quercetin reached the mitochondrial fraction. These findings suggest that dietary quercetin can prevent disuse muscle atrophy by targeting mitochondria in skeletal muscle tissue through protecting mitochondria from decreased biogenesis and reducing mitochondrial hydrogen peroxide release, which can be related to decreased hydrogen peroxide production and/or improvements on antioxidant capacity of mitochondria. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. The effect of quercetin on genetic expression of the commensal gut microbes bifidobacterium catenulatum, enterococcus caccae and ruminococcus gauvreauii

    USDA-ARS?s Scientific Manuscript database

    Quercetin is one of the most abundant polyphenols found in fruits and vegetables. The ability of the gut microbiota to metabolize quercetin has been previously documented; however, the effect that quercetin may have on commensal gut microbes remains unclear. In the present study, the effects of que...

  8. The flavonoid quercetin transiently inhibits the activity of taxol and nocodazole through interference with the cell cycle

    PubMed Central

    Samuel, Temesgen; Fadlalla, Khalda; Turner, Timothy; Yehualaeshet, Teshome E.

    2010-01-01

    Quercetin is a flavonoid with anticancer properties. In this study, we examined the effects of quercetin on cell cycle, viability and proliferation of cancer cells, either singly or in combination with the microtubule-targeting drugs taxol and nocodazole. Although quercetin induced cell death in a dose dependent manner, 12.5-50μM quercetin inhibited the activity of both taxol and nocodazole to induce G2/M arrest in various cell lines. Quercetin also partially restored drug-induced loss in viability of treated cells for up to 72 hours. This antagonism of microtubule-targeting drugs was accompanied by a delay in cell cycle progression and inhibition of the buildup of cyclin-B1 at the microtubule organizing center of treated cells. However, quercetin did not inhibit the microtubule targeting of taxol or nocodazole. Despite the short-term protection of cells by quercetin, colony formation and clonogenicity of HCT116 cells were still suppressed by quercetin or quercetin-taxol combination. The status of cell adherence to growth matrix was critical in determining the sensitivity of HCT116 cells to quercetin. We conclude that while long-term exposure of cancer cells to quercetin may prevent cell proliferation and survival, the interference of quercetin with cell cycle progression diminishes the efficacy of microtubule-targeting drugs to arrest cells at G2/M. PMID:21058190

  9. The flavonoid quercetin transiently inhibits the activity of taxol and nocodazole through interference with the cell cycle.

    PubMed

    Samuel, Temesgen; Fadlalla, Khalda; Turner, Timothy; Yehualaeshet, Teshome E

    2010-01-01

    Quercetin is a flavonoid with anticancer properties. In this study, we examined the effects of quercetin on cell cycle, viability, and proliferation of cancer cells, either singly or in combination with the microtubule-targeting drugs taxol and nocodazole. Although quercetin induced cell death in a dose-dependent manner, 12.5-50 μM quercetin inhibited the activity of both taxol and nocodazole to induce G2/M arrest in various cell lines. Quercetin also partially restored drug-induced loss in viability of treated cells for up to 72 h. This antagonism of microtubule-targeting drugs was accompanied by a delay in cell cycle progression and inhibition of the buildup of cyclin-B1 at the microtubule organizing center of treated cells. However, quercetin did not inhibit the microtubule targeting of taxol or nocodazole. Despite the short-term protection of cells by quercetin, colony formation and clonogenicity of HCT116 cells were still suppressed by quercetin or quercetin-taxol combination. The status of cell adherence to growth matrix was critical in determining the sensitivity of HCT116 cells to quercetin. We conclude that although long-term exposure of cancer cells to quercetin may prevent cell proliferation and survival, the interference of quercetin with cell cycle progression diminishes the efficacy of microtubule-targeting drugs to arrest cells at G2/M.

  10. Ruminal degradation of quercetin and its influence on fermentation in ruminants.

    PubMed

    Berger, L M; Blank, R; Zorn, F; Wein, S; Metges, C C; Wolffram, S

    2015-08-01

    The aim of the present study was to investigate the ruminal degradation of the flavonol quercetin and to determine its potential antimicrobial effects on ruminal fermentation in cows. Ruminal degradation of quercetin (0 or 100μmol/L, respectively) as well as its influence on ruminal gas production (0, 50, or 100μmol of quercetin equivalents/L, respectively, either applied as aglycone or as its glucorhamnoside rutin) using concentrate, grass hay, and straw as substrates were investigated in vitro using the Hohenheim gas test. Additionally, the influence of quercetin on ruminal concentrations of volatile fatty acids and their molar ratio in rumen-fistulated, nonlactating cows (n=5) after intraruminal application of quercetin as aglycone or as rutin (0, 10, or 50mg of quercetin equivalents/kg of BW, respectively) was evaluated. Quercetin was rapidly and extensively degraded, whereby the disappearance of quercetin was accompanied by the simultaneous appearance of 2metabolites 3,4-dihydroxyphenylacetic acid and 4-methylcatechol. In vitro total gas and methane production were not reduced by the addition of quercetin aglycone or rutin, respectively, using concentrate, grass hay, and straw as substrates. As expected, however, effects of the substrates used were detected on total gas and methane production. Highest gas production was found with concentrate, whereas values obtained with grass hay and straw were lower. Relative methane production was highest with grass hay compared with concentrate and straw (27.1 vs. 25.0 and 25.5%). After intraruminal application of the quercetin aglycone or rutin, respectively, neither total concentration nor the molar ratio of volatile fatty acids in the rumen fluid were influenced. Results of the present study show that quercetin underlies rapid ruminal degradation, whereby 3,4-dihydroxyphenylacetic acid and 4-methylcatechol are the main metabolites, whereas the latter one most likely is formed by dehydroxylation from 3

  11. Quercetin subunit specifically reduces GlyR-mediated current in rat hippocampal neurons.

    PubMed

    Sun, Hao; Cheng, Xin-Ping; You-Ye, Zeng; Jiang, Peng; Zhou, Jiang-Ning

    2007-08-24

    Quercetin is a substance of low molecular weight found in vascular plants with a wide range of biological activities including antioxidative and anti-inflammatory activities. In the present study, the effects of quercetin on native glycine receptors (GlyRs) in cultured rat hippocampal neurons were investigated using a whole-cell patch-clamp technique. Quercetin reversibly and concentration-dependently depressed glycine-induced current (I(Gly)), with an IC50 of 10.7+/-0.24 microM and a Hill coefficient of 1.08+/-0.12. Quercetin depressed maximum I(Gly) and significantly changed the EC50 for glycine and the Hill coefficient. Kinetic analysis indicated that quercetin accelerated the rates of desensitization. Interestingly, after the end of glycine with quercetin coapplication, a transient rebound occurred. The quercetin effects also displayed voltage-dependence, being greater at positive membrane potentials. These effects suggested that quercetin may act as an open channel blocker. Furthermore, in the sequential application protocol, quercetin inhibited the peak amplitude of I(Gly) to a macroscopic degree while slowing GlyR desensitization. These effects implied that quercetin has a depressant effect independent of GlyR channel's opening, which maybe caused by an allosteric mechanism. Strikingly, quercetin inhibited the amplitude of recombinant-induced current mediated by alpha2-, alpha2beta-, alpha3- and alpha3beta-GlyRs but had no effects on alpha1- and alpha1beta-GlyRs that were expressed in HEK293T cells. We also investigated the effects of quercetin on I(Gly) in spinal neurons during development in vitro. The extent of blockade by quercetin on I(Gly) was slighter in spinal neurons than in hippocampal neurons in a development-dependent manner. Taken together, our results suggest that quercetin has possible effects in information processing within a neuronal network by inhibition of I(Gly) and may be useful as a pharmacological probe for identifying the subunit

  12. The effect of quercetin dietary supplementation on meat oxidation processes and texture of fattening lambs.

    PubMed

    Andrés, S; Huerga, L; Mateo, J; Tejido, M L; Bodas, R; Morán, L; Prieto, N; Rotolo, L; Giráldez, F J

    2014-02-01

    Thirty two lambs were fed a total mixed ration (TMR) formulated either with palm oil (CTRL; 34 g palm oil kg(-1) TMR) or whole flaxseed (+FS, 85 g flaxseed kg(-1) TMR) alone or enriched with quercetin (+QCT, 34 g palm oil plus 2 g quercetin kg(-1) TMR; +FS+QCT, 85 g flaxseed plus 2 g quercetin kg(-1) TMR). Dietary flaxseed did not affect, in a significant manner, the lipid peroxidation of meat samples. Quercetin treatment reduced oxysterol content (P<0.05) after 7 days of refrigerated storage of fresh meat, but did not affect significantly (P>0.05) the level of lipid-derived volatiles in the headspace of the light-exposed stored cooked meat. Sensory evaluation showed flaxseed as being responsible for a negative effect on meat flavour, probably associated with a modification of the fatty acid profile whereas, unexpectedly, quercetin seemed to worsen meat tenderisation. © 2013.

  13. Induction of apoptosis by quercetin is mediated through AMPKalpha1/ASK1/p38 pathway.

    PubMed

    Lee, Yun-Kyoung; Hwang, Jin-Taek; Kwon, Dae Young; Surh, Young-Joon; Park, Ock Jin

    2010-06-28

    Effective strategies for cancer prevention and treatment can be identified by understanding the mechanism of apoptotic pathways. In this study, we investigated the regulatory mechanism of quercetin-induced apoptosis through apoptosis signal-regulating kinase (ASK)-1 and mitogen-activated protein kinase pathways. Our results showed that quercetin increased apoptotic cell death through reactive oxygen species (ROS) generation and was responsible for ASK1 activation. Increasing ASK1 activity was accompanied by p38 activation. Interestingly, AMP-activated protein kinase (AMPK) seemed to be a critical controller of quercetin-regulated ASK1/p38 activation. Blocking AMPKalpha1 activity using Compound C, a synthetic inhibitor or siRNA showed that quercetin-activated ASK1 could not stimulate p38 activity. Thus, we suggested that quercetin-exerted apoptotic effects involve ROS/AMPKalpha1/ASK1/p38 signaling pathway, and AMPKalpha1 is a necessary element for apoptotic event induced by ASK1.

  14. Therapeutic Potential of Quercetin to Decrease Blood Pressure: Review of Efficacy and Mechanisms12

    PubMed Central

    Larson, Abigail J.; Symons, J. David; Jalili, Thunder

    2012-01-01

    Epidemiological studies beginning in the 1990s have reported that intake of quercetin, a polyphenolic flavonoid found in a wide variety of plant-based foods, such as apples, onions, berries, and red wine, is inversely related to cardiovascular disease. More recent work using hypertensive animals and humans (>140 mm Hg systolic and >90 mm Hg diastolic) indicates a decrease in blood pressure after quercetin supplementation. A number of proposed mechanisms may be responsible for the observed blood pressure decrease such as antioxidant effects, inhibition of angiotensin-converting enzyme activity, and improved endothelium-dependent and -independent function. The majority of these mechanisms have been identified using animal models treated with quercetin, and relatively few have been corroborated in human studies. The purpose of this review is to examine the evidence supporting the role of quercetin as a potential therapeutic agent and the mechanisms by which quercetin might exert its blood pressure–lowering effect. PMID:22332099

  15. A Molecularly Imprinted Polymer with Incorporated Graphene Oxide for Electrochemical Determination of Quercetin

    PubMed Central

    Sun, Si; Zhang, Mengqi; Li, Yijun; He, Xiwen

    2013-01-01

    The molecularly imprinted polymer based on polypyrrole film with incorporated graphene oxide was fabricated and used for electrochemical determination of quercetin. The electrochemical behavior of quercetin on the modified electrode was studied in detail using differential pulse voltammetry. The oxidation peak current of quercetin in B-R buffer solution (pH = 3.5) at the modified electrode was regressed with the concentration in the range from 6.0 × 10−7 to 1.5 × 10−5 mol/L (r2 = 0.997) with a detection limit of 4.8 × 10−8 mol/L (S/N = 3). This electrode showed good stability and reproducibility. In the above mentioned range, rutin or morin which has similar structures and at the same concentration as quercetin did not interfere with the determination of quercetin. The applicability of the method for complex matrix analysis was also evaluated. PMID:23698263

  16. Quercetin induces bladder cancer cells apoptosis by activation of AMPK signaling pathway.

    PubMed

    Su, Qiongli; Peng, Mei; Zhang, Yuqing; Xu, Wanjun; Darko, Kwame Oteng; Tao, Ting; Huang, Yanjun; Tao, Xiaojun; Yang, Xiaoping

    2016-01-01

    Quercetin, a natural existing polyphenol compound, has shown anticancer capacity for liver, breast, nasopharyngeal and prostate carcinoma but has not been clinically approved yet. This might be due to lack of clear mechanistic picture. Bladder cancer is one of the most common cancers of the urinary tract in the world. In China, bladder cancer has the highest rate of incidence out of all malignancies of the urinary system. The anticancer application of quercetin on bladder cancer has not been investigated either. This study was aimed to examine the mechanisms of quercetin on inhibition of bladder cancer. First, two human and one murine bladder cancer cell lines were tested in vitro for inhibitory sensitivity by MTT and cologenic assays. Second, AMPK pathway including 4E-BP1 and S6K were examined by western blot. Quercetin induces apoptosis and inhibits migration. We are the first to show that quercetin displays potent inhibition on bladder cancer cells via activation of AMPK pathway.

  17. Ultra-sonication-assisted solvent extraction of quercetin glycosides from 'Idared' apple peels.

    PubMed

    Vasantha Rupasinghe, H P; Kathirvel, Priya; Huber, Gwendolyn M

    2011-11-25

    Quercetin and quercetin glycosides are physiologically active flavonol molecules that have been attributed numerous health benefits. Recovery of such molecules from plant matrices depends on a variety of factors including polarity of the extraction solvent. Among the solvents of a wide range of dielectric constants, methanol recovered the most quercetin and its glycosides from dehydrated 'Idared' apple peels. When ultra-sonication was employed to facilitate the extraction, exposure of 15 min of ultrasound wavelengths of dehydrated apple peel powder in 80% to 100% (v/v) methanol in 1:50 (w:v) solid to solvent ratio provided the optimum extraction conditions for quercetin and its glycosides. Acidification of extraction solvent with 0.1% (v/v) or higher concentrations of HCl led to hydrolysis of naturally occurring quercetin glycosides into the aglycone as an extraction artifact.

  18. Evaluation of anti-fatigue and immunomodulating effects of quercetin in strenuous exercise mice

    NASA Astrophysics Data System (ADS)

    Zhang, Wei-qiang

    2017-04-01

    The purpose of the present study was to investigate the anti-fatigue and immunomodulating effects of quercetin in strenuous exercise mice. Mice were given orally either corn oil or quercetin (20, 40 and 60 mg/kg body weight suspended in corn oil) by gavage once a day for 28 day. All mice were sacrificed after rotarod test and the major biochemical parameters were analyzed in serum and liver. The results indicated that quercetin possessed anti-fatigue effects by prolonging retention times, decreasing levels of blood lactate and serum urea nitrogen, and increasing levels of blood glucose, tissue glycogen and serum glucagon. Furthermore, quercetin could improve the immune function of fatigue mice by decreasing tumor necrosis factor-α levels, and elevated interleukin-10 levels. Quercetin possessed anti-fatigue effects may be related to its immunomodulating effects.

  19. Synthesis, characterization and study of antioxidant activity of quercetin-magnesium complex.

    PubMed

    Ghosh, Nilanjan; Chakraborty, Tania; Mallick, Sougata; Mana, Supriya; Singha, Deepanwita; Ghosh, Balaram; Roy, Souvik

    2015-12-05

    Quercetin (3,3',4',5,7-pentahydroxyflavone) one of the most abundant dietary flavonoids, has been investigated in the presence of magnesium (II) in methanol. The complex formation between quercetin and magnesium (II) was examined under UV-visible, Infra-red and (1)H NMR spectroscopic techniques. The spectroscopic data denoted that quercetin can reacts with magnesium cation (Mg(+2)) through the chelation site in the quercetin molecule. The free radical antioxidant activity of the complex with respect to the parent molecule was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. It was observed that the free radical scavenging activity of quercetin was increased after complexation of magnesium (Mg(+2)) cation.

  20. Sensitive Voltammetric Determination of Natural Flavonoid Quercetin on a Disposable Graphite Lead

    PubMed Central

    Vu, Dai Long; Žabčíková, Simona; Ertek, Bensu; Dilgin, Yusuf

    2015-01-01

    Summary In this paper, a pencil graphite electrode was pretreated using chronoamperometry technique in phosphate buffer solution (pH=7.0) for sensitive determination of quercetin. Oxidation of quercetin was investigated using pretreated pencil graphite electrode and anodic stripping differential pulse voltammetry. Under optimal conditions, the anodic current of quercetin exhibited linear response to its concentration in the range from 0.001 to 1.5 µmol/L with the limit of detection of 0.3·10–3 µmol/L. The proposed method was successfully applied for the determination of quercetin in cranberry and blackcurrant juices with recovery rate from 93.2 to 94.7%. Solid-phase extraction was found to be necessary prior to voltammetric determination of quercetin in fruit juice samples using pretreated pencil graphite electrode. PMID:27904372

  1. Quercetin promotes neurite growth through enhancing intracellular cAMP level and GAP-43 expression.

    PubMed

    Chen, Ming-Ming; Yin, Zhi-Qi; Zhang, Lu-Yong; Liao, Hong

    2015-09-01

    The present study was designed to investigate the role of quercetin on neurite growth in N1E-115 cells and the underlying mechanisms. Quercetin was evaluated for its effects on cell numbers of neurites, neurite length, intracellular cAMP content, and Gap-43 expression in N1E-115 cells in vitro by use of microscopy, LANCE(tm) cAMP 384 kit, and Western blot analysis, respectively. Our results showed that quercetin could increase the neurite length in a concentration-dependent manner, but had no effect on the numbers of cells. Quercetin significantly increased the expression of cellular cAMP in a time- and concentration-dependent manner. The Gap-43 expression was up-regulated in a time-dependent manner. In conclusion, quercetin could promote neurite growth through increasing the intracellular cAMP level and Gap-43 expression.

  2. A molecularly imprinted polymer with incorporated graphene oxide for electrochemical determination of quercetin.

    PubMed

    Sun, Si; Zhang, Mengqi; Li, Yijun; He, Xiwen

    2013-04-25

    The molecularly imprinted polymer based on polypyrrole film with incorporated graphene oxide was fabricated and used for electrochemical determination of quercetin. The electrochemical behavior of quercetin on the modified electrode was studied in detail using differential pulse voltammetry. The oxidation peak current of quercetin in B-R buffer solution (pH = 3.5) at the modified electrode was regressed with the concentration in the range from 6.0 × 10(-7) to 1.5 × 10(-5) mol/L (r2 = 0.997) with a detection limit of 4.8 × 10(-8) mol/L (S/N = 3). This electrode showed good stability and reproducibility. In the above mentioned range, rutin or morin which has similar structures and at the same concentration as quercetin did not interfere with the determination of quercetin. The applicability of the method for complex matrix analysis was also evaluated.

  3. Quercetin induces mitochondrial biogenesis in experimental traumatic brain injury via the PGC-1α signaling pathway

    PubMed Central

    Li, Xiang; Wang, Handong; Gao, Yongyue; Li, Liwen; Tang, Chao; Wen, Guodao; Yang, Youqing; Zhuang, Zong; Zhou, Mengliang; Mao, Lei; Fan, Youwu

    2016-01-01

    Quercetin, a dietary flavonoid used as a food supplement, has been found to have protective effect against mitochondria damage after traumatic brain injury (TBI) in mice. However, the mechanisms underlying these effects are still not well understood. The aim of the present study was to investigate the effect of quercetin on the potential mechanism mediating these effects in the weight-drop model of TBI in male mice that were treated with quercetin or vehicle via intraperitoneal injection administration 30 min after TBI. Brain samples were collected 24 h later for analysis. Quercetin treatment upregulated the expression of PGC-1α and restored the level of cytochrome c, malondialdehyde (MDA) and superoxide dismutase (SOD). These results demonstrate that quercetin improves mitochondrial function in mice by improving the level of PGC-1α following TBI. PMID:27648146

  4. Quercetin induces mitochondrial biogenesis in experimental traumatic brain injury via the PGC-1α signaling pathway.

    PubMed

    Li, Xiang; Wang, Handong; Gao, Yongyue; Li, Liwen; Tang, Chao; Wen, Guodao; Yang, Youqing; Zhuang, Zong; Zhou, Mengliang; Mao, Lei; Fan, Youwu

    2016-01-01

    Quercetin, a dietary flavonoid used as a food supplement, has been found to have protective effect against mitochondria damage after traumatic brain injury (TBI) in mice. However, the mechanisms underlying these effects are still not well understood. The aim of the present study was to investigate the effect of quercetin on the potential mechanism mediating these effects in the weight-drop model of TBI in male mice that were treated with quercetin or vehicle via intraperitoneal injection administration 30 min after TBI. Brain samples were collected 24 h later for analysis. Quercetin treatment upregulated the expression of PGC-1α and restored the level of cytochrome c, malondialdehyde (MDA) and superoxide dismutase (SOD). These results demonstrate that quercetin improves mitochondrial function in mice by improving the level of PGC-1α following TBI.

  5. Evaluation of polyamidoamine dendrimers as potential carriers for quercetin, a versatile flavonoid.

    PubMed

    Madaan, Kanika; Lather, Viney; Pandita, Deepti

    2016-01-01

    The aim of the present research work was to investigate the potential of polyamidoamine (PAMAM) dendrimers as oral drug delivery carriers for quercetin, a Biopharmaceutical Classification System (BCS) class II molecule. The aqueous solubility of quercetin was investigated in different generations of dendrimers, i.e. G0, G1, G2 and G3, with varying concentrations (0.1, 0.5, 1, 2 and 4 µM). Then, it was successfully incorporated in PAMAM dendrimers and they were characterized for incorporation efficacy, nature of nanoformulations, size, size distribution, surface morphology and stability. In vitro release characteristics of quercetin from all quercetin-PAMAM complexes were studied at 37 °C in phosphate buffer saline (PBS; pH 7.4). Furthermore, the efficacy of quercetin-loaded PAMAM dendrimer was assessed by pharmacodynamic experiment, namely, a carrageenan-induced paw edema model to evaluate the acute activity of this nanocarrier in response to inflammation. It was observed that both generation and the respective concentrations of PAMAM dendrimers showed potential positive effects on solubility enhancement of quercetin. All the quercetin-PAMAM complexes were found to be in nanometeric range (<100 nm) with narrow polydispersity index. In vitro study revealed a biphasic release pattern of quercetin which was characterized by an initial faster release followed by sustained release phase and pharmacodynamic study provided the preliminary proof of concept about the potential of quercetin-PAMAM complexes. The study concludes that the dendrimer-based drug delivery system for quercetin has enormous potential to resolve the drug delivery issues associated with it.

  6. Calcium releasing action of quercetin on sarcoplasmic reticulum from frog skeletal muscle.

    PubMed

    Kurebayashi, N; Ogawa, Y

    1984-10-01

    The release of Ca by quercetin from the sarcoplasmic reticulum has been claimed to be a result of the well-known inhibition of Ca2+-ATPase activity, or to be due to an intrinsic property of quercetin. To get a clearer understanding of the effect of quercetin, we examined it using fragmented sarcoplasmic reticulum (FSR) from bullfrog skeletal muscle. The rapid phase of Ca release (hereafter simply referred to as "Ca release") from loaded FSR was almost completed within 5 s after addition of quercetin in the presence of ATP. It cannot be ascribed to the inhibition of Ca2+-ATPase activity on the basis of following findings. First, when Ca uptake was driven by carbamylphosphate, no or little Ca release was observed in marked contrast to a stronger reduction in the rate of Ca uptake. Secondly, procaine reverses the Ca releasing action of quercetin, whereas it show a synergistic action in the inhibition of Ca2+-ATPase activity. Thirdly, HFSR released more Ca than LFSR, while the Ca2+-ATPase activities of both fractions were inhibited to a similar extent. The Ca release by quercetin is enhanced by ATP or beta, gamma-methylene adenosine triphosphate, and decreased by procaine or a high concentration of Mg2+. In the presence of 2.5 mM caffeine, the amount of Ca2+ released by quercetin was decreased, and the dose-effect relationship was shifted to higher doses of quercetin. This indicates that quercetin and caffeine probably overlap in the site(s) of the action, but that quercetin is dissimilar from halothane in the mode of its Ca-releasing action.

  7. Reactive Oxygen Species Production and Mitochondrial Dysfunction Contribute to Quercetin Induced Death in Leishmania amazonensis

    PubMed Central

    Fonseca-Silva, Fernanda; Inacio, Job D. F.; Canto-Cavalheiro, Marilene M.; Almeida-Amaral, Elmo Eduardo

    2011-01-01

    Background Leishmaniasis, a parasitic disease caused by protozoa of the genus Leishmania, affects more than 12 million people worldwide. Quercetin has generated considerable interest as a pharmaceutical compound with a wide range of therapeutic activities. One such activity is exhibited against the bloodstream parasite Trypanosoma brucei and amastigotes of Leishmania donovani. However, the mechanism of protozoan action of quercetin has not been studied. Methodology/Principal Findings In the present study, we report here the mechanism for the antileishmanial activity of quercetin against Leishmania amazonensis promastigotes. Quercetin inhibited L. amazonensis promastigote growth in a dose- and time- dependent manner beginning at 48 hours of treatment and with maximum growth inhibition observed at 96 hours. The IC50 for quercetin at 48 hours was 31.4 µM. Quercetin increased ROS generation in a dose-dependent manner after 48 hours of treatment. The antioxidant GSH and NAC each significantly reduced quercetin-induced cell death. In addition, quercetin caused mitochondrial dysfunction due to collapse of mitochondrial membrane potential. Conclusions/Significance The effects of several drugs that interfere directly with mitochondrial physiology in parasites such as Leishmania have been described. The unique mitochondrial features of Leishmania make this organelle an ideal drug target while minimizing toxicity. Quercetin has been described as a pro-oxidant, generating ROS which are responsible for cell death in some cancer cells. Mitochondrial membrane potential loss can be brought about by ROS added directly in vitro or induced by chemical agents. Taken together, our results demonstrate that quercetin eventually exerts its antileishmanial effect on L. amazonensis promastigotes due to the generation of ROS and disrupted parasite mitochondrial function. PMID:21346801

  8. Quercetin phospholipid complex significantly protects against oxidative injury in ARPE-19 cells associated with activation of Nrf2 pathway.

    PubMed

    Xu, Xin-Rong; Yu, Hai-Tao; Yang, Yan; Hang, Li; Yang, Xue-Wen; Ding, Shu-Hua

    2016-01-05

    Age-related macular degeneration (AMD) is a major cause of blindness worldwide. Oxidative stress plays a crucial role in the pathogenesis of dry AMD. Quercetin has potent anti-oxidative activities, but poor bioavailability limits its therapeutic application. Herein, we prepared the phospholipid complex of quercetin (quercetin-PC), characterized its structure by differential scanning calorimetry, infrared spectrum and x-ray diffraction. Quercetin-PC had equilibrium solubility of 38.36 and 1351.27μg/ml in water and chloroform, respectively, which was remarkably higher than those of quercetin alone. Then we established hydrogen peroxide (H2O2)-induced oxidative injury model in human ARPE-19 cells to examine the effects of quercetin-PC. Quercetin-PC, stronger than quercetin, promoted cell proliferation, and the proliferation rate was increased to be 78.89% when treated with Quercetin-PC at 400μM. Moreover, quercetin-PC effectively prevented ARPE-19 cells from apoptosis, and the apoptotic rate was reduced to be 3.1% when treated with Quercetin-PC at 200μM. In addition, quercetin-PC at 200μM significantly increased the activities of SOD, CAT and GSH-PX, and reduced the levels of reactive oxygen species and MDA in H2O2-treated ARPE-19 cells, but quercetin at 200μM failed to do so. Molecular examinations revealed that quercetin-PC at 200μM significantly activated Nrf2 nuclear translocation and significantly enhanced the expression of target genes HO-1, NQO-1 and GCL by different folds at both mRNA and protein levels. Our current data collectively indicated that quercetin-PC had stronger protective effects against oxidative-induced damages in ARPE-19 cells, which was associated with activation of Nrf2 pathway and its target genes implicated in antioxidant defense.

  9. Simultaneous ingestion of high-methoxy pectin from apple can enhance absorption of quercetin in human subjects.

    PubMed

    Nishijima, Tomohiko; Takida, Yoshiki; Saito, Yasuo; Ikeda, Takayuki; Iwai, Kunihisa

    2015-05-28

    Chronic ingestion of apple pectin has been shown to increase the absorption of quercetin in rats. The present study was designed to elucidate whether the simultaneous ingestion of quercetin with apple pectin could enhance the absorption of quercetin in humans, and the effects of dose dependency and degree of pectin methylation on quercetin absorption were also investigated. Healthy volunteers (n 19) received 200 ml of 0.5 mg/ml of quercetin drinks with or without 10 mg/ml of pectin each in a randomised cross-over design study with over 1-week intervals; urine samples from all the subjects were collected within 24 h after ingestion of the test drinks, and urinary deconjugated quercetin and its metabolites were determined using HPLC. The sum of urinary quercetin and its metabolites excreted was increased by 2.5-fold by the simultaneous ingestion of pectin. The metabolism of methylated quercetin (isorhamnetin and tamarixetin) was not affected by pectin ingestion. In six volunteers, who received quercetin drinks containing 0, 3 and 10 mg/ml of pectin, the sum of urinary quercetin and its metabolites excreted also increased in a pectin dose-dependent manner. Furthermore, the simultaneous ingestion of quercetin with low-methoxy and high-methoxy pectin, respectively, increased the sum of urinary excretion of quercetin and its metabolites by 1.69-fold and significantly by 2.13-fold compared with the ingestion of quercetin without pectin. These results elucidated that apple pectin immediately enhanced quercetin absorption in human subjects, and that its enhancing effect was dependent on the dose and degree of pectin methylation. The results also suggested that the viscosity of pectin may play a role in the enhancement of quercetin absorption.

  10. Characterisation of metabolites of the putative cancer chemopreventive agent quercetin and their effect on cyclo-oxygenase activity

    PubMed Central

    Jones, D J L; Lamb, J H; Verschoyle, R D; Howells, L M; Butterworth, M; Lim, C K; Ferry, D; Farmer, P B; Gescher, A J

    2004-01-01

    Quercetin (3,5,7,3′,4′-pentahydroxyflavone) is a flavone with putative ability to prevent cancer and cardiovascular diseases. Its metabolism was evaluated in rats and human. Rats received quercetin via the intravenous (i.v.) route and metabolites were isolated from the plasma, urine and bile. Analysis was by high-performance liquid chromatography and confirmation of species identity was achieved by mass spectrometry. Quercetin and isorhamnetin, the 3′-O-methyl analogue, were found in both the plasma and urine. In addition, several polar peaks were characterised as sulphated and glucuronidated conjugates of quercetin and isorhamnetin. Extension of the metabolism studies to a cancer patient who had received quercetin as an i.v. bolus showed that (Quercetin removed) isorhamnetin and quercetin 3′-O-sulphate were major plasma metabolites. As a catechol, quercetin can potentially be converted to a quinone and subsequently conjugated with glutathione (GSH). Oxidation of quercetin with mushroom tyrosinase in the presence of GSH furnished GSH conjugates of quercetin, two mono- and one bis-substituted conjugates. However, these species were not found in biomatrices in rats treated with quercetin. As cyclo-oxygenase-2 (COX-2) expression is mechanistically linked to carcinogenesis, we examined whether quercetin and its metabolites can inhibit COX-2 in a human colorectal cancer cell line (HCA-7). Isorhamnetin and its 4′-isomer tamarixetin were potent inhibitors, reflected in a 90% decrease in prostaglandin E-2 (PGE-2) levels, a marker of COX-2 activity. Quercetin was less effective, with a 50% decline. Quercetin 3- and 7-O-sulphate had no effect on PGE-2. The results indicate that quercetin may exert its pharmacological effects, at least in part, via its metabolites. PMID:15292928

  11. Silk fibroin nanoparticles: Efficient vehicles for the natural antioxidant quercetin.

    PubMed

    Lozano-Pérez, Antonio Abel; Rivero, Héctor Correa; Pérez Hernández, María Del Carmen; Pagán, Ana; Montalbán, Mercedes G; Víllora, Gloria; Cénis, José Luis

    2017-02-25

    This article describes how silk fibroin nanoparticles (SFNs) are capable of adsorbing and releasing quercetin (Q) and how its integrity is highly preserved, as confirmed by antioxidant activity assays. Q loading onto SFNs was optimized in terms of the Q/SFN ratio (w/w), time of adsorption and solvent mixture. Quercetin-loaded silk fibroin nanoparticles (QSFNs) were characterized using the dynamic light scattering technique to measure the diameter (Z-Average) and Z-potential (ζ). Loaded particles were slightly bigger than the SFNs, while their ζ was less negative. The antioxidant activity against DPPH showed that the Q loaded in QSFNs not only retains the antioxidant activity but also has a synergistic scavenging activity due the intrinsic antioxidant activity of the SF. The drug loading content (DLC) and the encapsulation efficiency (EE) varied with the relation between Q and SFN in the loading solution. The sustained release of Q occurred throughout the experiment both in phosphate buffer saline (pH 7.4) and simulated intestinal fluid (pH 6.8). The results point to SFNs as promising candidates for Q loading, transport and gastrointestinal delivery with potential applications in nanomedicine, while retaining their nano-size and their antioxidant properties.

  12. Development of nanosuspension formulation for oral delivery of quercetin.

    PubMed

    Sun, Min; Gao, Yan; Pei, Yan; Guo, Chenyu; Li, Houli; Cao, Fengliang; Yu, Aihua; Zhai, Guangxi

    2010-08-01

    With the aim to enhance dissolution rate and oral bioavailability of quercetin, a poorly water-soluble drug, quercetin loaded nanosuspension (QT-NS) was fabricated by a tandem of nano-precipitation (NP) and high pressure homogenization (HPH) method. The formulation of nanosuspension was optimized by screening different stabilizers. Characterization of the original QT powder and QT-NS was carried out by transmission electron microscopy and scanning electron microscopy, X-ray diffraction (XRD) and dissolution tests. QT-NS presented a sphere-like shape under transmission electron microscopy with an average diameter of 393.5 nm and the zeta potential of -35.75 mV. XRD study suggested that QT was maintained in the state of crystalline during the fabrication process. The solubility of QT in nanosuspension was about 70-fold that of crude QT, and the dissolution of QT from QT-NS was increased as compared to that of the original QT powder. In plasma, QT-NS exhibited a significant reduction of clearance rate (2 +/- 0.1 mL/min vs. 15 +/- 4 mL/min) and increase of AUC(0-infinity), (53995 +/- 4126 microg/mL x min versus 3470 +/- 110.1 microg/mL x min) compared with the control suspension. Our results showed that the developed nanosuspension formulation had a great potential as a possible formulation of the poorly water-soluble QT to enhance the bioavailability.

  13. Anti-ageing and rejuvenating effects of quercetin.

    PubMed

    Chondrogianni, Niki; Kapeta, Suzanne; Chinou, Ioanna; Vassilatou, Katerina; Papassideri, Issidora; Gonos, Efstathios S

    2010-10-01

    Homeostasis is a key feature of the cellular lifespan. Its maintenance influences the rate of ageing and it is determined by several factors, including efficient proteolysis. The proteasome is the major cellular proteolytic machinery responsible for the degradation of both normal and damaged proteins. Alterations of proteasome function have been recorded in various biological phenomena including ageing and replicative senescence. Proteasome activities and function are decreased upon replicative senescence, whereas proteasome activation confers enhanced survival against oxidative stress, lifespan extension and maintenance of the young morphology longer in human primary fibroblasts. Several natural compounds possess anti-ageing/anti-oxidant properties. In this study, we have identified quercetin (QUER) and its derivative, namely quercetin caprylate (QU-CAP) as a proteasome activator with anti-oxidant properties that consequently influence cellular lifespan, survival and viability of HFL-1 primary human fibroblasts. Moreover, when these compounds are supplemented to already senescent fibroblasts, a rejuvenating effect is observed. Finally, we show that these compounds promote physiological alterations when applied to cells (i.e. whitening effect). In summary, these data demonstrate the existence of naturally occurring anti-ageing products that can be effectively used through topical application.

  14. Quercetin and Ascorbic Acid Suppress Fructose-Induced NLRP3 Inflammasome Activation by Blocking Intracellular Shuttling of TXNIP in Human Macrophage Cell Lines.

    PubMed

    Choe, Jung-Yoon; Kim, Seong-Kyu

    2017-03-22

    The aim of this study was to identify the role of thioredoxin-interacting protein (TXNIP) and its interaction with antioxidants in the activation of the fructose-induced NOD-like receptor protein 3 (NLRP3) inflammasome in human macrophages. The study was performed with U937 and THP-1 macrophage cell lines. Total reactive oxygen species (ROS) were measured by flow cytometry. Interleukin-1β (IL-1β), IL-18, NLRP3, TXNIP, and caspase-1 protein expression was detected using western blotting. Quantitative real-time polymerase chain reaction was used to detect IL-1β, IL-18, and caspase-1 gene expression. Intracellular shuttling of TXNIP was assessed by immunofluorescent staining with MitoTracker Red. Increased production of ROS and expression of IL-1β, IL-18, and caspase-1 genes and proteins were observed in U937 and THP-1 cells incubated with fructose and were effectively inhibited by quercetin and ascorbic acid. Intracellular shuttling of TXNIP from the nucleus into the mitochondria was detected under stimulation with fructose, which was also attenuated by antioxidants quercetin and ascorbic acid but not butylated hydroxyanisole. Treatment of macrophages with fructose promoted the association between TXNIP and NLRP3 in the cytosol, sequentially resulting in the activation of the NLRP3 inflammasome. This study revealed that intracellular TXNIP protein is a critical regulator of activation of the fructose-induced NLRP3 inflammasome, which can be effectively blocked by the antioxidants quercetin and ascorbic acid.

  15. Theoretical Study of the ESIPT Process for a New Natural Product Quercetin

    PubMed Central

    Yang, Yunfan; Zhao, Jinfeng; Li, Yongqing

    2016-01-01

    The investigation of excited-state intramolecular proton transfer (ESIPT) has been carried out via the density functional theory (DFT) and the time-dependent density functional theory (TDDFT) method for natural product quercetin in dichloromethane (DCM) solvent. For distinguishing different types of intramolecular interaction, the reduced density gradient (RDG) function also has been used. In this study, we have clearly clarified the viewpoint that two kinds of tautomeric forms (K1, K2)originated from ESIPT processconsist inthe first electronic excited state (S1). The phenomenon of hydrogen bonding interaction strengtheninghas been proved by comparing the changes of infrared (IR) vibrational spectra and bond parameters of the hydrogen bonding groups in the ground state with that in the first excited state. The frontier molecular orbitals (MOs)provided visual electron density redistribution have further verified the hydrogen bond strengthening mechanism. It should be noted that the ESIPT process of the K2 form is easier to occur than that of the K1 form via observing the potential energy profiles. Furthermore, the RDG isosurfaces has indicated that hydrogen bonding interaction of the K2 form is stronger than that of the K1 formin the S1 state, which is also the reason why the ESIPT process of the K2 form is easier to occur. PMID:27574105

  16. Theoretical Study of the ESIPT Process for a New Natural Product Quercetin

    NASA Astrophysics Data System (ADS)

    Yang, Yunfan; Zhao, Jinfeng; Li, Yongqing

    2016-08-01

    The investigation of excited-state intramolecular proton transfer (ESIPT) has been carried out via the density functional theory (DFT) and the time-dependent density functional theory (TDDFT) method for natural product quercetin in dichloromethane (DCM) solvent. For distinguishing different types of intramolecular interaction, the reduced density gradient (RDG) function also has been used. In this study, we have clearly clarified the viewpoint that two kinds of tautomeric forms (K1, K2)originated from ESIPT processconsist inthe first electronic excited state (S1). The phenomenon of hydrogen bonding interaction strengtheninghas been proved by comparing the changes of infrared (IR) vibrational spectra and bond parameters of the hydrogen bonding groups in the ground state with that in the first excited state. The frontier molecular orbitals (MOs)provided visual electron density redistribution have further verified the hydrogen bond strengthening mechanism. It should be noted that the ESIPT process of the K2 form is easier to occur than that of the K1 form via observing the potential energy profiles. Furthermore, the RDG isosurfaces has indicated that hydrogen bonding interaction of the K2 form is stronger than that of the K1 formin the S1 state, which is also the reason why the ESIPT process of the K2 form is easier to occur.

  17. Dietary quercetin exacerbates the development of estrogen-induced breast tumors in female ACI rats

    SciTech Connect

    Singh, Bhupendra; Mense, Sarah M.; Bhat, Nimee K.; Putty, Sandeep; Guthiel, William A.; Remotti, Fabrizio; Bhat, Hari K.

    2010-09-01

    Phytoestrogens are plant compounds that structurally mimic the endogenous estrogen 17{beta}-estradiol (E{sub 2}). Despite intense investigation, the net effect of phytoestrogen exposure on the breast remains unclear. The objective of the current study was to examine the effects of quercetin on E{sub 2}-induced breast cancer in vivo. Female ACI rats were given quercetin (2.5 g/kg food) for 8 months. Animals were monitored weekly for palpable tumors, and at the end of the experiment, rats were euthanized, breast tumor and different tissues excised so that they could be examined for histopathologic changes, estrogen metabolic activity and oxidant stress. Quercetin alone did not induce mammary tumors in female ACI rats. However, in rats implanted with E{sub 2} pellets, co-exposure to quercetin did not protect rats from E{sub 2}-induced breast tumor development with 100% of the animals developing breast tumors within 8 months of treatment. No changes in serum quercetin levels were observed in quercetin and quercetin + E{sub 2}-treated groups at the end of the experiment. Tumor latency was significantly decreased among rats from the quercetin + E{sub 2} group relative to those in the E{sub 2} group. Catechol-O-methyltransferase (COMT) activity was significantly downregulated in quercetin-exposed mammary tissue. Analysis of 8-isoprostane F{sub 2{alpha}} (8-iso-PGF{sub 2{alpha}}) levels as a marker of oxidant stress showed that quercetin did not decrease E{sub 2}-induced oxidant stress. These results indicate that quercetin (2.5 g/kg food) does not confer protection against breast cancer, does not inhibit E{sub 2}-induced oxidant stress and may exacerbate breast carcinogenesis in E{sub 2}-treated ACI rats. Inhibition of COMT activity by quercetin may expose breast cells chronically to E{sub 2} and catechol estrogens. This would permit longer exposure times to the carcinogenic metabolites of E{sub 2} and chronic exposure to oxidant stress as a result of metabolic redox

  18. Dietary Quercetin Exacerbates the Development of Estrogen-Induced Breast Tumors in Female ACI Rats

    PubMed Central

    Singh, Bhupendra; Mense, Sarah M.; Bhat, Nimee K.; Putty, Sandeep; Guthiel, William A.; Remotti, Fabrizio; Bhat, Hari K.

    2010-01-01

    Phytoestrogens are plant compounds that structurally mimic the endogenous estrogen 17β-estradiol (E2). Despite intense investigation, the net effect of phytoestrogen exposure on the breast remains unclear. The objective of the current study was to examine the effects of quercetin on E2-induced breast cancer in vivo. Female ACI rats were given quercetin (2.5 g/kg food) for 8 months. Animals were monitored weekly for palpable tumors, and at the end of the experiment, rats were euthanized, breast tumor and different tissues excised so that they could be examined for histopathologic changes, estrogen metabolic activity and oxidant stress. Quercetin alone did not induce mammary tumors in female ACI rats. However, in rats implanted with E2 pellets, co-exposure to quercetin did not protect rats from E2-induced breast tumor development with 100% of the animals developing breast tumors within 8 months of treatment. No changes in serum quercetin levels were observed in quercetin and quercetin + E2-treated groups at the end of the experiment. Tumor latency was significantly decreased among rats from the quercetin + E2 group relative to those in the E2 group. Catechol-O-methyltransferase (COMT) activity was significantly downregulated in quercetin exposed mammary tissue. Analysis of 8-isoprostane F2α (8-iso-PGF2α) levels as a marker of oxidant stress showed that quercetin did not decrease E2-induced oxidant stress. These results indicate that quercetin (2.5 g/kg food) does not confer protection against breast cancer, does not inhibit E2-induced oxidant stress and may exacerbate breast carcinogenesis in E2-treated ACI rats. Inhibition of COMT activity by quercetin may expose breast cells chronically to E2 and catechol estrogens. This would permit longer exposure times to the carcinogenic metabolites of E2 and chronic exposure to oxidant stress as a result of metabolic redox cycling to estrogen metabolites, and thus quercetin may exacerbate E2-induced breast tumors in female

  19. Rapid dimerization of quercetin through an oxidative mechanism in the presence of serum albumin decreases its ability to induce cytotoxicity in MDA-MB-231 cells

    SciTech Connect

    Pham, Anh; Bortolazzo, Anthony; White, J. Brandon

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer Quercetin cannot be detected intracellularly despite killing MDA-MB-231 cells. Black-Right-Pointing-Pointer Quercetin forms a heterodimer through oxidation in media with serum. Black-Right-Pointing-Pointer The quercetin heterodimer does not kill MDA-MB-231 cells. Black-Right-Pointing-Pointer Ascorbic acid stabilizes quercetin increasing cell death in quercetin treated cells. Black-Right-Pointing-Pointer Quercetin, and not a modified form, is responsible for apoptosis and cell death. -- Abstract: Quercetin is a member of the flavonoid family and has been previously shown to have a variety of anti-cancer activities. We and others have reported anti-proliferation, cell cycle arrest, and induction of apoptosis of cancer cells after treatment with quercetin. Quercetin has also been shown to undergo oxidation. However, it is unclear if quercetin or one of its oxidized forms is responsible for cell death. Here we report that quercetin rapidly oxidized in cell culture media to form a dimer. The quercetin dimer is identical to a dimer that is naturally produced by onions. The quercetin dimer and quercetin-3-O-glucopyranoside are unable to cross the cell membrane and do not kill MDA-MB-231 cells. Finally, supplementing the media with ascorbic acid increases quercetin's ability to induce cell death probably by reduction oxidative dimerization. Our results suggest that an unmodified quercetin is the compound that elicits cell death.

  20. Quercetin Significantly Inhibits the Metabolism of Caffeine, a Substrate of Cytochrome P450 1A2 Unrelated to CYP1A2*1C  (−2964G>A) and *1F (734C>A) Gene Polymorphisms

    PubMed Central

    Xiao, Jian; Huang, Wei-Hua; Peng, Jing-Bo; Tan, Zhi-Rong; Ou-Yang, Dong-Sheng; Hu, Dong-Li; Zhang, Wei; Chen, Yao

    2014-01-01

    Background. Quercetin is abundant in plants and human diets. Previous studies indicated that quercetin inhibited the activity of CYP1A2, and the combination of quercetin with the substrates of CYP1A2 might produce herb-drug interactions. This research aims to determine the effects of quercetin and the CYP1A2 gene polymorphisms, namely, CYP1A2*1C  (−2964G>A) and *1F (734C>A), on the metabolism of caffeine. Method. The experiment was designed into two treatment phases separated by a 2-week washout period. Six homozygous individuals for the CYP1A2*1C/*1F (GG/AA) genotype and 6 heterozygous individuals for the CYP1A2*1C/*1F (GA/CA) genotype were enrolled in the study. Quercetin capsules (500 mg) were given to each volunteer once daily for 13 consecutive days, and after that, each subject was coadministrated 100 mg caffeine capsules with 500 mg quercetin on the 14th day. Then a series of venous blood samples were collected for HPLC analysis. Correlation was determined between pharmacokinetics of caffeine and paraxanthine with caffeine metabolite ratio. Results. Quercetin significantly affected the pharmacokinetics of caffeine and its main metabolite paraxanthine, while no differences were found in the pharmacokinetics of caffeine and paraxanthine between GG/AA and GA/CA genotype groups. Conclusion. Quercetin significantly inhibits the caffeine metabolism, which is unrelated to CYP1A2*1C (−2964G>A) and *1F (734C>A) gene polymorphisms. PMID:25025048

  1. ABT-737 resistance in B-cells isolated from chronic lymphocytic leukemia patients and leukemia cell lines is overcome by the pleiotropic kinase inhibitor quercetin through Mcl-1 down-regulation.

    PubMed

    Russo, Maria; Spagnuolo, Carmela; Volpe, Silvestro; Tedesco, Idolo; Bilotto, Stefania; Russo, Gian Luigi

    2013-04-01

    Chronic lymphocytic leukemia (CLL) is the most frequent form of leukemia in adult population and despite numerous studies, it is considered an incurable disease. Since CLL is characterized by overexpression of pro-survival Bcl-2 family members, treatments with their antagonists, such as ABT-737, represent a promising new therapeutic strategy. ABT-737 is a BH3 mimetic agent which binds Bcl-2, Bcl-XL and Bcl-w with high affinity, while weakly interacts with Mcl-1 and Bfl-1. Previous studies demonstrated that quercetin, a flavonoid naturally present in food and beverages, was able to sensitize B-cells isolated from CLL patients to apoptosis when associated with death ligands or fludarabine, through a mechanism involving Mcl-1 down-regulation. Here, we report that the association between ABT-737 and quercetin synergistically induces apoptosis in B-cells and in five leukemic cell lines (Combination Index <1). Peripheral blood mononuclear cell from healthy donors were not affected by quercetin treatment. The molecular pathways triggered by quercetin have been investigated in HPB-ALL cells, characterized by the highest resistance to both ABT-737 and quercetin when applied as single molecules, but highly sensitivity to the co-treatment. In this cell line, quercetin down-regulated Mcl-1 through the inhibition of PI3K/Akt signaling pathway, leading to Mcl-1 instability. The same mechanism was confirmed in B-cells. These results may open new clinical perspectives based on a translational approach in CLL therapy. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. The effects of quercetin supplementation on cognitive functioning in a community sample: a randomized, placebo-controlled trial

    PubMed Central

    Canu, Will H.; Trout, Krystal L.; Nieman, David C.

    2012-01-01

    Background: The purpose of the present study was to examine the effects of quercetin supplementation on neurocognitive functioning. Methods: A large community sample (n = 941) completed a 12-week supplementation protocol, and participants were randomly assigned to receive 500 mg/day or 1000 mg/day quercetin, or placebo. Results: Results failed to indicate significant effects of quercetin on memory, psychomotor speed, reaction time, attention, or cognitive flexibility, despite large increases in plasma quercetin levels among the quercetin treatment groups. Discussion: Consistent with recent research, this study raises concerns regarding the generalizability of positive findings of in vitro and animal quercetin research, and provides evidence that quercetin may not have an ergogenic effect on neurocognitive functioning in humans. PMID:23983966

  3. Quercetin in Cancer Treatment, Alone or in Combination with Conventional Therapeutics?

    PubMed

    Brito, Ana Filipa; Ribeiro, Marina; Abrantes, Ana Margarida; Pires, Ana Salomé; Teixo, Ricardo Jorge; Tralhão, José Guilherme; Botelho, Maria Filomena

    2015-01-01

    Cancer is a problem of global importance, since the incidence is increasing worldwide and therapeutic options are generally limited. Thus, it becomes imperative to find new therapeutic targets as well as new molecules with therapeutic potential for tumors. Flavonoids are polyphenolic compounds that may be potential therapeutic agents. Several studies have shown that these compounds have a higher anticancer potential. Among the flavonoids in the human diet, quercetin is one of the most important. In the last decades, several anticancer properties of quercetin have been described, such as cell signaling, pro-apoptotic, anti-proliferative and anti-oxidant effects, growth suppression. In fact, it is now well known that quercetin has diverse biological effects, inhibiting multiple enzymes involved in cell proliferation, as well as, in signal transduction pathways. On the other hand, there are also studies reporting potential synergistic effects when combined quercetin with chemotherapeutic agents or radiotherapy. In fact, several studies which aim to explore the anticancer potential of these combined treatments have already been published, the majority with promising results. Actually it is well known that quercetin can act on the chemosensitization and radiosensitization but also as chemoprotective and radioprotective, protecting normal cells of the side effects that results from chemotherapy and radiotherapy, which obviously provides notable advantages in their use in anticancer treatment. Thus, all these data indicate that quercetin may have a key role in anticancer treatment. In this context, this review is focused on the relationship between flavonoids and cancer, with special emphasis on the role of quercetin.

  4. Quercetin induces HepG2 cell apoptosis by inhibiting fatty acid biosynthesis

    PubMed Central

    ZHAO, PENG; MAO, JUN-MIN; ZHANG, SHU-YUN; ZHOU, ZE-QUAN; TAN, YANG; ZHANG, YU

    2014-01-01

    Quercetin can inhibit the growth of cancer cells with the ability to act as a ‘chemopreventer’. Its cancer-preventive effect has been attributed to various mechanisms, including the induction of cell-cycle arrest and/or apoptosis, as well as its antioxidant functions. Quercetin can also reduce adipogenesis. Previous studies have shown that quercetin has potent inhibitory effects on animal fatty acid synthase (FASN). In the present study, activity of quercetin was evaluated in human liver cancer HepG2 cells. Intracellular FASN activity was calculated by measuring the absorption of NADPH via a spectrophotometer. MTT assay was used to test the cell viability, immunoblot analysis was performed to detect FASN expression levels and the apoptotic effect was detected by Hoechst 33258 staining. In the present study, it was found that quercetin could induce apoptosis in human liver cancer HepG2 cells with overexpression of FASN. This apoptosis was accompanied by the reduction of intracellular FASN activity and could be rescued by 25 or 50 μM exogenous palmitic acids, the final product of FASN-catalyzed synthesis. These results suggested that the apoptosis induced by quercetin was via the inhibition of FASN. These findings suggested that quercetin may be useful for preventing human liver cancer. PMID:25009654

  5. Effect of Quercetin on Hepatitis C Virus Life Cycle: From Viral to Host Targets.

    PubMed

    Rojas, Ángela; Del Campo, Jose A; Clement, Sophie; Lemasson, Matthieu; García-Valdecasas, Marta; Gil-Gómez, Antonio; Ranchal, Isidora; Bartosch, Birke; Bautista, Juan D; Rosenberg, Arielle R; Negro, Francesco; Romero-Gómez, Manuel

    2016-08-22

    Quercetin is a natural flavonoid, which has been shown to have anti hepatitis C virus (HCV) properties. However, the exact mechanisms whereby quercetin impacts the HCV life cycle are not fully understood. We assessed the effect of quercetin on different steps of the HCV life cycle in Huh-7.5 cells and primary human hepatocytes (PHH) infected with HCVcc. In both cell types, quercetin significantly decreased i) the viral genome replication; ii) the production of infectious HCV particles and iii) the specific infectivity of the newly produced viral particles (by 85% and 92%, Huh7.5 and PHH respectively). In addition, when applied directly on HCV particles, quercetin reduced their infectivity by 65%, suggesting that it affects the virion integrity. Interestingly, the HCV-induced up-regulation of diacylglycerol acyltransferase (DGAT) and the typical localization of the HCV core protein to the surface of lipid droplets, known to be mediated by DGAT, were both prevented by quercetin. In conclusion, quercetin appears to have direct and host-mediated antiviral effects against HCV.

  6. Magnetic nanoparticles for a new drug delivery system to control quercetin releasing for cancer chemotherapy

    NASA Astrophysics Data System (ADS)

    Barreto, A. C. H.; Santiago, V. R.; Mazzetto, S. E.; Denardin, J. C.; Lavín, R.; Mele, Giuseppe; Ribeiro, M. E. N. P.; Vieira, Icaro G. P.; Gonçalves, Tamara; Ricardo, N. M. P. S.; Fechine, P. B. A.

    2011-12-01

    Quercetin belongs to the chemical class of flavonoids and can be found in many common foods, such as apples, nuts, berries, etc. It has been demonstrated that quercetin has a wide array of biological effects that are considered beneficial to health treatment, mainly as anticancer. However, therapeutic applications of quercetin have been restricted to oral administration due to its sparing solubility in water and instability in physiological medium. A drug delivery methodology was proposed in this work to study a new quercetin release system in the form of magnetite-quercetin-copolymer (MQC). These materials were characterized through XRD, TEM, IR, and Thermal analysis. In addition, the magnetization curves and quercetin releasing experiments were performed. It was observed a nanoparticle average diameter of 11.5 and 32.5 nm at Fe3O4 and MQC, respectively. The presence of magnetic nanoparticles in this system offers the promise of targeting specific organs within the body. These results indicate the great potential for future applications of the MQC to be used as a new quercetin release system.

  7. Onion skin waste as a valorization resource for the by-products quercetin and biosugar.

    PubMed

    Choi, In Seong; Cho, Eun Jin; Moon, Jae-Hak; Bae, Hyeun-Jong

    2015-12-01

    Onion skin waste (OSW), which is produced from processed onions, is a major industrial waste. We evaluated the use of OSW for biosugar and quercetin production. The carbohydrate content of OSW was analyzed, and the optimal conversion conditions were evaluated by varying enzyme mixtures and loading volumes for biosugar production and quercetin extraction. The enzymatic conversion rate of OSW to biosugar was 98.5% at 0.72 mg of cellulase, 0.16 mg of pectinase, and 1.0mg of xylanase per gram of dry OSW. Quercetin extraction also increased by 1.61-fold after complete enzymatic hydrolysis. In addition, the newly developed nano-matrix (terpyridine-immobilized silica-coated magnetic nanoparticles-zinc (TSMNP-Zn matrix) was utilized to separate quercetin from OSW extracts. The nano-matrix facilitated easy separation and purification of quercetin. Using the TSMNP-Zn matrix the quercetin was approximately 90% absorbed. In addition, the recovery yield of quercetin was approximately 75% after treatment with ethylenediaminetetraacetic acid.

  8. Quercetin and alendronate multi-functionalized materials as tools to hinder oxidative stress damage.

    PubMed

    Forte, Lucia; Torricelli, Paola; Boanini, Elisa; Rubini, Katia; Fini, Milena; Bigi, Adriana

    2017-09-02

    In spite of its remarkable anti-oxidant, anti-inflammatory, anti-cancer properties and its possible inhibition activity towards bone resorption, quercetin therapeutic use is limited by its poor bioavailability. Herein we developed a new multifunctionalized system for the local administration of quercetin and alendronate, one of the most potent anti-osteoporotic drugs, with the aim to get a material with enhanced properties. To this purpose we loaded quercetin on hydroxyapatite functionalized with alendronate, as well as on hydroxyapatite. Characterization was performed by means of X-ray diffraction, FT-IR and Raman spectroscopies, thermogravimetric and spectrophotometric analyses. Loading of quercetin from hydro-alcoholic solution increased with time and reached a constant value of about 5 weight% on both substrates, without causing significant structural and morphological modifications. Quercetin functionalized materials exhibit relevant anti-oxidant properties, in agreement with their high radical scavenging activity, and a quercetin sustained release in phosphate buffer. In vitro osteoblast and osteoclast co-culture in a microenvironment altered by oxidative stress shows that both alendronate and quercetin significantly reduce osteoclast viability, whereas they are able to counteract the negative effect of oxidative stress on osteoblast viability and differentiation, suggesting that their relative amount in the functionalized materials can be utilized to tailor bone cells response. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2017. © 2017 Wiley Periodicals, Inc.

  9. Quercetin ameliorates Aβ toxicity in Drosophila AD model by modulating cell cycle-related protein expression

    PubMed Central

    Kong, Yan; Li, Ke; Fu, Tingting; Wan, Chao; Zhang, Dongdong; Song, Hang; Zhang, Yao; Liu, Na; Gan, Zhenji; Yuan, Liudi

    2016-01-01

    Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by β amyloid (Aβ) deposition and neurofibril tangles. It has been reported that a bioflavonoid, quercetin, could ameliorate AD phenotypes in C. elegans and mice. However, the mechanism underlying the ameliorative effect of quercetin is not fully understood yet. Drosophila models could recapitulate AD-like phenotypes, such as shortened lifespan, impaired locomotive ability as well as defects in learning and memory. So in this study, we investigated the effects of quercetin on AD in Drosophila model and explored the underlying mechanisms. We found quercetin could effectively intervene in AD pathogenesis in vivo. Mechanism study showed quercetin could restore the expression of genes perturbed by Aβ accumulation, such as those involved in cell cycle and DNA replication. Cyclin B, an important cell cycle protein, was chosen to test whether it participated in the AD ameliorative effects of quercetin. We found that cyclin B RNAi in the brain could alleviate AD phenotypes. Taken together, the current study suggested that the neuroprotective effects of quercetin were mediated at least partially by targeting cell cycle-related proteins. PMID:27626494

  10. Protective effects of quercetin against arsenic-induced testicular damage in rats.

    PubMed

    Baltaci, B B; Uygur, R; Caglar, V; Aktas, C; Aydin, M; Ozen, O A

    2016-12-01

    This study investigated the effect of quercetin on changes in testes due to arsenic exposure. Twenty-seven male rats were divided into three groups: control (10 ml kg(-1)  day(-1) saline), arsenic (10 mg kg(-1)  day(-1) sodium arsenite) and arsenic + quercetin (arsenic + 50 mg kg(-1)  day(-1) quercetin). The rats were sacrificed at the end of 15-day experiment. There was no difference between control group and arsenic group in body weight gain, testicular weight and serum total testosterone level. Quercetin treatment did not cause a significant difference in these parameters. In the arsenic group rats, we determined deterioration in the structure of seminiferous tubules, a decrease in the number of spermatogenic cells, an increase in the number of apoptotic cells, a decrease in the number of PCNA-positive cells, a decrease in SOD, CAT and GSH-Px activities, and an increase in the MDA level in testicular tissue. In all these changes, arsenic+quercetin group showed an improved compared to arsenic group. The amount of arsenic increased in the arsenic group was compared to the control group, and there was no difference between arsenic group and arsenic + quercetin group in the amount of arsenic. In conclusion, quercetin prevented arsenic-induced testicular damage with its anti-apoptotic and antioxidant effects.

  11. The critical role of quercetin in autophagy and apoptosis in HeLa cells.

    PubMed

    Wang, Yijun; Zhang, Wei; Lv, Qiongying; Zhang, Juan; Zhu, Dingjun

    2016-01-01

    In recent years, the effects of quercetin on autophagy and apoptosis of cancer cells have been widely reported, while effects on HeLa cells are still unclear. Here, HeLa cells were subjected to quercetin treatment, and then proliferation, apoptosis, and autophagy were evaluated using MTT, flow cytometry, and MDC staining, respectively. The LC3-I/II, Beclin 1, active caspase-3, and S6K1 phosphorylation were detected using Western blot assay. The ultrastructure of HeLa was observed via transmission electron microscope (TEM). Our findings showed that quercetin can dose-dependently inhibit the growth of HeLa cells. The MDC fluorescence was enhanced with increased concentration of quercetin and hit a plateau at 50 μmol/l. Western blot assay revealed that LC3-I/II ratio, Beclin 1, and active caspase-3 protein were enforced in a dose-dependent method. However, the phosphorylation of S6K1 gradually decreased, concomitant with an increase of autophagy. In addition, TEM revealed that the number of autophagic vacuoles was peaked at 50 μmol/l of quercetin. Besides, interference of autophagy with 3-MA led to proliferation inhibition and increased apoptosis in HeLa cells, accompanied by the decreased LC3-I/II conversion and the increased active caspase-3. In conclusion, quercetin can inhibit HeLa cell proliferation and induce protective autophagy at low concentrations; thus, 3-MA plus quercetin would suppress autophagy and effectively increased apoptosis.

  12. Quercetin ameliorates Aβ toxicity in Drosophila AD model by modulating cell cycle-related protein expression.

    PubMed

    Kong, Yan; Li, Ke; Fu, Tingting; Wan, Chao; Zhang, Dongdong; Song, Hang; Zhang, Yao; Liu, Na; Gan, Zhenji; Yuan, Liudi

    2016-10-18

    Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by β amyloid (Aβ) deposition and neurofibril tangles. It has been reported that a bioflavonoid, quercetin, could ameliorate AD phenotypes in C. elegans and mice. However, the mechanism underlying the ameliorative effect of quercetin is not fully understood yet. Drosophila models could recapitulate AD-like phenotypes, such as shortened lifespan, impaired locomotive ability as well as defects in learning and memory. So in this study, we investigated the effects of quercetin on AD in Drosophila model and explored the underlying mechanisms. We found quercetin could effectively intervene in AD pathogenesis in vivo. Mechanism study showed quercetin could restore the expression of genes perturbed by Aβ accumulation, such as those involved in cell cycle and DNA replication. Cyclin B, an important cell cycle protein, was chosen to test whether it participated in the AD ameliorative effects of quercetin. We found that cyclin B RNAi in the brain could alleviate AD phenotypes. Taken together, the current study suggested that the neuroprotective effects of quercetin were mediated at least partially by targeting cell cycle-related proteins.

  13. Plasma-Induced Degradation of Quercetin Associated with the Enhancement of Biological Activities.

    PubMed

    Kim, Tae Hoon; Lee, Jaemin; Kim, Hyun-Joo; Jo, Cheorun

    2017-08-16

    Nonthermal plasma is a promising technology to improve the safety and to extend the shelf-life of various minimally processed foods. However, research on plasma-induced systemic degradation related to changes in chemical structure and biological activity is still very limited. In this study, the enhancement of biological activity and the mechanism of degradation of the most common type of flavonol, quercetin, induced by a dielectric barrier discharge (DBD) plasma were investigated. Quercetin is dissolved in methanol and exposed to nonthermal DBD plasma for 5, 10, 20, and 30 min. The quercetin treated with the plasma for 20 min showed rapidly increased α-glucosidase inhibitory and radical scavenging activities compared to those of parent quercetin. The structures of the degradation products 1-3 from the quercetin treated with the plasma for 20 min were isolated and characterized by interpretation of their spectroscopic data. Among the generated products, (±)-alphitonin (1) exhibited significantly improved antidiabetic and antioxidant properties compared to those of the parent quercetin. The antidiabetic and antioxidant properties were measured by α-glucosidase inhibition and 1,1-diphenyl-2-picrylhydrazyl radical scavenging assays. These results suggested that structural changes in quercetin induced by DBD plasma might be attributable to improving the biological activity.

  14. Quercetin Influences Quorum Sensing in Food Borne Bacteria: In-Vitro and In-Silico Evidence

    PubMed Central

    Gopu, Venkadesaperumal; Meena, Chetan Kumar; Shetty, Prathapkumar Halady

    2015-01-01

    Quorum sensing (QS) plays a vital role in regulating the virulence factor of many food borne pathogens, which causes severe public health risk. Therefore, interrupting the QS signaling pathway may be an attractive strategy to combat microbial infections. In the current study QS inhibitory activity of quercetin and its anti-biofilm property was assessed against food-borne pathogens using a bio-sensor strain. In addition in-silico techniques like molecular docking and molecular dynamics simulation studies were applied to screen the quercetin’s potentiality as QS inhibitor. Quercetin (80μg/ml) showed the significant reduction in QS-dependent phenotypes like violacein production, biofilm formation, exopolysaccharide (EPS) production, motility and alginate production in a concentration-dependent manner. Synergistic activity of conventional antibiotics with quercetin enhanced the susceptibility of all tested pathogens. Furthermore, Molecular docking analysis revealed that quercetin binds more rigidly with LasR receptor protein than the signaling compound with docking score of -9.17Kcal/mol. Molecular dynamics simulation predicted that QS inhibitory activity of quercetin occurs through the conformational changes between the receptor and quercetin complex. Above findings suggest that quercetin can act as a competitive inhibitor for signaling compound towards LasR receptor pathway and can serve as a novel QS-based antibacterial/anti-biofilm drug to manage food-borne pathogens. PMID:26248208

  15. Temozolomide, quercetin and cell death in the MOGGCCM astrocytoma cell line.

    PubMed

    Jakubowicz-Gil, Joanna; Langner, Ewa; Wertel, Iwona; Piersiak, Tomasz; Rzeski, Wojciech

    2010-10-06

    The aim of the present study was to investigate the effect of Temozolomide (an alkylating chemotherapeutic agent) and quercetin (natural flavonoid) on cell death in the human astrocytoma cell line MOGGCCM (WHO grade III). Our results indicate that Temozolomide induces autophagy, while quercetin promotes severe necrosis in the cell line in a manner dependent on the drug concentration. We demonstrated for the first time that combinations of both drugs were much more effective in programmed cell death induction in glioma cells. At a low (5muM) drug concentration, quercetin potentiated a pro-autophagic effect of Temozolomide, while after treatment with a higher drug concentration (30muM), autophagy switched to apoptosis. Temozolomide attenuated the toxic effect of quercetin. Apoptosis was mediated by the mitochondrial pathway and the activation of caspase 3 and cytochrome C release, but no changes in caspase 8 expression was observed. It was accompanied by decreased mitochondrial membrane potential and inhibition of Hsp27 and Hsp72 expression. Autophagy was correlated with an increased level of LC3II. Temozolomide and quercetin also inhibited migratory phenotype of MOGGCCM cells and changed the nuclei morphology from a circular to an irregular shape. Our results indicate that quercetin acts in synergy with Temozolomide and when used in combination rather than in separate pharmacological application, both drugs are more effective in programmed cell death induction. Temozolomide administered with quercetin seems to be a potent and promising combination which might be useful in glioma therapy. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  16. Quercetin exhibits adjuvant activity by enhancing Th2 immune response in ovalbumin immunized mice.

    PubMed

    Singh, Divya; Tanwar, Himanshi; Jayashankar, Bindhya; Sharma, Jyoti; Murthy, Swetha; Chanda, Sudipta; Singh, Shashi Bala; Ganju, Lilly

    2017-04-02

    Quercetin, one of the most abundant of plant flavonoids, has been studied with a great deal of attention over the last several decades mainly for its properties in inflammation and allergy. In this study, we are reporting for the first time the in vivo immunostimulatory activity of quercetin in ovalbumin immunized Balb/c mice. Administration of quercetin (50mg/kg body weight) along with ovalbumin antigen showed increased ovalbumin specific serum IgG antibody titres in comparison to the control group (p<0.05). Quercetin administration not only showed predominance of Th2 immune response by increasing the IgG1 antibody titres, but also increased the infiltration of CD11c(+) dendritic cells in the mouse peritoneum and also increased LPS activated IL-1β and nitric oxide (NO) production by peritoneal macrophages. Expression of Tbx21, GATA-3 and Oct-2 proteins also enhanced in splenocytes of quercetin administered mice. Quercetin also did not cause any hemolysis in human RBCs. Overall, our findings strongly demonstrate the novel in vivo immunostimulatory and adjuvant potentials of quercetin.

  17. Chlorpyrifos induced hepatotoxic and hematologic changes in rats: the role of quercetin and catechin.

    PubMed

    Uzun, Fatma Gokce; Kalender, Yusuf

    2013-05-01

    Chlorpyrifos is an organophosphorus insecticide which is widely used throughout in the world and it caused toxic effects on nontarget organisms especially mammalian. In the present study, catechin, quercetin, chlorpyrifos, catechin+chlorpyrifos, quercetin+chlorpyrifos were given to male rats through gavage for 4weeks. Serum total protein, albumin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, lactate dehydrogenase, trigliceride, total cholesterol levels, hematological changes, superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase activities and malondialdehyde content in liver tissues and also histopathological changes of liver were investigated in the rats compared to control group. No significant differences in all investigated parameters were observed between control, catechin and quercetin groups. There were statistically significantly changes in liver function tests, some hematological parameters, antioxidant enzyme activities and malondialdehyde levels in chlorpyrifos treated group compared to control group. In catechin+chlorpyrifos treated group and quercetin+chlorpyrifos treated group we observed the protective effects of catechin and quercetin on examining parameters but not completely. While some histopathological changes detected in liver tissues in chlorpyrifos treated group, less histopathological changes were observed in catechin+chlorpyrifos and quercetin+chlorpyrifos treated groups at the end of the 4thweek. As a result, catechin and quercetin significantly reduce chlorpyrifos induced hepatotoxicity in rats.

  18. Alleviative effect of quercetin on rat testis against arsenic: a histological and biochemical study.

    PubMed

    Jahan, Sarwat; Iftikhar, Natasha; Ullah, Hizb; Rukh, Gul; Hussain, Ishtiaq

    2015-04-01

    The preventive effect of quercetin on arsenic stimulated reproductive ailments in male Sprague Dawely (SD) rats was investigated. Twenty rats were divided into four groups. The first group served as a control and was provided tap water. The second group of rats was treated with sodium arsenite at the dose of 50 ppm in drinking water. The third group served as a positive control and received an oral dose of quercetin (50 mg/kg). In the fourth group, quercetin (50 mg/kg) was co-administered orally with arsenic (50 ppm in drinking water). All the treatments were carried out for 49 days. Arsenic treatment resulted in adverse morphological and histopathological changes in testis of rats including reduced epithelial height and tubular diameter, and increased luminal diameter. In contrast, these adverse effects of arsenic were eliminated by co-administration of quercetin. Additionally arsenic treatment significantly increased testicular thiobarbituric acid reactive substance (TBARS) levels while catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and glutathione reductase (GSR) activities, and plasma and intra-testicular testosterone concentrations, were decreased significantly. Lipid peroxidation (LPO) was significantly suppressed and depleted antioxidant defense mechanism was restored by the quercetin co-treatment. Also quercetin treatment resulted in a marked increase in plasma and testicular testosterone concentrations. On the basis of these findings, it was concluded that quercetin may be used as a potential therapeutic drug against arsenic induced reproductive toxicity.

  19. Quercetin supplementation does not attenuate exercise performance and body composition in young female swimmers.

    PubMed

    Darvishi, Leila; Ghiasvand, Reza; Hariri, Mitra; Askari, Gholamreza; Rezai, Pejman; Aghaie, Mahmoud; Iraj, Bijan; Khosravi-Boroujeni, Hossein; Mashhadi, Nafiseh Shokri

    2013-04-01

    Quercetin is a health-enhancing antioxidant bioflavonoid (1-3). This flavonoid occurs in variety of natural fruits and vegetables such as apple, cranberry, onion, broccoli, and teas. Many studies have shown that quercetin has possible positive effects on exercise performance. The aim of this study is the evaluation of effects of quercetin supplementation on VO2max and exercise performance in female athletes. This study was done on 26 young female swimmers. Participants were assigned in to groups and supplemented orally for 8 weeks with either Quercetin (Solaray(®), USA, Inc) or placebo (dextrose). Before and after intervention, athletes performed a continuous graded exercise test (GXT) on an electronically braked cycle ergometer (Lode, The Netherlands) to determine VO2max and time to exhaustion (TTE). Participants in the quercetin group consumed higher energy and protein and lower carbohydrates and fats. There was no significant differences in VO2max, TTE, lactate, and body fat between pre- and post-supplementation neither in the placebo group nor in the quercetin group. It is concluded that quercetin supplementation (1000 g/day) for 8 weeks in female athletes didn't show any significant association with exercise performance.

  20. Quercetin and tin protoporphyrin attenuate hepatic ischemia reperfusion injury: role of HO-1.

    PubMed

    Atef, Yara; El-Fayoumi, Hassan M; Abdel-Mottaleb, Yousra; Mahmoud, Mona F

    2017-06-06

    Ischemia reperfusion (IR) injury occurs in many clinical situations such as organ transplantation and hepatectomies resulting in oxidative stress and immune activation. Heme oxygenase-1(HO-1) is the rate-limiting step in the heme-degradation pathway and has a critical cytoprotective role. Induction of HO-1 improves liver I/R injury. Quercetin, a plant pigment (flavonoid), is an antioxidant and HO-1 inducer. Tin protoporphyrin (SnPP) is a HO-1 inhibitor. This study was designed to investigate the protective effect of quercetin in hepatic I/R injury and the role of HO-1. Wister rats were randomly divided into four groups (sham, I/R, quercetin, and SnPP). Liver ischemia was induced for 45 min then reperfusion was allowed for 1 h. Quercetin and surprisingly SnPP ameliorate the deleterious effect of I/R by reducing the oxidative stress and hepatocyte degeneration. Both agents decreased the elevated inflammatory cytokines and improved the inhibition of the antiapoptotic marker, Bcl2. They induced HO-1 content and expression. Quercetin has better cytoprotective effect than SnPP. These findings suggest that quercetin has a hepatoprotective effect against I/R injury via HO-1 induction and unexpectedly, SnPP showed the similar effect. Quercetin has more prominent protective effect than SnPP because of its superior ability to induce HO-1.

  1. Effect of Quercetin on Hepatitis C Virus Life Cycle: From Viral to Host Targets

    PubMed Central

    Rojas, Ángela; Del Campo, Jose A.; Clement, Sophie; Lemasson, Matthieu; García-Valdecasas, Marta; Gil-Gómez, Antonio; Ranchal, Isidora; Bartosch, Birke; Bautista, Juan D.; Rosenberg, Arielle R.; Negro, Francesco; Romero-Gómez, Manuel

    2016-01-01

    Quercetin is a natural flavonoid, which has been shown to have anti hepatitis C virus (HCV) properties. However, the exact mechanisms whereby quercetin impacts the HCV life cycle are not fully understood. We assessed the effect of quercetin on different steps of the HCV life cycle in Huh-7.5 cells and primary human hepatocytes (PHH) infected with HCVcc. In both cell types, quercetin significantly decreased i) the viral genome replication; ii) the production of infectious HCV particles and iii) the specific infectivity of the newly produced viral particles (by 85% and 92%, Huh7.5 and PHH respectively). In addition, when applied directly on HCV particles, quercetin reduced their infectivity by 65%, suggesting that it affects the virion integrity. Interestingly, the HCV-induced up-regulation of diacylglycerol acyltransferase (DGAT) and the typical localization of the HCV core protein to the surface of lipid droplets, known to be mediated by DGAT, were both prevented by quercetin. In conclusion, quercetin appears to have direct and host-mediated antiviral effects against HCV. PMID:27546480

  2. Quercetin-3-O-glucuronide induces ABCA1 expression by LXRα activation in murine macrophages

    SciTech Connect

    Ohara, Kazuaki; Wakabayashi, Hideyuki; Taniguchi, Yoshimasa; Shindo, Kazutoshi; Yajima, Hiroaki; Yoshida, Aruto

    2013-11-29

    Highlights: •The major circulating quercetin metabolite (Q3GA) activated LXRα. •Q3GA induced ABCA1 via LXRα activation in macrophages. •Nelumbo nucifera leaf extracts contained quercetin glycosides. •N. nucifera leaf extract feeding elevated HDLC in mice. -- Abstract: Reverse cholesterol transport (RCT) removes excess cholesterol from macrophages to prevent atherosclerosis. ATP-binding cassette, subfamily A, member 1 (ABCA1) is a crucial cholesterol transporter involved in RCT to produce high density lipoprotein-cholesterol (HDLC), and is transcriptionally regulated by liver X receptor alpha (LXRα), a nuclear receptor. Quercetin is a widely distributed flavonoid in edible plants which prevented atherosclerosis in an animal model. We found that quercetin-3-O-glucuronide (Q3GA), a major quercetin metabolite after absorption from the digestive tract, enhanced ABCA1 expression, in vitro, via LXRα in macrophages. In addition, leaf extracts of a traditional Asian edible plant, Nelumbo nucifera (NNE), which contained abundant amounts of quercetin glycosides, significantly elevated plasma HDLC in mice. We are the first to present experimental evidence that Q3GA induced ABCA1 in macrophages, and to provide an alternative explanation to previous studies on arteriosclerosis prevention by quercetin.

  3. Protective Effects of Quercetin against Dimethoate-Induced Cytotoxicity and Genotoxicity in Allium sativum Test.

    PubMed

    Ahmad, Waseem; Shaikh, Sibhghatulla; Nazam, Nazia; Lone, Mohammad Iqbal

    2014-01-01

    The present investigation was directed to study the possible protective activity of quercetin-a natural antioxidant against dimethoate-induced cyto- and genotoxicity in meristematic cells of Allium sativum. So far there is no report on the biological properties of quercetin in plant test systems. Chromosome breaks, multipolar anaphase, stick chromosome, and mitotic activity were undertaken in the current study as markers of cyto- and genotoxicity. Untreated control, quercetin controls (@ 5, 10 and 20 μg/mL for 3 h), and dimethoate exposed groups (@ 100 and 200 μg/mL for 3 h) were maintained. For protection against cytogenotoxicity, the root tip cells treated with dimethoate at 100 and 200 μg/mL for 3 h and quercetin treatment at 5, 10, and 20 μg/mL for 16 h, prior to dimethoate treatment, were undertaken. Quercetin was found to be neither cytotoxic nor genotoxic in Allium sativum control at these doses. A significant increase (P < 0.05) in chromosomal aberrations was noted in dimethoate treated Allium. Pretreatment of Allium sativum with quercetin significantly (P < 0.05) reduced dimethoate-induced genotoxicity and cytotoxicity in meristematic cells, and these effects were dose dependent. In conclusion, quercetin has a protective role in the abatement of dimethoate-induced cyto- and genotoxicity in the meristematic cells of Allium sativum that resides, at least in part, on its antioxidant effects.

  4. Quercetin induces HepG2 cell apoptosis by inhibiting fatty acid biosynthesis.

    PubMed

    Zhao, Peng; Mao, Jun-Min; Zhang, Shu-Yun; Zhou, Ze-Quan; Tan, Yang; Zhang, Yu

    2014-08-01

    Quercetin can inhibit the growth of cancer cells with the ability to act as a 'chemopreventer'. Its cancer-preventive effect has been attributed to various mechanisms, including the induction of cell-cycle arrest and/or apoptosis, as well as its antioxidant functions. Quercetin can also reduce adipogenesis. Previous studies have shown that quercetin has potent inhibitory effects on animal fatty acid synthase (FASN). In the present study, activity of quercetin was evaluated in human liver cancer HepG2 cells. Intracellular FASN activity was calculated by measuring the absorption of NADPH via a spectrophotometer. MTT assay was used to test the cell viability, immunoblot analysis was performed to detect FASN expression levels and the apoptotic effect was detected by Hoechst 33258 staining. In the present study, it was found that quercetin could induce apoptosis in human liver cancer HepG2 cells with overexpression of FASN. This apoptosis was accompanied by the reduction of intracellular FASN activity and could be rescued by 25 or 50 μM exogenous palmitic acids, the final product of FASN-catalyzed synthesis. These results suggested that the apoptosis induced by quercetin was via the inhibition of FASN. These findings suggested that quercetin may be useful for preventing human liver cancer.

  5. Quercetin supplementation does not enhance cerebellar mitochondrial biogenesis and oxidative status in exercised rats.

    PubMed

    Casuso, Rafael A; Martínez-Amat, Antonio; Hita-Contreras, Fidel; Camiletti-Moirón, Daniel; Aranda, Pilar; Martínez-López, Emilio

    2015-07-01

    The present study tested the hypothesis that quercetin may inhibit the mitochondrial and antioxidant adaptations induced by exercise in cerebellar tissue. Thirty-five 6-week-old Wistar rats were randomly allocated into the following groups: quercetin, exercised (Q-Ex; n = 9); quercetin, sedentary (Q-Sed; n = 9); no quercetin, exercised (NQ-Ex; n = 9); and no quercetin, sedentary (NQ-Sed; n = 8). After 6 weeks of quercetin supplementation and/or exercise training, cerebellums were collected. Protein carbonyl content (PCC), sirtuin 1, peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), messenger RNA levels, citrate synthase (CS), and mitochondrial DNA were measured. When Q-Sed was compared with NQ-Sed, PCC (P < .005) showed decreased levels, whereas PGC-1α, sirtuin 1 (both, P < .01), mitochondrial DNA (P < .001), and CS (P < .01) increased. However, when Q-Ex was compared with Q-Sed, PCC showed increased levels (P < .001), whereas CS decreased (P < .01). Furthermore, the NQ-Ex group experienced an increase in PGC-1α messenger RNA levels in comparison with NQ-Sed (P > .01). This effect, however, did not appear in Q-Ex (P < .05). Therefore, we must hypothesize that either the dose (25 mg/kg) or the length of the quercetin supplementation period that was used in the present study (or perhaps both) may impair exercise-induced adaptations in cerebellar tissue. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Disruption of quercetin metabolism by fungicide affects energy production in honey bees (Apis mellifera).

    PubMed

    Mao, Wenfu; Schuler, Mary A; Berenbaum, May R

    2017-03-07

    Cytochrome P450 monooxygenases (P450) in the honey bee, Apis mellifera, detoxify phytochemicals in honey and pollen. The flavonol quercetin is found ubiquitously and abundantly in pollen and frequently at lower concentrations in honey. Worker jelly consumed during the first 3 d of larval development typically contains flavonols at very low levels, however. RNA-Seq analysis of gene expression in neonates reared for three days on diets with and without quercetin revealed that, in addition to up-regulating multiple detoxifying P450 genes, quercetin is a negative transcriptional regulator of mitochondrion-related nuclear genes and genes encoding subunits of complexes I, III, IV, and V in the oxidative phosphorylation pathway. Thus, a consequence of inefficient metabolism of this phytochemical may be compromised energy production. Several P450s metabolize quercetin in adult workers. Docking in silico of 121 pesticide contaminants of American hives into the active pocket of CYP9Q1, a broadly substrate-specific P450 with high quercetin-metabolizing activity, identified six triazole fungicides, all fungal P450 inhibitors, that dock in the catalytic site. In adults fed combinations of quercetin and the triazole myclobutanil, the expression of five of six mitochondrion-related nuclear genes was down-regulated. Midgut metabolism assays verified that adult bees consuming quercetin with myclobutanil metabolized less quercetin and produced less thoracic ATP, the energy source for flight muscles. Although fungicides lack acute toxicity, they may influence bee health by interfering with quercetin detoxification, thereby compromising mitochondrial regeneration and ATP production. Thus, agricultural use of triazole fungicides may put bees at risk of being unable to extract sufficient energy from their natural food.

  7. Long term dietary quercetin enrichment as a cardioprotective countermeasure in mdx mice.

    PubMed

    Ballmann, Christopher; Denney, Thomas; Beyers, Ronald J; Quindry, Tiffany; Romero, Matthew; Selsby, Joshua T; Quindry, John C

    2017-02-13

    Duchenne Muscular Dystrophy (DMD) causes declines in cardiac health resulting in premature mortality. As a potential countermeasure, quercetin is a polyphenol possessing inherent anti-inflammatory and antioxidant effects that activate proliferator-activated γ coactivator 1α (PGC-1α) increasing mitochondrial biogenesis protein abundance. We investigated the extent to which lifelong 0.2% dietary quercetin enrichment attenuates dystrophic cardiopathology in mdx mice. Dystrophic animals were fed quercetin or control diet for 12 months while control C57 mice were fed a control diet. Cardiac function was assessed via 7T MRI at 2, 10, and 14 months. At 14 months hearts were collected for histology and western blotting. Results indicate mdx strain dependent declines in cardiac performance at 14 months and that dietary quercetin enrichment did not attenuate functional losses. In contrast, histological analyses provide evidence that quercetin feeding was associated with decreased fibronectin, and indirect damage indices (Hematoxylin & Eosin) as compared to mdx. Dietary quercetin enrichment increased cardiac protein abundance of PGC-1α, cytochrome-c, ETC complexes I-V, citrate synthase, SOD2, and GPX versus untreated mdx. Protein abundance of inflammatory markers NFκB, P-NFκB, and P-IKBα were decreased by quercetin compared to untreated mdx, while preserving IKBα compared to mdx. Furthermore, quercetin decreased TGF-β1, COX2, and F4/80 versus untreated mdx mice. Data suggest that long term quercetin enrichment does not impact physiologic parameters of cardiac function but improves indices of mitochondrial biogenesis and antioxidant enzymes, facilitated DGC assembly, and decreased inflammation in dystrophic hearts. This article is protected by copyright. All rights reserved.

  8. Metabonomic analysis of quercetin against the toxicity of acrylamide in rat urine.

    PubMed

    Bao, Wei; Cao, Can; Li, Siqi; Bo, Lu; Zhang, Meiyan; Zhao, Xiujuan; Liu, Ying; Sun, Changhao

    2017-03-22

    This research aims to determine whether quercetin has protective effects against the toxicity of acrylamide (AA) using metabonomic technology. Randomly, the rats were assigned into a control group, AA treatment group, quercetin treatment group and quercetin plus AA treatment group. Quercetin and AA were administered to rats daily via gavage and drinking water for 16 weeks, respectively. To detect the metabonomic profiles of urine, ultra-performance liquid chromatography/mass spectrometry was used. A total of 15 metabolites, including biomarkers of AA exposure (GAMA, AAMA, and iso-AAMA) and quercetin exposure (quercetin and isorhamnetin), were identified. In comparison with the control group, the intensities of GAMA, AAMA, iso-AAMA, 1-salicylate glucuronide, vinylacetylglycine, PE(20:1(11Z)/14:0), 7-ketodeoxycholic acid, cysteic acid, p-cresol sulfate, and l-cysteine in the AA-treated group were statistically significantly increased (p < 0.01), and the intensities of 2-indolecarboxylic acid, 3-acetamidobutanal, and kynurenic acid in the AA-treated group were statistically significantly decreased (p < 0.01). The above-mentioned metabolites were significantly ameliorated in the quercetin (50 mg per kg bw) plus AA-treated group compared with the AA-treated group (p < 0.01 or p < 0.05). However, the intensities of these metabolites in the quercetin (50 mg per kg bw) plus AA-treated groups were still significantly different from those of the control group (p < 0.01 or p < 0.05). The above results suggest that quercetin has a partial protective effect on AA-induced toxicity. The protective effects include regulation of fatty acid metabolism and amino acid metabolism and enhancing the antioxidant defense system.

  9. The flavonoid quercetin in disease prevention and therapy: facts and fancies.

    PubMed

    Russo, Maria; Spagnuolo, Carmela; Tedesco, Idolo; Bilotto, Stefania; Russo, Gian Luigi

    2012-01-01

    Biochemical and genetic studies on cellular and animal models on the mechanism(s) of action of phytochemicals provide a functional explanation of how and why a diet rich in fruits and vegetables is considered healthy. It is not unusual to find molecules that protect against diseases, which greatly differ from a physiopathological point of view, such as cancer and cardiovascular disorders. Quercetin falls into this category and possesses a broad range of biological properties. Uptake, metabolism and circulating concentrations of quercetin and its metabolites suggest that a regular diet provides amounts of quercetin (<1 μM) not compatible with its chemopreventive and/or cardioprotective effects. However, it appears relatively easy to increase total quercetin concentrations in plasma (>10 μM) by supplementation with quercetin-enriched foods or supplements. Multiple lines of experimental evidence suggest a positive association between quercetin intake and improved outcomes of inflammatory cardiovascular risk. The ameliorating effect of quercetin administration can be extended to other chronic inflammatory disorders but only if supplementation occurs in patients. Quercetin can be considered the prototype of a naturally-occurring chemopreventive agent because of its key roles in triggering the "hallmarks of cancer". However, several critical points must be taken into account when considering the potential therapeutic use of this molecule: (1) pharmacological versus nutraceutical doses applied, (2) specificity of its mechanism of action compared to other phytochemicals, and (3) identification of "direct" cellular targets. The design of specific clinical trials is extremely warranted to depict possible applications of quercetin in adjuvant cancer therapy. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Quercetin Decreases Insulin Resistance in a Polycystic Ovary Syndrome Rat Model by Improving Inflammatory Microenvironment.

    PubMed

    Wang, Zhenzhi; Zhai, Dongxia; Zhang, Danying; Bai, Lingling; Yao, Ruipin; Yu, Jin; Cheng, Wen; Yu, Chaoqin

    2017-05-01

    Insulin resistance (IR) is a clinical feature of polycystic ovary syndrome (PCOS). Quercetin, derived from Chinese medicinal herbs such as hawthorn, has been proven practical in the management of IR in diabetes. However, whether quercetin could decrease IR in PCOS is unknown. This study aims to observe the therapeutic effect of quercetin on IR in a PCOS rat model and explore the underlying mechanism. An IR PCOS rat model was established by subcutaneous injection with dehydroepiandrosterone. The body weight, estrous cycle, and ovary morphology of the quercetin-treated rats were observed. Serum inflammatory cytokines were analyzed using enzyme-linked immunosorbent assay. In ovarian tissues, the expression of key genes involved in the inflammatory signaling pathway was detected through Western blot, real-time polymerase chain reaction, or immunohistochemistry. The nuclear translocation of nuclear factor κB (NF-κB) was also observed by immunofluorescence. The estrous cycle recovery rate of the insulin-resistant PCOS model after quercetin treatment was 58.33%. Quercetin significantly reduced the levels of blood insulin, interleukin 1β, IL-6, and tumor necrosis factor α. Quercetin also significantly decreased the granulosa cell nuclear translocation of NF-κB in the insulin-resistant PCOS rat model. The treatment inhibited the expression of inflammation-related genes, including the nicotinamide adenine dinucleotide phosphate oxidase subunit p22phox, oxidized low-density lipoprotein, and Toll-like receptor 4, in ovarian tissue. Quercetin improved IR and demonstrated a favorable therapeutic effect on the PCOS rats. The underlying mechanism of quercetin potentially involves the inhibition of the Toll-like receptor/NF-κB signaling pathway and the improvement in the inflammatory microenvironment of the ovarian tissue of the PCOS rat model.

  11. Quercetin induces apoptosis by inhibiting MAPKs and TRPM7 channels in AGS cells.

    PubMed

    Kim, Min Chul; Lee, Hee Jung; Lim, Bora; Ha, Ki-Tae; Kim, Sung Young; So, Insuk; Kim, Byung Joo

    2014-06-01

    The worldwide incidence and mortality rate of gastric cancer remain high, and thus, novel treatment concepts are required. Quercetin, a bioflavonoid, has been proposed to have anti-cancer properties. The aim of this study was to determine the nature of the apoptotic mechanisms responsible for the effects of quercetin on AGS cells (a commonly used human gastric adenocarcinoma cell line). AGS cell viability was assessed by MTT assay and flow cytometric analysis, mitochondrial membrane depolarization was assessed, and caspase-3 was used to determine the involvement of apoptosis. Whole-cell configuration patch-clamp experiments were used to regulate the transient receptor potential melastatin (TRPM)7 channels. To investigate the signaling pathway of quercetin-induced apoptosis in the AGS cells, western blot analysis and MTT assay were performed. Quercetin was found to induce the apoptosis of these cells, and this apoptosis was inhibited by SB203580 (a p38 kinase inhibitor), SP600125 (a JNK inhibitor) and PD98059 (an ERK inhibitor). In addition, quercetin inhibited TRPM7 currents in the AGS cells and in human embryo kidney (HEK)293 cells which overexpress TRPM7 channels. Furthermore, treatment with quercetin increased the apoptosis of HEK293 cells, which overexpress TRPM7, indicating that the upregulation of TRPM7 channels underlies quercetin-induced cell death. These results suggest that quercetin plays an important pathophysiological role in AGS cells through mitogen‑activated protein kinase (MAPK) signaling pathways and TRPM7 channels, and that quercetin has potential as a pharmacological agent for the treatment of gastric cancer.

  12. [Protective effect of quercetin against immunological liver injury through activating Nrf2/ARE signaling pathway].

    PubMed

    Wei, Caibing; Zhou, Liandi; Zhang, Yuzhen; Zhang, Jiawei; Zhang, Qihui; Tao, Kun

    2017-03-01

    Objective To observe the protective effect of quercetin against immunological liver injury induced by triptolide, and investigate the involvement of Nrf2/ARE signaling pathway in the protection. Methods Fifty C57BL/6J mice were randomly divided into five groups: control group, model group, (20, 50, 80) mg/kg quercetin pre-treatment groups. Each group included 10 mice. The mice were treated with different doses of quercetin once daily for consecutive 10 days. At the end of the experiment, triptolide (500 μg/kg) was given intragastrically to induce immunological liver injury in all groups except for the control group. Twenty-two hours later, the levels of serum ALT , AST were detected. The contents of GSH, SOD and MDA in liver tissue homogenates were measured through commercial kits. HE staining was performed to observe pathologic changes of the liver. The mRNA expressions of heme oxygenase-1 (HO-1), NQO1, glutamate-cysteine ligase catalytic subunit (GCLC) was tested by quantitative real-time PCR, and the protein expression of Nrf2 was detected by Western blotting. Results Compared with the model group, the serum activities of ALT and AST as well as MDA content remarkably decreased by the administration of quercetin (80 mg/kg), while GSH, SOD contents were elevated in liver tissues; pathologic changes of the liver was ameliorated evidently by quercetin; Nrf2 protein expression in the nucleus as well as mRNA expressions of HO-1, NQO1, GCLC increased. Moreover, the protective effect of 50 mg/kg quercetin was not as good as that of 80 mg/kg quercetin, and 20 mg/kg quercetin did little against the immunological liver injury. Conclusion High-dose quercetin can inhibit immunological liver injury induced by triptolide, and the mechanism may be associated with the activation of Nrf2/ARE signaling pathway.

  13. Screening of flavonoid "quercetin" from the rhizome of Smilax china Linn. for anti-psoriatic activity.

    PubMed

    Vijayalakshmi, A; Ravichandiran, V; Malarkodi, Velraj; Nirmala, S; Jayakumari, S

    2012-04-01

    To assess anti-psoriatic activity of the methanol extract and the isolated flavonoid quercetin from the rhizome of Smilax china (S. china) Linn. Mouse tail test was used for the evaluation of anti-psoriatic activity. Methanol extract (100 and 200 mg/kg b.w.) and isolated flavonoid quercetin (25 and 50 mg/kg b.w.) were tested in Swiss albino mice. Parameters studied in the mouse tail test were changes in epidermal thickness and percentage orthokeratotic values. The anti-inflammatory role of the methanol extract and isolated flavonoid quercetin was evaluated using carrageenan-induced pleurisy in rats. In vitro antiproliferant assay on HaCaT cell lines was also carried out. The isolated flavonoid quercetin from the rhizome of S. china produced significant orthokeratosis (P<0.01) in the mouse tail test. In epidermal thickness, a significant reduction with respect to control was observed in groups treated with retinoic acid and isolated flavonoid quercetin. The methanol extract (200 mg/kg) and isolated flavonoid quercetin (50 mg/kg) showed anti-inflammatory effect in terms of significant inhibition (P<0.001) in leukocyte migration. Maximum antiproliferant activity was shown by isolated flavonoid quercetin (IC50, 62.42±10.20 µg/mL). From the above data, the flavonoid quercetin shows significant orthokeratosis, anti-inflammatory and maximum antiproliferant activities. To our knowledge, this is the first report on the anti-psoriatic effect of the flavonoid quercetin which is promising for further investigations to prove its anti-psoriatic activity.

  14. Quercetin Stimulates Insulin Secretion and Reduces the Viability of Rat INS-1 Beta-Cells.

    PubMed

    Kittl, Michael; Beyreis, Marlena; Tumurkhuu, Munkhtuya; Fürst, Johannes; Helm, Katharina; Pitschmann, Anna; Gaisberger, Martin; Glasl, Sabine; Ritter, Markus; Jakab, Martin

    2016-01-01

    Previously we described insulinotropic effects of Leonurus sibiricus L. plant extracts used for diabetes mellitus treatment in Traditional Mongolian Medicine. The flavonoid quercetin and its glycoside rutin, which exert anti-diabetic properties in vivo by interfering with insulin signaling in peripheral target tissues, are constituents of these extracts. This study was performed to better understand short- and long-term effects of quercetin and rutin on beta-cells. Cell viability, apoptosis, phospho-protein abundance and insulin release were determined using resazurin, annexin-V binding assays, Western blot and ELISA, respectively. Membrane potentials (Vmem), whole-cell Ca2+ (ICa)- and ATP-sensitive K+ (IKATP) currents were measured by patch clamp. Intracellular Ca2+ (Cai) levels were measured by time-lapse imaging using the ratiometric Ca2+ indicator Fura-2. Rutin, quercetin and the phosphoinositide-3-kinase (PI3K) inhibitor LY294002 caused a dose-dependent reduction in cell viability with IC50 values of ∼75 µM, ∼25 µM and ∼3.5 µM, respectively. Quercetin (50 µM) significantly increased the percentage of Annexin-V+ cells within 48 hrs. The mean cell volume (MCV) of quercetin-treated cells was significantly lower. Within 2 hrs, quercetin significantly decreased basal- and insulin-stimulated Akt(T308) phosphorylation and increased Erk1/2 phosphorylation, without affecting P-Akt(S473) abundance. Basal- and glucose-stimulated insulin release were significantly stimulated by quercetin. Quercetin significantly depolarized Vmem by ∼25 mV which was prevented by the KATP-channel opener diazoxide, but not by the L-type ICa inhibitor nifedipine. Quercetin significantly stimulated ICa and caused a 50% inhibition of IKATP. The effects on Vmem, ICa and IKATP rapidly reached peak values and then gradually diminished to control values within ∼1 minute. With a similar time-response quercetin induced an elevation in Cai which was completely abolished in the absence of

  15. Flavonols enhanced production of anti-inflammatory substance(s) by Bifidobacterium adolescentis: prebiotic actions of galangin, quercetin, and fisetin.

    PubMed

    Kawabata, Kyuichi; Sugiyama, Yuta; Sakano, Taiken; Ohigashi, Hajime

    2013-01-01

    The gut microbiota is capable of the bioconversion of flavonoids whereas influences of probiotic anaerobes on the bioactivities of flavonoids and vice versa are still unclear. Here, we investigated functional interactions with respect to the anti-inflammatory activity between flavonols and probiotic bacteria. Ten enteric (6 probiotic and 4 indigenous) bacteria were incubated with flavonols (galangin, kaempferol, quercetin, myricetin, and fisetin) under anaerobic conditions, and the supernatants were assessed for their effects on nitric oxide (NO) production in lipopolysaccaride-stimulated RAW264 cells. Although the conditioned medium from the flavonol mono-culture and almost all of the tested co-cultures failed to inhibit NO production, the medium from the Bifidobacterium adolescentis/flavonols (galangin, quercetin, and fisetin) co-culture highly suppressed NO production. This activity increased during the 1-6 H incubation in a time-dependent manner and was not observed in the co-culture using heat-inactivated B. adolescentis. Interestingly, when the B. adolescentis cell number was increased, the supernatant from the mono-culture of the bacteria showed NO suppression, suggesting that B. adolescentis may produce NO suppressant(s), and flavonols may have a promoting effect. These findings indicate that flavonols have a prebiotic-like effect on the anti-inflammatory activity of B. adolescentis.

  16. Quercetin-loaded PLGA nanoparticles: a highly effective antibacterial agent in vitro and anti-infection application in vivo

    NASA Astrophysics Data System (ADS)

    Sun, Dongdong; Li, Nuan; Zhang, Weiwei; Yang, Endong; Mou, Zhipeng; Zhao, Zhiwei; Liu, Haiping; Wang, Weiyun

    2016-01-01

    Nanotechnology-based approaches have tremendous potential for enhancing efficacy against infectious diseases. PLGA-based nanoparticles as drug delivery carrier have shown promising potential, owing to their sizes and related unique properties. This article aims to develop nanosized poly ( d, l-lactide-co-glycolide) PLGA nanoparticle formulation loaded with quercetin (QT). QT is an antioxidant and antibacterial compound isolated from Chinese traditional medicine with low skin permeability and extreme water insolubility. The quercetin-loaded PLGA nanoparticles (PQTs) were synthesized by emulsion-solvent evaporation method and stabilized by coating with poly (vinyl alcohol). The characteristics of PQTs were analyzed by Fourier transform infrared spectroscopy, Ultraviolet-Visible spectroscopy, scanning electron microscope, transmission electron microscopy, and atomic force microscopy, respectively. The PQTs showed a spherical shape with an average size of 100-150 nm. We compared the antibacterial effects of PQTs against Escherichia coli ( E. coli) and Micrococcus tetragenus ( M. tetragenus).The PQTs produced stronger antibacterial activity to E. coli than that to M. tetragenus through disrupting bacterial cell wall integrity. The antibacterial ratio was increased with the increasing dosages and incubation time. Next, we tested the in vivo antibacterial activity in mice. No noticeable organ damage was captured from H&E-staining organ slices, suggesting the promise of using PQTs for in vivo applications. The results of this study demonstrated the interaction between bacteria and PLGA-based nanoparticles, providing encouragement for conducting further investigations on properties and antimicrobial activity of the PQTs in clinical application.

  17. Quercetin-Based Modified Porous Silicon Nanoparticles for Enhanced Inhibition of Doxorubicin-Resistant Cancer Cells.

    PubMed

    Liu, Zehua; Balasubramanian, Vimalkumar; Bhat, Chinmay; Vahermo, Mikko; Mäkilä, Ermei; Kemell, Marianna; Fontana, Flavia; Janoniene, Agne; Petrikaite, Vilma; Salonen, Jarno; Yli-Kauhaluoma, Jari; Hirvonen, Jouni; Zhang, Hongbo; Santos, Hélder A

    2017-02-01

    One of the most challenging obstacles in nanoparticle's surface modification is to achieve the concept that one ligand can accomplish multiple purposes. Upon such consideration, 3-aminopropoxy-linked quercetin (AmQu), a derivative of a natural flavonoid inspired by the structure of dopamine, is designed and subsequently used to modify the surface of thermally hydrocarbonized porous silicon (PSi) nanoparticles. This nanosystem inherits several advanced properties in a single carrier, including promoted anticancer efficiency, multiple drug resistance (MDR) reversing, stimuli-responsive drug release, drug release monitoring, and enhanced particle-cell interactions. The anticancer drug doxorubicin (DOX) is efficiently loaded into this nanosystem and released in a pH-dependent manner. AmQu also effectively quenches the fluorescence of the loaded DOX, thereby allowing the use of the nanosystem for monitoring the intracellular drug release. Furthermore, a synergistic effect with the presence of AmQu is observed in both normal MCF-7 and DOX-resistant MCF-7 breast cancer cells. Due to the similar structure as dopamine, AmQu may facilitate both the interaction and internalization of PSi into the cells. Overall, this PSi-based platform exhibits remarkable superiority in both multifunctionality and anticancer efficiency, making this nanovector a promising system for anti-MDR cancer treatment.

  18. Anti-cancer evaluation of quercetin embedded PLA nanoparticles synthesized by emulsified nanoprecipitation.

    PubMed

    Pandey, Sanjeev K; Patel, Dinesh K; Thakur, Ravi; Mishra, Durga P; Maiti, Pralay; Haldar, Chandana

    2015-04-01

    This study was carried out to synthesize quercetin (Qt) embedded poly(lactic acid) (PLA) nanoparticles (PLA-Qt) and to evaluate anti-cancer efficacy of PLA-Qt by using human breast cancer cells. PLA-Qt were synthesized by using novel emulsified nanoprecipitation technique with varying dimension of 32 ± 8 to 152 ± 9 nm of PLA-Qt with 62 ± 3% (w/w) entrapment efficiency by varying the concentration of polymer, emulsifier, drug and preparation temperature. The dimension of PLA-Qt was measured through transmission electron microscopy indicating larger particle size at higher concentration of PLA. The release rate of Qt from PLA-Qt was found to be more sustained for larger particle dimension (152 ± 9 nm) as compared to smaller particle dimension (32 ± 8 nm). Interaction between Qt and PLA was verified through spectroscopic and calorimetric methods. Delayed diffusion and stronger interaction in PLA-Qt caused the sustained delivery of Qt from the polymer matrix. In vitro cytotoxicity study indicate the killing of ∼ 50% breast cancer cells in two days at 100 μg/ml of drug concentration while the ∼ 40% destruction of cells require 5 days for PLA-Qt (46 ± 6 nm; 20mg/ml of PLA). Thus our results propose anticancer efficacy of PLA-Qt nanoparticles in terms of its sustained release kinetics revealing novel vehicle for the treatment of cancer. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Hydrolytic cleavage of DNA by quercetin zinc(II) complex.

    PubMed

    Jun, Tan; Bochu, Wang; Liancai, Zhu

    2007-03-01

    Quercetin zinc(II) complex was investigated focusing on its hydrolytic activity toward DNA. The complex successfully promotes the cleavage of plasmid DNA, producing single and double DNA strand breaks. The amount of conversion of supercoiled form (SC) of plasmid to the nicked circular form (NC) depends on the concentration of the complex as well as the duration of incubation of the complex with DNA. The rate of conversion of SC to NC is 1.68x10(-4) s(-1) at pH 7.2 in the presence of 100 microM of the complex. The hydrolytic cleavage of DNA by the complex is supported by the evidence from free radical quenching, thiobarbituric acid-reactive substances (TBARS) assay, and T4 ligase ligation.

  20. Hydrolytic cleavage of DNA by quercetin manganese(II) complexes.

    PubMed

    Jun, Tan; Bochu, Wang; Liancai, Zhu

    2007-04-01

    Quercetin manganese(II) complexes were investigated focusing on its DNA hydrolytic activity. The complexes successfully promote the cleavage of plasmid DNA, producing single and double DNA strand breaks. The amount of conversion of supercoiled form (SC) of plasmid DNA to the nicked circular form (NC) depends on the concentration of the complex as well as the duration of incubation of the complexes with DNA. The maximum rate of conversion of the supercoiled form to the nicked circular form at pH 7.2 in the presence of 100 microM of the complexes is found to be 1.32 x 10(-4) s(-1). The hydrolytic cleavage of DNA by the complexes was supported by the evidence from free radical quenching, thiobarbituric acid-reactive substances (TBARS) assay and T4 ligase ligation.

  1. Ameliorative Effect of Quercetin on Neurochemical and Behavioral Deficits in Rotenone Rat Model of Parkinson's Disease: Modulating Autophagy (Quercetin on Experimental Parkinson's Disease).

    PubMed

    El-Horany, Hemat E; El-Latif, Rania N Abd; ElBatsh, Maha M; Emam, Marwa N

    2016-07-01

    Autophagy is necessary for neuronal homeostasis and its dysfunction has been implicated in Parkinson's disease (PD) as it can exacerbate endoplasmic reticulum (ER) stress and ER stress-induced apoptosis. Quercetin is a flavonoid known for its neuroprotective and antioxidant effects. The present study investigated the protective, autophagy-modulating effects of quercetin in the rotenone rat model of PD. Rotenone was intraperitoneally injected at dose of 2 ml/kg/day for 4 weeks. Simultaneous intraperitoneal injection of quercetin was given at a dose of 50 mg/kg/day also for 4 weeks. Neurobehavioral changes were studied. Oxidative/antioxidant status, C/EBP homologous protein (CHOP), Beclin-1, and dopamine levels were assessed. DNA fragmentation and histopathological changes were evaluated. This research work revealed that quercetin significantly attenuated rotenone-induced behavioral impairment, augmented autophagy, ameliorated ER stress- induced apoptosis with attenuated oxidative stress. From the current study, quercetin can act as an autophagy enhancer in PD rat model and modulates the microenvironment that leads to neuronal death.

  2. Unlike Quercetin Glycosides, Cyanidin Glycoside in Red Leaf Lettuce Responds More Sensitively to Increasing Low Radiation Intensity before than after Head Formation Has Started

    PubMed Central

    2014-01-01

    This study investigated the effect of low-level photosynthetic photon flux density (PPFD; 43–230 μmol m–2 s–1) on the major phenolic compounds of red leaf lettuce in three growth stages, before, during, and after head formation, using HPLC-DAD-ESI-MS2 and evaluating via multiple regression analysis. Generally, the light-related increase of flavonoid glycosides was structure and growth stage-dependent. In detail, an interaction was detected between plant age and PPFD regarding cyanidin-3-O-(6″-O-malonyl)-glucoside concentration: the increase was strongest before head formation. The relationship between PPFD and quercetin-3-O-(6″-O-malonyl)-glucoside concentration was linear, whereas the increase of quercetin-3-O-glucoside and -3-O-glucuronide concentrations abated with increasing PPFD. Independent of growth stage, the caffeic acid derivatives concentration was not related to PPFD. All major phenolic compounds decreased with plant age. These results show the differential regulation of cyanidin, quercetin, and caffeic acid derivatives in lettuce, although closely connected biosynthetically, and emphasize the importance of ontogeny in the study of plant physiology. PMID:24382136

  3. The bioflavonoid quercetin synergises with PPAR-γ agonist pioglitazone in reducing angiotensin-II contractile effect in fructose-streptozotocin induced diabetic rats.

    PubMed

    Kunasegaran, Thubasni; Mustafa, Mohd Rais; Murugan, Dharmani Devi; Achike, Francis I

    2016-06-01

    This study investigated the effects of combined minimal concentrations of quercetin and pioglitazone on angiotensin II-induced contraction of the aorta from fructose-streptozotocin (F-STZ)-induced type 2 diabetic rats and the possible role of superoxide anions (O2(-)) and nitric oxide (NO) in their potential therapeutic interaction. Contractile responses to Ang II of aortic rings from Sprague-Dawley (SD) and F-STZ rats were tested following pre-incubation of the tissues in the vehicle (DMSO; 0.05%), quercetin (Q, 0.1 μM), pioglitazone (P, 0.1 μM) or their combination (P + Q; 0.1 μM each). The amount of superoxide anion was evaluated by lucigenin-enhanced chemiluminescence and dihydroethidium fluorescence, and NO by assay of total nitrate/nitrite, and 4-Amino-5-Methylamino-2',7'-Difluorofluorescein (DAF-FM) diacetate. The synergistic reduction of Ang II-induced contraction of diabetic but not normal aorta with minimally effective concentrations of P + Q occurs through inhibiting O2(-) and increasing NO bioavailability. This finding opens the possibility of maximal vascular protective/antidiabetic effects with low dose pioglitazone combined with quercetin, thus minimizing the risk of adverse effects.

  4. Quercetin 7-O-glucoside suppresses nitrite-induced formation of dinitrosocatechins and their quinones in catechin/nitrite systems under stomach simulating conditions.

    PubMed

    Morina, Filis; Takahama, Umeo; Yamauchi, Ryo; Hirota, Sachiko; Veljovic-Jovanovic, Sonja

    2015-01-01

    Foods of plant origin contain flavonoids. In the adzuki bean, (+)-catechin, quercetin 3-O-rutinoside (rutin), and quercetin 7-O-β-D-glucopyranoside (Q7G) are the major flavonoids. During mastication of foods prepared from the adzuki bean, the flavonoids are mixed with saliva and swallowed into the stomach. Here we investigated the interactions between Q7G and (+)-catechin at pH 2, which may proceed in the stomach after the ingestion of foods prepared from the adzuki bean. Q7G reacted with nitrous acid producing nitric oxide (˙NO) and a glucoside of 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone. (+)-Catechin reacted with nitrous acid producing ˙NO and 6,8-dinitrosocatechin. The production of the dinitrosocatechin was partly suppressed by Q7G, and the suppression resulted in the enhancement of Q7G oxidation. 6,8-Dinitrosocatechin reacted further with nitrous acid generating the o-quinone, and the quinone formation was effectively suppressed by Q7G. In the flavonoids investigated, the suppressive effect decreased in the order Q7G≈quercetin>kaempferol>quercetin 4'-O-glucoside>rutin. Essentially the same results were obtained when (-)-epicatechin was used instead of (+)-catechin. The results indicate that nitrous acid-induced formation of 6,8-dinitrosocatechins and the o-quinones can be suppressed by flavonols in the stomach, and that both a hydroxyl group at C3 and ortho-hydroxyl groups in the B-ring are required for efficient suppression.

  5. Ameliorative effect of quercetin against arsenic-induced sperm DNA damage and daily sperm production in adult male rats.

    PubMed

    Jahan, Sarwat; Rehman, Saima; Ullah, Hizb; Munawar, Asma; Ain, Qurat Ul; Iqbal, Tariq

    2016-01-01

    In this study, the protective effect of quercetin was evaluated against arsenic induced reproductive ailments in male rats. For this purpose, male rats (n = 5/group) weighing 180-250 g were used. First group served as control, second group received arsenic (50 ppm) in drinking water. Third group was treated with quercetin (50 mg/kg) alone, while fourth group received arsenic + quercetin. All treatments were carried out for 49 days. After treatment, animals were killed by decapitation; testis and epididymis were dissected out. Right epididymis was minced immediately for comet assay, while left epididymis was processed for histology. Similarly, right testis was homogenized for estimation of daily sperm production (DSP) and detection of metal concentration. The results of our research revealed that arsenic treatment did not cause any significant change in body weight and testicular volume. Quercetin treatment significantly prevented tissue deposition of arsenic within the testis. Arsenic treatment caused a significant reduction in DSP, however, in the arsenic + quercetin-treated group and quercetin alone-treated group, DSP was significantly high as compared to the arsenic-treated group. Histological study of epididymis showed empty lumen in arsenic-treated group while in arsenic + quercetin-treated group and quercetin alone-treated group, lumen were filled with sperm and were comparable to control. Sperm DNA damage, induced by arsenic, was significantly reversed toward control levels by supplementation of quercetin. These results suggest that quercetin not only prevents deposition of arsenic in tissues, but can also protect the sperm DNA damage.

  6. Quercetin-induced downregulation of phospholipase D1 inhibits proliferation and invasion in U87 glioma cells

    SciTech Connect

    Park, Mi Hee; Min, Do Sik

    2011-09-09

    Highlights: {yields} Quercetin, a bioactive flavonoid, suppresses expression and enzymatic activity of phospholipase D1. {yields} Quercetin abolishes NFkB-induced phospholipase D1 expression via inhibition of NFkB transactivation. {yields} Quercetin-induced suppression of phospholipase D1 inhibits invasion and proliferation of human glioma cells. -- Abstract: Phospholipase D (PLD) has been recognized as a regulator of cell proliferation and tumorigenesis, but little is known about the molecules regulating PLD expression. Thus, the identification of small molecules inhibiting PLD expression would be an important advance in PLD-mediated physiology. Quercetin, a ubiquitous bioactive flavonoid, is known to inhibit proliferation and induce apoptosis in a variety of cancer cells. In the present study, we examined the effect of quercetin on the expression of PLD in U87 glioma cells. Quercetin significantly suppressed the expression of PLD1 at the transcriptional level. Moreover, quercetin abolished the protein expression of PLD1 in a time and dose-dependent manner, as well as inhibited PLD activity. Quercetin suppressed NF{kappa}B-induced PLD1 expression via inhibition of NFkB transactivation. Furthermore, quercetin inhibited activation and invasion of metalloproteinase-2 (MMP-2), a key modulator of glioma cell invasion, induced by phosphatidic acid (PA), a product of PLD activity. Taken together these data demonstrate that quercetin abolishes PLD1 expression and subsequently inhibits invasion and proliferation of glioma cells.

  7. Quercetin induces cell apoptosis of myeloma and displays a synergistic effect with dexamethasone in vitro and in vivo xenograft models.

    PubMed

    He, Donghua; Guo, Xing; Zhang, Enfan; Zi, Fuming; Chen, Jing; Chen, Qingxiao; Lin, Xuanru; Yang, Li; Li, Yi; Wu, Wenjun; Yang, Yang; He, Jingsong; Cai, Zhen

    2016-07-19

    Quercetin, a kind of dietary flavonoid, has shown its anticancer activity in many kinds of cancers including hematological malignancies (acute myelogenous leukemia, chronic myelogenous leukemia, chronic lymphocytic leukemia, and MM) in vitro and in vivo. However, its effects on MM need further investigation. In this study, MM cell lines were treated with quercetin alone or in combination with dexamethasone. In order to observe the effects in vivo, a xenograft model of human myeloma was established. Quercetin inhibited proliferation of MM cells (RPMI8226, ARP-1, and MM.1R) by inducing cell cycle arrest in the G2/M phase and apoptosis. Western blot showed that quercetin downregulated c-myc expression and upregulated p21 expression. Quercetin also activated caspase-3, caspase-9, and poly(ADP-ribose)polymerase 1. Caspase inhibitors partially blocked apoptosis induced by quercetin. Furthermore, quercetin combined with dexamethasone significantly increased MM cell apoptosis. In vivo xenograft models, quercetin obviously inhibited tumor growth. Caspase-3 was activated to a greater extent when quercetin was combined with dexamethasone. In conclusion, quercetin alone or in combination with dexamethasone may be an effective therapy for MM.

  8. An insight into the potentially old-wonder molecule-quercetin: the perspectives in foresee.

    PubMed

    Rani, Nidhi; Velan, Lakshmi Palanisamy Thanga; Vijaykumar, Saravanan; Arunachalam, Annamalai

    2015-09-09

    Use of phyto-medicine and digitalization of phyto-compounds has been fallen enthralling field of science in recent years. Quercetin, a flavonoid with brilliant citron yellow pigment, is typically found in fruits and leafy vegetables in reasonable amount. Quercetin's potentials as an antioxidant, immune-modulator, antiinflammatory, anti-cancer, and others have been the subject of interest in this review. Although, profiling the insights in to the molecular characterization of quercetin with various targets provided the loop-holes in understanding the knowledge for the aforementioned mechanisms, still necessitates research globally to unearth it completely. Thus, the available science on the synthesis and significant role played by the old molecule - quercetin which does wonders even now have been vividly explained in the present review to benefit the scientific community.

  9. Deltamethrin Induced Alteration of Biochemical Parameters in Channa punctata, Bloch and its Amelioration by Quercetin.

    PubMed

    Bhattacharjee, Parmita; Das, Suchismita

    2017-06-01

    We tested the impacts of pyrethroid pesticide deltamethrin and its amelioration by a flavonoid, quercetin, using tissue macromolecules (protein, amino acid, carbohydrate and glycogen) and antioxidant enzymes (superoxide dismutase, catalase and peroxidase) as biomarkers, on fish, Channa punctata, gill and liver. Our study proved that quercetin supplement alone, in the absence of pesticide, might be detrimental to fish health, in terms of depletion of major tissue macromolecules, but, such supplement may be beneficial to fish with pesticide associated oxidative stress. Multivariate analyses predicted that the antioxidant enzymes and lipid peroxidation were closely associated biomarkers; whereas tissue macromolecules formed a different cluster. Hence, oxidative stress biomarkers in fish can be considered a valuable tool in assessment of deltamethrin stress and its amelioration by quercetin. The work can pave the way for further research in establishing quercetin as a probable curative agent.

  10. Quercetin does not alter the oral bioavailability of Atorvastatin in rats.

    PubMed

    Koritala, Rekha; Challa, Siva Reddy; Ragam, Satheesh Kumar; Geddam, Lal Babu; Venkatesh Reddy Challa, Venkatesh Reddy; Devi, Renuka; Sattenapalli, Srinu; Babu, Narendra

    2015-09-01

    The study was undertaken to evaluate the effect of Quercetin on the pharmacokinetics of Atorvastatin Calcium. In-vivo Pharmacokinetic studies were performed on rats in a single dose study and multiple dose study. Rats were treated with Quercetin (10 mg/kg) and Atorvastatin Calcium (20 mg/kg) orally and blood samples were collected at (0) pretreatment and 0.5, 1, 1.5, 2, 2.5, 3, 4, 8, 12, 24 hours post treatment. Plasma concentrations of Atorvastatin were estimated by HPLC method. Quercetin treatment did not significantly alter the pharmacokinetic parameters of atorvastatin like AUC(0-24), AUC(0-α) , T(max), C(max) and T(½) in both single dose and multiple dose studies of Atorvastatin Calcium. Quercetin does not alter the oral bioavailability of Atorvastatin Calcium in rats.

  11. Quercetin inhibits the migration and proliferation of astrocytes in wound healing.

    PubMed

    Yuan, Zhaohu; Yao, Fang; Hu, Ziyou; Sun, Shumei; Wu, Bingyi

    2015-05-06

    A previous study showed that quercetin inhibits astrogliosis in a scratch-wound model, but did not identify the underlying mechanisms. Here, we show that quercetin exerts no effect on apoptosis or the viability of astrocytes, but significantly inhibits their proliferation, arresting them in the G1 phase and decreasing the percentage of cells in the S and G2 phase. In addition, we found that quercetin significantly decreased the phosphorylation of ERK1/2 and FAK, a downstream ERK signaling protein. Inhibition of this pathway with U0126, an inhibitor of MAP kinase, retarded wound closure, whereas sustained p-ERK1/2 activation, induced by vanadate, restored astrocyte migration. Our findings thus indicate that quercetin inhibits healing in the scratch-wound model of primary astrocytes in two ways: blockade of the G1 to S phase cell cycle transition and inhibition of the ERK/FAK signaling pathway, which may contribute toward decreasing astroglial scar formation in vivo.

  12. Quercetin induces apoptosis of Trypanosoma brucei gambiense and decreases the proinflammatory response of human macrophages.

    PubMed

    Mamani-Matsuda, Maria; Rambert, Jérôme; Malvy, Denis; Lejoly-Boisseau, Hélène; Daulouède, Sylvie; Thiolat, Denis; Coves, Sara; Courtois, Pierrette; Vincendeau, Philippe; Mossalayi, M Djavad

    2004-03-01

    In addition to parasite spread, the severity of disease observed in cases of human African trypanosomiasis (HAT), or sleeping sickness, is associated with increased levels of inflammatory mediators, including tumor necrosis factor (TNF)-alpha and nitric oxide derivatives. In the present study, quercetin (3,3',4',5,7-pentahydroxyflavone), a potent immunomodulating flavonoid, was shown to directly induce the death of Trypanosoma brucei gambiense, the causative agent of HAT, without affecting normal human cell viability. Quercetin directly promoted T. b. gambiense death by apoptosis as shown by Annexin V binding. In addition to microbicidal activity, quercetin induced dose-dependent decreases in the levels of TNF-alpha and nitric oxide produced by activated human macrophages. These results highlight the potential use of quercetin as an antimicrobial and anti-inflammatory agent for the treatment of African trypanomiasis.

  13. The Best Extraction Technique for Kaempferol and Quercetin Isolation from Guava Leaves (Psidium guajava)

    NASA Astrophysics Data System (ADS)

    Batubara, I.; Suparto, I. H.; Wulandari, N. S.

    2017-03-01

    Guava leaves contain various compounds that have biological activity such as kaempferol and quercetin as anticancer. Twelve extraction techniques were performed to obtain the best extraction technique to isolate kaempferol and quercetin from the guava leaves. Toxicity of extracts was tested against Artemia salina larvae. All extracts were toxic (LC50 value less than 1000 ppm) except extract of direct soxhletation on guava leaves, and extract of sonication and soxhletation using n-hexane. The extract with high content of total phenols and total flavonoids, low content of tannins, intense color of spot on thin layer chromatogram was selected for high performance liquid chromatography analysis. Direct sonication of guava leaves was chosen as the best extraction technique with kampferol and quercetin content of 0.02% and 2.15%, respectively. In addition to high content of kaempferol and quercetin, direct sonication was chosen due to the shortest extraction time, lesser impurities and high toxicity.

  14. Time-course regulation of quercetin on cell survival/proliferation pathways in human hepatoma cells.

    PubMed

    Granado-Serrano, Ana Belén; Angeles Martín, María; Bravo, Laura; Goya, Luis; Ramos, Sonia

    2008-04-01

    Quercetin, a dietary flavonoid, has been shown to possess anticarcinogenic properties, but the precise molecular mechanisms of action are not thoroughly elucidated. This study was aimed at investigating the time-course regulation effect of quercetin on survival/proliferation pathways in a human hepatoma cell line (HepG2). Quercetin induced a significant time-dependent inactivation of the major survival signaling proteins, i. e., phosphatidylinositol 3-kinase (PI 3-kinase)/protein kinase B (AKT), extracellular regulated kinase (ERK), protein kinase C-alpha (PKC-alpha), in concert with a time-dependent activation of key death-related signals: c-jun amino-terminal kinase (JNK) and PKC-delta. These data suggest that quercetin exerts a tight regulation of survival/proliferation pathways that requires the integration of different signals and persists over time, being the balance of these regulatory signals what determines the fate of HepG2 cells.

  15. Antiulcer and gastroprotective effects of quercetin: a gross and histologic study.

    PubMed

    Alarcón de la Lastra, C; Martín, M J; Motilva, V

    1994-01-01

    This study was designed to determine the cytoprotective properties of quercetin and the involvement of endogenous prostaglandins in mucosal injury produced by absolute ethanol. Gastric glands were also analyzed histologically. Oral pretreatment with the highest dose of quercetin (200 mg/kg), 120 min before absolute ethanol, was most effective in necrosis prevention. Subcutaneous administration of indomethacin (10 mg/kg) to the animals treated with quercetin (200 mg/kg) partially inhibited gastric protection. All treated groups showed a marked increase in the amount of gastric mucus although this increase was less in animals pretreated with indomethacin. Total proteins and the hexosamine content decreased in the groups receiving indomethacin. The histomorphometric evaluation of the gastric damage confirmed a significant increase in mucus production accompanied by a parallel reduction of gastric lesions with the highest dose of quercetin tested.

  16. Regulation of Wnt signaling activity for growth suppression induced by quercetin in 4T1 murine mammary cancer cells.

    PubMed

    Kim, Haesung; Seo, Eun-Min; Sharma, Ashish R; Ganbold, Bilguun; Park, Jongbong; Sharma, Garima; Kang, Young-Hee; Song, Dong-Keun; Lee, Sang-Soo; Nam, Ju-Suk

    2013-10-01

    Quercetin is a promising chemopreventive agent against cancer that inhibits tumor progression by inducing cell cycle arrest and promoting apoptotic cell death. Recently, the Wnt/β-catenin signaling pathway has been implicated in mammary tumorigenesis, where its abnormal activation is associated with the development of breast cancer. Thus, the objective of this study was to examine the biological activities of quercetin against mammary cancer cells, and to determine whether quercetin could regulate the Wnt/β-catenin signaling pathway. Quercetin showed dose-dependent inhibition of cell growth and induced apoptosis in 4T1 cells. Treatment of 20 µM quercetin suppressed ~50% of basal TopFlash luciferase activity. Moreover, the inhibitory effect of quercetin on the Wnt/β-catenin signaling pathway was confirmed by the reduced stabilization of the β-catenin protein. Among various antagonists screened for the Wnt/β-catenin signaling pathway, the expression of DKK1, 2 and 3 was induced after treatment with 20 µM of quercetin. Stimulation with recombinant DKK1 protein, showed suppressive cell growth of mammary cancer cells instead of quercetin. When 4T1 cells were treated with recombinant Wnt3a or LiCl along with quercetin, both stimulators for the Wnt/β-catenin signaling pathway were able to restore the suppressed cell viability by quercetin. Thus, our data suggest that quercetin exerts its anticancer activity through the downregulation of Wnt/β-catenin signaling activity. These results indicate for the first time that quercetin decreases cell viability and induces apoptosis in murine mammary cancer cells, which is possibly mediated by DKK-dependent inhibition of the Wnt/β-catenin signaling pathway. In conclusion, our findings suggest that quercetin has great potential value as chemotherapeutic agent for cancer treatment, especially in breast cancer controlled by Wnt/β-catenin signaling activity.

  17. Quercetin and Quercetin-Rich Red Onion Extract Alter Pgc-1α Promoter Methylation and Splice Variant Expression

    PubMed Central

    Devarshi, Prasad P.; Jones, Aarin D.; Taylor, Erin M.; Stefanska, Barbara

    2017-01-01

    Pgc-1α and its various isoforms may play a role in determining skeletal muscle mitochondrial adaptations in response to diet. 8 wks of dietary supplementation with the flavonoid quercetin (Q) or red onion extract (ROE) in a high fat diet (HFD) ameliorates HFD-induced obesity and insulin resistance in C57BL/J mice while upregulating Pgc-1α and increasing skeletal muscle mitochondrial number and function. Here, mice were fed a low fat (LF), high fat (HF), high fat plus quercetin (HF + Q), or high fat plus red onion extract (HF + RO) diet for 9 wks and skeletal muscle Pgc-1α isoform expression and DNA methylation were determined. Quantification of various Pgc-1α isoforms, including isoforms Pgc-1α-a, Pgc-1α-b, Pgc-1α-c, Pgc-1α4, total NT-Pgc-1α, and FL-Pgc-1α, showed that only total NT-Pgc-1α expression was increased in LF, HF + Q, and HF + RO compared to HF. Furthermore, Q supplementation decreased Pgc-1α-a expression compared to LF and HF, and ROE decreased Pgc-1α-a expression compared to LF. FL-Pgc-1α was decreased in HF + Q and HF + RO compared to LF and HF. HF exhibited hypermethylation at the −260 nucleotide (nt) in the Pgc-1α promoter. Q and ROE prevented HFD-induced hypermethylation. −260 nt methylation levels were associated with NT-Pgc-1α expression only. Pgc-1α isoform expression may be epigenetically regulated by Q and ROE through DNA methylation. PMID:28191013

  18. Anticancer effect and mechanism of polymer micelle-encapsulated quercetin on ovarian cancer

    NASA Astrophysics Data System (ADS)

    Gao, Xiang; Wang, Bilan; Wei, Xiawei; Men, Ke; Zheng, Fengjin; Zhou, Yingfeng; Zheng, Yu; Gou, Maling; Huang, Meijuan; Guo, Gang; Huang, Ning; Qian, Zhiyong; Wei, Yuquan

    2012-10-01

    Encapsulation of hydrophobic agents in polymer micelles can improve the water solubility of cargos, contributing to develop novel drugs. Quercetin (QU) is a hydrophobic agent with potential anticancer activity. In this work, we encapsulated QU into biodegradable monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles and tried to provide proof-of-principle for treating ovarian cancer with this nano-formulation of quercetin. These QU loaded MPEG-PCL (QU/MPEG-PCL) micelles with drug loading of 6.9% had a mean particle size of 36 nm, rendering the complete dispersion of quercetin in water. QU inhibited the growth of A2780S ovarian cancer cells on a dose dependent manner in vitro. Intravenous administration of QU/MPEG-PCL micelles significantly suppressed the growth of established xenograft A2780S ovarian tumors through causing cancer cell apoptosis and inhibiting angiogenesis in vivo. Furthermore, the anticancer activity of quercetin on ovarian cancer cells was studied in vitro. Quercetin treatment induced the apoptosis of A2780S cells associated with activating caspase-3 and caspase-9. MCL-1 downregulation, Bcl-2 downregulation, Bax upregulation and mitochondrial transmembrane potential change were observed, suggesting that quercetin may induce apoptosis of A2780S cells through the mitochondrial apoptotic pathway. Otherwise, quercetin treatment decreased phosphorylated p44/42 mitogen-activated protein kinase and phosphorylated Akt, contributing to inhibition of A2780S cell proliferation. Our data suggested that QU/MPEG-PCL micelles were a novel nano-formulation of quercetin with a potential clinical application in ovarian cancer therapy.

  19. Quercetin induces hepatic lipid omega-oxidation and lowers serum lipid levels in mice.

    PubMed

    Hoek-van den Hil, Elise F; Keijer, Jaap; Bunschoten, Annelies; Vervoort, Jacques J M; Stankova, Barbora; Bekkenkamp, Melissa; Herreman, Laure; Venema, Dini; Hollman, Peter C H; Tvrzicka, Eva; Rietjens, Ivonne M C M; van Schothorst, Evert M

    2013-01-01

    Elevated circulating lipid levels are known risk factors for cardiovascular diseases (CVD). In order to examine the effects of quercetin on lipid metabolism, mice received a mild-high-fat diet without (control) or with supplementation of 0.33% (w/w) quercetin for 12 weeks. Gas chromatography and (1)H nuclear magnetic resonance were used to quantitatively measure serum lipid profiles. Whole genome microarray analysis of liver tissue was used to identify possible mechanisms underlying altered circulating lipid levels. Body weight, energy intake and hepatic lipid accumulation did not differ significantly between the quercetin and the control group. In serum of quercetin-fed mice, triglycerides (TG) were decreased with 14% (p<0.001) and total poly unsaturated fatty acids (PUFA) were increased with 13% (p<0.01). Palmitic acid, oleic acid, and linoleic acid were all decreased by 9-15% (p<0.05) in quercetin-fed mice. Both palmitic acid and oleic acid can be oxidized by omega (ω)-oxidation. Gene expression profiling showed that quercetin increased hepatic lipid metabolism, especially ω-oxidation. At the gene level, this was reflected by the up-regulation of cytochrome P450 (Cyp) 4a10, Cyp4a14, Cyp4a31 and Acyl-CoA thioesterase 3 (Acot3). Two relevant regulators, cytochrome P450 oxidoreductase (Por, rate limiting for cytochrome P450s) and the transcription factor constitutive androstane receptor (Car; official symbol Nr1i3) were also up-regulated in the quercetin-fed mice. We conclude that quercetin intake increased hepatic lipid ω-oxidation and lowered corresponding circulating lipid levels, which may contribute to potential beneficial effects on CVD.

  20. Quercetin Induces Hepatic Lipid Omega-Oxidation and Lowers Serum Lipid Levels in Mice

    PubMed Central

    Hoek-van den Hil, Elise F.; Keijer, Jaap; Bunschoten, Annelies; Vervoort, Jacques J. M.; Stankova, Barbora; Bekkenkamp, Melissa; Herreman, Laure; Venema, Dini; Hollman, Peter C. H.; Tvrzicka, Eva; Rietjens, Ivonne M. C. M.; van Schothorst, Evert M.

    2013-01-01

    Elevated circulating lipid levels are known risk factors for cardiovascular diseases (CVD). In order to examine the effects of quercetin on lipid metabolism, mice received a mild-high-fat diet without (control) or with supplementation of 0.33% (w/w) quercetin for 12 weeks. Gas chromatography and 1H nuclear magnetic resonance were used to quantitatively measure serum lipid profiles. Whole genome microarray analysis of liver tissue was used to identify possible mechanisms underlying altered circulating lipid levels. Body weight, energy intake and hepatic lipid accumulation did not differ significantly between the quercetin and the control group. In serum of quercetin-fed mice, triglycerides (TG) were decreased with 14% (p<0.001) and total poly unsaturated fatty acids (PUFA) were increased with 13% (p<0.01). Palmitic acid, oleic acid, and linoleic acid were all decreased by 9–15% (p<0.05) in quercetin-fed mice. Both palmitic acid and oleic acid can be oxidized by omega (ω)-oxidation. Gene expression profiling showed that quercetin increased hepatic lipid metabolism, especially ω-oxidation. At the gene level, this was reflected by the up-regulation of cytochrome P450 (Cyp) 4a10, Cyp4a14, Cyp4a31 and Acyl-CoA thioesterase 3 (Acot3). Two relevant regulators, cytochrome P450 oxidoreductase (Por, rate limiting for cytochrome P450s) and the transcription factor constitutive androstane receptor (Car; official symbol Nr1i3) were also up-regulated in the quercetin-fed mice. We conclude that quercetin intake increased hepatic lipid ω-oxidation and lowered corresponding circulating lipid levels, which may contribute to potential beneficial effects on CVD. PMID:23359794

  1. Quercetin attenuates the ischemia reperfusion induced COX-2 and MPO expression in the small intestine mucosa.

    PubMed

    Tóth, Štefan; Jonecová, Zuzana; Čurgali, Kristína; Maretta, Milan; Šoltés, Ján; Švaňa, Martin; Kalpadikis, Theodore; Caprnda, Martin; Adamek, Mariusz; Rodrigo, Luis; Kruzliak, Peter

    2017-08-28

    Quercetin, the active substance of tea, fruits and vegetables, exerts a broad spectrum of pharmacological activities and is considered to have potential therapeutic application. The present study was designed to investigate the beneficial effect of quercetin against experimental ischemia- reperfusion (IR) injury of the small intestine in rats. Quercetin was administrated intraperitoneally 30min before 1h ischemia of superior mesenteric artery with following reperfusion periods lasting 1, 4 and 24h. The male specific pathogen-free Charles River Wistar rats were used (n=45). In acute phase, 4h after start of reperfusion, the quercetin induced a significant decrease in mucosal injury index (p<0.05) accompanied by a significant decrease in cyclooxygenase-2 (COX-2) expression in the epithelial lining of the intestinal villi in comparison with the control group (p<0.01). In the epithelium of the intestinal glands, COX-2 expression resulting from IR injury significantly increased regardless quercetin application (in control group p<0.001; in quercetin group p<0.05), but in quercetin group, significant decrease in it during 24h of reperfusion in a late phase of IR injury was detected (p<0.001). Based on morphology of COX-2 positive cells, the COX-2 positivity was found particularly in goblet cells of the intestinal villi epithelium and enteroendocrine cells respectively, in the glandular epithelium. We concluded that quercetin application attenuated mucosal damage from IR injury by inhibiting neutrophil infiltration which was demonstrated by a lower number of myeloperoxidase positive cells in the lamina propria during both phases of IR injury and the significant decrease in that in a late phase after 24h of reperfusion (p<0.05). Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. Quercetin-Loaded Solid Lipid Nanoparticle Dispersion with Improved Physicochemical Properties and Cellular Uptake.

    PubMed

    Vijayakumar, Ajay; Baskaran, Rengarajan; Jang, Young Soo; Oh, Seung Hyun; Yoo, Bong Kyu

    2017-04-01

    The objective of this study was to formulate and characterize properties of solid lipid nanoparticle (SLN) dispersion containing quercetin. SLN was prepared by ultrasonication method using tripalmitin and lecithin as lipid core and then the surface was coated with chitosan. Entrapment efficiency was greater than 99%, and mean particle size of SLN was 110.7 ± 1.97 nm with significant increase in the coated SLN (c-SLN). Zeta potential was proportionally increased and reached plateau at 5% of chitosan coating with respect to tripalmitin. Differential scanning calorimetry showed disappearance of endothermic peak of quercetin in SLNs, indicating conversion of crystalline state to amorphous state. FTIR study of SLNs showed no change in the spectrum of quercetin, which indicates that the lipid and chitosan were not incompatible with quercetin. When coating amount was greater than 2.5% of tripalmitin, particle size and zeta potential were very stable even at 40°C up to 90 days. All SLN dispersions showed significantly faster release profile compared to pure quercetin powder. At pH 7.0, the release rate was increased in proportion to the coating amount. Interestingly, at pH 3.0, chitosan coating of 5.0% or greater decreased the rate. Cellular uptake of quercetin was performed using Caco-2 cells and showed that all SLN dispersions were significantly better than quercetin dispersed in distilled water. However, cellular uptake of quercetin from c-SLN was significantly lower than that from uncoated SLN.

  3. Effects of acute and chronic quercetin administration on methylphenidate-induced hyperlocomotion and oxidative stress.

    PubMed

    Kanazawa, Luiz K S; Vecchia, Débora D; Wendler, Etiéli M; Hocayen, Palloma de A S; Beirão, Paulo S; de Mélo, Manuela L; Dos Reis Lívero, Francislaine A; Corso, Claudia Rita; Stipp, Maria Carolina; Acco, Alexandra; Andreatini, Roberto

    2017-02-15

    Increases in protein kinase C (PKC) and oxidative stress have been related to mania. Drugs with antioxidant effects or inhibitory actions on PKC may have antimanic effects. The flavonoid quercetin has antioxidant and PKC-inhibiting effects that resemble those of lithium, the first-line treatment for mania in bipolar disorder. We hypothesized that quercetin may have antimanic-like effects in an animal model. In the present study, we investigated the effects of acute and chronic treatment with quercetin (2.5, 5, 10, and 40mg/kg, i.p.) in male Swiss mice that were subjected to methylphenidate (5mg/kg, i.p.)-induced hyperlocomotion, an animal model of mania. Lithium (100mg/kg, i.p.) and diazepam (5mg/kg, i.p.) were used as positive and negative controls, respectively. We also evaluated the effects of these treatments on methylphenidate-induced oxidative stress in the brain by measuring reduced glutathione (GSH) and lipid peroxidation (LPO) levels in the prefrontal cortex, hippocampus, and striatum. Acute and chronic (21-day) treatment with lithium and diazepam reduced methylphenidate-induced hyperlocomotion. Chronic but not acute treatment with quercetin (10 and 40mg/kg) blocked methylphenidate-induced hyperlocomotion. These effects of lithium and quercetin occurred at doses that did not alter spontaneous locomotor activity, whereas diazepam reduced spontaneous locomotor activity. Chronic treatment with lithium and quercetin blocked the methylphenidate-induced increase in LPO levels in the striatum. These results suggest that chronic quercetin treatment has antimanic-like and antioxidant effects, thus encouraging further studies of quercetin as a putative new antimanic drug. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Quercetin as an Emerging Anti-Melanoma Agent: A Four-Focus Area Therapeutic Development Strategy

    PubMed Central

    Harris, Zoey; Donovan, Micah G.; Branco, Gisele Morais; Limesand, Kirsten H.; Burd, Randy

    2016-01-01

    Replacing current refractory treatments for melanoma with new prevention and therapeutic approaches is crucial in order to successfully treat this aggressive cancer form. Melanoma develops from neural crest cells, which express tyrosinase – a key enzyme in the pigmentation pathway. The tyrosinase enzyme is highly active in melanoma cells and metabolizes polyphenolic compounds; tyrosinase expression thus makes feasible a target for polyphenol-based therapies. For example, quercetin (3,3′,4′,5,7-pentahydroxyflavone) is a highly ubiquitous and well-classified dietary polyphenol found in various fruits, vegetables, and other plant products including onions, broccoli, kale, oranges, blueberries, apples, and tea. Quercetin has demonstrated antiproliferative and proapoptotic activity in various cancer cell types. Quercetin is readily metabolized by tyrosinase into various compounds that promote anticancer activity; additionally, given that tyrosinase expression increases during tumorigenesis, and its activity is associated with pigmentation changes in both early- and late-stage melanocytic lesions, it suggests that quercetin can be used to target melanoma. In this review, we explore the potential of quercetin as an anti-melanoma agent utilizing and extrapolating on evidence from previous in vitro studies in various human malignant cell lines and propose a “four-focus area strategy” to develop quercetin as a targeted anti-melanoma compound for use as either a preventative or therapeutic agent. The four areas of focus include utilizing quercetin to (i) modulate cellular bioreduction potential and associated signaling cascades, (ii) affect transcription of relevant genes, (iii) regulate epigenetic processes, and (iv) develop effective combination therapies and delivery modalities/protocols. In general, quercetin could be used to exploit tyrosinase activity to prevent, and/or treat, melanoma with minimal additional side effects. PMID:27843913

  5. Quercetin as an Emerging Anti-Melanoma Agent: A Four-Focus Area Therapeutic Development Strategy.

    PubMed

    Harris, Zoey; Donovan, Micah G; Branco, Gisele Morais; Limesand, Kirsten H; Burd, Randy

    2016-01-01

    Replacing current refractory treatments for melanoma with new prevention and therapeutic approaches is crucial in order to successfully treat this aggressive cancer form. Melanoma develops from neural crest cells, which express tyrosinase - a key enzyme in the pigmentation pathway. The tyrosinase enzyme is highly active in melanoma cells and metabolizes polyphenolic compounds; tyrosinase expression thus makes feasible a target for polyphenol-based therapies. For example, quercetin (3,3',4',5,7-pentahydroxyflavone) is a highly ubiquitous and well-classified dietary polyphenol found in various fruits, vegetables, and other plant products including onions, broccoli, kale, oranges, blueberries, apples, and tea. Quercetin has demonstrated antiproliferative and proapoptotic activity in various cancer cell types. Quercetin is readily metabolized by tyrosinase into various compounds that promote anticancer activity; additionally, given that tyrosinase expression increases during tumorigenesis, and its activity is associated with pigmentation changes in both early- and late-stage melanocytic lesions, it suggests that quercetin can be used to target melanoma. In this review, we explore the potential of quercetin as an anti-melanoma agent utilizing and extrapolating on evidence from previous in vitro studies in various human malignant cell lines and propose a "four-focus area strategy" to develop quercetin as a targeted anti-melanoma compound for use as either a preventative or therapeutic agent. The four areas of focus include utilizing quercetin to (i) modulate cellular bioreduction potential and associated signaling cascades, (ii) affect transcription of relevant genes, (iii) regulate epigenetic processes, and (iv) develop effective combination therapies and delivery modalities/protocols. In general, quercetin could be used to exploit tyrosinase activity to prevent, and/or treat, melanoma with minimal additional side effects.

  6. Long-Term Quercetin Dietary Enrichment Partially Protects Dystrophic Skeletal Muscle

    PubMed Central

    Spaulding, Hannah R.; Ballmann, Christopher G.; Quindry, John C.; Selsby, Joshua T.

    2016-01-01

    Duchenne muscular dystrophy (DMD) results from a genetic lesion in the dystrophin gene and leads to progressive muscle damage. PGC-1α pathway activation improves muscle function and decreases histopathological injury. We hypothesized that mild disease found in the limb muscles of mdx mice may be responsive to quercetin-mediated protection of dystrophic muscle via PGC-1α pathway activation. To test this hypothesis muscle function was measured in the soleus and EDL from 14 month old C57, mdx, and mdx mice treated with quercetin (mdxQ; 0.2% dietary enrichment) for 12 months. Quercetin reversed 50% of disease-related losses in specific tension and partially preserved fatigue resistance in the soleus. Specific tension and resistance to contraction-induced injury in the EDL were not protected by quercetin. Given some functional gain in the soleus it was probed with histological and biochemical approaches, however, in dystrophic muscle histopathological outcomes were not improved by quercetin and suppressed PGC-1α pathway activation was not increased. Similar to results in the diaphragm from these mice, these data suggest that the benefits conferred to dystrophic muscle following 12 months of quercetin enrichment were underwhelming. Spontaneous activity at the end of the treatment period was greater in mdxQ compared to mdx indicating that quercetin fed mice were more active in addition to engaging in more vigorous activity. Hence, modest preservation of muscle function (specific tension) and elevated spontaneous physical activity largely in the absence of tissue damage in mdxQ suggests dietary quercetin may mediate protection. PMID:27977770

  7. Anti-Cancer Effect of Quercetin in Xenograft Models with EBV-Associated Human Gastric Carcinoma.

    PubMed

    Lee, Hwan Hee; Lee, Seulki; Shin, Yu Su; Cho, Miyeon; Kang, Hyojeung; Cho, Hyosun

    2016-09-26

    Licorice extracts have been widely used in herbal and folk medications. Glycyrrhiza contains diverse range of biological compounds including triterpenes (glycyrrhizin, glycyrrhizic acid) and flavonoids (quercetin, liquiritin, liquiritigenin, glabridin, licoricidin, isoliquiritigenin). The flavonoids in licorice are known to have strong anti-cancer activities. Quercetin, the most abundant flavonoid, has been shown to have anti-ulcer, anti-cancer, antioxidant, and anti-inflammatory properties. Latent Epstein-Barr virus (EBV) infection can lead to serious malignancies, such as, Burkitt's lymphoma, Hodgkin's disease and gastric carcinoma(GC), and (Epstein-Barr virus associated gastric carcinoma) EBVaGC is one of the most common EBV-associated cancers. In this study, the authors first examined the anti-cancer effects of quercetin and isoliquiritigenin in vivo xenograft animal models implanted with EBV(+) human gastric carcinoma (SNU719) or EBV(-) human gastric carcinoma (MKN74), and then explored the molecular mechanisms responsible for their anti-cancer activities. The results obtained showed that anti-cancer effect of quercetin was greater than isoliquiritigenin in mice injected with EBV(+) human gastric carcinoma (SNU719) cells. On the other hand, quercetin and isoliquiritigenin had similar anti-cancer effects in mice injected with EBV(-) human gastric carcinoma (MKN74) cells. Interestingly, quercetin inhibited EBV viral protein expressions, including EBNA-1 and LMP-2 proteins in tumor tissues from mice injected with EBV(+) human gastric carcinoma. Quercetin more effectively induced p53-dependent apoptosis than isoliquiritigenin in EBV(+) human gastric carcinoma, and this induction was correlated with increased expressions of the cleaved forms of caspase-3, -9, and Parp. In EBV(-)human gastric carcinoma (MKN74), both quercetin and isoliquiritigenin induced the expressions of p53, Bax, and Puma and the cleaved forms of caspase-3 and -9 and Parp at similar levels.

  8. A novel solid fluorescence method for the fast determination of quercetin in biological samples based on the quercetin-Al(III) complex imprinted polymer

    NASA Astrophysics Data System (ADS)

    Hu, Yufei; Feng, Ting; Li, Gongke

    2014-01-01

    In this work, a novel solid fluorescence method was proposed and applied to the fast determination of quercetin in urine and onion skin samples by using metal coordination imprinted polymer membrane, which was regarded as a recognition element. The quercetin-Al(III) imprinted polymer was immobilized in the microporous polypropylene fiber membrane via consecutive in situ polymerization. The CIP membrane had the porous, loose and layer upon layer structure. The CIP membrane was characterized by electron microscope photographs, infrared spectra, thermogravimetric analysis and solvent-resistant investigation. The extraction conditions including extraction solvent, extraction time, desorption solvent were optimized. Compared with MIP and NIP membrane, CIP membrane had been proved to be peculiar selective for quercetin even in presence of the structurally similar compounds such as kaempferol, rutin, naringenin and alpinetin. The CIP membrane was characteristic of high selectivity, stable and sensitive response to quercetin in polar environment. Under the optimum condition, there was a linear relationship between the state fluorescent response and the concentration of quercetin. The linear calibration range was over 0.02 mg L-1-0.80 mg L-1 with a detection limit of 5 μg L-1. The method was characteristic of flexible and good repeatability with relative standard deviation (RSD) of 4.1%. The proposed method was also successfully applied for the determination of quercetin in urine and onion skin samples without complicated pretreatment. The recoveries were 84.0-112.4% and RSDs varied from 1.5% to 6.8%. The results obtained by the proposed method agreed well with those obtained by HPLC method.

  9. Dietary quercetin supplementation increases serum antioxidant capacity and alters hepatic gene expression profile in rats.

    PubMed

    Zhao, Liting; Wu, Jianquan; Yang, Jijun; Wei, Jingyu; Gao, Weina; Guo, Changjiang

    2011-06-01

    The aim of this study was to determine the effect of quercetin on hepatic gene expression profile in rats. Twenty male Wistar rats were divided into the control group and the quercetin-treated group, in which a diet containing 0.5% quercetin was provided. After two weeks of feeding, serum and liver samples were collected. Biomarkers of oxidative stress, including serum ferric reducing antioxidant power (FRAP) values and levels of ascorbic acid, vitamin E (VE), glutathione (GSH) and malondialdehyde (MDA) were measured. The hepatic gene expression profile was examined using a microarray technique. The results showed that serum FRAP value, levels of ascorbic acid and VE were increased significantly, whereas serum levels of GSH and MDA were not changed significantly after quercetin supplementation. The microarray analysis revealed that some hepatic genes involved in phase 2 reaction, metabolism of cholesterol and homocysteine, and energy production were expressed differentially in response to quercetin administration. These findings provide a molecular basis for the elucidation of the actions played by quercetin in vivo.

  10. Development of an antioxidant biomaterial by promoting the deglycosylation of rutin to isoquercetin and quercetin.

    PubMed

    Cruz-Zúñiga, Johana M; Soto-Valdez, Herlinda; Peralta, Elizabeth; Mendoza-Wilson, Ana María; Robles-Burgueño, M Refugio; Auras, Rafael; Gámez-Meza, Nohemí

    2016-08-01

    Quercetin-3-O-rutinoside (rutin), quercetin-3-O-glucoside (isoquercetin) and quercetin have shown antioxidant, cytoprotective, vasoprotective, antiproliferative and antiinflammatory properties. The aim of this work was to determine the conversion of rutin to isoquercetin and quercetin during the production of poly(l-lactic acid) films with potential to deliver these flavonoids toward tissues, pharmaceuticals or food matrices. Three poly(l-lactic acid) formulations with 17.7, 39.6 and 39.1mg/g of rutin were prepared by the extrusion process. Processing temperatures (130-165°C) promoted the deglycosylation of rutin to produce isoquercetin and subsequently quercetin, identified by high performance liquid chromatography coupled to mass spectrometry. The effect of the process on the antioxidant activity of the films was determined by measuring the capacity to scavenge 2,2 diphenyl-1-picrylhydrazyl radicals. The material with the highest proportion of quercetin showed the highest antioxidant activity which could be used to produce delivering devices of the flavonoids to tissues, pharmaceuticals or food matrices.

  11. Bioconversion of quercetin and rutin and the cytotoxicity activities of the transformed products.

    PubMed

    Araújo, Kelly Carolina Frauzino; de M B Costa, Eula Maria; Pazini, Francine; Valadares, Marize Campos; de Oliveira, Valéria

    2013-01-01

    Quercetin and rutin are well-know flavonoids. In spite of this, the comprehension of their metabolism is still incomplete. In this work, the cytotoxic activity of quercetin and rutin and its metabolites produced by metabolism of filamentous fungi was investigated. Flavonoids metabolism was monitored by HPLC and LC-MS. Both flavonoids were extensively metabolized. Quercetin was converted into metabolite methylquercetin (2) and quercetin glucuronide (3) and rutin into metabolite rutin sulphate (5), methylrutin (6) and rutin glucuronide (7). Cytotoxic effects of rutin, quercetin and its metabolites were measured by MTT tetrazolium reduction test and the trypan blue exclusion assay on HL-60 leukemic cells. The results showed similar concentration-dependent cytotoxic effect for rutin and rutin sulphate (5), while no cytotoxic effect was detected with the metabolites 6 and 7. In relation to the quercetin and its metabolites the results showed that all compounds have a similar concentration-dependent inhibitory effect on HL-60 cells. These findings corroborate the literature, showing that bioconversion is a useful strategy for production of biological active metabolites. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Quercetin-Induced Cell Death in Human Papillary Thyroid Cancer (B-CPAP) Cells

    PubMed Central

    Mutlu Altundağ, Ergül; Kasacı, Tolga; Yılmaz, Ayşe Mine; Karademir, Betül; Koçtürk, Semra; Taga, Yavuz; Yalçın, A. Süha

    2016-01-01

    In this study, we have investigated the antiproliferative effect of quercetin on human papillary thyroid cancer cells and determined the apoptotic mechanisms underlying its actions. We have used different concentrations of quercetin to induce apoptosis and measured cell viability. Apoptosis and cell cycle analysis was determined by flow cytometry using Annexin V and propidium iodide. Finally, we have measured changes in caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP) protein expression levels as hallmarks of apoptosis and Hsp90 protein expression level as a marker of proteasome activity in treated and control cells. Quercetin treatment of human papillary thyroid cancer cells resulted in decreased cell proliferation and increased rate of apoptosis by caspase activation. Furthermore, it was demonstrated that quercetin induces cancer cell apoptosis by downregulating the levels of Hsp90. In conclusion, we have shown that quercetin induces downregulation of Hsp90 expression that may be involved in the decrease of chymotrypsin-like proteasome activity which, in order, induces inhibition of growth and causes cell death in thyroid cancer cells. Thus, quercetin appears to be a promising candidate drug for Hsp90 downregulation and apoptosis of thyroid cancer cells. PMID:27057371

  13. Activities of muscadine grape skin and quercetin against Helicobacter pylori infection in mice.

    PubMed

    Brown, J C; Wang, J; Kasman, L; Jiang, X; Haley-Zitlin, V

    2011-01-01

    To explore the preventative potential of muscadine grape skin (MGS) and the single flavonoid, quercetin, as an alternative means for ameliorating Helicobacter pylori infection and/or the H. pylori-induced inflammatory response in mice. The antimicrobial and anti-inflammatory properties of MGS and quercetin, a major phenolic constituent, were evaluated against H. pylori in vitro and in vivo. The antimicrobial activity of quercetin was evaluated against 11 H. pylori strains in vitro with inhibition of all strains at 128-64 μg ml(-1) . In vivo studies showed a moderate reduction in H. pylori counts following treatment with 5 and 10% MGS or quercetin (25 mg kg(-1) body weight) in addition to significantly reduced inflammatory cytokines (TNF-α, IL-1β and IFN-γ) when compared with untreated mice. MGS and quercetin did not significantly reduce H. pylori growth in a mouse model. However, these products were effective in regulating the inflammatory response to H. pylori infection. Our results suggest that H. pylori infection may be reduced or prevented via the consumption of fruits rich in certain phenolic compounds (e.g. quercetin) such as muscadine grapes. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

  14. Effect of quercetin against mixture of four organophosphate pesticides induced nephrotoxicity in rats.

    PubMed

    Li, Sifan; Cao, Can; Shi, Haidan; Yang, Shuang; Qi, Lei; Zhao, Xiujuan; Sun, Changhao

    2016-01-01

    1. It has been demonstrated that the ingestion of foods containing quercetin protects against the toxicity of single pesticides. The aim of this study is to make a comprehensive elaboration about the protective effect of quercetin against multi-organophosphorous pesticides induced nephrotoxicity by measuring indices in rat kidney, urine and serum. Rats were divided into six groups (n = 10/group): control, two different doses of quercetin, pesticide mixture (PM), and different doses of quercetin plus PM-treated groups. 2. The following parameters were significantly changed in PM-treated groups compared with the control (p < 0.01). In kidney, malondialdehyde level raised; catalase, superoxide dismutase activities and glutathione levels were decreased. Comet assay of nephrocytes showed that the proportion of DNA in the tail and tail length increased. In urine, β2-microglobulin, retinol-conjugated protein levels and N-acetyl-β-D-glucosaminidase activity showed increasing response; meanwhile uric acid level was decreased. In serum, creatinine and urea nitrogen levels were increased. However, the anomaly changes of indexes mentioned above in PM-treated group were alleviated when simultaneously administrated with 50 mg/kg body weight/day quercetin (p < 0.05). 3. From the present findings, it can be evaluated that quercetin may protect against adverse effects resulted from multi-organophosphorous pesticides with significant high levels of uptake in man provided.

  15. Highly fluorescent gold nanoclusters based sensor for the detection of quercetin

    NASA Astrophysics Data System (ADS)

    Chen, Zhanguang; Qian, Sihua; Chen, Junhui; Chen, Xi

    2012-12-01

    In this contribution, novel luminescent gold nanoclusters were synthesized by utilizing bovine serum albumin as templates with a simple, rapid, and one-pot procedure. The as-prepared gold nanoclusters were highly dispersed in aqueous solution and emitted an intense red fluorescence under UV light (365 nm). They exhibited strong fluorescence and the maximum excitation and emission wavelengths were 480 and 613.5 nm. In addition, the bovine serum albumin-stabilized gold nanoclusters were successfully utilized as novel fluorescent probes for the detection of quercetin for the first time. It was found that the addition of quercetin induced the strong fluorescence intensity of the gold nanoclusters to decrease. The decrease in fluorescence intensity of the gold nanoclusters caused by quercetin allowed the sensitive detection of quercetin in the range of 8.9 × 10-8-1.8 × 10-4 mol L-1. The detection limit for quercetin is 1.8 × 10-8 mol L-1 at a signal-to-noise ratio of 3. The present sensor for quercetin detection possessed a low detection limit and wide linear range. In addition, the real samples were analyzed with satisfactory results.

  16. Quercetin protects human peripheral blood mononuclear cells from OTA-induced oxidative stress, genotoxicity, and inflammation.

    PubMed

    Periasamy, Ramyaa; Kalal, Iravathy Goud; Krishnaswamy, Rajashree; Viswanadha, VijayaPadma

    2016-07-01

    Ochratoxin A (OTA) is one of the most abundant food-contaminating mycotoxins world wide, and is detrimental to human and animal health. This study evaluated the protective effect of quercetin against OTA-induced cytotoxicity, genotoxicity, and inflammatory response in lymphocytes. Cytotoxicity determined by MTT assay revealed IC20 value of OTA to be 20 µM, which was restored to near control values by pretreatment with quercetin. Oxidative stress parameters such as antioxidant enzymes, LPO and PCC levels indicated that quercetin exerted a protective effect on OTA-induced oxidative stress. Quercetin exerted an antigenotoxic effect on OTA-induced genotoxicity, by significantly reducing the number of structural aberrations in chromosomes and comet parameters like, % olive tail moment from 2.76 ± 0.02 to 0.56 ± 0.02 and % tail DNA from 56.23 ± 2.56 to 12.36 ± 0.56 as determined by comet assay. OTA-induced NO, TNF-α, IL-6, and IL-8 were significantly reduced in the quercetin pretreated samples indicating its anti-inflammatory role. Our results demonstrate for the first time that quercetin exerts a cytoprotective effect against OTA-induced oxidative stress, genotoxicity, and inflammation in lymphocytes. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 855-865, 2016.

  17. Quercetin changes purinergic enzyme activities and oxidative profile in platelets of rats with hypothyroidism.

    PubMed

    Baldissarelli, Jucimara; Santi, Adriana; Schmatz, Roberta; Zanini, Daniela; Cardoso, Andréia M; Abadalla, Fátima H; Thomé, Gustavo R; Murussi, Camila; Polachini, Carla R N; Delenogare, Diéssica P; Loro, Vania L; Morsch, Vera M; Schetinger, Maria R C

    2016-12-01

    Diseases related to thyroid hormones have been extensively studied because affect a large number of individuals, and these hormones participate in the regulation of the whole organism homeostasis. However, little is known about the involvement of purinergic signaling related to oxidative stress in hypothyroidism and possible therapeutic adjuncts for treatment of this disorder. Thus, the present study investigates the effects of quercetin on NTPDase, 5'-nucleotidase and adenosine deaminase activities, platelet aggregation and oxidative profile in platelets of rats with methimazole (MMI)-induced hypothyroidism. Methimazole at a concentration of 20mg/100mL was administered for 90days. From the second month the animals received quercetin 10 or 25mg/kg for 60days. Results showed that: Ecto-5'-nucleotidase activity decreased in methimazole/water group and the treatment with quercetin 25mg/kg decreased NTPDase, 5'-nucleotidase and adenosine deaminase activities. Moreover, platelet aggregation increased in methimazole/water group. Lipid peroxidation increased while superoxide dismutase and catalase activities decreased, but, interestingly, the treatment with quercetin reversed these changes. These results demonstrated that quercetin modulates adenine nucleotide hydrolysis decreasing the ADP formation and adenosine deamination. At the same time quercetin improves the oxidative profile, as well as reduces platelet aggregation, which together with the modulation in the nucleotides levels can contribute to the prevention of platelet disorders.

  18. Melibiose, a Nondigestible Disaccharide, Promotes Absorption of Quercetin Glycosides in Rat Small Intestine.

    PubMed

    Tanaka, Seiya; Shinoki, Aki; Hara, Hiroshi

    2016-12-14

    We demonstrated that melibiose, a nondigestible disaccharide composed of galactose and glucose with α-1,6 glycoside linkage, promotes the absorption of water-soluble quercetin glycosides in ligated small intestinal loop of anesthetized rats. Water-soluble quercetin glycoside, a quercetin-3-O-glucoside mixture (Q3GM), includes quercetin-3-O-glucoside (Q3G, 31.9%), mono (21.2%) and di (17.1%), glucose adducts with α-1,4 linkages. After instillation of Q3GM into the intestinal loop with or without melibiose, the plasma concentration of quercetin derivatives in the portal blood was considerably higher in the melibiose group at 60 min. Furthermore, we evaluated the hydrolytic rate of Q3G by the mucosal homogenate of the small intestine with six different disaccharides. Melibiose and isomaltose, which have α-1,6 glycoside linkage, were found to promote Q3G hydrolysis to aglycone. These results suggest that melibiose promotes quercetin glycoside absorption in rats by increasing glycoside hydrolysis in the intestinal lumen and that α-1,6 linkage is involved in this process.

  19. Apoptotic effect of quercetin on HT-29 colon cancer cells via the AMPK signaling pathway.

    PubMed

    Kim, Hyeong-Jin; Kim, Sang-Ki; Kim, Byeong-Soo; Lee, Seung-Ho; Park, Young-Seok; Park, Byung-Kwon; Kim, So-Jung; Kim, Jin; Choi, Changsun; Kim, Jong-Suk; Cho, Sung-Dae; Jung, Ji-Won; Roh, Kyong-Hwan; Kang, Kyung-Sun; Jung, Ji-Youn

    2010-08-11

    Activation of AMP-activated protein kinase (AMPK), a physiological cellular energy sensor, strongly suppresses cell proliferation in both nonmalignant and tumor cells. This study demonstrates the mechanism of quercetin-induced apoptosis in HT-29 colon cancer cells. Treatment of cells with quercetin significantly decreased cell viability in a dose-dependent manner. Notably, quercetin increased cell cycle arrest in the G1 phase and up-regulated apoptosis-related proteins, such as AMPK, p53, and p21, within 48 h. Furthermore, in vivo experiments showed that quercetin treatment resulted in a significant reduction in tumor volume over 6 weeks, and apoptosis-related protein induction by quercetin was significantly higher in the 100 mg/kg treated group compared to the control group. All of these results indicate that quercetin induces apoptosis via AMPK activation and p53-dependent apoptotic cell death in HT-29 colon cancer cells and that it may be a potential chemopreventive or therapeutic agent against HT-29 colon cancer.

  20. [Quercetin inhibits growth and induces apoptosis of human gastric carcinoma cells].

    PubMed

    Wang, Hai-yan; Guo, Liang-miao; Chen, Yong; Zhao, Xue-hua; Cheng, Cai-lian; Wu, Mian-yun; He, Li-ya

    2006-09-01

    To study the effect of quercetin on the growth and apoptosis of human gastric carcinoma cell line MGC-803. The measurement of inhibitory rate and apoptotic index(AI) of quercetin were done by MTT assay and TUNEL assay. The positive expression rate of P53, C-myc and P16 were detected by immunocytochemical staining. Quercetin at concentrations ranging from 40 mumol/L to 100 mumol/L significantly inhibited the proliferation of MGC-803 cells in a dose- and time-dependent manner (P<0.01). TUNEL assay indicated that the number of apoptotic cells in quercetin-treated group was greater than that in the control group (P<0.01). Expression of P53 and C-myc protein decreased following quercetin induction in a dose-dependent manner, whereas P16 expression increased significantly compared with that of the control group (P<0.01). Quercetin can inhibit the growth and induce apoptosis of MGC-803 cells in a dose- and time-dependent manner. Its mechanisms may be relevant to the down-regulation of P53 and C-myc protein expression as well as up-regulation of P16 expression.

  1. Protective effects of quercetin on UVB irradiation‑induced cytotoxicity through ROS clearance in keratinocyte cells.

    PubMed

    Zhu, Xianbing; Li, Ning; Wang, Yiling; Ding, Li; Chen, Houjie; Yu, Yehui; Shi, Xiaojun

    2017-01-01

    Human skin is the body's largest organ that protects against diverse environmental injuries. However, ultraviolet (UV) radiation, which induces a transient increase in the intracellular level of reactive oxygen species (ROS) and leads to a variety of injuries and various skin diseases, has deleterious effects on living organisms. Quercetin is a naturally occurring compound with strong antioxidant action and can successfully scavenge free radicals. In the present study, we investigated the effects and the mechanism of quercetin on UVB‑induced cytotoxicity in keratinocyte (HaCaT) cells. The results of this study showed that quercetin (20 μM) significantly blocked UVB irradiation (15 mJ/cm2)‑induced intracellular ROS generation. In addition, the ROS clearing ability of quercetin prevented cell membrane and mitochondria from ROS attack and inhibited cell membrane fluidity decrease and mitochondrial membrane depolarization. Moreover, the outflow of cytochrome c and apoptosis were markedly inhibited. These results suggest that the protective effect of quercetin against UVB irradiation‑induced toxicity is mainly mediated by the ROS scavenging ability. Thus, quercetin is a potential agent against UVB irradiation‑induced skin damage.

  2. Quercetin-induced apoptotic cascade in cancer cells: antioxidant versus estrogen receptor alpha-dependent mechanisms.

    PubMed

    Galluzzo, Paola; Martini, Chiara; Bulzomi, Pamela; Leone, Stefano; Bolli, Alessandro; Pallottini, Valentina; Marino, Maria

    2009-06-01

    The flavonol quercetin, especially abundant in apple, wine, and onions, is reported to have anti-proliferative effects in many cancer cell lines. Antioxidant or pro-oxidant activities and kinase inhibition have been proposed as molecular mechanisms for these effects. In addition, an estrogenic activity has been observed but, at the present, it is poorly understood whether this latter activity plays a role in the quercetin-induced anti-proliferative effects. Here, we studied the molecular mechanisms of quercetin committed to the generation of an apoptotic cascade in cancer cells devoid or containing transfected estrogen receptor alpha (ERalpha; i.e., human cervix epitheloid carcinoma HeLa cells). Although none of tested quercetin concentrations increase reactive oxygen species (ROS) generation in HeLa cells, quercetin stimulation prevents the H(2)O(2)-induced ROS production both in the presence and in the absence of ERalpha. However, this flavonoid induces the activation of p38/MAPK, leading to the pro-apoptotic caspase-3 activation and to the poly(ADP-ribose) polymerase cleavage only in the presence of ERalpha. Notably, no down-regulation of survival kinases (i.e., AKT and ERK) was reported. Taken together, these findings suggest that quercetin results in HeLa cell death through an ERalpha-dependent mechanism involving caspase- and p38 kinase activation. These findings indicate new potential chemopreventive actions of flavonoids on cancer growth.

  3. Quercetin inhibits advanced glycation end product formation by trapping methylglyoxal and glyoxal.

    PubMed

    Li, Xiaoming; Zheng, Tiesong; Sang, Shengmin; Lv, Lishuang

    2014-12-17

    Methylglyoxal (MGO) and glyoxal (GO) not only are endogenous metabolites but also exist in exogenous resources, such as foods, beverages, urban atmosphere, and cigarette smoke. They have been identified as reactive dicarbonyl precursors of advanced glycation end products (AGEs), which have been associated with diabetes-related long-term complications. In this study, quercetin, a natural flavonol found in fruits, vegetables, leaves, and grains, could effectively inhibit the formation of AGEs in a dose-dependent manner via trapping reactive dicarbonyl compounds. More than 50.5% of GO and 80.1% of MGO were trapped at the same time by quercetin within 1 h under physiological conditions. Quercetin and MGO (or GO) were combined at different ratios, and the products generated from this reaction were analyzed with LC-MS. Both mono-MGO and di-MGO adducts of quercetin were detected in this assay using LC-MS, but only tiny amounts of mono-GO adducts of quercetin were found. Additionally, di-MGO adducts were observed as the dominant product with prolonged incubation time. In the bovine serum albumin (BSA)-MGO/GO system, quercetin traps MGO and GO directly and then significantly inhibits the formation of AGEs.

  4. Quercetin and related polyphenols: new insights and implications for their bioactivity and bioavailability.

    PubMed

    Kawabata, Kyuichi; Mukai, Rie; Ishisaka, Akari

    2015-05-01

    The physiological functions and bioavailability of flavonoids have been widely investigated since their bioactivities were identified about 80 years ago. Quercetin is a typical flavonoid ubiquitously contained in vegetables and fruits with several biological effects demonstrated in vitro and in vivo including antioxidative, anti-inflammatory, anticancer, and antidiabetic activities. After the ingestion of vegetables and fruits, quercetin glycosides are metabolized, absorbed, and circulated as types of conjugates in the blood. Thereafter, quercetin-3-O-β-D-glucuronide (Q3GA), a major metabolite of quercetin, is distributed throughout the body where it may exert beneficial functions in target tissues. Hydrophilic Q3GA has been found to be deconjugated into hydrophobic quercetin aglycone at injured sites which, in turn, may improve the pathological conditions. This review presents updated information on the biological aspects and mechanisms of action of quercetin and its related polyphenols. In particular, new insights into their beneficial health effects on the brain, blood vessels, muscle, and intestine will be discussed.

  5. Ultrastructural changes during lung carcinogenesis-modulation by curcumin and quercetin

    PubMed Central

    Wang, Xin; Wang, Lei; Zhang, Hao; Li, Ke; You, Jiqin

    2016-01-01

    The aim of the present study was to examine the effectiveness of curcumin and quercetin in modulating ultrastructural changes during lung carcinogenesis. A total of 24 male laka mice were divided into the normal control, benzo[a]pyrene (BP)-treated, BP+curcumin-treated, BP+quercetin- treated, and BP+curcumin+quercetin-treated groups (n=6 per group). Lung carcinogenesis was induced by a single intraperitoneal injection of BP [100 mg/kg of body weight (b.wt.)]. Curcumin was supplemented to mice at a dose level of 60 mg/kg of b.wt. in drinking water and quercetin was given at a dose level of 40 mg/kg of b.wt. in drinking water. The ultrastructure of BP-treated mice revealed disruptions in cellular integrity together with nuclear deformation and premature mitochondrial aging. Notably, supplementation with phytochemicals individually resulted in improvement of the ultra-histoarchitecture of BP-treated mice although the improvement was much greater with combined supplementation of phytochemicals. Furthermore, BP treatment revealed alterations in lung histoarchitecture, which, however, were improved appreciably following combined supplementation with curcumin and quercetin. The results of the present study show that, combined supplementation with curcumin and quercetin effectively preserved the histoarchitecture as well as ultra-histoarchitecture during BP-induced lung carcinogenesis in mice. PMID:28101199

  6. Differential effect of quercetin on cisplatin-induced toxicity in kidney and tumor tissues.

    PubMed

    Sánchez-González, Penélope D; López-Hernández, Francisco J; Dueñas, Montserrat; Prieto, Marta; Sánchez-López, Elsa; Thomale, Jürgen; Ruiz-Ortega, Marta; López-Novoa, José M; Morales, Ana I

    2017-09-01

    Strategies to minimize the nephrotoxicity of platinated antineoplastics without affecting its antitumour efficacy are strongly necessary to improve the pharmacotoxicological profile of these drugs. The natural flavonoid quercetin has been shown to afford nephroprotection without affecting cisplatin antitumour effect. The purpose of the present study has been to assess the differential mechanisms of action of cisplatin and quercetin on kidney and tumour tissues that could explain these effects. Wistar rats bearing subcutaneous tumours were treated with cisplatin and quercetin (and the appropriate controls). Tumour size and renal function evolution was monitored during 6 days. Platinum and quercetin content were also determined in both tissues. All the parameters studied, including blood supply, inflammation, apoptosis, critical MAPK signaling and oxidative stress in the cisplatin-treated animals are almost normalized by quercetin in the kidneys, but unaffected in the tumours. Our results suggest that in a cancer model in vivo, the protection exerted by quercetin on cisplatin nephrotoxicity is related to its antioxidant, vascular, anti-inflammatory and antiapoptotic effects, but these properties do not affect the mechanisms responsible for the antitumour effect of cisplatin. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Pharmacology in health food: metabolism of quercetin in vivo and its protective effect against arteriosclerosis.

    PubMed

    Ishizawa, Keisuke; Yoshizumi, Masanori; Kawai, Yoshichika; Terao, Junji; Kihira, Yoshitaka; Ikeda, Yasumasa; Tomita, Shuhei; Minakuchi, Kazuo; Tsuchiya, Koichiro; Tamaki, Toshiaki

    2011-01-01

    Quercetin, a member of the bioflavonoids family, has been proposed to have anti-atherogenic, anti-inflammatory, and anti-hypertensive properties leading to the beneficial effects against cardiovascular diseases. It was recently demonstrated that quercetin 3-O-β-D-glucuronide (Q3GA) is one of the major quercetin conjugates in human plasma, in which the aglycone could not be detected. Although most of the in vitro pharmacological studies have been carried out using only the quercetin aglycone form, experiments using Q3GA would be important to discover the preventive mechanisms of cardiovascular diseases by quercetin in vivo. Therefore we examined the effects of the chemically synthesized Q3GA, as an in vivo form, on vascular smooth muscle cell (VSMC) disorders related to the progression of arteriosclerosis. Platelet-derived growth factor-induced cell migration and proliferation were inhibited by Q3GA in VSMCs. Q3GA attenuated angiotensin II-induced VSMC hypertrophy via its inhibitory effect on JNK and the AP-1 signaling pathway. Q3GA scavenged 1,1-diphenyl-2-picrylhydrazyl radical measured by the electron paramagnetic resonance method. In addition, immunohistochemical studies with monoclonal antibody 14A2 targeting the Q3GA demonstrated that the positive staining specifically accumulates in human atherosclerotic lesions, but not in the normal aorta. These findings suggest Q3GA would be an active metabolite of quercetin in plasma and may have preventative effects on arteriosclerosis relevant to VSMC disorders.

  8. Quercetin protects hamster spermatogenic cells from oxidative damage induced by diethylstilboestrol.

    PubMed

    Li, G; Ma, Aituan; Shi, W; Zhong, Xiuhui

    2010-10-01

    Quercetin has been reported to be an efficient antioxidant which protects chicken spermatogonial cells from oxidative damage through increasing intracellular antioxidants and decreasing lipid peroxidation. Exposure to diethylstilboestrol (DES) could cause reproductive damage in males, which is associated with oxidative stress. This study was conducted to investigate the protective effects of quercetin on DES-induced oxidative damage in cultured hamster spermatogenic cells. The cells were treated with different concentrations of DES, and their growth status was observed under inverted microscope. The viability of spermatogenic cells was detected by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT). The contents of superoxide dismutase (SOD) in supernatants and glutathione peroxidase (GSH-Px) in cells were detected with spectrophotography. The results showed that quercetin significantly inhibited the DES-induced damage on spermatogenic cells, with the exception of the low-dose group in which no significant difference was observed. The cell survival rate increased significantly in the middle- and high-dose groups. The contents of SOD and GSH-Px were significantly elevated after medication with quercetin (P < 0.01). It can be concluded that quercetin protects spermatogenic cells against DES-induced oxidative damage through increasing intracellular antioxidants and decreasing lipid peroxidation. Quercetin plays a very important role in ameliorating reproductive toxicity induced by environmental oestrogens.

  9. Quercetin Attenuates Warfarin-induced Vascular Calcification in Vitro Independently from Matrix Gla Protein*

    PubMed Central

    Beazley, Kelly E.; Eghtesad, Saman; Nurminskaya, Maria V.

    2013-01-01

    Warfarin can stimulate vascular calcification in vitro via activation of β-catenin signaling and/or inhibition of matrix Gla protein (MGP) carboxylation. Calcification was induced in vascular smooth muscle cells (VSMCs) with therapeutic levels of warfarin in normal calcium and clinically acceptable phosphate levels. Although TGF/BMP and PKA pathways are activated in calcifying VSMCs, pharmacologic analysis reveals that their activation is not contributory. However, β-catenin activity is important because inhibition of β-catenin with shRNA or bioflavonoid quercetin prevents calcification in primary human VSMCs, rodent aortic rings, and rat A10 VSMC line. In the presence of quercetin, reactivation of β-catenin using the glycogen synthase kinase-3β (GSK-3β) inhibitor LiCl restores calcium accumulation, confirming that quercetin mechanism of action hinges on inhibition of the β-catenin pathway. Calcification in VSMCs induced by 10 μm warfarin does not associate with reduced levels of carboxylated MGP, and inhibitory effects of quercetin do not involve induction of MGP carboxylation. Further, down-regulation of MGP by shRNA does not alter the effect of quercetin. These results suggest a new β-catenin-targeting strategy to prevent vascular calcification induced by warfarin and identify quercetin as a potential therapeutic in this pathology. PMID:23223575

  10. Onion extract and quercetin induce matrix metalloproteinase-1 in vitro and in vivo.

    PubMed

    Cho, Jae-We; Cho, Sun-Young; Lee, Seong-Ryong; Lee, Kyu-Suk

    2010-03-01

    A scar is usually developed by an imbalance of collagen synthesis and degradation. It is believed that the flavonoids (quercetin and kaempferol) in onion extract play a role in reducing scar formation through inhibition of fibroblast activities. Even though several commercial products are composed of onion extract, the precise molecular mechanisms of onion extract in reduction of scar formation in skin are still largely unknown. In this study we investigated the effect both of onion extract and quercetin on the proliferation of fibroblasts, expression of type I collagen and matrix metalloproteinase-1 (MMP-1). Our data show that proliferation rates of fibroblasts were decreased in a dose-dependent manner of the onion extract and quercetin. The expression of type I collagen was not markedly changed by the onion extract and quercetin. Interestingly, the expression of MMP-1 was markedly increased by both onion extract and quercetin in vitro and in vivo. Thus, our data indicate that onion extract and quercetin play a role in the anti-scar effect in skin through up-regulation of MMP-1 expression, implying this agent is a promising material for reducing scar formation.

  11. Ultrastructural changes during lung carcinogenesis-modulation by curcumin and quercetin.

    PubMed

    Wang, Xin; Wang, Lei; Zhang, Hao; Li, Ke; You, Jiqin

    2016-12-01

    The aim of the present study was to examine the effectiveness of curcumin and quercetin in modulating ultrastructural changes during lung carcinogenesis. A total of 24 male laka mice were divided into the normal control, benzo[a]pyrene (BP)-treated, BP+curcumin-treated, BP+quercetin- treated, and BP+curcumin+quercetin-treated groups (n=6 per group). Lung carcinogenesis was induced by a single intraperitoneal injection of BP [100 mg/kg of body weight (b.wt.)]. Curcumin was supplemented to mice at a dose level of 60 mg/kg of b.wt. in drinking water and quercetin was given at a dose level of 40 mg/kg of b.wt. in drinking water. The ultrastructure of BP-treated mice revealed disruptions in cellular integrity together with nuclear deformation and premature mitochondrial aging. Notably, supplementation with phytochemicals individually resulted in improvement of the ultra-histoarchitecture of BP-treated mice although the improvement was much greater with combined supplementation of phytochemicals. Furthermore, BP treatment revealed alterations in lung histoarchitecture, which, however, were improved appreciably following combined supplementation with curcumin and quercetin. The results of the present study show that, combined supplementation with curcumin and quercetin effectively preserved the histoarchitecture as well as ultra-histoarchitecture during BP-induced lung carcinogenesis in mice.

  12. Protective Effects of Quercetin against Dimethoate-Induced Cytotoxicity and Genotoxicity in Allium sativum Test

    PubMed Central

    Ahmad, Waseem; Shaikh, Sibhghatulla; Nazam, Nazia; Lone, Mohammad Iqbal

    2014-01-01

    The present investigation was directed to study the possible protective activity of quercetin—a natural antioxidant against dimethoate-induced cyto- and genotoxicity in meristematic cells of Allium sativum. So far there is no report on the biological properties of quercetin in plant test systems. Chromosome breaks, multipolar anaphase, stick chromosome, and mitotic activity were undertaken in the current study as markers of cyto- and genotoxicity. Untreated control, quercetin controls (@ 5, 10 and 20 μg/mL for 3 h), and dimethoate exposed groups (@ 100 and 200 μg/mL for 3 h) were maintained. For protection against cytogenotoxicity, the root tip cells treated with dimethoate at 100 and 200 μg/mL for 3 h and quercetin treatment at 5, 10, and 20 μg/mL for 16 h, prior to dimethoate treatment, were undertaken. Quercetin was found to be neither cytotoxic nor genotoxic in Allium sativum control at these doses. A significant increase (P < 0.05) in chromosomal aberrations was noted in dimethoate treated Allium. Pretreatment of Allium sativum with quercetin significantly (P < 0.05) reduced dimethoate-induced genotoxicity and cytotoxicity in meristematic cells, and these effects were dose dependent. In conclusion, quercetin has a protective role in the abatement of dimethoate-induced cyto- and genotoxicity in the meristematic cells of Allium sativum that resides, at least in part, on its antioxidant effects. PMID:27379342

  13. Transformation of rutin to antiproliferative quercetin-3-glucoside by Aspergillus niger.

    PubMed

    You, Hyun Ju; Ahn, Hyung Jin; Ji, Geun Eog

    2010-10-27

    The flavonol quercetin in plants and foods occurs predominantly in the form of glycoside whose sugar moiety affects the bioavailability and the mechanism of its biological activities. The antiproliferative activities of quercetin derivatives such as quercetin aglycone, quercetin-3-β-D-glucoside (Q3G), and rutin were compared using six different cancer cell lines including colon, breast, hepatocellular, and lung cancer. The IC50 value of Q3G ranged between 15 and 25 μM in HT-29, HCT 116, MCF-7, HepG2, and A549 cells. In these five cell lines, Q3G showed the most potent growth inhibition, whereas rutin showed the least potency. Transformation of rutin to Q3G was conducted by controlling α-L-rhamnosidase and β-D-glucosidase activities from crude enzyme extract of Aspergillus niger. Carbon sources during culture and transformation conditions such as pH, temperature, and heat-stability were optimized. After 4 h biotransformation, 99% of rutin was transformed to Q3G and no quercetin was detected. This study presented an efficient biotransformation for the conversion of rutin to Q3G which was newly shown to have more potent antiproliferative effect than quercetin and rutin.

  14. Effects of quercetin on proliferation and migration of human glioblastoma U251 cells.

    PubMed

    Liu, Yue; Tang, Zhen-Gang; Lin, Yi; Qu, Xin-Guo; Lv, Wei; Wang, Guo-Bin; Li, Cai-Li

    2017-08-01

    Quercetin is a flavonoid that has been shown to have anti-oxidation, anti-inflammation, anti-allergic, anti-viral, and anti-cancer activities. Here, we examined the effects of quercetin on cell viability, cell cycle progression, and migration in U251 cells, a human glioblastoma cell line. We found that quercetin inhibited cell proliferation after treating cells for 24 (IC50 of 113.65μg/ml) or 48h (IC50 of 48.61μg/ml). Quercetin treatment also induced apoptosis via deregulating the expression of apoptotic genes, including Bax and Bcl-2, and arrested cell cycle at G2/M phases. We further found that quercetin impaired cell migration and invasion via downregulating the expression of matrix metallopeptidases MMP9 and MMP2. Our results provide evidences that quercetin has inhibitory effects on glioblastoma cell proliferation and invasion, and suggest a potential clinical application for glioblastoma. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  15. Low concentration of quercetin antagonizes the invasion and angiogenesis of human glioblastoma U251 cells.

    PubMed

    Liu, Yue; Tang, Zhen-Gang; Yang, Jian-Quan; Zhou, Yi; Meng, Ling-Hu; Wang, Heng; Li, Cai-Li

    2017-01-01

    Glioblastoma is the most aggressive type of brain tumor with a very poor prognosis. Therefore, it is always of great importance to explore and develop new potential treatment for glioblastoma. Quercetin, a flavonoid present in a variety of human foods, has been shown to inhibit various tumor cell proliferation. In this study, we found that treating human glioblastoma U251 cells with 10 μg/mL quercetin for 24 hours, a concentration that was far below the IC50 (113.65 μg/mL) and at which quercetin failed to inhibit cell proliferation, inhibited cell migration (30%) and cell invasion as examined by wound scratch assay and transwell assay, respectively. We further showed that 10 μg/mL quercetin inhibited cell migration and tube formation of human umbilical vein endothelial cells induced by the conditioned medium derived from U251 cell culture. The inhibitory effect of quercetin on migration and angiogenesis is possibly mediated through the downregulation of protein levels of VEGFA, MMP9, and MMP2 as detected by Western blot. Our findings demonstrated that low concentration of quercetin antagonized glioblastoma cell invasion and angiogenesis in vitro.

  16. Quercetin suppresses cellular migration and invasion in human head and neck squamous cell carcinoma (HNSCC).

    PubMed

    Chan, Chien-Yi; Lien, Chia-Hsien; Lee, Ming-Fen; Huang, Chun-Yin

    2016-06-01

    Head and neck squamous cell carcinoma (HNSCC) with aberrant epidermal growth factor receptor (EGFR) signaling is often associated with a poor prognosis and a low survival rate. Hence, efficient inhibition of the EGFR signaling-mediated malignancy would improve survival rate. In a previous study, we demonstrated that quercetin appears to be a potent anti-tumorigenic agent through its inhibition of the EGFR/Akt pathway in oral cancer, but its anti-metastatic potential in HNSCC remains unclear [1]. Here, we have hypothesized that quercetin might be effective in metastatic inhibition in EGFR-overexpressing HNSCC cells. Quercetin treatment with 10 μM (half concentration of IC50) suppressed cell migration and invasion in EGFR-overexpressing HSC-3 and FaDu HNSCC cells. Quercetin also inhibited the colony growth of HSC-3 cells embedded in a Matrigel matrix. Among matrix metalloproteinases (MMPs), the secreted gelatinases MMP-2 and MMP-9 are responsible for the degradation of gelatin in the extracellular matrix and type IV collagen in the basement membrane; and this degradation event is crucial for the migration from the origin and the invasion into the bone in HNSCC. Quercetin (10 μM) treatment also suppressed the expression and proteolytic activity of MMP-2 and MMP-9. Taken together, our data indicate that quercetin is an effective anti-cancer agent against MMP-2- and MMP-9-mediated metastasis in EGFR-overexpressing HNSCC.

  17. Induction of apoptosis by phenylisocyanate derivative of quercetin: involvement of heat shock protein.

    PubMed

    Ye, Bin; Yang, Jin-Liang; Chen, Li-Juan; Wu, Xian-Xue; Yang, Han-Shuo; Zhao, Ju-Mei; Yuan, Zhi-Ping; Li, Jiong; Wen, Yan-Jun; Mao, Yong-Qiu; Lei, Song; Kan, Bing; Fan, Lin-Yu; Yao, Wen-Xiu; Wang, Rui; Wang, Guo-Qing; Du, Xiao-Bo; Liu, Huan-Yi; Wu, Hong-Bing; Xu, Jian-Rong; Li, Hong-Xia; Zhang, Wei; Zhao, Xia; Wei, Yu-Quan; Cheng, Li

    2007-11-01

    Quercetin, a widely distributed bioflavonoid, inhibits the growth of various tumor cells. The present study was designed to investigate whether a novel quercetin derivative [phenylisocyanate of quercetin (PHICNQ)] exerts antitumor activity against K562 and CT26 tumor cell lines by inducing apoptosis, and to examine the possible mechanism in the phenomenon. The cell proliferation assay of K562 and CT26 tumor cells was determined by the trypan blue dye exclusion test. Apoptosis of PHICNQ-treated cells was determined by morphological analysis, agarose gel DNA electrophoresis and quantitated by flow cytometry after staining with propidium iodide. Cell cycle was evaluated by flow cytometry. The expression of heat shock protein 70 was checked by Western blot analysis. Our results showed that PHICNQ inhibited the proliferation of K562 and CT26 cells in a dose-dependent and time-dependent manner. PHICNQ was 308- and 73-fold more active on CT26 and K562 cells than quercetin, respectively. In addition to this cytostatic effect, treatment of K562 and CT26 tumor cells with PHICNQ induced apoptosis. PHICNQ treatment downregulated the expression of heat shock protein 70 more dramatically than quercetin treatment. These results suggest that PHICNQ is a more powerful antiproliferative derivative than quercetin, with cytostatic and apoptotic effects on K562 and CT26 tumor cells. PHICNQ may trigger apoptosis in tumor cells through inhibition of heat shock protein 70 synthesis and expression.

  18. Effect of the oral administration of nanoencapsulated quercetin on a mouse model of Alzheimer's disease.

    PubMed

    Moreno, Lina Clara Gayoso E Ibiapina; Puerta, Elena; Suárez-Santiago, José Eduardo; Santos-Magalhães, Nereide Stela; Ramirez, Maria J; Irache, Juan M

    2017-01-30

    Quercetin has been identified as a promising compound with a neuroprotective potential against age-related neurodegenerative diseases such as Alzheimer's disease (AD). Nevertheless, the clinical application of quercetin is hampered by its low oral bioavailability. The aim of this work was to evaluate the capability of nanoencapsulated quercetin in zein nanoparticles (NPQ), that significantly improves the oral absorption and bioavailability of the flavonoid, as potential oral treatment for AD. For this purpose, SAMP8 mice were orally treated for two months with either NPQ (25mg/kg every 48h) or a solution of quercetin (Q; 25mg/kg daily). NPQ displayed a size of 260nm and a payload of about 70μg/mg. For Q, no significant effects were observed in animals. On the contrary, the oral administration of NPQ improved the cognition and memory impairments characteristics of SAMP8 mice. These observations appeared to be related with a decreased expression of the hippocampal astrocyte marker GFAP. Furthermore, significant levels of quercetin were quantified in the brain of mice treated with nanoparticles. These findings highlight the potential of zein nanoparticles to promote the oral absorption of quercetin as well as the therapeutic potential of this flavonoid in AD pathogenesis.

  19. Oxidative Stability in Oil-in-Water Emulsions with Quercetin or Rutin Under Iron Catalysis or Riboflavin Photosensitization.

    PubMed

    Yi, BoRa; Ka, HaeJung; Kwon, YongJun; Choi, HyungSeok; Kim, Sunghwa; Kim, Jisu; Kim, Mi-Ja; Lee, JaeHwan

    2017-04-01

    The effects of quercetin and rutin on the oxidative stability of oil-in-water (O/W) emulsions were tested under riboflavin (RF) photosensitization in the presence or absence of FeCl2 . The degree of oxidation in O/W emulsions was determined by headspace oxygen content, conjugated dienes, and lipid hydroperoxides. Quercetin chelated more metal than did rutin in iron catalyzed O/W emulsions. Generally, 0.1 mM quercetin and rutin was oxidative while 0.5 and 1.0 mM quercetin and rutin was antioxidative in O/W emulsions under RF photosensitization. Depending on the analysis method, the antioxidants had different strengths. The antioxidative or oxidative properties of quercetin and rutin vary in O/W emulsions and depend the quercetin and rutin concentrations and oxidative forces like transition metals, RF photosensitization, or a combination thereof. © 2017 Institute of Food Technologists®.

  20. Protective role of quercetin on PCBs-induced oxidative stress and apoptosis in hippocampus of adult rats.

    PubMed

    Selvakumar, Kandaswamy; Bavithra, Senthamilselvan; Suganthi, Muralidharan; Benson, Chellakan Selvanesan; Elumalai, Perumal; Arunkumar, Ramachandran; Krishnamoorthy, Gunasekaran; Venkataraman, Prabhu; Arunakaran, Jagadeesan

    2012-04-01

    Polychlorinated biphenyls (PCBs) exposure produces neurodegeneration and induces oxidative stress. Neuroprotective role of quercetin, on PCBs induced apoptosis in hippocampus has not yet been studied. The present study is focused to see whether quercetin supplementation precludes against PCBs induced oxidative stress and hippocampal apoptosis. The results have shown that quercetin at 50 mg/kg bwt/30 days has protected oxidative stress in hippocampus of adult male rats. Quercetin, a free radical scavenger decreased the levels of oxidative stress markers in the hippocampus of simultaneous PCB+quercetin treated rats. The pro-apoptotic and anti-apoptotic molecules such as Bad, Bid, Bax and Bcl2 were altered in the hippocampus of experimental animals. PCBs increased the DNA damage and induced neurodegeneration were assessed by histological studies. PCB induced ROS may be linked to increased hippocampal neuronal apoptosis. Quercetin supplementation decreased the neuronal damage and scavenged the free radicals induced by PCBs and protects PCBs induced apoptosis and oxidative stress.