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Jang, Ae-Ra, Jun-Sang Ham, Dong-Wook Kim, Hyun-Seok Chae, Dong-Wook Kim, Sang-Ho Kim, Kuk-Hwan Seol, Mi-Hwa Oh e Dong-Hun Kim. "Effect of Quercetin and Methoxylated Quercetin on Chicken Thigh Meat Quality during Cold Storage". Korean Journal of Poultry Science 38, n.º 4 (31 de dezembro de 2011): 265–73. http://dx.doi.org/10.5536/kjps.2011.38.4.265.
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Preethi, Arul Murugan, e Jayesh R. Bellare. "Concomitant Effect of Quercetin- and Magnesium-Doped Calcium Silicate on the Osteogenic and Antibacterial Activity of Scaffolds for Bone Regeneration". Antibiotics 10, n.º 10 (27 de setembro de 2021): 1170. http://dx.doi.org/10.3390/antibiotics10101170.
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Quercetin is a bioflavonoid which has a broad spectrum of biological activity. Due to its lower chemical stability, it is usually encapsulated, or a metal–quercetin complex is formed to enhance its biological activity at a lower concentration. Here, our novel approach was to form a quercetin complex to magnesium-doped calcium silicate (CMS) ceramics through a coprecipitation technique so as to take advantage of quercetin’s antibacterial activity within the antibacterial and osteogenic potential of the silicate. Due to quercetin’s inherent metal-chelating ability, (Ca+Mg)/Si increased with quercetin concentration. Quercetin in magnesium-doped calcium silicate ceramic showed concentration-dependent pro-oxidant and antioxidant activity in SaOS-2 with respect to quercetin concentration. By optimizing the relative concentration, we were able to achieve 3-fold higher proliferation and 1.6-fold higher total collagen at day 14, and a 1.7-fold higher alkaline phosphatase production at day 7 with respect to polycaprolactone/polyvinylpyrrolidone (PCL/PVP) scaffold. Quercetin is effective against Gram-positive bacteria such as S. aureus. Quercetin is coupled with CMS provided similar effect with lower quercetin concentration than quercetin alone. Quercetin reduced bacterial adhesion, proliferation and biofilm formation. Therefore, quercetin-coupled magnesium-doped calcium silicate not only enhanced osteogenic potential, but also reduced bacterial adhesion and proliferation.
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Shabana, R. C. Jaysree e Rajendran N. "Review on the Bioactivities of Quercetin". International Journal of ChemTech Research 13, n.º 3 (2020): 181–94. http://dx.doi.org/10.20902/ijctr.2019.130315.
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Quercetin, the most active bioflavonoid which is produced as a secondary metabolite by plants, is a polyphenol with a wide spectrum of bioactivities. This bioflavonoid is the ―nature‘s biological response modifier‖ as it interferes with the various allergens and other reactive compounds. Apple, oranges, tomatoes, onions, black tea and green tea are good sources of quercetin and it is also available commercially. After absorption in the small intestine and colon, quercetin conjugates with glucuronic acid and binds to albumin and passes to liver and benefits the body by its various bioactivities. Quercetin‘s antioxidant activity enhances the radical scavenging activity and metal chelation of the ions but the prooxidant activity depends on its high concentration. Further, quercetin interferes with the formation of leukotrienes from arachidonic acid showing its anti-inflammatory effect. A combined effect of quercetin and bromelain effectively suppresses the allergic reactions and the excessive inflammation resulting from bruising and tissue damage. The mutualistic effect of vitamin C and quercetin protects each other from getting oxidized. A direct relationship was also found to exist between quercetin's antiviral activity and enhancement of cyclic adenosine monophosphate (cAMP), which is a second messenger involved in many biological processes. Quercetin helps in down regulation of mutant gene p53 and inhibits the growth of cancerous cells by putting a check at G1 phase. This also controls the surpassing of the normal regulatory growth by the tumor cells and inhibits the production of heat shock proteins and thus showing its anticancer properties. Owing to the potential pharmaceutical properties of quercetin, the bioactivities, principle uses and mechanisms involved in the treatment of various diseases were reviewed in this paper. In addition, safety issues involved in the partake of quercetin by humans have also been discussed.
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Ding, Kaixi, Wei Jiang, Wenling Zhan, Chunping Xiong, Jieling Chen, Yu Wang, Huanan Jia e Ming Lei. "The therapeutic potential of quercetin for cigarette smoking–induced chronic obstructive pulmonary disease: a narrative review". Therapeutic Advances in Respiratory Disease 17 (janeiro de 2023): 175346662311708. http://dx.doi.org/10.1177/17534666231170800.
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Quercetin is a flavonoid with antioxidant and anti-inflammatory properties. Quercetin has potentially beneficial therapeutic effects for several diseases, including cigarette smoking–induced chronic obstructive pulmonary disease (CS-COPD). Many studies have shown that quercetin’s antioxidant and anti-inflammatory properties have positive therapeutic potential for CS-COPD. In addition, quercetin’s immunomodulatory, anti-cellular senescence, mitochondrial autophagy–modulating, and gut microbiota–modulating effects may also have therapeutic value for CS-COPD. However, there appears to be no review of the possible mechanisms of quercetin for treating CS-COPD. Moreover, the combination of quercetin with common therapeutic drugs for CS-COPD needs further refinement. Therefore, in this article, after introducing the definition and metabolism of quercetin, and its safety, we comprehensively presented the pathogenesis of CS-COPD related to oxidative stress, inflammation, immunity, cellular senescence, mitochondrial autophagy, and gut microbiota. We then reviewed quercetin’s anti-CS-COPD effects, performed by influencing these mechanisms. Finally, we explored the possibility of using quercetin with commonly used drugs for treating CS-COPD, providing a basis for future screening of excellent drug combinations for treating CS-COPD. This review has provided meaningful information on quercetin’s mechanisms and clinical use in treating CS-COPD.
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Osterc, G., M. Štefančič, A. Solar e F. Štampar. "Potential involvement of flavonoids in the rooting response of chestnut hybrid (Castanea crenata × Castanea sativa) clones". Australian Journal of Experimental Agriculture 47, n.º 1 (2007): 96. http://dx.doi.org/10.1071/ea05149.
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The involvement of different quercetins [quercetin-3-O-rhamnoside (quercitrin), quercetin-3-D-galactoside (hyperoside) and rutin] and catechins (catechin, catechol) in the rooting process of leafy cuttings was studied in two hybrid chestnut (Castanea crenata × Castanea sativa) clones, Maraval and Marsol. Both clones differed strongly in rooting results. The Maraval clone cuttings, which had a high rooting rate, contained, on average, higher amounts of all quercetins in different plant parts (leaves and basal cuttings) than the Marsol clone, which had a low rooting rate. There was a highly significant correlation between the quercetin contents of the cutting leaves and the rooting process (number of main roots). The catecechin contents of the cutting leaves did not show any correlation with the rooting process.
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Chen, Nannan, Yu Liu, Tongtong Bai, Jinwei Chen, Zhibo Zhao, Jing Li, Baihui Shao et al. "Quercetin Inhibits Hsp70 Blocking of Bovine Viral Diarrhea Virus Infection and Replication in the Early Stage of Virus Infection". Viruses 14, n.º 11 (26 de outubro de 2022): 2365. http://dx.doi.org/10.3390/v14112365.
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Bovine viral diarrhea virus (BVDV), a positive-strand RNA virus of the genus Pestivirus in the Flaviviridae family, is the causative agent of viral diarrheal disease in bovine. BVDV has been used as a surrogate model for the hepatitis C virus (HCV) to evaluate the efficacy of antiviral drugs. The plant flavonol quercetin causes multiple health-promoting effects in humans and animals. It can be made into a variety of additives, and it exerts a variety of immunomodulatory effects with the potential to be used as an antiviral agent. However, quercetin’s antiviral effect and mechanism of action on BVDV are still unclear. Therefore, this study was designed to evaluate quercetin’s effect on BVDV virus replication in vitro and in vivo and elucidate its mechanism of action. A CCK-8 kit was used to analyze the toxicity of the quercetin to the MDBK cells. Western blot, qRT-PCR, TCID50, and histological analysis were used to determine the mechanism of quercetin’s anti-BVDV activity. An oxidative stress kit was used to evaluate the effects of quercetin on ROS, antioxidant enzymes, and MDA indexes. The effect of quercetin on IL-2 and IFN-γ in the serum of mice was determined by using an ELISA kit. The results showed that quercetin inhibits Hsp70, blocks BVDV infection in the early stage of virus infection and inhibits BVDV replication by inhibiting oxidative stress or ERK phosphorylation. In addition, quercetin alleviated the decrease in IFN-γ and IL-2 in the serum of BVDV-infected mice. Quercetin ameliorated BVDV-induced histopathological changes. In summary, this study demonstrated for the first time the role of Hsp70 in BVDV infection and the potential application of quercetin in treating BVDV infection.
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Yuan, Haihua, Hang Xun, Jie Wang, Jin Wang, Xi Yao e Feng Tang. "Integrated Metabolomic and Transcriptomic Analysis Reveals the Underlying Antibacterial Mechanisms of the Phytonutrient Quercetin-Induced Fatty Acids Alteration in Staphylococcus aureus ATCC 27217". Molecules 29, n.º 10 (11 de maio de 2024): 2266. http://dx.doi.org/10.3390/molecules29102266.
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The utilization of natural products in food preservation represents a promising strategy for the dual benefits of controlling foodborne pathogens and enhancing the nutritional properties of foods. Among the phytonutrients, flavonoids have been shown to exert antibacterial effects by disrupting bacterial cell membrane functionality; however, the underlying molecular mechanisms remain elusive. In this study, we investigated the effect of quercetin on the cell membrane permeability of Staphylococcus aureus ATCC 27217. A combined metabolomic and transcriptomic approach was adopted to examine the regulatory mechanism of quercetin with respect to the fatty acid composition and associated genes. Kinetic analysis and molecular docking simulations were conducted to assess quercetin’s inhibition of β-ketoacyl-acyl carrier protein reductase (FabG), a potential target in the bacterial fatty acid biosynthesis pathway. Metabolomic and transcriptomic results showed that quercetin increased the ratio of unsaturated to saturated fatty acids and the levels of membrane phospholipids. The bacteria reacted to quercetin-induced stress by attempting to enhance fatty acid biosynthesis; however, quercetin directly inhibited FabG activity, thereby disrupting bacterial fatty acid biosynthesis. These findings provide new insights into the mechanism of quercetin’s effects on bacterial cell membranes and suggest potential applications for quercetin in bacterial inhibition.
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Buljeta, Ivana, Ina Ćorković, Anita Pichler, Josip Šimunović e Mirela Kopjar. "Application of Citrus and Apple Fibers for Formulation of Quercetin/Fiber Aggregates: Impact of Quercetin Concentration". Plants 11, n.º 24 (19 de dezembro de 2022): 3582. http://dx.doi.org/10.3390/plants11243582.
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Among flavonoids, quercetin has gained special attention due to its positive biological activities. Quercetin’s disadvantages, such as its hydrophobic nature, poor solubility, and permeability, could be overcome by complexation with different polymers. Dietary fibers are known as carriers of polyphenols, which can protect them from environmental conditions and thus allow them to be absorbed. In this study, apple and citrus fibers (as applicable food by-products) were used as carriers of quercetin. A constant amount of fibers (1%) and different concentrations of quercetin solution (5 mM, 10 mM, and 20 mM) were complexed. Obtained fiber aggregates were subjected to HPLC to determine the quercetin concentration and antioxidant activity of aggregates (ABTS, DPPH, FRAP, and CUPRAC assays). IR spectra were recorded to confirm complexation of quercetin with selected fibers, and an additional DSC study was performed to evaluate the thermal stability of fiber aggregates. The results of HPLC analysis showed that quercetin had higher affinity towards apple fiber than citrus fiber, without proportional trends of adsorption. Consequently, apple fiber aggregates had higher antioxidant potential than citrus fiber aggregates. FTIR-ATR analysis showed the formation of new bands and the loss of existing bands when quercetin was present. Adsorption of quercetin also had an impact on the thermal stability of formulated fiber aggregates. For apple fiber, this impact was negative, while for citrus fiber, the impact was positive. These results could contribute to greater understanding of quercetin’s behavior during the preparation of food additives based on polyphenols and fibers.
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Li, Xiu-Mei, Zhong-Yuan Li, Ya-Dong Wang, Jin-Quan Wang e Pei-Long Yang. "Quercetin Inhibits the Proliferation and Aflatoxins Biosynthesis of Aspergillus flavus". Toxins 11, n.º 3 (9 de março de 2019): 154. http://dx.doi.org/10.3390/toxins11030154.
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In this work of quercetin’s anti-proliferation action on A. flavus, we revealed that quercetin can effectively hamper the proliferation of A. flavus in dose-effect and time-effect relationships. We tested whether quercetin induced apoptosis in A. flavus via various detection methods, such as phosphatidylserine externalization and Hoechst 33342 staining. The results showed that quercetin had no effect on phosphatidylserine externalization and cell nucleus in A. flavus. Simultaneously, quercetin reduced the levels of reactive oxygen species (ROS). For a better understanding of the molecular mechanism of the A. flavus response to quercetin, the RNA-Seq was used to explore the transcriptomic profiles of A. flavus. According to transcriptome sequencing data, quercetin inhibits the proliferation and aflatoxin biosynthesis by regulating the expression of development-related genes and aflatoxin production-related genes. These results will provide some theoretical basis for quercetin as an anti-mildew agent resource.
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Wang, Yu Jie, e Bing Wang. "Preparation of Quercetin-Ni+2 Metal-Complexing Imprinted Polymer and its Recognition Performance Evaluation". Applied Mechanics and Materials 275-277 (janeiro de 2013): 1697–700. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.1697.
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Using the complex of quercetin and Ni+2 (quercetin-Ni+2) as template (quercetin is a kind of flavonoids which are important active ingredients of Chinese herbs.), methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linker, metal-complexing template polymer has been prepared in the mixed solution of methanol and tetrahydrofuran by molecular imprinting technique. The coordination structure and complex ratio between quercetin and Ni+2 were studied by UV-visible spectroscopy, and the ternary complexation of quercetin, Ni+2 and methacrylic acid was verified by similar methods. Selective adsorption experiments for substrates indicated that compared with quercetin’s structural analogs (baicalein and baringenin), quercetin-Ni+2 template polymer prepared with appropriate amount of cross-linker exhibited significant adsorption selectivity for quercetin in the presence of Ni+2. The separation factors were 3.915 and 5.443 respectively, which also showed that adsorption capacity was greatly influenced by the amount of cross-linker.
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Singh, Neelam, Mukesh Kumar Meena e Vidya Patni. "HPTLC method for isolation, identification and quantification of quercetin from in vivo and in vitro samples of Naringi Crenulata". Indian Journal of Pharmaceutical and Biological Research 5, n.º 03 (30 de setembro de 2017): 26–31. http://dx.doi.org/10.30750/ijpbr.5.3.4.
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Naringi crenulata(Roxb.) Nicolson, is a rare medicinal plant belonging to the family Rutaceae. It is a spinous tree and has great medicinal value. During the present study a rapid, simple, accurate and specific HPTLC method for quantitative estimation of quercetin present in the dried leaf powder and callus of N. crenulata has been developed .The method used in this work resulted in good peak shape and enabled good resolution of quercetin from N. crenulata samples. Quercetin was identified in in vivo (leaf) and in vitro (six weeks old callus) tissues. Presence of isolated quercetin was further confirmed by superimposable IR spectra of isolated and authentic samples of quercetin and NMR spectra of isolated quercetin. Variation in quercetin content in in vivo and in vitro samples in N. crenulata was observed. In vivo leaf had maximum amount of quercetin (0.13%) while minimum amount was found in in vitro callus (0.032%). High content of quercetin in leaf shows its potential of synthesizing quercetin. This study is also of practical importance because flavonoid quercetin is the most active of all flavonoids. Many medicinal plants owe their activity to their high quercetin content. Several studies revealed quercetin’s significant anti-inflammatory activity due to direct inhibition of initial processes of inflammation. It also has potent antitumor and antioxidant properties including the inhibition of cancer cell proliferation and migration.This study is of practical importance because compound quercetin was firstly reported to be isolated from callus of N. Crenulata.
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Singh, Neelam, Mukesh Kumar Meena e Vidya Patni. "HPTLC method for isolation, identification and quantification of quercetin from in vivo and in vitro samples of Naringi crenulata". Indian Journal of Pharmaceutical and Biological Research 6, n.º 02 (30 de junho de 2018): 05–09. http://dx.doi.org/10.30750/ijpbr.6.2.2.
Texto completo da fonteResumo:
Naringi crenulata (Roxb.) Nicolson, is a rare medicinal plant belonging to the family Rutaceae. It is a spinous tree and has great medicinal value. During the present study a rapid, simple, accurate and specific HPTLC method for quantitative estimation of quercetin present in the dried leaf powder and callus of N. crenulata has been developed .The method used in this work resulted in good peak shape and enabled good resolution of quercetin from N. crenulata samples. Quercetin was identified in in vivo (leaf) and in vitro (six weeks old callus) tissues. Presence of isolated quercetin was further confirmed by superimposable IR spectra of isolated and authentic samples of quercetin and NMR spectra of isolated quercetin. Variation in quercetin content in in vivo and in vitro samples in N. crenulata was observed. In vivo leaf had maximum amount of quercetin (0.13%) while minimum amount was found in in vitro callus (0.032%). High content of quercetin in leaf shows its potential of synthesizing quercetin. This study is also of practical importance because flavonoid quercetin is the most active of all flavonoids. Many medicinal plants owe their activity to their high quercetin content. Several studies revealed quercetin’s significant anti-inflammatory activity due to direct inhibition of initial processes of inflammation. It also has potent antitumor and antioxidant properties including the inhibition of cancer cell proliferation and migration. This study is of practical importance because compound quercetin was firstly reported to be isolated from callus of N. crenulata
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Sudjarwo. "Determination of Queercetin Content in Preparation of Powder Extract of Starfruit Leaves (Averrhoa bilimbi L.) by TLC-Densitometry". Berkala Ilmiah Kimia Farmasi 10, n.º 1 (30 de junho de 2023): 1–6. http://dx.doi.org/10.20473/bikfar.v10i1.51432.
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Quercetin is a flavonoid from Averrhoa bilimbi Linn. which has a variety of potential therapeutic. Therefore, this research is needed to determine the quercetin content in Averrhoa bilimbi L.’s extract powder. Method Validation is performed to ensure that an analytical method meets the criteria and requirements of a good analysis method. Method Validation used was the first category with parameters of selectivity, linearity, accuracy, and precision. The quercetin content in Averrhoa bilimbi L.’s leaf was small, requiring a parameter Limit of Detection (LOD) and Limit of Quantitation (LOQ). The analysis method was by TLC-Densitometry with Silica gel 60 F254, eluent of toluene: ethyl acetate: formic acid (7:3:1) as mobile phase with a resolution of 1.67 and 1.60 respectively. The result showed linear regression of y = 8122.4899 x + 1181.9943 (r: 0.9976; Vxo 4.88%). The accuracy was 90.2 % (w/w) ± 5.89; the coefficient of variation of precision was 1.35%; LOD and LOQ were 0.0064 µg, and 0.0215 µg respectively. The determination result showed that quercetine content in the leaf extract in ethanol of Averrhoa bilimbi L. was 0.58% (w/w) ± 0.04 and the determination quercetin from 4.0 g extract powder of Averrhoa bilimbi L. leaf showed that average content of quercetine was 6.05 ± 0.09 mg. Keywords: Quercetin, Extract Powder, Averrhoa bilimbi L, TLC-Densitometry
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Jung, Min Kyung, e Dae-Ho Cho. "Tannic acid and quercetin display a therapeutic effect on atopic dermatitis via suppression of angiogenesis and Th2 polarization. (97.7)". Journal of Immunology 184, n.º 1_Supplement (1 de abril de 2010): 97.7. http://dx.doi.org/10.4049/jimmunol.184.supp.97.7.
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Abstract Atopic dermatitis (AD) is a chronic inflammatory skin disease that is characterized by inflammation, abnormal angiogenesis and elevated Th2 polarization. Tannic acid (TA) and quercetin are well known polypenolic compounds, have documented anti-inflammatory effect. However, little is known about the effects of TA and quercetin on atopic dermatitis and related mechanisms. The present study investigated whether TA and quercetin had a therapeutic effect on atopic dermatitis. In vitro, we found that TA and quercetins reduced pro-angiogenic factor and Th2-inducing cytokine in human keratinocytes. The inhibitory effect was higher in the combined application of the two agents than in the application of one agent alone. To investigate the effect of combined application with TA and quercetin in vivo, an AD-induced Nc/Nga mouse model was used. The group receiving TA and quercetin showed disease improvement with down-regulation of serum IgE, TARC production and angiogenesis level compare to non-treated group. Taken together, these data demonstrate that TA and quercetin have a therapeutic effect on AD by suppressing angiogenesis, Th2 polarization.
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Vendramin, Veronica, Daniele Pizzinato, Céline Sparrow, Daniele Pagni, Fabio Cascella, Claudio Carapelli e Simone Vincenzi. "Prevention of quercetin precipitation in red wines: a promising enzymatic solution". OENO One 56, n.º 1 (10 de janeiro de 2022): 41–51. http://dx.doi.org/10.20870/oeno-one.2022.56.1.4699.
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Flavonols are known for causing undesirable deposits in both red and white wines. Among flavonols, quercetin is widely considered the principal factor determining this phenomenon. One of the most accredited hypotheses claims that glycosylated derivatives of quercetin undergo hydrolysis of the glycosylic bond during the fermentation and the wine ageing, releasing quercetin aglycone, which is much less soluble in water solution and causes the precipitation. Our work describes the dynamics of quercetin-derived deposition in Chianti wines and purposes a new method, based on the enzymatic quercetin glycoside hydrolysis of the glycosidic bond, to prevent the unpleasant deposit formation during the wine ageing. In our study, forty-four monovarietal wines obtained from 7 different Italian grape varieties were compared in the content of total quercetin-3-glycosides (rutin, quercetin-3-glucuronide, quercetin-3-glucoside) and quercetin aglycone. The data confirmed the literature revealing Sangiovese as the richest in quercetin. We tested then, in a Sangiovese wine, four fining agents (PVPP, PVPP/PVI, bentonite and a vegetal protein) for quercetin removal, showing that only the PVPP had a modest aglycone removal activity. Then, the kinetics of deposit formation was studied in three Chianti wines which differed in the initial content of quercetin aglycone. This investigation highlighted that the chemical equilibrium of quercetin changes over time as the turbidity slowly increases, as previously documented. The comparison of the three dynamics also permitted us to conclude that different wines show a different ability to keep in solution quercetin. Finally, a new approach for deposit prevention was studied by a precocious Chianti wine treatment with a pectolytic enzyme having secondary glycosidase activity. This enzyme significantly accelerated the hydrolysis of glycosylated quercetins into their aglycone, which could enhance the deposition before bottling, without serious wine colour depletion. Our study represents the first evidence of the promising potential of using the pectolytic enzyme with secondary glycosidase activity to prevent quercetin deposit during Chianti ageing, in a way that is compatible with organic wine production.
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Guan, Hui, Wenyuan Zhang, Hui Liu, Yang Jiang, Feng Li, Maoyu Wu, Geoffrey I. N. Waterhouse, Dongxiao Sun-Waterhouse e Dapeng Li. "Quercetin Induces Apoptosis in HepG2 Cells via Directly Interacting with YY1 to Disrupt YY1-p53 Interaction". Metabolites 13, n.º 2 (3 de fevereiro de 2023): 229. http://dx.doi.org/10.3390/metabo13020229.
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Quercetin is a flavonol found in edible plants and possesses a significant anticancer activity. This study explored the mechanism by which quercetin prevented liver cancer via inducing apoptosis in HepG2 cells. Quercetin induced cell proliferation and apoptosis through inhibiting YY1 and facilitating p53 expression and subsequently increasing the Bax/Bcl-2 ratio. The results revealed that YY1 knockdown promoted apoptosis, whilst YY1 overexpression suppressed apoptosis via direct physical interaction between YY1 and p53 to regulate the p53 signaling pathway. Molecular docking using native and mutant YY1 proteins showed that quercetin could interact directly with YY1, and the binding of quercetin to YY1 significantly decreased the docking energy of YY1 with p53 protein. The interactions between quercetin and YY1 protein included direct binding and non-bonded indirect interactions, as confirmed by cellular thermal shift assay, UV-Vis absorption spectroscopy, fluorescence spectroscopy and circular dichroism spectroscopy. It was likely that quercetin directly bound to YY1 protein to compete with p53 for the binding sites of YY1 to disrupt the YY1-p53 interaction, thereby promoting p53 activation. This study provides insights into the mechanism underlying quercetin’s anticancer action and supports the development of quercetin as an anticancer therapeutic agent.
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Gao, Min, e Guang-Yan Tang. "Structural Basis for Great Protein-Binding Potential of Flavonoids: A Case Study of Quercetin". Natural Product Communications 12, n.º 11 (novembro de 2017): 1934578X1701201. http://dx.doi.org/10.1177/1934578x1701201142.
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Flavonoids exhibit a wide variety of biological effects and hold great protein-binding potential. In this study, we take quercetin, an extensively studied flavonoid, as an example to investigate the structural basis underlying their excellent protein-binding ability. Through calculating the pocket similarity of quercetin-binding proteins and comparing the binding modes between quercetins bound with different proteins, it was found that the great protein-binding capacity of quercetin not only arises from the structural conservation of target proteins, but also stems from its unique structure, in which molecular rigidity and flexibility is well-balanced and various chemical interactions could be formed between the small molecule and protein targets.
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Kothan, S., S. Dechsupa, G. Leger, J. L. Moretti, J. Vergote e S. Mankhetkorn. "Spontaneous mitochondrial membrane potential change during apoptotic induction by quercetin in K562 and K562/adr cells". Canadian Journal of Physiology and Pharmacology 82, n.º 12 (1 de dezembro de 2004): 1084–90. http://dx.doi.org/10.1139/y04-113.
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Natural products from plants such as flavonoids are potential drugs to overcome multidrug resistance (MDR) in cancer treatments. However, their modes of action are still unclear. In this study, the effects of quercetin on mitochondrial membrane potential (ΔΨm) change as well as quercetin's ability to induce apoptosis and inhibit Pgp-mediated efflux of 99mTc-MIBI in K562/adr cells were investigated. Quercetin exhibits cytotoxicity against erythroleukemic cells: IC50 are 11.0 ± 2.0 µmol/L and 5.0 ± 0.4 µmol/L for K562 and K562/adr, respectively. Quercetin induces cell death via apoptosis in both K562 and K562/adr cells and does not inhibit Pgp-mediated efflux of 99mTc-MIBI. Quercetin (10 µmol/L, 3 h) and etoposide (100 µmol/L, 24 h) induce similar levels of apoptosis in K562 and K562/adr cells. Quercetin induces an increase followed by a decrease in |ΔΨm| value depending on its concentration. A decrease in the |ΔΨm| value is associated with an increase in the percentage of early apoptotic cells. It is clearly shown that quercetin results in a spontaneous ΔΨm change during apoptotic induction. Therefore, quercetin is potentially an apoptotic-inducing agent, which reacts at the mitochondrial level.Key words: multidrug resistance (MDR), quercetin, apoptosis, 99mTc-Annexin V, mitochondrial membrane potential (ΔΨm), 99mTc-MIBI.
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Guo, Chao, Wen-Jun Wang, Yu-Cheng Liao, Chao Zhao, Ying Yin, Min-Na Yao, Yi Ding e Jing-Wen Wang. "Effect and Mechanisms of Quercetin for Experimental Focal Cerebral Ischemia: A Systematic Review and Meta-Analysis". Oxidative Medicine and Cellular Longevity 2022 (25 de fevereiro de 2022): 1–13. http://dx.doi.org/10.1155/2022/9749461.
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Quercetin, a naturally occurring flavonoid, is mainly extracted from tea, onions, and apples. It has the underlying neuroprotective effect on experimental ischemic stroke. A systematic review and meta-analysis were used to assess quercetin’s efficacy and possible mechanisms in treating focal cerebral ischemia. Compared with the control group, twelve studies reported a remarkable function of quercetin in improving the neurological function score (NFS) ( P < 0.05 ), and twelve studies reported a significant effect on reducing infarct volume ( P < 0.05 ). Moreover, two and three studies showed that quercetin could alleviate blood-brain barrier (BBB) permeability and brain water content, respectively. The mechanisms of quercetin against focal cerebral ischemia are diverse, involving antioxidation, antiapoptotic, anti-inflammation, and calcium overload reduction. On the whole, the present study suggested that quercetin can exert a protective effect on experimental ischemic stroke. Although the effect size may be overestimated because of the quality of studies and possible publication bias, these results indicated that quercetin might be a promising neuroprotective agent for human ischemic stroke. This study is registered with PROSPERO, number CRD 42021275656.
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Ruiz, Lina M., Celia Salazar, Erik Jensen, Paula A. Ruiz, William Tiznado, Rodrigo A. Quintanilla, Marlen Barreto e Alvaro A. Elorza. "Quercetin Affects Erythropoiesis and Heart Mitochondrial Function in Mice". Oxidative Medicine and Cellular Longevity 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/836301.
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Quercetin, a dietary flavonoid used as a food supplement, showed powerful antioxidant effects in different cellular models. However, recentin vitroandin vivostudies in mammals have suggested a prooxidant effect of quercetin and described an interaction with mitochondria causing an increase inO2∙-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 quercetinin vivoto 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.
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Laksmiani, Ni Putu Linda, I. Wayan Agus Widiantara e Andrew Borneo Salian Pawarrangan. "Potency of moringa (Moringa oleifera L.) leaves extract containing quercetin as a depigmentation agent inhibiting the tyrosinase enzyme using in-silico and in-vitro assay". Pharmacia 69, n.º 1 (19 de janeiro de 2022): 85–92. http://dx.doi.org/10.3897/pharmacia.69.e73132.
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Hyperpigmentation is a disorder of facial skin pigments due to an increase in the process of melanogenesis, which can cause a darkening of skin color. A flavonoid compound with potential as a skin-lightening agent is quercetin, commonly found in Moringa oleifera L. leaves. This study aims to determine quercetin’s affinity and molecular mechanism on tyrosinase enzyme target proteins using an in-silico molecular docking method. Docking of quercetin with the tyrosinase enzyme produced a bond energy value of -7.08 kcal/mol. In comparison, the tropolone as a native ligand with the tyrosinase enzyme produced -4.79 kcal/mol. Quercetin has a strong affinity for the tyrosinase enzyme, indicated by the bond energy results from docking. Quercetin extraction from Moringa oleifera L. leaves using three different extraction methods: maceration, soxhlation, and reflux were made. The chromatogram from the TLC-Densitometry method showed the identification result in maceration and soxhlation extract containing quercetin, while reflux extract did not contain quercetin. The highest quercetin was obtained in the maceration method with a level of 21.57% w/w, while the soxhlation received quercetin as much as 18.49% w/w. In-vitro tests were carried out using a spectrophotometric method using a comparison of kojic acid. The in-vitro test found that IC50 from kojic acid was 48.90 µg/mL and IC50 of the extract from moringa leaf maceration of 115.36 µg/mL. Based on this research, quercetin compounds in Moringa oleifera L. leaves from maceration can potentially be skin-lightening agents.
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Koleini, Toktam Sadat, Seyed Jalal Zargar, Shahrokh Safarian e Mostafa Saberian. "Increasing the Sensitivity of MCF-7 Breast Cancer Cells to Quercetin by Declining DFF45 Expression Level". Jundishapur journal of Medical Sciences 21, n.º 6 (1 de julho de 2023): 776–92. http://dx.doi.org/10.32598/jsmj.21.6.2435.
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Background and Objectives In recent years, flavonoids such as quercetin have been considered as new anticancer drugs. The mechanisms of action of quercetin include cell cycle arrest, inhabitation of cell proliferation, and induction of apoptosis. This study aims to reduce quercetin’s side effects by increasing MCF-7 breast cancer cells’ sensitivity to this drug and facilitating the cytotoxic effects of quercetin at lower concentrations. Subjects and Methods In this study, the MTT assay was used to determine the concentration that reduced the cell viability by 50% (i.e. lethal concentration 50 or LC50). Then, the expression of the DNA fragmentation factor-45 (DFF45) and some genes in the apoptosis pathway (caspase3, p53, BAX, BCL-2, AIF), the autophagy pathway (LC3, ATG5, Beclin, DRAM) and the AKT/mTOR pathway (AKT1, mTOR, and PTEN), in cells treated with siRNA, quercetin, and quercetin+siRNA using the real-time PCR. Results According to the results of MTT assay, the LC50 value for quercetin was determined 220 μM. The results indicated the initiation of cell death through autophagy pathways. The combined treatment (quercetin+siRNA) increased the mechanism of cancer cell death more than the quercetin treatment alone. Conclusion One of the regulating pathways of apoptosis is forcing the inhibitory effect of DFF45 on DFF40/CAD nuclease. Down regulation of DFF45, along with quercetin administration, can lead to induction of breast cancer cell death which can be a novel technique for the treatment of breast cancer.
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Seo, Sang Young, Won Seok Ju, Kyongtae Kim, Juhwan Kim, Jin Ok Yu, Jae-Sung Ryu, Ji-Su Kim, Hyun-A. Lee, Deog-Bon Koo e Young-Kug Choo. "Quercetin Induces Mitochondrial Apoptosis and Downregulates Ganglioside GD3 Expression in Melanoma Cells". International Journal of Molecular Sciences 25, n.º 10 (9 de maio de 2024): 5146. http://dx.doi.org/10.3390/ijms25105146.
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Malignant melanoma represents a form of skin cancer characterized by a bleak prognosis and heightened resistance to traditional therapies. Quercetin has demonstrated notable anti-carcinogenic, anti-inflammatory, anti-oxidant, and pharmacological effects across various cancer types. However, the intricate relationship between quercetin’s anti-cancer properties and ganglioside expression in melanoma remains incompletely understood. In this study, quercetin manifests specific anti-proliferative, anti-migratory, and cell-cycle arrest effects, inducing mitochondrial dysfunction and apoptosis in two melanoma cancer cell lines. This positions quercetin as a promising candidate for treating malignant melanoma. Moreover, our investigation indicates that quercetin significantly reduces the expression levels of ganglioside GD3 and its synthetic enzyme. Notably, this reduction is achieved through the inhibition of the FAK/paxillin/Akt signaling pathway, which plays a crucial role in cancer development. Taken together, our findings suggest that quercetin may be a potent anti-cancer drug candidate for the treatment of malignant melanoma.
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Rayamajhi, Nabin, Seul-Ki Kim, Hiroe Go, Yeonsoo Joe, Zak Callaway, Jae-Gu Kang, Stefan W. Ryter e Hun Taeg Chung. "Quercetin Induces Mitochondrial Biogenesis through Activation of HO-1 in HepG2 Cells". Oxidative Medicine and Cellular Longevity 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/154279.
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The regeneration of mitochondria by regulated biogenesis plays an important homeostatic role in cells and tissues and furthermore may provide an adaptive mechanism in certain diseases such as sepsis. The heme oxygenase (HO-1)/carbon monoxide (CO) system is an inducible cytoprotective mechanism in mammalian cells. Natural antioxidants can provide therapeutic benefit, in part, by inducing the HO-1/CO system. This study focused on the mechanism by which the natural antioxidant quercetin can induce mitochondrial biogenesis in HepG2 cells. We found that quercetin treatment induced expression of mitochondrial biogenesis activators (PGC-1α, NRF-1, TFAM), mitochondrial DNA (mtDNA), and proteins (COX IV) in HepG2 cells. The HO inhibitor SnPP and the CO scavenger hemoglobin reversed the effects of quercetin on mitochondrial biogenesis in HepG2 cells. The stimulatory effects of quercetin on mitochondrial biogenesis could be recapitulatedin vivoin liver tissue and antagonized by SnPP. Finally, quercetin conferred an anti-inflammatory effect in the liver of mice treated with LPS and prevented impairment of mitochondrial biogenesis by LPSin vivo. These salutary effects of quercetinin vivowere also antagonized by SnPP. Thus, our results suggest that quercetin enhances mitochondrial biogenesis mainly via the HO-1/CO systemin vitroandin vivo. The beneficial effects of quercetin may provide a therapeutic basis in inflammatory diseases and sepsis.
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Oh, Won Jun, Mehari Endale, Seung-Chun Park, Jae Youl Cho e Man Hee Rhee. "Dual Roles of Quercetin in Platelets: Phosphoinositide-3-Kinase and MAP Kinases Inhibition, and cAMP-Dependent Vasodilator-Stimulated Phosphoprotein Stimulation". Evidence-Based Complementary and Alternative Medicine 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/485262.
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Background. Progressive diseases including cancer, metabolic, and cardiovascular disorders are marked by platelet activation and chronic inflammation. Studies suggest that dietary flavonoids such as quercetin possess antioxidant, anti-inflammatory, and antiplatelet properties, which could prevent various chronic diseases including atherosclerosis and thrombosis. However, the mechanism and the signaling pathway that links quercetin's antiplatelet activity with its anti-inflammatory property is limited and thus further exploration is required. The aim of this paper was to examine the link between antiplatelet and anti-inflammatory roles of quercetin in agonist-induced platelet activation.Methods. Quercetin effects on agonist-activated platelet-aggregation, granule-secretion,[Ca2+]i, and glycoprotein-IIb/IIIa activation were examined. Its effects on PI3K/Akt, VASP, and MAPK phosphorylations were also studied on collaged-activated platelets.Results. Quercetin dose dependently suppressed collagen, thrombin, or ADP-induced platelet aggregation. It significantly inhibited collagen-induced ATP release, P-selectin expression,[Ca2+]imobilization, integrin-αIIbβ3activation, and augmented cAMP and VASP levels. Moreover, quercetin attenuated PI3K, Akt, ERK2, JNK1, and p38 MAPK activations, which were supported by platelet-aggregation inhibition with the respective kinase inhibitors.Conclusion. Quercetin-mediated antiplatelet activity involves PI3K/Akt inactivation, cAMP elevation, and VASP stimulation that, in turn, suppresses MAPK phosphorylations. This result suggests quercetin may have a potential to treat cardiovascular diseases involving aberrant platelet activation and inflammation.
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Aghababaei, Fatemeh, e Milad Hadidi. "Recent Advances in Potential Health Benefits of Quercetin". Pharmaceuticals 16, n.º 7 (18 de julho de 2023): 1020. http://dx.doi.org/10.3390/ph16071020.
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Quercetin, a flavonoid found in fruits and vegetables, has been a part of human diets for centuries. Its numerous health benefits, including antioxidant, antimicrobial, anti-inflammatory, antiviral, and anticancer properties, have been extensively studied. Its strong antioxidant properties enable it to scavenge free radicals, reduce oxidative stress, and protect against cellular damage. Quercetin’s anti-inflammatory properties involve inhibiting the production of inflammatory cytokines and enzymes, making it a potential therapeutic agent for various inflammatory conditions. It also exhibits anticancer effects by inhibiting cancer cell proliferation and inducing apoptosis. Finally, quercetin has cardiovascular benefits such as lowering blood pressure, reducing cholesterol levels, and improving endothelial function, making it a promising candidate for preventing and treating cardiovascular diseases. This review provides an overview of the chemical structure, biological activities, and bioavailability of quercetin, as well as the different delivery systems available for quercetin. Incorporating quercetin-rich foods into the diet or taking quercetin supplements may be beneficial for maintaining good health and preventing chronic diseases. As research progresses, the future perspectives of quercetin appear promising, with potential applications in nutraceuticals, pharmaceuticals, and functional foods to promote overall well-being and disease prevention. However, further studies are needed to elucidate its mechanisms of action, optimize its bioavailability, and assess its long-term safety for widespread utilization.
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Aditi Gajanan Asole e Madhuri D. Game. "A novel stability indicating HPTLC method for comparative quantitative estimation of quercetin in herbal preparations". GSC Biological and Pharmaceutical Sciences 27, n.º 2 (30 de maio de 2024): 262–75. http://dx.doi.org/10.30574/gscbps.2024.27.2.0178.
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This research introduces a novel stability-indicating HPTLC (High-Performance Thin-Layer Chromatography) method for the comparative quantitative estimation of Quercetin in herbal preparations. Through extensive stability studies, the method is validated, providing a robust framework for evaluating Quercetin's stability in diverse herbal formulations. The developed method ensures accurate and reliable quantification of Quercetin, facilitating comparative analysis across various herbal preparations. Additionally, results reveal that Quercetin degraded under most tested conditions, such as acidic, alkaline, oxidative and neutral conditions underscoring the necessity for intervention by experts to eliminate such challenges and ensure product efficacy and quality in the herbal industry.
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Sakao, Kozue, Hanako Saruwatari, Shohei Minami e De-Xing Hou. "Hydroxyl Group Acetylation of Quercetin Enhances Intracellular Absorption and Persistence to Upregulate Anticancer Activity in HepG2 Cells". International Journal of Molecular Sciences 24, n.º 23 (23 de novembro de 2023): 16652. http://dx.doi.org/10.3390/ijms242316652.
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Quercetin, a flavonoid compound widely distributed in many plants, is known to have potent antitumor effects on several cancer cells. Our previous study revealed that the acetylation of quercetin enhanced its antitumor effect. However, the mechanisms remain unknown. This study aimed to elucidate the bioavailability of acylated quercetin in the HepG2 cell model based on its antitumor effect. The positions of quercetin 3,7,3′,4′-OH were acetylated as 3,7,3′,4′-O-tetraacetylquercetin (4Ac-Q). The inhibitory effect of 4Ac-Q on HepG2 cell proliferation was assessed by measuring cell viability. The apoptosis was characterized by apoptotic proteins and mitochondrial membrane potential shifts, as well as mitochondrial reactive oxygen species (ROS) levels. The bioavailability of 4Ac-Q was analyzed by measuring the uptake and metabolites in HepG2 cells with high performance liquid chromatography (HPLC)—photodiode array detector (PDA) and—ultraviolet/visible detector (UV/Vis). The results revealed that 4Ac-Q enhanced the inhibitory effect on HepG2 cell proliferation and induced its apoptosis significantly higher than quercetin. Protein array analysis of apoptosis-related protein indicated that 4Ac-Q increased the activation or expression of pro-apoptotic proteins, including caspase-3, -9, as well as second mitochondria-derived activator of caspases (SMAC), and suppressed the expression of apoptosis inhibiting proteins such as cellular inhibitor of apoptosis (cIAP)-1, -2, Livin, Survivin, and X-linked inhibitor of apoptosis (XIAP). Furthermore, 4Ac-Q stimulated mitochondrial cytochrome c release into the cytosol by enhancing ROS level and depolarizing the mitochondrial membrane. Finally, the analysis of uptake and metabolites of 4Ac-Q in HpG2 cells with HPLC-PDA and -UV/Vis revealed that 4Ac-Q was metabolized to quercetin and several different acetylated quercetins which caused 2.5-fold higher quercetin present in HepG2 cells than parent quercetin. These data demonstrated that acetylation of the quercetin hydroxyl group significantly increased its intracellular absorption. Taken together, our findings provide the first evidence that acetyl modification of quercetin not only substantially augments the intracellular absorption of quercetin but also bolsters its metabolic stability to elongate its intracellular persistence. Therefore, acetylation could serve as a strategic approach to enhance the ability of quercetin and analogous flavonoids to suppress cancer cell proliferation.
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Jambor, Jerzy, e Lutosława Skrzypczak. "Flavonoids from the flowers of Nymphaea alba L." Acta Societatis Botanicorum Poloniae 60, n.º 1-2 (2014): 119–25. http://dx.doi.org/10.5586/asbp.1991.010.
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Ten flavonoids were obtained from the flowers of <i>Nymphaea alba</i> L. Their structures were determined mainly on the basis of spectral analyses (UV, 'H NMR, MS). The following aglycons were isolated: quercetin, kaempferol, isokaempferide and apigenin as well as the following glycosides: quercetion 4'-β-xyloside, 3-methylquercetin 3'-β-xyloside and a mixture of quercetin 3-galactoside and 3-glucoside. The structures of three compounds obtained in very small amounts were determined in part.
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Oo, Aung Myo, Mohd Nasir Mat Nor, Ohn Mar Lwin e Nordin Simbak. "Flavonol Quercetin: Immunomodulatory And Anticancer Properties". Asian Journal of Medicine and Biomedicine 6, n.º 1 (30 de abril de 2022): 17–31. http://dx.doi.org/10.37231/ajmb.2022.6.1.452.
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Background: Cancer is one of the critical, challenging problems in a clinical setting among non-infectious diseases and poses a considerable burden to the community for its highest fatalities and associated morbidities. Immunotherapy has paid much attention to curbing cancer and protecting against advanced metastasis. Nutritional sources have been well known for their anticancer properties for centuries, although they exhibited multiple intricated mechanisms to deter this notorious disease. Immune-based therapy is getting popular in modern days to fight against various illnesses, including cancer. In recent years, numerous in vitro and clinical trials have been carried out regarding the potential use of flavonoids in cancer therapy; however, the results and achievements were still controversial and obscure. More research on immune-mediated anticancer therapy has to be done to understand more explicit mechanisms of how plant-derived compounds modulate immune cells and subsequent clinical uses. One of the most commonly tested flavonoid compounds that stimulate immune cells and offer significant immune-mediated anticancer activities is flavonol quercetin.
Objectives: This present review summarises an updated overview of quercetin, focusing on its anticancer effects. In addition to its chemistry and sources, quercetin’s immunomodulatory properties and the common signalling mechanisms have also been described and proposed the possible research gap for further investigation and future research.
Conclusion: This review would provide a new comparative view regarding quercetin’s immunomodulatory and anticancer activities. Moreover, we conclude that quercetin plays a crucial role in eradicating cancer cells and modulating immune cells’ activity based on the literature. It is worthwhile to extensively investigate quercetin’s anticancer and immunomodulatory effects in clinical settings.
Key words: Cancer, flavonol, quercetin, anticancer, immunomodulation
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Xu, Baoyang, Wenxia Qin, Yunzheng Xu, Wenbo Yang, Yuwen Chen, Juncheng Huang, Jianan Zhao e Libao Ma. "Dietary Quercetin Supplementation Attenuates Diarrhea and Intestinal Damage by Regulating Gut Microbiota in Weanling Piglets". Oxidative Medicine and Cellular Longevity 2021 (13 de dezembro de 2021): 1–19. http://dx.doi.org/10.1155/2021/6221012.
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Antioxidant polyphenols from plants are potential dietary supplementation to alleviate early weaning-induced intestinal disorders in piglets. Recent evidences showed polyphenol quercetin could reshape gut microbiota when it functioned as anti-inflammation or antioxidation agents in rodent models. However, the effect of dietary quercetin supplementation on intestinal disorders and gut microbiota of weanling piglets, along with the role of gut microbiota in this effect, both remain unclear. Here, we determined the quercetin’s effect on attenuating diarrhea, intestinal damage, and redox imbalance, as well as the role of gut microbiota by transferring the quercetin-treated fecal microbiota to the recipient piglets. The results showed that dietary quercetin supplementation decreased piglets’ fecal scores improved intestinal damage by increasing tight junction protein occludin, villus height, and villus height/crypt depth ratio but decreased crypt depth and intestinal epithelial apoptosis (TUNEL staining). Quercetin also increased antioxidant capacity indices, including total antioxidant capacity, catalase, and glutathione/oxidized glutathione disulfide but decreased oxidative metabolite malondialdehyde in the jejunum tissue. Fecal microbiota transplantation (FMT) from quercetin-treated piglets had comparable effects on improving intestinal damage and antioxidative capacity than dietary quercetin supplementation. Further analysis of gut microbiota using 16S rDNA sequencing showed that dietary quercetin supplementation or FMT shifted the structure and increased the diversity of gut microbiota. Especially, anaerobic trait and carbohydrate metabolism functions of gut microbiota were enriched after dietary quercetin supplementation and FMT, which may owe to the increased antioxidative capacity of intestine. Quercetin increased the relative abundances of Fibrobacteres, Akkermansia muciniphila, Clostridium butyricum, Clostridium celatum, and Prevotella copri but decreased the relative abundances of Proteobacteria, Lactobacillus coleohominis, and Ruminococcus bromii. Besides, quercetin-shifted bacteria and carbohydrate metabolites short chain fatty acids were significantly related to the indices of antioxidant capacity and intestinal integrity. Overall, dietary quercetin supplementation attenuated diarrhea and intestinal damage by enhancing the antioxidant capacity and regulating gut microbial structure and metabolism in piglets.
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Nguyen, Thi Lan Anh, e Debanjana Bhattacharya. "Antimicrobial Activity of Quercetin: An Approach to Its Mechanistic Principle". Molecules 27, n.º 8 (12 de abril de 2022): 2494. http://dx.doi.org/10.3390/molecules27082494.
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Quercetin, an essential plant flavonoid, possesses a variety of pharmacological activities. Extensive literature investigates its antimicrobial activity and possible mechanism of action. Quercetin has been shown to inhibit the growth of different Gram-positive and Gram-negative bacteria as well as fungi and viruses. The mechanism of its antimicrobial action includes cell membrane damage, change of membrane permeability, inhibition of synthesis of nucleic acids and proteins, reduction of expression of virulence factors, mitochondrial dysfunction, and preventing biofilm formation. Quercetin has also been shown to inhibit the growth of various drug-resistant microorganisms, thereby suggesting its use as a potent antimicrobial agent against drug-resistant strains. Furthermore, certain structural modifications of quercetin have sometimes been shown to enhance its antimicrobial activity compared to that of the parent molecule. In this review, we have summarized the antimicrobial activity of quercetin with a special focus on its mechanistic principle. Therefore, this review will provide further insights into the scientific understanding of quercetin’s mechanism of action, and the implications for its use as a clinically relevant antimicrobial agent.
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Ragunath, Ravichandiran, Bichandarkoil Jayaram Pratima, Briska Jifrina Premnath e Namasivayam Nalini. "Quercetin Prevents Bisphenol S Induced Behavioral Changes and Oxidative Stress iZebrafish by Modulating Brain Antioxidant Defense Mechanism". Biosciences Biotechnology Research Asia 19, n.º 3 (29 de setembro de 2022): 589–600. http://dx.doi.org/10.13005/bbra/3012.
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ABSTRACT: The man-made xenoestrogen bisphenol S has been well-established and associated with developing neoplasm, dementia, neurotoxicity, anxiety, and other adverse effects in people and other organisms. The mechanisms of BPS-induced toxicity have been studied; however, it is unclear if there is any prospect for improvement by natural means. After being exposed to BPS through water, zebrafish (Danio rerio) were employed in this investigation to determine whether quercetin co-supplementation could lessen the compound's destructive potential. Laboratory tests were done to see if quercetin's antioxidant properties may shield the zebrafish brain from oxidative stress and altered behavioral responses brought on by BPS. The available evidence shows that quercetin is beneficial in reducing the abnormal behavioral response brought on by BPS. Quercetin (QU) may have therapeutic potential for reducing oxidative stress caused by BPS, according to biochemical research conducted in the zebrafish brain. In addition, quercetin guards the zebrafish brain against toxicity brought on by BPS. These preliminary findings imply that quercetin, which reduces the generation of reactive oxygen species, would be an effective treatment for BPS-induced toxicity in zebrafish.
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Abdu, Suzan, Nouf Juaid, Amr Amin, Mohamed Moulay e Nabil Miled. "Effects of Sorafenib and Quercetin Alone or in Combination in Treating Hepatocellular Carcinoma: In Vitro and In Vivo Approaches". Molecules 27, n.º 22 (21 de novembro de 2022): 8082. http://dx.doi.org/10.3390/molecules27228082.
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Sorafenib is the first drug approved to treat advanced hepatocellular carcinoma (HCC) and continues as the gold-standard therapy against HCC. However, acquired drug resistance represents a main concern about sorafenib therapy. The flavanol quercetin found in plants has shown great anti-cancer and anti-inflammatory properties. In this work, quercetin was used as a therapeutic agent alone or in combination with a sorafenib chemotherapy drug to improve the routine HCC treatment with sorafenib. The in vitro and in vivo results presented here confirm that quercetin alone or in combination with sorafenib significantly inhibited HCC growth, induced cell cycle arrest and induced apoptosis and necrosis. Further molecular data shown in this report demonstrate that quercetin alone or combined with sorafenib downregulated key inflammatory, proliferative and angiogenesis-related genes (TNF-α, VEGF, P53 and NF-κB). Combined quercetin/sorafenib treatment markedly improved the morphology of the induced liver damage and showed significant antioxidant and anti-tumor effects. The advantage of combined treatment efficacy reported here can be attributed to quercetin’s prominent effects in modulating cell cycle arrest, apoptosis, oxidative stress and inflammation.
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Jiang, Maocheng, Kexin Wang, Yinghao Huang, Xuelei Zhang, Tianyu Yang, Kang Zhan e Guoqi Zhao. "Quercetin Alleviates Lipopolysaccharide-Induced Cell Oxidative Stress and Inflammatory Responses via Regulation of the TLR4-NF-κB Signaling Pathway in Bovine Rumen Epithelial Cells". Toxins 15, n.º 8 (21 de agosto de 2023): 512. http://dx.doi.org/10.3390/toxins15080512.
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Subacute rumen acidosis (SARA) will cause an increase in endotoxin, which will have a negative effect on the bovine rumen epithelial cells (BREC). Flavonoids are effective in treating inflammation caused by endotoxin. Quercetin is a vital flavonoid widely occurring in fruits and vegetables and has received significant interest as a prospective anti-inflammatory antioxidant. Nonetheless, quercetin’s protective machinery against such damage to BREC induced by lipopolysaccharide (LPS) remains unclear. A combined quercetin and LPS-induced BREC inflammation model was utilized to elucidate the effect of quercetin protecting BREC from LPS-induced injury. After treating BREC with different doses of LPS (1, 5, and 10 μg/mL) for 6 h or 24 h, the mRNA expression of inflammatory factors was detected. Our experimental results show the establishment of the BREC inflammation model via mRNA high expression of pro-inflammatory cytokines in BREC following 6 h treatment with 1 µg/mL LPS. The promotive effect of 80 μg/mL quercetin on BREC growth via the cell counting kit-8 (CCK8) assay was observed. The expression of pro-inflammatory cytokines and chemokines, notably tumor necrosis factor α (TNF-α), Interleukin 1β (IL-1β), IL-6, CC-motif chemokine ligand 2 (CCL2), CCL20, CCL28, and CXC motif chemokine 9 (CXCL9), etc., was significantly reduced by quercetin supplementation. We also analyzed the mRNA detection of related pathways by qRT-PCR. Our validation studies demonstrated that quercetin markedly curbed the mRNA expression of the toll-like receptor 4 (TLR4) and myeloid differentiation primary response protein (MyD88) and the nuclear factor-κB (NF-κB) in LPS-treated BREC. In addition, western blot result outcomes confirmed, as expected, that LPS significantly activated phosphorylation of p44/42 extracellular regulated protein kinases (ERK1/2) and NF-κB. Unexpectedly, this effect was reversed by adding quercetin. To complement western blot results, we assessed p-ERK1/2 and p-p65 protein expression using immunofluorescence, which gave consistent results. Therefore, quercetin’s capacity to bar the TLR4-mediated NF-κB and MAPK signaling pathways may be the cause of its anti-inflammatory effects on LPS-induced inflammatory reactions in BREC. According to these results, quercetin may be utilized as an anti-inflammatory medication to alleviate inflammation brought on by high-grain feed, and it also lays out a conceptual foundation regarding the development and utilization of quercetin in the later stage.
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Shorobi, Fauzia Mahanaz, Fatema Yasmin Nisa, Srabonti Saha, Muhammad Abid Hasan Chowdhury, Mayuna Srisuphanunt, Kazi Helal Hossain e Md Atiar Rahman. "Quercetin: A Functional Food-Flavonoid Incredibly Attenuates Emerging and Re-Emerging Viral Infections through Immunomodulatory Actions". Molecules 28, n.º 3 (17 de janeiro de 2023): 938. http://dx.doi.org/10.3390/molecules28030938.
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Many of the medicinally active molecules in the flavonoid class of phytochemicals are being researched for their potential antiviral activity against various DNA and RNA viruses. Quercetin is a flavonoid that can be found in a variety of foods, including fruits and vegetables. It has been reported to be effective against a variety of viruses. This review, therefore, deciphered the mechanistic of how Quercetin works against some of the deadliest viruses, such as influenza A, Hepatitis C, Dengue type 2 and Ebola virus, which cause frequent outbreaks worldwide and result in significant morbidity and mortality in humans through epidemics or pandemics. All those have an alarming impact on both human health and the global and national economies. The review extended computing the Quercetin-contained natural recourse and its modes of action in different experimental approaches leading to antiviral actions. The gap in effective treatment emphasizes the necessity of a search for new effective antiviral compounds. Quercetin shows potential antiviral activity and inhibits it by targeting viral infections at multiple stages. The suppression of viral neuraminidase, proteases and DNA/RNA polymerases and the alteration of many viral proteins as well as their immunomodulation are the main molecular mechanisms of Quercetin’s antiviral activities. Nonetheless, the huge potential of Quercetin and its extensive use is inadequately approached as a therapeutic for emerging and re-emerging viral infections. Therefore, this review enumerated the food-functioned Quercetin source, the modes of action of Quercetin for antiviral effects and made insights on the mechanism-based antiviral action of Quercetin.
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Gröber, Uwe. "Quercetin". Zeitschrift für Orthomolekulare Medizin 9, n.º 03 (setembro de 2011): 21–22. http://dx.doi.org/10.1055/s-0031-1280225.
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BAUMANN, LESLIE S. "Quercetin". Skin & Allergy News 36, n.º 1 (janeiro de 2005): 18–19. http://dx.doi.org/10.1016/s0037-6337(05)70165-0.
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Jiyun, L., Z. Tai e S. J. Hopkins. "Quercetin". Drugs of the Future 22, n.º 7 (1997): 720. http://dx.doi.org/10.1358/dof.1997.022.07.414582.
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Edo, Yukako, Amane Otaki e Kazuhito Asano. "Quercetin Enhances the Thioredoxin Production of Nasal Epithelial Cells In Vitro and In Vivo". Medicines 5, n.º 4 (21 de novembro de 2018): 124. http://dx.doi.org/10.3390/medicines5040124.
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Background: Thioredoxin (TRX) acts as both a scavenger of reactive oxygen species (ROS) and an immuno-modulator. Although quercetin has been shown to favorably modify allergic rhinitis (AR) symptoms, its influence on TRX production is not well defined. The present study was designed to examine whether quercetin could favorably modify AR symptoms via the TRX production of nasal epithelial cells in vitro and in vivo. Methods: Human nasal epithelial cells (HNEpCs) were stimulated with H2O2 in the presence of quercetin. TRX levels in 24-h culture supernatants were examined with ELISA. BALB/c male mice were intraperitoneally sensitized to ovalbumin (OVA) and intranasally challenged with OVA every other day, beginning seven days after the final sensitization. The mice were orally administered quercetin once a day for five consecutive days, beginning seven days after the final sensitization. Nasal symptoms were assessed by counting the number of sneezes and nasal rubbing behaviors during a 10-min period immediately after the challenge. TRX levels in nasal lavage fluids obtained 6 h after the challenge were examined by ELISA. Results: Treatment with 1.0 nM quercetin increased H2O2-induced TRX levels. The oral administration of 20.0 mg/kg of quercetin significantly inhibited nasal symptoms after the challenge. The same dose of quercetin significantly increased TRX levels in nasal lavage fluids. Conclusions: Quercetin’s ability to increase TRX production may account, at least in part, for its clinical efficacy toward AR.
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Cordeiro, Maria Elvira Ribeiro, Flávio Klinpovous Kerppers, Luiza Ferreira Cunha, Ketllin Bragnholo, Luana Rodrigues Vasconcelos, Andressa Panegalli Hosni, Ivo Ilvan Kerppers et al. "Quercetin action on pain modulation/ Ação da quercetina sobre a modulação da dor". Brazilian Journal of Development 7, n.º 4 (30 de abril de 2021): 43616–34. http://dx.doi.org/10.34117/bjdv7n4-697.
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Background: Quercetin is a flavonoid widely found in plant kingdom and target of studies in pharmacological area due to its potent antinociceptive effect compared to analgesics used in conventional therapies. The aim was to evaluate its antinociceptive activity and antinociception mechanism. Methods: For this, 40 Norvegicus Wistar rats were used, divided into 4 groups: Q50 (treated with quercetin 50 mg/Kg), Q100 (treated with quercetin 100 mg/Kg), Q500 (treated with quercetin 500 mg/Kg) and Positive control (PC) without quercetin treatment), who were submitted through the pain induction methods by tail immersion and formalin in the first step to assess antinociceptive action and in the second step, tail immersion method receiving antagonists from opioid, cholinergic and nitric oxide - L-arginine to evaluate the action mechanism. Results: Quercetin antinociceptive activity was verified at the dose of 50 mg/kg and 100 mg/kg in tail immersion test after formalin injection, with better performance at the dose of 50 mg/kg. There were no statistically significant results in paw opening and capsaicin tests. Quercetin demonstrated a possible influence on opioid and cholinergic pathway, which was not observed on the nitric acid - L-arginine pathway in view of parameters tested. Conclusion: Quercetin performed the best antinociceptive activity at a dose 50 mg/kg and there was a possible influence on opioid and cholinergic pathways.
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Sethi, Gautam, Prangya Rath, Abhishek Chauhan, Anuj Ranjan, Renuka Choudhary, Seema Ramniwas, Katrin Sak, Diwakar Aggarwal, Isha Rani e Hardeep Singh Tuli. "Apoptotic Mechanisms of Quercetin in Liver Cancer: Recent Trends and Advancements". Pharmaceutics 15, n.º 2 (20 de fevereiro de 2023): 712. http://dx.doi.org/10.3390/pharmaceutics15020712.
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Due to rising incidence rates of liver cancer and worries about the toxicity of current chemotherapeutic medicines, the hunt for further alternative methods to treat this malignancy has escalated. Compared to chemotherapy, quercetin, a flavonoid, is relatively less harmful to normal cells and is regarded as an excellent free-radical scavenger. Apoptotic cell death of cancer cells caused by quercetin has been demonstrated by many prior studies. It is present in many fruits, vegetables, and herbs. Quercetin targets apoptosis, by upregulating Bax, caspase-3, and p21 while downregulating Akt, PLK-1, cyclin-B1, cyclin-A, CDC-2, CDK-2, and Bcl-2. Additionally, it has been reported to increase STAT3 protein degradation in liver cancer cells while decreasing STAT3 activation. Quercetin has a potential future in chemoprevention, based on substantial research on its anticancer effects. The current review discusses quercetin’s mechanisms of action, nanodelivery strategies, and other potential cellular effects in liver cancer.
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Aliaga, Carolina, e Eduardo A. Lissi. "Comparison of the free radical scavenger activities of quercetin and rutin An experimental and theoretical study". Canadian Journal of Chemistry 82, n.º 12 (1 de dezembro de 2004): 1668–73. http://dx.doi.org/10.1139/v04-151.
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Natural radical scavengers have recently received considerable interest owing to the role of free radicals in causing oxidative stress in living organisms. Flavonoids constitute one of the most important families of molecules with antioxidant activities, a characteristic associated with the presence in their structure of hydroxyl groups bound to aromatic rings. Quercetin is a potent antioxidant whose high reactivity could be associated with the presence of the OH group in the C ring. To address the role of this group in quercetin's free radical scavenging capacity, we have carried out experimental determinations and theoretical calculations regarding the reactivity of quercetin and rutin. The reactivity of both compounds towards free radicals was assessed employing the radical anion 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) and peroxyl radicals. These measurements indicate that quercetin is more reactive and has more reactive centers than rutin, suggesting that the extra OH group located in the C ring could directly contribute to reactivity of quercetin. This conclusion is in agreement with the evaluation of local reactivity indexes, such as the Fukui function.Key words: quercetin, rutin, antioxidant activity, ABTS, peroxyl radicals, Fukui function, local reactivity index.
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Shao, Zehua, Ran Li, Dongxing Shao, Hao Tang e Yu Han. "Albumin-Based Zn (II)-Quercetin Enzyme Mimic Scavenging ROS for Protection against Cardiotoxicity Induced by Doxorubicin". Pharmaceuticals 15, n.º 12 (8 de dezembro de 2022): 1524. http://dx.doi.org/10.3390/ph15121524.
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Doxorubicin (DOX) is a chemotherapeutic agent that can cause cardiotoxicity leading to progressive, chronic, life-threatening cardiomyopathy, called DOX-induced cardiomyopathy (DIC). DIC is a fatal cardiomyopathy with a worse prognosis compared to other cardiomyopathies and limits the use of DOX in malignancies due to its cardiotoxicity. DIC has been proven to be associated with reactive oxygen species (ROS)-induced side effect damage in cardiac myocytes. Currently, scavenging of reactive oxygen species is a practical strategy to reduce chemotherapy-associated DIC. Although quercetin has already been reported to have superior antioxidant activity, its clinical application is severely limited due to its rapid degradation and poor tissue absorption. Herein, we reported the preparation of a novel enzyme mimic via coordinated albumin, Zinc Ion (Zn2+) and quercetin. The enzyme mimics were capable of simultaneously increasing the biocompatibility and efficiently overcame the drawbacks of free quercetin, and were achieved by long circulation in vivo. Most importantly, these quercetin-based enzyme mimics had no effect on the antioxidant activity of quercetin. These beneficial therapeutic properties, together with high drug-carrying capacity and redox stimuli, will significantly improve quercetin’s alleviation of chemotherapeutic cardiotoxicity without causing significant side effects. Therefore, nanoparticles of albumin-based Zn (II)-Quercetin have a promising clinical application as an effective agent for mitigating the cardiotoxicity of chemotherapy.
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Fang, Yanni, Wenwen Jin, Zhen Guo e Jumei Hao. "Quercetin Alleviates Asthma-Induced Airway Inflammation and Remodeling through Downregulating Periostin via Blocking TGF‐β1/Smad Pathway". Pharmacology 108, n.º 5 (2023): 432–43. http://dx.doi.org/10.1159/000530703.
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<b><i>Introduction:</i></b> The aim of the study was to discuss whether the anti-asthmatic effect of quercetin is related to periostin and the downstream molecular pathway of quercetin’s anti-asthmatic effect. <b><i>Methods:</i></b> We constructed asthmatic mice, sensitized by ovalbumin, and administrated different treatments into mice according to the experimental design. In this study, we mainly observed the inflammatory response, airway fibrosis, and airway hyperresponsiveness in asthmatic mice. Pathological stains (H&E, PAS, and Masson) were performed. We also detected the inflammation factors and fibrosis-related cytokines by enzyme-linked immunosorbent serologic assay. In addition, we also explored the level of periostin by enzyme-linked immunosorbent serologic assay and Western blot. At the same time, TGF‐β1/Smad pathway was also determined by Western blot. <b><i>Results:</i></b> A high expression of periostin was found in asthmatic mice, and quercetin decreases periostin content in bronchoalveolar lavage fluid. Quercetin and OC-20 inhibit airway inflammation response, airway fibrosis, and airway hyperreactivity. Quercetin downregulated TGF‐β1/Smad pathway in the lung tissues of asthmatic mice. Anti-asthma role of quercetin is related to periostin. Then deeper mechanical study revealed that inhibiting TGF-β1 could improve asthmatic symptoms, and quercetin exerted the protective effect on asthmatic mice through inhibition of TGF‐β1/Smad pathway. <b><i>Conclusion:</i></b> Quercetin provided a protective role against asthma via periostin, manifested by mild inflammatory infiltration, reduced goblet cell proliferation, and reduced airway fibrosis. TGF‐β1/Smad pathway is an important transduction system, participating in the protective effect of quercetin on asthma.
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Aswathy, JM, Greeshma Murukan, Bosco Lawarence e K. Murugan. "DIFFERENTIAL EFFECT OF PURIFIED QUERCETIN AND ITS DERIVATIVES FROM IN VITRO CELL SUSPENSION CULTURES OF CAESALPINIA PULCHERRIMA SW. AGAINST SELECTED CANCER CELL LINES AND ITS MODE OF ACTION". Journal of Drug Delivery and Therapeutics 8, n.º 5-s (15 de outubro de 2018): 196–208. http://dx.doi.org/10.22270/jddt.v8i5-s.1950.
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Tribal people use the floral extract of Caesalpinia pulcherrima to cure liver, stomach and skin prone disorders in traditional Indian medicine. This study aimed to evaluate the effect of purified quercetin and its derivatives from in vitro cell suspension cultures of C. pulcherrima Sw. against SW 480, HeLa, MCF-7 and MCF 10A cell lines and its mode of action. Standard protocol was developed for callus induction using leaf explants. Cytotoxic effect was evaluated against SW 480, HeLa, MCF-7 and MCF 10A cells by MTT assay. Apoptosis was evaluated via Hoechst analysis, flow cytometry, mitochondrial membrane potential and caspase 3 and 9 expression. 2, 4-D (2.5 mg/l), BAP (2.5 mg/l) + kin (1 mg/ml) was effective for remarkable callus induction. Further, cell suspension culture was established. Effect of elicitors on cell suspension culture was also carried. Sucrose, ABA and salicylic acid (SA) at different concentrations influenced cell biomass and quercetin synthesis. Cells cultured on the medium fortified with 45 g/L sucrose without ABA/SA showed the highest quercetin content (16.5 mg/g). Quercetin was purified, fractionated by HPLC-DAD and was further analyzed by NMR revealed a major fraction of quercetin (3, 5, 7, 3’, 4’-pentahydroxyflavon). Insignificant cytotoxicity was noticed in SW 480, HeLa, MCF 10A when compared to MCF-7 cell lines exposed to different concentrations of purified quercetin for 24- 48 h. Similarly, the apoptosis by nuclei staining using Hoechst 33258 revealed a concentration dependent effect on MCF 7 cells only. This was further substantiated by caspase-9 and 3 induction and mitochondrial depolarization as revealed by flow cytometry. Overall, the results showed that quercetin and its derivatives induced effective apoptosis on MCF-7 cells. Quercetin isolated from the in vitro cell suspension culture of C. pulcherrima showed significant cytotoxicity and apoptotic activity towards MCF-7 cell lines as compared to other cell lines.
Keywords: Caesalpinia pulcherrima; quercetins; suspension culture; cytotoxicity; apoptotic.
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Abdul-Qader, Ziena M., Kareem M. Rabie e Huda S. Husni. "Efficacy of Bio-fertilizer and Chemical Fertilization on Flavonoids Distribution in Different Plant Parts of Stevia rebaudiana (Bertoni.)". Bionatura 7, n.º 2 (15 de maio de 2022): 1–9. http://dx.doi.org/10.21931/rb/2022.07.02.20.
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This study aims to investigate the effect of the biological and chemical fertilizers on the content of the flavonoid compounds distributed within the different plant parts (leaves, stems, branches, and roots) of Stevia rebaudiana (Bertoni.) grown in Iraq. The results showed that the treatments of the biological fertilizers, including Mycorrhiza (C2) achieved the highest content of the most flavonoids in different parts of the plant. The treatment C2 recorded a rise of the flavonoid compounds Naringin, Naringenin and Luteolin 7-glucose in the leaves, Naringin, Rutin, and Acacetin7-neorutinoside in the stems and branches, and Apiening6-rhamnose8- glucose, Apigenin7-o neohespiroside, Kampferol3-7dirmmoside, Quercetrin, Narengenin, Acacetin7-neorutinoside, Kampferol, and Luteolin 7-glucose in the roots. On the other hand, treatment C1 recorded the highest content of Quercetin in the leaves, Quercetrin3-O glucose in the stems and branches, and Quercetrin3-O glucose, Naringenin, and Acacetin7-neorutinoside in the leaves . Keywords. Flavonoid, Stevia, Mycorrhiza and chemical Fertilization
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Fernández-Calvet, Ariadna, Begoña Euba, Lucía Caballero, Roberto Díez-Martínez, Margarita Menéndez, Carlos Ortiz de Solórzano, José Leiva, Vicente Micol, Enrique Barrajón-Catalán e Junkal Garmendia. "Preclinical Evaluation of the Antimicrobial-Immunomodulatory Dual Action of Xenohormetic Molecules against Haemophilus influenzae Respiratory Infection". Biomolecules 9, n.º 12 (17 de dezembro de 2019): 891. http://dx.doi.org/10.3390/biom9120891.
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Chronic obstructive pulmonary disease (COPD) is characterized by abnormal inflammation and impaired airway immunity, providing an opportunistic platform for nontypeable Haemophilus influenzae (NTHi) infection. In this context, therapies targeting not only overactive inflammation without significant adverse effects, but also infection are of interest. Increasing evidence suggests that polyphenols, plant secondary metabolites with anti-inflammatory and antimicrobial properties, may be protective. Here, a Cistus salviifolius plant extract containing quercetin, myricetin, and punicalagin was shown to reduce NTHi viability. Analysis of these polyphenols revealed that quercetin has a bactericidal effect on NTHi, does not display synergies, and that bacteria do not seem to develop resistance. Moreover, quercetin lowered NTHi airway epithelial invasion through a mechanism likely involving inhibition of Akt phosphorylation, and reduced the expression of bacterially-induced proinflammatory markers il-8, cxcl-1, il-6, pde4b, and tnfα. We further tested quercetin’s effect on NTHi murine pulmonary infection, showing a moderate reduction in bacterial counts and significantly reduced expression of proinflammatory genes, compared to untreated mice. Quercetin administration during NTHi infection on a zebrafish septicemia infection model system showed a bacterial clearing effect without signs of host toxicity. In conclusion, this study highlights the therapeutic potential of the xenohormetic molecule quercetin against NTHi infection.
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Rocha-Brito, Karin J. P., Stefano Piatto Clerici, Helon Guimarães Cordeiro, Amanda Petrina Scotá Ferreira, Emanuella Maria Barreto Fonseca, Paola R. Gonçalves, Júlia Laura F. Abrantes et al. "Quercetin increases mitochondrial proteins (VDAC and SDH) and downmodulates AXL and PIM-1 tyrosine kinase receptors in NRAS melanoma cells". Biological Chemistry 403, n.º 3 (3 de dezembro de 2021): 293–303. http://dx.doi.org/10.1515/hsz-2021-0261.
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Abstract Melanoma is a type of skin cancer with low survival rates after it has metastasized. In order to find molecular differences that could represent targets of quercetin in anti-melanoma activity, we have chosen SKMEL-103 and SKMEL-28 melanoma cells and human melanocytes as models. Firstly, we observed that quercetin was able in reducing SKMEL-103 cell viability, but not in SKMEL-28. Besides that, quercetin treatment caused inhibition of AXL in both cell lines, but upregulation of PIM-1 in SKMEL-28 and downregulation in SKMEL-103. Moreover, HIF-1 alpha expression decreased in both cell lines. Interestingly, quercetin was more effective against SKMEL-103 than kinases inhibitors, such as Imatinib, Temsirolimus, U0126, and Erlotinib. Interestingly, we observed that while the levels of succinate dehydrogenase and voltage-dependent anion channel increased in SKMEL-103, both proteins were downregulated in SKMEL-28 after quercetin’s treatment. Furthermore, AKT, AXL, PIM-1, ABL kinases were much more active and chaperones HSP90, HSP70 and GAPDH were highly expressed in SKMEL-103 cells in comparison with melanocytes. Our findings indicate, for the first time, that the efficacy of quercetin to kill melanoma cells depends on its ability in inhibiting tyrosine kinase and upregulating mitochondrial proteins, at least when SKMEL-103 and SKMEL-28 cells response were compared.
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Tronina, Tomasz, Mateusz Łużny, Monika Dymarska, Monika Urbaniak, Ewa Kozłowska, Michał Piegza, Łukasz Stępień e Tomasz Janeczko. "Glycosylation of Quercetin by Selected Entomopathogenic Filamentous Fungi and Prediction of Its Products’ Bioactivity". International Journal of Molecular Sciences 24, n.º 14 (24 de julho de 2023): 11857. http://dx.doi.org/10.3390/ijms241411857.
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Quercetin is the most abundant flavonoid in food products, including berries, apples, cauliflower, tea, cabbage, nuts, onions, red wine and fruit juices. It exhibits various biological activities and is used for medical applications, such as treating allergic, inflammatory and metabolic disorders, ophthalmic and cardiovascular diseases, and arthritis. However, its low water solubility may limit quercetin’s therapeutic potential. One method of increasing the solubility of active compounds is their coupling to polar molecules, such as sugars. The attachment of a glucose unit impacts the stability and solubility of flavonoids and often determines their bioavailability and bioactivity. Entomopathogenic fungi are biocatalysts well known for their ability to attach glucose and its 4-O-methyl derivative to bioactive compounds, including flavonoids. We investigated the ability of cultures of entomopathogenic fungi belonging to Beauveria, Isaria, Metapochonia, Lecanicillium and Metarhizium genera to biotransform quercetin. Three major glycosylation products were detected: (1), 7-O-β-D-(4″-O-methylglucopyranosyl)-quercetin, (2) 3-O-β-D-(4″-O-methylglucopyranosyl)-quercetin and (3) 3-O-β-D-(glucopyranosyl)-quercetin. The results show evident variability of the biotransformation process, both between strains of the tested biocatalysts from different species and between strains of the same species. Pharmacokinetic and pharmacodynamic properties of the obtained compounds were predicted with the use of cheminformatics tools. The study showed that the obtained compounds may have applications as effective modulators of intestinal flora and may be stronger hepato-, cardio- and vasoprotectants and free radical scavengers than quercetin.