Research - Quercetin
Suppression of neuropeptide production by quercetin in allergic rhinitis model rats
- Misako Kashiwabara,
- Kazuhito Asano
- Tomomi Mizuyoshi and
- Hitome Kobayashi
Quercetin, a dietary flavonoid found in many fruits, red wine and onion, among others, has been reported to have potent anti-oxidant, anti-viral and anti-cancer effects. Although quercetin is also reported to have anti-inflammatory and anti-allergic effects, the precise mechanisms by which quercetin favorably modify the clinical conditions of allergic diseases such as allergic rhinitis (AR). The present study was designed to examine the influence of quercetin on the development of AR by using AR model rats.
Sprague-Dawley (SD) rats were sensitized with toluene 2,4-diisocyanate (TDI) by intranasal instillation of a 10 % TDI in ethyl acetate in a volume of 5 μl once a day for 5 consecutive days. This sensitization procedure was repeated after a 2-day interval. After 5 days of the second sensitization, rats were treated with various doses of quercetin once a day for 2 to 7 days. Nasal allergy-like symptoms, which were induced by bilateral application of 5 μl of 10 % TDI in ethyl acetate, were assessed by counting sneezing and nasal rubbing behaviors for 10 min just after TDI nasal challenge. The levels of substance P (SP), calcitonin gene-related peptide (CGRP) and nerve growth factor (NGF) in nasal lavage fluids obtained 6 h after TDI nasal challenge was examined by ELISA.
Oral administration of quercetin for 5 and 7 days, but not 2 and 3 days, could inhibit sneezing and nasal rubbing movements, which were increased by TDI nasal challenge. The minimum dose that caused significant inhibition was 25 mg/kg. Oral administration of quercetin at more than 25 mg/kg for 5 days significantly inhibited the increase in SP, CGRP and NGF contents in nasal lavage fluids induced by TDI nasal challenge.
The present results strongly suggested that quercetin will be a good candidate for the supplement on the management and treatment of allergic diseases, especially AR.
Source : BMC Complementary and Alternative Medicine
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Effects of a quercetin-rich onion skin extract on 24 h ambulatory blood pressure and endothelial function in overweight-to-obese patients with (pre-)hypertension: a randomised double-blinded placebo-controlled cross-over trial
Verena Brülla1, Constanze Buraka1, Birgit Stoffel-Wagnera2, Siegfried Wolfframa3, Georg Nickeniga4, Cornelius Müllera4, Peter Langgutha5, Birgit Altehelda1, Rolf Fimmersa6, Stefanie Naafa7, Benno F. Zimmermanna7a8, Peter Stehlea1 and Sarah Egerta1 c1
a1 Department of Nutrition and Food Sciences, Nutritional Physiology, University of Bonn, 53115 Bonn, Germany
a2 Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital Bonn, 53127 Bonn, Germany
a3 Institute of Animal Nutrition and Physiology, Christian-Albrechts-University Kiel, 24118 Kiel, Germany
a4 Department of Cardiology, Angiology and Pneumology, University Hospital Bonn, 53127 Bonn, Germany
a5 Department of Biopharmaceutics and Pharmaceutical Technology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University Mainz, 55099 Mainz, Germany
a6 Institute of Medical Biometry, Informatics and Epidemiology, University Hospital Bonn, 53127 Bonn, Germany
a7 Institut Prof. Dr. Georg Kurz GmbH, 50933 Köln, Germany
a8 Department of Nutrition and Food Sciences, Food Technology and Biotechnology, University of Bonn, 53117 Bonn, Germany
The polyphenol quercetin may prevent CVD due to its antihypertensive and vasorelaxant properties. We investigated the effects of quercetin after regular intake on blood pressure (BP) in overweight-to-obese patients with pre-hypertension and stage I hypertension. In addition, the potential mechanisms responsible for the hypothesised effect of quercetin on BP were explored. Subjects (n 70) were randomised to receive 162 mg/d quercetin from onion skin extract powder or placebo in a double-blinded, placebo-controlled cross-over trial with 6-week treatment periods separated by a 6-week washout period. Before and after the intervention, ambulatory blood pressure (ABP) and office BP were measured; urine and blood samples were collected; and endothelial function was measured by EndoPAT technology. In the total group, quercetin did not significantly affect 24 h ABP parameters and office BP. In the subgroup of hypertensives, quercetin decreased 24 h systolic BP by −3·6 mmHg (P=0·022) when compared with placebo (mean treatment difference, −3·9 mmHg; P=0·049). In addition, quercetin significantly decreased day-time and night-time systolic BP in hypertensives, but without a significant effect in inter-group comparison. In the total group and also in the subgroup of hypertensives, vasoactive biomarkers including endothelin-1, soluble endothelial-derived adhesion molecules, asymmetric dimethylarginine, angiotensin-converting enzyme activity, endothelial function, parameters of oxidation, inflammation, lipid and glucose metabolism were not affected by quercetin. In conclusion, supplementation with 162 mg/d quercetin from onion skin extract lowers ABP in patients with hypertension, suggesting a cardioprotective effect of quercetin. The mechanisms responsible for the BP-lowering effect remain unclear.
Source : British Journal of Nutrition
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Protective effect of polyphenols in an inflammatory process associated with experimental pulmonary fibrosis in mice
Polyphenols have been described to have a wide range of biological activities, and many reports, published during recent years, have highlighted the beneficial effects of phenolic compounds, illustrating their promising role as therapeutic tools in several acute and chronic disorders. The purpose of study was to evaluate, in an already-assessed model of lung injury caused by bleomycin (BLM) administration, the role of resveratrol and quercetin, as well as to explore the potential beneficial properties of a mango leaf extract, rich in mangiferin, and a grape leaf extract, rich in dihydroquercetin (DHQ), on the same model. Mice were subjected to intra-tracheal administration of BLM, and polyphenols were administered by oral route immediately after BLM instillation and daily for 7 d. Treatment with resveratrol, mangiferin, quercetin and DHQ inhibited oedema formation and body weight loss, as well as ameliorated polymorphonuclear infiltration into the lung tissue and reduced the number of inflammatory cells in bronchoalveolar lavage fluid. Moreover, polyphenols suppressed inducible nitric oxide synthase expression, and prevented oxidative and nitroxidative lung injury, as shown by the reduced nitrotyrosine and poly (ADP-ribose) polymerase levels. The degree of apoptosis, as evaluated by Bid and Bcl-2 balance, was also suppressed after polyphenol treatment. Finally, these natural products down-regulated cyclo-oxygenase-2, extracellular signal-regulated kinase phosphorylated expression and reduced NF-κBp65 translocation. Our findings confirmed the anti-inflammatory effects of resveratrol and quercetin in BLM-induced lung damage, and highlight, for the first time, the protective properties of exogenous administration of mangiferin and DHQ on experimental pulmonary fibrosis.
Source : British Journal of Nutrition
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Epicatechin and Quercetin Affects Some Biomarkers of Endothelial Dysfunction and Inflammation in (Pre)Hypertensive Adults: A Randomized Double-Blind, Placebo-Controlled, Crossover Trial1,2
James I Dower3,4, Johanna M Geleijnse3,4, Lieke Gijsbers3,4,Casper Schalkwijk3,5, Daan Kromhout4, and Peter C Hollman3,4,*
Background: Consumption of flavonoid-rich foods such as cocoa and tea may reduce cardiovascular disease risk. The flavonoids epicatechin (in cocoa and tea) and quercetin (in tea) probably play a role by reducing endothelial dysfunction and inflammation, 2 main determinants of atherosclerosis.
Objective: We studied the effects of supplementation of pure epicatechin and quercetin on biomarkers of endothelial dysfunction and inflammation.
Methods: Thirty-seven apparently healthy (pre)hypertensive men and women (40–80 y) participated in a randomized, double-blind, placebo-controlled crossover trial. Participants ingested (-)-epicatechin (100 mg/d), quercetin-3-glucoside (160 mg/d), or placebo capsules for a period of 4 wk, in random order. Plasma biomarkers of endothelial dysfunction and inflammation were measured at the start and end of each 4-wk intervention period. The differences in changes over time between the intervention and placebo periods (Δintervention − Δplacebo) were calculated and tested with a linear mixed model for repeated measures.
Results: Epicatechin changed Δepicatechin − Δplacebo for soluble endothelial selectin (sE-selectin) by −7.7 ng/mL (95% CI: −14.5, −0.83; P = 0.03) but did not significantly change this difference (−0.30; 95% CI: −0.61, 0.01; P = 0.06) for thez score for endothelial dysfunction. Quercetin changed Δquercetin − Δplacebo for sE-selectin by −7.4 ng/mL (95% CI: −14.3, −0.56; P = 0.03), that for IL-1β by −0.23 pg/mL (95% CI: −0.40, −0.06; P = 0.009), and that for the z score for inflammation by −0.33 (95% CI: −0.60, −0.05; P = 0.02).
Conclusions: In (pre)hypertensive men and women, epicatechin may contribute to the cardioprotective effects of cocoa and tea through improvements in endothelial function. Quercetin may contribute to the cardioprotective effects of tea possibly by improving endothelial function and reducing inflammation.
Source : Journal Nutrition
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Preliminary Study of Quercetin Affecting the Hypothalamic-Pituitary-Gonadal Axis on Rat Endometriosis Model
Yang Cao,1 Meng-fei Zhuang,1 Ying Yang,2 Shu-wu Xie,3 Jin-gang Cui,1 Lin Cao,3 Ting-ting Zhang,1 and Yan Zhu3
1Department of Obstetrics and Gynecology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China
2Department of Traditional Chinese Medicine, The First People’s Hospital of Yinchuan, Ningxia 750001, China
3Department of Reproductive Pharmacology, NPFPC Key Laboratory of Contraceptives and Devices, Shanghai Institute of Planned Parenthood Research, Shanghai 200032, China
In this study, the endometriosis rats model was randomly divided into 6 groups: model control group, ovariectomized group, Gestrinone group, and quercetin high/medium/low dose group. Rats were killed after 3 weeks of administration. The expression levels of serum FSH and LH were detected by ELISA. The localizations and quantities of ERα, ERβ, and PR were detected by immunohistochemistry and western blot. The results showed that the mechanism of quercetin inhibiting the growth of ectopic endometrium on rat endometriosis model may be through the decreasing of serum FSH and LH levels and then reducing local estrogen content to make the ectopic endometrium atrophy. Quercetin can decrease the expression of ERα, ERβ, and PR in hypothalamus, pituitary, and endometrium, thereby inhibiting estrogen and progesterone binding to their receptors to play the role of antiestrogen and progesterone.
According to the above results, the mechanism of quercetin inhibiting the growth of ectopic endometrium in rat model is that quercetin can be combined with the receptor ERα of the HPGA axis, feedback inhibits the release of GnRH, and exerts its antigonadotropic activity to inhibit the secretion of FSH and LH and to reduce the level of serum E2, causing the deficiency of hormone supplement in ectopic endometrium, thus reducing the height of endometrial epithelial layer and the number of ectopic endometrial glands, eventually leading to the atrophy of ectopic endometrial epithelial. However, in summary, ER and PR distributed in the reproductive system and the central nervous system play different roles, and how quercetin regulates their expression and changes the downstream pathways related with ER and PR is worthy of future study.
Source ; Journal Evidence Based Complementary and Alternative Medicine
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A targeted approach for evaluating preclinical activity of botanical extracts for support of bone health
Yumei Lina1, Mary A. Murraya1, I. Ross Garretta2a3, Gloria E. Gutierreza2a4, Jeffry S. Nymana2a5, Gregory Mundya2a6 †, David Fasta7, Kevin W. Gellenbecka1 c1, Amitabh Chandraa7 and Shyam Ramakrishnana1a8
a1 Nutrilite Health Institute, 5600 Beach Boulevard, Buena Park, CA 90622, USA
a2 OsteoScreen Ltd, 2040 Babcock Road, San Antonio, TX 78023, USA
a3 9909 Charthouse Cove, Austin, TX 78730, USA
a4 Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA
a5 Department of Orthopaedic Surgery and Rehabilitation, Vanderbilt University Medical Center, Nashville, TN 37232, USA
a6 Vanderbilt University Medical Center, Nashville, TN 37232, USA
a7 Access Business Group, 7575 East Fulton Avenue, Ada, MI 49355, USA
a8 The Himalaya Drug Company, Makali, Tumkur Road, Bangalore – 562123, India
Using a sequential in vitro/in vivo approach, we tested the ability of botanical extracts to influence biomarkers associated with bone resorption and bone formation. Pomegranate fruit and grape seed extracts were found to exhibit anti-resorptive activity by inhibiting receptor activator of nuclear factor-κB ligand (RANKL) expression in MG-63 cells and to reduce IL-1β-stimulated calvarial 45Ca loss. A combination of pomegranate fruit and grape seed extracts were shown to be effective at inhibiting bone loss in ovariectomised rats as demonstrated by standard histomorphometry, biomechanical and bone mineral density measurements. Quercetin and licorice extract exhibited bone formation activity as measured by bone morphogenetic protein-2 (BMP-2) promoter activation, increased expression of BMP-2 mRNA and protein levels, and promotion of bone growth in cultured mouse calvariae. A combination of quercetin and licorice extract demonstrated a potential for increasing bone mineral density in an intact female rat model as compared with controls. The results from this sequential in vitro/in vivo research model yielded botanical extract formulas that demonstrate significant potential benefits for bone health.
Source : The Journal of Nutritional Sciences
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QUERCETIN ALLEVIATES BISPHENOL A-INDUCED CHANGES IN NUCLEIC ACID AND PROTEIN CONTENTS IN MICE
NEHA P. SANGAI and RAMTEJ J. VERMA*
Department of Zoology, University School of Sciences, Gujarat University, Ahmedabad-380 009, Gujarat, India
The present study was an attempt to examine toxic effects of bisphenol A in liver and kidney of mice and its alleviation by quercetin. Oral administration of bisphenol A (60 and 120 mg/kg b. w./day) for 30 days caused, as compared to vehicle control significant, dose-dependent decrease in DNA, RNA and protein contents in liver and kidney of mice. Supplementation of quercetin (60 mg/kg b. w./day) along with bisphenol A
for 30 days caused, as compared to bisphenol A alone treated groups, significant alleviation in DNA, RNA and protein contents. The amelioration was comparatively higher for high dose bisphenol A plus quercetin treated group than that of low dose plus quercetin treated group.
....In conclusion, the present investigation has shown that bisphenol A is capable of producing alterations in biochemical parameters investigated in vital organs i.e., liver and kidney which are the organs responsible of detoxification of xenobiotics and foreign compounds. The alterations in biochemical parameters appeared to be more pronounced with the liver as compared to kidney. The 30 days treatment with bisphenol A revealed that bisphenol A might lead to DNA adduct formation with defect in RNA metabolism, which leads to impaired protein synthesis as DNA, RNA and protein contents decrease in case of bisphenol A treated animals Also, this study clarifies that the damage caused by plasticizer in mice can be recovered by combined treatment of quercetin and bisphenol A for 30 days. This may be attributed to the hepatoprotective, renoprotective
and antioxidative properties of quercetin.
Source : Acta Poloniae Pharmaceutica ñ Drug Research, Vol. 68 No. 6 pp. 867ñ873, 2011
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