• Korean Journal of Medicinal Crop Science
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• v.10 no.1
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• pp.12-16
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• 2002

Concentration of quercetin and soluble tannin in Houttuynia cordata were determined at different growth stages as well as plant parts and application amounts of compost. Both contents of quercetin and tannin at growth stages were decreased before flowering time but slightly increased after flowering. The both contents of components in Houttuynia cordata collected on April 20 were shown to be markedly increased compared to those collected in May or June. The contents of quercetin and tannin at different organs were the highest in the flower. In the experiment of application amounts of compost, as application amounts is increased, fresh weight of aerial part was increased but the contents of quercetin and tannin were decreased. The contents of quercetin and tannin were the highest with 0.67% and 2.3%, respectively, in the compost non-treatment.

• Journal of Embryo Transfer
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• v.29 no.2
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• pp.141-148
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• 2014

Quercetin and genistein, plentifully present in fruits and vegetables, are flavonoid family members that have antioxidative function and plant-derived phytoestrogen activity. The antioxidative effects of quercetin and genistein on boar sperm characteristics and in vitro development of IVF embryo were investigated. The sperm motility was increased by addition of genistein $50{\mu}M$ for 6 hr incubation compared to control (p<0.05). The sperm viability was increased by addition of quercetin 1 and $50{\mu}M$ and genestein 1 and $50{\mu}M$ for 3 hr incubation. In addition, the sperm viability seemed to be increased dose-dependantly by addition of quercetin or genistein 1 and $50{\mu}M$, respectively (p<0.05). The membrane integrities were not increased by quercetin or genistein treatments for 3 hr or 6 hr incubation period except for quercetin $1{\mu}M$ for 3 hr incubation. In mitochondrial activities, addition of quercetin $50{\mu}M$ for 6 hr incubation increased mitochondrial activity but decreased at $100{\mu}M$ concentration compared with control (p<0.05). When porcine IVF embryos were cultured in PZM-3 medium supplemented with low concentrations of quercetin ($1{\sim}10{\mu}M$), the developmental rates to morula and blastocyst increased but significantly decreased at high concentrations of quercetin ($25{\sim}50{\mu}M$). The highest developmental rate to blastocysts among all concentrations of quercetin was shown at quercetin $10{\mu}M$ (p<0.05). The developmental rates to morula or blastocysts at low ($0.01{\sim}1{\mu}M$) and high ($5{\sim}10{\mu}M$) concentrations of genistein were not significantly different among all treatment group and genistein did not affect on IVF embryo development. These results suggest that quercetin and genistein seem to have positive effects at certain concentrations on sperm characteristics such as motility, viability and mitochondrial activity. In addition, low concentrations of quercetin (1, 5 and $10{\mu}M$) in this experiment, seem to have beneficial effect on porcine IVF embryo development but genistein did not affect on it at all given concentrations ($0.01{\sim}10{\mu}M$).

• Journal of Life Science
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• v.21 no.3
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• pp.464-467
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• 2011

Quercetin is a major flavonoid present in onions, which acts as an antioxidant. Quercetin exists both as a free compound and conjugated with carbohydrates, primarily as glucosides in onion. Aged black onion was made through a 30 day aging process in which the onions were kept in an environment of $60^{\circ}C$ and high humidity (90% RH). Quercetin and quercetin glucosides were assayed in onion bulbs before and after the aging process, using high performance liquid chromatography-electrospray ion trap mass spectrometry (HPLC-ESI/MS/MS). Quercetin mono- and diglucosides were identified in fresh onion bulbs, whereas quercetin aglycone was the only form present in aged black onion bulbs. These findings indicate that the quercetin mono- and di-glucosides present in fresh onions undergo complete deglycosylation during the aging process. Such profiling will provide a rapid method that can be used to assess changes in the two major quercetin glycosides during the aging process of onion bulbs.

• Journal of Periodontal and Implant Science
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• v.43 no.4
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• pp.191-197
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• 2013

Purpose: Nitric oxide (NO) is a short-lived bioactive molecule that is known to play an important role in the pathogenesis of periodontal disease. In the current study, we investigated the effect of the flavonoid quercetin on the production of NO in murine macrophages activated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen related to inflammatory periodontal disease, and tried to elucidate the underlying mechanisms of action. Methods: LPS was isolated from P. intermedia ATCC 25611 cells by the standard hot phenol-water method. The concentration of NO in cell culture supernatants was determined by measuring the accumulation of nitrite. Inducible NO synthase (iNOS) and heme oxygenase-1 (HO-1) protein expression, phosphorylation of c-Jun N-terminal kinase (JNK) and p38, inhibitory ${\kappa}B$ $(I{\kappa}B)-{\alpha}$ degradation, and signal transducer and activator of transcription 1 (STAT1) phosphorylation were analyzed via immunoblotting. Results: Quercetin significantly attenuated iNOS-derived NO production in RAW246.7 cells activated by P. intermedia LPS. In addition, quercetin induced HO-1 protein expression in cells activated with P. intermedia LPS. Tin protoporphyrin IX (SnPP), a competitive inhibitor of HO-1, abolished the inhibitory effect of quercetin on LPS-induced NO production. Quercetin did not affect the phosphorylation of JNK and p38 induced by P. intermedia LPS. The degradation of $I{\kappa}B-{\alpha}$ induced by P. intermedia LPS was inhibited when the cells were treated with quercetin. Quercetin also inhibited LPS-induced STAT1 signaling. Conclusions: Quercetin significantly inhibits iNOS-derived NO production in murine macrophages activated by P. intermedia LPS via anti-inflammatory HO-1 induction and inhibition of the nuclear factor-${\kappa}B$ and STAT1 signaling pathways. Our study suggests that quercetin may contribute to the modulation of host-destructive responses mediated by NO and appears to have potential as a novel therapeutic agent for treating inflammatory periodontal disease.

• YAKHAK HOEJI
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• v.53 no.5
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• pp.235-240
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• 2009

The interaction of cadmium (II) ion with quercetin was investigated in aqueous solution at different pH. The quercetin/cadmium stochiometries for cadmium (II) binding have been determined by UV-vis spectrophotometric method. The complexation of Cd(II) ion with 54.72 ${\mu}M$ quercetin (A=1.00793) was formed in 0.2 M $NH_3-0.2$ M $NH_4Cl$ (pH 8.0) buffer solution. 1:1 Cd(II)-complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH when interacted with quercetin in buffer solution. These results suggest that Cd(II)-quercetin complex has the optimal condition of chelation in basic buffer solution.

• YAKHAK HOEJI
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• v.42 no.1
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• pp.59-69
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• 1998

To increase the solubility of quercetin, which is a practically insoluble flavonoid of Ginkgo biloba leaf, the effects of nonaqueous vehicles. Their cosolvents, water-sol uble polymers and modified cyclodextrins (CDs) were observed. Polyethylene glycols, diethyleneglycol monoethyl ether, and their cosolvents with water showed a good solvency toward quercetin. Also the aqueous solutions of povidone, copolyvidone and Cremophor RH 40 was effective in solubilizing quercetin. Complex formation of quercetin with ${\beta}$-cyclodextrin (${\beta}$-CD), dimethyl-${\beta}$-cyclodextiin (DMCD), 2-hydroxypropyl-${\beta}$-cyclodextrin (HPCD) and ${\beta}$-cyclodextrin sulfobutyl ether (SBCD) in water was investigated by solubility method at $37^{\circ}C$. The addition of CDs in water markedly increased the solubility of quercetin with increasing the concentration. AL type phase solubility diagrams were obtained with CDs studied. Solubilizaton efficiency by CDs was in the order of SBCD >> DMCD > HPCD > ${\beta}$-CD. The dissolution rates of quercetin from solid dispersions with copolyvidone, povidone and HPCD were much faster than those of drug alone and corresponding physical mixtures, and exceeded the equilibrium solubility (3.03${\pm}1.72{\mu}$g/ml). The permeation of quercetin through duodenal mucosa did not occur even in the presence of enhancers such as bile salts, but the permeation was observed when the mucus layer was scraped off. This was due to the fact that quercetin had a strong binding to mucin ($58.5{\mu}$g/mg mucin). However rutin was permeable to the duodenal mucosa. The addition of enhancer significantly increased the permeation of rutin in the order of sodium glycocholate.

• Journal of Life Science
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• v.19 no.10
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• pp.1444-1450
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• 2009

The number of patients with immune- mediated dermatitis such as contact dermatitis is increasing year by year. Allergic contact dermatitis is a complex phenomenon that involves resident epidermal cells, fibroblasts, and endothelial cells, as well as invading leukocytes that interact with each other under the control of a network of cytokines and lipid mediators. It is a cell-mediated immune reaction, which occurs after susceptible individuals are exposed to sensitizing chemicals, and characteristic eczematous reaction is seen at the point of contact with an allergen. In this study, we investigated the allergy prevention effects of quercetin on mast cell-mediated allergic inflammation in BALB/c mice. BALB/c mice were sensitized with 40 ${\mu}l$ of 1.5% picryl choloride (PCL) to the left and right ear each. Total serum IgE levels and histamine levels were measured by the sandwich ELISA method using mouse IgE, histamine measuring kit. For histopathological examination, paraffin sections were stained with hematoxylin and eosin(HE) or toluidine blue(TB). Ear swelling responses were much weaker in the high-dose group (100 mg/kg) than the control group (0 mg/kg). The number of mast cells showed a significant decrease in the high-dose group (100 mg/kg) compared to the control group (0 mg/kg). Degranulation of mast cells was also confirmed by Toluidine Blue (TB) staining method. Both total serum IgE and histamine levels were significantly decreased in the high-dose group (100 mg/kg) compared to other groups. These findings suggest a certain relationship between the elevation of IgE, histamine levels and the degranulation of mast cells. These results show that the pharmacological actions of quercetin indicate its potential activity for prevention of allergic inflammatory diseases through the down-regulation of mast cell activation.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.518-520
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• 2014

Hybrids of some natural compounds are promising to obtain new leads with good biological activities for drug discovery. Three quercetin aspirinates were synthesized by esterification of the 3-and 7-hydroxyl groups of quercetin with aspirin. Biological activities of these quercetin aspirinates were initially screened and showed better cytotoxic activities against tumor cell lines HL-60 and HepG2 and less scavenging activity against DPPH than the quercetin respectively.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.5
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• pp.279-283
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• 2011

Quercetin (3,3',4',5,7-pentahydroxyflavone) is an attractive therapeutic flavonoid for cancer treatment because of its beneficial properties including apoptotic, antioxidant, and antiproliferative effects on cancer cells. However, the exact mechanism of action of quercetin on ion channel modulation is poorly understood in bladder cancer 253J cells. In this study, we demonstrated that large conductance $Ca^{2+}$-activated $K^+$ ($BK_{Ca}$) or MaxiK channels were functionally expressed in 253J cells, and quercetin increased $BK_{Ca}$ current in a concentration dependent and reversible manner using a whole cell patch configuration. The half maximal activation concentration ($IC_{50}$) of quercetin was $45.5{\pm}7.2{\mu}m$. The quercetin-evoked $BK_{Ca}$ current was inhibited by tetraethylammonium (TEA; 5 mM) a non-specific $BK_{Ca}$ blocker and iberiotoxin (IBX; 100 nM) a $BK_{Ca}$-specific blocker. Quercetin-induced membrane hyperpolarization was measured by fluorescence-activated cell sorting (FACS) with voltage sensitive dye, bis (1,3-dibutylbarbituric acid) trimethine oxonol ($DiBAC_4$2(3); 100 nM). Quercetin-evoked hyperpolarization was prevented by TEA. Quercetin produced an antiproliferative effect ($30.3{\pm}13.5%$) which was recovered to $53.3{\pm}10.5%$ and $72.9{\pm}3.7%$ by TEA and IBX, respectively. Taken together our results indicate that activation of $BK_{Ca}$ channels may be considered an important target related to the action of quercetin on human bladder cancer cells.

• Korean Journal of Poultry Science
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• v.38 no.4
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• pp.265-273
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• 2011

This study was carried out to determine the effect of dietary supplementation of quercetin and methoxylated quercetin extracted from onions on chicken thigh meat quality during cold storage. For 35 days, 1-day-old 320 broiler chicks (Ross) were divided into 8 groups and supplemented the diet; basal diet only (CONTROL), CONTROL with antibiotics (AB), vitamin E 20 IU (VE20), vitamin E 200 IU (VE200), quercetin 20 ppm (QC20), quercetin 200 ppm (QC200), methoxylated quercetin 20 ppm (MQ20), and methoxylated quercetin 200 ppm (MQ200). After slaughtering the broilers, thighs were separated and analyzed the quality change of the meat during storage at $4^{\circ}C$ for 7 days. The meat quality factors such as pH, color, water holding capacity, and sensory characteristics of thigh meat were determined on the experiment day 0, 3, and 7. After slaughtering, the pH of AB, VE 20, QC 20, and MQ 200 showed no significant difference compare to that of CONTROL. However, VE 200 and QC 20 showed higher pH value than CONTROL on storage day 3. $L^*$ value of chicken thigh of MQ 20 was lower than CONTROL on storage day 0, however, no significant difference was found between CONTROL and treatments on storage day 3. Redness ($a^*$) of chicken thigh in CONTROL was increased during storage. QC 20, QC 200, and MQ 200 significantly reduced the $b^*$ value of chicken thigh (p<0.05). Water holding capacity of VE 20 and MQ 200 was significantly higher than the CONTROL on the day 0. Also, QC 200 showed higher WHC compare to the CONTROL. In sensory evaluation, overall acceptability of chicken thigh in quercetin and methoxylated quercetin group showed no significant differences compare to that of CONTROL by storage day 3. These results suggested that the quercetin and methoxylated quercetin could be used as additives to enhance broiler thigh meat quality such as pH and WHC without adverse effect on color and sensory characteristics.