• Journal of Pharmaceutical Investigation
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• 제34권4호
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• pp.283-288
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• 2004

The pharmacokinetics of nifedipine was studied after oral coadministration of nifedipine (5 mg/kg) with quercetin (1.5, 7.5, 15 and 30 mg/kg, respectively) and 0.5 h or 3days pretreatment with quercetin (1.5 and 7.5mg/kg) in rabbits. Pretreatment of quercetin significantly (p<0.05, at 0.5 h; p<0.01, at 3 days) increased the plasma concentration of nifedipine, but not significant in coadministraiton. The area under the plasma concentration-time curve (AUC) and the peak concentration $(C_{max})$ of nifedipine pretreated with quercetin were increased significantly (p<0.05, at 0.5 h; p<0.01, at 3 days) compared to the control. By coadministration of quercetin, only 7.5 mg/kg of quercetin increased plasma AUC and $C_{max}$ of nifedipine significantly (p<0.05) compared to the control. Plasma AUC of intravenous nifedipine (1 mg/kg) is $4235\;{\pm}\;1192\;ng/ml{\cdot}hr$. Pretreatment of quercetin significantly (p<0.05, at 0.5 h; p<0.01, at 3 days) increased the absolute bioavailability (AB%) of nifedipine to 23.9-29.2% compared to the control (17.8%). Coadministration of quercetin showed no significant effect on the AB% of nifedipine except for 7.5 mg/kg. It is suggested that quercetin alters disposition of nifedipine by inhibition of P-glycoprotein efflux pump and its first-pass metabolism. The dosage of nifedipine should be adjusted when it is administered chronically with quercetin in a clinical situation.

• Asian-Australasian Journal of Animal Sciences
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• 제23권6호
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• pp.742-749
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• 2010

We investigated the antioxidant efficacy of quercetin (0% Diet 1, 0.25% Diet 2, and 0.5% Diet 3) pretreatment for 30 and 60 days in response to cadmium (Cd) toxicity in the olive flounder, and measured the plasma lysozyme activity to understand the immune effects of quercetin. The lysozyme activity with Diets 2 and 3 was higher than with Diet 1. Based on this result, to examine the immune ability and antioxidant role of quercetin, we exposed olive flounder fed quercetin to Cd and then measured the expression and activity of antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) and lipid peroxidation (LPO). With Diets 2 and 3, the expression and activity of antioxidant enzymes and the $H_2O_2$ concentration were lower than with Diet 1. In addition, the LPO levels were lower than with Diet 1, which protected the cell membrane. Therefore, quercetin removed the reactive oxygen species (ROS) produced by Cd, indicating that quercetin has antioxidant ability. In addition to its antioxidant ability, quercetin has immune effects.

• 산업식품공학
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• 제13권2호
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• pp.147-153
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• 2009

양파 과육부에 함유되어 있는 유용 성분인 quercetin과 그 배당체를 다양한 착즙 및 추출방법에 따른 수율을 측정, 분석하였으며 그 결과를 요약하면 다음과 같다. 양파과육 의 quercetin과 배당체의 최적 추출 조건으로는 50$^{\circ}C$에서 60% methanol를 용매로 사용했을 때 15분의 추출시간인 것으로 나왔으며 용매와 시료의 비율이 0.8 mL/g일 때 추출 수율이 가장 좋았다. 초음파를 60분 동안 처리 시 대조군에 비하여 2.06배의 추출 증가 효과를 볼 수 있었으며 microwave는 60초 조사 시에 최대의 추출 증가 효과를 나타내어 microwave를 처리하지 않은 시료와 비교하여 quercetin과 배당체가 2.14배 많이 추출되었다. 효소 처리 시 cellulase 용액과 시료의 비율이 0.5 mL/g일 때 quercetin과 배당체의 수율이 가장 높았으며 1.65 배 더 많이 추출되었고 viscozyme과 시료의 비율이 0.5 mL/g일 때 quercetin과 배당체의 수율이 가장 높았으며 추출증가율은 2.29 배인 것으로 나왔다. 가장 많은 quercetin과 배당체의 추출 수율을 보인 방법은 viscozyme과 시료의 비율이 0.5 mL/g일 때의 0.070${\pm}$0.002 mg/g인 것으로 나타났다.

• The Korean Journal of Physiology and Pharmacology
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• 제13권5호
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• pp.361-365
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• 2009

Effects of quercetin, a kind of flavonoids, on the vasodilating actions were investigated. Among the mechanisms for quercetin-induced vasodilatation in rat aorta, the involvement with the $Ca^{2+}$ activated $K^+$ ($K_{Ca}$) channel was examined. Pretreatment with NE ($5\;{\mu}M$) or KCl (60 mM) was carried out and then, the modulation by quercetin of the constriction was examined using rat aorta ring strips (3 mm) at $36.5^{\circ}C$. Quercetin (0.1 to $100\;{\mu}M$) relaxed the NE-induced vasoconstrictions in a concentrationdependent manner. NO synthesis (NOS) inhibitor, NG-monomethyl-L-arginine acetate (L-NMMA), at $100\;{\mu}M$ reduced the quercetin ($100\;{\mu}M$)-induced vasodilatation from $97.8{\pm}3.7%$ (n=10) to $78.0{\pm}11.6%$ (n=5, p<0.05). Another NOS inhibitor, L-NG-nitro arginine methyl ester (L-NAME), at $10\;{\mu}M$ also had the similar effect. In the presence of both $100\;{\mu}M$ L-NMMA and $10\;{\mu}M$ indomethacin, the quercetin-induced vasodilatation was further attenuated by $100\;{\mu}M$ tetraethylammonium (TEA, a $K_{Ca}$ channel inhibitor). Also TEA decreased the quercetin-induced vasodilatation in endothelium-denuded rat aorta. Used other $K_{Ca}$ channel inhibitors, the quercetin-induced vasodilatation was attenuated by $0.3\;{\mu}M$ apamin (a SK channel inhibitor), but not by 30 nM charybdotoxin (a BK and IK channel inhibitor). Quercetin caused a concentration-dependent vasodilatation, due to the endotheliumdependent and -independent actions. Also quercetin contributes to the vasodilatation selectively with SK channel on smooth muscle.

• Nutrition Research and Practice
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• 제6권4호
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• pp.301-307
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• 2012

Radiation used in cancer treatment may cause side effects such as inflammation. Quercetin is a polyphenol that reduces inflammation. This study evaluated the recovery efficacy of quercetin on impaired immune function in irradiation-induced inflammatory mice. Quercetin administered at two concentrations of 10 and 40 mg/kg body weight was initiated 2 weeks before irradiation and was continued 30 days after irradiation. The animals exposed/not exposed to radiation were sacrificed on radiation days 10 and 30. Splenocyte proliferation, which was diminished after irradiation, was enhanced significantly by quercetin supplementation after 30 days of irradiation. Cytokine secretion increased in the radiation group compared to that in the non-radiation control group. After 30 days of radiation, interleukin (IL)-$1{\beta}$ and IL-6 secretion decreased significantly in the radiation-quercetin groups. When quercetin was administered for 44 days, it showed a possible protective effect against irradiation-induced inflammation in mice. Quercetin could be beneficial in the recovery of irradiation-induced increases in cytokine secretion.

• 한국가금학회지
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• 제37권4호
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• pp.405-413
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• 2010

본 연구는 quercetin의 급여가 닭고기 다리육의 지방산패 억제 효과에 미치는 영향을 구명하고자 실시하였다. 1일령 Ross 320마리 육계 병아리를 8처리군으로 나누어 대조군(T1), 항생제 처리군(T2), 비타민 E 20 ppm 처리군(T3), 비타민 E 200 ppm 처리군(T4), quercetin 20 ppm(T5), quercetin 200 ppm(T6), methoxylated quercetin 20ppm(T7), methoxylated quercetin 200 ppm(T8) 처리구로 나누어 35일간 급여하였다. 급여 후 36일째 도계하여 다리육만 분리하였고, 0, 3, 7일 냉장 저장 기간 동안의 단백질 변패도(VBN), 지방산패도(TBARS), 지방산 조성 변화, 미생물학적 특성을 조사하였다. 저장 3일에는 대조군보다 항생제처리군(T2), 비타민 E처리군(T3, T4)와 quercetin 20 ppm 처리군(T5)에서 유의적인 감소를 나타내어 quercetin 20 ppm의 높은 단백질 산패 억제 효과를 보였다(P<0.05). 도계 직후 다리살의 지방산패도는 대조군보다 비타민 E 200 IU 급여한 T4에서 가장 낮은 값을 나타내었으며, 이 값은 항생제 처리구인 T2, quercetin 200 ppm 첨가구인 T5와 유의적인 차이를 나타내지 않아, 비타민 E 200 IU와 유사한 항산화력을 나타냄을 보여주었다(p<0.05). 그러나 저장 7일에 quercetin 20 ppm 처리군(T5)과 200 ppm 처리군(T6)은 항생제 처리군보다도 낮은 총 균수를 나타내어 높은 항균력을 나타내었다(P<0.05). 대장균군은 도계 직후부터 냉장 저장 7일까지 quercetin 처리에 의한 유의적인 감소 효과는 없었다.

• 한국미생물·생명공학회지
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• 제34권4호
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• pp.368-372
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• 2006

Quercetin은 flavonoid 계통의 물질로서 자연계에서 채소나 과일에 매우 흔하다. 또한 인체에서는 radical scavenger로서 신체항상성 뿐만 아니라 직장암의 예방에도 중요한 역할을 한다. Glucosidase를 포함한 glycosidase는 많은 종류의 대사성 질환에 관련이 있다. 유용한 $\alpha$-glucosidase 저해제를 스크리닝 하던 중 chemical library로부터 quercetin을 선별하였다. Quercetin은 $\alpha$-glucosidase에 가역적으로, 느리게 결합하며, 비경쟁적인 저해제인데, $6.3\times10^{-8}$ M의 Ki값을 가진다. 이러한 결과는 비록 기전 연구가 더 필요하지만, quercetin이 당뇨병과 같은 퇴행성 질환을 치료할 수 있다는 잠재성을 보여주는 것이다.

• Preventive Nutrition and Food Science
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• 제22권2호
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• pp.131-137
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• 2017

Maximum production of isoquercetin and quercetin simultaneously from rutin by subcritical water hydrolysis (SWH) was optimized using the response surface methodology. Hydrolysis parameters such as temperature, time, and $CO_2$ pressure were selected as independent variables, and isoquercetin and quercetin yields were selected as dependent variables. The regression models of the yield of isoquercetin and quercetin were valid due to the high F-value and low P-value. Furthermore, the high regression coefficient indicated that the polynomial model equation provides a good approximation of experimental results. In maximum production of isoquercetin from rutin, the hydrolysis temperature was the major factor, and the temperature or time can be lower if the $CO_2$ pressure was increased high enough, thereby preventing the degradation of isoquercetin into quercetin. The yield of quercetin was considerably influenced by temperature instead of time and $CO_2$ pressure. The optimal condition for maximum production of isoquercetin and quercetin simultaneously was temperature of $171.4^{\circ}C$, time of 10.0 min, and $CO_2$ pressure of 11.0 MPa, where the predicted maximum yields of isoquercetin and quercetin were 13.7% and 53.3%, respectively. Hydrolysis temperature, time, and $CO_2$ pressure for maximum production of isoquercetin were lower than those of quercetin. Thermal degradation products such as protocatechuic acid and 2,5-dihydroxyacetophenone were observed due to pyrolysis at high temperature. It was concluded that rutin can be easily converted into isoquercetin and quercetin by SWH under $CO_2$ pressure, and this result can be applied for SWH of rutin-rich foodstuffs.

• 생명과학회지
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• 제24권3호
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• pp.290-296
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• 2014

이 연구의 목적은 mice를 이용하여 elevated plus-maze (EPM) test와 hole-board test를 통해 quercetin의 잠재적인 항불안 작용을 확인하고자 함이다. Quercetin을 1.25, 2.5, 5나 10 mg/kg의 용량으로 각각 행동시험을 측정하기 1 시간 전에 ICR mice에 경구투여하였다. 대조군은 동일한 양의 10% Tween 80을 투여하였고 양성대조군으로 buspirone 2 mg/kg을 투여하였다. Quercetin을 단회 투여하여 EPM test를 실시한 결과, 5 mg/kg 용량에서 open arm에 머문 시간 및 진입한 횟수의 백분율이 control group과 비교하여 통계적으로 유의성 있게 증가하였다(p<0.05). 또한 quercetin을 투여하여 hole-board test를 실시한 결과, 5 mg/kg 용량에서 구멍에 머리를 넣은 횟수가 control group과 비교하여 통계적으로 유의성 있게 증가하였다(p<0.05). 또한 quercetin와 flumazenil ($GABA_A$ antagonist), WAY-100635 ($GABA_{A-{\rho}}$ antagonist) 또는 trans-4-aminocrotonic acid ($GABA_{A-{\rho}}$ agonist)를 병용투여하여 elevated plus-maze를 실험을 하여 신경계와의 관계를 확인한 결과, trans-4-aminocrotonic acid에서만 quercetin의 항불안 작용이 차단되었음을 확인 할 수 있었다. 결론적으로, 본 연구의 결과에서 quercetin이 elevated plus-maze 및 hole-board test, horizontal wire test, open field test를 통하여 locomotor activity 및 근육이완이나 진정 등의 부작용이 없으면서 우수한 항불안 작용을 가지는 소재라고 생각되며 이러한 작용이 특히 GABA 신경계와 관련이 있음을 시사하고 있다.

• The Korean Journal of Physiology and Pharmacology
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• 제23권5호
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• pp.381-392
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• 2019

Sperm function and male fertility are closely related to pH dependent $K^+$ current (KSper) in human sperm, which is most likely composed of Slo3 and its auxiliary subunit leucine-rich repeat-containing protein 52 (LRRC52). Onion peel extract (OPE) and its major active ingredient quercetin are widely used as fertility enhancers; however, the effect of OPE and quercetin on Slo3 has not been elucidated. The purpose of this study is to investigate the effect of quercetin on human Slo3 channels. Human Slo3 and LRRC52 were co-transfected into HEK293 cells and pharmacological properties were studied with the whole cell patch clamp technique. We successfully expressed and measured pH sensitive and calcium insensitive Slo3 currents in HEK293 cells. We found that OPE and its key ingredient quercetin inhibit Slo3 currents. Inhibition by quercetin is dose dependent and this degree of inhibition decreases with elevating internal alkalization and internal free calcium concentrations. Functional moieties in the quercetin polyphenolic ring govern the degree of inhibition of Slo3 by quercetin, and the composition of such functional moieties are sensitive to the pH of the medium. These results suggest that quercetin inhibits Slo3 in a pH and calcium dependent manner. Therefore, we surmise that quercetin induced depolarization in spermatozoa may enhance the voltage gated proton channel (Hv1), and activate non-selective cation channels of sperm (CatSper) dependent calcium influx to trigger sperm capacitation and acrosome reaction.