• 생명과학회지
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• 제19권10호
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• pp.1444-1450
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• 2009

본 연구를 통해 BALB/c 마우스에서 quercetin의 경구투여가 PCL로 유도된 접촉성 피부 알레르기의 예방에 미치는 효과에 대해 알아보았다. Quercetin을 투여 농도에 따라 대조군(0 mg/kg), 저용량군(50 mg/kg), 고용량군(100 mg/kg)으로 나누고 8일에 걸쳐 총 8번 경구투여를 실시한 후 알레르기 유발물질인 PCL을 마우스의 양쪽 귀에 감작시켜 접촉성 피부 알레르기를 유발 시켰다. Quercetin의 투여 농도별 ear swelling 변화를 확인한 결과 quercetin을 투여하지 않은 대조군에 비해 quercetin을 투여한 군의 ear swelling 증가폭이 낮게 나타났고, 100 mg/kg (고용량군)에서 농도 유의적으로 ear swelling의 증가폭이 현저히 낮게 나타났다. Quercetin의 투여 농도에 따른 혈청 내 염증성 매개 물질의 농도 변화를 알아보기 위한 IgE 및 histamine level 측정 결과에서 quercetin을 투여하지 않은 대조군에 비해 quercetin을 투여한 50 mg/kg (저용량군), 100 mg/kg (고용량군)에서 낮은 수준의 IgE, histamine 수치가 나왔다. H&E염색과 Toluidine blue stain을 통한 조직병리학적 검사결과에서 quercetin을 투여한 고용량군의 귀 두께가 대조군에 비해 얇게 관찰되었고, 비만세포의 유무를 알아보기 위한 Toluidine blue stain의 결과 대조군에 비해 고용량군에서 적은 수의 비만세포들이 관찰되었다. 따라서 ear swelling과 IgE, histamine level, 조직병리학적 결과를 종합해 봤을 때 식물성 flavonoid 성분인 quercetin은 접촉성 피부 알레르기의 예방에 상당한 효과가 있다고 판단되며, 부작용이 발생하는 기존의 치료제를 대체할 수 있는 후보 물질로써 중요한 가치가 있다고 사료된다.

• 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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• 제21권3호
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• pp.464-467
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• 2011

퀘세틴은 양파에 있는 주요한 플라보노이드이고, 항산화제 역할을 한다. 양파에 있는 퀘세틴은 주로 배당체 형태로 존재한다. 흑양파는 습도 90%와 온도 $60^{\circ}C$ 조건 하에서 30일 동안의 숙성처리과정으로 만들어진다. 흑양파 제조과정 전후의 양파 속에 있는 퀘세틴과 퀘세틴 배당체들은 HPLC-ESI/MS/MS를 이용하여 분석되었다. 생양파 속에는 퀘세틴 단당체와 퀘세틴 이당체가 동정되었고, 반면에 흑양파 속에는 퀘세틴만이 존재하였다. 그러한 결과들은 생양파에 있는 퀘세틴 배당체(단당체와 이당체)들은 숙성과정 동안 해당과정이 일어난다는 것을 의미한다. 이러한 분석프로파일은 숙성과정 동안 발생되는 양파의 주요한 두 개의 퀘세틴 배당체들의 변화를 추정하는데 용이한 방법을 제공할 것이다.

• 한국약용작물학회지
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• 제10권1호
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• pp.12-16
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• 2002

약용작물은 재배환경, 재배방법, 생육 시기 및 부위별로 약리성분 함량에 차이가 많은데, 이뇨, 진통, 지혈, 조직재생 및 혈관확장 등의 약리효과가 있다고 보고된 어성초를 생육 시기별, 부위별 및 퇴비 시용량별로 유효성분 함량을 분석한 결과는 다음과 같다. 생육 시기별 quercetin 및 tannin 함량은 생육 초기인 4월 20일에 채취하였을 때 각각 0.72, 2.1%로 함량이 가장 높았으며, 개화기 전까지 감소하다가 개화기 이후로 증가하였다. 부위별 quercetin 및 tannin 함량은 꽃에서 2.06, 5.3%로 가장 높았으며, 잎, 줄기, 뿌리 중에서는 잎에서 각각 0.81 및 2.3%로 높았다. 퇴비 시용량별 어성초의 quercetin 및 tannin함량은 무처리구에서 각각 0.67 및 2.3%로 가장 높았고, 퇴비시용량이 증가할 수록 지상부 수량은 증가하였으나 유효성분 함량은 감소하였다.

• Journal of Periodontal and Implant Science
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• 제43권4호
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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.

• The Korean Journal of Physiology and Pharmacology
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• 제15권5호
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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.

• 약학회지
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• 제42권1호
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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.

• 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.

• 생약학회지
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• 제33권4호통권131호
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• pp.285-290
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• 2002

From the fruits of Crataegus pinnatifide BUNGE ursolic acid (1), $quercetin-3-O-{\alpha}-L-rhamnopyranosyl(1{\rightarrow}6)-{\beta}-D-glucopyranoside$ (2), (-)-epicatechin (3), $quercetin-3-O-{\beta}-D-galactopyranoside$ (4) and quercetin (5) have been isolated and identified on the basis of their physicochemical properties and spectroscopic evidences in comparison with authentic samples. Among isolated compounds, quercetin showed significant inhibitory effect against MAO.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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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.