This study aimed to investigate the validation and modify the analytical method to determine quercetin- 3-o-gentiobioside and isoquercitrin in Abelmoschus esculentus L. Moench for the standardization of ingredients in development of functional health products. The analytical method was validated based on the ICH (International Conference for Harmonization) guidelines to verify the reliability and validity there of on the specificity, linearity, accuracy, precision, detection limit and quantification limit. For the HPLC analysis method, the peak retention time of the index component of the standard solution and the peak retention time of the index component of A. esculentus L. Moench powder sample were consistent with the spectra thereof, confirming the specificity. The calibration curves of quercetin-3-o-gentiobioside and isoquercitrin showed a linearity with a near-one correlation coefficient (0.9999 and 0.9999), indicating the high suitability thereof for the analysis. A. esculentus L. Moench powder sample of a known concentration were prepared with low, medium, and high concentrations of standard substances and were calculated for the precision and accuracy. The precision of quercetin-3-o-gentiobioside and isoquercitrin was confirmed for intraday and daily. As a result, the intra-day precision was found to be 0.50-1.48% and 0.77-2.87%, and the daily precision to be 0.07-3.37% and 0.58-1.37%, implying an excellent precision at level below 5%. As a result of accuracy measurement, the intra-day accuracy of quercetin-3-o-gentiobioside and isoquercitrin was found to be 104.87-109.64% and the daily accuracy thereof was found to be 106.85-109.06%, reflecting high level of accuracy. The detection limits of quercetin-3-o-gentiobioside and isoquercitrin were 0.24 μg/mL and 0.16 μg/mL, respectively, whereas the quantitation limits were 0.71 μg/mL and 0.49 μg/mL, confirming that detection was valid at the low concentrations as well. From the analysis, the established analytical method was proven to be excellent with high level of results from the verification on the specificity, linearity, precision, accuracy, detection limit and quantitation limit thereof. In addition, as a result of analyzing the content of A. esculentus L. Moench powder samples using a validated analytical method, quercetin-3-o-gentiobioside was analyzed to contain 1.49±0.01 mg/dry weight g, while isoquercitrin contained 1.39±0.01 mg/dry weight g. The study was conducted to verify that the simultaneous analysis on quercetin-3-o-gentiobioside and isoquercitrin, the indicators of A. esculentus L. Moench, is a scientifically reliable and suitable analytical method.

A high-cholesterol diet can reduce male fertility. However, it is not known whether a high-cholesterol diet can regulate the expression of genes involved in sperm maturation and sperm fertilizing ability. Quercetin, a natural product, is known to have cytoprotective effects by regulating lipid metabolism in various cell types. This study aimed to confirm the expression of genes involved in sperm maturation in the testes of mice fed a high-cholesterol diet and to determine whether quercetin can reverse the genetic regulation of cholesterol. Mice were divided into groups fed a normal chow diet and a high-cholesterol diet. Mice fed the high-cholesterol diet were dose-dependently supplemented with quercetin for 6 weeks. Investigations using quantitative PCR and in situ hybridization revealed that the high-cholesterol diet alters the expression of genes associated with sperm maturation in the testes of mice, and this was reversed with the supplementation of quercetin. In addition, the high-cholesterol diet regulated the expression of genes related to lipid metabolism in the liver of mice. Under a high-cholesterol diet, quercetin can improve male fertility by regulating the expression of genes involved in sperm maturation.

본 연구는 연잎, 상엽, 건조 무 혼합 추출물의 wogonin, quercetin, quercetin-3-O-glucuronide의 함량 분석 및 해당 표준물질들의 동시 분석법의 개발 및 검증을 실시하였다. 분석법은 특이성, 직선성, 정확성, 정밀성, 검출한계 및 정량한계를 통하여 분석법의 신뢰성을 검증했다. HPLC를 이용한 분석방법에서 표준용액의 머무름 시간과 연잎, 상엽, 건조 무 혼합 추출물 중 quercetin-3-O-glucuronide의 머무름 시간이 일치하였으며 동일한 spectrum을 나타내는 것을 확인해 분석법의 특이성을 검증하였다. Wogonin, quercetin 및 quercetin-3-O-glucuronide의 검량선은 상관계수 값이 wogonin, quercetin 및 quercetin-3-O-glucuronide 모두 0.9999로 우수한 직선성을 보여 분석에 적합함을 알 수 있었고 정밀성과 정확성은 농도를 아는 시료에 인위적으로 저농도, 중농도, 고농도의 표준물질을 첨가해 계산하였다. Wogonin, quercetin, quercetin-3-O-glucuronide의 정밀성은 일간 정밀성, 일내 정밀성으로 확인했으며 세 가지 성분들의 일간 정밀성은 각각 0.76~1.24%, 0.90~1.40%, 0.74~1.87% 수준으로 확인되었고, 일내 정밀성은 0.12~1.06%, 0.28~1.12%, 0.52~0.92%로 5% 이하의 우수한 정밀성을 보였다. 정확성의 측정 결과 wogonin, quercetin 및 quercetin-3-O-glucuronide의 일간 정확성은 99.99~107.97%, 99.96~115.88%, 99.73~111.91%를 나타냈고 일내 정확성은 100.36~108.88%, 99.77~114.81%, 99.91~112.44%로 우수한 수준의 정확성을 보였다. Wogonin, quercetin 및 quercetin-3-O-glucuronide의 검출한계는 각각 0.16 μg/mL, 0.09 μg/mL, 0.15 μg/mL로 측정됐으며 정량한계는 각각 0.48 μg/mL, 0.26 μg/mL, 0.45 μg/mL로 나타나 저농도에서도 검출이 가능함을 확인할 수 있었다. 분석법 검증결과, 확립된 분석법은 특이성, 직선성, 정밀성, 정확성, 검출한계 및 정량한계가 모두 우수한 분석법임이 검증됐으며, 검증된 분석법을 이용해 연잎, 상엽, 건조 무 혼합 추출물의 wogonin, quercein, quercetin-3-O-glucuronide의 함량을 분석한 결과 wogonin과 quercetin은 검출이 되지 않았지만 quercetin-3-O-glucuronide는 함량을 가지고 있는 것으로 확인됐다. 본 연구 결과 에탄올로 추출한 11번(EM11) 샘플에서 quercetin-3-O-glucuronide의 함량이 가장 높게 나왔으며 열수와 에탄올로 추출한 샘플들이 함유하고 있는 quercetin-3-Oglucuronide의 함량은 불검출~50.95 mg/dry weight g 수준으로 함유되어 있는 결과를 보였다.

In this study, using the surface dielectric barrier discharge (DBD) produced at atmospheric pressure to improve the physiological activities of quercetin was investigated. Quercetin (at 200 ppm) was treated using air DBD with an input power of 250 W. The tyrosinase inhibition effect and total phenolic content of quercetin increased from 38.96 to 91.58% and from 134.53 to 152.93 ppm, respectively, after 20 min of plasma treatment. The antioxidant activity of quercetin treated for 20 min in the lipid models was higher than that of quercetin treated for 0, 5, and 10 min. Furthermore, plasma-treated quercetin exhibited antimicrobial activity against Listeria monocytogenes, Salmonella Typhimurium, and Staphylococcus aureus, whereas activity was not shown in the control. Structural modifications of the quercetin molecule induced by plasma might be responsible for the improvements in its physiological activity. These results indicate that DBD plasma could be used to enhance the physiological activity of quercetin for various applications in food.

A total of nine Korean indigenous goats were used in a cross-over arrangement to give nine replicates per treatment, and they were housed individually assigned to 1 of 9 dietary treatments. Nine treatments were 0, 500, and 1000 ppm of quercetin supplementation in diets by mixing roughage and concentrate with different ratios (RC ratio) of 3:7 (RC 30), 5:5 (RC 50) and 7:3 (RC 70). Nutrient utilizations of dry matter, crude fat and NDF were not affected by neither RC ratio nor dietary quercetin (p>0.05), but the rate of crude protein and ADF increased in animals in RC 70 group regardless of quercetin supplementation (p<0.05). In addition, higher RC ratio increased (p<0.05) N retention and N retention rate. Total VFA, acetic acid, propionic acid, iso-butyric acid, butyric acid, iso-valeric acid and valeric acid contents were not affected (p>0.05) by dietary quercetin. Meanwhile, lower total cholesterol level exhibited in animals in RC 70 group compared to RC 30 or 50 groups, unrelated to dietary quercetin (p<0.05), however other plasma parameters were not influenced (p>0.05) by RC ratio and dietary quercetin. Our results indicated that both RC ratio and dietary quercetin may not directly affect the production indices and immune responses in Korean indigenous goat

식물에서 흔히 존재하는 isoquercetin의 유전독성을 평가하기 위하여 최종평가항목인 DNA 절단 및 염색체 손상을 quercetin과 비교 평가하였다. 7주령의 수컷 ICR 마우스를 사용하였고 3일 동안 시험물질을 경구로 투여하였다. 부형제로 0.5% carboxymethylcellulose를 사용하였고 isoquercetin과 quercetin은 각각 250, 500 mg/kg/day로 투여하였으며, 양성대조물질로 ethyl methanesulfonate 200mg/kg/day를 사용하였다. 일차 투여 후 48시간에 그리고 마지막 투여 후 3시간 내에 부검하였고 조직을 적출하였다. DNA 손상은 Comet assay를 사용하여 위와 간세포에서 관찰하였고, 소핵시험은 골수세포에서 소핵 분석방법을 사용하여 평가하였다. 두 가지 유전독성 시험을 동일마우스를 사용하여 수행하였다. 그 결과, isoquercetin과 quercetin의 경구 투여는 500 mg/kg/day에서도 위와 간에서 DNA 손상을 초래하지 않았으며 골수세포에서 소핵을 유발하지 않았다. 따라서 본 연구에서 사용한 플라보노이드는 본 실험 조건하에서 유전독성을 유발하지 않는 것으로 사료된다.

Quercetin is a natural flavonoid phytochemical that is extracted from various plants. Having an advantages due to its varied biological properties, such as anti-inflammatory, anti-viral, anti-oxidant, and anti-cancer effects, quercetin is used to treat many diseases. Recently, it has been reported that autophagy inhibition may play a key role in anti-cancer therapy. Therefore, in this study, we investigated the molecular mechanisms and anti-cancer effects of quercetin in human osteosarcoma cells via autophagy inhibition. We ascertained that quercetin inhibited cell proliferation and induced cell death, these process is demonstrated that apoptosis via the mitochondrial pathway and the caspase cascade. Quercetin also induced autophagy which was inhibited by 3-MA, autophagy inhibitor and the blockade of autophagy promoted the quercetin-induced apoptosis, confirming that autophagy is a pro-survival process. Thus, these findings demonstrate that quercetin is an effective anti-cancer agent, and the combination of quercetin and an autophagy inhibitor should enhance the effect of anti-cancer therapy.

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 μM for 6 hr incubation compared to control (p<0.05). The sperm viability was increased by addition of quercetin 1 and 50 μM and genestein 1 and 50 μM for 3 hr incubation. In addition, the sperm viability seemed to be increased dose-dependantly by addition of quercetin or genistein 1 and 50 μM, 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 μM for 3 hr incubation. In mitochondrial activities, addition of quercetin 50 μM for 6 hr incubation increased mitochondrial activity but decreased at 100 μM concentration compared with control (p<0.05). When porcine IVF embryos were cultured in PZM-3 medium supplemented with low concentrations of quercetin (1∼10 μM), the developmental rates to morula and blastocyst increased but significantly decreased at high concentrations of quercetin (25∼50 μM). The highest developmental rate to blastocysts among all concentrations of quercetin was shown at quercetin 10 μM (p<0.05). The developmental rates to morula or blastocysts at low (0.01∼1 μM) and high (5∼10 μM) 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 μM) 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∼10 μM).

양파 과육부에 함유되어 있는 유용 성분인 quercetin과 그 배당체를 다양한 착즙 및 추출방법에 따른 수율을 측정, 분석하였으며 그 결과를 요약하면 다음과 같다. 양파과육의 quercetin과 배당체의 최적 추출 조건으로는 50oC에서 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±0.002 mg/g인 것으로 나타났다.

In order to compare the suppressive effect of quercetin and several its glycosides, such as quercitrin (quercetin-3-rhamnoside), isoquercitrin (quercetin-3-gluooside), hyperin (quercetin-3-galactoside) and rutin (quercetin-3-rhamnosyl glucoside), on the genotoxicity by Nmethyl-N-nitrosourea(MNU), in vitro sister chromatid exchange(SCE) test using mouse spleen lymphocytes and in viuo micronucleus test using mouse peripheral blood were performed. MNU-indured SCEs in vitro were not decreased by the simultaneous treatment of teat compounds. Among them, quercetin and hyperin showed significant suppressive effects at high dose(10^(-5)M). On the other hand, MNU-induced micronucleated reticulocytes(MNRETs) in vivo were aignificantly decreased with good dose-dependent manner in all compounds tested. However, there were not significant differences between quercetin aglycone and its glycosides in the suppressive effects under experimental condition of this study. These results suggest that both of queroetin aglycone and its glycosides may act as an antigenotoxic agent in vivo and may be useful as a chemopreventive agent of alkylating agent.

Dendropanax morbifera Leveille (Araliaceae) is an endemic species growing in the south-western part of South Korea that has been used in folk medicine and health functional food. In this study, we investigated an extract of quercetin in Jeju D. morbifera by varying different parts (fruit, sprouts, leaves, sprigs, and branches), harvest times, and extraction solvents. In addition, we aimed to establish a simple and reliable HPLC/UV analytical method to determination of quercetin for the quality control and base line data of the Jeju D. morbifera extract as a health functional food ingredient. The analytical specificity was determined with retention time and photo diode array (PDA) spectrum by analyzing quercetin using HPLC and comparing the results to those of extracts. This analytical method for quercetin was validated for its limit of detection (LOD), limit of quantitation (LOQ), precision, and accuracy. A high linearity in the standard calibration curve was obtained, with a coefficient of determination (R2) of 0.9996. Also, the LOD and LOQ values were found to be 0.28 μg/mL and 0.85 μg/mL, respectively, and the recoveries of quantified compounds ranged from 97.91% to 104.10%. Furthermore, the relative standard deviation (RSD) values of data from the intra- and inter-day precision analyses were less than 1.36% and 3.65%, respectively. As a result, the highest quercetin content among the extracts of Jeju D. morbifera leaves was found to be 20.14 mg/g, which was extracted at harvest in May (cultivation period 10 years) with 60% EtOH. All in all, we believe that the results obtained would be helpful in the development of nutraceutics and natural medicines and for the quality control of D. morbifera.

수온은 어류를 포함한 수중동물의 다양한 생물학적 사건에 영향을 미친다. 어류의 번식 및 발생도 수온의 변화와 밀접한 관련이 있다. 어류를 높은 수온에 노출시키면 HSP70 유전자 발현을 유도한다. 따라서, HSP70 유전자 발현을 효과적으로 차단할 수 있는 저해제의 개발은 온도에 민감한 생물학적 사건과 관련된 HSP70의 역할을 연구하는데 크게 기여할 수 있다. 본 연구에서는 고온()에 노출된 틸라피아 자어와 치어(전장 10~13 cm)에서 천연 fla

Taxifolin-3-O-β-D-xylopyranoside and quercetin-3-O-α-L-rhamnopyranoside were isolated from an EtOAc-soluble extract of the leaves of Chamaecyparis obtuse. Quercetin-3-O-α-L-rhamnopyranoside was found to possess a potent inhibitory activity of human recombinant aldose reductase in vitro, its IC50 value being 11.5 μM. Kinetic analysis showed that quercetin-3-O-α-L-rhamnopyranoside exhibited uncompetitive inhibition against DL-glyceraldehyde. Also, quercetin-3-O-α-L-rhamnopyranoside suppresses sorbitol accumulation in rat lens under high glucose conditions, demonstrating the potential to prevent sorbitol accumulation in vivo. These results suggest that this compound may be a promising agent in the prevention or treatment of diabetic complications.