• 한국잠사곤충학회지
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• 제42권1호
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• pp.6-9
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• 2000

This study was performed to investigate the catechins which separated from mulberry leaf. The Epicatechin contents in mulberry leves was 1.21${\pm}$0.05 $\mu\textrm{g}$/mg ethylacetate fraction. epigalocatechingallte contents WAS 3.56 $\mu\textrm{g}$/mg ethylacetate fraction. The cathechins (epicatechin and epigalocate-chingallate) separated from mulberry leaf was shown a strong activity to growth inhibition by the concentration of 5 mg/disc on the Clostridium perfringens.

• 한국식품위생안전성학회지
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• 제11권2호
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• pp.77-82
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• 1996

Green tea catechins(GTC) were studied for its inhibitory effect on human platelet aggregation in vitro, for its antithrombotic effect in mice in viro, and bleeding and clotting time in rats. The catechins were isolated and purified from green tea, which were composed of (-)-epigallocatechin gallate, (-)-epigallocatechin, (-)epicatechin gallate and (-)-epicatechin, GTC produced a potent inhibition of human platelet aggregation in a dose-dependent manner against the stimulants such as ADP, collagen, epinephrine and ristocetin n vitro. GTC also prevented death due to the formation of pulmonary thrombosis by platelet aggregates in mice in a dose-de-pendent manner in viro. GTC increased the bleeding time, whole blood clotting time and plasma clotting time in rats, too. These results suggest that GTC is a promising antithrombotic agent.

• Asian-Australasian Journal of Animal Sciences
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• 제25권6호
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• pp.832-838
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• 2012

This study was conducted to evaluate the effects of dietary supplementation of catechins and wheat bran on growth performance, carcass characteristics and meat color using forty-eight Hanwoo steers. Each steer was randomly assigned to one of four treatments. Treatments were as follows: control, catechins, wheat bran, and catechins+wheat bran (CW). At the end of the feeding trial, blood samples were collected for analysis of hemoglobin and iron concentration, and then steers were slaughtered at a commercial abattoir. Catechins, wheat bran, and CW had no effect on growth performance and carcass characteristics. Percentage of myoglobin in M. longissimus dorsi was not affected by treatments. Percentage of oxymyoglobin was increased (p<0.05) by CW and maintained at the highest level (p<0.05) for CW during meat display time up to 24 h. Percentage of metmyoglobin was the lowest (p<0.05) for CW between 5 and 24 h during display time. Although blood iron concentration was not affected by treatments, total concentration of muscle iron was the lowest (p<0.05) for CW compared with that of other treatments. Therefore, the results of the present study suggest that CW may provide good protection against oxidation of myoglobin, and might be an effective dietary supplement for improving meat color in the late fattening period of Hanwoo steers.

• 한국작물학회지
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• 제53권2호
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• pp.224-232
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• 2008

고 기능성 유용 차나무 품종육성 및 녹차의 이용성 증진 연구의 기초 자료를 제공하기 위해 녹차 함유 catechin 화합물 및 caffeine 성분을 동시에 분석할 수 있고, 재현성 및 검출 감도가 증진된 최적의 HPLC 분석 조건을 검토한 결과를 요약하면 다음과 같다. 1. 녹차에 함유된 catechin 화합물 및 caffeine의 동시분석을 위한 최적 HPLC 분석 조건을 검토한 결과 컬럼은 YMC-pak ODS-AM 303(25 cm)컬럼을 이용하고, 검출파장은 280 nm, 컬럼온도를 $30^{\circ}C$, 분당유속은 1 mL, 이동상 용매로는 A용매로 0.1% 인산 - 증류수, B용매로 100% MeOH를 사용하여 농도구배 조건으로 분석하는 것이 가장 효율적 분석법으로 조사되었다. 2. 녹차에 함유된 catechin 화합물 및 caffeine을 동시에 분석할 수 있는 최적 HPLC분석조건의 재현성 검정을 실시한 결과 머무름 시간(Rt.)의 변이계수는 최대 1.23% 미만, peak area의 변이계수는 최대 5.13% 미만을 나타내어 확립된 녹차 함유 catechin 9종 화합물 및 caffeine의 HPLC 정량분석법은 재현성이 높은 분석법으로 확인되었고, 각 cafechin 화합물 및 caffeine 성분의 최소 검출한계는 최소 50ppb(0.050 ppm, 50 ng/mL)이하로 조사되어, 확립된 HPLC 분석법은 녹차의 작물학적 특성 평가용으로 활용하기에 전혀 무리가 없는 분석법으로 판단되었다.

• 한국식품영양과학회:학술대회논문집
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• 한국식품영양과학회 2001년도 International Symposium on Food,Nutrition and Health for 21st Century
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• pp.74-87
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• 2001

Evidence shows that the serum level of cholesterol (CH) is decreased with increasing green tea (GT) consumption. This presentation summarizes our recent findings on the effect of GT extract on intestinal absorption of [$^{14}C$-labeled CH and phosphatidylcholine (PC). Ovariectomized (OX) adult rats were infused intraduodenally with lipid emulsions containing radiolabeled lipids [$^{14}C$-CH or $^{14}C$-phosphatidylcholine (PC)] in the presence of GT extract or catechins to determine the rates and amounts of CH absorption and the intestinal hydrolysis and lymphatic output of PC. During lipid infusion, lymph was collected hourly for 8 h. The lymphatic absorption of $^14C$-CH was drastically lowered by infusion of GT extract at two dosage levels (GTl =5.4 mg catechins/h and GT2 = 15.1mg catechins/h). The cumulative lymphatic absorptions of $^{14}C$-CH in rats infused with GT1 and GT2 were 20.7$\pm$4.3 and $4.8{\pm}4.1{\%}$ dose, respectively, whereas the absorption of $^{14}C$-CH in rats infused with no GT extract (GT0) was $36.3{\pm}1.1{\%}$ dose. GT extracts also significantly lowered the absorption of-tocopherol (TP) in a dose dependent manner ($29.6{\pm}4.9{\%}$ dose in GT0, $20.8{\pm}5.8{\%}$ dose in GTl, and $7.9{\pm}5.4{\%}$ dose in GT2 groups). Both (+)-catechin and EGCG significantly lowered the lymphatic outputs of $^{14}C$-radioactivity after intraduodenal $^{14}C$-PC infusion. A significantly higher amount of $^{14}C$-PC remained unhydrolyzed in the intestinal lumen of the EGCG rats ($22.8{\%}$) compared with the (+)-catechin ($15.8\%$) and control groups ($11.9\%$). GT extracts, (+)-catechin, and EGCG significantly reduced the absorption of TP. The inhibitory effect of GT extract and catechins on lipid absorption may be mediated in part through the inhibition of pancreatic PLAz. The findings provide the first direct evidence that green tea and catechins have a profound inhibitory effect on the intestinal absorption of CH in OX rats. Results suggest that green tea and catechins may be used as a dietary or pharmacological means of lowering cholesterol absorption.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2004년도 춘계학술발표회 논문집
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• pp.296-301
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• 2004

We focused our research interests on the characteristic of silk fabrics dyed with green tea extracts and, moreover, revealed the catechin content of silk fabrics after dyeing with Korean tea extract by measuring the residues. Three kinds of green tea samples were taken between April and May, 2003, from Bosung(southern province in South Korea), in different terms as the first corp, the second corp, and the third corp. Before and after dyeing the silk fabrics with these extracts, catechins in the residue were analyzed by HPLC. Four kinds of Catechins, such as (-)-epicatechin(EC), (-)-epicatechin gallate(ECG), (-)-epigallocatechin (EgC), (-)-epigallocatechin gallate(EgCG) were isolated from Korean green tea extracts. Catechine contents in Korean green tea leaves depend on the making process such as heating and steaming, and the younger the richer. The absorbed catechins in sillk fabrics after dyeing followed in a decreasing order of EgCG>EgC>ECG>EC. We have found a 68% uptake of EgCG, and 116.8mg/g of EgCG in the silk fabrics after dyeing with 1% Korean green tea extracts.

• Integrative Medicine Research
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• 제3권1호
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• pp.4-10
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• 2014

Green tea and coffee consumption have been widely popular worldwide. These beverages contain caffeine to activate the central nervous system by adenosine receptor blockade, and due to the caffeine, addiction or tolerance may occur. In addition to this caffeine effect, green tea and coffee consumption have always been at the center of discussions about human health, disease, and longevity. In particular, green tea catechins are involved in many biological activities such as antioxidation and modulation of various cellular lipid and proteins. Thus, they are beneficial against degenerative diseases, including obesity, cancer, cardiovascular diseases, and various inflammatory diseases. Some reports also suggest that daily consumption of tea catechins may help in controlling type 2 diabetes. However, other studies have reported that chronic consumption of green tea may result in hepatic failure, neuronal damage, and exacerbation of diabetes, suggesting that interindividual variations in the green tea effect are large. This review will focus on the effect of green tea catechins extracted from the Camellia sinensis plant on type 2 diabetes and obesity, and the possible mechanistic explanation for the experimental results mainly from our laboratory. It is hoped that green tea can be consumed in a suitable manner as a supplement to prevent the development of type 2 diabetes and obesity.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1310-1316
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• 2005

To evaluate the toxicological properties of human cytochrome P450 2E1 (CYP2E1) induced by ethanol and possible protective effects of various green tea catechins on alcohol-induced toxicity, transfected HepG2 cells that stably and constitutively express human CYP2E1 were established using the recombinant retroviral expression vector. Exposure of the CYP2E1-expressing HepG2 cells to high concentration of ethanol (200 mM) for 5 days resulted in a more than $50\%$ increase of cytotoxicity, assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction, lactate dehydrogenase (LDH) release, and reactive oxygen species (ROS) production, and loss of normal morphology, in comparison with HepG2 cells containing control vector. Treatment of the cells with various catechins increased cell viability by more than 2-fold. (-)-Epicatechin gallate and(-)-catechin gallate at the lowest concentration ($5\;{\mu}M$) attenuated cell death induced CYP2E1 by $60-65\%$. Therefore, the results showed that the catechins, including epimerized catechins, have strong protective effects against alcohol-induced CYP2E1 toxicity, and it is correlated with antioxidant effect.

• Preventive Nutrition and Food Science
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• 제15권3호
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• pp.229-232
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• 2010

Caffeine and catechins from the Yabukita, Yutakamidori, Saemidori, Okumidori, and Fushun varieties of tea leaves picked during different harvesting seasons from April to October were evaluated using HPLC. Total content of catechins increased greatly with the later harvesting time of tea leaves (i.e., picking the leaves in September versus in April) and decreased slightly after September. Yabukita tea leaves picked in August contained 43.1 mg% catechins including EGC, EC, ECG, and EGCG, with the ECGC levels constituting greater than 50% of those four compounds. Yutakamidori and Okumidori varieties picked in September contained the highest catechin values, at 43.6 mg% and 31.0 mg%, respectively. Fushun and Saemidori varieties contained lower catechin concentrations of 14.5 mg% (July) and 11.7 mg% (August) compared to other varieties. The EGCG levels gradually decreased in the late harvesting season, while levels of the other catechins, EC, EGC, and ECG, gradually increased. All varieties of green tea showed a gradual decrease in caffeine content toward the end of our harvesting efforts in October, with levels of 58～68 mg% in April and 28～57 mg% in October. Yabukita, Saemidori, and Okumidori varieties reached their highest caffeine levels in late spring/early summer, with Yabukita and Okumidori varieties reaching a high of 73.4% and 63.5% caffeine, respectively, in May, and Saemidori at 64.0% in June. In particular, Fushun still contained high caffeine of 66.8 mg% (September) during the late harvesting season.

• 한국식품위생안전성학회지
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• 제17권3호
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• pp.117-123
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• 2002

시중에 유통되고 있는 녹차중의 catechin류에 대하여 열수추출 및 HPLC분석을 통하여 함량을 조사하고 이를 효율적으로 이용하기 위하여 pH조건이 녹차 catechin류의 안정성에 미치는 영향에 대하여 분석하였다. 시판 중인 전남 보성산 녹차의 catechin류 함량은 (+)-catechin>(-)-EGCg>(-)-EGC>(-)-EC>(-)-ECg순으로 추출되었고 Total catechin류의 함량은 103.72mg/g이었다. 녹차에서 분리·정제되어진 catechin류인 (+)-catechin, (-)-EC, (-)-ECg, (-)-EGCg를 pH 3∼11에 대한 안정성을 흡광도측정장치를 이용하여 측정하였다. 그 결과 catechin류의 pH에 대한 영향을 최대흡수파장 및 흡광도 변화로 보면 pH가 높을수록 (+)-catechin과 (-)-EC은 흡광도가 증가되었고 (-)-ECg와 (-)-EGCg는 최대흡수파장이 증가되었다. 또한 7일간 실온에서 저장하면서 기간에 따른 변화를 살펴본 결과에서 산성조건에서는 큰 변화가 없지만 알칼리조건에서는 흡광도가 증가되었다. (+)-catechin과 (-)-EC은 알칼리조건에서 흡수파장 400∼430 nm에서 저장기간이 길수록 흡광도가 증가되었다. 이는 녹차의 갈변과 관계가 있을 것으로 생각되었다. 이상의 결과로, 녹차 Catechin유도체의 pH 및 저장기간에 대한 영향은 ECg, EGCg에 gallic acid의 결합에 의한 것으로 생각되고, C, EC의 불안정은 중합반응으로 생각된다. 녹차 catechin류는 대부분 산성에서 저장기간이 길고 안정한 것으로 나타났으나 생리활성이 강한 (-)-EGCg는 산성에서도 불안정한 것으로 나타났다. 결론적으로 녹차의 기능성 성분을 효율적으로 이용하기 위해서는 pH를 낮게 유지하여야 할 것으로 사료되어진다.