• 한국염색가공학회지
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• 제18권6호
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• pp.80-87
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• 2006

Nowadays, interests of ultraviolet(UV) protection increased, since the UV dosage on the earth surface has increased over years. Overdose of UV can cause various skin, eye, and even DNA damages. Therefore, it is need to develop a proper mean to protect human skin and eye from UV radiation. In this study, the UV protective effect of green tea extract dyed fabrics with various fiber types were examined. Green tea has an active moiety called 'catechin' having benzene rings in its structure, which would exert a proper UV protective property. Green tea dyed fabrics showed the increase in UV protection, and silk showed the highest increase in UV protection (from 52.2% to 84.5% in UV-A, from 66.1% to 90% in UV-B). The order of UV-A protection increase is silk, wool, nylon and acrylic, PET, and cotton. The order of UV-B protection increase is silk nylon, wool, acrylic, cotton, and PET. In case of silk and nylon, the UV protection property gradually increased as the concentration of green tea extract increased. As a result, it was proven that green tea extract dyeing can improve UV protection property of dyed fabrics in environment-friendly and biocompatible manners.

• Food Science and Biotechnology
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• 제16권1호
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• pp.167-170
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• 2007

(-)-Epigallocatechin-3-gallate (EGCG), a mai or tea catechin has been shown to have many interesting biological activities. In the present study, we studied the effects of green tea catechins, EGCG metabolites, and black tea theaflavins on accumulation of EGCG in HT-29 human colon cells. Intracellular levels of [$^3H$]-EGCG were not changed significantly in the presence of other tea catechins including (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin-3-gallate. EGCG methyl metabolites and EGCG 4"-glucuronide did not affect cellular levels of [$^3H$]-EGCG. Black tea theaflavins and theasinensin A (TsA), an EGCG oxidative dimer, however, significantly decreased cellular accumulation of EGCG in HT-29 cells by 31-56%. This decrease was more pronounced when cells were incubated in the presence of theaflavin-3',3"-digallate (TFdiG) or TsA. When EGCG was added separately from TFdiG or TsA, the accumulation of EGCG in HT-29 cells was also significantly decreased regardless of when TFdiG or TsA was added during the uptake study (p<0.01). The results suggest that theaflavins and TsA may interrupt EGCG absorption through the gastrointestinal epithelium.

• Biomolecules & Therapeutics
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• 제11권4호
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• pp.238-244
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• 2003

Nicotine is one of the major hazardous components in cigarettc smoke. Nicotine deals a harmful effect to smokers and passive smokers due to its rapid conversion to various carcinogenic metabolites. Nitrosamine-4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is believed to cause lung cancers among the nicotine-derived carcinogens. Recent studies report that NNK synthesis can be inhibited by the metabolism pathway to produce a stable metabolite cotinine from nicotine. Tea polyphenols have been known to contain factors to prevent cancers and to retard progression of cancers. This study aims to correlate tea polyphenol's potential for cancer prevention with an accelerated formation of cotinine. The conversion from nicotine to cotinine in the presence of tea extracts or three polyphenols (Catechin, epicatechin gallate, epigallocatechin gallate) was measured in established cell lines and in Xenopus oocytes. Among three lines of cell used, PLC/PRF5 and HEK293 cells showed a fast turnover from nicotine to cotinine while HepG2 cell line showed a marginal difference between groups treated and non-treated with tea polyphenols. When Xenopus oocytes were microinjected with nicotine, tea polyphenols appear to accelerate the conversion of nicotine to cotinine. Among the polyphenols tested in this study, (＋)－catechin showed the best efficiency overall in accelerating conversion from nicotine to cotinine both in the cell lines and in the oocytes. In summary, the present study indicated that tea polyphenols have a positive effect on conversion of nicotine to cotinine.

• 한국식품영양과학회지
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• 제24권1호
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• pp.154-159
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• 1995

Inhibition of xanthine oxidase by tea extracts obtained from non-fermented tea(steamed green tea and roasted green tea), semi-fermented tea(oolong tea) and fermented tea(black tea) were investigated. The crude catechin fraciton had a hgher inhibitory effect against xanthine oxidase, and the effect was increased with the addition of tea extracts. Their inhibitory effect were hardly influenced until extracted three times with hot water. According to the investigation of catechins in the crude catechin fraction obtained from tea extracts, (-)-epicatechin-(EC), (-)-epicatechin gallate(ECg). (-)-epigallocatechin(EGC) and (-)-epigallocatechin gallate(EGCg) were 80.1$\mu\textrm{g}$/mg 113.5$\mu\textrm{g}$ /mg, 186.3$\mu\textrm{g}$/mg and 367.7$\mu\textrm{g}$/mg in steamed green tea, and 75.6$\mu\textrm{g}$/mg, 114.7$\mu\textrm{g}$/mg, 193.7 $\mu\textrm{g}$/mg and 381.9$\mu\textrm{g}$/mg in roasted green tea, and 69.4$\mu\textrm{g}$/mg, 110.0$\mu\textrm{g}$/mg, 127.1$\mu\textrm{g}$.mg and 464.9$\mu\textrm{g}$/mg in oolong tea, and 78.1$\mu\textrm{g}$/mg, 171.8$\mu\textrm{g}$/mg, 80.7$\mu\textrm{g}$/mg and 51.4$\mu\textrm{g}$/mg in black tea, respectively. Order of the content of these catechins was (-)-EGCg>(-)-EGC>(-)-ECg>(-)-EC in steamed green tea, roasted green tea and oolong tea, and was (-)-ECg>(-)-EGC>(-)-EC>(-)-EGCg in black tea. Also the concentration of catechins was hardly influeced until extracted three times. The inhibition ratio of xanthine oxidase by autherntic catechins was hardly influenced until extracted three times. The inhibition ratio of xanthine oxidase by authentic catechins was 94.9% and 87.6% by addition of 5.0$\mu\textrm{g}$/ml of (-)-EGCg and (-)-ECg, respectively. the inhibitors of xanthine oxidase were supposed to be due to (-)-ECg and (-)-EGCg in tea polyphenol compounds.

• Journal of the Korean Wood Science and Technology
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• 제39권4호
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• pp.370-380
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• 2011

본 연구는 녹차 생잎 채취지의 토양의 성질과 채취시기별(우전-세작-중작) 녹차 생잎에 대한 화학성분 및 무기물 성분을 분석하였다. 먼저 조사지역의 토양의 성질을 살펴보면 대부분이 배수가 양호하고 인산이 풍부한 사양토와 양토로 구성되어 있었다. 녹차 생잎에 대한 성분 분석에 있어서는 섬유질, 탄닌, 비타민 C와 총카테킨 함량은 채취시기가 늦어질수록 증가한 반면 총질소, 총아미노산, 데아닌, 카페인 등은 대체로 감소하는 경향을 보였다. 무기물 함량에 있어서는 채취시기가 늦어질수록 Mg, Ca, Mn은 증가하였으나 Na, K, B는 감소하였다. 그리고 화학성분 중 총질소, 엽록소, 총유리아미노산, 데아닌, 카페인, 총카테킨과 무기물 중 나트륨, 마그네슘, 칼슘, 붕소, 세레늄에 있어서는 우전과 세작 간에 거의 함량 차이를 보이지 않았다.

• 한국식품과학회지
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• 제36권4호
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• pp.542-546
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• 2004

국내산 녹차의 채엽시기가 녹차 중의 카테킨, 카페인, 아미노산 및 무기질 함량과 조성에 미치는 영향에 대하여 조사하였다. 녹차의 총 카테킨 함량은 40.61-52.04mg/g으로 채엽시기가 늦을수록 증가하였으며, 카테킨 조성은 채엽시기에 관계없이 EGC, EGCg, EC, CC, ECg, C, GCg 및 Cg의 순으로 함유되어 있음을 알 수 있었다. 카테킨류 중 기능성 작용이 우수한 EGC 및 EGCg는 전체의 50% 이상을 차지하였고 온화한 떫은맛으로 후미에 감미를 남기는 유리형 카테킨인 EC와 EGC는 전체의 53.21%에서 57.09%를 차지하였다. 카페인 함량은 4월차 17.56mg/g, 5월차 15.71mg/g, 6월차 14.92mg/g 및 7월차 14.61mg/g으로 채엽시기가 늦을수록 감소하는 경향을 나타냈다. 총 아미노산 함량은 4월차 45.84mg/g, 5월차 22.64mg/g, 6월차 12.22mg/g 및 7월차 10.45mg/g으로 채엽시기가 늦을수록 감소하였으며 특히, 중요한 생리적 기능을 갖는 theanine의 감소 폭이 큰 것으로 타났다. 무기질 함량은 채엽시기가 늦어질수록 Fe, Mn 및 Mg는 증가하였으며, Cu는 감소함을 알 수 있었다.

• 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.

• 한국재료학회지
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• 제33권11호
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• pp.458-464
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• 2023

In order to develop catechin patches for skin regeneration at wound sites, patches with varying concentrations of catechin and chitosan were manufactured. An optimal composition ratio was determined by adjusting the drug release rate and amount, to maximize efficiency. The catechin used in this study was extracted from green tea leaves using a solvent/ultrasonication method, and its characteristics were confirmed through Fourier transform-infrared spectroscopy (FT-IR) and high-performance liquid chromatography (HPLC) analyses. Patches were prepared with different concentrations of catechin and chitosan, and various properties were analyzed using techniques such as FT-IR, water contact angle analysis, and UV-Vis spectroscopy. It was observed that as the chitosan concentration increased, the release of catechin slowed down or almost ceased. A patch manufactured with 1.5 mg/cm² of catechin at a 1 % chitosan concentration exhibited a high initial release rate over 24 h and demonstrated cellular biocompatibility. Consequently, these patches, with tailored release characteristics based on the concentrations of chitosan and catechin, hold promise for use as drug delivery systems in wound healing applications.

• 한국식품영양과학회지
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• 제26권6호
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• pp.1187-1193
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• 1997

The purpose of this study was to investigate the effects of green tea catechin on lipid metabolism in streptozotocin(STZ)-induced diabetic rats. Male Sprague-Dawley rats weighing 150$\pm$10gm were randomly assigned to one normal and three STZ-induced diabetic groups. Diabetic animals were fed catechin free diet(DM-0C group), 0.5% catechin diet(DM-0.5C group) and 1% catechin diet(DM-1C group). Diabetes was experimentally induced by intravenous injection of 55mg/kg body wt of STZ in citrate buffer(pH 4.3) after feeding of three experimental diets for 4 weeks. Animals were sacrificed at the 6th day of diabetic states. Levels of blood glucose were three fold higher in all three STZ-induced diabetic groups than that of the normal group. The levels of plasma insulin were markedly lower in three STZ-induced diabetic groups than that of the normal group. The levels of plasma cortisol were increased in DM-0C group compared with that of the normal group. Triglyceride, total-cholesterol and LDL-cholesterol levels in serum were increased in DM-0C groups compared with the normal group but were not significantly different between catechin diet groups and normal group. Serum HDL-cholesterol levels were reduced in DM-0C and DM-0.5C groups by 38% and 25%, respectively and had similar tendency in the DM-1C group compared with that of control group. Atherogenic index have shown same pattern as the result of total cholesterol. Activities of 3-hydroxy-3-methylglutaryl Co enzyme A(HMG-CoA) reductase were higher in DM-0C groups than those of the normal group but were not significantly different between catechin diet groups and the normal group. It is concluded that dietary catechins can modulate lipid levels of serum and liver HMG-CoA reductase activity in diabetic rats.

• 한국식품영양과학회지
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• 제41권7호
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• pp.936-942
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• 2012

본 연구에서는 흰쥐에 마이크로웨이브를 조사한 후 폐조직을 대상으로 폐조직 기능장애를 일으키는데 주된 역할을 하는 혈전생성능을 arachidonic acid(AA) cascade계를 통해 관찰하여 마이크로웨이브에 의한 폐혈관 기능장애와 그에 대한 녹차 catechin의 항혈전 효과를 규명하고자 하였다. 실험군은 마이크로웨이브를 조사하지 않은 정상군과 마이크로웨이브를 조사한 군으로 나누고 마이크로웨이브 조사 군은 다시 식이 중 catechin 공급수준에 따라 catechin을 넣지 않은 군(MW group), catechin을 0.25% 급여한 군(MW-0.25C group), catechin을 0.5% 급여한 군(MW-0.5C group)으로 나누었다. 식이와 음료는 자유 섭식시키면서 2주간 사육한 후 2.45 GHz 대역의 주파수를 15분간 1회 조사하였으며 마이크로웨이브 조사 후 6일째 동물을 희생시켜 본 실험에 사용하였다. 실험군의 실험동물 수는 각각 10마리로 실험하였다. $PLA_2$ 활성은 마이크로웨이브 조사로 30% 증가하였으며 MW-0.25C군은 15% 증가였으나 MW-0.5C군은 정상군 수준이었다. 인지질분자종의 변화를 관찰한 결과 lyso PE가 MW군에서 47% 증가되었으나 MW-0.25C군 및 MW-0.5C군에서는 각각 18%, 20% 증가되었다. $TXA_2$ 생성은 MW군에서 50%의 현저한 증가를 보였으나 catechin 공급군인 MW-0.25C군 및 MW-0.5C군은 정상군 수준이었다. $PGI_2$ 생성은 MW군에서 31%의 유의적인 감소를 보였으나 catechin 공급군인 MW-0.25C군 및 MW-0.5군은 정상군 수준이었다. 따라서 혈전생성지표인 $PGI_2/TXA_2$ ratio는 정상군에 비해 MW군에서 43% 유의적으로 감소되었으나 MW-0.25C군 및 MW-0.5C군은 정상군 수준이었다. 지질과산화물의 함량은 MW군에서 34% 유의적으로 증가하였으며 catechin 공급군은 정상군 수준이었다. 결론적으로 마이크로웨이브에 피폭된 흰쥐 폐조직에서는 AA cascade계의 율속 효소인 $PLA_2$ 활성의 증가와 혈전생성지표로 인식하는 $PGI_2/TXA_2$ ratio의 불균형이 초래되었으나 catechin은 TBARS 농도를 낮추면서 $PLA_2$ 활성을 저해시키고 AA cascade계를 개선시킴으로써 항혈전 작용을 나타내었다.