The physiologically advantageous aspects of green tea have been identified recently and green tea has been a favorite drink of many people. Due to the increased awareness of green tea’s positive effects on human health, the demand for foods containing green tea has increased. This has led to the development of diverse green tea-related beverages; thereby many companies in Korea have put a wide variety of manufactured green tea beverages on the market. However, the components within green tea beverages have not been examined in Korea yet. In this study, we investigated the contents of the physiologically functional materials found in green tea, such as catechin, catechin gallate, epicatechin, epicatechin gallate, epigallocatecin gallate, gallocatechin gallate and caffeine. Fifty-six green tea products purchased from the local grocery stores and cafes were analyzed using high performance liquid chromatography (HPLC) analysis. As a result, all tested products contained catechin and caffeine, although the amount of each component was largely different. The total amount of catechin derivatives in the manufactured green tea beverages purchased from cafes was 263.17 mg/L, while they were 61.99 mg/L in the beverages purchased from the local grocery stores. And, to the almost samples the amount of caffeine was proportional to the amount of catechin.

Using green tea(GT), oolong tea(OT), black tea(BT) and green tea bag(GTB) out of tea products in market, this study quantified polyphenol and catechins as anti-oxidant substances and analyzed their respective anti-oxidant capacities. As a result, more epigallocathechin(EGC) was found in GT and GTB as well as caffein(CAF) in GT and BT. GT contained more epigallocathechin gallate(EGCG) than other tea types. Both FRAP and ORAC, as two methods of analyzing anti-oxidant capacities, showed that GTB had highest anti-oxidant capacities, while OT had lowest of all. By brand, it was found that all the 3 brands of GT had similarly high anti-oxidant capacities, but there were differences in the anti-oxidant activities of GTB and BT depending on brand. Out of catechin components, it was found that epicatechin(EC), epicathechin gallate(ECG) and EGCG were major components affecting anti-oxidant capacities.

녹차카테킨은 다양한 생리활성을 지닌 것으로 알려지고 있다. 본 실험에서는 사염화탄소와 갈락토사민으로 유발된 간독성에 대한 녹차카테킨의 간기능보호효과가 연구되었다. 녹차카테킨(50 mg/kg와 100 mg/kg)은 사염화탄소(0.5 ml/kg)와 갈락토사민(400 mg/kg)이 투여되기 전 그리고 투여 후 3일동안 흰쥐에 경구투여되었고, 간기능지표로 AST와 ALT를 측정하였다. 녹차카테킨(50 mg/kg)은 사염화탄소 처리된 랫드에서 상승된 혈중 AST와 ALT활성을 전투여군(262±11, 80±19 에서 153±33, 55±25로)과 후투여군(156±40, 105±3에서 106±22, 55±9로)모두 감소시켰다. 또한 갈락토사민으로 유도한 경우에도 AST와 ALT 수치는 전투석군(576±24, 276±68에서 236±13. 115±13로) 후 투여군(233±54, 137±11에서 119±23, 44±17로)에서 모두 유의성있게 감소된 결과를 나타내었다 또한 간 조직학적 검사에서도 사염화탄소와 갈락토사민으로 유도된 간경변을 유의성있게 억제하였다. 이상의 결과로 볼 때 녹차카테킨은 간독성에 의한 병변을 예방 및 치료할 수 있는 신약후보물질로서의 가능성을 시사한다.

시중에 유통되고 있는 녹차중의 catechin류에 대하여 열수추출 및 HPLC 분석을 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 > (-)-ECg 순으로 추출되었고 Total catechin류의 함량은 103.72 ㎎/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 ㎚에서 저장기간이 길수록 흡광도가 증가되었다. 이는 녹차의 갈변과 관계가 있을 것으로 생각되었다. 이상의 결과로, 녹차 Catechin 유도체의 pH 및 저장기간에 대한 영향은 ECg, EGCg에 gallic acid의 결합에 의한 것으로 생각되고, C, EC의 불안정은 중합반응으로 생각된다. 녹차 catechin 류는 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.

The purpose of this study was to elucidate the effects of green tea catechins (GTC) on the lipid peroxidation and superoxide dismutase (SOD). GTC showed the high SOD activity, while significantly inhibited the peroxide value of linoleic acid (93%) and lipid petoacidation (84%) from rat liver microsomal fraction induced by Fe^(2+)/ascorbate system. The effects of GTC on the SOD and catalase activities, and lipid peroxidation after oral administration were investigated. GTC (50 mg/kg) significantly increased SOD (62%) and catalase activities (75%), while significantly inhibited the lipid peroxidation (52%) of rat liver microsome in a dose-dependent manner. These results suggest that GTC has the antioxidative effect which is related to the prevention of aging and cancer.

This study was carried out to measure the contents of moisture, crude ash, crude fat, total amino acid, with amino acid composition, vitamin C, β-carotene, vitamin E, total catechins, EGCG, EGC, ECG, EC, GA, caffeine, theobromine and theophylline of the green tea I, II, III, oolong, and black tea. The content of crude fat of green tea I, II, III, oolong, and black teas was 1.1, 2.5, 4.9, 0.8 and 1.2% respectively, total amino acid content was 0.87, 0.78, 0.60, 0.63 and 1.05% respectively, and theanine content was 0.52, 0.48, 0.31, 0.41 and 0.61%, respectively. Total amino acid content of green tea increased in the order of green tea I $gt; green tea II $gt; green tea III, and among the teas, the content of theanine was the highest in the amino acids present. The content of vitamin C of green teal, II, III, oolong, and black tea was 101.6, 87.5, 95.9, 99.1 and 108.0 mg%, respectively, β-carotene content was 270, 268, 481, 80 and 181 ppm, respectively. Among the α-, β-, γ- and δ-tocopherol, the content of α-tocopherol was the highest in vitamin E present, and β- and δ-tocopherol were not detected in the samples of green teal, II, III, oolong, and black teas. The total catechins of green teal, II, III, oolong, and black teas was 10.5, 10.4, 7.2, 8.4 and 1.8% respectively, and among them, EGCG content was the highest. The content of EGC increased in the order of green tea I $gt; green tea III $gt; green tea II $gt; oolong tea $gt; black tea. The contents EGCG and ECG increased in the order of oolong tea $gt; green tea I $gt; green tea II $gt; green tea III $gt; black tea, and the highest contents of EGCG and ECG were observed in the samples of oolong tea. The content of GA was 0.01, 0.02, 0.05, 0.13 and 0.31%, respectively, and the highest contents of GA, caffeine and theobromine were observed in the sample of black tea. The highest content of theophylline, however, was observed in the sample of green tea I.

The extraction yield of MeOH extract of green teas, oolong tea and black tea were 3 to 5, 4 to 5, and 5 to 7 fold higher than those of EtOH and EtAC extract, respectively. The amount of total catechins of EtAC extract of the black tea, and of the green teas and oolong tea were three- and two-fold higher than that of EtOH or MeOH extract of the corresponding teas, respectively. The antioxidative activities of EtOH, MeOH and EtAc extract were considerably higher than that of BHT and dl-α-tocopherol at 200 ppm level. The antioxidative activities of EtOH and MeOH extract at 200 and 500 ppm level, and of EtAc extract at 200 ppm level varied depending on the type of tea as follows : green tea I $gt; green tea II $gt; green tea III $gt; oolong tea $gt; black tea. The antioxidative activity increased as the content of EGC increased. But the antioxidative activity of MeOH extract at 1000 ppm level, and of EtAc extract at 500 and 1000 ppm level were not affected by the content of EGC and EGCG.

The objective of this study is to investigate the direct effects of green tea catechins(GTC) on vascular smooth muscle tension and ^(46)Ca^(2+) uptake in rat aorta. The methods used in this study are isometric tension measurements using physiograph, Lanthanum method for ^(46)Cac^(2+) (2 uCi/ml) uptake measurement in rat aorta. GTC modified tension induced by 40 mM KCl or 1 uM norepinephrine in rat aorta. Low concentrations of GTC($lt;0.5 mg/m increased tension by 40 mM KCl or 1 tM norepinephrine, individually. However, high concentrations of GTC($gt; 0.5 mg/ml) inhibited tension by 40 mM KCl or 1 uM norepinephrine, individually. GTC increased ^(45)Ca uptake induced by 40 mM KCl in a dose-dependent manner. From these results, GTC has the dual actions in vascular smooth muscle in vitro. Low concentrations of GTC augments tension by K or norepinephrine. However, high concentrations of GTC inhibits tension by K or norpeinephrine. GTC may have Ca^(2+) channel activation action, which may result in unphysiological vasodilation by Ca^(2+) overload in vascular smooth muscle.

Green tea catechins(GTC) were studied for its inhibitory effect on human platelet aggregation in vitro, for its antithrombotic effect in mice in vivo, and for 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 in vitro. GTC also prevented death due to the formation of pulmonary thrombosis by platelet aggregates in mice in a dose-dependent manner in vivo. 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.

The aim of this study is to investigate the effects of tea catechin on fasting blood glucose in experimental diabetes model. Type 2 diabetes mellitus in rats was induced by high fat diet/low-dose streptozotocin. The experimental group was divided into 3 different groups, non-diabetes control (NC) group, diabetes mellitus (DM) group, and diabetes mellitus+P60 (DM+P60) group. Polyphenon 60(P60) administered with dissolved in 0.2% dringking water. At 16 weeks after P60 treatment, fasting blood glucose, plasma insulin and serum triglyceride levels were measured. The glucose metabolism-related genes were studied in rat liver by RNA-seq analysis. Fasting blood glucose levels increase by four times in the DM group compared to the NC group. In the DM+P60 group, it was decreased by 24% compared to the DM group. The HOMA-IR index was increased in the DM group and it decreased in the DM+P60 group compared to the DM group. The serum triglyceride level increased by 148% in the NC group, and decreased by 22% in the DM+P60 group compared to the DM group. Glucokinase mRNA expression was decreased in the liver of DM group compared to NC group, whereas the phosphofructokinase 1, glucose-6-phosphotase and phosphoenolpyruvate carboxykinase expression did not show significant differences in DM group liver. In DM+P60 group, liver glucokinase expression was increased significantly (P: 5.00E-05) compared with DM group. This study shows that P60 beneficially modifies glucose metabolism and markedly enhances glucose tolerance in experimental diabetic rats. Dietary supplementation with P60 could potentially contribute to nutritional strategies for treatment of type 2 diabetes mellitus.

녹차, 부분발효차, 발효차 및 후발효차 등 다양한 차 제품 분말을 NIRSystem를 이용하여 전 대역(400-2500 nm)에서 스펙트럼을 얻어 중회귀분석에 의해 색상 관련 특성 및 카테킨류 성분에 대한 검량식을 유도하였다. Hunter color scale에서 발효정도의 변이를 a/b로 98.7% 설명될 수 있어 a/b값으로 차제품의 발효정도를 추정할 수 있다. MPLS를 이용하여 작성된 검량식의 결과 L값의 검량식 작성시 결정계수는 0.997, a값의 결정계수는 1.00, b값의 결정계수는 0.996, a/b값의 결정계수는 0.999로 매우 높았다. MPLS를 이용하여 작성된 검량식의 결과 EGC, EC, EGCg, ECg 및 총 카테킨의 결정계수는 각각 0.919, 0.896, 0.978, 0.905 및 0.983으로 매우 높았다. 차 제품 분말의 색상관련 특성들(L, a, b, a/b) 및 카테친류 (EGCg, EGC, EC, ECg 및 총 카테킨) 의 검량식 정확도가 매우 높아서 NIRS의 가시광선 대역(400~700 nm)및 근적외선 대역(780~2500 nm)에서 동시에 두 특성의 성분을 1~2분 내로 측정이 가능하다.

포도씨의 총 카테킨 함량과 추출물의 항산화성을 극대화하기 위한 마이크로웨이브 추출조건의 최적화를 시도하였다. 중심합성계획에 따라 추출조건(microwave power , 에탄올 농도 , 추출시간 )을 설계하고, 종속변수로서 추출물의 수율, 카테킨 함량 및 전자공여능을 회귀 분석함으로써 최적 추출조건을 예측하였다. 모든 회귀식의 는 0.9 이상으로 1% 수준에서 유의성이 인정되었다. 총 카테킨 함량의 최대 추출 값은 434.16 mg%로 예측되었으

지금까지 (-)-epigallocatechin-3-gallate (EGCG)는 인간의 피부에 유용한 녹차 카테킨 중에서 가장 강력한 항산화 성분으로 알려져 왔다. 본 연구팀은 용매, 온도, 압력 등 다양한 조건을 변화시키며, 멸균과정(autoclaving) 중에 발생하는 이성질체화(epimerization) 과정을 연구하여, gallocatechin-3-gallate (GCG) 함량이 크게 증가된 열전환-EGCG-복합체(heat-epimerzied-EGCG-mixture, HE-EGCG-mix)를 순수한 EGCG로부터 조제 하였다. 이러한 열전환-EGCG-복합체는 무모쥐 SKH-1을 이용한 실험에서, 손상된 피부 장벽의 회복 시에 인보루크린 7 (involucrin 7) 단백질의 발현량을 EGCG 처리 시보다 증가시킴을 확인하였다. 또한, in vitro 실험을 통하여 GCG는 PPAR-α에 대한 전이활성(transactivation) 효과가 EGCG보다 뛰어남을 확인하였다. 이러한 결과는 열전환-EGCG-복합체에 함유된 고함량의 GCG 성분에 의해서, 피부 장벽 손상 회복 시 PPAR에 의해 매개된 각질형성세포(keratinocyte)의 분화가 더욱 촉진될 수 있음을 암시한다. 따라서, EGCG의 C-2 에피머(epimer)인 GCG는 녹차 카테킨을 이용한 피부 장벽 개선 용도의 화장품과 건강식품 개발 시 주요 소재로 활용될 수 있다.

차나무 카테킨류의 생산성을 높이기 위하여 차나무 잎의 캘러스 배양시 thiamine-HCl과PVP의 효과를 조사하였다. 캘러스의 생장은 20 mg/L thiamine-HCl이 포함된 캘러스증식배지(0.2 mg/L 2,4-D와 1.0 mg/L TDZ가 첨가된 MS 배지)에서 가장 왕성하여 대조구에 비해 1.7배의 생장을 보였다. 배양된 캘러스의 카페인 함량은 신초에 비해 10%이하로 낮아졌고 총 카테킨류 함량은 40 mg/L thiamine-HCl에서 가장 높아 신초의 1.6배까지 증가하였다. 특히 신초에서는 검출되지 않았던 (-)-epicatechin(EC)이 thiamine-HCl 또는 PVP를 처리하여 배양하였을 경우 모든 처리에서 검출되었으며, (-)-epicatechingallate(ECG)는 신초에서 보다 4.8배나 높은 함량을 나타내었다. 캘러스 생장과 고효율의 카테킨 생산을 고려했을 때 30 mg/L thiamine-HCl이 포함된 배지가 최적의 배양조건으로 판단된다.