• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.111-111
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• 2003

Green tea have been widely reported as functional foods because of their various bioactivities. In the present study, we used 3T3-Ll cells model of white adipocytes to clarify whether green tea and its main pharmaceutically effective compounds (EGCG, caffeine and theanine) prevent obesity. Cellular viability, glycerol-3-phosphate dehydrogenase activity, glycerol release and HSL mRNA levels were checked. Glycerol release into the medium was significantly increased by the cells treated with green tea extract. Glycerol release into the medium was significantly increased by the cells treated with green tea extract. Caffeine and theanine from green tea showed some level of lipolytic activity, and glycerol-3-phosphate dehydrogenase activity was remarkably decreased by EGCG. These results suggest that green tea has anti-obesity effect through inhibition of adipogenesis and stimulation of lipolysis. Catechins and theanine of green tea might be the factors responsible for the modulation of lipid metabolism and adipocyte differentiation.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.720-724
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• 2011

Differences in sensory evaluation, physicochemical properties and antioxidant activities between green tea concentrations and tannase-treated green tea concentrations were measured in this study. The results showed that pH did not differ dependent on tannase treatment but antioxidant ability were slightly increased through tannase treatment without significant($p$ <0.05). However, the turbidity of the tannase-treated green tea concentration had significant difference to the non-treated concentration. The astringency, tested via sensory evaluation, decreased significantly after tannase treatment($p$ <0.05). Traces of epicatechin gallate(ECG) and epigallocatechin gallate(EGCG) also disappeared after the tannase treatment, due to the fact that the ester linkages in the catechin structure were broken by the tannase. It was concluded that tannase treatment of tea products is a very effective process for decreasing astringency and turbidity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.2 s.57
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• pp.117-121
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• 2006

Although many studies have been performed to elucidate the molecular consequence of factors that regulate skin aging, little is known about the effect of green tea catechins except EGCG. The matrix metalloproteinase (MMP), can degrade matrix proteins and results in a collagen deficiency in photodamaged skin, are known to play an important role in photoaging. This study, investigated the effects of green tea catechins on the UVA-induced MMP-1 expression, activity of MMP-2 and synthesis of type I procollagen in human dermal fibroblasts. We examined eight catechins that naturally exist in green tea leaves and compared their efficacies among them. Most of catechins inhibited the expression of MMP-1 in dose dependent manner, and the levels were reduced, especially, 57.4 and 68.2% by treatment with $1{\mu}M$ of epigallocatechin-3-gallate (EGCG) and gallocatechin-3-gallate (GCG), respectively. Also, catechins significantly suppressed the activities of MMP-2. Catechins also induced the expression of type I procollagen, however, they acted only at the concentration below $1{\mu}M$ interestingly. Furthermore, when EGCG:GCG:ECG had the ratio of 0.5:1.5:.1.3, they presented the most effective on procollagen synthesis. Therefore, we concluded that catechins significantly inhibited MMPs and induced collagen synthesis. Taken together, all these results suggested that green tea catechins might be good natural materials act as an anti-photoaging and a skin-aging improving agent.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.542-546
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• 2004

Changes in contents of catechins, caffeine, free amino acids, and minerals in green tea loaves according to harvest periods were compared. Total catechin content increased from 40.61 to 52.04 mg/g, while that of caffeine decreased from 17.56 to 14.61 mg/g according to harvest periods. Regardless of harvest periods, composition of catechins was epigallocatechin (EGC)>epigallocatechin gallate (EGCg)>epicatechin (EC)>gallocatechin (GC)>epicatechin gallate (ECg)>catechin (C)>gallocatechin gallate (GCg)>catechin gallate (Cg). Free amino acid content in green tea leaves was highest in young loaves, and gradually decreased according to harvest periods. Theanine content was markedly decreased with leaf aging, suggesting taste of green tea may be changed from mild to bitter with increasing harvest period. Analyses of mineral elements in green tea leaves showed that Fe, Mn, and Mg increased with leaf aging, while Cu showed opposite trend. Results reveal that content of some chemical compounds in Korean (Posong) green tea was highly dependent on harvest period.

• Preventive Nutrition and Food Science
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• v.7 no.3
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• pp.327-331
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• 2002

Tea is a pleasant, popular and safe beverage in the world. During the past decade, epidemiological studies have shown that tea catechins intake is associated with lower risk of cardiovascular disease. Tea provides a dietary source of health-promoting components to help humans reduce a wide variety of cancer risks and chronic diseases. The antioxidative activity of tea-derived catchins has been extensively studied. The antioxidant effect is a synergistic action between catechins e.g. EGCG, EGC, ECG, EC, pheophytins a and b, and other components in tea leaves, which aye more bioavailable for human body. Green tea has a Higher content of catechins than other kinds of tea. Green tea extract with hot water has high potential and more efficiency to reduce cancer risk than any other tea products or pure EGCG. Protein, iyon, and other food components may interfere with the bioavailability of ten catechins. Interaction of catechins with drug affects the cancer-preventive activity of some cancer-fighting medication. Further studies are required to determine the bioavailability of tea catechins and cancer-preventive functionality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.9
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• pp.1328-1332
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• 2011

This study was carried out to investigate changes in epigallocatechin gallate (EGCG) contents and antioxidant activity of duck egg after pressurized soaking in green tea extract. The duck eggs were soaked in different concentrations of green tea extract (10~30%) and subjected to pressures of 0.1~5.0 MPa for 30 min at ambient temperature in a lab model high-pressure rig. After pressured treatment at 5.0 MPa in 30% green tea extract, EGCG content of duck egg white (20 mg/100 g) markedly increased compared to that of untreated sample (0.17 mg/100 g). Moreover, the antioxidant, hepato-protective, and cellular antioxidant activities of duck egg white after pressured treatment at 5 MPa in 30% green tea extract were all higher than those of untreated sample. Our results could have a direct impact on duck egg consumption by increasing consumer awareness of the health benefits of duck eggs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.160-168
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• 1995

Desmutagenicities against 2-amino-1-methyl-6-phenylimidazo[4, 5-b] pyridine(PhIP) and 2-amino-3, 8-dimethylimidazo[4, 5-f]quinoxaline(MelQx) of tea extracts (steamed green tea, roasted green tea, oolong tea and black tea) were investigated. All the fractions obtained from tea extracts showed strong desmutagenic activity against PhIP and MeIQx toward S. typhimurium TA 98 in the presence of the S-9 mix. The crude catechin fraction exhibited the strongest desmutagenic activity. Among these tea extracts, black tea especially exhibited the strongest desmutagenic activity and the activity was 70.9~91.0% against PhIP and 92.2~98.8% against MelQx at a concentration(0.5~1.0mg/plate) for drinking. The activity of authentic catechins of (-)-EGC, (-)-EGCg, (-)-ECg and (-)-EC were 79.5%, 60.2%, 46.1% and 43.5% against PhIP, and were 52.3%, 11.6%, 8.2% and 22.1% against MelQx by addition of 1.0mg/plate, respectively. The desmutagenic activity was supposedly due to the (-)-EGCg, (-)-EGC and (-)-EC in tea polyphenols, and the browning materials. The desmutagenicity was stronger when mutagens were preincubated with S-9 mix after reaciton with black tea extracts than when preincubated with them after reaction with S-9 mix. The desmutagenicity of tea extracts was rather expressed by reacting directly with mutagens than by deactivating the activated forms of mutagens.

• Archives of Pharmacal Research
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• v.28 no.8
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• pp.914-922
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• 2005

The present study was designed to examine the effects of green tea extract (CUMC6335) and epigallocatechin gallate (EGCG) on secretion of catecholamines (CA) in the isolated perfused rabbit adrenal gland. In the presence of CUMC6335 $(200 {\mu}g/mL)$ into an adrenal vein for 60min, CA secretory responses evoked by ACh (5.32 mM), high $K^+$ (56 mM), DMPP $(100{\mu}M \;for\;2min)$, and Bay-K-8644 $(10{\mu}M\;for\;4min)$ from the isolated perfused rabbit adrenal glands were greatly inhibited in a time-dependent fashion. However, EGCG $(10{\mu}g/mL)$ did not affect CA release evoked by ACh, high $K^+$, and Bay-K-8644. CUMC6335 itself failed to affect basal catecholamine output. Taken together, these results demonstrate that CUMC6335 inhibits CA secretion evoked by stimulation of cholinergic nicotinic receptors, as well as the direct membrane depolarization from the isolated perfused rabbit adrenal gland. It is thought that this inhibitory effect of CUMC6335 may be due at least in part to the blocking action of the L-type dihydropyridine calcium channels in the rabbit adrenomedullary chromaffin cells, which is relevant to the cholinergic nicotinic blockade. It seems that there is a big difference in mode of action between CUMC6335 and EGCG.

• Textile Coloration and Finishing
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• v.18 no.1
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• pp.10-19
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• 2006

Despite several recent attempts to measure the concentration of individual catechins by HPLC, it has not been so easy to separate catechins accurately. The aim of the present work is to provide a proper condition for separating each component of catechins by HPLC analysis, and also to evaluate the experimental variables including color differences, and metal ion contents after dyeing and mordanting. Four kinds of Catechins, (-)-epicatechin(EC), (-)-epicatechin gallate(ECG), (-)-epigallocatechin(EgC), (-)-epigallocatechin gllate(EgCG) were isolated from the residues after dyeing. Catechins in Korean green tea leaves are richer when e tea leaves are younger. Higher concentration of catechins owes it to e way it is processed. The contents of catechins adsorbed in silk fabrics after dyeing were in order of EGCG>ECG>EGC>EC. We have found $68\%$ uptake of EGCG, and 116.8mg of EGCG in the silk fabrics after it was dyed with $1\%$ Korean green tea extracts. The absorbance intensity and K/S values of dyed silk fabrics were increased with dyeing temperature and time. Only the surface color of the silk fabric dyed with green tea extracts was yellowish red, but it changed from yellowish red to red with an increase in the mordant concentration. Post-mordanted silk fabrics with ferrous sulfate changed from yellowish red to red and purple color shade. In a practical evaluation, there is no significant change in color after twenty times of the continuous dry cleaning process. However, post-mordanted fabrics with ferrous sulfate faded the brightness of color after dry cleaning. Dyeing silk fabrics with a Korean tea extract reduced the metal ion contents in the silk fabrics when compared to the untreated silk fabrics. Metal contents in silk fabrics dyed and post-mordanted with $1\%$ each metal solution were 0.194 ppm for Aluminum, 1.601ppm for Copper, and 0.334 ppm for Iron. After the post-mordanting process, the heavy metal ion absorption increased, which was mainly attributed to the catechins and polyphenols in dyed silk fabrics.

• Advances in Traditional Medicine
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• v.8 no.2
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• pp.171-177
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• 2008

Epigallocatechin 3-gallate (EGCG), one of the major catechins of tea, was isolated from the decaffeinated, crude methanolic extract of Indian green tea (Camellia sinensis L. O. Kuntze) using chromatographic techniques. EGCG was then screened for antidiarrhoeal activity against 30 strains (clinical isolates) of V. cholerae, which is a well known Gram negative bacillus functioning as the pathogen of cholera. V. cholerae strains like V. cholerae 69, 71, 83, 214, 978, 1021, 1315, 1347, 1348, 569B and ATCC 14033 were inhibited by EGCG at a concentration of $25\;{\mu}g/ml$ whereas V. cholerae 10, 522, 976 were even more sensitive, being inhibited at $10\;{\mu}g/ml$ level. However, V. cholerae DN 16, DN 26, 30, 42, 56, 58, 113, 117, 564, 593, 972 and ATCC 14035 were inhibited at $50\;{\mu}g/ml$ level of EGCG. Only four strains were inhibited at $100\;{\mu}g/ml$. In this study the isolated compound was found to be bacteriostatic in its mechanism of action. In the in vivo experiment using the rabbit ileal loop model two different dosages of EGCG ($500\;{\mu}g/ml$ and $1,000\;{\mu}g/ml$) were able to protect the animals when they were challenged with V. cholerae 569B in the ileum.