• Korean Journal of Pharmacognosy
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• v.10 no.2
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• pp.41-53
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• 1979

A 6', 8a-bonded catechin dimer was synthesized by action of phenoloxidase on 2mol (+)-catechins. The same dimer and other two dimers which are also 6', 8a-bonded were isolated from the fresh cortex of Quercus robur. The 4, 8a-bonded and the etherified 4, 8a-bonded dimers were isolated from it. It was discussed about the meaning of the enzymatically produced 6', 8a-bonded dimers in plant cell. The isolated dimers are as following: 1. 6', 8a-bonded dimers: (+)-catechin-(+)-catechin-6', 8a-dimer(IX), (+)-catechin-(+)-gallocatechin-6', 8a-dimar (XIII), (+)-gallocatechin-(+)-catechin-6', 8a-dimer(XIV). 2. 4, 8a-bonded dimers: (+)-catechin-(+)-catechin-4, 8a-dimer(X), (-)-epicatechin-(+)-catechin-4, 8a-dimer (XI), (+) -galloatechin-(+)-catechin-4, 8a-dimer (XII). 3. 4,8a-bonded dimers with ether linkage: etherified(+)-catechin-(+)-catechin-4, 8a-dimer (XV), etherifid (+)-catechin-(+)-gallocatechin-4, 8a-dimer (XVI), etherified (+)-gallocatechin-(+)-catechin-4, 6a-dimer (XVII).

• Journal of Food Hygiene and Safety
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• v.16 no.2
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• pp.117-124
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• 2001

The main constituent of green tea, catechins have been reported to have numberous biological anti-vites including antimutagenic, antibacterial, hypocholesterolemic, antioxidant and antitumor properties. In the present study, we examined the protective effect of catechin on UVB-induced skin damage. Catechin (3 mg/mouse) was topically treated to dorsal area of SHK-1 hairless mouse daily for 2 weeks. UVB (100 mJ/$\textrm{cm}^2$) was also treated soon after application of catechin alone or with catechin for 2 weeks. Catechin reduced UVB-induced infiltration of inflammatory cells, fibrosis of cells and collagen-fiber formation. In addition, catechin also prevented UVB-induced DNA fragmentation and apoptosis cell number, but not changed p53 level. Furthermore catechin inhibited UVB-induced cell proliferation. There results showed that catechin have preventive effect aganinst UVB-induced skin damages. and these effects could contribute to the antitumor promoters activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.3
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• pp.284-288
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• 1983

This experiment was carried out to investigate the stability of ascorbic acid (AsA) in the mixed solution of AsA and catechin according to the content changes of AsA and catechin under boiling, and for the respective concentration and pH. The loss of AsA was most for 10 minutes of boiling and accelerated by the mixture of catechin, but the loss was less in the high mixture rate than in the low the loss of catechin most for 10 minutes of boiling, also as the concentration of AsA becomes higher but that of cathchin lower, and as that of AsA lower but that of catechin higher, the loss of catechin becomes less moreover in the case of the low content ratio of catechin, the stability of AsA was better in order of the pH 4, pH 5, pH 6, namely as the pH increased, but in the case of the high better in order of the pH 6, pH 5, pH 4, that is as in decreased.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.6
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• pp.1580-1584
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• 2005

Antioxidative activities of catechin from green tea extracts were examined by the methods of 1,1-Diphenyl-2-picrylhydrazyl (DPPH) electron donating ability, hydroxy scavenging activity and the inhibitory effect on xanthine oxidase activity. The resulted demonstrated the fact that Catechin one (containing Green tea extracts plus catechin 51%) of green tea extracts product showed at 65.5% in electron donating activity on the DPPH. The electron donating ability on the DPPH of Catechin one was increased to 10% than purified catechin. Catechin one showed the activity at 64.5% in scavenging activity using hydroxy radical method. To the Catechin one provided to increase the hydroxy scavenging activity up to 3 fold. Inhibitory effects of the catechin one measured with xanthine oxidase method was 6.5%. Although the antioxidative activity of catechin (98% purified) was lower than that of Catechin one (containing Green tea extracts plus catechin 51%) in same catechin concentrations ($5{\mu}g$, respectively). Therefore, we may suggest that Catechin one can be used as a functional food additive possessing the potent antioxidative activity.

• Korean Journal of Materials Research
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• v.33 no.11
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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.

• Journal of Nutrition and Health
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• v.34 no.8
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• pp.881-886
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• 2001

The purpose of this study was to Investigate the effects of green tea catechin on changes of mineral contents in chronic cadmium-poisoned rats. Sprague-Dawley male rats weighing 100 $\pm$ 10g were randomly assigned one of normal group and three cadmium poisoned groups. Cadmium groups were classified to catechin free diet(Cd-0C group), 0.25% catechin diet(Cd-0.25C group) and 0.5% catechin diet(Cd-0.5C group) according to the levels of catechin supplement. Animals were raised for 20 weeks. Cadmium was supplied in drinking water which contained 50ppm Cd$^{2+}$. Effects of catechin were analyzed on changes of mineral contents in chronic cadmium poisoned rats by determining the calcium accumulation in bones, blood, urine and faces and phosphorus In blood and urine. Cd-poisoning inducted the decrease of red blood cell(RBC), white blood cell(WBC), contents of blood hemoglobin and hematocrit, but the levels of those indices were increased by catechin supplementation. The contents of tibia and femur in Cd-0C group was significantly lower than in normal group, but those of catechin supplemetation group was similar to normal group. The calcium contents of urine and faces were higher in Cd-poisoned groups than in normal group, but they was lowered by catechin supplementation. The phosphorus contents of blood and urine in Cd-0C group was significantly lower than in normal group, but that of catechin supplementation group was similar to normal group. Catechin supplementation improved the calcium metabolism in chronic cadmium poisoned rats by increasing the contents of minerals such as calcium and phosphorus in blood and femur and by lowering the urinary and fecal calcium.m.

• Journal of Nutrition and Health
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• v.33 no.7
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• pp.725-732
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• 2000

The purpose of this study was to investigate the effects of green tea catechin on renal dysfunction and blood presure change in chronic cadmium poisoned rats. Sprague-Dawley male rats weighing 100$\pm$10g were randomly assigned to one normal group and three cadmium poisoned groups. Cadmium groups were classified to catechin free diet(Cd-0C group) 0.25% catechin diet(Cd-0.25C group) and 0.5% catechin diet(Cd-0.5C group) according to the levels of catechin supplement. Animals were raids for 20weeks. Cadmium were supplied as drinking water of 50ppm Cd2+ Morphological changes shown through a light microscope and an electro-microscope revealed the mitochondria and tubule epithelial cell edema in Cd -0C group but they were alleviated in catechin supplementation. The urinary $\beta$2-microglobulin that measured to observe the glomerular injury were higher in Cd-poisoned groups than in normal group but they was lowered by catechin supplementation. Glomerular filtration ratios(GFR) in Cd-poisoned groups were significantly lower than in normal group but that of catechin supplementation group was similar to normal group. This suggested that catechin protected the kidney from the functional damage. Angiotensin converting enzyme(ACE) activity and blood pressure(BP) in Cd-poisoned groups were significantly higher than in normal group. Heart rate was tended to increase in Cd-poisoned groups. The results indicate that green tea catechin supplementation on chronic cadmium-poisoned rats normalized the renal dysfunction and blood pressure system.

• Journal of Nutrition and Health
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• v.34 no.4
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• pp.384-392
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• 2001

The purpose of this study was to investigate the effects of green tea catechin on the cadmium accumulation in body, cadmium excretion and detoxification functions in chronic cadmium poisoned rats. Sprague-Dawley male rats weighing 100$\pm$10g were randomly assigned to one normal group and three cadmium poisoned groups. Cadmium groups were classified to catechin free diet (Cd-0C group), 0.25% catechin diet(Cd-0.25C group) and 0.5% catechin diet(Cd-0.5C group) according to the levels of catechin supplement. Animals were maintained on 0, 0.25 and 0.5% catechin diets for 20 weeks and simultaneously administered 50ppm Cd(sup)2+ dissolved in the drinking water. Body weight, food intakes and food efficiency ratio in Cd-0C group was lower than the normal group. The accumulation of cadmium in rat liver, kidney, and blood was reduced by catechin supplementation. The excretion of cadmium in urine and feces was increased by catechin supplementation. The metallothionein(MT) contents in liver and kidney were increased in all cadmium groups compared with that of normal group. The ratios of cadmium absorption and retention ratios were significantly decreased in catechin supplementation groups. Accordingly, catechin supplementation resulted to an excretion of cadmium in urine and feces and a lowered accumulation of cadmium in liver and kidney by increasing methallothionein synthesis that led to the significant decrease in cadmium absorption and retention ratios.(Korean J Nutrition 34(4) : 384~392, 2001)

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3443-3447
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• 2011

The spectroscopic behavior of catechin (5,7,3',4'-tetrahydroxyflavan-3-ol), has been studied in the presence and the absence of air using UV-vis absorption spectrophotometry and fluorescence spectroscopy. The UV-vis absorption spectrum of catechin shows a very sharp and strong absorption maximum peak at 275 nm in deaerated water. New absorption maximum peaks appeared in aerated water, as well as in basic aqueous solution, caused by the oxidation of catechin. The absorbances in the UV-vis absorption spectrum of catechin decreased when the solution was left in the dark for a long time. The fluorescence emission spectrum of catechin after a long time period differs markedly from that in freshly prepared solution; the fluorescence maxia shifted as time passes after adding catechin to the solutions. When the deaerated basic catechin solutions were left in the dark for a long time, their fluorescence quantum yields were found to be nearly zero. This suggests that the oxidized catechin molecules were seen to have slowly undergone successive chemical reactions in basic buffer solution.

• Archives of Pharmacal Research
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• v.12 no.3
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• pp.219-222
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• 1989

Cartechin and catechin glycoside named uldavioside A were isolated from the Korean folk medicine Ulmus davidiana. Based on chemical and physicochemical evidences, their structure have been determined as (+) catechin (1) and (+)-catechin-5-0-$\betha$ D-apiofuranoside (2).