• Korean Journal of Plant Resources
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• v.20 no.1
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• pp.38-42
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• 2007

The present study was conducted to investigate the translocation of polyphenols, especially catechin derivatives, from mushroom medium mixed with green tea residues into fruiting body of Pleurotus eryngii. Pleurotus eryngii was grown on the media incorporated by mixing or surface-treated with dry materials including leaf petioles and young stems or leaves of green tea. The dry materials treated in medium did not affect plant height and fresh weight of Pleurotus eryngii body. From the samples of Pleurotus eryngii, the eight main catechin derivatives (-)-gallocatechin(GC), (+)-catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), (-)-gallocatechin gallate (GCG), (-)-epicatechin gallate (ECG), and (-)-catechin gallate (EGCG), and caffeine were analyzed quantitatively by HPLC. The results showed that EGC in Pleurotus eryngii was 45% more detected, when incorporated with the dry materials, than untreated control. Especially, content of EGCG was increased in surface-treated Pleurotus eryngii up to 3.2 ppm, while it was not detected or reduced in control and other treatments. Caffeine content was greatly increased regardless of treatment method, compared with control (0.1ppm), showing 44 fold-amount in Pleurotus eryngii at early growth stage when incorporated with the dry materials into medium. The results indicates that functional catechin derivatives of green tea would be partly translocated into Pleurotus eryngii throught incorporation and surface treatment with residues of green tea plants.

• 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.

• 대한치주과학회:학술대회논문집
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• 2004.11a
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• pp.153-154
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• 2004

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.314.1-314
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• 1998

No Abstract, See Full Text

• Proceedings of the Korean Society of Applied Pharmacology
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• 2002.07a
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• pp.198-198
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• 2002

• Food Science and Biotechnology
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• v.15 no.5
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• pp.799-804
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• 2006

Ingestion of green tea has been shown to decrease prostaglandin $E_2$ levels in human colorectum, suggesting that tea constituents modulate arachidonic acid metabolism. In the present study, we investigated the effects of four purified green tea catechins, (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epigallocatechin-3-gallate (EGCG), and (-)-epicatechin-3-gallate (ECG), on the catalytic activity of cytosolic phospholipase $A_2$ ($cPLA_2$) and release of arachidonic acid and its metabolites from intact cells. At $50\;{\mu}M$, EGCG and ECG inhibited $cPLA_2$ activity by 19 and 37%, respectively, whereas EC and EGC were less effective. The inhibitory effects of these catechins on arachidonic acid metabolism in intact cells were much more pronounced. At $10\;{\mu}M$, EGCG and ECG inhibited the release of arachidonic acid and its metabolites by 50-70% in human colon adenocarcinoma cells (HT-29) and human esophageal squamous carcinoma cells (KYSE-190 and 450). EGCG and ECG also inhibited arachidonic acid release induced by A23187, a calcium ionophore, in both HT-29 and KYSE-450 cell lines by 30-50%. The inhibitory effects of green tea catechins on $cPLA_2$ and arachidonic acid release may provide a possible mechanism for the prevention of human gastrointestinal inflammation and cancers.

• Biomedical Science Letters
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• v.15 no.2
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• pp.127-133
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• 2009

This study was designed to investigate the effects of high concentration of (-)-epigallocatechin-3-gallate(EGCG) on the neuronal activity of rat substantia nigra dopaminergic neurons. Sprague-Dawley rats aged 14 to 16 days were decapitated under ether anesthesia. After treatment with pronase and thermolysin, the dissociated dopaminergic neurons were transferred into a chamber on an inverted microscope. Spontaneous action potentials and potassium currents were recorded by standard patch-clamp techniques under current and voltage-clamp modes respectively. 18 dopaminergic neurons(80%) revealed inhibitory responses to 40 and 100 ${\mu}M$ of EGCG and 4 neurons(20%) did not respond to EGCG. The spike frequency and resting membrane potential of these cells were decreased by EGCG. The amplitude of afterhyperpolarization was increased by EGCG. Whole potassium currents of dopaminergic neurons were increased by EGCG(n=10). These experimental results suggest that high concentration EGCG decreases the neuronal activity of the dopaminergic neurons by altering the resting membrane potential and afterhyperpolarization.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2004.04a
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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.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.932-938
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• 2009

Browning of tea infusion is an obstructive factor influencing shelf life of ready-to-drink green tea. Effects of temperature and illumination on the browning of green tea infusion were investigated. It was shown that both elevated temperature and illumination led to the browning of green tea infusion, but temperature had greater effect on infusion color and level of catechins than illumination. The levels of unoxidized catechins such as (-)-epigallocatechin gallate (EGCg), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), (-)-epicatechin (EC), and total catechins remaining in the tea infusion were significantly correlated to color parameters of the tea infusion. Sodium ascorbate inhibited the infusion browning by suppressing the oxidation of tea catechins and it is considered to be a more suitable preservative for prolonging shelf life of ready-to-drink green tea than ascorbic acid because it has less effect on tea taste. The effects of temperature and illumination on the epimerization of catechins were also discussed.

• Korean Journal of Medicinal Crop Science
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• v.15 no.5
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• pp.319-323
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• 2007

Wild grapes have been used as traditional medicinal use and alcoholic beverage production in Korea. The objective of this study is to improve antioxidant properties in Sae-muru by far infrared ray (FIR) treatment, with expecting potential benefits of FIR treatment for wild grape products during manufacturing processes. FIR treatment in berries induced increased content of catechin, epicatechin gallate, epigallocatechin gallate, gallic acid, rutin, ellagic acid, and resveratrol, while content of epicatechin and epigallocatechin was decreased. Although FIR treatment resulted either increased or decreased chemical component groups, presenting in HPLC chromatograms, antioxidant activity in Sae-muru extract was significantly increased by the FIR treatment. Our results suggest that FIR treatment should be an efficient process in the production of high content of bioactive molecules in Sae-muru.