• Journal of Pharmaceutical Investigation
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• v.29 no.3
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• pp.179-184
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• 1999

Phannacokinetics of epigallocatechin gallate(EGCG) was studied following i.v. bolus and oral administration in rats. The values of systemic clearance(CL) were $67.9{\pm}5.2$ and $26.5{\pm}1.4\;ml/min/kg$ following i.v. bolus administration of 1 mg and 5 mg EGCG, respectively. The values of volume of distribution at steady state (Vss) were $380{\pm}56$ and $835{\pm}84\;ml/kg$ after i.v. bolus administration of 1 mg and 5 mg EGCG, respectively. The decrease in the value of CL and the increase in the value of $V_{ss}$ as a function of EGCG dose (1 mg to 5 mg) suggest saturable mechanism(s) responsible for the distribution and elimination of EGCG. The fraction absorbed of EGCG after oral and intraduodenal administration of GTC were 13% and 22% of the dose, respectively. This result suggests a considerable degradation or elimination of EGCG in the gastrointestinal absorption after oral administration in rats.

• Korean Journal of Pharmacognosy
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• v.24 no.4
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• pp.319-321
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• 1993

A tannin compound has been isolated from the underground part of Rosa rugosa Thunb. and its structure has been established to be methyl gallate $3-O-{\beta}-D-(6'-O-galloyl)-glucopyranoside(1)$ on the basis of chemical and spectroscopic evidences. This compound was the first example in this plant.

• Parasites, Hosts and Diseases
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• v.58 no.5
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• pp.593-597
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• 2020

Kudoa septempunctata have been reported as a causative agent for acute transient gastrointestinal troubles after eating raw olive flounder (Paralichthys olivaceus). It raised public health concerns and quarantine control in several countries. Quantitative evaluation on viability of K. septempunctata is crucial to develop effective chemotherapeutics against it. A cytometry using fluorescent stains was employed to assess effect of three compounds on viability of K. septempunctata. Epigallocatechin gallate reduced markedly viability of K. septempunctata at 0.5 mM or more, and damaged K. septempunctata spores by producing cracks.

• International Journal of Oral Biology
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• v.45 no.4
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• pp.218-224
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• 2020

The antitumor effects of octyl gallate (OG) were investigated on FaDu human hypopharyngeal squamous carcinoma cells. At various concentrations, OG inhibited the proliferation of FaDu cells by suppressing cell cycle regulators and induced apoptosis by activating caspase 3 and its downstream poly (ADP-ribose) polymerase, thereby damaging DNA. Immunoblotting demonstrated that OG significantly suppressed the expression of integrin family proteins (integrin α4, αv, β3, β4), hindering cell adhesion. The reduced expression of integrins subsequently mediated the mitogen-activated protein kinase signaling pathway to stimulate the activation of extracellular signal-regulated kinases and c-jun N-terminal kinases, leading to apoptosis. Thus, OG demonstrated antitumor activity on hypopharyngeal squamous carcinoma cells by suppressing cell proliferation and inducing apoptosis.

• Journal of Food Hygiene and Safety
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• v.22 no.3
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• pp.223-230
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• 2007

We have previously reported that green tea catechins(GTC) displayed potent antithrombotic effect, which was due to the antiplatelet activity. In the present study, the antiplatelet activity of each green tea catechin components was compared in vitro. Galloylated catechins including (-)-epigallocatechin gallate (EGCG), (-)-gallocatechin gallate (GCG), (-)-epicatechin gallate (ECG) and (-)-catechin gallate (CG), significantly inhibited collagen $(5{\mu}g/mL)-induced$ rabbit platelet aggregation with $IC_{50}$ values of 79.8, 63.0, 168.2 and $67.3{\mu}M$, respectively. EGCC GCG and CG also significantly inhibited arachidonic acid (AA, $100{\mu}M$)-induced rabbit platelet aggregation with $IC_{50}$ values of 98.9, 200.0 and $174.3{\mu}M$, respectively. However catechins without gallate moiety showed little inhibitory effects against rabbit platelet aggregation induced by collagen or AA compared with galloylated catechins. These observations suggest that the presence of gallate moiety at C-3 position may be essential to the antiplatelet activity of catechins and the presence of B ring galloyl structure may also contribute to the antiplatelet activity of GTC. In line with the inhibition of collagen-induced platelet aggregation, EGCG caused concentration-dependent decreases of cytosolic calcium mobilization, AA liberation and serotonin secretion. In contrast, epigallocatechin (EGC), a structural analogue of EGCG lacking a galloyl group in the 3' position, although slightly inhibited collagen-stimulated cytosolic calcium mobilization, failed to affect other signal transductions as EGCG in activated platelets. Taken together, these observations suggest that the antiplatelet activity of EGCG may be due to inhibition of arachidonic acid liberation and inhibition of $Ca^{2+}$ mobilization and that the antiplatelet of EGCG is enhanced by the presence of a gallate moiety esterified at carbon 3 on the C ring.

• Journal of the Korean Wood Science and Technology
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• v.34 no.6
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• pp.61-71
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• 2006

This study was carried out to investigate chemotaxonomical correlation an d the chemical constituents of domestic Quercus sp. leaves. The leaves of Q. mongolica, Q. aliena, Q. serrata, Q. acutissima, Q. dentata and Q. variabilis were collected in the experimental forest of Kangwon National University. The combined extracts were successively fractionated with n -hexane, methylene chloride and ethyl acetate using a separation funnel. A portion of the ethyl acetate and $H_2O$ soluble materials of each species were chromatographed on a Sephadex LH-20 column using various aqueous MeOH and EtOH-hexane as washing solvents. Spectrometric analysis such as NMR and MS, including TLC, were performed to characterize the structures of the isolated compounds. Gallic acid, (+)-catechin, (-)-epicatechin, (+)-gallocatechin, kaempferol, astragalin, astragalin-6"-O-gallate, isoquercitrin, isoquercitrin-6"-O-gallate and myricetin were isolated from Q. mongolic a leaves. Gallic acid, kaempferol and quercetin were characterized from Q. acutissima leaves. Gallic acid, (+)-catechin, (-)-epicatechin, (+)-gallocatechin, (-)-epigallocatechin, kaempferol, quercetin, guajaverin and tamarixin were identified from Q. dentata leaves. Gallic acid, (+)-catechin, (-)-epicatechin, kaempferol, quercitrin, isoquercitrin and myricetin were purified from Q. serrata leaves. Gallic acid, (+)-catechin, astragalin, astragalin-6"-O-gallate and isoquercitrin were isolated from Q. variabilis leaves. Gallic acid was isolated from all the leaves and could be a taxonomic index on Quercus spp..

• Journal of the Korean Wood Science and Technology
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• v.45 no.3
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• pp.250-257
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• 2017

Eight hydrolyzable tannin compounds, such as gallic acid (1), methyl gallate (2), kurigalin (3), 1,2,3,6-tetra-O-galloyl-${\beta}$-D-(+)-glucose (4), 1,2,3,4,6-penta-O-galloyl-${\beta}$-D-(+)-glucose (5), 6-m-digalloyl-1,2,3,4,6-penta-O-galloyl-${\beta}$-D-(+)-glucose (6), isocorilagin (7), macabarterin (8), were isolated from the EtOAc and $H_2O$ soluble fractions of Katsura tree (Cercidiphyllum japonicum) leaves, wood and bark. Then antioxidative and anti-inflammatory activity were evaluated on the each isolated compound. The antioxidative test was DPPH radical scavenging activity and all of the isolated compounds indicated much higher antioxidative values compare to the controls, BHT and ${\alpha}$-tocopherol. In the anti-inflammatory test measuring nitric oxide (NO) inhibition activity, methyl gallate, 1,2,3,6-tetra-O-galloyl-${\beta}$-D-glucose and 1,2,3,4,6-penta-O-galloyl-${\beta}$-D-glucose inhibited NO production, and especially, methyl gallate showed high inhibition activity. However, the anti-inflammatory activity of the hydrolyzable tannins did not show positive effect. Based on the above results, the hydrolyzable tannins of katsura tree may be used as one of the natural biomass sources that can substitute with the synthetic antioxidant.

• Korean journal of food and cookery science
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• v.21 no.3 s.87
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• pp.346-353
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• 2005

CThis study used HPLC to analyze the contents of 7 kinds of catechins, 4 kinds of theaflavins, and 2 kinds of methylxanthines in the following 6 kinds of commercial Korean tea: 2 green, 2 black, 1 jasmine and loolong. The following ranges in the 13 tea components of the 6 samples by ethanol extract were evaluated in mg/g: (-)-epigallocatechin, 0(black tea and jasmine tea) to 14.19(green tea); (-)-catechin 0; (+)-epicatechin, 0.62(bran rice-green tea) to 2.91(black tea); (-)-epigallocatechin gallate, 4.59(black tea) to 43.96(jasmine tea); (-)-gallocatechin gallate, 0.58(black tea) to 5.80(jasmine tea); (-)-epicatechin gallate, 5.63(bran rice-ueen tea) to 48.06(jasmine tea): (-)-catechin gallate, 0.26(black tea): theaflavif 0 to 3.66(black tea): theaflavin-3-gallate, 0 to 6.94(black tea): theaflavin-3'-gallate, 0 to 4.01(black tea); theaflavin-3,3-digallte, 0 to 10.25(black tea); caffeine, 4.60(bran rice-peen tea) to 26.44(black tea); and theobromine, 0.10(bran rice-green tea) to 1.81(jasmine tea). The contents of all components were lower by water extract than by ethanol extract. Therefore, total catechin (100.55, 45.88 mg/g) and theobromine (1.81, 0.86 mg/g) contents in jasmine tea, and theaflavin content (24.88, 1.36 mg/g) in black tea by ethanol and water extract were the highest. Caffeine content was the highest in black tea(96.48 mg/g) for the ethanol extract, and in jasmine tea (12.38 mg/g) for the water extract.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.2
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• pp.93-99
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• 2008

Until now, (-)-epigallocatechin-3-gallate(EGCG) is known as the most powerful antioxidant among green tea catechins having many beneficial effects on human skin. Considering that the content of catechins is variable according to many conditions such as solvent, temperature and pressure, we prepared the heat-epimerized-EGCG-mixture (HE-EGCG-mix) containing high content of gallocatechin-3-gallate(GCG) by epimerization during autoclaving process and found out its optimal condition for maximizing conversion from EGCG to GCG. To investigate the effects of EGCG and HE-EGCG-mix on skin barrier function, we performed in vivo experiments with hairless mice. We found that HE-EGCG-mix has more potent stimulating activity than EGCG for the production of involucrin 7(INV7) and for recovery of barrier function in SKH-1 mice. Also, we found that GCG stimulates $PPAR-{\alpha}$ transactivation more effectively than EGCG in vitro by transient transfection assay for $PPAR-{\alpha}$ activation activity. These imply that HE-EGCG-mix consisting of high content of GCG should stimulate more efficiently recovery of skin barrier through PPAR-mediated-kerationocyte differentiation than EGCG. In conclusion, our study may provide a possibility that GCG, the C-2 epimer of EGCG, could be a potentially effective agent for development of new cosmetics or health foods for recovery of skin barrier.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.726-732
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• 2003

The crude extracts from Rhus javanica Linne showed comparatively strong antioxidative activity in test oils. Antioxidative components were isolated and identified by column chromatography, thin layer chromatography, UV, and NMR. These antioxidative components were added to several oils to compare antioxidative activity with several commercial antioxidants, such as BHA, BHT, and tocopherol. After the sixth column chromatography, one fraction (R-18-9-3-2-4-2) was separated from chloroform layer of Rhus javanica Linne. The R-18-9-3-2-4-2 fraction was identified as methyl gallate by $^1H-NMR$ and $^{13}C-NMR$ and confirmed with methyl gallate standard as authentic. The R18-9-3-2-4-2 fraction from chloroform layer of Rhus javanica Linne showed stronger activity than that of the ${\alpha}-,\;{\delta}-tocopherol$, BHT, and BHA at the same concentration.