Lowest Price of the Year
Microwavable Shoulder Herbal Heat Wrap
$19.99
The 4th International symposium on Green Tea, Sept. 3, 1997, Seoul, Korea
1. The effect of catechin on Alzheimer's disease
2. Effect of green tea on peroxidative damage and expression of genes related with antioxidative defense system in rat liver exposed to microwaves
3. Inhibition of tobacco carcinogen-induced lung tumorigenesis in A/J mice by green tea and its major polyphenol as antioxidants
4. Protective effects of green tea polyphenols on the ultraviolet-induced dermal extracellular damage
5. Protection against Cancer risk by Green Tea and Antibacterial activity of Tea Catechin against Helicobactor pylori
6. Studies on Analysis and Synthetic Extraction of Pharmaceutical Components in green tea on Curing Diabetes.
7. Biochemical studies on tumor non-promoting effect of green tea extract in DMH-treated rats.
8. Utilization of Tea Extracts and The Prospect of Catechins as Anticancer Agents
9. Protective effects of green tea against oxidative damage in rats treated with acute ethanol.
Title
Effect of green tea on peroxidative damage and expression of genes related with antioxidative defense system in rat liver exposed to microwaves
Speaker
Soon-Jae Rhee
Dept. of Food Science and Nutrition, Catholic University of Taegu-Hyosung, Korea
Abstract
The damage of tissues on account of the exposure to the microwaves and defense effect of the damage by the administration of green tea were observed on rats.
The rats were divided into two groups : control group and green tea (GT) group which was administrated the distilled water and MW green tea extracts for 14 days before the irradiation of microwave. The rats were irradiated with microwave at frequency of 2.45GHz for 15 min, and then the change pattern of MFO system, antioxidative defense system, peroxidative damage of tissues and gene expression in the damaged tissues were investigated for 16 days to compared with the normal group which was not irradiated and administrated the green tea. The activity of cytochrome P450 in the liver was gradually increased to the level of normal group at 16 days after irradiation with microwaves, and that of GT group was similar to the normal group. The activity of NADPH-cytochrome P450 reduced in GT group became less than that of MW group at 4 and 6 days after the irradiation.
The activity of superoxidase dismutase (SOD) in both group of MW and GT was similar to that of the normal group even though the activity in both groups was apt to be increased. The activity of glutathione peroxidase (GSH-px) in MW group was lower than the normal group at 4 and 6 days after the irradiation, but increased to the level of normal group at 16 days. The activity of GT group was the same levels as the normal group, but was higher than the normal group from 8 days after the irradiation with microwave. The activity of glutathione S-transferase (GST) in MW group was generally decreased at first, but reached to the level of normal group after the irradiation. The activity of GST in GT group was similar to the normal group during the irradiation. The content of thiobarbituric acid reactive substances (TBARS) in liver of MW group was increased to 1.6, 1.5, 1.7 and 1.3 fold of the normal group at 2, 4, 6 and 8 days after the irradiation respectively, but recovered to the level of normal group at 16 days. The content of TBARS in liver of GT group was increased to 1.3 fold of the normal group at 2 and 4 days but recovered to the level of normal group at 8 days after the irradiation. The level of SOD gene expression in MW group was lower than the normal group within 6 days, but that of GT group was higher than MW group. The GSH-Px gene was expressed a little bit lower than the normal group, but that of GT group was expressed to higher level than MW group from 4 days after the irradiation. It was suggested that the damage of liver tissues were alleviated and rapidly recovered to the normal level by the contribution to the normalization of imbalances in antioxidative system with the administration of green tea extract.
Title
Inhibitions of tobacco carcinogen-induced lung tumorigenesis in A/J mice by green tea and its major polyphenol as antioxidants
- Speaker
- Fung-Lung Chung
- American Health foundation
- Fung-Lung Chung
Abstract
In this study we examined the effects of green tea, its major components (-)-epigallocatechin gallate (EGCG), and caffeine on the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induced lung tumorigenesis in A/J mice. We also studied the effects of green tea and EGCG on O6-methylguanine (O6-mG) and 8-hydroxydeoxyguanosine (8-OH-dG) formation in lungs caused by NNK treatment. Mice were given 2% tea infusion, 560ppm EGCG, or 1120ppm caffeine solution as drinking water 13 weeks. During this time, NNK (11.65mg/kg b.w.) was administered by gavage 3 times weekly for 10 weeks from weeks 3 to 12. The bioassay was terminated 6 weeks after the last NNK treatment. Mice treated with NNK developed 22.5 lung adenomas per mouse, whereas NNK treated mice that drank green tea or EGCG as drinking water developed only 12.2 and 16.1 tumors per mouse. Mice that drank green tea or caffeine solution showed lowered body weight gains, although little difference in water and diet consumption was noted in these groups. While green tea and EGCG exerted little effect on the formation of O6-mG, both treatments suppressed the increase of 8-OH-dG levels in mouse lung DNA. The inhibition of 8-OH-dG formation in lung DNA by green tea and EGCG is consistent with their ability to inhibit lung tumorigenesis by NNK. Because 8-OH-dG is a DNA lesion caused by oxidative damage, these results suggest that the mechanism of inhibition by green tea and EGCG in NNK-induced lung tumorigenesis is due at least partly to their antioxidant properties.
Protective effects of green tea polyphenol on the ultraviolet-induced dermal extracellular damage
- Speaker
- Kyu-Hwan Yang
- Dept. of biological Science, Korea Advanced Institute of Science and Technology
- Kyu-Hwan Yang
Abstract
UV-irradiation has been known to lead skin photoaging including skin cancer and the wrinkle formation. The reactive oxygen intermediates produced in the UV-irradiated skin induced various matrix metalloproteinases (MMPs) such as collagenase, stromelysin and gelatinase, etc. which degrade extracellular matrix. UV irradiation also reported to upregulate the transcription factors, NF-ナB and AP-1, which are known to be stimulators of MMP genes. Meanwhile, it has been known that green tea and its components possess significant chemopreventive effects against chemical carcinogens- and photo-caused skin tumor formation. In this study, protective effects of green tea polyphenols (GTP) on the UV-induced skin damage (photoaging) were studied. DPPH (1,1-diphenyl-2-picryl-hydrazyl) was used for the free radical scavenging experiments. UV-induced erythma was measured by the colorimetric evaluation of Chromameter, and TBA method was used for the lipid peroxidation test. The inhibition of collagenase mRNA and protein synthesis was assayed by the Northern blot assay and ELISA NF-ナB and AP-1 binding activity were measured using electrophoretic mobility shift assay.
Among several GTP tested, (-)-epigallocatechin 3-O-gallate (EGCG) showed the maximum protective effects against UV-induced skin damage. The 50% scavenging dose (SC50) of EGCG was 3.3 レg/ml, while that of vitamin E was 16.5 レg/ml. The erythma relative index of the control and the EGCG treated group was 268‐88 and 159‐53, respectively. The lipid peroxidation was significantly reduced in the EGCG treated group. EGCG decreased collagenase both in protein and mRNA level. The nuclear transcription factor, NF-ナB and AP-1 binding activity was also inhibited by the EGCG treatment. These results indicated that EGCG might protect against UV-induced skin damage through the regulation of cellular redox state.
Protection against cancer risk by green tea and antibacterial activity of tea catechin against Helicobactor pylori
- Speaker
- Itaro Oguni
- Dept. of Food and Nutrition, University of Shizuoka, Japan
- Itaro Oguni
Abstract
Cancer mortality statistics on Japanese people indicated that the death rate from cancer of both males and females in Shizuoka prefecture located in the central Japan is much lower than the average of Japanese people. We further investigated this phenomenon epidemiologically and experimentally. Also recently, Helicobactor pylori (H. pylori) was strongly suggested to play a role in gastric carcinogenesis. We investigated the effect of tea catechin against H. pylori. The results were as follows.
(1) In the Midwest areas of Shizuoka pref. where green tea is the staple product, the standardized mortality ratios (SMRs) for cancer of all sites and stomach cancer were much lower than the average ratio of Japanese people in both sexes.
(2) The survey analysis of green tea intake indicated that the inhabitants in the areas with low SMR due to stomach cancer seemed to have been much more habitual in drinking green tea compared with those of the areas with high SMR.
(3) Oral administration of crude extracts of green tea inhibited the growth of mouse sarcoma 180 inoculated into mice.
(4) Oral administration of crude extracts of green tea inhibited the incidences of the carcinoma in both esophagus and forestomach in mice induced by in vitro formation of nitrososarcosine from its precursors, sarcosine (a secondary amine) and sodium nitrite.
(5) Tea catechin had an antibacterial activity against H. pylori.
These results strongly suggested that green tea played a role in protecting against cancer risk.
Studies on analysis and synthetic extraction of pharmaceutical components in green tea on curing diabetes
- Speaker
- Wang Dongfeng
- Department of tea science, Anhui agricultural university, China
- Wang Dongfeng
Abstract
There is very popular folk remedy of using green tea to cure diabetes in China and Japan. According to the analysis of the content of main pharmaceutical components in green tea, it was found that the lower tea grade was, the less the content of polyphenols, catechin and caffeine contained. However the content of crude tea polysaccharide (CTPS) was on the contrary. CTPS had effect on reducing blood sugar and enhancing immunity of the mice. CTPS was composed of polysaccharide, protein, ash and other components etc. Polysaccharide was made up of five monosaccharides, its molecular weight was about 107000. Protein in CTPS was about composed of 13 amino acids. About 1.6% caffeine, 4.0% tea polyphenols (TP) and 2.3% CTPS could be extracted from green tea by a new synthetic extraction method studied by authors. Green tea resource is very in China and other countries. It is very valuable to exploit CTPS in coarse tea and to be used in food and medicine.
Biochemical studies on tumor non-promoting effect of green tea extract in DMH-treated rats
- Speaker
- Hyun-Suh Park
- Dept. Food & Nutrition, Kyunghee University, Korea
- Hyun-Suh Park
Abstract
This study was designed to observe the effect of green tea on colon carcinogenesis in 1,2-dimethylhydrazine (DMH) treated rats. Males Sprague Dawley rats, at 7 weeks old, were divided into 4 groups, i.e. control group : distilled water supplied as drinking water for 20 weeks ; green tea group (GT) : green tea extract (2.5% w/v water) supplied for experimental period ; third group (GT-I) : green tea extract supplied for the first part of 10 weeks and then water for 10 weeks, and forth group (GT-II) : water for the first part of 10 weeks and then green tea extract supplied for 10 weeks. All rats were fed the same experimental diet and injected i.m. with DMH (180mg/kg).
Tumor incidence was lower in GT group (39%) than control (47%). Crypt length and proliferative zone in colonic mucosa were significantly decreased by green tea when supplied throughout the experimental period. However, there was no significant effect by green tea when supplied for 10 weeks (GT-I and GT-II). The levels of PGE2 and TXA2 in colonic mucosa were lower in GT group than control (p<0.0001). Content of C20:4 and the preformed level of PGE2 and TXA2 in tumor tissues were higher than normal mucosa. Green tea significantly increased fecal excretion of total bile acid but not secondary bile acid.
These results suggest that green tea could have preventive effect against colon cancer when consumed daily by influencing on antioxidant effect and the metabolism of arachidonic acid.
Title
Utilization of tea extracts and the prospect of catechins as anticancer agents
- Speaker
- Du Qizhen
- Tea Research Institute, Chinese Academy of Agricultural Sciences, China)
- Du Qizhen
Abstract
In recent ten years, much attention has been paid to the research and development of tea extracts, and tea extracts has been extensively being used in daily chemical products, food, health care, medical products and other products. This paper summarizes 49 patent uses of tea extracts and some nonpatent uses such as using tea polyphenols and tea pigments as food antioxidants and therapeutic medicines of heart and brain vessel diseases. The 49 patents include 15 in daily chemical products, 21 in health care and medical products, 8 in foods and 5 in other products.
The research results of recent ten years showed catechins, especially EGCG, have prevention effects on cancers and can also repress the growth of cancer cells. Based on the results we expect that catechins can be used as cancer prevention agents and medicines for cancer therapy in the near future.
Protective effects of green tea against oxidative damage in rats treated with acute ethanol.
- Speaker
- Yong-Ku Han
- Pacific R&D Center Institute of Skin Biology Safety, Efficacy, Microbiology team, Korea
- Yong-Ku Han
Abstract
Ethanol has been known to produce membrane damage through increased lipid peroxidation leading to impairment of various tissues. Especially, growing evidence suggests that free radical mechanisms have been contributed to ethanol-induced liver injury. An increased generation oxygen species such as superoxide (O2-) and H2O2 has been observed in liver microsomes through the intervention of the ethanol-inducible cytochrome P450.
In this study, to investigate the effect of green tea on ethanol metabolism and ethanol-induced oxidative stress, we estimated ethanol blood concentration and antioxidant system such as superoxide dismutase (SOD) activity and glutathione content in rats. Rats were fed on commercial food with 1%(v/v) green tea solution as drinking liquid for one month and ethanol administration as a 50% solution in I.P. injection.
Total superoxide dismutase activity, vitamin E and glutathione content in ethanol-treated rats were in general reduced in comparison to that of their matched controls. Oral application of green tea resulted in significant reduction against ethanol-induced oxidative damage, and ethanol blood concentration.
Some of the cellular damages observed following ethanol challenges could be attributed to the reduced level of these antioxidative systems. Our study suggests that green tea may be useful against oxidative damage caused by ethanol.
Our Deluxe Sampler Package 2 each so you can share with a friend |
||
| Premium Green Tea | Genmaicha Tea | Hojicha Tea |
 |
 |
 |
Shopping Cart
Product Search
Contact Us
