Nutritional and Biochemical Study on the Role of Nitric Oxide in the Physiological Effects of Tea Extract
| Project/Area Number |
07680033
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
家政学
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| Research Institution | OSAKA CITY UNIVERSITY |
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Principal Investigator |
YUASA Isao Osaka City University, Faculty of Human Life Science, Professor, 生活科学部, 教授 (50094488)
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| Co-Investigator(Kenkyū-buntansha) |
OHTANI Kimiko Kyoto Prefecture University, Faculty of Living Science, Associate Professor, 生活科学部, 助教授 (60148632)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1996: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1995: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Tea polyphenols / Nitric oxide / Polamines / Oncogenes / Tyrosine phosphorylation / Antitumor effect / Hepatoprotective effect / Nutritional Biochemistry / 肝障害保護作用 |
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| Research Abstract |
We have shown that epigallocatechin has the most antitumor effect in tea polyphenols and the effect is mediated by the inhibition of polyamine metabolism. Here, we studied the effects of the tea polyphenol on oncogenes and signal transduction in tumor cells and found that the polyphenol affects the expression of the oncogene c-fos. We also studied the effect of the polyphenol on tyrosine phosphorylation and found that the polyphenol enhanced the phosphorylation of the tyrosine residues of 42 and 45KDa proteins in a dose- and time-dependent manner. The functions of these proteins are under investigation. These findings on the effect of tea polyphenol on the expression of oncogene and tyrosine phosphorylation is new and important to understand the mechanism of anticarcinogenic effect. Furthermore, we studied the effect of tea polyphenols upon nitric oxide production. Nitric oxide plays important roles in regulating immune function, blood vessel dilation, brain and peripheral nervous system and interactions of the various other cells and tissue. Within the cardiovasucular system, it mediates vascular smooth muscle relaxation, inhibits both leukocyte adhesion and platelet aggregation, and is the biochemical endproduct of endothelium-derived relaxing factor. In this study, we examined the effects of polyphenols on nitric oxide production in Ehrlich ascites tumor cells, and found that polyphenols enhanced the production of nitric oxide. These results suggested that nitric oxide formed by tea polyphenols is involved inome pharmacological functions of tea. We also examined the effect of tea extract and tea polyphenols against drug-induced hepatotoxicity in primary cultured rat hepatocytes. The injury of hepatocytes was improved by the addition of sunphenon and tea polyphenols, especially epigallocatechin gallate and epicatechin gallate, and this was mediated by the maintenance of protein thiols.
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Report
(3 results)
Research Products
(3 results)
