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Nutritional and Biochemical Study on the Role of Nitric Oxide in the Physiological Effects of Tea Extract

Research Project

Project/Area Number 07680033
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 家政学
Research InstitutionOSAKA CITY UNIVERSITY

Principal Investigator

YUASA Isao  Osaka City University, Faculty of Human Life Science, Professor, 生活科学部, 教授 (50094488)

Co-Investigator(Kenkyū-buntansha) OHTANI Kimiko  Kyoto Prefecture University, Faculty of Living Science, Associate Professor, 生活科学部, 助教授 (60148632)
Project Period (FY) 1995 – 1996
Project Status Completed (Fiscal Year 1996)
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)
KeywordsTea polyphenols / Nitric oxide / Polamines / Oncogenes / Tyrosine phosphorylation / Antitumor effect / Hepatoprotective effect / Nutritional Biochemistry / 肝障害保護作用
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.

Report

(3 results)
  • 1996 Annual Research Report   Final Research Report Summary
  • 1995 Annual Research Report
  • Research Products

    (3 results)

All Other

All Publications (3 results)

  • [Publications] M.Wadatani et al.: "Prevention of ornithine decarboxylase induction in Ehrlich ascite tumor cells by tea polyphenols" The Cancer Journal. 9・3. 161-167 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] M.Wadatani, K.Ohtani, K.Kageyama, Y.Yano, T.Hasuma, S.Otani, S.Sakanaka, M.Kim and I.Matsui-Yuasa: "Prevention of ornithine decarboxylase induction in Ehrlich ascites tumor cells by tea polyphenols" The Cancer Journal. Vol.9 No.3. 161-167 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1996 Final Research Report Summary
  • [Publications] M. Wadatani et al.: "Prevention of ornithine decarboxylase induction in Ehrlich ascite tumor cells by tea polyphenols" The Cancer Journal. 9・3. 161-167 (1996)

    • Related Report
      1996 Annual Research Report

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Published: 1995-04-01   Modified: 2016-04-21  

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