| Project/Area Number |
10660132
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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 |
食品科学・栄養科学
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| Research Institution | University of Shizuoka |
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Principal Investigator |
NAKAYAMA Tsutomu University of Shizuoka, School of Food and Nutritional Sciences, Professor, 食品栄養科学部, 教授 (50150199)
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| Co-Investigator(Kenkyū-buntansha) |
KUMAZAWA Shigenori University of Shizuoka, School of Food and Nutritional Sciences, Assistant Professor, 食品栄養科学部, 助手 (10295561)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2000: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1998: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | hydrogen peroxide / HPLC / ECD / electrochemistry / analytical chemistry / SOD / catechins / EGCg / EGCg / electro chemistry / antioxidant / cigarette smoke |
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| Research Abstract |
We developed a new method to measure hydrogen peroxide(H_2O_2)by HPLC-ECD.By this method, we investigated effects of superoxide dismutase(SOD) on H_2O_2 formation in aqueous solutions of antioxidants such as ubiquinols, flavonols and catechins.
(1)The method to measure H_2O_2 by HPLC-ECD is convenient, selective and sensitive. It also enables us to measure H_2O_2 concentration in aqueous solutions of cigarette tar, coffee, and ascorbic acid.
(2)CoQ_0H_2 and myricetin are typical examples of a ubiquinol and a flavonol, respectively. Epigallocatechin gallate(EGCg), epigallocatechin(EGC), epicatechin gallate(ECg), and epicatechin(EC) are common catechins found in green tea. These compounds show antioxidant activity. But, they also show prooxidant activity under certain conditions owing to H_2O_2 formation. We measured H_2O_2 formed in aqueous solutions of these compounds by the HPLC-ECD method. SOD inhibited the H_2O_2 formation. The inhibition of H_2O_2 formation by SOD seems contradictory to the function of SOD, because H_2O_2 is a product of its enzyme reaction. This problem is solved by postulating a chain reaction in the formation of H_2O_2 with surperoxide as the chain carrier. We investigated cytotoxicity of myricetin, EGCg and EGC by a colony formation assay with Chinese hamster V79 cells. Inhibitory effects of catalase and SOD indicate that the cytotoxic effects were attributable to H_2O_2 formation where superoxide was involved.
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