2002 Fiscal Year Final Research Report Summary
Antioxidant Mechanism Studies for Food Phenol Based on the Radical Reaction Products with Food Components
| Project/Area Number |
12660116
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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 | The University of Tokushima |
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Principal Investigator |
MASUDA Toshiya The University of Tokushima, Faculty of Integrated Arts and sciences, Associate Professor, 総合科学部, 助教授 (10219339)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEDA Yoshio The University of Tokushima, Faculty of Integrated Arts and sciences, Professor, 総合科学部, 教授 (70025716)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Antioxidant Mechanism / Food phenol / Curcumin / Carnosic Acid / turmeric / Sage / Radical Termination Reaction |
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| Research Abstract |
The antioxidation process of the chain-breaking antioxidant is divided into the following two stages : 1) Radical Trapping Stage (S-OO + AH →← SOOH + A) 2) Radical Termination Stage (A → non-radical materials) The second is irreversible and must produce stable radical termination compounds. The chemical structure of such a termination compound would afford important information in order to elucidate the antioxidant mechanism of the chain breaking antioxidant. Curcumin is a famous antioxidatively active food phenol from turmeric. By this research for the antioxidant mechanism based on the chemical structures of the radical termination products, curcumin is revealed to react with a peroxyl radical to afford stable 3-ringed compounds. When curcumin is in a higher concentration, it affords dimers as terminated compounds. Carnosic acid is an abietane diterpene found in the popular Labiatae herbs, sage and rosemary. Carnosic acid has the most powerful antioxidant potency among related diterpenes. The 11-phenolic group of carnosic acid first undergoes hydrogen donation to a radical species and the radical termination takes place next with a second lipid peroxyl radical at the ortho and parapositions. When the coupling proceeds at the 12-position (ortho-position), it affords a carnosic quinone through several steps. When the coupling proceeds at the 14-position (para-position), it affords a hydroxylparaquinone derivative. Generally, antioxidant loses the activity after its work. The orthoquinone derivative of carnosic acid has no antioxidant activity ; however, we found that its solution became to show potent antioxidant activity. The recovery mechanism of the antioxidant activity from the quinone was clarified to be by a self-redox reaction of the quinone, therefore, procuded carnosic acid contributes the strong antioxidant activity of the quinone solution.
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