Kinetic Activity Evaluation of Antioxidants in Aqueous Solutions Using a Water-Solubilized Organic Radical
| Project/Area Number |
18K06620
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 47020:Pharmaceutical analytical chemistry and physicochemistry-related
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| Research Institution | National Institutes for Quantum Science and Technology |
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Principal Investigator |
Nakanishi Ikuo 国立研究開発法人量子科学技術研究開発機構, 量子生命科学研究所, 上席研究員 (70356137)
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| Project Period (FY) |
2018-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2020: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | 抗酸化物質 / ラジカル / 反応速度 / 反応機構 / 活性酸素種 / 水素移動 / 電子移動 / 物理化学 / pH / 速度論 |
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| Outline of Final Research Achievements |
The kinetic radical-scavenging activity of antioxidants in buffer solutions was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical solubilized by beta-cyclodextrin in water. The second-order rate constants for the scavenging reaction of the water-solubilized DPPH radical by Trolox, a water-soluble analog of vitamin E, (+)-catechin, ascorbic acid, and caffeic acid, increased with increasing the pH of the phosphate buffer solutions. The acceleration of the reaction between these antioxidants and the water-solubilized DPPH radical was also observed by the addition of magnesium ion, suggesting that an electron transfer may be involved as the rate-determining step. A large kinetic isotope effect observed in the scavenging reaction of the water-solubilized DPPH radical by Trolox indicates that the quantum tunneling plays a role in the hydrogen-transfer reaction from Trolox to the water-solubilized DPPH radical in the phosphate buffer solution.
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| Academic Significance and Societal Importance of the Research Achievements |
水溶化したDPPHラジカルを用いることにより、これまで不明な点が多く残されていた水溶液中における抗酸化物質のラジカル消去活性が明らかとなった。これまで65年以上にわたり蓄積されてきた有機溶媒中におけるDPPHラジカル消去活性のデータと本研究で得られた知見を比較することで、抗酸化物質のラジカル消去活性に対する反応環境の影響を系統的に明らかにすることができ、本研究の学術的意義は極めて大きい。また、細胞実験や動物実験で得られた抗酸化活性のデータとの比較により、生活習慣病や老化の予防に応用できる高効率な抗酸化物質の開発につながる可能性があり、本研究で得られた成果の社会的な波及効果は計り知れない。
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Report
(6 results)
Research Products
(178 results)
