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Effect of Reaction Media on the Scavenging Reaction of Water-Solubilized 2,2-Diphenyl-1-picrylhydrazy Radical by Ascorbic Acid
https://repo.qst.go.jp/records/82316
https://repo.qst.go.jp/records/823160fb9569c-4c9f-47c6-910c-ac9e9f0753b3
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2020-12-08 | |||||
| タイトル | ||||||
| タイトル | Effect of Reaction Media on the Scavenging Reaction of Water-Solubilized 2,2-Diphenyl-1-picrylhydrazy Radical by Ascorbic Acid | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
Nakanishi, Ikuo
× Nakanishi, Ikuo× Shoji, Yoshimi× Ohkubo, Kei× Ozawa, Toshihiko× Ken-ichiro, Matsumoto× Fukuzumi, Shunichi× Ikuo, Nakanishi× Yoshimi, Shoji× Kei, Ohkubo× Toshihiko, Ozawa× Kenichiro, Matsumoto |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Background: The radical-scavenging reaction of antioxidants is known to be significantly affected by pH, solvents, and metal ions. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical has been used to evaluate the radical-scavenging activity of antioxidants as a reactivity model of reactive oxygen species. However, the insolubility of the DPPH radical in water has precluded its use in aqueous media. Recently, we have succeeded in solubilizing the DPPH radical in water using β-cyclodextrin (β-CD). This enables us to evaluate the scavenging activity of the DPPH radical by antioxidants in aqueous media. We report herein the effect of reaction media on the scavenging reaction of the DPPH radical by ascorbic acid, a representative water-soluble antioxidant. Methods: 25 mL of boiling water (Milli-Q) was added to the mixture containing the DPPH radical (0.15 mmol) and β-CD (0.70 mmol), and the suspension was cooled to room temperature. The filtration of the suspension by a membrane filter (pore size: 0.22 µm) gave a deep violet solution of the DPPH radical. The rates of the scavenging reaction of the DPPH radical were determined by monitoring the absorbance change due to the DPPH radical using a stopped-flow technique on a UNISOKU RSP-1000-02NM spectrophotometer. Results: The second-order rate constant (k) of the reaction between ascorbic acid and the β-CD-solubilized DPPH radical was determined to be 5.4 × 103 M–1 s–1 in phosphate buffer (0.05 M, pH 7.0) at 25 °C. The k value increased with increasing the pH value. Furthermore, magnesium perchlorate significantly accelerated this reaction. On the other hand, when water was replaced by deuterium oxide to prepare the phosphate buffer (0.05 M, pD 7.0), the k value significantly decreased to be 1.5 × 103 M–1 s–1. Conclusion: The scavenging reaction of the DPPH radical by ascorbic acid is significantly affected by reaction media. |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | 20th Biennial Meeting of SFRR International (SFRR-I 2021) | |||||
| 発表年月日 | ||||||
| 日付 | 2021-03-17 | |||||
| 日付タイプ | Issued | |||||
