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Effect of Magnesium Ion on the Radical-Scavenging Reaction of Pterostilbene and the Mechanism
https://repo.qst.go.jp/records/84368
https://repo.qst.go.jp/records/8436817fae05d-21a8-4433-82b8-1358aa05570d
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2021-12-09 | |||||
| タイトル | ||||||
| タイトル | Effect of Magnesium Ion on the Radical-Scavenging Reaction of Pterostilbene and the Mechanism | |||||
| 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 |
Ikuo, Nakanishi
× Ikuo, Nakanishi× Yoshimi, Shoji× Kei, Ohkubo× Megumi, Ueno× Matsumoto, Ken-ichiro× Kiyoshi, Fukuhara× Hiroki, Hamada× Ikuo, Nakanishi× Yoshimi, Shoji× Kei, Ohkubo× Megumi, Ueno× Kenichiro, Matsumoto |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Resveratrol (1), 3,5,4'-trihydroxy-trans-stilbene, found in grapes is one of the representative antioxidants that shows a plethora of remarkable biological properties. On the other hand, pterostilbene (2), a methylated analog of 1, has attracted much attention due to its enhanced bioavailability as compared to that of 1. However, little is known about the radical-scavenging mechanism of 2. There are two mechanisms in the radical-scavenging reaction of phenolic antioxidants: a one-step hydrogen-atom transfer from the phenolic OH group; and an electron transfer followed by proton transfer. Redox inactive metal ions, such as magnesium ion (Mg2+), are a powerful tool to distinguish between these two mechanisms, because electron-transfer reactions are known to be accelerated by their presence. In fact, a significant acceleration in the radical-scavenging reaction of 1 was observed in the presence of Mg2+ in acetonitrile (MeCN), suggesting that the reaction may proceed via the electron-transfer mechanism (Chem. Lett. 2007, 36, 1276). We report herein the effect of Mg2+ on the scavenging reaction of galvinoxyl radical (GO) by 2 in MeCN. GO has been frequently used as a reactivity model of reactive oxygen radicals to estimate the activity of antioxidants. Upon mixing of 2 with GO on a UNISOKU RSP-1000-02NM stopped-flow spectrophotometer in MeCN at 298 K, a gradual decrease in the absorption band at 428 nm due to GO was observed, indicating that 2 efficiently scavenged GO. From the time course change in the absorbance at 428 nm, the second-order rate constant (k) for the reaction between 2and GO was determined to be 1.3 × 10 M−1 s−1, which is about 3-fold larger than that of 1 (4.1 M−1 s−1). When Mg(ClO4)2 (0.1−0.3 M) was added to the 2−GO system, no effect of Mg2+ on the k values was observed. Thus, the GO-scavenging reaction by 2 may proceed via the one-step hydrogen-atom transfer rather than the electron transfer followed by proton transfer. |
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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 | PACIFICHEM 2021 | |||||
| 発表年月日 | ||||||
| 日付 | 2021-12-19 | |||||
| 日付タイプ | Issued | |||||
