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An Efficient Method for Assessing Hydroxyl Radical Scavenging Activity of Hydrophilic Antioxidants
https://repo.qst.go.jp/records/70619
https://repo.qst.go.jp/records/7061915b250cf-851b-48d6-8a28-5f5f0dfbf68f
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2011-11-15 | |||||
| タイトル | ||||||
| タイトル | An Efficient Method for Assessing Hydroxyl Radical Scavenging Activity of Hydrophilic Antioxidants | |||||
| 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 |
Matsumoto, Kenichiro
× Matsumoto, Kenichiro× Nakanishi, Ikuo× 松本 謙一郎× 中西 郁夫 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Hydroxyl radical (•OH) is one of most important player in oxidative stress; because, •OH is the most reactive species of reactive oxygen species (ROS). The •OH can be measured using electron paramagnetic resonance (EPR) spin-trapping method; however, spin-trapping •OH in in vivo system is still quite difficult because of interruption by biological reductants. Generally, •OH-scavenging-effect of anti-oxidants have been estimated by a method adding the anti-oxidant and a spin-trapping agent to an •OH generation system. Fenton reaction system or irradiating UV to hydrogen peroxide (H2O2) has been often used for generating •OH. Using Fenton reaction system for estimating •OH-scavenging-effect of an anti-oxidant, iron-chelating effect of the anti-oxidant and/or reaction of H2O2 with the anti-oxidant must be considered to estimate the •OH-scavenging-effect correctly. For using UV+H2O2 reaction system, reaction of H2O2 with the anti-oxidant and absorption of UV by the anti-oxidant must be considered for correct estimation of the •OH-scavenging-effect. To remove such complexity, X-ray irradiation to water was used to generate •OH. In this simple system, estimation of the •OH-scavenging-effect of an anti-oxidant can be much simpler. In addition, reduction of spin adduct with the anti-oxidant in this reaction system must be considered to do correct estimation. In this presentation, an efficient method for estimating •OH-scavenging-effect of an anti-oxidant is proposed. A reaction mixture containing 15 mM of a spin-trapping agent (DMPO) was prepared using 100 mM phosphate buffer (pH7, containing 0.05 mM DTPA). The reaction mixture was irradiated by 32 Gy X-ray. Time course of the amount of the •OH-spin-adduct (DMPO-OH) for 10 min was measured using X-band EPR spectrometer immediately after irradiation. The reduction rate kcont and the concentration of DMPO-OH at the end of the X-ray irradiation C0cont was calculated from the experimental reduction curve of DMPO-OH. With neglecting reduction of DMPO-OH during X-ray irradiation, then, net generation of DMPO-OH during the X-ray irradiation C0net was simulated. Next, a reaction mixture containing 15 mM of a DMPO and an arbitrary concentration of an anti-oxidant was prepared and irradiated by 32 Gy X-ray. Similarly, the reduction rate kexp and the concentration of DMPO-OH at the end of the X-ray irradiation C0exp were calculated from the experimental reduction curve. The net concentration of DMPO-OH at the end of the X-ray irradiation C0net in the reaction mixture containing the anti-oxidant was calculated with neglecting reduction of DMPO-OH during X-ray irradiation, and compared to experimental amount C0exp. The percentage difference of C0exp compare to the C0net was estimated as cancelation of •OH. When anti-oxidant 1 was added to the reaction mixture, amount of X-ray induced DMPO-OH in the reaction mixture was decreased depending on the dose of the anti-oxidant 1. The reduction rate of DMPO-OH in the reaction mixture containing anti-oxidant 1 was similar as the control; therefore, the reducing DMPO-OH amount by adding anti-oxidant 1 was mainly due to cancelation of •OH by the anti-oxidant 1. Anti-oxidant 2 also showed the reducing DMPO-OH amount, when the anti-oxidant 2 was added to reaction mixture. Anti-oxidant 2, however, showed a rapid reduction of DMPO-OH. Scavenging •OH by anti-oxidant 2 can not be estimated directly from the comparison of experimental value, however, comparing C0net make the estimation possible. Anti-oxidant 2 was a strong reductant which can be reduce relatively stable nitroxyl radical (DMPO-OH in this case). Using the method in this experiment, anti-oxidative property can be estimated using both scavenging •OH and reducing DMPO-OH. |
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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 | International Workshop "Advanced ESR Studies for New Frontiers in Biofunctional Spin Science and Technology" | |||||
| 発表年月日 | ||||||
| 日付 | 2011-11-14 | |||||
| 日付タイプ | Issued | |||||
