Development of flow-injection ESR system for evaluation of antioxidant activity of hydrophobic and hydrophilic compounds involved in vegetables

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K07817
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Food science
• Research Institution: Kyoto Institute of Technology
• Principal Investigator: Tajima Kunihiko 京都工芸繊維大学, 分子化学系, 教授 (50163457)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 抗酸化活性 / 脂溶性物質 / アルコキシルラジカル / スーパーオキシドラジカル / 電子スピン共鳴

Outline of Final Research Achievements

A new lipophilic spin-trapping flow-injection electron spin resonance (LFI-ESR) system was developed for quantitative detection of DMPO spin-adduct of alkoxyl radical (RO・), which was produced by thermal decomposition of an azo-initiator (AIBN) in ethyl acetate at 70 °C. The 50% inhibition dose (ID50) of tocopherol derivatives, and unsaturated fatty acids, were determined by monitoring the ESR signal intensity of the DMPO spin-adducts of RO・ radical (DMPO/OR). On the basis of the observed ID50 values, the lipophilic alkoxyl radical eliminating capacities (L-AREC) of these lipophilic antioxidants were determined using TRX as a standard. The L-AREC values estimated by LFI-ESR method are concluded to be a practical and reliable indicator that reflect the inhibiting abilities of lipophilic antioxidants towards the radical chain reaction involved in the autoxidation processes of unsaturated fatty acids.

Free Research Field

分子構造化学

Academic Significance and Societal Importance of the Research Achievements

近年、青果物に含まれる種々の機能性物質が我々の健康維持と促進に大きな役割を果たすことが広く認識され、有用物質を高濃度で含有する青果物の獲得に向けた品種改良と栽培技術の改良が多方面で研究されてきた。青果物の抗酸化活性はそれらの品質に直結する重要な機能性のひとつであるため、その活性を数値化する方法論に関する研究が継続されてきた。しかし、脂溶性物質の抗酸化活性を簡便かつ精度良く数値化する分析法の開発は立ち後れていた。本研究では、アルコキシルラジカル（RO・）の還元反応の効率を基準物質（TRX）濃度換算値として数値化する計測技術、装置開発および解析技術を確立することができた。