Valavanidis Athanasios, Nisiotou Christala, Papageorgiou Yiannis, Kremli Ioulia, Satravelas Nikolaos, Zinieris Nikolaos, Zygalaki Helen
Department of Chemistry, University of Athens, University Campus Zografou, 15771 Athens, Greece.
J Agric Food Chem. 2004 Apr 21;52(8):2358-65. doi: 10.1021/jf030491h.
The antioxidant activity (IC(50)) of extra virgin olive oil (EVOO), commercial olive oil, and other vegetable oils (soybean, sunflower, and corn oil) was determined by UV-vis and by electron paramagnetic resonance (EPR) spectroscopy of the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Also, we studied the antioxidant activity of the methanol soluble phase (methanolic, MF) and the nonsoluble phase (lipidic, LF) of oils by the same methods. Similarly, we studied the effect of heating on the antioxidant activity at 160 and 190 degrees C. Also, the MF, containing the polyphenolic substances, was used for measurements of the radical scavenging capacity toward the most important oxygen free radicals, superoxide anion (O(2)()(-)) and hydroxyl (HO()) radicals. Results showed that soybean oil and EVOO had the highest antioxidant potential and thermal stability. In the case of soybean oil, the antioxidant capacity is the result of its high content of gamma- and delta-tocopherols (with the highest antioxidant capacity and thermostabilities), whereas in EVOO, the antioxidant potential is the result of the combination of specific antioxidant polyphenols, which are acting additionally as effective stabilizers of alpha-tocopherol. The high content of EVOO in tyrosol, hydrotyrosol, and oleuropein and other polyphenolics with radical scavenging abilities toward superoxide anion and hydroxyl radical suggests that olive oil possesses biological properties that could partially account for the observed beneficial health effects of the Mediterranean diet.
通过紫外可见光谱以及对稳定自由基2,2-二苯基-1-苦基肼（DPPH）的电子顺磁共振（EPR）光谱，测定了特级初榨橄榄油（EVOO）、市售橄榄油以及其他植物油（大豆油、向日葵油和玉米油）的抗氧化活性（IC(50)）。此外，我们还用相同方法研究了油类的甲醇可溶相（甲醇相，MF）和不可溶相（脂质相，LF）的抗氧化活性。同样，我们研究了在160℃和190℃下加热对抗氧化活性的影响。另外，含有多酚类物质的MF被用于测定对最重要的氧自由基超氧阴离子（O(2)()(-)）和羟基（HO()）自由基的自由基清除能力。结果表明，大豆油和EVOO具有最高的抗氧化潜力和热稳定性。就大豆油而言，其抗氧化能力是由于其富含γ-和δ-生育酚（具有最高的抗氧化能力和热稳定性），而在EVOO中，抗氧化潜力是特定抗氧化多酚共同作用的结果，这些多酚还可作为α-生育酚的有效稳定剂。EVOO中酪醇、羟基酪醇、橄榄苦苷以及其他对超氧阴离子和羟基自由基具有自由基清除能力的多酚类物质含量很高，这表明橄榄油具有一定生物学特性，这可能部分解释了地中海饮食所观察到的有益健康效果。
