Juliano Claudia, Cossu Massimo, Alamanni Maria Cristina, Piu Luisella
Dipartimento di Scienze del Farmaco, Via Muroni 23/A, University of Sassari, Sassari, Italy.
Int J Pharm. 2005 Aug 11;299(1-2):146-54. doi: 10.1016/j.ijpharm.2005.05.018.
Gamma-oryzanol, a phytosteryl ferulate mixture extracted from rice bran oil, has a wide spectrum of biological activities; in particular, it has antioxidant properties and is often used in cosmetic formulations as a sunscreen. The first objective of the present investigation was to elucidate the molecular mechanism(s) of the antioxidant activity of gamma-oryzanol by utilising different in vitro model systems, such as scavenging of stable DPPH radical, OH and O2- radicals scavenging, and azocompound AMVN-initiated lipid peroxidation. The effect of gamma-oryzanol on the oxidative stability of vegetable oils of pharmaceutical and cosmetic interest was then evaluated in a oxidation accelerate test and compared with the effect of the well-known antioxidants BHA and BHT. Our results demonstrate that gamma-oryzanol is an organic radical scavenger able to prevent AMVN-triggered lipoperoxidation. Moreover, when added to oils at concentrations ranging between 2.5 and 10 mmol/kg, gamma-oryzanol shows a dose-dependent increase of the induction times; in particular, it improved the oxidative stability of oils very prone to lipoperoxidation because of their high content of polyunsaturated fatty acids. On the ground of our results, we can conclude that gamma-oryzanol may have a potential application for the stabilization of lipidic raw materials.
γ-谷维素是一种从米糠油中提取的植物甾醇阿魏酸酯混合物，具有广泛的生物活性；特别是，它具有抗氧化特性，常用于化妆品配方中作为防晒剂。本研究的首要目标是利用不同的体外模型系统，如清除稳定的二苯基苦味酰基自由基、羟基自由基和超氧阴离子自由基，以及偶氮化合物AMVN引发的脂质过氧化反应，来阐明γ-谷维素抗氧化活性的分子机制。然后，在氧化加速试验中评估了γ-谷维素对具有药用和化妆品用途的植物油氧化稳定性的影响，并与著名抗氧化剂丁基羟基茴香醚（BHA）和二丁基羟基甲苯（BHT）的效果进行了比较。我们的结果表明，γ-谷维素是一种有机自由基清除剂，能够防止AMVN引发的脂质过氧化。此外，当以2.5至10 mmol/kg的浓度添加到油中时，γ-谷维素的诱导时间呈剂量依赖性增加；特别是，它提高了因富含多不饱和脂肪酸而极易发生脂质过氧化的油的氧化稳定性。基于我们的研究结果，我们可以得出结论，γ-谷维素在脂质原料的稳定化方面可能具有潜在的应用价值。
