Rodríguez-Meizoso I, Marin F R, Herrero M, Señorans F J, Reglero G, Cifuentes A, Ibáñez E
Departamento de Caracterización de Alimentos, Instituto de Fermentaciones Industriales (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain.
J Pharm Biomed Anal. 2006 Aug 28;41(5):1560-5. doi: 10.1016/j.jpba.2006.01.018. Epub 2006 Feb 20.
In the present work, oregano leaves (Origanum vulgare L.) are explored as natural source of nutraceuticals with antioxidant activity. To do this, subcritical water extraction (SWE), a new environmentally friendly technique, is employed as extraction procedure and HPLC coupled to DAD is used for the chemical characterization of the extracts. Moreover, the radical scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH) method and the determination of the total phenolic content (measured with the Folin test) are applied to evaluate the antioxidant activity of the extracts. The extraction of antioxidants from oregano leaves by SWE is studied considering different temperatures (25, 50, 100, 150 and 200 degrees C) to investigate the selectivity of the process. The highest antioxidant activity is observed for the extract obtained at the highest temperature, 200 degrees C (EC(50) equal to 10 microg/ml). Moreover, the extraction yield was also the highest (54% dry weight) at these extraction conditions. The total phenolic content showed no differences among the different extracts, concluding that the amount of phenolic compounds extracted was similar but the type and structure of the phenolics was different, providing in this way different antioxidant activity. Some compounds could be tentatively identified, proposing some probable chemical structures for some of them, such as flavanones, dihydroflavonols, favonols and flavones.
在本研究中，牛至叶（牛至属植物）被探索作为具有抗氧化活性的营养保健品的天然来源。为此，采用亚临界水萃取（SWE）这一新型环保技术作为提取方法，并使用与二极管阵列检测器（DAD）联用的高效液相色谱法（HPLC）对提取物进行化学表征。此外，应用自由基清除1,1 - 二苯基 - 2 - 苦基肼（DPPH）法和总酚含量测定（用福林试验测定）来评估提取物的抗氧化活性。考虑不同温度（25、50、100、150和200摄氏度）研究了通过SWE从牛至叶中提取抗氧化剂的过程，以考察该过程的选择性。在最高温度200摄氏度下获得的提取物表现出最高的抗氧化活性（半数有效浓度（EC50）等于10微克/毫升）。此外，在这些提取条件下提取率也是最高的（54%干重）。不同提取物之间的总酚含量没有差异，这表明提取的酚类化合物数量相似，但酚类的类型和结构不同，从而提供了不同的抗氧化活性。可以初步鉴定出一些化合物，并为其中一些提出了一些可能的化学结构，如黄烷酮、二氢黄酮醇、黄酮醇和黄酮。
