Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan.
J Agric Food Chem. 2011 Mar 9;59(5):1968-73. doi: 10.1021/jf1036307. Epub 2011 Feb 3.
trans-Fatty acids in humans not only may be obtained exogenously from food intake but also could be generated endogenously in tissues. The endogenous generation of trans-fatty acids, especially in the cell membranes induced by radical stress, is an inevitable source for the living species. Thiyl radicals generated from thiols act as the catalyst for the cis-trans isomerization of fatty acids. Arachidonic acid (5c,8c,11c,14c-20:4) with only two of the four double bonds deriving from linoleic acid in the diet can be used to differentiate the exogenous or endogenous formation of double bonds. The aim of this study is to evaluate the effective compounds in preventing thiyl radical-induced trans-arachidonic acid formation during UV irradiation in vitro. The trans-arachidonic acids were found to be 75% after 30 min UV irradiation of all-cis-arachidonic acid. Myricetin, luteolin, and quercetin had the highest thiyl radical scavenging activities, whereas sesamol, gallic acid, and vitamins A, C, and E had the lowest. The structures of flavonoids with higher thiyl radical scavenging activities were a 3',4'-o-dihydroxyl group in the B ring and a 2,3-double bond combined with a 4-keto group in the C ring. These effective compounds found in the present work may be used as lead compounds for the potential inhibitors in the formation of trans-fatty acids in vivo.
反式脂肪酸不仅可以从食物摄入中外源性获得，还可以在组织内内源性生成。反式脂肪酸的内源性生成，特别是在自由基应激诱导的细胞膜中，是生物物种不可避免的来源。巯基自由基可以作为脂肪酸顺反异构化的催化剂。来源于饮食中亚油酸的只有两个双键的花生四烯酸（5c、8c、11c、14c-20:4）可以用来区分双键的外源性或内源性形成。本研究旨在评估有效化合物在体外紫外线照射下预防巯基自由基诱导的反式花生四烯酸形成的能力。在对全顺式花生四烯酸进行 30 分钟紫外线照射后，发现反式花生四烯酸的含量为 75%。杨梅素、木犀草素和槲皮素具有最高的巯基自由基清除活性，而芝麻酚、没食子酸以及维生素 A、C 和 E 则具有最低的活性。具有较高巯基自由基清除活性的黄酮类化合物的 B 环上具有 3'、4'-o-二羟基，C 环上具有 2、3-双键和 4-酮基。本研究中发现的这些有效化合物可以作为体内反式脂肪酸形成潜在抑制剂的先导化合物。
