LC/MS of Large Atherogenic Lipid Oxidation Products

描述（由申请方提供）：三酰基甘油（TAG）含有不饱和位点，当暴露于空气或加热时，这些位点易氧化。这些TAG形成各种初级氧化产物，其含有具有多个官能团的脂肪酸，例如氢过氧化物、环氧化物、酮和醇。脂肪酸氧化产物已被证明代表显著的动脉粥样硬化风险。氧化产物已被证明是纳入刷状缘细胞，然后进入低密度脂蛋白（LDL）。新的分析方法，P.I.是开创性的，允许大，高分子量（MW）TAG氧化产物（TAGOX），由几个氧化TAG连接在一起，以直接识别的第一次。这些大的寡聚体TAGOX值得进一步研究，因为它们通常作为典型的美国饮食的一部分食用，但它们以前从未被表征过。我们建议使用液相色谱电喷雾电离质谱（ESI-MS）分析的大型含氧低聚物产生的加热油。我们将描述完整的低聚物含有两个（二聚体），三个（三聚体）或四个（四聚体）三酰基甘油共价键合在一起。这些分子含有活性氧官能团，可以使氧化脂肪酸结合到生物组织中，如低密度脂蛋白（LDL）。我们将分析加热0小时的三油酸甘油酯（橄榄油和菜籽油的主要成分）的氧化产物，1小时，3小时，和6小时，以确定由于氧化引起的降解的开始和程度。我们将检查用0 ppm、100 ppm和400 ppm α生育酚（维生素E）处理的加热油样品，以证明通过加入抗氧化剂可以显著降低氧化。这项研究将首次直接鉴定高分子量氧化产物的特定分子种类。我们建议使用LC/MS来研究由模型油形成的产物以及从加热油中油炸的薯片中提取的产物。这些高分子量氧化低聚物的表征将为膳食油被氧化并可用于掺入生物组织的机制提供前所未有的见解。

DESCRIPTION (provided by applicant): Triacylglycerols (TAG) contain sites of unsaturation that are susceptible to oxidation when exposed to air, or when heated. These TAG form a variety of primary oxidation products that contain fatty acids with multiple functional groups, such as hydroperoxides, epoxides, ketones and alcohols. Fatty acid oxidation products have been shown to represent a significant atherosclerotic risk. Oxidation products have been shown to be incorporated into brush border cells, and then into low-density lipoprotein (LDL). New analytical methodologies that the P.I. is pioneering have allowed large, high molecular weight (MW) TAG oxidation products (TAGOX), made from the joining together of several oxidized TAG, to be directly identified for the first time. These large, oligomeric TAGOX deserve further study because they are routinely consumed as part of the typical American diet, yet they have never before been characterized. We propose to use liquid chromatography coupled with electrospray ionization-mass spectrometry (ESI-MS) for analysis of the large oxygen-containing oligomers produced by heated oils. We will characterize intact oligomers containing two (dimers), three (trimers) or four (tetramers) triacylglycerols covalently bonded together. These molecules contain oxygen functional groups that are reactive and could allow oxidized fatty acids to be incorporated into biological tissue, such as low-density lipoprotein (LDL). We will analyze oxidation products from triolein (the major component in olive and canola oils) heated for 0 hr., 1 hr., 3 hr., and 6 hr. to determine the onset and extent of degradation due to oxidation. We will examine heated oil samples treated with 0 ppm, 100 ppm, and 400 ppm alpha tocopherol (vitamin E) to demonstrate that oxidation can be significantly reduced by incorporation of antioxidants. This research will represent the first time that the specific molecular species of high molecular weight oxidation products have been directly identified. We propose to use LC/MS to study the products formed by model oils and also the products extracted from potato chips fried in the heated oils. The characterization of these high molecular weight oxidized oligomers will provide unprecedented insight into the mechanisms by which dietary oils are oxidized and made available for incorporation into biological tissue.