Xu Zhidong, Harvey Kevin A, Pavlina Thomas M, Zaloga Gary P, Siddiqui Rafat A
Cellular Biochemistry Laboratory, Methodist Research Institute, Indiana University Health, Indianapolis, Indiana.
Baxter Healthcare Corporation, Deerfield, Illinois.
JPEN J Parenter Enteral Nutr. 2016 Jul;40(5):672-81. doi: 10.1177/0148607114547537. Epub 2014 Aug 28.
Tocopherols and tocotrienols possess vitamin E activity and function as the major lipid-soluble antioxidants in the human body. Commercial lipid emulsions are composed of different oils and supply different amounts of vitamin E. The objective of this study was to measure all 8 vitamin E homologs within 4 different commercial lipid emulsions and evaluate their distribution in guinea pig tissues.
The distribution of vitamin E homologs within plasma and guinea pig tissues was determined using a high-performance liquid chromatography (HPLC) system. Lipid hydroperoxides in lipid emulsions were determined using a commercial kit (Cayman Chemical Company, Ann Arbor, MI), and malondialdehyde tissue levels were determined using an HPLC system.
The lipid emulsions contained variable amounts of tocopherols, which were significantly different between emulsions. Tocotrienols were present at very low concentrations (≤0.3%). We found no correlation between the amount of vitamin E present in the lipid emulsions and lipid peroxidation. Hydroperoxides were the lowest with an olive oil-based emulsion and highest with a fish oil emulsion. The predominant vitamin E homolog in guinea pig tissues was α-tocopherol. No tissues had detectable levels of tocotrienols. Vitamin E levels (primarily α-tocopherol and γ-tocopherol) were highly variable among organ tissues. Plasma levels were a poor reflection of most tissue levels.
Vitamin E levels within different lipid emulsions and plasma/tissues are highly variable, and no one tissue or plasma sample serves as a good proxy for levels in other tissues. All study emulsions were well tolerated and did not significantly increase systemic lipid peroxidation.
生育酚和生育三烯酚具有维生素E活性，是人体内主要的脂溶性抗氧化剂。商业脂质乳剂由不同的油类组成，提供不同量的维生素E。本研究的目的是测定4种不同商业脂质乳剂中的所有8种维生素E同系物，并评估它们在豚鼠组织中的分布。
使用高效液相色谱（HPLC）系统测定血浆和豚鼠组织中维生素E同系物的分布。使用商业试剂盒（开曼化学公司，安阿伯，密歇根州）测定脂质乳剂中的脂质氢过氧化物，使用HPLC系统测定丙二醛组织水平。
脂质乳剂中生育酚含量各不相同，不同乳剂之间存在显著差异。生育三烯酚的浓度非常低（≤0.3%）。我们发现脂质乳剂中维生素E的含量与脂质过氧化之间没有相关性。以橄榄油为基础的乳剂中氢过氧化物含量最低，鱼油乳剂中最高。豚鼠组织中主要的维生素E同系物是α-生育酚。没有组织检测到生育三烯酚。维生素E水平（主要是α-生育酚和γ-生育酚）在器官组织中差异很大。血浆水平不能很好地反映大多数组织的水平。
不同脂质乳剂以及血浆/组织中的维生素E水平差异很大，没有一个组织或血浆样本能够很好地代表其他组织中的水平。所有研究中的乳剂耐受性良好，不会显著增加全身脂质过氧化。
