Characterization of Trans Eicosapentaenoic Acid Isomers: Oxidative Stability and Anti-Inflammatory Activity

Although trans geometric isomers of unsaturated fatty acids are formed during heat treatment, little is known about the physicochemical properties and the bioactivities of trans eicosapentaenoic acid (TEPA). We examined the oxidative stability and the anti-inflammatory activity of TEPA prepared using p-toluenesulfinic acid. TEPA was more stable to oxidation induced by radical generators than eicosapentaenoic acid (EPA) in organic and in aqueous solutions, and was less suitable as a substrate for 15-lipoxygenase oxidation than was EPA. These results suggest that the trans conformation may be a more stable structure to oxidation. In addition, the release of leukotriene B4 (LTB4) from Ca-ionophore-stimulated rat peritoneal exudate cells (PEC) was not affected by treatment with TEPA, and TEPA was taken up into PEC at lower levels compared to EPA. These results suggest that dietary TEPA has different physiological effects than EPA.