Effect of <i>trans</i>-Octadecenoic Acid Positional Isomers on Tumor Necrosis Factor-α Secretion in RAW264.7 Cells

Abstract

Introduction trans-Fatty acid TFA is a non-conjugated unsaturated fatty acid, interrupted by at least one methylene group with carbon-carbon double bond in the trans configuration 1 . In food, TFAs are mainly composed of 80-90 trans-octadecenoic acid trans-C18:1 , which is made up of 13 different types of positional isomers with doublebond positions in the range from Δ4 to Δ16 2 . TFAs are formed via two major reactions, and the distribution of trans-C18:1 positional isomers differs depending on the TFA formation pathway. The first reaction involves partial hydrogenation of vegetable oil; partially hydrogenated vegetable oil PHVO contains high percentage of elaidic acid trans-9-C18:1 and trans-10-C18:1 2 . The second reaction is biohydrogenation that occurs in the rumen of ruminants such as cows, sheep, and goats. Ruminant fat has high percentage of trans-vaccenic acid trans-11-C18:1 3, 4 . Several studies have shown that cis-fatty acids such as eicosapentaenoic acid, docosahexaenoic acid, and ciseicosenoic acid exert several beneficial effects on human health, including anti-inflammatory and anti-obesity functions 5 7 . In contrast, TFAs have been reported to exhibit