rumenic-acid and eleostearic-acid

Our previous studies have shown that α-eleostearic acid (α-ESA; cis-9, trans-11, trans-13 (c9,t11,t13)-conjugated linolenic acid (CLnA)) is converted into c9,t11-conjugated linoleic acid (CLA) in rats. Furthermore, we have demonstrated that the conversion of α-ESA into CLA is a nicotinamide adenine dinucleotide phosphate (NADPH)-dependent enzymatic reaction, which occurs mostly in the rat liver. However, the precise metabolic pathway and enzyme involved have not been identified yet. Therefore, in this study we aimed to determine the role of cytochrome P450 (CYP) in the conversion of α-ESA into c9,t11-CLA using an in vitro reconstitution system containing mouse hepatic microsomes, NADPH, and α-ESA. The CYP4 inhibitors, 17-ODYA and HET0016, performed the highest level of inhibition of CLA formation. Furthermore, the redox partner cytochrome P450 reductase (CPR) inhibitor, 2-chloroethyl ethyl sulfide (CEES), also demonstrated a high level of inhibition. Thus, these results indicate that the NADPH-dependent CPR/CYP4 system is responsible for CLA formation. In a correlation analysis between the specific activity of CLA formation and Cyp4 family gene expression in tissues, Cyp4a14 and Cyp4f13 demonstrated the best correlations. However, the CYP4F substrate prostaglandin A

Topics: Animals; Cytochrome P450 Family 4; Gene Expression; In Vitro Techniques; Linoleic Acids, Conjugated; Linolenic Acids; Mice, Inbred ICR; Microsomes, Liver; NADP

Dietary oils containing large amounts of conjugated linolenic acids (CLnA) may be regarded as a source of conjugated linoleic acids (CLA), which have been suspected to bear health-promoting properties. Indeed, CLnA can be converted into CLA in mammals. The objective of the present study was to investigate the uptake of CLnA and their metabolism into CLA in Caco-2 cells, as a validated in vitro model of the intestinal barrier. Caco-2 cells were incubated for 24 h in the presence of either α-eleostearic, β-eleostearic, catalpic or punicic acid. We first observed that Caco-2 cells take these CLnA up at different rates and then convert them but with varying efficiency depending on the structure of the Δ13 double bond. Finally, the distribution of CLnA between neutral lipids (NL) and phospholipids appeared to be linked to their number of trans double bonds: the higher the number, the higher the accumulation in the NL fraction.

Topics: Absorption; Caco-2 Cells; Chromatography, High Pressure Liquid; Culture Media, Serum-Free; Enterocytes; Esterification; Gas Chromatography-Mass Spectrometry; Humans; Intestinal Absorption; Kinetics; Linoleic Acids, Conjugated; Linolenic Acids; Molecular Structure; Oxidation-Reduction; Phospholipids; Solid Phase Extraction; Stereoisomerism; Triglycerides