Alpha-eleostearic acid (9Z11E13E-18:3) is quickly converted to conjugated linoleic acid (9Z11E-18:2) in rats.
We previously showed that alpha-eleostearic acid (alpha-ESA; 9Z11E13E-18:3) is converted to conjugated linoleic acid (CLA; 9,11-18:2) in the liver and plasma of rats that were given diets including 1% alpha-ESA for 4 wk. In this study, we investigated this phenomenon in detail. First, the chemical structure of CLA produced by alpha-ESA administration was determined. After alpha-ESA was orally administered to rats, CLA in rat liver was isolated by HPLC. The positional and geometric isomerism was determined using GC-EI/MS and (13)C-NMR, respectively, and the CLA generated in rats after alpha-ESA feeding was confirmed to be 9Z11E-CLA. Next, the concentrations of alpha-ESA and CLA were determined 0, 3, 6, and 24 h after oral administration of alpha-ESA to rats. Moreover, we also investigated whether enteric bacteria are involved in the conversion of alpha-ESA to CLA using germ-free rats. alpha-ESA was orally administered to germ-free and normal rats and alpha-ESA and CLA were detected in the organs of both groups. In addition, to confirm that this reaction was enzyme-mediated, alpha-ESA was reacted with tissue homogenates (liver, kidney, and small intestine mucous) and coenzymes (NADH, NAD(+), NADPH, and NADP(+)), and the enzyme activities were estimated from the amount of CLA produced. CLA was detected when alpha-ESA was reacted with liver, kidney, and small intestine mucous homogenates and a coenzyme (NADPH). These results indicated that alpha-ESA is converted to 9Z11E-CLA in rats by a Delta13-saturation reaction carried out by an NADPH-dependent enzyme.
Food & Biodynamic Chemistry Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan.
Tsuyoshi
T
Tsuzuki
Yoshiko
Y
Tokuyama
Miki
M
Igarashi
Kiyotaka
K
Nakagawa
Yusuke
Y
Ohsaki
Michio
M
Komai
Teruo
T
Miyazawa
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D044243:Linoleic Acids, Conjugated / Q000097:blood / Q000378:metabolism*; D008042:Linolenic Acids / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D044243:Linoleic Acids, Conjugated; D008042:Linolenic Acids; C004934:eleostearic acid