Reprod. Nutr. Dev. 46 (2006) 189-193
DOI: 10.1051/rnd:2006008

In vivo oxidation of [9-¹⁴C] cyclic fatty acids derived from linolenic acid in the rat

Lionel Bretillon^a, Olivier Loreau^b, Jean-Louis Sébédio^c and Frédéric Taran<sup>b

a</sup>  Institut National de la Recherche Agronomique, UMR FLAVIC, équipe OEil et Nutrition, Dijon, France
^b  Commissariat à l'Énergie Atomique, Service des Molécules Marquées, Saclay, Gif-sur-Yvette, France
^c  Institut National de la Recherche Agronomique, Unité du Métabolisme Protéino-Energétique, Clermont-Ferrand, France

(Received 17 October 2005; accepted 19 December 2005; published online 6 April 2006)

Abstract - Heating oils and fats may lead to cyclization of polyunsaturated fatty acids, as for example linolenic acid. Cyclohexenyl and cyclopentenyl fatty acids are subsequently present in some edible oils and these are suspected to induce metabolic disorders. In a previous experiment using [1-¹⁴C] labeled molecules, we published that these cyclic fatty acids are beta oxidized to the same extent as linolenic acid, at least for the first cycle of beta oxidation. However, it is possible that the presence of a ring could alter the ability of the organism to fully oxidize the molecule. In order to test this hypothesis, we assessed the oxidative metabolism of cyclic fatty acids carrying a ¹⁴C atom at the vicinity of the ring. For this purpose, rats were force-fed from 1.1 to 1.3 MBq of a representative fraction of dietary cyclohexenyl cyclic fatty acid monomers of [9-¹⁴C] 9-(6-propyl-cyclohex-3-enyl)-non-8-enoic acids and ¹⁴CO₂ production was monitored for 24h. The animals were then necropsied and the radioactivity was determined in different tissues. No consistent radioactivity was recovered as ¹⁴CO₂ 24h after administration of the molecules. Sixty percent of the radioactivity was recovered in the urine and 30% in the gastrointestinal tract. By combining our previous data on the oxidation of [1-¹⁴C] cyclic fatty acids and the present results, we suggest that cyclohexenyl fatty acids are first beta oxidized in a similar way as linolenic acid and that the remaining molecule carrying the ring is detoxified and eliminated in the urine and feces.

Key words: cyclic fatty acid monomers / linolenic acid / oxidation

Corresponding author: Lionel Bretillon bretillon@dijon.inra.fr

© INRA, EDP Sciences 2006