Genetically Modified Rapeseed Oil Containing cis-9,trans-11,cis-13-Octadecatrienoic Acid Affects Body Fat Mass and Lipid Metabolism in Mice

Abstract

Punicic acid, one of the conjugated linolenic acid (CLN) isomers, exerts a body-fat reducing effect. Although punicic acid is found in pomegranate and Tricosanthes kirilowii seeds, the amount of this fatty acid is very low in nature. The goal of this study was to produce a transgenic oil containing punicic acid. A cDNA encoding conjugase that converts linoleic acid to punicic acid was isolated from T. kirilowii, and the plant expression vector, pKN-TkFac, was generated. The pKN-TkFac was introduced into Brassica napus by Agrobacterium-mediated transformation. As a result, a genetically modified rapeseed oil (GMRO) containing punicic acid was obtained, although its proportion to the total fatty acids was very low (approximately 2.5%). The effects of feeding GMRO in ICR CD-1 male mice were then examined. Wild-type rapeseed (B. napus) oil (RSO) containing no CLN was used as a control oil. For reference oils, RSO-based blended oils were prepared by mixing with different levels of pomegranate oil (PO), either 2.5% (RSO + PO) or 5.0% (RSO + 2PO) punicic acid. Mice were fed purified diets containing 10% of either RSO, RSO + PO, RSO + 2PO, or GMRO for 4 weeks, and dietary PO dose-dependently reduced perirenal adipose tissue weight with a significant difference between the RSO group and the RSO + 2PO group. GMRO, as compared to RSO, lowered the adipose tissue weight to the levels observed with RSO + 2PO. The liver triglyceride level of the RSO + 2PO and GMRO groups but not that of the RSO + PO group was lower than that of the RSO group. The RSO + 2PO and GMRO groups, but not the RSO + PO group, had increased carnitine-palmitoyltransferase activity in the liver and brown adipose tissue. These results showed that dietary GMRO, even at a dietary punicic acid level as low as 0.25 wt % of diet, reduced body fat mass and altered liver lipid metabolism in mice and was more effective than an equal amount of punicic acid from PO.

Effect of pomegranate seed oil on hyperlipidaemic subjects: a double-blind placebo-controlled clinical trial

“…Current data on the effect of PSO on lipid concentration and metabolism are controversial (8,9,17) . Similar to our findings, the liver accumulation of TAG was reduced by PSO administration (8,18) ; a plausible mechanism, demonstrated in an in vitro study, that 9-cis, 11-trans, 13-cis CLN suppressed cellular synthesis of TAG in HepG2 cells (19) .…”

A comparison between CLNA and CLA effects on body fat, serum parameters and liver composition

“…All three groups were given semipurified high-fat diets consisting of 200 g/kg casein and 4 g/kg L-methionine (Sigma, St. Louis, MO, USA), 200 g/kg wheat starch (Vencasser, Bilbao, Spain), 409 g/kg sucrose (local market), 30 g/kg cellulose (Vencasser, Bilbao, Spain) and 4 g/kg choline chlorhydrate (Sigma, St. Louis, MO, USA) for 7 weeks. Vitamin and mineral mixes were formulated according to AIN-93 guidelines (13) and supplied by ICN Pharmaceuticals (Costa Mesa, CA, USA).…”

Potential health benefits of conjugated trienoic acids

“…The genetically modified rapeseed contained punicic acid, although the proportion of punicic acid to the total fatty acids was still very low, approx. 2.5% (1). This is only the first attempt, and efforts to produce a transformed plant accumulating higher levels of punicic acid are expected.…”