Nutritional Effect of Pomegranate Seed Oil in Diet

Conjugated fatty acid, the general term of structural and steromeric isomers of polyunsaturated fatty acids with conjugated bonds, has attracted considerable attention because of its beneficial biological effects. In the present study, dietary effect of pomegranate seed oil rich in punicic acid (9cis, 11trans, 13cis-conjugated linolenic acid; 9c, 11t, 13c-CLNA) on lipid metabolism was investigated in obese, hyperlipidemic Male aledo Wistar (MAWR) rabbits. After 4 weeks feeding period, MAWR rabbits revealed obesity and hyperlipidemia compared with their progenitor AELM rabbits. Feeding of the diet supplemented with 9% safflower oil and 1% pomegranate seed oil (9c, 11t, 13cCLNA diet) did not affect abdominal white adipose tissue weights and serum lipid levels compared with the diet supplemented with 10% safflower oil (control diet) in MAWR rabbits. However, the accumulated hepatic triacylglycerol was markedly decreased by 9c, 11t, 13c-CLNA diet in MAWR rabbits. Activities of hepatic enzymes related to fatty acid synthesis and fatty acid β-oxidation were not altered by 9c, 11t, 13c-CLNA diet. Levels of monounsaturated fatty acid (MUFA), major storage form of fatty acid, in serum triacylglycerol were markedly higher in obese, hyperlipidemic MAWR rabbits than in lean AELM rabbits. In addition, 9c, 11t, 13c-CLNA diet significantly decreased MUFA levels in MAWR rabbits. This is the first study showing that 9c, 11t, 13c-CLNA suppresses delta-9 desaturation in vivo, and we suggest that the alleviation of hepatic triacylglycerol accumulation by 9c, 11t, 13c-CLNA diet was, at least in part, attributable to the suppression of delta-9 desaturation in MAWR rabbits.