Decreased production of interleukin-6 and prostaglandin E2 associated with inhibition of Δ-5 desaturation of ω6 fatty acids in mice fed safflower oil diets supplemented with sesamol

The differences in the immune responses in mice fed sesame oil diets and those fed sesamin may be attributed to the presence of other lignans in the non-fat portion of the oil. The fatty acid composition (mean +/- SD mel. %) of liver membrane phospholipids and the levels of endotoxin-induced prostaglandin (PG) E-2, interleukin (IL)-6, IL-10, IL-12 and tumor necrosis factor (TNF)-alpha were determined in mice fed diets supplemented with 5% safflower oil (SO) in the absence or presence of 1% sesamol. The levels of dihomo-gamma-linolenic acid (20:3w6) were markedly higher (P < 0.025) in the livers from mice fed sesamol supplemented SO diets (1.6 +/- 0.1) compared to the controls (1.4 +/- 0.1). These data suggest that sesamol or its metabolite could inhibit the in vivo Delta-5 desaturation of w6 fatty acids. Further, in animals fed sesamol supplemented SO diets, the levels of PGE, (228 +/- 41 pg/ml) were markedly lower (P < 0.01) compared to those fed SO diet alone (1355 +/- 188 pg/ml). Concomitantly, the concentrations of IL-6 were also lower (P < 0.01) in mice fed sesamol diet (63 +/- 11 ng/ml) compared to the controls (143 +/- 22 ng/ml). A marked reduction in the levels of PGE, in animals fed sesamol diets suggests that sesamol or its metabolite could inhibit the activity of cycloxygenase enzyme. (C) 1999 Harcourt Publishers Ltd.