Grapefruit oil attenuates adipogenesis in cultured subcutaneous adipocytes.

We investigated the effects of different essential oils on adipogenesis in rat subcutaneous adipocytes. Subcutaneous preadipocytes were cultured in Dulbecco's Modified Eagle Medium (DMEM) containing insulin, transferrin, fibroblast growth factor, dexamethasone, indomethacin, fetal bovine serum, and an essential oil at 37 °C in 5 % CO 2 to induce their differentiation. After 7 days, the number of viable cells and the amount of triglycerides accumulated in the cells were determined. Differentiation markers such as the enzymatic activity of glycerol-3-phosphate dehydrogenase (GPDH) and the expression of GPDH and peroxisome proliferator-activated receptor γ (PPAR γ) genes were also measured, as well as the intracellular Ca 2+ levels. We found that grapefruit oil inhibited the accumulation of triglycerides in a dose-dependent manner at concentrations of 50 to 400 μg/mL. Furthermore, it suppressed the expression of GPDH and caused a 70 % decrease in the enzymatic activity of GPDH at a concentration of 50 μg/mL. Grapefruit oil also caused a nearly 2-fold increase in the intracellular concentration of Ca 2+ and suppressed the expression of PPAR γ genes. Our results demonstrate that grapefruit oil efficiently inhibits adipogenesis in cultured subcutaneous preadipocytes and adipocytes.