The antiadipogenic activity of conjugated linoleic acids (CLA) in the form of phosphatidylcholine-bound (CLA-PC) or free fatty acids (FFA; CLA-FFA) was evaluated using 3T3-L1 adipocytes. Phosphatidylcholine from soya (soy-PC) was used as the comparison of PC form. Both the lipid accumulation and activity of glycerol-3-phosphate dehydrogenase were measured to determine lipogenesis, whereas the glycerol content was measured to evaluate lipolysis. The CLA uptake also measured to find out the utilization of CLA by the cells. As a results, lipid accumulation in 3T3-L1 adipocytes was inhibited in a dose-dependent manner following treatment with CLA-PC (50-400 μM). Both CLA-PC and soy-PC significantly suppressed lipid accumulation compared with CLA-FFA, even though the amount of CLA in CLA-PC was a half than CLA-FFA. The CLA uptake of PC form was superior to FFA form, however, no difference was noted between CLA-PC and soy-PC. These forms exerted their antiadipogenic activity via the suppression of lipogenesis, and not by increasing lipolysis. Short-term treatment, especially in the middle stage of differentiation, was more effective than long-term treatment; especially for CLA-FFA. The antiadipogenic effect of CLA-PC was partially attributed to the chemical structure of the PC molecule. These results provide important information for the utilization of physiologically functional fatty acids and particularly CLA in the food and medical fields.
Keywords: antiobesity; conjugated linoleic acid; phosphatidylcholine.