TABLE 1

Selectivity of the neolignans toward PPAR subtype (-α, -β/δ, -γ)-driven luciferase reporter transactivation

HEK-293 cells were transiently cotransfected with an expression plasmid for the respective PPAR subtype, a reporter plasmid containing PPRE coupled to the luciferase reporter, and EGFP as internal control. Cells were stimulated with the indicated concentrations of the respective compounds for 18 h. Luciferase activity was normalized by the EGFP-derived fluorescence, and the result was expressed as fold induction compared with the negative control (DMSO vehicle treatment). The selective agonists for PPARα (GW7647), PPARβ/δ (GW0742), and PPARγ (pioglitazone) were used to verify the specificity of the respective assays. EC₅₀ and maximal fold activation were determined by GraphPad Prism using settings for nonlinear regression with sigmoidal dose response and variable slope. The data shown represent means of three to five independent experiments, each performed in quadruplet. Analysis of variance showed statistical significance with P < 0.001 for the presented effects.