Kinase activities involved in luteolin-induced ARE transcriptional activity. (A) Effect of luteolin on the kinase activities. Activities of p38α, AMPK A1/B1/G2, and AKT1 were measured in the presence of luteolin at various concentrations (0.01, 0.1, 1, 5, 10, and 25 μM) and expressed relative to control (without luteolin treatment). (B) Relative ARE-luciferase activity in HCT116-ARE cells. Cells were treated with 5 or 12.5 μM luteolin in the absence or presence of LY294002 (a PI3K/AKT inhibitor, 2.5 μM) and compound C (an AMPK inhibitor, 1 μM) for 24 h, and analyzed for ARE-luciferase activity. Sulforaphane (SFN, 3 μM) was used as a positive control to induce ARE activity. The data are expressed as the mean ± SEM (n = 6). A significant difference between the groups at p < 0.05 was indicated by an asterisk (*). Data are presented as the mean ± SD (n = 4). Significant differences compared to the control at p < 0.05 are indicated by an asterisk (*) or a hashtag (#).