SBE is identified as an activator of Fgf21 expression after screening the WAKANYAKU library. (A) The screening of natural medicines from the WAKANYAKU library that can induce Fgf21 expression using an FGF21–luciferase assay. AML12 cells were co-transfected with the reporter vector pGL3-FGF21 and pRL-SV40 as a reference. After 24 h of transfection, cells were treated with 10 µg/mL of natural medicines for 24 h. The luciferase activity was measured and normalized to the renilla luciferase activity. (B) SBE activated FGF21-luciferase activity in AML12 cells. Cells were co-transfected with pGL3-FGF21 and pRL-SV40 vectors. After 24 h of transfection, cells were treated with 10, 50, 100 µg/mL of SBE for 24 h. n = 4 per group. (C) SBE increased Fgf21 expression in AML12 cells. Cells were treated with 50 and 100 µg/mL of SBE for 48 h. n = 4 per group. Data are represented as mean ± SD. * p < 0.05; ** p < 0.01; **** p < 0.0001. Comparisons among multiple groups were assessed using one-way ANOVA, followed by Tukey’s post hoc test.