Figure 5.

The effect of kazinol U on compound C‐ or siAMPK‐induced MITF and tyrosinase expression. (A) B16F10 cells were pretreated with compound C (20 μM) or DMSO for 1 h before treatment with kazinol U (20 μM) or DMSO for 1 h. (B) After pretreatment with kazinol U or DMSO for 1 h, the cells were treated with compound C for 7 h. (C) Cells pretreated with kazinol U or DMSO for 3 h were treated with compound C for 24 h. AMPK phosphorylation and MITF and tyrosinase expression were detected by Western blot analysis. (D) Cells were pretreated with kazinol U (20 μM) or DMSO for 3 h before the addition of compound C (20 μM) for 48 h. Tyrosinase activity was determined by measuring dopachrome formation. (E and F) Cells were transfected with AMPK siRNA for 24 h followed by treatment with kazinol U (20 μM) or DMSO for 1 h (E) or 6 h (F). MITF, AMPK and p‐AMPK expressions were detected by Western blot analysis (A–F: n = 5). One‐way ANOVA with a post hoc Newman–Keuls test was used for the statistical analysis; *P < 0.05.