Fig. 5. Luteolin, quercetin or myricetin downregulates the phosphorylation of Smad2/3.
a−c Western blotting and densitometric analysis demonstrate that luteolin, quercetin or myricetin dose-dependently inhibits the expression of phosphorylated Smad2/3 without affecting the other factors in TGF-β/Smads signaling pathway or Smad1/5/9 in BMP signaling. d Representative images of immunofluorescence staining of human dermal fibroblasts exhibit a significant reduction in TGF-β1-induced Smad3 (green) translocation into the nuclei. e Luteolin, quercetin or myricetin has no significant impact on the expression of TGF-β1 based on ELISA assay. f Luteolin, quercetin or myricetin does not induce notable effect on the expression of TGFβRI or TGFβRII according to western blotting. Data are the mean ± SD (three independent experiments); *P < 0.05, **P < 0.01, ***P < 0.001