Fig. 5

Indigo naturalis’ impact on the IL-17 pathway. (a) Down-regulation of interleukin (IL)-17A mRNA in the lesional skin (LS). Indigo naturalis-treated samples (blue filled-circle) are the left columns (week 0 [WK 0]: n = 16; week 8 [WK 8]: n = 14); placebo-treated samples (green triangles) are the middle two columns (WK 0: n = 8; WK 8: n = 7), and baseline nonlesional (NL) samples (gray square) are the right column (n = 23); (b) inhibition of IL-17-induced IL-6 secretion in cultured human keratinocytes. 100 mg/mL of IL-17 is present in all samples except media alone (first column). Compounds are tested in the following order: PD 0325901 1 μg (n = 2), 10 μg (n = 2); Tryptanthrin 0.3 μg (n = 7), 2.5 μg (n = 7) and 10 μg (n = 7). ^*T-test p-value ≤0.05; (c) inhibition of IL-17-induced IL-8 secretion in cultured human keratinocytes. 100 mg/mL of IL-17 is present in all samples except media alone (first column). IL, interleukin; mRNA, messenger RNA; SEM, standard error of mean