The p38 mitogen-activated protein kinase (MAPK) pathway is involved in the demethoxycurcumin (DMC)-mediated induction of heme oxygenase (HO)-1 expression and cell apoptosis. (A,B) HSC-3 cells were exposed to the vehicle or DMC (12.5–50 μM) for 24 h; then, the phosphorylation status of extracellular signal-regulated kinase (ERK)1/2, c-Jun N-terminal kinase (JNK)1/2, and p38 were analyzed by Western blot analysis (A). Quantitative results of phospho-MAPKs, which were adjusted to total MAPKs and are expressed as multiples of induction beyond each respective control (B). Data are presented as the mean ± SD from three independent experiments. * p < 0.05, compared to the vehicle group. (C,D) HSC-3 cells were pretreated with SB203580 (10 μM) or c-Jun N-terminal kinase (JNK)-in-8 (1 μM) for 1 h followed by another 24-h vehicle or DMC (50 μM) treatment. Levels of cleaved caspase-3, -8, and -9, and HO-1 were analyzed by a Western blot analysis (C). Quantitation of Western blots normalized to β-actin was carried out using Image-pro plus processing software (D). Data are presented as the mean ± SD of three independent experiments. * p < 0.05, compared to the vehicle group; #
p < 0.05, compared to the DMC-treated group.