Protein expression of NRF2 and its target enzymes in HT29 cells treated with QYJD, matrine and oxymatrine. (A) Representative images of Western blots from three independent experiments. Sulforaphane (SFN, 5 μM) was used as a positive control for activating NRF2. β-ACTIN served as a loading control. (B–D) Relative protein levels of Nrf2, HO-1 and NQO1 induced by QYJD, matrine and oxymatrine in HT29 cells. All experiments were performed three times. *P < 0:05, one-way ANOVA; compared to the vehicle-treated group.