Figure 4.

Activation of Nrf2 by crocin. (a) RAW 264.7 cells were incubated with the indicated concentrations of crocin for 3 h (upper panel) or with 500 μM crocin for various periods (lower panel), after which nuclear extracts were harvested and assayed by Western blotting. TATA binding protein (TBP) was used as a loading control. (b) Cells were transfected with ARE-luciferase construct and then treated with the indicated concentration of crocin. Equal amounts of cell extracts were then assayed for dual luciferase activity. *P < 0.05 versus the group treated with PBS (vehicle).