Figure 1.

Decrease in claudin-2 expression by quercetin. (A and B) A549 cells were incubated in the absence (−) and presence (+) of 50 μM quercetin for the periods indicated. Cytoplasmic fractions were immunoblotted with anti-claudin-2, claudin-1, or β-actin antibody. The expression of claudin-1 and claudin-2 was represented relative to the values in 0 h; (C) Cells were incubated with quercetin at the indicated concentrations for 24 h. Cytoplasmic fractions were immunoblotted with anti-claudin-1, claudin-2, or β-actin antibody. The expression of claudin-1 and claudin-2 was represented relative to the values in 0 μM. n = 3–4. ** p < 0.01 significantly different from −quercetin. ^## p < 0.01 significantly different from 0 μM. NS, not significantly different.