Quercetin exerts anti-inflammatory effects via inhibiting tumor necrosis factor-α-induced matrix metalloproteinase-9 expression in normal human gastric epithelial cells

Figure 8 Quercetin exhibit antimetastatic activities in vitro. A: Cells were plated in 24-well culture plates, grown to confluence, and starved with serum-free medium for 24 h. Cells were pretreated with a tumor necrosis factor-α (TNF-α) antagonist (1 mM), matrix metallopeptidase-9 inhibitor (5 mM), or quercetin (1 or 10 mM) for 1 h, and monolayer cells were incubated with TNF-α (30 ng/mL) for 24 h as described in the Materials and Methods section; B: One-way ANOVA was used for comparisons between the two groups (^aP < 0.05, ^bP < 0.01 vs control cells). One-way ANOVA was used for comparisons among different treatments (^cP < 0.05, ^dP < 0.01 vs TNF-α-stimulated cells). Data are expressed as the mean ± SEM of three independent experiments. GES-1: Normal human gastric mucosa epithelial cell line; MMP-9: Matrix metallopeptidase-9; MMP9i: MMP-9 inhibitor; TNF-α: Tumor necrosis factor-α.