Fig. 2.

Effects of the AC-rich mix, PCA, and 3-O-glucosides of cyanidin, delphinidin, and peonidin on TNFα-induced permeabilization of Caco-2 cell monolayers. Caco-2 cell monolayers were pre-incubated for 24 h with IFNγ (10 ng/ml) to upregulate the TNFα receptor. Then, the following compounds were added to the upper chamber and cells incubated for 30 min: A,B- 0.5–5 μg AC mix/ml or C,D- the concentration of the individual components present in the mix at a 5 μg AC/ml concentration: 0.5 μM PCA, 1 μM cyanidin-3-O-glucoside, 0.5 μM delphinidin-3-O-glucoside, or 0.1 μM peonidin. TNFα (5 ng/ml) was subsequently added to the lower chamber and cells incubated for further 6 h. Caco-2 cell monolayer permeability was evaluated by measuring (A,C) FITC-dextran paracellular transport (FITC-Dextran) and (B,D) TEER. Basal TEER values were 350–420 Ω cm² and basal average FITC-dextran clearance value was 65 nl. h⁻¹.cm⁻². Results are shown as mean ± SE of 4–6 independent experiments. Results (A.U.: arbitrary units) were normalized to control values (1, dashed line). Values having different superscripts are significantly different (p < 0.05, One-way ANOVA).