P-gp protein expression in Caco-2 cells after treatment with NSAS. Cells were exposed for 24 hours to media alone (control), 10 μg/mL, 100 μg/mL and 500 μg/mL NSAS compound A. (A) Representative Western Blot. (B) The data represent the mean ± standard deviation of P-gp protein normalized by the protein expression of actin. There is no statistically significant difference between treatment groups and control. N = 3. (C) Expression profile of mdr-1 gene expression in Caco-2 cells. A sample from each PCR product was subjected to electrophoresis on a 1.5% agarose gel and the fluorescent bands were quantified with UVP-Labworks software. Each value represents the mean ± standard deviation of N = 3.