In vitro synergistic antiproliferative effect of ISBn combination on growing and differentiated Caco-2 cells. CI/fractional effect curves showed the CI versus the fraction of cells affected/killed by polydatin and resveratrol in combination for the growing ( panel A) and differentiated Caco-2 cell lines ( panel B). Combination analysis was done using the method described by Chou and Talalay (see Materials and methods). Combinations were synergistic when CI were <0.8. Representative experiment carried out at least twice for each cell line; in the figure the mean CI50 were reported.