Fig. 6

Quince peel polyphenols markedly reduce tumor cell colony formation and potentiates 5-fluorouracil efficacy. Peph effect on LS174 colony-forming capacity was measured using clonogenic survival assay. LS174 cells were treated with vehicle (control) or Peph (5 µg/ml) associated or not with 5-FU (50 µM) for 72 h. After removal of the medium, 2000 viable cells from each group were cultured in six-well plates for additional 10 days. Colonies were stained with crystal violet. Each assay was photographed (a) and the number of colonies was analyzed and scored by Image J quantification software. Results are expressed as the number of colony forming cells per well and normalized to control (vehicle) in percentage and represented as mean ± SE of three independent experiments, each performed at least in duplicate (b). Asterisk represents a significant difference (*p < 0.05) as compared to no treatment group