Fig. 4 Effect of the compound 3 in Caspase-3 activity in KB cells. Caspase-3 activity was determined by using the Caspase colorimetric assay Kit (SIGMA RBI St. Louis, USA), in KB cells untreated and treated with compound 3 at different concentrations for 72 hrs. Stock solution of the compound was prepared in DMSO and the final concentration of this solvent was kept constant at 0.25%. Control cultures received DMSO alone. Each value represents the mean ± SD of three experiments, performed in quadruplicate. *Significant vs. control untreated cells (p < 0.001).