Dose-dependent activation of caspase-3 in carvacrol-treated MDA-MB-231/Dox cells. Caspase-3 activity percentage in MDA-MB-231/Dox cells treated with different concentrations of carvacrol for 24 h was determined by caspase-3 activity assay. Values are presented as mean ± SD, and symbol asterisk indicates significant (** p < 0.01, *** p < 0.001) difference as compared to the control cells.