Proapoptotic and Anticancer Potentials of Thymus capitatus Essential Oil on Colon Cancer Stem Cells

BACKGROUND/AIMS The aim of this study was to investigate the proapoptotic activity of Thymus capitatus essential oil in either colon cancer stem (CDI33+ Colo-320) or nonstem (CDI33- Colo-320) cells. MATERIAL and METHODS T. capitatus essential oil was obtained by water distillation and analyzed by GC-MS. Cancer stem cells (CDI33+ Colo-320) were obtained from the Colo-320 cells by the MiniMACS system. Proapoptotic activity of T capitatus essential oil was investigated by immunocytochemistry using antibodies directed against caspase-3 and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. RESULTS Caspase-3 immunoreactivity was significantly increased in 0.5% dilution T. capitatus essential oil-treated Colo-320 cells for 48 hours Moreover, the number of TUNEL positive cells was significantly higher in Colo-320 cells when compared with CDI33+ and CDI33- Colo320 cells. CONCLUSION We conclude that T capitatus essential oil increases caspase-3 molecules, which play a crucial role in apoptosis. Interestingly, T capita- tus essential oil is found to be more effective in Colo-320 cells than CDI33+ Colo-320 and CDI33- Colo-320 cells in terms of apoptosis.