ABSTRACT

The aim of this study was to investigate the proapoptotic activity of Thymus capitatus essential oil in either colon cancer stem (CD133þ Colo-320) or nonstem (CD133– Colo-320) cells.

T. capitatus essential oil was obtained by water distillation and analyzed by GC–MS. Cancer stem cells (CD133þ 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.

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 CD133þ and CD133– Colo-320 cells.

We conclude that T. capitatus essential oil increases caspase-3 molecules, which play a crucial role in apoptosis. Interestingly, T. capitatus essential oil is found to be more effective in Colo-320 cells than CD133þ Colo-320 and CD133– Colo-320 cells in terms of apoptosis.