Carvacrol induces mitochondria-mediated apoptosis in HL-60 promyelocytic and Jurkat T lymphoma cells.

The aim of the present study was to investigate the effect of carvacrol, a phenolic monoterpenoid on the induction of apoptosis in HL-60 (Human acute promyelocytic leukemia cells) and Jurkat (human T lymphocyte cells) cells. Carvacrol showed a potent cytotoxic effect on both cells with dose-dependent increase in the level of free radical formation as measured by an oxidation sensitive fluorescent dye, 2,7-dichlorodihydrofluorescein diacetate (H2DCFDA) levels. The reduction in the level of antioxidants such as catalase (CAT) and superoxide dismutase (SOD) (P<0.05) was observed in carvacrol-treated cells. The major cytotoxic effect appears to be intervened by the induction of apoptotic cell death as assessed by annexin-V labeling assay using flow cytometry. Western blot analysis showed that Bax expression was increased, whereas Bcl-2 expression was significantly decreased in carvacrol exposed HL-60 cells and Jurkat cells. Further studies revealed that the dissipation of mitochondrial membrane potential of intact cells was accompanied by the activation of caspase-3. Our results found that the potential mechanism of cellular apoptosis induced by carvacrol is mediated by caspase-3 and is associated with the collapse of mitochondrial membrane potential, generation of free radicals, and depletion of the intracellular antioxidant pool.