Curcuma zedoaria (Berg.) Rosc. essential oil and paclitaxel synergistically enhance the apoptosis of SKOV3 cells.

Curcuma zedoaria (Berg.) Rosc. essential oil (CZEO) is the major component of Curcuma zedoaria (Berg.) Rosc., a traditional medicine with antitumor activity. Paclitaxel (PTX) is a first-line chemotherapeutic agent used to treat patients with ovarian cancer. These compounds directly target nuclear DNA, in order to suppress or inhibit tumor cell growth. The present study aimed to determine the synergistic antitumor effects of CZEO and PTX on the SKOV3 human ovarian cancer cell line. SKOV3 cells were treated with CZEO, PTX or a combination of the two and cell viability was detected using cell counting kit-8. In addition, flow cytometry was used to determined cell apoptosis as well as for cell cycle analysis. The morpho-logical changes of apoptosis were assessed using Hoechst 33342 staining and the expression levels of apoptotic pathway proteins, including caspase-3 and poly (ADP-ribose) polymerase (PARP), were quantified using western blot analysis. The cell viability assay indicated that either of these compounds alone or in combination suppressed the growth of SKOV3 cells. Furthermore, flow cytometric analysis indicated that treatment with a combination of CZEO and PTX resulted in increased inhibition of proliferation and induction of apoptosis of SKOV3 cells, as compared with treatment with either of the compounds alone. In addition, the protein expression levels of caspase-3 were increased following treatment with a combination of CZEO and PTX. The results of the present study suggested that CZEO and PTX synergistically enhanced the inhibition of SKOV3 proliferation, and the possible underlying mechanism may be the induction of cell apoptosis and cell cycle arrest. This therefore indicated that PTX supplemented with CZEO may be an effective treatment strategy to decrease the dose and toxicity of PTX.