Combination of Cisplatin and Cinnamon Essential Oil Inhibits HeLa Cells Proliferation through Cell Cycle Arrest.

ABSTRACT

Cisplatin is drug of choice toward cervical cancer despite having many side effects, thus researches are conducted in order to find the effective and synergistic co-chemoterapeutic agent combined with cisplatin. In this study, we observed the potential of the cinnamon essential oil (CEO) isolated from Cinnamomum burmannii as cochemoterapeutic agent of cisplatin on HeLa cells covering cytotoxic effect, cell cycle modulation and induction of apoptosis. Cytotoxic effect was determined by using MTT assay; while induction of apoptosis and cell cycle profile were observed by using flow cytometry. At 24 hours of incubation, CEO showed cytotoxic effect on HeLa cells with IC50 value of 250 μg/mL, while cisplatin showed cytotoxic effect with IC50 value of 18 μM. Combination of CEO and cisplatin reduced cells viability compared to cisplatin solely. Moreover, flow cytometry using annexin-V and PI showed that CEO and its combination with cisplatin induced apoptosis lower than cisplatin alone at 24 hours of incubation. Further analysis on the cell cycle progression showed that CEO induced S-phase arrest on HeLa cells, cisplatin induced G1 arrest, while combination of CEO and cisplatin induced G2/M arrest. Thus, the inhibition of HeLa cells growth at 24 hours is likely through cell cycle modulation rather than apoptosis.