Cytotoxicity Evaluation of Essential Oil and its Component from Zingiber officinale Roscoe

Zingiber officinale Roscoe has been widely used as a folk medicine to treat various diseases, including cancer. This study aims to re-examine the therapeutic potential of co-administration of natural products and cancer chemotherapeutics. Candidate material for this project, α-zingiberene, was extracted from Zingiber officinale Roscoe, and α-zingiberene makes up 35.02 ± 0.30% of its total essential oil. α-Zingiberene showed low IC50 values, 60.6 ± 3.6, 46.2 ± 0.6, 172.0 ± 6.6, 80.3 ± 6.6 (μg/mL) in HeLa, SiHa, MCF-7 and HL-60 cells each. These values are a little bit higher than IC50 values of general essential oil in those cells. The treatment of α-zingiberene produced nucleosomal DNA fragmentation in SiHa cells, and the percentage of sub-diploid cells increased in a concentration-dependent manner in SiHa cells, hallmark features of apoptosis. Mitochondrial cytochrome c activation and an in vitro caspase-3 activity assay demonstrated that the activation of caspases accompanies the apoptotic effect of α-zingiberene, which mediates cell death. These results suggest that the apoptotic effect of α-zingiberene on SiHa cells may converge caspase-3 activation through the release of mitochondrial cytochrome c into cytoplasm. It is considered that anti-proliferative effect of α-zingiberene is a result of apoptotic effects, and α-zingiberene is worth furthermore study to develop it as cancer chemotherapeutics.