Inhibition of Colorectal Cancer Cell Line CaCo-2 by Essential Oil of Eucalyptus camaldulensis Through Induction of Apoptosis

Treatment of human cancer diseases is one of the challenges in drug development due to the increase of resistances to chemotherapeutic drugs. Isolation of natural products from medicinal plants and other organisms often led to novel drugs, which could important for the treatment of diseases such as colorectal cancer. The aim of this study was to investigate antioxidant and anticancer activity of Eucalyptus camaldulensis essential oil on colorectal cancer cell line Caco-2. The antioxidant activity of extracted E. camaldulensis essential oil (1000, 800, 400, 200, 100, 50, 25, 12.5, 6 and 3 μg/mL) was evaluated by free radicals inactivation method. Moreover, MTT assay was used to examine the cytotoxic effects of E. camaldulensis essential oil on Caco-2 cell line. The mRNA expression of BAX and BCL-2 genes was studied using quantitative Real-Time PCR method, in treated cancer cells compared to untreated cells. We indicated a significant impressive antioxidant activity in 1000 μg/mL of E. camaldulensis essential oil, in a concentration-dependent manner. In addition, we found that this product exerted cytotoxic effect on cancer cells when 100 μg/mL concentration was considered as half maximal inhibitory concentration (IC50). Also, expression of BAX and BCL-2 genes was significantly up-regulated and downregulated, respectively, in the treated Caco-2 cells with E. camaldulensis essential oil. In conclusion, our study showed a significantly antioxidant and anticancer activity in E. camaldulensis essential oil in a concentration and time dependent manner, which may be due to reduction of free radicals and induction of apoptosis process in colorectal cancer cells.