ABSTRACT:

Purpose: To investigate the most effective compound of C. ambrosioides essential oil for the induction of cell death in human breast cancer cells (MCF-7), and the mechanism of induction. Methods: MCF-7 cells were treated with essential oil and its two main components, 1-isopropyl-4- methylbenzene and α-terpinene, respectively, for 24 and 48 h in vitro. To determine their cytotoxicity on MCF-7 cells, in vitro cytotoxicity, 3-(4, 5-dimethylthaizol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and live/dead cell fluorescent staining were used. MCF-7 cellular superoxide dismutase (SOD), catalase (CAT) vitality and malondialdehyde (MDA) content were also evaluated. Results: MTT results showed that essential oil and its two main compositions significantly inhibited the growth of MCF-7 cells in 24 h (p < 0.05), which was consistent with the Live/dead cell fluorescent staining results. After 24 h incubation the average inhibition rate is 58.98 % for essential oil, 37.8 % for 1-isopropyl-4-methylbenzene and 32.09 % for α-terpinene. With increase in the concentration of essential oil and the two main components, the relative activity of SOD significantly decreased (p < 0.05), while the relative activity of CAT was gradually increased (p < 0.05), compared with control. MDA relative content significantly increased (p < 0.05) until the concentration was 1.25, 0.21 and 0.17 μg/ml for essential oil , 1-isopropyl-4-methylbenzene and α-terpinene , and thereafter significant