Cytotoxicity screening of essential oils in cancer cell lines

Abstract

This study evaluated the cytotoxicity activity of the essential oils of Tagetes erecta L., Asteraceae (TE-OE), Tetradenia riparia (Hochst.) Codd, Lamiaceae (TR-OE), Bidens sulphurea (Cav.) Sch. Bip., Asteraceae(BS-OE), and Foeniculum vulgare Mill., Apiaceae (FV-OE), traditionally used in folk medicine, againstthe tumor cell lines murine melanoma (B16F10), human colon carcinoma (HT29), human breast ade-nocarcinoma (MCF-7), human cervical adenocarcinoma (HeLa), human hepatocellular liver carcinoma(HepG2), and human glioblastoma (MO59J, U343, and U251). Normal hamster lung fibroblasts (V79cells) were included as control. The cells were treated with essential oil concentrations ranging from3.12 to 400 μg/ml for 24 h. The cytotoxic activity was evaluated using the XTT assay; results wereexpressed as IC50, and the selectivity index was calculated. The results were compared with thoseachieved for classic chemotherapeutic agents. TE-OE was the most promising among the evaluated oils:it afforded the lowest IC50values for B16F10 cells (7.47 ± 1.08 μg/ml) and HT29 cells (6.93 ± 0.77 μg/ml),as well as selectivity indices of 2.61 and 2.81, respectively. The major BS-EO, FV-EO and TE-EO chemi-cal constituents were identified by gas chromatography mass spectrometry as being (E)-caryophyllene(10.5%), germacrene D (35.0%) and 2,6-di-tert-butyl-4-methylphenol (43.0%) (BS-EO); limonene (21.3%)and (E)-anethole (70.2%) (FV-EO); limonene (10.4%), dihydrotagetone (11.8%), α-terpinolene (18.1%) and(E)-ocimenone (13.0%) (TE-EO); and fenchone (6.1%), dronabinol (11.0%), aromadendrene oxide (14.7%)and (E,E)–farnesol (15.0%) (TR-EO). 2,6-di-tert-butyl-4-methylphenol (43.0%), (E)-anethole (70.2%) and α-terpinolene (18.1%), respectively. These results suggest that TE-OE may be used to treat cancer withoutaffecting normal cells.