Cytotoxicity of Libyan Juniperus phoenicea against Human Cancer Cell Lines A549, EJ138, Hepg2 and MCF7

Background: The current study was undertaken to assess the cytotoxicity of the leaves of Libyan Juniperus phoenicea (Cupressaceae) against human cancer cell lines. Methods: The cytotoxicity of the n-hexane, dichloromethane (DCM) and methanol (MeOH) extracts of the leaves of J. phoenicea (JP), obtained from sequential Soxhlet extractions, was assessed against four human cancer cell lines: EJ138 (human bladder carcinoma), HepG2 (human liver hepatocellular carcinoma), A549 (human lung carcinoma) and MCF7 (human breast adenocarcinoma) using the MTT assay. Results: The cell line A549 was the most sensitive to the JP extracts, with the highest level of cytotoxicity with the IC50 values of 16, 13 and 100 µg/mL for the DCM, n-hexane and MeOH extracts, respectively. However, generally the most potent cytotoxic extract across the other cells tested was the n-hexane extract, followed by the DCM extract, whilst the MeOH extracts showed little or no cytotoxicity. The percentage of viability of cells decreased as the concentration of test compounds increased. The cytotoxicity of various chromatographic fractions from the extracts was also studied against the A459 cells. For the n-hexane fractions, the IC50 values were 160, 62, 90, 30, 9.5 and 40 µg/mL for fractions 1 to 5 and 7, respectively. Fractions 4 and 5 showed the greatest effect. DCM fractions 2, 3 and 4 had the IC50 values of 60, 92 and 19 µg/mL, respectively, and DCM fractions 5 to 8 were non-cytotoxic. Fractions 1 and 2 of the MeOH extract were non-cytotoxic, whereas cytotoxicity was observed for fractions 3 and 4 with IC50 values of 50 and 85 µg/mL, respectively. Conclusion: The outcome of the present study suggested that the JP leaves possess cytotoxic activities. The high level of cytotoxicity of the n-hexane and DCM extracts suggested that lipophilicity might affect the cytotoxicity of JP, where the less polar compounds had the strongest cytotoxicity.