Determination of Cytotoxic Activities

As reported recently in the literatures, rocaglates exert significant cytotoxic activities^{24,25,26,27,28}. In this investigation, the IC₅₀ values in human leukemic (HL-60), colon cancer (HT-29), human breast cancer (MCF-7), and human liver hepatocellular carcinoma (HepG2) cell lines were determined to evaluate the cytotoxicity of the isolated compounds. The isolated compounds were evaluated based on their cytotoxic activities against the above-mentioned tumor cell lines. The silvestrol analogues exhibited more potent cytotoxic activity than the cyclopenta[bc]benzopyrans, as shown in Table 4. The cytotoxicity assay used in this study is based on the MTT method and was performed in 96-well microplates³⁶. The cells were cultured in DMEM medium (Hyclone, Logan, UT, USA) with 10% foetal bovine serum in an atmosphere with 5% CO₂ at 37 °C prior to the assay. Then, 150 μL of the cell suspension was seeded into each well of 96-well the cell culture plates, and the cells were allowed to adhere for 12 h before testing. The initial density of the cells was 10⁵/mL. Each tumor cell line was exposed to each test compound at concentrations of 0.001, 0.01, 0.1, 1, and 10 μM in triplicate for 48 h, and paclitaxel and cis-platinum were used as positive controls. Using the Reed-Muench method, the IC₅₀ values were calculated based on the obatained cell viability³⁷.