Figure 4.
Effect of EVOO-PEs derived from three different cultivars (Žižolera, Bjelica, and Crnica) on cellular metabolic activity after pre-treatment with DTIC. Cells were pre-treated with various concentrations of DTIC (100, 200, 600, or 1000 µM) for 6 h and afterwards exposed for 24 h to EVOO-PEs in concentrations corresponding to the IC60 values for (a) the A375 melanoma cell line and (b) the A375M metastatic melanoma cell line. In both cases, comparative non-cancerous HaCaT cells were exposed to the same concentrations of EVOO-PEs as applied to A375 and A375M cells. Metabolic activity was measured using an MTS assay. The results of the six experiments are expressed as mean percentage of cell viability compared to non-treated cells ± SD. Statistically significant differences (p < 0.05) are marked as follows: black asterisk—compared to the non-treated cells; blue asterisk—compared to the cells pre-treated with DTIC; red asterisk—difference between melanoma and HaCaT cells. Legends: pDTIC—pre-treatment with DTIC; pDTIC + Ž, pDTIC + B, pDTIC + C—pre-treatment with DTIC followed by exposure to EVOO-PEs derived from three different cultivars, Žižolera, Bjelica, and Crnica, respectively.