Fig 1: Cytotoxic (A) and cytostatic (B) effects of PP compounds. (A) Human glioblastoma cells, LN-229 (ATCC CRL-2611), were cultured in six-well plates at 2×105 /well in DMEM containing 10% FBS. The percentage of cell death (A-F) and the total cell number (B-F) were calculated at time 0 (T0; 6 hours after plating; plating efficiency) and at 24, 48, 72, and 96 hours after treatments. The cells were treated with FF at 10, 25, and 50 μM (FF/10, FF/25, and FF/50) and with PP1, PP2, PP3, and PP4 at 5, 10, 25, and 50 μM. Control cultures were treated with corresponding volumes of DMSO, which was used as a solvent for both FF and PP compounds. At the end point of each experiment, the cells were harvested in a quantitative manner, treated with 0.4% trypan blue solution (Sigma), and counted using bright field hemocytometer. Data represent average values from three independent experiments in triplicate (n = 9) ± SD. * indicates PP1 or PP2 or PP3 or PP4 values significantly different from the corresponding time point values for DMSO treatment. In B-F, both trypan blue–positive and trypan blue–negative cells were included in the calculation of cell number, and % cell death is indicated at the bottom of the corresponding column. Data represent average values ± SD (n = 3). * indicates PP1 or PP2 or PP3 or PP4 values significantly different from the DMSO value at 96 hours.