Effect of the 8 best inhibitors in sensitizing H1299 cells to cisplatin-induced cytotoxicity. The MTS assays was performed as a measure of cell viability and all the compounds (CB9-G, CB20-20, CB22-G, CB23-G, CB41-G, CB49-G at 50 µM; CB46-G at 25 µM; CB60-G at 10 µM) were applied to the cells in combination with cisplatin (1 µM) for 72 h. Values represent mean ± SD and are expressed as percentages of the solvent-treated control cells considered as 100% of cell viability, identified as the dotted line in the graphs (n = 3–5). * p < 0.05, ** p < 0.01, *** p < 0.001, and **** p < 0.0001 (one-way ANOVA, Tukey’s multiple comparisons test).