Fig. 5From: Bioactive isopimarane and 3,4-seco isopimarane diterpenoids from Isodon amethystoidesGrowth inhibitory effects of compound 4 on Hela and A549 cancer cells. The in vitro dose–response was evaluated in the cells at seven twofold serial dilution concentrations with 3 independent experiments. The IC50 values were determined by fitting dose–response curves with the equation log (inhibitor) vs. normalized response–variable slope to the data by using GraphPad Prism softwareBack to article page