Fig. 3.
Effect of Vernopicrin (1) and Vernomelitensin (2) pretreatment on colony formation of PC-3 cell line in vitro was studied. PC-3 cells (75 cells/well) were treated with 50 nM, 500 nM, 5 mM, 50 mM and 0.25% DMSO control in quadruplet. The assay was terminated on day 9 by removing the media; adding 0.5 mL methanol for 15 min (− 20 °C); removing methanol and then adding 0.25% crystal violet for less than 30 s. Plates were rinsed with water and allowed to dry. Colonies were counted under a microscope and data analyzed to obtain mean ± SEM in Graphpad Prism Software. Both compounds show potent colony growth inhibition activity at 500 nM suggesting an IC50 < 500 nM.