PU139 is a potent inhibitor of pan-histone acetyltransferase (HAT) that blocks Gcn5, PCAF, CBP, and p300 with IC50 values of 8.39 μM, 9.74 μM, 2.49 μM, and 5.35 μM, respectively. It significantly impairs Smp14 promoter activity, suggesting that targeting SmGCN5 and SmCBP1 is a novel strategy to control S. mansoni egg development, it also exhibits anticancer activity.