As a continuation of our previously demonstrated potential of 11-epi-fistularin (1) to bind DNMT1 and reduce its activity [28], and that of isofistularin-3 extracted from the sponge Aplysina aerophoba, and its ability to inhibit DNMT1 leading to DNA demethylation in leukemia cells [49], we also investigated the capacity of our compounds 2, 3, 13, and 14 to modulate the activity of DNMT1 (Figure 10). This evidence concerns the gene DNMT1 and leukemia.