New naphthoquinones and a new δ-lactone produced by endophytic fungi from Costa Rica

While searching for compounds with antimalarial activity, two new naphthoquinones, delitzchianones A (1) and B (2), were separated from Delitzchia winteri, an endophytic fungus from Costa Rica. The same search also led to a new 8-acetoxy pestalopyrone (3) and the known compound, pestalopyrone (4) from another Costa Rican endophytic fungus, Phomatospora bellaminuta. The structures of the three new compounds 1, 2, and 3 were established with extensive NMR and MS analyses. All four compounds were tested for activity in a growth/no growth Dd2 assay but only compound 4 had measurable activity with an IC50 value of 37 μM.