New antimalarial fusarochromanone analogs produced by the fungal strain Fusarium sp. FKI-9521

Two new antimalarial compounds, named deacetyl fusarochromene ( 1 ) and 4′- O -acetyl fusarochromanone ( 2 ), were discovered from the static fungal cultured material of Fusarium sp. FKI-9521 isolated from feces of a stick insect ( Ramulus mikado ) together with three known compounds fusarochromanone ( 3 ), 3′- N -acetyl fusarochromanone ( 4 ), and 5 (fusarochromene or banchromene). The structures of 1 and 2 were elucidated as new analogs of 3 by MS and NMR analyses. The absolute configurations of 1 , 2 , and 4 were determined by chemical derivatization. All five compounds showed moderate in vitro antimalarial activity against chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains, with IC 50 values ranging from 0.08 to 6.35 µM.