Antimalarial halorosellinic acid from the marine fungus Halorosellinia oceanica

Three known compounds, 2-hexylidene-3-methylsuccinic acid (1), cytochalasin Q (2), and 5-carboxymellein (3), together with two new derivatives, 2-hexy lidene-3-methylsuccinic acid 4-methyl ester (4) and an ophiobolane sesterte rpene named halorosellinic acid (5), were isolated from culture broth of th e marine fungus Halarosellinia oceanica BCC 5149. Compounds 1-3 exhibited m oderate cytotoxicity against KB and BC-1 cell lines with IC50 values of 1-1 3 mug/mL, while compounds 2, 3, 5. and 6 showed antimalarial activity with respective IC50 values of 17, 4, 13, and 19 mug/mL. Halorosellinic acid (5) possessed only weak antimycobacterial activity with the minimum inhibitory concentration of 200 mug/mL. (C) 2001 Elsevier Science Ltd. All rights res erved.