Isolation and Structure Determination of Akunolides, Macrolide Glycosides from a Marine Okeania sp. Cyanobacterium.

Akunolides A ( 1 ), B ( 2 ), C ( 3 ), and D ( 4 ), new macrolide glycosides, were isolated from a marine Okeania sp. cyanobacterium. Their structures were elucidated by spectroscopic analyses and derivatization reactions. Akunolides A-D ( 1 - 4 ) are classified as 16-membered macrolide glycosides, which are relatively rare structures for marine cyanobacterium-derived natural products. Akunolides A-D ( 1 - 4 ) showed moderate antitrypanosomal activities against Trypanosoma brucei rhodesiense , with IC 50 values ranging from 11 to 14 μM. Furthermore, akunolides A ( 1 ) and C ( 3 ) exhibited no cytotoxicity against normal human WI-38 cells even at a concentration of 150 μM.