Malyngolide Dimer, a Bioactive Symmetric Cyclodepside from the Panamanian Marine Cyanobacterium Lyngbya majuscula

Fractionation of the extract of the marine cyanobacterium Lyngbya majuscula collected from Panama led to the isolation of malyngolide dimer (1). The planar structure of 1 was determined using ID and 2D NMR spectroscopy and HRESI-TOFMS. The absolute configuration was established by chemical degradation followed by chiral GC-MS analyses and comparisons with an authentic sample of malyngolide seco-acid (4). Compound 1 showed moderate in vitro antimalarial activity against chloroquine-resistant Plasmodium falciparum (W2) (IC50 = 19 mu M) but roughly equivalent toxicity against H-460 human lung cell lines. Furthermore, because the closely related cyanobacterial natural product tanikolide dirtier (5) was a potent SIRT2 inhibitor, compound 1 was evaluated in this assay but found to be essentially inactive.