Palmerolide A, a Cytotoxic Macrolide from the Antarctic Tunicate Synoicum adareanum

Palmerolide A, a 20-membered macrocyclic polyketide bearing carbamate and vinyl amide functionality, was isolated from the tunicate Synoicum adareanum collected from the vicinity of Palmer Station on the Antarctic Peninsula. Palmerolide A displays potent and selective cytotoxicity toward melanoma (UACC-66 LC50 = 0.018 muM) and appears to operate via inhibition (IC50 = 2 nM) of V-ATPase.