Haliclamide, a novel cyclic metabolite from the Vanuatu marine sponge Haliclona sp.

A new cyclic metabolite, named haliclamide (1), has been isolated from the Vanuatu marine sponge Haliclona sp. Its structure was determined from 1D and 2D NMR studies and mass spectral data. Haliclamide (1) represents a new 16-membered cyclic depsipeptide containing, along with a N-methylphenylalanine, two residues never isolated from natural sources: 5-hydroxy-octanoic acid (HOA) and 6-amino-7-hydroxy-2-methylheptanoic acid (AHMA). Haliclamide (1) exhibited cytotoxicity against the NSCLC-N6 human bronchopulmonary non-small-cell-lung carcinoma cell lines with an IC50 value of 4.0 μg/mL.