Microspinosamide, a new HIV-inhibitory cyclic depsipeptide from the marinesponge Sidonops microspinosa

Microspinosamide (1), a new cyclic depsipeptide incorporating 13 amino acid residues, was isolated from extracts of an Indonesian collection of the ma rine sponge Sidonops microspinosa. Its structure was elucidated by extensiv e NMR and mass spectral analyses, and by chemical degradation and derivatiz ation studies. The tridecapeptide 1 incorporates numerous uncommon amino ac ids, and it is the first naturally occurring peptide to contain a beta -hyd roxy-p-bromophenylalanine residue. Microspinosamide (1) inhibited the cytop athic effect of HIV-1 infection in an XTT-based in vitro assay with an EC50 value of approximately 0.2 mug/mL.