TEN NOVEL METABOLITES FROM MARINE TUNICATE DIDEMNUM MOLLE

The tunicate Didemnum molle is known for producing cytotoxic hexa- and heptacyclic peptides that are characterized by alternating sequence of thiazole or thiazoline rings and hydrophobic amino acids. In the course of our ongoing research to discover potential biomedicines from marine invertebrates, we examined a sample of the tunicate D. molle collected in Madagascar. The crude extract was separated on Sephadex LH-20 columns and the semi-pure compounds were separated on reversed phase HPLC columns to afford ten novel metabolites. Two heptacyclic peptides Mayotamide C and D, eight phenylethylamine derivatives related in structure to Molleurea A that was found to inhibit the HIV virus in a cytoprotective cell based assay, along with the known compounds Mayotamide A and B. The structure of the novel compounds was elucidated by analysis of their 2D-NMR spectra, HR MS and key fragmentations in the MS/MS spectra. The structure elucidation and biological activities of the new compounds will be presented.