Callyaerin g, a new cytotoxic cyclic peptide from the marine sponge callyspongia aerizusa

From the ethyl acetate fraction of the Indonesian sponge Callyspongia aerizusa extract, a new cyclic peptide named callyaerin G was isolated. Its structure was elucidated by extensive 1D and 2D NMR (1H NMR, TOCSY and ROESY) studies and mass spectrometric data (ESI- and FAB-MS). The stereochemistry was determined by Marfey's analysis. Callyaerin G was found to exhibit cytotoxic activity when tested against different cancer cell lines