Homophymamide A, Heterodetic Cyclic Tetrapeptide from a sp. Marine Sponge: A Cautionary Note on Configurational Assignment of Peptides That Contain a Ureido Linkage.

A previously unreported heterodetic cyclic peptide, homophymamide A (), was isolated from a sp. marine sponge. The structure of homophymamide A was determined to be a lower homologue of anabaenopeptins by spectroscopic analysis, chemical degradation, and chemical synthesis.

Metachromins X and Y from a marine sponge Spongia sp. and their effects on cell cycle progression.

New sesquiterpene quinones, metachromins X (1) and Y (2), together with the known metachromins C (3), J (4), and T (5), were isolated as inhibitors of cell cycle progression in the HeLa/Fucci2 cells. The structure of 1 was assigned by spectroscopic data and confirmed by a total synthesis. The planar structure of 2 was determined by interpretation of spectroscopic data, whereas its absolute configuration was analyzed by a combination of chiral HPLC and CD spectroscopy.

Isolation and identification of -isopentenyladenosine as the cytotoxic constituent of a marine sponge sp.

-Isopentenyladenosine (iA) was isolated from a marine sponge sp. as the major cytotoxic constituent along with -isopentenyladenosine 5'-monophosphate (iAP) which was inactive. The structures of iA and iAP were assigned by a combination of the analysis of NMR spectroscopy and mass spectrometry.