Metabolome consistency: additional parazoanthines from the mediterranean zoanthid parazoanthus axinellae.

Ultra-high pressure liquid chromatography coupled to high resolution mass spectrometry (UHPLC-MS/MS) analysis of the organic extract obtained from the Mediterranean zoanthid Parazoanthus axinellae yielded to the identification of five new parazoanthines F-J. The structures were fully determined by comparison of fragmentation patterns with those of previously isolated parazoathines and MS/MS spectra simulation of in silico predicted compounds according to the metabolome consistency. The absolute configuration of the new compounds has been assigned using on-line electronic circular dichroism (UHPLC-ECD). We thus demonstrated the potential of highly sensitive hyphenated techniques to characterize the structures of a whole family of natural products within the metabolome of a marine species. Minor compounds can be characterized using these techniques thus avoiding long isolation processes that may alter the structure of the natural products. These results are also of interest to identify putative bioactive compounds present at low concentration in a complex mixture.

Revising the absolute configurations of coatlines via density functional theory calculations of electronic circular dichroism spectra.

Coatline A (1) and α-epi-coatline A (4) co-occur in the trunk extract of Andira coriacea. Inspection of their chiroptical properties led to intriguing results. After a careful examination of the experimental data used for the previously reported absolute configuration of these compounds, some uncertainties were identified. A combined theoretical approach including conformational analyses and calculation of electronic circular dichroism (ECD) spectra, in addition with experimental data obtained for schoepfin A (5) and the new schoepfin D (6) isolated from Senna quinquangulata, allowed the revision of the absolute configuration of coatlines A (1) and B (2).

New insight into marine alkaloid metabolic pathways: revisiting oroidin biosynthesis.

Sponge natural product biosynthesis: A highly sensitive in vivo protocol based on (14)C radiolabeled precursors and beta-imager autoradiography allowed the unraveling of the origin of the pyrrole 2-aminoimidazole-containing key biosynthetic intermediate oroidin. Proline and lysine are now proposed as the early precursors of the pyrrole and the 2-aminoimidazole moieties of oroidin respectively.