Hupercumines A and B, <i>Lycopodium</i> Alkaloids from <i>Huperzia cunninghamioides</i>, Inhibiting Acetylcholinesterase

A novel class of C₃₈N₄ <i>Lycopodium</i> alkaloid, hupercumine A (<b>1</b>), consisting of two octahydroquinolines, a decahydroquinoline, and a piperidine, and a new C₂₇N₃-type alkaloid, hupercumine B (<b>2</b>), were isolated from <i>Huperzia cunninghamioides</i> (Hayata) Holub. The structures and absolute configurations of <b>1</b> and <b>2</b> were elucidated on the basis of spectroscopic data, chemical means, and biogenetic point of view. Hupercumines A (<b>1</b>) and B (<b>2</b>) showed moderate inhibitory activity against acetylcholinesterase

Cycloforskamide, a Cytotoxic Macrocyclic Peptide from the Sea Slug <i>Pleurobranchus forskalii</i>

A macrocylic dodecapeptide, cycloforskamide, was isolated from the sea slug <i>Pleurobranchus forskalii</i>, collected off Ishigaki Island, Japan. Its planar structure was deduced by extensive NMR analyses and was further confirmed by MS/MS fragmentation analyses. Finally, the absolute configuration was determined by total hydrolysis and chiral-phase gas chromatographic analysis. This novel dodecapeptide contains three d-amino acids and three thiazoline heterocycles and exhibits cytotoxicity against murine leukemia P388 cells, with an IC₅₀ of 5.8 μM