Isolation, structure elucidation and total synthesis of lajollamide A from the marine fungus Asteromyces cruciatus.

The marine-derived filamentous fungus Asteromyces cruciatus 763, obtained off the coast of La Jolla, San Diego, USA, yielded the new pentapeptide lajollamide A (1), along with the known compounds regiolone (2), hyalodendrin (3), gliovictin (4), ¹N-norgliovicitin (5), and bis-N-norgliovictin (6). The planar structure of lajollamide A (1) was determined by Nuclear Magnetic Resonance (NMR) spectroscopy in combination with mass spectrometry. The absolute configuration of lajollamide A (1) was unambiguously solved by total synthesis which provided three additional diastereomers of 1 and also revealed that an unexpected acid-mediated partial racemization (2:1) of the L-leucine and L-N-Me-leucine residues occurred during the chemical degradation process.

Antimalarial linear lipopeptides from a Panamanian strain of the marine cyanobacterium Lyngbya majuscula.

As part of the Panama International Cooperative Biodiversity Groups (ICBG) project, two new (2, 4) and two known (1, 3) linear alkynoic lipopeptides have been isolated from a Panamanian strain of the marine cyanobacterium Lyngbya majuscula. Carmabin A (1), dragomabin (2), and dragonamide A (3) showed good antimalarial activity (IC50 4.3, 6.

Minor alkaloids from Guatteria dumetorum with antileishmanial activity.

Nine known alkaloids [(+)-isodomesticine (1), (+)-norisodomesticine (2), (+)-nantenine ( 3), (+)-neolitsine (4), (+)-lirioferine (5), (+)-N-methyllaurotetanine (6), (+)-norlirioferine (7), (+)-isoboldine (8) and (+)-reticuline (9)] were isolated from young leaves of Guatteria dumetorum. Their structures were confirmed by NMR, mass and UV spectral analysis and by comparison to literature data. The growth inhibitory activity of each alkaloid was determined against the parasite Leishmania mexicana.