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. The biological activities of the isolated metabolites, in particular their antimicrobial properties, were investigated in a series of assay systems.
Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk Str. 1, Bonn 53121, Germany. tgulder@uni-bonn.de
Tobias A M
TA
Gulder
Hanna
H
Hong
Jhonny
J
Correa
Ekaterina
E
Egereva
Jutta
J
Wiese
Johannes F
JF
Imhoff
Harald
H
Gross
D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D059001:Aquatic Organisms / Q000378:metabolism*; D002140:California; D005658:Fungi / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D013237:Stereoisomerism
D000890:Anti-Infective Agents; D010456:Peptides, Cyclic; C580989:lajollamide A