Aspergillicins A–E: five novel depsipeptides from the marine-derived fungus Aspergillus carneus

Abstract

A search for new antiparasitic agents from a strain of the fungus Aspergillus carneus isolated from an estuarine sediment collected in Tasmania, Australia, yielded the known terrestrial fungal metabolite marcfortine A (1) as an exceptionally potent antiparasitic agent. This study also yielded a series of new depsipeptides, aspergillicins A-E (2-6) and the known terrestrial fungal metabolite acyl aszonalenin (7). Marcfortine A (1) and acyl aszonalenin (7) were identified by spectroscopic analysis, with comparison to literature data. Complete stereostructures were assigned to aspergillicins A-E (2-6) on the basis of detailed spectroscopic analysis, together with ESIMS analysis of the free amino acids generated by acid hydrolysis, and HPLC analysis of Marfey derivatives prepared from the acid hydrolysate. The peptide amino acid sequence for all aspergillicins was unambiguously assigned by MS(n) ion-trap ESI mass spectrometry.

Use of Marfey's reagent and analogs for chiral amino acid analysis: Assessment and applications to natural products and biological systems

“…A ternary gradient composed of water (A), MeOH (B), and MeCN-1% formic acid (C) was used at column temperature of 50 • C and effluents applied to ESI-MS. This method was named new 'C 3 Marfey's method' for AA analysis by the authors [40,41] and is currently subject of further refinements. Table 2 Percentage ratio of meso-and ll-A2pm stereoisomers in the colony hydrolysates of standard actinomycetes [39].…”

“…l-Ile, l-allo-Ile and d-Ile, d-allo-Ile) the group of Capon [40] used MR for derivatization and replaced the commonly used C 18 stationary phase by a C 3 stationary phase (5 m particle size, 150 × 4.6 mm column). A ternary gradient composed of water (A), MeOH (B), and MeCN-1% formic acid (C) was used at column temperature of 50 • C and effluents applied to ESI-MS.…”

“…Using MR the presence of d-Phe and l-Pro could be established in components A and B whereas in C and D replacement of the d-Phe residue with an Ile and Val residue was determined. Using the same mobile phase and the column as reported earlier to describe 'C 3 Marfey's method' [40], Capon et al [41] reported that the diastereomers formed with l-and d-Pro are baseline resolved from an interfering residual reagent peak of MR [41]; it was an additional benefit.…”

Acetylaszonalenin Biosynthesis in Neosartorya fischeri

“…Together with its non-acetylated form aszonalenin, it was also identified in various fungal strains, e.g. Aspergillus zonatus (4), Aspergillus fumigatus (5), Aspergillus carneus (6), and Neosartorya fischeri IFM52672 (7). Their stereoisomer epiaszonalenins A ( Fig.…”

Roquefortine C and Related Prenylated Indole Alkaloids

“…6.1 and 6.4 ). Aszonalenin and its acetylated derivative acetylaszonalenin are produced by Aspergillus zonatus [ 57 ], A. fumigatus [ 58 ], A. carneus [ 59 ], and N. fi scheri NRRL 181 [ 60 ].…”