Oxepinamides A-C and Fumiquinazolines H-I: Bioactive Metabolites from a Marine Isolate of a Fungus of the GenusAcremonium

Belofsky, Gilbert N.; Anguera, Montserrat C.; Jensen, Paul R.; Fenical, William; Köck, Matthias

doi:10.1002/(sici)1521-3765(20000417)6:8<1355::aid-chem1355>3.0.co;2-s

Cited by 102 publications

(81 citation statements)

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“…obtained from the surface of a Caribbean tunicate. 16 More specifically, the NMR data for 1 were indicative of a nor analogue of the known fumiquinazoline D, in which the C-3 tertiary methyl (δ H 2.02, s) was replaced by a C-3 methine proton (δ H 5.24, d) showing coupling to the 2-NH (δ H 9.06, d). This nor-methyl fumiquinazoline structure represents a new carbon skeleton.…”

Section: Resultsmentioning

confidence: 99%

Cottoquinazoline A and Cotteslosins A and B, Metabolites from an Australian Marine-Derived Strain of Aspergillus versicolor

et al. 2009

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An Australian marine-derived isolate of Aspergillus versicolor (MST-MF495) yielded the known fungal metabolites sterigmatocystin, violaceol I, violaceol II, diorcinol, (-)-cyclopenol, and viridicatol, along with a new alkaloid, cottoquinazoline A (1), and two new cyclopentapeptides, cotteslosins A (2) and B (3). Structures for 1-3 and the known compounds were determined by spectroscopic analysis. The absolute configurations of 1-3 were addressed by chemical degradation and application of the C(3) Marfey's method. The use of "cellophane raft" high-nutrient media as a device for up-regulating secondary metabolite diversity in marine-derived fungi is discussed. The antibacterial properties displayed by A. versicolor (MST-MF495) were attributed to the phenols violaceol I, violaceol II, and diorcinol, while cotteslosins 2 and 3 were identified as weak cytotoxic agents.

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Section: Resultsmentioning

confidence: 99%

Cottoquinazoline A and Cotteslosins A and B, Metabolites from an Australian Marine-Derived Strain of Aspergillus versicolor

et al. 2009

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“…Unexpectedly, a minimum set of four amide bond rotamers could be observed for 2, while two (one major, one minor) rotational isomers could be observed for 1. The differing circumstances can be seen by comparing the intense and small doublets in the ratio 85: 15 Data from a variable-temperature 1 H NMR (VT NMR) experiment was sought to further define the presence of the rotamers discussed above for 1 and 2. The latter was chosen for this analysis because it contained several well-resolved proton signals.…”

Section: Resultsmentioning

confidence: 99%

“…Only five previous studies had examined the chemistry of marine-derived strains of Acremonium, resulting in different biosynthetic products isolated from distinct sources. This interesting pattern included reports of (a) polyketides 12 and hydroquinones 13 from algal-derived cultures, (b) ketide-terpenes from a strain isolated from submerged wood, 14 (c) two families of alkaloids from a tunicate-derived fungus, 15 and (d) diterpene glycosides from a holothurin source. 16 In contrast to these outcomes, our initial NMR spectra of the crude extracts from the sponge-derived Acremonium culture displayed signals characteristic of polypeptides.…”

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confidence: 99%

Highly N-Methylated Linear Peptides Produced by an Atypical Sponge-Derived Acremonium sp.

et al. 2006

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RHM1(1) and RHM2 (2) are highly N-methylated linear octapeptides produced by an atypical strain of Acremonium sp., cultured from a marine sponge collected in Papua New Guinea. The known peptaibiotic efrapeptin G (3) was also isolated from this fungus. The planar structures of 1 and 2 were assigned based on 1D-and 2D-NMR experiments and fragmentation patterns from ESIMS. The absolute configuration of 1 was determined via Marfey's method; the absolute configuration of 2 is proposed to be identical. Efrapeptin G (3) displayed potent cytotoxicity against murine cancer cell lines, while RHM1 (1) and RHM2 (2) showed weak cytotoxicity against murine cancer cell lines; efrapeptin G (3) and RHM1 (1) also demonstrated antibacterial activity.It is not currently possible to predict the chemical signatures of filamentous fungi isolated from marine sources. 1 Low molecular weight (<500 amu) bioactive polyketides often dominate the secondary metabolites isolated from terrestrial fungal cultures. Two important therapeutically active compounds produced by well-studied fungal genera Penicillium and Aspergillus illustrate this chemistry. Mycophenolic acid (C 17 H 20 O 6 ), discovered over 70 years ago from Penicillium sp., 2 is an immunosuppressive agent (1995: mycophenolate mofetil, first marketed in the U.S.) that has also shown promising antiviral properties. 3 The members of the well-defined structural class headed by mevinolin (C 24 H 36 O 5 ), originally isolated from Aspergillus, are potent HMG-CoA inhibitors of cholesterol biosynthesis (1987: first FDA approval of lovastatin). 4 Exploration of structural diversity of marine-derived fungal natural products has been in progress for more than a decade. Early discoveries of the chloriolins 5 and the fumiquinazolines 6 validated the hypothesis that marine-derived strains of fungi could serve as useful sources of unprecedented molecular frameworks. Compounds such as asperazine 7 from the sponge-derived, chemically rich Aspergillus niger, or the aigilomycins 8 from a mangrove isolate of Aigialus parVus, provided further validation that new chemotypes could be discovered from genera previously isolated from terrestrial sources. Similarly, the outstanding cytotoxic properties of the gymnastatins from Gymnascella 9 as well as the © 2006 American Chemical Society and American Society of Pharmacognosy * To whom correspondence should be addressed. Tel: 831-459-2603. Fax: 831-459-2935. phil@chemistry.ucsc.edu.. Supporting Information Available: 1 H and 13 C NMR and FABMS for compound 3, and 1 H, 13 C NMR, gHMBC, gCOSY, and TOCSY for compounds 1 and 2 along with VT NMR figures are available free of charge via the Internet at http://pubs.acs.org. This work describes the constituents of a marine sponge-derived Acremonium strain grown in saltwater culture. At the outset we recognized numerous previous studies on terrestrial members of this genus, with the antibiotic cephalosporin C 11 as the most notable metabolite produced. Only five previous studies had examined the chemistry o...

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“…For haemoventosin (6.14), using the reported COSY and HMBC correlations, 53 as well as the five fixed bonds, shown in bold, COCON generated 938 possible structures. After introducing 1,1-ADEQUATE correlations, 206 possible structures were generated.…”

Section: 14mentioning

confidence: 99%

CASE 2D NMR-based Expert Systems

2011

Contemporary Computer-Assisted Approaches to Molecular Structure Elucidation

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Modern expert systems utilize 1D and 2D NMR data. The 2D NMR expert systems described in the literature over the last two decades will be reviewed as these form the foundation of understanding from which modern systems have been developed. These systems include the SESAMI, CISOC-SES, LSD, COCON and LUCY systems. These systems have previously demonstrated the possibility of elucidating structures common to organic chemistry utilizing 1H-1H COSY-connectivities, one-bond and long-range 1H-13C correlations. These systems have paved the way for the development of the most effective strategies for the application of expert systems.

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Oxepinamides A-C and Fumiquinazolines H-I: Bioactive Metabolites from a Marine Isolate of a Fungus of the GenusAcremonium

Cited by 102 publications

References 0 publications

Cottoquinazoline A and Cotteslosins A and B, Metabolites from an Australian Marine-Derived Strain of Aspergillus versicolor

Cottoquinazoline A and Cotteslosins A and B, Metabolites from an Australian Marine-Derived Strain of Aspergillus versicolor

Highly N-Methylated Linear Peptides Produced by an Atypical Sponge-Derived Acremonium sp.

CASE 2D NMR-based Expert Systems

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