Eutypoids B−E Produced by aPenicilliumsp. Strain from the North Sea

Crude extracts of the Penicillium sp. strain KF620 isolated from the North Sea showed antimicrobial activities against Xanthomonas campestris and Candida glabrata. Purification of the extracts led to the isolation of the new aromatic butenolides eutypoids B (1), C (2), D (3), and E (4). Their structures were elucidated by NMR spectroscopy and supported by HRESIMS and UV data. The antibacterial activity of the crude extracts was due to the presence of the known diketopiperazine fellutanine (cyclo(Trp-Trp)). The eutypoids were neither cytotoxic nor antibacterial, but inhibited the activity of glycogen synthase kinase-3

Nocapyrones A−D, γ-Pyrones from aNocardiopsisStrain Isolated from the Marine SpongeHalichondria panicea

Four new γ-pyrones, nocapyrones A−D (1−4), were isolated from an organic extract of the Nocardiopsis strain HB383, which was isolated from the marine sponge Halichondria panicea. These are the first γ-pyrones reported from a Nocardiopsis strain. The structures were elucidated on the basis of one- and two-dimensional NMR experiments and supported by HPLC-UV/MS and HRESIMS analyses. The biosynthesis of nocapyrone A was investigated by feeding experiments with 13C-labeled compounds. In addition, one diketopiperazine, which was only known as a synthetic compound before, was isolated. The bioactivies of 1, 2, and the diketopiperazine were evaluated in a panel of assays

Levantilides A and B, 20-Membered Macrolides from a Micromonospora Strain Isolated from the Mediterranean Deep Sea Sediment

Two new 20-membered macrolides, levantilide A and B, were isolated from the Micromonospora strain M71-A77. Strain M71-A77 was recovered from an Eastern Mediterranean deep-sea sediment sample and revealed to produce the levantilides under in situ salinity of 38.6‰. The chemical structures of the levantilides were elucidated on the basis of different one- and two- dimensional NMR experiments. Levantilide A exhibits a moderate antiproliferative activity against several tumor cell lines

Diacidene, a polyene dicarboxylic acid from a Micromonospora isolate from the German Wadden Sea

Micromonospora sp. strain DB620 was isolated from a Wadden Sea sediment sample collected near Büsum (Germany) and is closely related (99% 16S-rRNA gene sequence similarity) to Micromonospora coxensis strain MTCC8093. It produced a new polyene dicarboxylic acid named diacidene (1) and in addition a derivative of chorismic acid, the known 3-[(1-carboxyvinyl)oxy]benzoic acid. The structure elucidation of 1 was achieved by applying different 1D and 2D NMR techniques as well as mass spectrometry and UV spectroscopy

Malettinin E, an antibacterial and antifungal tropolone produced by a marine Cladosporium strain

The isolation and structure elucidation of malettinins A–C (1–3) along with the new malettinin E (4) are described. The compounds were produced by the fungus Cladosporium sp. strain KF501, which was isolated from the German Wadden Sea. The malettinins are built up of tropolone/dihydropyran ring structures linked to a furan ring. The structure elucidation of the isolated compounds was achieved by means of one- and two-dimensional NMR spectroscopy supported by mass and UV data. The relative configuration of 4 was determined on the basis of single-crystal X-ray diffraction analysis. 1–4 exhibited antibacterial and antifungal activities when profiled against Xanthomonas campestris and Trichophyton rubrum. The influence of the chemical structure of the furan ring and of configurational changes on biological activities was observed

Mayamycin, a Cytotoxic Polyketide from aStreptomycesStrain Isolated from the Marine SpongeHalichondria panicea

A new benz[a]anthracene derivative called mayamycin (1) was identified in cultures of Streptomyces sp. strain HB202, which was isolated from the marine sponge Halichondria panicea and selected because of its profound antibiotic activity. The ability to produce aromatic polyketides was indicated by genetic analyses, demonstrating the presence of a type II polyketide synthase. The production of mayamycin (1) was induced by variation of the culture conditions. The structure of 1 was elucidated by HPLC-UV/MS and NMR spectroscopy. Mayamycin (1) exhibited potent cytotoxic activity against eight human cancer cell lines and showed activity against several bacteria including antibiotic-resistant strains

Calcarides A–E, Antibacterial Macrocyclic and Linear Polyesters from a Calcarisporium Strain

Bioactive compounds were detected in crude extracts of the fungus, Calcarisporium sp. KF525, which was isolated from German Wadden Sea water samples. Purification of the metabolites from the extracts yielded the five known polyesters, 15G256α, α-2, β, β-2 and π (1–5), and five new derivatives thereof, named calcarides A–E (6–10). The chemical structures of the isolated compounds were elucidated on the basis of one- and two-dimensional NMR spectroscopy supported by UV and HRESIMS data. The compounds exhibited inhibitory activities against Staphylococcus epidermidis, Xanthomonas campestris and Propionibacterium acnes. As the antibacterial activities were highly specific with regard to compound and test strain, a tight structure-activity relationship is assumed

Geranylphenazinediol, an Acetylcholinesterase Inhibitor Produced by a Streptomyces Species

Geranylphenazinediol (1), a new phenazine natural product, was produced by the Streptomyces sp. strain LB 173, which was isolated from a marine sediment sample. The structure was established by analysis of NMR and MS data 1 inhibited the enzyme acetylcholinesterase in the low micromolar range and showed weak antibacterial activity. In order to get a more detailed picture of the activity profile of 1, its inhibitory potential was compared to that of related structures

Phylogenetic Identification of Fungi Isolated from the Marine Sponge Tethya aurantium and Identification of Their Secondary Metabolites

Fungi associated with the marine sponge Tethya aurantium were isolated and identified by morphological criteria and phylogenetic analyses based on internal transcribed spacer (ITS) regions. They were evaluated with regard to their secondary metabolite profiles. Among the 81 isolates which were characterized, members of 21 genera were identified. Some genera like Acremonium, Aspergillus, Fusarium, Penicillium, Phoma, and Trichoderma are quite common, but we also isolated strains belonging to genera like Botryosphaeria, Epicoccum, Parasphaeosphaeria, and Tritirachium which have rarely been reported from sponges. Members affiliated to the genera Bartalinia and Volutella as well as to a presumably new Phoma species were first isolated from a sponge in this study. On the basis of their classification, strains were selected for analysis of their ability to produce natural products. In addition to a number of known compounds, several new natural products were identified. The scopularides and sorbifuranones have been described elsewhere. We have isolated four additional substances which have not been described so far. The new metabolite cillifuranone (1) was isolated from Penicillium chrysogenum strain LF066. The structure of cillifuranone (1) was elucidated based on 1D and 2D NMR analysis and turned out to be a previously postulated intermediate in sorbifuranone biosynthesis. Only minor antibiotic bioactivities of this compound were found so far