title: Novel extracellular diterpenoids with biological activity from the cyanobacterium Nostoc commune.
abstract: Five novel extracellular metabolites with an unprecedented diterpenoid skeleton, 5-[(5-carboxy-2-hydroxy)benzyl]-11-hydroxymethyl-2,5,6,8a, 11-pentamethyldodecahydrocyclopenta<a>naphthalene (1), 5-[(5-carboxy-2-hydroxy)benzyl]-11-formyl-2,5,6,8a, 11-pentamethyl-dodecahydrocyclopenta<a>naphthalene (2), 5-[(5-carboxy-2-hydroxy)benzyl]-11-carboxy-2,5,6,8a, 11-pentamethyl-dodecahydrocyclopenta<a>naphthalene (3), 5-[(5-carboxy-2-hydroxy)benzyl]-11-dihydroxymethyl-2,5,6,8a, 11-pentamethyldodecahydrocyclopenta<a>naphthalene (4), and 5-[(5-carboxy-2-hydroxy)benzyl]-11-acetyl-2,5,6, 8a-tetramethyldodecahydrocyclopenta<a>naphthalene (5), have been isolated from the culture medium of the terrestrial cyanobacterium Nostoc commune by means of bioguided isolation. The molecules were designated as comnostins A-E. The structures were determined by spectroscopic methods, mainly NMR and mass spectrometry. The relative stereochemistry of comnostin A was confirmed by single-crystal X-ray structure analysis. All comnostins showed antibacterial activities. Additionally, cytotoxic and molluscicidal activities were found for comnostin B.
authors.affiliation: Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Jaki
authors.forename: J
authors.initials: J
authors.lastname: Orjala
authors.forename: J
authors.initials: J
authors.lastname: Heilmann
authors.forename: A
authors.initials: A
authors.lastname: Linden
authors.forename: B
authors.initials: B
authors.lastname: Vogler
authors.forename: O
authors.initials: O
authors.lastname: Sticher
mesh_terms: D000458:Cyanobacteria / Q000737:chemistry*; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D015394:Molecular Structure; D013057:Spectrum Analysis; D014407:Tumor Cells, Cultured
chemical_list: D004224:Diterpenes