title: Dolabellanes with antibacterial activity from the brown alga Dilophus spiralis.
abstract: Seventeen diterpenes featuring the dolabellane skeleton (1-17) were isolated from the organic extracts of the brown alga Dilophus spiralis. Seven compounds are new natural products (1, 3, 5, 6, 11, 14, 15) and eight are structurally revised (2, 4, 7-10, 12, 13), among which three are reported for the first time from a natural source (4, 9, 10). The structure elucidation and the assignment of the relative configurations of the isolated natural products were based on detailed analyses of their spectroscopic data. The structure of metabolite 10 was confirmed by single-crystal X-ray diffraction analysis, whereas the absolute configurations of compounds 2, 4-10, 12, and 13 were determined using the modified Mosher's method on the semisynthetic product 18 and chemical interconversions. The antibacterial activities of compounds 1-18 were evaluated against six strains of Staphylococcus aureus, including multidrug- and methicillin-resistant variants.
authors.affiliation: Department of Pharmacognosy and Chemistry of Natural Products, School of Pharmacy, University of Athens, Panepistimiopolis Zografou, Athens 15771, Greece.
authors.forename: Efstathia
authors.initials: E
authors.lastname: Ioannou
authors.forename: Antonio
authors.initials: A
authors.lastname: Quesada
authors.forename: M Mukhlesur
authors.initials: MM
authors.lastname: Rahman
authors.forename: Simon
authors.initials: S
authors.lastname: Gibbons
authors.forename: Constantinos
authors.initials: C
authors.lastname: Vagias
authors.forename: Vassilios
authors.initials: V
authors.lastname: Roussis
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D006115:Greece; D016106:Methicillin Resistance / Q000187:drug effects; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D000459:Phaeophyceae / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D004224:Diterpenes; C115566:dolabellane