Four new cyclized diterpenes, one xenicane (1) and three dolabellanes (2-4), were isolated, along with seven previously reported metabolites [3beta-hydroxydilophol (5), dictyols E (6) and C (7), hydroxycrenulide (8), 9-acetoxy-15-hydroxy-1,6-dollabelladiene (9), hydroxyacetyldictyolal (10), and fucoxanthin], from a Mediterranean species of Dictyota sp. collected in Le Brusc Lagoon (French Mediterranean coast). Their structures, as well as their relative configurations, were determined through extensive spectrometric (IR, HRESIMS, 1D and 2D NMR) data analysis and molecular modeling studies and by comparison with those reported in literature. Some of the isolated metabolites were evaluated for their antiadhesion activity against a marine bacterial biofilm (Pseudoalteromonas sp. D41).

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The present study was carried out in order to determine the phytochemical composition of the marine brown alga Cystoseira foeniculacea collected off the coasts of Algeria. After a preliminary fractionation of its organic crude extracts by column chromatography, the resulting fractions were further analysed by 1 H NMR. Even though algal species of the genus Cystoseira are commonly known to produce a wide variety of meroditerpenoids, in the case of C. foeniculacea none of the fractions were found to contain such compounds: most of the fractions showed typical 1 H NMR signals of fatty acids and derivatives (mainly glycerolipids and glycolipids). Nevertheless, the thorough analysis of a sterol-enriched fraction by RP-C 8 HPLC led to the isolation, for the first time from this species, of fucosterol (1) and a mixture of saringosterols (2 and 3). The NMR data of compounds 1-3 were fully determined with the help of 1D and 2D experiments which allowed the reassignment of some attributions in comparison with those reported in the literature. This work also confirms evidence of the oxidative degradation of fucosterol into a C-24 epimeric mixture of saringosterols. ª 2014 Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Dictyotadimer A, a New Dissymmetric Bisditerpene from a Brown Alga of the Genus Dictyota. -(VIANO, Y.; BONHOMME, D.; ORTALO-MAGNE, A.; THOMAS, O. P.; EL HATTAB, M.; PIOVETTI, L.; BLACHE, Y.; CULIOLI*, G.; Tetrahedron Lett. 52 (2011) 9, 1031-1035, http://dx.doi.org/10.1016/j.tetlet.2010.12.095 ; Lab. MAPIEM EA 4323, Univ. Toulon-Var, F-83957 La Garde, Fr.; Eng.) -Mais 22-202