Polar acyclic diterpenoids from Bifurcaria bifurcata (Fucales, Phaeophyta)

Five polar linear diterpenoids, together with three known related compounds, have been isolated from the brown alga Bifurcaria bifurcata collected off the French Atlantic coast. These metabolites have been identified as hydroxylated derivatives of 13-oxo- and 13-hydroxygeranylgeraniol. The absolute configuration of the 13-position has been determined, for the 13-hydroxygeranylgeraniol derivatives, to be R by means of a modified Mosher's method. These data were used for chemotaxonomical purposes.