A new linear diterpene, isolated from the brown alga Bifurcaria bifurc
ata collected on the Atlantic coasts from Morocco, has been characteri
zed by spectral methods and chemical reactions. This compound revealed
a potent cytotoxicity to fertilized sea urchin eggs which was compare
d to that of previously described acyclic diterpenes. The seasonal and
geographical variations in the diterpenoid composition of this specie
s are also studied and the results discussed.