Trihydroxylated linear diterpenes from the brown alga Bifurcaria bifurcata.

Two novel polar diterpenes were isolated from the brown alga Bifurcaria bifurcata collected off the Atlantic coast of Morocco, and their structures established by spectral methods. Both compounds are trihydroxylated acyclic diterpenes derived from 12-hydroxygeranylgeraniol. They were tested in vitro for their cytotoxicity and proved to be active against the NSCLC-N6 cell line. Their absolute configuration at the C-12 position has been determined with a modified Mosher's method [J. Am. Chem. Soc. 113 (1991) 4092] and that of the 12-hydroxygeranylgeraniol (bifurcadiol) has been revised.