The sterols from marine brown algae (Class: Phaeophyceae).

General features of marine steroids are briefly described with some emphasis on the sterols from algae, and mainly those from marine brown algae, class Phaeophyceae, which are comprehensively reviewed here. The structures, sources, distribution and artifacts generation are reported, together with new data on Brazilian Dictyotales and Fucales. A biogenetic proposal for the side chains formation is presented, including the rearranged structures for the which no biogenetic hypothesis had been reported in the literature. Some considerations are made on the potential use of brown algae sterols in algal taxonomy.