Phlorotannins from the brown algae Cystophora torulosa and Sargassum spinuligerum.

Phlorotannins often have various toxic effects against a large number of organisms. From the ethyl acetate fraction of the ethanolic extract of the brown alga Cystophora torulosa 33 phlorotannins were obtained. Twenty of them are described in this report: phlorethols and fuhalols, and fucophlorethols and hydroxyfucophlorethols. Seven of them were isolated for the first time. New phlorotannins bearing additional hydroxy groups belong to the hydroxyfucophlorethols. NMR- and MS-data were used for structural elucidation. Several of the substances described for C. torulosa occur in Sargassum spinuligerum as well.