Fucols and Phlorethols from the Brown Alga Scytothamnus australis Hook. et Harv. (Chnoosporaceae)

Abstract

Eight fucols and two phlorethols were isolated by HPLC from the ethanolic extract of the brown alga Scytothamnus australis, . Because of their instability the substances were peracetylated before isolation. The phlorotannins trifucolnonaacetate, tetrafucol-A-dodecaacetate, tetrafucol-B-dodecaacetate, cis-pentafucol-A-pentadecaacetate, diphlorethol-A-pentaacetate and triphlorethol-A-heptaacetate have been characterized previously. In addition to these substances we found hydroxytetrafucol-B-tridecaacetate, pentafucol-B-pentadecaacetate, cis, trans-pentafucol-A-pentadecaacetate and hexafucol-B-octadecaacetate all of which are described for the first time. The elucidation of their structure was achieved by 1 H NMR, 13 C NMR, 1 H 1 H ROESY NMR and mass spectral data.