The active carbohydrate metabolites of the brown seaweed, Fucus vesiculosis

Abstract

Biosynthetic studies with Na 2 14CO 3 on Fucus vesiculosus by Bidwell 2 have shown that d-mannitol is the main respiratory substrate, but that a proportion of the radioactivity is incorporated into fucoidin, alginic acid, alkali-soluble alcohol-soluble material, and into the insoluble residue remaining after the removal of the other materials by acid and alkali extraction. The quantity of seaweed used in the biosynthetic studies prevented a complete investigation of the various materials. Large-scale extraction, under the conditions used in the above studies, has now revealed that the “fucoidin” is indeed a mixture of fucoidin and laminarin, and that the “alginic acid” is contaminated with a sulphated glucuronoxylofucan which has been found in this genus for the first time. The alkali-soluble, alcohol-soluble material is a partially degraded portion of this glucuronoxylofucan. Further extraction of the insoluble residue gives additional, crude glucuronoxylofucan, and an acid-insoluble and an acid-soluble glucan are separated by extraction with 6 n alkali after mild treatment with chloride. Tentative evidence is advanced for the presence of (1 → 3)- and (1 → 4)-linked d-glucose units in these glucans and in the final residue.