Low-molecular-weight compounds in Macrocystis pyrifera, a marine alga

Abstract

Small amounts of laminitol, succinic acid, glycerol, taurine, and a number of amino acids could be isolated from Macrocystis pyrifera, a brown alga. Laminitol, a C-methyl inositol, has been found previously in several red and brown algae and appears to be a common constituent in seaweeds. Glycerol may originate from enzymatic decomposition of glyceryl glycosides, while succinic acid, an intermediate in the tricarboxylic acid cycle, is likely to indicate the metabolism of microorganisms consuming carbohydrate material. Since taurines have been found only in seaweeds containing relatively large amounts of polysaccharide sulfates, the presence of this substance in M. pyrifera gives strong support to a recent hypothesis which attempts to explain the biological formation of such polysaccharide sulfates via a transesterification reaction. The free amino acids found, in the order of decreasing amounts, are l-alanine, l-aspartic acid, l-glutamic acid, l-valine, l-leucine, and proline.