PURIFICATION AND IDENTIFICATION OF ARSENIC-CONTAINING RIBOFURANOSIDES FROM THE EDIBLE BROWN SEAWEED, LAMINARIA-JAPONICA (MAKONBU)

Three water-soluble arsenic compounds were isolated from the brown alga, L. japonica, and their structures were elucidated by using 1H- and 13C-NMR spectroscopy. All were arsenosugar compounds, which had the 5-deoxy-5-dimethylarsinoyp-ribofuranoside moiety in common. Two minor compounds had a glyceryl moiety in the molecules. The major fraction, which counted for 80% of the total arsenic compounds, was found to be a mixture of very similar compounds, possibly a diastereomeric pair. Both had the dihydroxypropane sulfonate moiety in their side chains.