**3. The Structure Characterization**

With the effort of the scientific community, several fucoidans' structures have been elucidated, and their biological activities have been identified [3]. The structure of fucoidans is complex in nature and it is very difficult to elucidate the general structure due to their heterogenous nature [4]. However, the majority of algal fucoidans consist of a linear backbone of random 1 → 3 or 1 → 4 linked α-L-fucopyranose residues periodically interrupted by other monosaccharides. Sulfate ester groups are arbitrarily substituted at 2, 3 and/or 4 positions of fucopyranose units, making it a highly heterogenous polymer [1,5].
