Sulfated polysaccharides from algae: Characteristic structures and their medicinal applications

Sulfated polysaccharides, in which at least some of the hydroxyl groups of the sugar residues are substituted by sulfate groups, are universal and characteristic ingredients of algae. So far, various types of polysaccharides have been isolated from algae and studied their chemical structures. Sulfated galactans including carrageenans and agaroids and sulfated fucans (fucoidans) are well known sulfated polysaccharides isolated from red algae and brown algae, respectively. Various types of sulfated polysaccharides have been isolated from green and blue-green algae. On the other hand, sulfated polysaccharides are well known to possess multiple biological activities such as anticoagulant, antiviral, antitumor, antioxidant and immunomodulating effects. Therefore, algal sulfated polysaccharides are promising candidates for developing novel pharmaceuticals. In addition, the third function of food has been attracted a great deal of attention to maintain human health, recently, therefore, it is possible to develop functional foods based on the biological potencies of sulfated polysaccharides. In this chapter, we will summarize the chemical characteristics and biological activities of sulfated polysaccharides from algae.