**4.4 Sulfated polysaccharides**

There are substances called polysaccharides in plants, animals, algae, microbes, and other natural products. They comprise numerous monosaccharides connected by various glycosidic linkages and contain polymeric carbohydrate structures. Sulfated polysaccharides are of non-animal origin and are most abundant. Most sulfated polysaccharides found in nature are complex combinations of molecules with a wide range of structures and activity [71]. They frequently occur in nature. Sulfated polysaccharides with a variety of biological functions are primarily found in seaweed. Fucoidan is a complex sulfated polysaccharide that is present mainly in the cell wall fluid of several species. It contains L-fructose and sulfate, ester groups.

Some of the important metabolites found in different algal species are listed in **Table 3**.
