Marine Polysaccharides from Algae

Abstract

The marine world has a unique ecological environment, providing extraordinary biodiversity and related chemical diversity. The structure and chemical properties of bioactive natural products in the ocean are usually not possessed by terrestrial natural products (Moghadamtousi et al., 2015). These bioactive substances can be divided into many structural types, including polysaccharides, glycosides, peptides, terpenes, sterols, polyethers, alkaloids, macrolides and unsaturated fatty acids. Marine natural products have obvious curative effects on various human diseases. Therefore, many new compounds isolated from marine organisms have been applied to biochemical and pharmaceutical research (Laurienzo, 2010). At the end of 1950, Bergmann officially reported the first marine natural product with biological activity (Malve, 2015). Humans initially regarded carbohydrates as a source of energy and cellulose in food. Polysaccharides and their conjugates (glycoproteins, glycolipids, etc.) are involved in the regulation of various cell life phenomena. They are immunomodulators. It can activate immune cells and improve the immune function of the body without side effects on normal cells. Therefore, polysaccharides, as antineoplastic drugs, treatment of AIDS and other antiviral drugs and anti-aging drugs, have shown more and more application prospects in clinic. Marine polysaccharides have been found to be the most important biological macromolecules in a large number of marine extracts. Agar polysaccharide sulfate, carrageenan polysaccharide sulfate and kelp polysaccharide sulfate have been used in clinic for their anticoagulant, lipid-lowering and hemostatic effects. Marine polysaccharides with different structural characteristics widely exist in various marine species (Wang et al., 2012), such as marine animals (Fonseca et al., 2009; Laurienzo, 2010; Singh et al., 2000; Zierer and Mourão, 2000), marine plants and marine microorganisms (Debbab et al., 2010; Thomas et al., 2010; Waters et al., 2010). Among various marine species, agar, carrageenan and algin from seaweed are used as culture medium, suspending agent and emulsifier in biochemistry and medicine.