ABSTRACT
Polysaccharides are the most ubiquitous biopolymers. They play crucial roles in cell interaction and recognition processes, participate in structural events, and are associated with cellular differentiation and proliferation processes. The discoveries of polysaccharides, such as alginate, agar, carrageenans, chitin, chitosan, fucoidan, and porphyrin, basically from cell walls of marine organisms, all of which have shown biological activities, have been increasing significantly. Insights into the extraction processes that are used to isolate and study these molecules, from their monomeric subunits to ultimate supramolecules, and the methodologies used to discover their biological activities, are also rapidly evolving. Although the different protocols that clearly illustrate the extractions of these polysaccharides have been harnessed, they operate principally by inducing the evolution and development of these molecules. These changes have sometimes had deleterious effects on the basic structures of these polysaccharides, resulting in alteration of their molecular structural properties, and hence the purity of such molecules has been questioned. Some procedures, on the other hand, do not affect the structural properties but leave the polysaccharides half-refined, thus limiting their usage. Biological activities such as cell adhesion; recognition processes; and anticoagulant, antithrombotic, immunomodulatory, antitumor, anticancer, antilipidemic, hypoglycemic, antibiotic, anti-inflammatory, and antioxidant activities of these marine-based molecules are the reason for the ever-increasing comprehensive research undertaken to further understand them; however, the structural configuration and purity of each molecule must be unaltered for this feat to be achieved. Structural heterogeneities of these marine polysaccharides have been established; thus, the formulation of a specific extraction method designed for each polysaccharide must be established in order to ascertain that polysaccharide's optimal purity level, to elucidate its structure, and also to ensure the efficiency of its biological activity.
