ABSTRACT
Among the different bioactive compounds obtained from the sea, polysaccharides have been gaining interesting and valuable applications in the food and pharmaceutical elds. As they are derived from natural
15.1 Introduction ................................................................................................................................................................... 209 15.2 Production of polysaccharides by marine sources .................................................................................................. 210 15.3 Major marine polysaccharides .................................................................................................................................... 210
15.3.1 Chitosan ............................................................................................................................................................. 210 15.3.1.1 Chemical structure ............................................................................................................................ 210 15.3.1.2 Method of manufacture .................................................................................................................... 210 15.3.1.3 Properties of chitosan .........................................................................................................................211 15.3.1.4 Chitosan derivatives ...........................................................................................................................211 15.3.1.5 Applications of chitosan and its derivatives .................................................................................. 212
15.3.2 Carrageenan ...................................................................................................................................................... 213 15.3.2.1 Sources and production of carrageenan ..........................................................................................214 15.3.2.2 Properties of carrageenan ..................................................................................................................214 15.3.2.3 Applications of carrageenan ............................................................................................................. 215
15.3.3 Alginate ...............................................................................................................................................................216 15.3.3.1 Properties of alginate..........................................................................................................................216 15.3.3.2 Applications ........................................................................................................................................ 217
15.4 Other marine polysaccharides .................................................................................................................................... 218 15.4.1 Sulfated polysaccharides ................................................................................................................................. 218
15.5 Future directions ........................................................................................................................................................... 219 15.6 Conclusion ..................................................................................................................................................................... 219 References ................................................................................................................................................................................ 220
sources, they are easily available, nontoxic, cheap, biodegradable, and biocompatible. Polysaccharides can be obtained from a number of sources including seaweeds, plants, bacteria, fungi, insects, crustaceans, and animals, and can be structurally tuned through genetic engineering. The term “polysaccharide” encompasses very diverse and large carbohydrates that may be composed of only one kind of repeating monosaccharide (termed homo-polysaccharides or homoglycans; e.g., cellulose) or formed by two or more different monomeric units (hetero-polysaccharides or heteroglycans; e.g., agar, alginate, carrageenan). The conformation of the polysaccharide chains is markedly dependent not only on the pH and ionic strength of the medium, particularly in the case of polyelectrolytes, but also on the temperature and the concentration of certain molecules. Polysaccharides are divided into two subtypes: anionic and cationic. Several anionic and cationic polysaccharides are widely available in nature and have gained keen interest in the food and pharmaceutical elds (Colquhoun et al. 2001, Guezennec 2002, Coviello et al. 2007, D’Ayala et al. 2008). The biological activity of naturally occurring polysaccharides has been increasingly utilized for human applications and creating a strong position in the biomedical eld. Because of their different chemical structures and physical properties, these natural sources can be used in the different applications, from tissue engineering to the preparation of drug vehicles for controlled release. This chapter focuses on the present use and the diverse applications of marine polysaccharides in the pharmaceutical sector.
