The complex world of polysaccharides edited by Desiree Nedra Karunaratne

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  Preface

 

 

Biosynthesis of Bacterial polysaccharides occurs through elaborate mechanisms. The 

biosynthetic mechanisms leading to various structural changes in the O-antigens of 

bacterial polysaccharides are discussed in chapter 3. Variations in structure of the 

polysaccharides are shown to affect the biological properties and hence pathogenicity. 

Chapter 4 considers the genetic control of the biosynthesis of exopolysacchrides of 

Rhizobium leguminosarum. It is shown that diversity of the exopolysaccharides 

biosynthesized results from genetic rearrangements of the glycosyl transferase genes 

and other genes involved in translocation of the repeating units. The next chapter is 

devoted to the study of virulence and pathogenesis due to the capsular 

polysaccharides of Burkholderia pseudomallei . Several studies have been performed on 

bacterial polysaccharides as candidates for vaccines and it has been shown that 

virulence is due to changes in the capsular polysaccharide. Plant polysaccharides may 

be used for specific applications. However, the extraction of polysaccharides from 

plant waste products in timber industries with conversion of these polysaccharides 

into useful byproducts is a novel application. Chapter 6 addresses this showing that 

biomass obtained from large scale processing of Larch wood can be converted into 

valuable materials with many biological applications. The biological applications of 

the fructose rich levan polymer found abundantly in honey is discussed in the next 

chapter. The section ends with a lesser studied polysaccharide source: Lichens 

composed of a symbiotic relation between algae and fungi yielding polysaccharides 

which have been investigated for biological significance indicating antitumour, 

immunomodulatry and anti-inflammatory activities. 

Chemical and physical characterizations are important aspects when dealing with 

understanding the uses of polysaccharides in relation to their properties. The second 

section discusses methods required for characterization and estimation of spatial 

arrangement and results obtained therefrom. The five chapters in this section deal 

with physical properties, methods of characterization and chemical analysis 

techniques useful for structure determination of a range of polysaccharides from the 

animal world (chitosan) to polysaccharides from microbes (diatoms). The structural 

dynamics of chitosan, its conformation and its interactions with biological materials 

starts off this section. The importance of conformation and molecular modelling is 

known with drug design studies. Likewise the structural dynamics of polysaccharides 

are useful for identifying interactions between polysaccharides and biological entities 

as well as nanoparticles. The use of Quantum chemical methods to explain the 

template synthesis of proteoglycans is described in the next chapter. Chapter 11 in this 

section deals with some methods which are essential for elucidating the structure of a 

polysaccharide. The focus is on the use of mass spectral analysis for determining 

structures at very low concentration. Other than the basic techniques for chemical 

characterization, the application of physico-chemical techniques such as laser light 

scattering and atomic force microscopy is described in the characterization of diatom 

polysaccharides. The final chapter on biofilm matrices deals with problems 

encountered in isolation of the biofilm polysaccharides and reviews the chemical and 

physical methods available. 

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       Preface  XI 

 

The remaining two sections comprise applications of polysaccharides in the food 

industry and applications in the pharmaceutical industry. Various studies on 

polysaccharides as carriers of drugs, film formers in food protection applications 

exhibit the versatility of polysaccharides in many areas beneficial for human health. 

Section 3 deals with applications of polysaccharides in the food industry. Food 

consists of many components with proteins, fat and polysaccharides being the macro 

constituents. The composition and the interaction among the food components are 

important determinants for stability and organoleptic properties of the food item. The 

importance of polysaccharide-protein interaction and their relevance in food colloids 

is presented as a factor in emulsion stability determination in chapter 14. In the next 

chapter, the advantages of antibacterial and antioxidant activities of chitosan in 

bioactive coatings used for marine based foods, as well as exploiting the physical 

properties for gelling action and encapsulation are discussed. A whole gamut of 

functions of polysaccharides in films and coatings as carriers and protectors of 

bioactive additives and their role in improving food quality follows in chapter 16. 

Dietary fibre in food imparts health benefits. The polysaccharides cellulose and 

hemicelluloses are recognized as dietary fibres. The importance of dietary fibres for 

availability of nutrients is presented in the next chapter. The section ends with the 

advantages of starch as a source of energy. Modification of the properties of starch 

through biotechnological manipulation and production of high amylose starches is 

reviewed in this chapter. 

The final section of the book is devoted to pharmaceutical applications involving 

polysaccharides. The first two chapters deal with the use of polysaccharides as 

therapeutic agents. The well- known medicinal properties of ginseng with emphasis 

on the activity of its polysaccharides, followed by the interaction of polysaccharides 

from red sea weed with virus, starts off this section. The next three chapters are 

devoted to the use of polysaccharides as carriers of drugs. The first of these, (chapter 

21) deals with the use of beta glucans as drug delivery vehicles. Drug delivery vehicles 

using synthetic polymers as well as natural polymers have been in circulation for some 

time. With the advances in nanotechnology, nanoparticle use for drug delivery has 

taken the centre stage. This chapter looks into formation of glucan nanoparticles to 

enhance the property of the drug delivery vehicle. Chapter 22 on the other hand 

presents the formation of supramolecular complexes for efficient delivery of poorly 

water soluble drugs. On a different note, the effect of dietary fibre on availability of 

drugs with chitosan as the dietary fibre is evaluated in the next chapter. In conclusion, 

the long standing debate on the use of polysaccharides as vaccines and the future 

direction of carbohydrates as successful candidates is argued. 

As evident from the diversity of the applications of polysaccharides presented in this 

book, study of carbohydrates brings us to a rare world where the abundance of 

sources and variety of structures is both mind boggling and intriguing. Carbohydrates 

have been explored since the beginning of chemical investigations and 

polysaccharides will continue to exert its sweet essence on researchers dabbling in the 

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