Polysaccharides isolation

Nicotinic acid is found in plants associated with both peptides and polysaccharides. For example in wheat bran, two forms are described a peptide with a molecular weight of approximately 12,000 and a carbohydrate complex that is called niacytin. Polysaccharides isolated from wheat bran have been found to contain 1.05% nicotinic acid in bound form. Hydrolysis yielded a fragment identified as P-3-O-nicotinoyl-D-glucose (25). 

Within the scope of this review, the contributions of the last decade concerning cell-wall polysaccharides isolated from woody and other plant tissues will be reviewed according to the above-proposed classification of hemicelluloses including larch arabinogalactans. The present review article updates and extends previous reviews [3-5] and will focus in particular on new investigated plant sources, isolation methods, structural features, physicochemical and various functional properties of hemicelluloses. Attention will also be paid to the modification of isolated hemicelluloses or hemicellulosic materials and the appHcation possibiUties of hemicelluloses and their derivatives, including their use for the production of composite materials and other biomaterials. 

Bioactive Pectic Polysaccharides Isolated from Plants. 77... 

Polysaccharides isolated from the seeds of C. chinensis have effects both as immunostimulants and as antioxidants. The polysaccharide CS-A-3-/1 has a backbone of a-D-l,4-hnked GalpA and /1-L-1,2-Rhap imits with branches at C-4 of the Rhap residues and at C-3 of GalpA residues that are composed of an arabinogalactan and glucobiose. The Ara/ imits are terminal and 1,5-... 

Polysaccharide isolation. The silk floss (36 g) was cut and extracted with 2 1 benzene-EtOH in a Soxhlet apparatus for 16 h. The residue was extracted with 2 M... 

Generalising the research into polysaccharides isolated fi om Chinese herbs Yamada (22)concludes that most biological activities are observed in the case of pectic polysaccharides. Besides, results prove that the complementarily active power of these pectins is represented mainly through the branched regions and the activity is regulated by the polygalacturonic regions. 

If branching is (1 —> 3), no glycol grouping will be present in any central unit and it may be seen that reaction will only occur on the terminal units. Such is the case with the polysaccharide laminarin, with the glucan of yeast membrane, and with a galactose-containing polysaccharide isolated from agar.146-148... 

Steinmuller, C. et al., Polysaccharides isolated from plant cell cultures of Echinacea purpurea enhance the resistance of immunosuppressed mice against systemic infections with Candida albicans and Listeria monocytogenes, Int J Immunopharmacol, 15, 605, 1993. 

They are most commonly used plasma expanders. It is polysaccharide isolated from beet sugar which is formed by the action of Leuconstec mesenteroides. It is available in mainly two forms depending upon the molecular weight. Dextran 70 (mol. wt. 70,000) available in 6% solution and Dextran 40 (mol. wt. 40,000) available in 10% solution. They are infused intravenously in the treatment of shock. Dextran 40 acts more rapidly than dextran 70. It decreases the blood viscosity and prevents the sludging of RBC s. Dextran 70 remains in circulation for longer period (upto 24 hrs) and is slowly excreted by glomerular filtration. 

A very interesting group of polysaccharides isolated from cornstarch hydrolysates are known as cyclodextrins. One of these compounds, cyclohexaamylose, is a large doughnut-shaped molecule with a central cavity that literally can engulf a small, relatively nonpolar organic molecule and hold it in water solution, similar to a micelle (Section 18-2F). As with micelles, unusual reactivity is exhibited by the bound molecules. An example is the change in the ortho-para... 

CD. see Circular dichroism Cell wall polysaccharides isolation of plant cell walls and fractionation, 697-718 neutral sugars, determination by GC of alditol acetates, 721 -732 pectin... 

Anhydrous hydrogen fluoride has been successfully applied in the structural analysis of polysaccharides to cleave glycosidic linkages since the 1980s. Recently, triflic acid has been found to be a more potent and more selective agent.774 In structural studies, for example, polysaccharides isolated from bacteria were stable toward... 

This finding is indicative of the absolute stereospecificity of the polycondensation reaction. The identity of the structure of XV with that of the natural polysaccharide isolated by a well-known method ( 1 9) from S. newington follows also from the comparison of the 13-C-NMR-spectra of both samples (see 16). 

Clapp, C. E., Dawson, I. E., and Hayes, M. H. B. (1979). Composition and properties of a purified polysaccharide isolated from an organic soil. In Proceedings, International Symposium on Peat in Agriculture and Horticulture, Schallinger, K. M., ed., Special Publication 205, Agriculture Research Organization, Bet Dagan, Israel, pp. 153-167. 

Identification and Chemical Modification of Phosphorus-Containing Endgroups in Capsular Polysaccharides Isolated from II. influenzae... 

In other cases, the evidence in favor of structure I is based upon the examination of a degraded polysaccharide isolated after controlled acid hydrolysis has resulted in removal of some or all of the acid-labile L-arabinofuranose residues without significant cleavage of D-xylopyranosyl linkages. Thus, arabinoxylans I and II would give rise to the corresponding degraded polysaccharides IV and V. Structures IV and V may be differentiated by... 

Starch from ae su kernels in a dent background consists of 51-60% amylose, as determined by the blue value procedure (Table 3.6), with the amylose percentage increasing with increasing kernel age.57 Yeh et al.,90 in contrast, reported that ae su reduced amylose concentration from 65% for su to 28% for ae su, based on SEC separation of starch polysaccharides isolated from kernels in a sweet com background. Three fractions were obtained (Table 3.7). The first two were loosely-branched, similar to the amylopectin fractions in ae. Amylose from the third peak fraction was similar in iodine staining to that from normal however, some short chain length amylose as... 

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