Polysaccharide reductive polymerization

Inulin was identified as a major (5.9%) component of the roots of E. angustifolia (Heyl and Stanley, 1914). Giger et al. (1989) noted that polymerization of fructans occurred over the course of winter as observed by the reduction in fructose from October and May. The rate of polymerization was faster in E. purpurea than E. angustifolia, suggesting that other polysaccharides may develop in a similar manner. Additional research is needed to identify the effects of harvest time on polysaccharide composition. 

Polysaccharide and polyionite gels are different in that their spatial structure is governed by hydrogen and ionic bonds rather than by covalent bonds. The formation of polyionite gels is effected with a reduction of the ionic strength of the solution containing polycations and polyanions. An amplification of electrostatic interaction between polymeric chains takes place with the formation of a gel, in the structure of which the enzyme is incorporated. 

In the particular case of polysaccharides, this reaction has been used for the modification of several types of biopolymers with different applications [28, 29]. As an example, a monoaldehyde derivative of P CD (2) was prepared from the hydrolysis of product 1 and then grafted, by a reductive amination-type reaction, onto an alginate derivative selectively modified with adipic dihydrazide (alg-ADH) (Scheme 7.5). The new polymeric materials obtained, alg-ADH intermediate and jS-CD-grafted alginate were fully characterized in terms of chemical integrity and purity by high-resolution NMR spectroscopy [30]. 

The modified polysaccharides carrying procainamide residues have been tested for their anti-arhythmic activity by means of aconitine tests on mice. Solutions of the polymeric formulations were administered intravenously to mice. Statistical analysis of the observed responses indicated a significant anti-arrhythmic effect for the Schiff base derivatives III and V as well as for the products IV and VI, obtained via reductive alkylation of procainamide with the oxidized polysaccharides. 

During lyophilization of hyaluronan solutions, polysaccharide degradation is initiated with phosphate ions [50]. For purification from proteins, proteolitic enzymes could also be used to reduce the viscosity of the biopolymer, particularly papain SH-groups that are reducing agents and accelerate the decomposition of hyaluronan [34], Trypsin, which contains Fe " ions, could also be used for the purification of hyaluronan and to initiate the depolymerization process. The use of 8-hydroxyquinoline prevents HA viscosity reduction [25]. In order to maintain the polymerization level of hyaluronan, the initial tissue must be thoroughly washed from blood, which contains ions of iron, copper and phosphate. 

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