Studies on some plant polysaccharides
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Date
1985-07
Authors
De Silva, S. Shyamali M.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya
Abstract
The thesis consistsof four parts. The first part describes the isolation and structural investigations of a water=-goluble arabinoxylan from Neolitsea cassia_(Lauraceae). The glycosyl composition and glycosyl linkage composition analyses were carried out using ,formula> and 130-n.m.r. spectroscopy. The arabinoxylan was shown to be composed of a ,formula> linked zylopyranosyl backbone which is fully substituted with L- arabinofuranosyl side=-chains. Terminal <formula> residues were found to be predominantly attached to 0=3 of the xylopyranosyl backbone whereas short side~chains of 3 wlinked <formula>residues, terminsted with <formula> residues were found to be . predominantly sttached to<formula> of the xylopyramosyl backbone. The second part of the thesis deals with the isolation of some polysaccharides from Cyclea burmanni (Menispermaceae). The water=soluble polysaccharide was found bo be a pectin by the neutral sugar composition and uronic acid content which were d;'bermined by gel.ce. and the decarboxylation procedure respectively. Ion=—exchange chromatography of the pectin gave four fractions having different uronic acid and neutral sugar contents. Glycosyl composition analysis of the fractions obtained by gel=permeation cliomatography of a partially degraded pectin showed the distribution of each - - newtral suger. The polysaccheride fraction isolated from C. burmeuni by EDTA was composed of more neutral sugars and jess uronic acids than the water=soluble pectine. The polysaccharide fraction cbtained from the aslkali extract was composed mainly of xylose and glucose while uronic acids were completely sbsent, The investigetion on the effect of water and pB-glucanase treatment on low and high viscous barley = Hordeum sp. (Grarineae) is described in the third part of this thesis. The barley g=-glucans and pentosans which contribute to the high viscosity of water extracts of barley were found to have degraded. after (i) water treatment end f=-glucanase treatmernt. The 2l part of the thesis describes the separation of some polysaccharide fractions from a brown seaweed, Turbiraria conoides (Phaeophyceae) by sequential extraction. The sugar composition of each fraction was analysed by geleCe Alginic <formula> was isolated with sodium carbonate by sequential extraction as well as direct extraction. The composition and sequence of <formula> <formula> residues in the isolated alginate were determined by high resolution <formula> and <formula> These alginates were compared with those isolated by sequential and direct extraction from three other species = 3 - of brown seaweeds, nemely Cystoseira trinodis and two unidentified species of Sargagsum viz. Sargassum Sp.(linear) and Sargassum spe(oval) o Three of the sequentially extracted slginates Lad more of m—;sguluronate residues when analysed <formula> and <formula> spectroscopy. Two of the direct extracted samples also had more of <formula> regidues when analysed by 1H-«n.m.r. spectrcscopy. The alginate isolated by direct extraction from Szrgassum sp. {oval) was found to contain more J<formula> residues.
Description
Keywords
Plants , Polisaccharides , Sri Lanka