Molecular characteristics of the water-soluble polysaccharides from Anoectochilus formosanus Hayata
Date Issued
2005
Date
2005
Author(s)
Ruan, Chang-Ting
DOI
zh-TW
Abstract
Cytokine stimulating activity of Anoectochilus formosanus on human peripheral blood nuclear cells has been associated with its water-soluble polysaccharides. To study the molecular characteristics of these polysaccharides, the polysaccharide enriched fractions were prepared from hot-water extracts of whole plant through protease and amylase digestion and collected with ethanol precipitation. The yield of water-soluble polysaccharide fraction (AFP) accounted for 3.03% of dried mass. The AFP was further separated into neutral (AFPN) and acidic (AFPA) fraction by DEAE-anion-exchange chromatography with yields of 47.6% and 30.9% of AFP, respectively. The AFPN was composed of two linear homopolysaccharides, a galactan and a mannan, which can be separated by selecting precipitation of Fehling’s solution through copper (II) ion and mannan complex formation. The glycosidic linkage of both polysaccharide were found to be β-(1→4) revealed by 13C-NMR analyses. The apparent molecular weight of the galactan and the mannan were 21.2 and 52.7 kDa, respectively, according size-exclusion chromatographic analyses. The acidic polysaccharide fraction (AFPA) was found to be a complicate polysaccharide mixture. The major components of acidic fraction were pectic polysaccharides which were compose of 78.6% of galacturonic acid and showed characteristic of rhamnogalactan II and (1→3, 1→6)-β-D-galactan. One proteoglycan was collected in acidic fraction from low anionic strength eluting portion of DEAE-chromatography. The proteoglycan contents 58.4% protein and 41.6% glycan with molecular weight of 51.5 kDa. The sugar compositions of the glycan were arabinose, galactose, glucose and mannose in a molar ratio of 29.8: 35.1: 10.3: 23.8.
Subjects
多醣
分子結構
果膠質多醣
Anoectochilus formosanus
polysaccharides
molecular characteristics
pectic polysaccharides
arabinogalactans
Type
thesis
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