Arabinogalactans isolation

Luettig, B., Steinmiiller, C., Gifford, G., Wagner, H., and Lohmann-Matthes, M. 1989. Macrophage activation by the polysaccharide arabinogalactan isolated from plant cell cultures of Echinacea purpurea. J. Natl Cancer Inst. 81, 669-675. 

P. Odonmazig, A. Ebringerovd, E. Machova, and J. Alfoldi, Structural and molecular properties of the arabinogalactan isolated from Mongolian larchwood (Larix dahurica L.), Carbohydr. Res., 252 (1994) 317-324. 

Weak oncolytic activity has been reported from pentane extracts against Walker carcinoma 256 and P-388 lymphocytic leukemia, but not lymphoid leukemia. The acidic arabinogalactan isolated from E. purpurea tissue culture activated macrophages to cytotoxicity against tumor cells and Leishmania enriettii, in addition to stimulating macrophages to produce TNF, IL-1, and IF-P2, and a slight increase in T-cell prohferation. ... 

Arabinogalactans have been isolated from the tissues of a variety of dicots. However, no arabinogalactan has been isolated from a source known to contain only primary cell walls. The glycosyl compositions of the arabinogalactans isolated from rapeseed cotyledons, rapeseed flour, larch wood, maple sap, the medium of suspension-cultured tobacco cells, the medium of suspension-cultured sycamore cells, and from soybean cotyledons are summarized in Table 2. 

Larm, O., O. Theander, and P. Aman Structural Studies on a Water-soluble Arabinogalactan Isolated from Rapeseed (Brassica napus). Acta Chem. Scand. B 30, 627 (1976). 

Polysaccharides of Soybean Seeds. II. A Methylated Arabinogalactan Isolated from Methylated Product of Hot-Water-Extract Fraction of Soybean Seed Polysaccharides. Agr. Biol. Chem. 29, 626 (1965). 

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. 

Arabinogalactans (AGs) are widely spread throughout the plant kingdom. Many edible and inedible plants are rich sources of these polysaccharides. AGs occur in two structurally different forms described as type I and type II, associated with the pectin cell-wall component by physical bonds and some of them are covalently linked to the complex pectin molecule as neutral side chains. Commercial pectins always contain AG 10-15%). AG of type I has a linear (1 4)-y0-o-Galp backbone, bearing 20-40% of of-L-Ara/ residues (1 5)-linked in short chains, in general at position 3. It is commonly found in pectins from citrus, apple and potato [6]. Recently, this AG type has been isolated from the skin of Opuntia ficus indica pear fruits [372]. 

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-... 

Mild, acid hydrolysis of European-larch arabinogalactan results in the formation of 3-0-/3-L-arabinopyranosyl-L-arabinose (XXXIX). 26 Although this disaccharide has been isolated as an acid-reversion product from L-arab-inose,131 it is accompanied under these conditions by two other arabinose-containing disaccharides, neither of which was detected in the larch polysaccharide hydrolyzate. Since hydrolysis of methylated -galactan gave approximately equimolar proportions of 2,3,4-tri-O-methyl-L-arabinose and 2,5-di-O-methyl-n-arabinose, traces of 2,3,5-tri-O-methyl-L-arabinose, and no mono-O-methyl-L-arabinose, it is clear that the L-arabinose units must arise from an arabinogalactan rather than from an arabinan, and that the majority of these must be present in 3-0-/3-L-arabinopyranosyl-L-arabino-furanose side-chains (XLV) linked, in some way as yet unknown, to the framework of D-galactose units (XLI). 

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