CONSTITUTION OF THE GALACTOMANNAN FROM THE KERNEL OF GREEN PALMYRA PALM NUT (BORASSUS FLABELLIFER LINN.)

1961 ◽  
Vol 39 (7) ◽  
pp. 1408-1418 ◽  
Author(s):  
A. K. Mukherjee ◽  
D. Choudhury ◽  
P. Bagchi

The water-soluble polysaccharide extracted from the kernel of green palmyra palm nut (Borassusflabellifer Linn.) was shown to be composed of D-galactose and D-mannose in the proportion of 1:2.4. Hydrolysis of the fully methylated galactomannan yielded 2,3,4,6-tetra-O-methyl-D-galactose, 2,3,6-tri-O-methyl-D-mannose, and 2,3-di-O-methyl-D-mannose in the molar ratio of 1:1.4:0.95. Partial hydrolysis of the galactomannan afforded 4-O-β-D-mannopyranosyl-D-mannose, 6-O-α-D-galactopyranosyl-D-mannose, and two trisaccharides. Based on these results a structural formula for the galactomannan has been proposed, additional evidence for which was adduced from periodate-oxidation studies.

1958 ◽  
Vol 36 (5) ◽  
pp. 755-762 ◽  
Author(s):  
G. A. Adams

A water-soluble polysaccharide isolated from white spruce wood contained D-galactose, L-arabinose, and D-xylose in a molar ratio of 21:3:1. Hydrolysis of the fully methylated polysaccharide yielded 2,3,5-tri-O-methyl-L-arabinose (12 moles); 2,3,4,6-tetra-O-methyl-D-galactose (29 moles); 2,3,4-tri-O-methyl-D-galactose (34 moles); 2,6-di-O-methyl-D-galactose (0.5 moles); 2,4-di-O-methyl-D-galactose (45 moles); 2,3-di-O-methyl-D-xylose (5 moles); and monomethyl xylose (1 mole). When oxidized by periodate the polysaccharide consumed 1.18 moles of oxidant, and yielded 0.56 moles of formic acid per mole of anhydro-D-galactose. The D-xylose was attributed to the presence of a xylan mixed with the arabogalactan in the original polysaccharide preparation. The methylation and periodate oxidation data showed that the arabogalactan possessed a highly branched structure with the anhydro-D-galactose units being joined by 1 → 3 and 1 → 6 glycosidic bonds. All of the L-arabinose was present in the furanoside form as non-reducing terminal units.


1957 ◽  
Vol 35 (6) ◽  
pp. 556-564 ◽  
Author(s):  
G. A. Adams

Extraction of beechwood chlorite holocellulose with hot water yielded a hemicellulose in 13.4% yield (based on original extractive-free wood) containing D-xylose 72%, D-galactose 11.0%, and uronic acid 13.2%. Purification of the crude hemicellulose by complexing with Fehling's solution yielded a chemically homogeneous fraction containing D-xylose 83% and 4-O-methyl-D-glucuronic acid 15.5%. Hydrolysis of the fully methylated hemicellulose yielded 2,3,4-tri-O-methyl-D-xylose, 2,3-di-O-methyl-D-xylose, 3-O-methyl-D-xylose, and 3-O-methyl-2-O-(2,3,4-tri-O-methyl-D-glucopyranosyluronic acid)-D-xylose in a molar ratio of 2:35:3:5. On the basis of the methylation data, periodate oxidation, reducing power determinations, and weight average molecular weight values a possible structure for the hemicellulose is proposed.


1963 ◽  
Vol 41 (6) ◽  
pp. 1381-1388 ◽  
Author(s):  
E. C. A. Schwarz ◽  
T. E. Timell

An arabino-4-O-methylglucuronoxylan (10:14:76), a water-soluble galactoglucomannan (1:1:3), and an alkali-soluble galactoglucomannan (0.1:1:3) have been isolated in yields of 7, 4, and 8% from the wood of amabilis fir (Abies amabilis). The structure of the polysaccharides was established by methylation and periodate oxidation techniques. The xylan ([Formula: see text]) contained side chains of (1 → 2)-linked 4-O-methyl-α-D-glucuronic acid and (1 → 3)-linked α-L-arabinofuranose residues, both attached directly to a linear framework of (1 → 4)-linked β-D-xylose residues. The galactoglucomannans ([Formula: see text] 76 and 95) contained (1 → 6)-linked α-D-galactopyranosyl residues attached directly to a backbone of (1 → 4)-linked β-D-mannose and β-D-glucose residues. Partial hydrolysis of the two hexosans yielded 10 and 13 oligosaccharides, respectively, containing (1 → 4)-β-D-mannose, (1 → 4)-β-D-glucose, and (1 → 6)-α-D-galactopyranose residues. The molecular rotations of a series of mannooligosaccharides corresponded to a value of −54° for the specific rotation of an infinitely long mannan. It is concluded that the main hemicelluloses in amabilis fir wood are the same as those occurring in the wood of gymnosperms from other genera. The same three hemicelluloses are also present in the bark of this species.


1964 ◽  
Vol 42 (12) ◽  
pp. 2862-2871 ◽  
Author(s):  
F. Blank ◽  
M. B. Perry

The water-soluble polysaccharide preparation from Trichophytoninterdigitale was fractionated to give two distinct galactomannans and a glucan. A galactomannan isolated via its insoluble copper complex had [α]D +75° (water) and was composed of D-galactose (12%) and D-mannose (88%). On periodate oxidation, the galactomannan consumed 1.73 mole periodate and released 0.67 mole formic acid and 0.12 mole formaldehyde per anhydrohexose unit. Hydrolysis of the methylated galactomannan gave 2,3,5,6-tetra-O-methyl-D-galactose (1 part), 2,3,4,6-tetra-O-methyl-D-mannose (1 part), 2,3,4-tri-O-methyl-D-mannose (4 parts), and3,4-di-O-methyl-D-mannose (2 parts). Mild acid hydrolysis of the galactomannan removed all the galactose residues, leaving a mannan having [α]D +84° (water) whose structure was analyzed by periodate oxidation and methylation techniques.


1960 ◽  
Vol 38 (2) ◽  
pp. 280-293 ◽  
Author(s):  
G. A. Adams

A water-soluble polysaccharide containing L-arabinose and D-galactose in a molar ratio 1:3.8 was isolated from tamarack. Fractionation with ethanol from aqueous solution yielded one main component which was judged to be homogeneous on the basis of electrophoresis and sedimentation data. Hydrolysis of the fully methylated polysaccharide yielded, 2,3,5-tri-O-methyl-L-arabinose (2 moles); 2,3,4,6-tetra-O-methyl-D-galactose (16 moles); 2,5-di-O-methyl-L-arabinose (5 moles); 2,3,4-tri-O-methyl-L-arabinose (5.5 moles); 2,3,4-tri-O-methyl-D-galactose (11 moles); 2,4,6-tri-O-methyl-D-galactose (3 moles); 2,6-di-O-methyl-D-galactose (1 mole); 2,4-di-O-methyl-D-galactose (20 moles); 2-O-methyl-D-galactose (3 moles).Possible structures for the arabogalactan are proposed and discussed on the basis of these results.


1963 ◽  
Vol 41 (11) ◽  
pp. 2844-2848 ◽  
Author(s):  
N. Banerji ◽  
C. V. N. Rao

The polysaccharide extracted by 4% sodium hydroxide solution from pea skin (Pisum sativum) was shown to be composed of D-xylose and L-arabinose in a ratio of 5:1. Hydrolysis of the fully methylated arabinoxylan yielded 2,3,5-tri-O-methyl-L-arabinose, 2,3-di-O-methyl-D-xylose, and 2-O-methyl-D-xylose in the molar ratio of 1:4.2:1.1 and traces of 2,3,4-tri-O-methyl-D-xylose and D-xylose. From these results and those of periodate oxidation studies, a structural formula for the arabinoxylan has been proposed.


1962 ◽  
Vol 40 (6) ◽  
pp. 1196-1200 ◽  
Author(s):  
G. G. S. Dutton ◽  
A. M. Unrau

Only D-glucose was obtained on acid hydrolysis of the glucan. Periodate oxidation released formaldehyde, which was believed to arise from C6 of D-glucofuranose units. From the additional formaldehyde liberated from the borohydride-reduced glucan the degree of polymerization was estimated to be about 165. Complete hydrolysis of the derived polyalcohol gave glycerol, erythritol, D-glucose, and D-xylose. Partial hydrolysis gave glycerol, erythritol, and at least seven non-reducing oligosaccharides. Direct evidence for the existence of relatively large numbers of 1 → 6 and 1 → 4 linkages was found, together with smaller numbers of 1 → 2 linkages. The methylated glucan was freely soluble in chloroform – petroleum ether (5:95), and hydrolysis gave tetra, tri, di, and mono-O-methyl-D-glucoses in a 6:6:3:1 molar ratio.


1983 ◽  
Vol 48 (7) ◽  
pp. 2082-2087 ◽  
Author(s):  
Alžbeta Kardošová ◽  
Jozef Rosík ◽  
Rudolf Toman ◽  
Peter Capek

A water-soluble low-molecular D-glucan was isolated from leaves of the medicinal plant marsh-mallow (Althaea officinalis L.). The results of methylation analysis, partial hydrolysis, periodate oxidation, and 13C NMR data indicated a virtually linear structure with α-(1→6) glycosidic bonds.


1961 ◽  
Vol 39 (2) ◽  
pp. 375-381 ◽  
Author(s):  
C. V. N. Rao ◽  
D. Choudhury ◽  
P. Bagchi

A water-soluble polysaccharide isolated from the kernel of coconut (Cocos nucifera) had [α]D −85° and contained D-galactose (1 mole) and D-mannose (2 moles). Methylation and hydrolysis yielded 2,3,4,6-tetra-O-methyl-D-mannose (0.51 mole); 2,3,4,6-tetra-O-methyl-D-galactose (0.5 mole); 2,3,6-tri-O-methyl-D-mannose (5.52 moles); 2,3,6-tri-O-methyl-D-galactose (1.51 moles); and a di-O-methyl-D-galactose (1 mole). These data agree with those of periodate oxidation. The structural significance of these results is discussed.


1965 ◽  
Vol 43 (1) ◽  
pp. 30-39 ◽  
Author(s):  
C. T. Bishop ◽  
M. B. Perry ◽  
F. Blank ◽  
F. P. Cooper

A group of polysaccharides, called galactomannans I, were precipitated as their insoluble copper complexes from aqueous solutions of the crude polysaccharides obtained from each of the organisms designated in the title. The five galactomannans I were homogeneous under conditions of electrophoresis and ultracentrifugation and had high positive specific rotations. The major constituent monosaccharide was D-mannose; amounts of D-galactose ranged from nil for the polysaccharide from T. rubrum to 13% for that from T. schönleinii. Methylation and hydrolysis of the five galactomannans I yielded varying amounts of the following: 2,3,5,6-tetra-O-methyl-D-galactose (not present in the products from T. rubrum), 2,3,4,6-tetra-O-methyl-D-mannose, 2,3,4-tri-O-methyl-D-mannose, 2,4,6-tri-O-methyl-D-mannose, 3,4-di-O-methyl-D-mannose, and 3,5-di-O-methyl-D-mannose. Periodate oxidation results agreed with the methylation studies. The gross structural features of each galactomannan I appear to be the same, namely, a basic chain of 1 → 6 linked α-D-mannopyranose units for approximately every 22 of which there is a 1 → 3 linked α-D-mannopyranose residue. Branch points occur along the 1 → 6 linked chain at the C2 positions of the D-mannopyranose units and once in every 45 units at the C2 position of a 1 → 6 linked D-mannofuranose residue. The D-galactose in the polysaccharides is present exclusively as non-reducing terminal furanose units; non-reducing terminal units of D-mannopyranose are also present. The variations in the identities and relative amounts of the non-reducing terminal units were the only apparent differences in the gross structural features within this group of polysaccharides.


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