Abstract
A new galactomannan has been isolated as a water soluble component from the defatted
seeds of Cassia nodosa. Fractional precipitation with ethanol, electrophoresis, displacement chromatography
and acetylation followed by deacetylation revealed the homogeneous nature of the polysaccharide.
Acid hydrolysis followed by separation of the hydrolyzate by paper partition chromatography
and subsequent estimation of the sugars by periodate oxidation method and also spectrophotometrically
using phenolsulphuric acid reagent revealed the presence of D–galactose and D–mannose
in the ratio of 1:3.5 in the galactomannan. Hyydrolysis of the methylated polysaccharide
yielded 2,3,4,6,tetra–O–methyl–D–galactose (1 mole), 2,3,6–tri–O–methyl–D–mannose
(2.5 moles) and 2,3–di–O–methyl–D–mannose (1 mole). Determination of the terminal
groups by periodate oxidation of the polysaccharide and subsequent titration of formic
acid liberated corresponds to 22.75 per cent which is in close agreement to that revealed
by methylation studies, 22.1 percent. The polysaccharide is branched and contains
α–linked D–galactopyranose end groups combined with 1,4– and 1,4,6–linked β–D–mannopyranose
units. Graded hydrolysis of the polysaccharide and sequential Chromatographie examination
of the hydrolyzate at various intervals indicated that galactose was the first sugar
released.
