The water-soluble polysaccharide extracted from the Icernel of green palmyra palm nut ( B o~a s s ?~s flabellifer Linn.) was shown to be composed of D-galactose and D-lnannose in the proportion of 1:2.4. Hydrolysis of the fully methylated galactomannan yielded 2,3,4,6-tetra-0-methyl-D-galactose, 2,3,6-tri-0-methyl-~-mannose, and 2,3-di-O-lnethyl-~-1mnose in the molar ratio of 1:1.4:0.95. Partial hydrolysis of the galactomannan afforded 4-0-8-D-mannopyranosyl-D-mannose, 6-O-ol-~-ga~actopyranosy~-~-111i~111lose, and two trisaccharides. Based on these r e s~~l t s a struct~lral formula for the galactomannan has been proposed, additional evidence for which was adduced from periodate-oxidation studies. I11 1956 Subrahmanyan et al. (1) reported the isolation of a polysaccharide from the kernel by extraction with 10% sodiuin hydroxide which gave, on hydrolysis, D-galactose and D-mannose in the ratio of 1 :2.9 approxinlately. I-Iowever, no detailed investigations seen1 to have been carried out on its structure. This paper reports the structural studies on the polysaccharide obtained by precipitating the aqueous extract of the soft kernel with ethanol. Hydrolysis of the polysaccharide, [aID3O +8.5" (in 4% sodium hydroxide solution) gave D-galactose and D-mannose in the molar proportion of 1:2.4 as estimated by the periodate method (2).The galactomannan \vas methylated first by repeated treatment with methyl sulphate and alkali (3) and then by Purdie's method (4). The resulting methylated galactomannan, which showed no hydroxyl absorption band in the I.R. spectrum, was a glassy solid -0CHs 43.25y0, ++2 (in chloroform). After methanolysis of the inethylated polysaccharide and hydrolysis of the resulting nlixture of inethyl glycosides the mixture of methyl sugars, so obtained, on paper chronlatographic exanlination using solvents B and D showed the presence of three methylated sugars together with a trace amount of another. The mixture of methylated sugars was separated on a cellulose column (5) using butanone-water azeotrope (6) as eluent. Identification of the various ~nethylated sugars obtained by c o l u i~~n chromatography showed them to be 2,3,4,6-tetra-0-methyl-~-galactose (1 mole), 2,3,6-tri-0-methyl-Dmannose (1.35 moles), 2,3,6-tri-0-methyl-D-galactose (0.035 mole), and 2,3-di-0-methyl-D-mannose (1.03 moles).The relative proportion of 2,3,4,6-tetra-0-methyl-D-galactose, 2,3,6-tri-O-n1ethyl-Dmannose, and 2,3-di-0-methyl-D-mannose mas estimated by hypoiodite titration (7) after separation on paper using solvent B and was found to be 1:1.4:0.05. This ratio is in good agreement with that obtained by weighing the different fractions obtained during column chromatographic examination of the mixture. The tetra-0-methyl sugar fraction, [a]," +log0 (in water) obtained as a sirup, gave on demethylation (8) D-galactose only along with some partially demethylated sugars and was characterized to be 2,3,4,6-tetra-0-methyl-D-galactose through its anilide (9).The tri-0-methyl-D-mannose [ a I D 3 O -9' (in water) was chara...
