WATER-SOLUBLE POLYSACCHARIDE FROM SEEDS OF TREES .1. GALACTOMANNAN FROM SEEDS OF LEUCAENA-LEUCOCEPHALA DE WIT

A water-soluble polysaccharide, extracted from the seeds of Leucaena leucocephala de Wit is composed of D-galactose and D-mannose in a molar ratio of 2:3. The molecular weight of the galactomannan was estimated to be about 4.8x10(5) by gel chromatography. The methylated galactomannan was hydrolyzed, then converted into the alditol acetates. As a result of analyses of partially methylated alditol acetates by GC-MS (gas chromatography-mass spectrometry), 1,5-di-O-acetyl-2,3,4,6-tetra-O-methyl-D-mannitol, 1,5-di-O-acetyl-2,3,4,6-tetra-O-methyl-D-galactitol, 1, 4,5-tri-O-acetyl-2,3,6-tri-O-methyl-D-mannitol, and 1,1,5,6-tetra-O-acetyl-2,3-di-O-methyl-D-mannitol were identified. Based on the data from alpha-galactosidase treatment, GC, IR (infrared), TLC (thin-layer chromatography), and GC-MS, the galactomannan had a beta-(1-->4) linked D-mannan backbone bearing alpha-(1-->6) linked D-galactose side chains.