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

A water-soluble polysaccharide, extracted from the seeds of Leucaena l eucocephala 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 galactoma nnan was hydrolyzed, then converted into the alditol acetates. As a re sult of analyses of partially methylated alditol acetates by GC-MS (ga s chromatography-mass spectrometry), 1,5-di-O-acetyl-2,3,4,6-tetra-O-m ethyl-D-mannitol, 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 f rom alpha-galactosidase treatment, GC, IR (infrared), TLC (thin-layer chromatography), and GC-MS, the galactomannan had a beta-(1-->4) linke d D-mannan backbone bearing alpha-(1-->6) linked D-galactose side chai ns.