Plant Mucilages. XXXV. Isolation and Characterization of a Mucous Polysaccharide, Hippeastrum-H-glucomannan, from the Bulbs of Hippeastrum hybridum

A mucous polysaccharide, named Hippeastrum-H-glucomannan, was isolated from the bulbs of Hippeastrum hybridum Hort. The final preparation was homogeneous as determined by ultracentrifugal analysis, glass-fiber electrophoresis, and gel chromatography. It was composed of D-mannose and D-glucose in the molar ratio of 5:2, and its molecular weight was estimated to be 331000. 0-Acetyl groups were identified and their content amounted to 13.2%. They were located at positions 2, 6 of some of the D-mannose units. Methylation and partial acid hydrolysis studies showed that the glucomannan is mainly composed of β-1 → 4–linked aldohexopyranose residues, and that it contains about eighty-three aldohexose units per six non-reducing groups on average. Both D-mannose and D-glucose units occupy non-reducing terminal positions and branching points linked through position 3.