Plant mucilages. XXXI. An acety-rich mucous polysaccharide, "lycoris-R-glucomannan," from the bulbs of Lycoris radiata.

Abstract

A mucous polysaccharide, named Lycoris-R-glucomannan, was isolated from the bulbs of Lycoris radiata HERBERT. 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 12 : 1, and its molecular weight was estimated to be 468000. O-Acetyl groups were identified in the glucomannan and their content amounted to 15.5%. They were located at positions 2, 6 of some of the D-mannose units. Methylation, periodate oxidation, and partial acid hydrolysis studies showed that the glucomannan is mainly composed of β-1→4 linked aldohexopyranose residues, and that it contains about thirteen aldohexose units per three non-reducing groups on average. D-Mannose units occupy non-reducing terminal positions and branching points linked through both positions 3 and 6.