A non-ionic glucomannan from the seeds of an indigenous medicinal plant: Bryonia lacinosa

Extraction of defatted and decolorized seeds of Bryonia lacinosa with 1% aqueous acetic acid yielded a polysaccharide material, having d-glucose and d-mannose in the molar ratio of 1.00:1.01. Hydrolysis of the fully methylated seed gum furnished 2,3,4,6-tetra-O-methyl-d-glucose and 2,3-di-O-methyl-d-mannose in equimolar ratio. Partial hydrolysis of the polysaccharide furnished three oligosaccharides namely; epigentiobiose, mannobiose, and mannotriose along with the component monosaccharides. Periodate oxidation indicated about 49.75% of the end groups in the seed gum, which was in close agreement with the end groups calculated from methylation analysis, i.e. 49.55%. basis of the above results, a structure for the repeating unit of the polysaccharide has been proposed in which the main chain consists of β (1→4) linked mannopyranosyl units to which d-glucopyranosyl units are linked by α (1→6) linkages.