Polysaccharides ofEremurus. XV. Structure of the glucomannan ofEremurus lactiflorus

Ten oligosaccharides have been isolated from the products of the partial hydrolysis of a native acetylated glucomannan obtained fromEremurus lactiflorus O. Fedtsch. Their structures have been studied with the aid of acid hydrolysis before and after reduction with NaBH₄, by the GLC method, and also by chromatography with markers. The compositions and sequence of the monomers in tetra- and heptaoligo-saccharides have been determined by the¹³C NMR method. The glucommannan ofE. lactiflorus differs from theEremurus glucomannans studied previously by the ratio of monosaccharides, the presence of 0-Ac groups, the degree of polymerization, and the presence of a cellobiose unit (Glcp-Glcp) in the polymer chain. The repeating unit consists of 14 hexose residues.     

Polysaccharides ofEremurus. XI. Products of the oxidation and methylation of a glucomannan fromEremurus lactiflorus

It has been established by oxidation with chromium trioxide and sodium periodate and by methylation that the monosaccharide residues in the glucomannan ofEremurus lactiflorus O. Fed. are linked by -1 ; 4 bonds, and there is a mannose residue at the nonreducing end. The glucomannan macromolecule has a linear structure.Deceased.Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 767–770. November–December, 1980.     

Polysaccharides ofEremurus. X. Characteristics of the polysaccharides ofEremurus lactiflorus andE. luteus

Water-soluble polysaccharides have been isolated from two species ofEremurus — E. lactiflorus andE. luteus — with yields of 13.5% and 20.5%, respectively. They contained mainly glucose and mannose in ratios of 1:5 and 1:3.1. The polysaccharides ofE. lactiflorus were separated from a column of DEAE-cellulose. The yield of neutral fraction was 10.3%. Gel filtration of the polysaccharides on Sephadex G-200 showed their polydispersity. Homogeneous fractions were obtained by fractional precipitation with ethanol. They have been characterized with respect to monosaccharide composition, molecular weight, and IR spectra.     

Polysaccharides ofEremurus. XXIV. Pectin substances ofEremurus and dynamics of the accumulation of pectin inEremurus lactiflorus

Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 109–110, January–February, 1990.     

Polysaccharides ofEremurus. XXI. Pectin substances of the leaves ofEremurus regelii

The pectin substances have been isolated fromEremurus regelii Vved., their qualitative and quantitative monosaccharide compositions have been determined, and their physicochemical properties have been studied. The partial hydrolysis of the pectin gave a galacturonan. On the basis of the results of periodate-nitric acid oxidation, enzymatic hydrolysis, and methylation it has been shown that in the galacturoman the galacturonic acid residues are linked by -(1 4)-glycosidic bonds.Deceased.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 172–174, March–April, 1985.     

Polysaccharides ofPolygonatum. IV. A study of the structure of the glucomannan ofPolygonatum severzovii

The structure of the glucomannan established on the basis of the results of methylation, chromium trioxide oxidation of the acetylated glucomannan, and partial hydrolysis, is given. The partial hydrolysis of the glucomannan gave a series of oligosaccharides — 4-O-β-D-glucopyranosyl-D-mannopyranose, di-, tri-, and tetrasaccharides, and β-1→4-bound D-mannooligosaccharides — the structures of which follow from the results of hydrolysis, periodate oxidation, methylation, and mass spectrometry. A structure is proposed for the repeating unit.     

Polysaccharides ofEremurus. XIII. Study of the structure of the partially acetylated glucomannans by the13C NMR method

The¹³C spectra of the glucomannans fromEremurus lactiflorus andE. luteus are analyzed in comparison with the spectra of low-molecular-weight model compounds. It has been shown that the linear polymer chain consists of 1 → 4-bound glycosidic residues in the pyranose form, which confirms the results of earlier chemical investigations of these polysaccharides.