Motohiro Nishijima

Structure of a heteroglycan isolated from the fungus Omphalia lapidescens

The major, water-soluble polysaccharide isolated from the sclerotia of Omphalia lapidescens, and purified by chromatography on DEAE-Sephadex A-50 and Toyopearl HW-65F, is a heteroglycan (OL-3), [alpha]D20 - 50 degrees (c 1, water), which is composed of D-glucose, 2-acetamido-2-deoxy-D-glucose, and D-glucuronic acid in the molar ratios 1.21:1.00:1.38. Methylation analysis, partial acid hydrolysis, and f.a.b.-m.s. of the hydrolysates indicated OL-3 to have a highly branched structure involving (1----3)-, (1----4)-, (1----6)-, and (1----3,6)-linked, and non-reducing terminal D-glucopyranosyl residues, and also to contain 2 acetamido-2-deoxy-beta-D-glucopyranosyl-(1----4)-beta-D- glucopyranosyluronic acid and beta-D-glucopyranosyl-(1----4)-2-acetamido-2-deoxy-beta-D-glucopyranosyl -(1----4)-beta-D-glucopyranosyluronic acid segments.

A novel glycosaminoglycan from the fungus Omphalia lapidescence

Abstract The major, water-soluble polysaccharide isolated from the sclerotia of Omphalia lapidescence, and purified by chromatography on DEAE-cellulose and zone electrophoresis, is a heteroglycan (OL-1), (c 1, water), which is composed of d -glucose, 2-acetamido-2-deoxy- d -glucose, and d -glucuronic acid in the molar ratios 1.0:1.95:2.0. The results of periodate oxidation, Smith degradation, and methylation analysis showed that the polysaccharide has a highly branched structure involving 1,3-, 1,4-, 1,6-, and 1,3,6-linked d -glucopyranosyl, 1,3,4-linked 2-acetamido-2-deoxy- d -glucopyranosyl, and (1,3 ?)- and 1,4-linked d -glucopyranosyluronic acid residues. The non-reducing terminal positions are occupied by the three component sugars. The branched glycosaminoglycan OL-1 is the first to be found in the fungi.

Determination of Isopropyl Citrate in Edible Oil

An analytical method was developed for the determination of isopropyl citrate in edible oil.The sample was dissolved in ethyl acetate and mono- and diisopropyl citrate were extracted with 5% sodium bicarbonate. The aqueous layer was acidified with phosphoric acid and isopropyl citrates were extracted with ethyl acetate. The ethyl acetate layer was dried with anhydrous sodium sulfate and evaporated to dryness. The residue was fluorescence-labeled with 4-bromomethyl-7-methoxycoumarin (Br-Mmc). Thin layer chromatography was used for the qualitative determination of fluorescence-labeled mono- and diisopropyl citrates.Qualitative determination was carried out as follows. The sample was hydrolyzed with potassium hydroxide solution. The hydrolyzed solution was washed with hexane and applied to the Amberlite IRA-402 column. Citric acid was eluted with 1N hydrochloric acid. The eluate was evaporated to dryness, and the residue was dissolved in water. High performance liquid chromatography was used for quantitative determination of citric acid.The recoveries of isopropyl citrates added to edible oil were in the range from 84% to 93% and the detection limit of monoisopropyl citrate was 5μg/g.