Synthesis, immunological activities, and scavenging ability toward superoxide anion of (1→3)-β-d-pentaglucoside and its epoxyalkyl derivatives

Preparation, deproteinization, characterisation, and antioxidant activity of polysaccharide from cucumber (Cucumis saticus L.)

Preparation, deproteinization and antioxidant activity of polysaccharide from cucumber (Cucumis saticus L.) were investigated. The crude cucumber polysaccharide was extracted by hydrothermal method. It showed that the trichloroacetic acid (TCA) method had the higher deproteinization percentage, but a little higher polysaccharide loss percentage than the CaCl₂ method. The cucumber polysaccharide is linked by the β-glycosidic linkage. It consisted of d-glucose, d-mannose, d-galactose, l-rhamnose, d-xylose, l-arabinose, d-glucuronic acid, and d-galacturonic acid. Their mole ratio was 6.00:4.03:8.31:2.82:2.75:6.60:1.05:5.79. Moreover, it proved that the cucumber polysaccharide had high scavenging ability to superoxide anions.

Synthesis and stability assay of 4-methylumbelliferyl (1-->3)-beta-D-pentaglucoside

The synthesis and stability of 4-methylumbelliferyl (1 --> 3)-beta-D-pentaglucoside 3 are described. The (1 --> 3)-beta-D-glucan isolated from the cell walls of Saccharomyces cerevisiae was recovered from the aqueous medium as water-insoluble particles by the spray drying (GS) method. The acid-solubilized (1 --> 3)-beta-D-oligoglucosides were prepared by partial acid hydrolysis of glucan. The peracetylated (1 --> 3)-beta-D-pentaglucoside 1 was obtained by isolation of peracetylated (1 --> 3)-beta-D-oligoglucoside mixture. The peracetylated 4-methylumbelliferyl (1 --> 3)-beta-D-pentaglucoside 2 was synthesized by treating compound 1 with the 4-methylumbelliferone and a Lewis acid (SnCl4) catalyst. NaOMe in dry methanol was used for the deacetylation of the blocked derivative, to give the target compound 3 in an overall yield of 35%. Activity assays with beta-glucosidase indicated that compound 3 was much more stable than the corresponding pentasaccharide.