Purification, Structural Characterization, and Anti-Inflammatory Effects of a Novel Polysaccharide Isolated from Orostachys fimbriata

The present study elucidated the structural characteristics and anti-inflammatory activity of a novel polysaccharide isolated from Orostachys fimbriata, which is a traditional Chinese medicinal plant. O. fimbriata polysaccharide (OFP) was extracted and subsequently purified by chromatography using a DEAE cellulose-52 and Sephadex G-75 column. The molecular weight was determined as 6.2 kDa. HPGPC and monosaccharide composition analysis revealed a homogeneous polysaccharide containing only Glc. Chromatography and spectral analysis showed that the possible chemical structure consisted of →4)-α-Glcp-(1→ and a small quantity of →4,6)-β-Glcp-(1→ in the main chain and →6)-β-Glcp-(1→, α-Glcp-(1→, and β-Glcp-(1→ in the side chain. Morphological analysis using scanning electron microscopy (SEM) and atomic force microscopy (AFM) indicated that OFP had a multi-branched structure, and the sugar chain molecules of polysaccharide appeared aggregated. OFP was found to exhibit anti-inflammatory activity by reducing the secretion of inflammatory factors in RAW264.7 cells and by decreasing the extent of xylene-induced ear swelling in mice.

Identification of an α-(1,4)-Glucan-Synthesizing Amylosucrase from Cellulomonas carboniz T26

Amylosucrase, catalyzing the synthesis of α-(1,4)-glucan from sucrose, has been widely studied and used in carbohydrate biotransformation because of its versatile activities. In this study, a novel amylosucrase was characterized from Cellulomonas carboniz T26. The recombinant enzyme was overexpressed in Escherchia coli and purified by nickel affinity chromatography. It was determined to be a monomeric protein with a molecular mass of 72 kDa. The optimum pH and temperature for transglucosylation were measured to be pH 7.0 and 40 °C. The transglucosylation activity was significantly higher than the hydrolytic activity. The main product generated from sucrose was structurally determined to be α-(1,4)-glucan. A small amount of glucose was produced by hydrolysis, and sucrose isomers including turanose and trehalulose were generated as minor products. The ratio of hydrolytic, polymerization, and isomerization reactions was calculated to be 5.8:84.0:10.2. The enzyme favored production of long-chain insoluble α-glucan at lower temperature.