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Alginate is a linear and acidic polysaccharide, composed of (1 → 4) linked β- d -mannuronic acid (ManA) and α- l -guluronic acid (GulA). The ratio of ManA to GulA ( M / G ) is one of the most important factors for the application of alginate and its derivatives in various areas. In this work, a robust and accurate method was developed to analyze M / G using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). The impact of hydrolysis conditions on the release patterns of ManA and GulA from alginate and its derivatives was investigated. The release patterns of ManA and GulA need to be considered separately to obtain an accurate M / G . Several hydrolysis conditions were established that released ManA and GulA completely and maintained these saccharide residues intact. The proper M / G of alginates from different sources and its derivatives could then be calculated by integration of the corresponding ManA and GulA peaks. [ABSTRACT FROM AUTHOR]

Low-molecular-weight polyguluronate sulfate (LPGS) was prepared as a heparinoid by chemical sulfation of polyguluronic acid (PG), which was isolated from the hydrolysate of alginate by pH-fractionated precipitation. The structure of LPGS was elucidated based on FT-IR and 2D NMR spectroscopy. Sulfation was demonstrated to occur at the C-2 and C-3 positions of the guluronic acid residues and the degree of substitution (DS) was 1.53 per monosaccharide residue. The weight-averaged molecular weight of LPGS was 11.4kDa determined by high performance gel permeation chromatography (HPGPC). The in vitro anticoagulant activity and in vivo anti-inflammatory activity of LPGS were evaluated. Results showed that LPGS significantly prolonged the whole blood clotting time and activated partial thrombinplastin time (APTT), and exhibited considerable anti-inflammatory activity in cotton pellet-induced granuloma in rats. [Copyright &y& Elsevier]