Preparation of low-molecular-weight polyguluronate sulfate and its anticoagulant and anti-inflammatory activities

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 11.4 kDa 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.