Search

Fucoidans are complex sulfated polysaccharides extracted from brown algae. Depending on the concentration, they have been shown to stimulate and inhibit blood coagulation in vitro . Promotion of coagulation is mediated by blocking tissue factor pathway inhibitor (TFPI). We screened fucoidan extracts from four brown algae species in vitro with respect to their potential to improve coagulation in bleeding disorders. The fucoidans’ pro- and anticoagulant activities were assessed by global hemostatic and standard clotting assays. Results showed that fucoidans improved coagulation parameters. Some fucoidans also activated the contact pathway of coagulation, an undesired property reported for sulfated glycosaminoglycans. Chemical evaluation of fucoidans’ complex and variable structure included molecular weight ( Mw ), polydispersity (polyD), structural heterogeneity, and organic and inorganic impurities. Herewith, we describe a screening strategy that facilitates the identification of crude fucoidan extracts with desired biological and structural properties for improvement of compromised coagulation like in hemophilia. [ABSTRACT FROM AUTHOR]

Abstract: The sulfo groups of glycosaminoglycans contribute to their high charge densities, and are critical for the role they play in various physiological and pathophysiological processes. Unfortunately, the sulfo groups can be hydrolyzed to inorganic sulfate. Thus, it is important to monitor the presence of these sulfo groups. In addition, free anions, including chloride, sulfate and acetate, are often present in glycosaminoglycans as a result of multiple purification steps, and their presence also needs to be monitored. In this report, ion chromatography with conductivity detection is used to analyze the anions present in glycosaminoglycans, including heparin, heparan sulfate, chondroitin sulfate and dermatan sulfate. This method allows quantitation over a wide range of concentrations, affording a limit of quantitation of 0.1ppm and a limit of detection of 0.05ppm for most anions of interest. The stability of heparin was also studied, providing data on the formation of both sulfate and acetate anions. [Copyright &y& Elsevier]

Microcrystalline cellulose, a major component of cell wall of plants, is one of the most abundant natural materials, but the poor solubility of cellulose limits its applications. Cellulose is a linear glucan with exclusive β 1 → 4 linkage. Oxidation carried out with TEMPO–NaBr–NaClO system can selectively oxidize the C6 of glucose residues in cellulose. This modification improves polysaccharide solubility and other physicochemical properties. In this work, the impact of degree of oxidation on solubility, degree of crystallization, thermostability, molecular weight and the structures of the resulting oligosaccharide products of selectively oxidized cellulose were investigated using x-ray diffraction, thermogravimetric analysis, gel permeation chromatography–multiple angle laser light scattering and ultrahigh performance liquid chromatography–electrospray–quadrupole/time of flight–mass spectrometry, respectively. The physicochemical properties of selectively oxidized cellulose having different degrees of oxidation were carefully characterized providing a theoretical foundation for the more accurate selection of applications of oxidized celluloses. [ABSTRACT FROM AUTHOR]