EXTRACTION ET PURIFICATION DES GALACTOMANNANES A PARTIR DES GRAINES DE Gleditsia triacanthos L.

Abstract

The albumen of Gleditsia triacanthos fruit, a plant native to eastern and central United States, contains a water-soluble galactomannan. It has been suggested that this polysaccharide is a substitute for guar gum in food applications or as a therapeutic agent in medical applications for reducing the toxicity of anticancer agents. Pure extracts are obtained from the fruit seeds harvested in the region of Annaba (Algeria). This purification was carried out by the Fehling liquor which allows the fractionation of the polysaccharides by precipitation of the insoluble Cu2+-galactomannan complex. This precipitate is regenerated by treatment with a solution containing HCl 5% in ethanol 96%. The oses composition of the polysaccharide was determined, after acid hydrolysis, by thin layer chromatography in the solvent: ethyl acetate / isopropanol / water (65:23:12). The polymers chemical modification techniques have allowed access to a new class of homogeneous derivatives with very promising properties. In addition to sulfation techniques using dimethylsulfoxide complexes: sulfur trioxide (DMSO: SO3) or dimethylformamide: sulfur trioxide (DMF: SO3), it is envisaged to use the heterogeneous phase catalysis methods which could allow to obtain a sulfated galactomannan of controlled degree of polymerization.