The composition of the proteinaceous polysaccharides exuded by astragalus microcephalus,A. Gummifer and A. Kurdicus—The sources of turkish gum tragacanth

Gum tragacanth is a variable commodity because commercial samples may legitimately be admixtures, in any relative proportions, of the exudates from Asiatic Astragalus spp. Analytical data show that the exudates collected from the three major contributing Turkish spp., A. microcephalus, A. gummifer and A. kurdicus, differ extensively, particularly in terms of their fucose, xylose, galacturonic acid and methoxyl contents and in the relative proportions of their soluble (tragacanthin) and insoluble (bassorin) components. In addition, these three Astragalus exudates are shown to be proteinaceous polysaccharides; their amino acid compositions differ, particularly in terms of their hydroxyproline, histidine, aspartic acid and arginine content. In contrast, the amino acid compositions of the soluble and insoluble components of A. kurdicus do not differ extensively.