Studies on uronic acid materials : Part XXII. The composition of the gum from Acacia dprepanolobium harms ex sjösted

Abstract

The gum polysaccharide from Acacia drepanolobium is not completely watersoluble, and has been subjected to graded extractions giving Fractions A (cold-water soluble, 80%), B (salt-soluble, 8%), and C (a gel soluble in dilute alkali, 12%). Fraction A contains l-arabinose (52%), d-galactose (38%), l-rhamnose (1%), d-glucuronic acid (7%), and 4- O-methyl- d-glucuronic acid (2%). Fractions A, B, and C each contain four aldobiouronic acids, viz., 6- O-(β- d-glucopyranosyluronic acid)- d-galactose; 4- O-(α- d-glucopyranosyluronic acid)- d-galactose; 6- O-(4- O-methyl-β- d-glucopyranosyluronic acid)- d-galactose; and 4- O-(4- O-methyl-α- d-glucopyranosyluronic acid)- d-galactose. The analytical differences between fractions A, B, and C have been investigated, and the factors that may account for their physical differences are discussed.