Studies on uronic acid materials: Part XXVI. The aldobiouronic acids in gums from acacia species

Abstract

Acacia seyal gum contains four aldobiouronic acids that have been characterised as 6- O-(β- D-glucopyranosyluronic acid)- D-galactose ( A), 4- O-(α- D-glucopyranosyluronic acid)- D-galactose ( B), 6- O-(4- O-methyl-β- D-glucopyranosyluronic acid)- D-galactose ( C), and 4- O-(4- O-methyl-α- D-glucopyranosyluronic acid)- D-galactose ( D). With these acids as chromatographic standards, the aldobiouronic acids present in a further seventeen species of Acacia gum have been investigated. Gums having positive rotations and significant methoxyl contents give aldobiouronic acids A- D, whereas gums having positive rotations and low methoxyl contents do not give significant proportions of acids C and D. Gums having negative rotations and significant methoxyl contents give acids A and C; one gum having a negative rotation and a low methoxyl content did not give a significant proportion of acid C.