STUDIES ON URONIC ACID MATERIALS .26. ALDOBIOURONIC ACIDS IN GUMS FROM ACACIA SPECIES

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. © 1968.