The chemical structure of galactomannan isolated from seeds of Delonix regia.

A galactomannan isolated from seeds of Delonix regia was investigated. The specific rotation of the galactomannan was +15 degrees at 25 degrees C. The molecular mass of the galactomannnan was estimated to be 2.5 x 10(5). The ratio of D-mannose to D-galactose was estimated approximately to be 4.0:1.0 by HPLC and (1)H-NMR. NMR ((1)H and (13)C) spectra, and methylation analysis of the galactomannan indicated that it was composed of 1,4-linked beta-D-mannose, 1,4,6-linked beta-D-mannose, and terminal alpha-D-galactose. It was composed of pentasaccharide repeating-units, the chemical structure of which is proposed below.