Galactomannan from the seeds of chinese honey locust (Gleditsia sinensis Lam.)

By the hot water extraction method, galactomannan was extracted (4.5% yield of the seed mass) from the seeds of Chinese honey locust (Gleditsia sinensis Lam). It had a molecular weight of 1230 kDa, and its solutions had a high viscosity [η] of 1064 ml/g and optical activity [α]_D of +21.4°. The polysaccharide consists of mannose and galactose residues in the molar ratio 2.69: 1. In the galactomannan macromolecule the backbone is formed by 1,4-β-D-mannopyranose residues, 37% of which are substituted by α-D-galactopyranose at C6. By ¹³C-NMR-spectroscopy, fragments of differently galactose-substituted mannobiose units were found to be in the galactomannan being studied: Man-Man, (Gal)Man-Man, and Man-Man(Gal) in the ratio of 0.23: 0.47: 0.30.