Chemical, physico-chemical and cytotoxicity characterisation of xyloglucan from Guibourtia hymenifolia (Moric.) J. Leonard seeds

A water-soluble polysaccharide was obtained from Guibourtia hymenifolia seeds in a 54.2% yield (w/w). The Glc:Xyl:Gal molar ratio was 3.3:2.3:1. The methylation results and 1D/2D NMR spectra indicated the presence of xyloglucan (XG), the intrinsic viscosity of which was 665 mL/g. The molar mass (M(w)), radius of gyration (R(g)), hydrodynamic radius (R(h)), and rho (R(g)/R(h)) of XG were 8.43 x 10(5) g/mol, 97 nm, 61 nm, and 1.59, respectively, indicating a random coil and flexible conformation that was subsequently confirmed by the Mark-Houwink constant alpha (0.70). Atomic force microscopy analysis of XG adsorbed on silicon revealed that the chains are an average of 1.25-nm high, 28.9-nm wide and 131-nm long. Furthermore, a cytotoxicity assay indicated a high CC(50) value (>3.3 mg/mL). These results suggest that this biopolymer has potential applications in different food technologies and biotechnological processes. (C) 2010 Elsevier Ltd. All rights reserved.