Isolation, purification and structural investigation of a water-soluble polysaccharide from Solanum lyratum Thunb

Polysaccharides, extracted from the herbs of Chinese natural Solanum lyratum Thunb (SLT), which is a traditional Chinese medicine with hot water and 0.04 M sodium hydroxide successively, were fractionated and purified by ion-exchange and gel-filtration chromatography. According to methylation, periodate oxidation, NMR spectroscopy, partial and graded acid and enzymic hydrolysis analysis, the results indicated the D-glucan to be linear and to contain both (1-->3)- and (1-->4)-linkages. The anomeric NMR and IR spectra measurements confirmed that the sugar residues were beta-glycosidically linked.