Structural characterization and immunostimulatory properties of a type II arabinogalactan extracted from St. John's wort

The goal of this research was to extract polysaccharides from the cell walls of wild type St. John's wort plants in order to structurally characterize them through the use of various techniques. Composition, linkage and sequence analyses were completed to attempt to determine the three dimensional structure of the extracted intact polysaccharide through the use of gas chromatography-mass spectrometry (GC-MS), electrospray-mass spectrometry (ES-MS), and nuclear magnetic resonance (NMR). Since this polysaccharide was extremely large several chemical degradations including Smith degradation and partial hydrolysis were used to break the intact polysaccharide into smaller fragments for continued analysis. Composition, linkage and sequence analyses were then repeated on the smaller fragments of the extracted polysaccharide which revealed a great deal of information. Evidence was obtained that the extracted polysaccharide from the leaves of St. John's wort plants is a type II arabinogalactan which may be attached to a type I rhamnogalacturonan. Preliminary experiments indicate that the intact polysaccharide exhibits bioactive properties and is suggested to be an immunostimulant in mammals.