Bioactive pectic polysaccharides

Polysaccharides from plants have been the subject of studies for a very long time, mainly focussed on their physical properties, their chemical and physical modification, and their application. Over the last 20 years there has been increasing interest in the biological activity of the natural polysaccharide polymers. These studies became possible as a result of the scientific development of isolation, purification and characterisation methods concomitant with the development of fairly simple in vitro tests for effects especially on the immune system. The growing acceptance of the knowledge to be gained by people still using so-called traditional medicine in finding sources worthy of study has led to new sources for interesting bioactive plant polysaccharides. This chapter contains only the knowledge on bioactive plant polysaccharides of the pectic type gained over approximately the last ten years and the focus is on those papers where structural characterisation has been performed. For this reason, the reader may not find all of the plants studied during this period within the chapter. Discussions concerning the structural aspects of polysaccharides that may be responsible for activity, are included where relevant.