Polysaccharides from Sutherlandia frutescences leaves have immunomodulating properties

Sutherlandia frutescens, syn. Lessertia frutescens, is a plant of long traditional use in South Africa, and over the last years it has obtained great interest as a plant that has positive effects in relation to the treatment of HIV/AIDS.

Patients having HIV/AIDS have often a low immune response. If this can be stimulated the wellbeing of the person will increase. As polysaccharides have been shown to have immunomodulating properties [1,2,3] it was of interest for us to study polysaccharides from the leaves of Sutherlandia frutescens and focus on their structure and effect in immunoassays related to the immune system.

Traditionally, water extracts have been the choice of preparation of remedies used. For this reason we prepared water extracts, and from these purified polysaccharides both of the xylan type and of the pectin type were prepared. Determination of their monosaccharide compositions as well as their linkages showed that the xylan mainly was 1,4 linked, while the pectins contained typical rhamnogalacturonan type I regions as well as sidechains containing arabinogalactan type II structures. The polysaccharides had a marked effect in the complement system and did also show proliferation of B cells and maturation of dendritic cells, all effects indicating immunomodulating properties.

References: [1] Paulsen, B.S., Barsett, H. (2005) Advances in Polymer Science, Bioactive pectic polysaccharides (Polysaccharides I) Springer Berlin/Heidelberg, Germany, pp69–101.

[2] Inngjerdingen, K.T. et al. (2007) Glycobiology 17(12):1299–1310.

[3] Inngjerdingen, M. (2008) Glycobiology 18(12):1074–1084.