Structure And Immunobiological Activity Of A Water-soluble Polysaccharide From The Boat-fruited Sterculia Seeds

Boat-fruited sterculia seeds(Semen Sterculiae Lychnophorae)is a tropical herb of the Sterculiaceae family.This plant is commonly used for the treatment of many diseases such as clearing phlegm (by''clearing heat from the lungs''as explained in Chinese medicine), relieving sore throat to restore the voice on the upper respiratory tract, and relaxing the bowels to relieve constipation.Water-soluble polysaccharides(SSLI) were isolated from boat-fruited sterculia seeds by hot water extraction and ethanol precipitation.Homogeneity and molecular weight of SSL were determined by gecolumn chromatography and High Performance Liquid Chromatography(HPLC).The result showed that SSL was a homogeneous polysaccharide with a molecular weight 466kDa.The structure of SSL was elucidated by periodate oxidation,Smith degradation and methylation analysis analysis.These analyse indicated that SSL has the following structure:(1→4)-linked-Gal(14.7%),(1→3)- linked-Ara (14.5%),(1→3)- linked -Rha(7.8%),(1→4,6)-linked- Gal(27.7),an terminal(1→)-linked–Rha(35.2%).Immunobilological activity assay showed that SSL could increase the ConA–indu- ced lymphocytes proliferation in vitro.