Preparation, partial characterization and bioactivity of water-soluble polysaccharides from boat-fruited sterculia seeds

Crude water-soluble polysaccharides (SP) isolated from boat-fruited sterculia seeds by hot water extraction and ethanol precipitation were fractionated into a neutral polysaccharide (NSP) and an acidic one (ASP) by anion-exchange chromatography. The molecular weight, intrinsic viscosity and radius of gyration of NSP and ASP were determined by high performance size exclusion chromatography (HPSEC). NSP was rich in glucose (85.86%), with small amounts of galactose, arabinose and xylose. Whereas ASP consisted mainly of galacturonic acid (40.13%) along with rhamnose, arabinose, galactose, and small amounts of xylose and glucose, indicating a pectin-like polysaccharide which was confirmed by FT-IR spectra. Bioactivity of NSP and ASP was tested using ear edema induced by dimethylbenzene and cotton pellet-induced granuloma tissue in murine models. The results showed ASP possessed a potent dose-dependent anti-inflammatory activity. The results from the current study provided a scientific basis for the traditional use of this plant as a medical remedy for its anti-inflammation effects.