Chemical structure elucidation of an inulin-type fructan isolated from Lobelia chinensis lour with anti-obesity activity on diet-induced mice

A neutral polysaccharide (LCPS) was obtained from Lobelia chinensis via hot water extraction and ethanol precipitation. After separation and purification, the homogeneous polysaccharide was obtained with a molecular weight of 2.6 × 10³ Da. The chemical composition of the extracted polysaccharide contains fructose and glucose with protein-free identified by gas chromatography-mass spectrometer (GC-MS) method. Chemical structure of LCPS was indicated by nuclear magnetic resonance (NMR) spectroscopy. Data indicated that LCPS was an inulin-type fructan with α-D-Glcp-(1→[1)-β-D-Fruf-(2]₁₅ linkage. LCPS intake reduced at significant level high fat diet (HFD)-induced body weight gain, liver weight, total cholesterol and triglyceride in serum and hepatic tissue, respectively. The lipid droplet accumulation in hepatic tissue was similar between lean and LCPS groups lower than in HFD-induced mice from tissue section staining results. Together, polysaccharides from Lobelia chinensis could be a new source of natural anti-obesity agent against obesity with potential value in the manufacturing supplements and drugs.

Keywords: Lobelia chinensis Lour polysaccharides; anti-obesity; chemical structure; high fat diet-induced mice; inulin-type fructan.