Chemical characterization and anti-obesity activity of exopolysaccharide isolated from Scleroderma areolatum Ehrenb

Two polysaccharide fractions were successfully isolated from the crude exopolysaccharide (EPS) of Scleroderma areolatum via gel filtration chromatography. Size exclusion chromatography/multi-angle laser light scattering (SEC/MALLS) analysis showed that the weight of average molecular weights (Mw) of these fractions was 3.162 ȕ 106 (Fr-I) and 2.613 ȕ 106 (Fr-II). Both EPS fractions exhibited a compact globular structure in aqueous solution. Monosaccharide composition analysis revealed that they were primarily composed of mannose and glucuronic acid. FT-IR spectral analysis identified prominent functional groups, such as hydroxyl and carboxylic, typical of heteropolysaccharides. When administered as supplements in high-fat diets to obese rats for 8 weeks, the EPS fractions reduced body weight, serum inflammatory factor levels, and significantly regulated serum lipid levels. Additionally, they increased the total concentration of short-chain fatty acids (SCFA) in colonic digesta. These results suggest a potential role for EPS in mitigating obesity and related metabolic disorders in high-fat diet-induced obese rats.