Preliminary Structural Characterization and Bioactivity of Exopolysaccharides Produced by Sanghuangporus vaninii...

Sanghuangporus vaninii produces bioactive polysaccharides with therapeutic potential, but the structural features and anti-obesity mechanisms of its exopolysaccharides (EPS) remain unclear. Two polysaccharide fractions (Fr-I and Fr-II) have been purified from the crude EPS of S. vaninii via gel filtration chromatography. The structural characterization of the two fractions was comprehensively characterized at multiple levels, employing SEC/MALLS, GC and FT-IR. SEC/MALLS indicated their average molecular weights (Mw) have been 3.162 ȕ 106 (Fr-I) and 2.613 ȕ 106 (Fr-II). Both fractions exhibited compact globular architectures when suspended in aqueous medium. GC demonstrated clearly, they mainly contained mannose and glucuronic acid, and FT-IR identified typical heteropolysaccharide functional groups. In vitro, Fr-II had better DPPH and OH radical scavenging activity. Furthermore, in rodent models of diet-induced obesity, EPS supplementation for 8 weeks helped counteract weight gain, led to a reduction in serum inflammatory factors, regulated serum lipids, and resulted in an elevation of colonic short-chain fatty acids (SCFA). Thus, the medicinal fungus S. vaninii EPS may represent a valuable prebiotic for obesity and related metabolic disorders.