Structural characterization and anti-obesity effect of a novel water-soluble galactomannan isolated from Eurotium cristatum

Obesity is a serious public health challenge worldwide, the present study is aimed to investigate the structural characteristic and anti-obesity effect of a water-soluble galactomannan (PEC) extracted from Eurotium cristatum (E. cristatum). Detailed analysis of the PEC structure showed a weight-average molecular weight of 32,305 Da and a composition of mainly mannose, galactose and small amounts of glucose. Nuclear magnetic resonance spectroscopy combined with methylation analysis indicated that the main chain of PEC is →5)-β-D-Galf-(1 → 6)-α-D-Manp-(1 → glycosidic bond, and the branched chain →2)-α-D-Manp-(1 → through →2,6)-α-D-Manp-(1 → is connected to the main chain by an O-2 bond. Furthermore, PEC was found to ameliorate body weight gain, metabolic disorders, and to modulate the gut microbiota in HFD-fed mice. Fecal microbiota transplantation trial confirmed that PEC prevented obesity development and metabolic disorders by reversing gut dysbiosis in HFD-fed mice. This is the first report of the isolation of PEC from E. cristatum, and the findings suggested that PEC exerted its antiobesity and related beneficial effects by regulating the gut microbiota. In conclusion, as a polysaccharide, PEC could reduce obesity by modulating the gut microbiota and has potential been a prophylactic agent for obesity and related metabolic diseases.