Structural characterization and effects on carbohydrate and lipid metabolism of a novel marine exopolysaccharide from P. sclerotiorum isolated in the south china sea

A novel polysaccharide, designated PS1–1, was isolated from the marine fungus P. sclerotiorum , which was obtained from a sponge found in the Xisha Islands of the South China Sea. PS1–1 was a heteropolysaccharide with a molecular weight of 7.66 kDa, and consisting of mannose, galactose, and a small amount of glucose in an approximate ratio of 8.35:2.07:1.0. Structural characterization via methylation analysis and NMR spectroscopy revealed that PS1–1 (7.66 kDa) consists of a backbone of →6)-α-D-Man p -(1 → and →2)-α-D-Man p -(1→, with side chains of →2)-β-D-Gal f -(1→, →2)-α-D-Man p -(1→, and α-D-Glc p -(1→), composed of mannose, galactose, and glucose in a ratio of 8.35:2.07:1.0. In high-fat diet and STZ-induced type 2 diabetic mice, PS1–1 significantly reduced fasting blood glucose, improved glucose tolerance, and alleviated insulin resistance (decreased HOMA-IR by 59.28 % in the high-dose group). It also ameliorated dyslipidemia (reducing TG, TC, LDL-C by 54–57 %) and oxidative stress (increasing SOD activity and T-AOC). These findings suggest that PS1–1 possesses promising therapeutic potential for the management of type 2 diabetes and may offer a basis for further development in diabetes treatment.