Structural characterization and in vitro hypoglycemic activity of a glucan from Euryale ferox Salisb. seeds

In this research, a polysaccharide fraction (EFSP-1) was obtained from the seeds of Euryale ferox Salisb. by DEAE sepharose FF and Superdex^™ 75 gel chromatography. The average molecular weight (Mw) of EFSP-1 was 8.75 kDa. Monosaccharides composition analysis indicated that EFSP-1 was a glucan. The structure of EFSP-1 was characterized by analysis of FT-IR, GC-MS and NMR, which indicated that the backbone of EFSP-1 was mainly composed of (1→4)-α-D-Glcp with branches substituted at O-6 and terminated with T-α-D-Glcp. Moreover, the hypoglycemic effect of EFSP-1 was investigated by establishing insulin resistance HepG2 and 3T3-L1 cells. The results showed that EFSP-1 could increase glucose consumption by up-regulating the expression of GLUT-4 via activating PI3K/Akt signal pathway in IR cells. Hence, EFSP-1 could be a potential functional food to ameliorate insulin resistance for diabetes therapy.