Abstract

In this study, we investigated the structural characterization and antidiabetic effects of Lactobacillus H31 exopolysaccharide (EPS) H31-2 from pickled cabbage. The BLAST result indicated that Lactobacillus H31 was closely related to L. plantarum S1S2L2. In the spectrum of Fourier-transform infrared spectroscopy (FT-IR), 3370 cm-1 was the characteristic band of polysaccharide. A structural analysis showed that the monosaccharides of EPS H31-2 included d-mannose (Man) and d-glucose (Glc). The molecular weight of EPS H31-2 was around 10.75 kDa. All these results suggested EPS H31-2 was a novel polysaccharide. The inhibition ratios of crude EPS H31 and the pure fraction H31-2 of pancreatic α-amylase were 89.10 ± 2.59% and 69.23 ± 8.95%, respectively. In addition, the supernatant glucose concentration of insulin-resistant HepG2 cells decreased by treatment with 10-8 M of EPS H31-2, which meant EPS H31-2 could promote the glucose uptake of insulin-resistant HepG2 cell. Furthermore, EPS H31-2 upregulated the expression of the GLUT-4, Akt-2, and AMPK, which play important roles in glycometabolism. These results suggested that L. plantarum EPS H31-2 could effectively inhibit the activity of pancreas α-amylase and has potential applications in the prevention and alleviation of diabetes mellitus.