Hypoglycemic effects of polysaccharides from corn silk (Maydis stigma) and their beneficial roles via regulating the PI3K/Akt signaling pathway in L6 skeletal muscle myotubes

Abstract

In the present study, the physicochemical properties of polysaccharides from corn silk (CSP) with different molecular weights were characterized and their inhibitory actions against α-glucosidase and α-amylase were evaluated. Then their effects on glucose uptake and mechanism of action in PI3K/Akt signaling pathway were also determined in L6 skeletal muscle cells. Results demonstrated that CSP could significantly inhibit α-amylase and α-glucosidase. CSP were non-toxic and they considerably increased the 2-NBDG uptake (P < 0.05) in L6 cells. Additionally, CSP regulated the PI3K/Akt signaling pathway and promoted the translocation of GLUT4 to the plasma membrane that would enhanced the glucose uptake in rat L6 skeletal muscle cells. Among the tested polysaccharides, CSP2 with the molecular weight of 62.16 kDa exerted appreciable hypoglycemic activity. Altogether it was suggested that CSP could be the promising candidate in the treatment of Type 2 Diabetes Mellitus (T2DM). The elucidation of the potential anti-diabetic mechanism of the polysaccharides from corn silk will facilitate their utilization in the functional food industries.

Keywords: Corn silk polysaccharides; Hypoglycemia; L6 myotubes; PI3K/Akt signaling pathway.