Steviol Glycosides Modulate Glucose Transport in Different Cell Types

Abstract

Extracts fromStevia rebaudianaBertoni, a plant native to Central and South America, have been used as a sweetener since ancient times. Currently,Steviaextracts are largely used as a noncaloric high-potency biosweetener alternative to sugar, due to the growing incidence of type 2 diabetes mellitus, obesity, and metabolic disorders worldwide. Despite the large number of studies onSteviaand steviol glycosidesin vivo, little is reported concerning the cellular and molecular mechanisms underpinning the beneficial effects on human health. The effect of four commercialSteviaextracts on glucose transport activity was evaluated in HL-60 human leukaemia and in SH-SY5Y human neuroblastoma cells. The extracts were able to enhance glucose uptake in both cellular lines, as efficiently as insulin. Our data suggest that steviol glycosides could act by modulating GLUT translocation through the PI3K/Akt pathway since treatments with both insulin andSteviaextracts increased the phosphorylation of PI3K and Akt. Furthermore,Steviaextracts were able to revert the effect of the reduction of glucose uptake caused by methylglyoxal, an inhibitor of the insulin receptor/PI3K/Akt pathway. These results corroborate the hypothesis thatSteviaextracts could mimic insulin effects modulating PI3K/Akt pathway.