Background: Many previous studies have reported the role of oat β-glucan (OBG) in the reduction of postprandial glucose, and hypothesised that OBG may form a protective layer along the intestinal wall, acting as a viscous barrier to decrease glucose transportation. This study examined whether the molecular weight (MW) and concentration of OBG affected the diffusion of glucose in vitro. The effect of OBG on glucose transportation in vitro and sodium-potassium adenosine triphosphatase (Na(+)/K(+)-ATPase) activity in the everted small intestines of normal rats was also examined.
Results: In vitro, higher MWs and concentrations of OBG increased the inhibitory effects on glucose diffusion and glucose adsorption. The transport of glucose by glucose transporters and Na(+)/K(+)-ATPase activity in the small intestinal mucosa of rats were significantly lower following the addition of OBG than those in the absence of OBG at the same time-points throughout glucose transportation (P < 0.05). In the OBG-treated group, the Na(+)/K(+)-ATPase activity decreased with increasing OBG MW. However, as the concentration of OBG in the solution increased, the Na(+)/K(+)-ATPase activity in the small intestine increased due to stronger gastrointestinal motility. We also found that higher MWs of OBG had a greater inhibitory effect on intestinal disaccharidase activities in vitro.
Conclusion: Oat β-glucan is able to adsorb glucose molecules, inhibit glucose transport, decrease the concentration of available glucose and suppress disaccharidase activities in the small intestine.
Keywords: Na+/K+-ATPase; disaccharidase; glucose adsorption; glucose transport; oat β-glucan.
© 2015 Society of Chemical Industry.