Anti‐hyperglycemic Effect and Mode of Action of Palatinose In vitro and Animal Models

Abstract

Inhibition of α‐amylase and α‐glucosidase involved in the digestion carbohydrates can decrease the postprandial increase of blood glucose level after a mixed carbohydrate diet. In the course of screening these enzyme inhibitors, we screened isomaltulose (6‐0‐α‐D‐glucopyranosyl‐D‐fructose) using in‐vitro enzyme inhibition assay. Isomaltulose, known by the trade name Palatinose, is a disaccharide that is manufactured from sucrose via bacterial fermentation. Several studies showed that Palatinose had benefit effects on anti‐hyperglycemic effect in human clinical trials. However, there is limited information about the action mechanism on blood glucose lowering effect. Therefore, inhibitory activity of Palatinose against rat intestinal α‐glucosidases and porcine pancreatic α‐amylase were investigated in this study. The half‐maximal inhibitory concentration (IC50) of Palatinose on α‐amylase and α‐glucosidase were 30.8 and 91.8 mM, respectively. The postprandial blood glucose lowering effects of Palatinose was compared to a known type 2 diabetes drug (Acarbose), a strong α‐glucosidase inhibitor in the Sprague‐Dawley (SD) rat model. In rats fed on starch, the blood glucose level at 30 min after administration in Palatinose‐treated SD rats (0.1 g/kg‐body weight) was significantly lower than in untreated group (173.94 ± 10.15 vs. 195.80 ± 12.92 mg/dL, respectively). These results indicate that Palatinose may have anti‐hyperglycemic effect by suppressing carbohydrate absorption in the gastrointestinal level, and thereby reducing the postprandial increase of blood glucose.