The entrocytes of the small intestine can only absorb
monosaccharides such as
glucose and
fructose from our diet. The intestinal absorption of
dietary carbohydrates such as
maltose and
sucrose is carried out by a group of α-
glucosidases. Inhibition of these
enzymes can significantly decrease the postprandial increase of
blood glucose level after a mixed
carbohydrate diet. Therefore, the inhibitory activity of Omija (Schizandra chinensis) extract against rat intestinal α-
glucosidase and porcine pancreatic α-
amylase were investigated in vitro and in vivo. The in vitro inhibitory activities of water extract of Omija pulp/skin (OPE) on α-
glucosidase and α-
amylase were potent when compared to Omija seeds extract (OSE). The postprandial
blood glucose lowering effect of Omija extracts 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
sucrose, OPE significantly reduced the
blood glucose increase after
sucrose loading. Furthermore, the
oxygen radical absorbance capacity (ORAC) of OSE and OPE was evaluated. OPE had higher
peroxyl radical absorbing activity than OSE. These results suggest that Omija, which has high ORAC value with α-
glucosidase inhibitory activity and
blood glucose lowering effect, could be physiologically useful for treatment of diabetes, although clinical trials are needed.