Diospyros lotus L. fruit: A potential antidiabetic functional food targeting intestinal starch hydrolysis

Abstract

Post-meal hyperglycaemia is considered a prominent therapeutic target to attenuate the progression of diabetes and its associated complications. The present study identified fruit extract of Diospyros lotus Linnaeus, of the Ebenaceae family, as an inhibitor of starch digestion through the inhibition of both alpha amylase and alpha glucosidase. The extract inhibits porcine and human pancreatic amylase with IC50 values of 82.5±2.0 and 130.4±24 μg/ml respectively. The inhibition of intestinal sucrase and maltase activity was however considerably weaker. In vitro hydrolysis of solubilised potato starch into glucose yielded comparable inhibition kinetics for 100 μg/ml D. lotus L. extract and 3.5 μM acarbose. Screening the major phenolic constituents revealed that quercetin and myricetin were the strongest alpha amylase inhibitors. D. lotus L. extract showed strong antioxidant activity; however, this provided no meaningful protection against 2-deoxy-ribose induced oxidative stress in INS-1 cells. Taken together these findings identify D. lotus L. fruit as a multi-component functional food with potential to dampen the onset and development of diabetes through the inhibition of post meal hyperglycaemia.