Antioxidation and α-glucosidase inhibitory activities of barley polysaccharides modified with sulfation

•New area of application needs to be explored for higher value added for barley.•This work might be the premier to modify barley polysaccharide with sulfation.•Sulfation raised the antioxidant activities of barley polysaccharide.•Derivatives showed mixed mechanism and kinetics against α-glucosidase.•Sulfated barley polysaccharide is potential in antiglycemia.

Barley is a cereal to seek for higher value added. Its β-glucan has been paid much attention as a soluble dietary fiber. Barley polysaccharide (BP) of a cultivar for brewing was extracted by ultrasonic assistance and derived by using a relatively lower toxic esterifying agent-sulfamic acid to obtain sulfated barley polysaccharides (SBPs) with various degrees of substitution (DS). Comparisons were made amongst SBPs and BP in antioxidant abilities in vitro with total reducing power, scavenging effect on DPPH, hydroxyl radicals, superoxide anion radicals and lipid antioxidation and inhibition against α-glucosidase. The results showed that antioxidant activity of BP was significantly enhanced by sulfation modification. The activities increased with the concentration and DS. Kinetic analyses revealed that the inhibitory effects of SBPs and BP on α-glucosidase were reversible and SBPs exhibited a mixed type of inhibition while BP was a noncompetitively inhibitory process. The present work reflected that BP could be a potential raw material for the development of antiglycemic pharmaceuticals.