OBJECTIVETo investigate the effects of Xanthium sibiricum Patrin ex Widder water extracts (CEW) on α-glucosidase activity (AG) and blood sugar in mice.

METHODSThe inhibition of AG by CEW was studied with enzyme-inhibitor screening external model with acarbose as control drug. The normal mice were administrated by gavage with 40.0g*kg(-1), or 10.0 g*kg(-1) of CEW, 0.375 g*kg(-1) of acarbose, and 0.3ml of normal saline, respectively in successive 5 days; then the animals were loaded with 2.0 g*kg(-1) of glucose, 4.0 g*kg(-1) of sucrose, and 2.0 g*kg(-1) of starch and blood sugar levels were measured within 15, 30, 60, and 120min. Diabetes was induced by injection of streptozotocin (STZ) in mice, then 40.0 g*kg(-1), or 10.0 g*kg(-1) of CEW was given to diabetic mice in successive 2 weeks and 4 weeks, then the blood sugar levels were measured.

RESULTSIn the enzyme inhibition test, when the concentration of CEW was between 0.3125 g*L(-1)-10.00 g*L(-1), the inhibition rate was 55.42%-92.73% when the concentration of acarbose was 1.5625 g*L(-1)-25.00 g*L(-1), the inhibition rate was 9.28%-64.87%. In the sugar tolerance test, the blood sugar value in starch-loaded mice decreased sharply (P<0.01), followed by sucrose-loaded group (P<0.05), and there was no change in glucose-loaded group (P>0.05). In diabetic mice CEW-40 and CEW-10 groups showed significant blood sugar lowering effect (P<0.01 or P<0.05).

CONCLUSIONCEW has stronger effect in inhibition of AG activity than acarbose. CEW can increase the sugar tolerance in normal mice and decrease the blood sugar level in diabetic mice..