INHIBITION OF POSTPRANDIAL HYPERGLYCEMIA BY OOLONG TEA EXTRACT (OTE)

Oolong tea extract (OTE) was found to inhibit sucrase from the small i ntestine and a-amylase. The IC50 values were 0.25mg/mL and 5.0mg/mL re spectively. The effect of OTE on postprandial hyperglycaemia was inves tigated in vivo in rats loaded with sucrose, maltose, soluble starch o r glucose. OTE suppressed the increase of blood glucose levels in sucr ose-, maltose- and glucose-loaded rats, but not in soluble starch-load ed rats. From these results it was assumed that orally administered OT E inhibits intestinal glycosidases, especially sucrase, thereby deterr ing the digestion of certain amounts of sucrose or maltose, and also i nhibits glucose absorption partially, leading eventually to a reductio n in blood glucose levels.