Screening of Jordanian Flora for alpha-Amylase Inhibitory Activity

Thirty-five plant species that belong to different families were tested for alpha-amylase inhibitory activity. Four of the screened plants exhibited significant (more than 80%) alpha-amylase inhibitory activity. IC50 values for these plants were estimated based on the dried crude extract and found to be 0.08, 0.13, 0.32, and 0.47 mg/ml, for Osyris alba L. (Santalaceae), Sarcopotarium spinosum L. (Rosaceae), Hypericum triquetrifolium Turra (Hypericaceae) and Arbutus andrachne L. (Ericaceae), respectively. Amylase inhibitory activity was also evaluated in vivo using female rats. Results showed that the tested extracts had a favorable effect on blood glucose level after ingestion of a high dose of sucrose. The most potent extract in controlling the surge of glucose after sucrose ingestion appeared to be O. alba which also exhibited the highest alpha-amylase inhibitory activity in vitro.