α-Glucosidase inhibitors from the stems of Embelia ribes.

From the ethyl acetate extract of the stems of Embelia ribes (Myrsinaceae), a new alkenylresorcinol, embeliphenol A (1), together with 11 known compounds have been isolated. Their structures were elucidated on the basis of spectroscopic data. All compounds possessed significant α-glucosidase inhibitory activity in a concentration-dependent manner, except for 2 and 9. Compounds 1, 3-6, 8, and 12 showed more potent inhibitory activity, with IC50 values ranging from 10.4 to 116.7 μM, than that of a positive control acarbose (IC50 , 214.5 μM).