α-Glucosidase inhibitors from the leaves of Embelia ribes

Abstract

A novel and rare 1,4-dehydrated ceramide, embelamide (1), and a new C-glycoalkaloid which is based on a β-carboline ring system, 1-(2′-deoxy-α-d-ribopyranosyl)-β-carboline (4), were isolated from the CHCl3 soluble fraction of the leaves of Embelia ribes (Myrsinaceae), together with thirteen known compounds (2–3, 5–15). Their structures were elucidated on the basis of spectroscopic data. Compounds 1, and 5–12 possessed significant α-glucosidase inhibitory activity in a concentration-dependent manner, and showed more potent inhibitory activity, with IC50 values ranging from 1.3 to 155.0μM, than that of a positive control acarbose (IC50, 214.5μM).