Phenylethyl cinnamides: A new series of α-glucosidase inhibitors from the leaves of Aegle marmelos

A series of phenylethyl cinnamides, which included new compounds named anhydromarmeline (1), aegelinosides A (7) and B (8), were isolated from Aegle marmelos leaves as α-glucosidase inhibitors. The structures of new compounds were characterized by spectroscopic data and chemical degradation. Of compounds isolated, anhydroaegeline (2) revealed the most potent inhibitory effect against α-glucosidase with IC50 value of 35.8 μM. The present result also supports ethnopharmacological use of A. marmelos as a remedy for diabetes mellitus.