Synthesis of New α-Glucosidase Inhibitors Based on Oleanolic Acid Incorporating Cinnamic Amides

A series of a-glucosidase inhibitors with the oleanolic acid core and different cinnamic amide ligands were designed and synthesized. Their preliminary structure activity relationships were analyzed. In general, the compounds with 3,28-disubstituted oleanolic acid exhibited stronger activity than those 28-monosubstituted analogues, and variation of cinnamic amide substitution significantly affected alpha-glucosidase inhibition activities. Most of the compounds showed potent inhibitory activity against alpha-glucosidase with much greater efficacy than a typical alpha-glucosidase inhibitor, acarbose.