Synthesis and evaluation of benzophenone O-glycosides as α-glucosidase inhibitors.

The first total synthesis of benzophenone O-glycosides (iriflophenone 2-O-α-L-rhamnopyranoside: 1 and aquilarisinin: 2) isolated from the leaves of Aquilaria sinensis and related new derivatives (3-12) was accomplished through suitable protecting group manipulations and glycosylation starting from commercially available L-rhamnose, D-glucose, D-galactose, D-mannose, D-xylose, and 1,3,5-trihydroxybenzene. All synthesized benzophenone O-glycosides were evaluated for their inhibitory activities against α-glucosidase. Of these, benzophenone O-glycosides 4 and 10 exhibited the most potent inhibitory activity in vitro against α-glucosidase with IC(50) values of 168.7 ± 13.9 and 210.1 ± 23.9 µM, respectively, when compared with that of the positive control acarbose with an IC(50) value of 569.3 ± 49.7 µM.