Synthesis of furofuran lignans as antidiabetic agents simultaneously achieved by inhibiting α-glucosidase and free radical.

Furofuran lignans such as sesamin have been recognized as promising antidiabetic agents as they possess curative as well as preventive effects toward diabetes complications. However, to date the structure-activity relationship has not been investigated due to the lack of a practical synthetic route capable of producing diverse furofuran lignans. Herein, we first introduced a single-step synthesis of these compounds starting from samin (4). Reaction of samin with a variety of electron-rich phenolics under acidic conditions afforded a total of 23 diverse furofuran lignans. On examination their inhibitions against α-glucosidase and free radicals, lignans having a free hydroxy group showed considerably enhanced inhibition, compared with their corresponding starter 4 and related lignans sesamin (1) and sesamolin (3). In addition, the mechanism underlying the α-glucosidase inhibition of a particular active lignan (epi -6) was verified to be mixed manner between competitive and noncompetitive inhibition.