Total Synthesis and Anti-Inflammatory Activity of Tectoridin and Related Isoflavone Glucosides

The first total syntheses of four isoflavone glucosides, tectoridin ( 1 ), tectoridin A ( 2 ), tectorigenin 7- O -β- d -glucopyranosyl-12- O -β- d -glucopyranoside ( 3 ), and isotectroigenin 7- O -β- d -glucopyranoside ( 4 ), have been accomplished. Key steps in our synthetic approach include a regioselective halogenation reaction, followed by methanolysis to introduce the −OCH 3 group into isoflavone frameworks and a PTC-promoted stereoselective glycosidation to establish glycosidic bonds. The synthesized isoflavone glucosides ( 1 – 4 ) and their corresponding aglycones ( 32 and 34 ) were evaluated for anti-inflammatory activity against nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1 β (IL-1β) in lipopolysaccharide (LPS)-induced RAW264.7 cells. Aglycones 32 and 34 exhibited stronger anti-inflammatory activity in vitro compared to isoflavone glucosides 1 – 4 .