Stachyodin A, a pterocarpan derivative with unusual spirotetrahydrofuran ring from the roots of Indigofera stachyodes

Abstract Stachyodin A ( 1 ), a rearrangement product of pterocarpan featuring a 6/5/5/6 tetracyclic ring system with an unusual spirotetrahydrofuran ring, and stachyodin B ( 2 ), a new dihydrochalcone, along with five known analogues ( 3 – 7 ) were isolated from the roots of Indigofera stachyodes . The structures of 1 and 2 were elucidated on the basis of their HRESIMS and NMR spectroscopic data, and their absolute configurations were determined by X-ray crystallographic analysis and electronic circular dichroism (ECD) data, respectively. Compounds 2 – 4 showed inhibition of nitric oxide production in lipopolysaccharide-activated BV-2 microglial cells.