A Novel Pterocarpan Derivative From the Roots of Sophora flavescens

Flavescensin A (1), a novel rearrangement derivative of pterocarpan with an unusual spirotetrahydrofuran ring, along with 7 known pterocarpans were isolated from the roots of Sophora flavescens using several different chromatographic separations. The planar structure of 1 was elucidated by their nuclear magnetic resonance spectroscopic and high-resolution electrospray ionization mass spectrometry data, and the absolute configuration of 1 was determined on the basis of electronic circular dichroism data. Putative biosynthetic pathway toward 1 was proposed. In addition, all of the compounds were evaluated for their anti-influenza virus and anti-inflammatory activities.