Phaseollin A, a novel pterocarpan with a unique 6/7/5/6/6 skeleton from Phaseolus lunatus L.

A novel pterocarpan, named phaseollin A (1) was isolated from Lima bean (the seeds of Phaseolus lunatus L.). The structure of 1 was elucidated by the extensive spectroscopic analysis (1D and 2D NMR, HR-ESI-MS) as well as the experimental and calculated ECD data analysis. Compound 1 showed moderate activity of inhibiting NO production on lipopolysaccharide (LPS)-induced RAW264.7 cells with IC50 value of 37.13 ± 2.58 μM.