Four isoflavanones from roots of Sophora tetraptera

Four new isoflavanones, tetrapterols F–I, were isolated from roots of Sophora tetraptera in addition to seven known flavonoids, lupinifolin, 8- O-methylretusin, 5,7,4′-trihydroxy-6,3′-di( γ, γ-dimethylallyl)isoflavone, (−)-maackiain, sophoracarpan A, medicagol and 2-(2,4-dihydroxyphenyl)-5,6-methylenedioxybenzofuran. The structure of the new isoflavanones was determined to be 3,5,7–trihydroxy-2′-methoxy-8- γ, γ-dimethylallyl-6‴,6‴-dimethylpyrano[2‴,3‴:4′,3′]isoflavanone(tetrapterol F), 5,7,2′,4′-tetrahydroxy-6,5′-di( γ, γ-dimethylallyl)isoflavanone(tetrapterol G), 5,7,2′–trihydroxy–4′–methoxy-8,5′-di( γ, γ-dimethylallyl) isoflavanone(tetrapterol H) and 7,4′-dihydroxy-6,3′-di( γ, γ-dimethylallyl)isoflavanone (tetrapterol I) by means of spectroscopic analysis.