12-Nor-rotenoids and other cytotoxic constituents of Pachyrhizus erosus seeds

Five previously undescribed compounds, including three 12-nor-rotenoids, were isolated from Pachyrhizus erosus seeds. A brief survey on the dealkylation of selected rotenoids with BBr₃ was undertaken. Spectroscopic data of these previously undescribed compounds and reaction products are reported. The proposal of absolute configurations at stereocenters in the isolates and reaction products was based on NMR and ECD data. Most of the isolates and reaction products were evaluated for their growth inhibitory activities against four cancer cell lines and a Vero cell line. Many compounds exhibited strong to moderate activities with IC₅₀ values ranging from 0.06 to 20.9 μM, and their structure-activity relationships were evaluated.