Oxytrodiflavanone A and Oxytrochalcoflavanones A,B: New Biflavonoids from Oxytropis chiliophylla.

Three previously undescribed biflavonoids, oxytrodiflavanone A (1), and oxytrochalcoflavanones A,B (2,3), were isolated from the aerial part of Oxytropis chiliophylla, together with their putative biosynthetic monomers, i.e., (2S)-5,7-dihydroxyflavanone (4), (2S)-7-hydroxyflavanone (5), and 2',4'-dihydroxychalcone (6). The structures of these compounds were elucidated by a combination analysis of spectroscopic data. The cytotoxic activities of all the isolated compounds against PC-3 human prostate cancer cell line are also presented.