An unusual homoisoflavanone and a structurally-related dihydrochalcone from Polygonum ferrugineum (Polygonaceae)

A homoisoflavanone (1) and a dihydrochalcone (2) were isolated from dry leaves of Polygonum ferrugineum (Polygonaceae), along with five known chalcones and flavanones. Structures were assigned on the basis of 1 and 2D NMR spectral studies. This is the first report on the occurrence of an homoisoflavanone in Polygonum genus. In addition, it possess distinctive features respective to other homoisoflavanones previously isolated from natural sources and could be an important finding from the point of view of chemosystematic of the genus.