Isoflavones and xanthones from Polygala virgata

Three isoflavones and two xanthones have been isolated from the roots of Polygala virgata. The structures were established on the basis of spectral data of the isolates and of some derivatives. 5,7,4′-Trihydroxy-6,8-dimethoxyisoflavone and 5,7-dihydroxy-6,8,4'-trimethoxyisoflavone are new natural products, whereas 5,7-dihydroxy-8,4′-dimethoxyisoflavone, although known synthetically, is reported here for the first time as a naturally occurring compound. The isolated xanthones (1,7-dihydroxy-2,3,4-trimethoxyxanthone and 1,7-dihydroxy-3,4-dimethoxyxanthone) have been described previously in other species.