Tetraoxygenated Xanthones from Centaurium erythraea

Abstract
Three tetraoxygenated xanthones, 1,6-dihydroxy-3,5-dimethoxyxanthone, 3-hydroxy-1,5,6-trimethoxyxanthone and 1,3,5-trihydroxy-2-methoxyxanthone, were isolated for the first time from the aerial parts of C. erythraea. Their structures were established by spectroscopic means and by comparison with literature references.