New Primula-type flavones from exudates of selected Dionysia spp. (Primulaceae)

Abstract

Hitherto unstudied Dionysia leucotricha and D. denticulata as well as new accessions of already studied species were analyzed for their exudate flavonoid profile. Results were compared with those of closely related species by HPLC-reinvestigation of existing exudate solutions. In addition to already known compounds typical of the Primula assemblage, three compounds were isolated from D. bryoides and identified as 2′-hydroxy-3′-methoxyflavone (1), 2′,3′- dimethoxyflavone (2) and 3′,5′-dimethoxyflavone (3), respectively, by HPLC and NMR. All compounds are new for the genus Dionysia, with compound 3 being novel and yet only described from synthesis. The occurrence of Primula-type flavones in Dionysia and the rare reports from genera outside Primulaceae are commented briefly.