Leaf flavonoid diversity in the australian genus Patersonia

Abstract

In a leaf survey of 10 Patersonia species, six different flavonoid classes were detected: flavonol and flavone glycosides, 6-hydroxyflavonoids, flavone C-glycosides, biflavonoids and isoflavones. Twenty-nine flavonol glycosides, including seven with aliphatic acyl substitution, were found variously in these plants. Patersonia glabrata differed from the other nine taxa in producing amentoflavone and glycoflavones. Amentoflavone was found also in P. pygmaea but here and in the remaining species flavonol glycosides were the major constituents. However, all the taxa could be distinguished by their flavonoid profiles. For example, the unique presence of four unusual constituents scutellarein 7-methyl ether, quercetagetin 3,6,3′-trimethyl ether and the isoflavones tectorigenin and iristectorigenin A in the narrow-leaved P. occidentalis var. angustifolia clearly support its separation from the broad-leaved typical var. occidentalis as an independent species. Similarly, the seven differences in flavonoid pattern between P. sericea and P. longifolia support their recognition as separate species. The occurrence of biflavonoids in P. glabrata and P. pygmaea supports the placement of Patersonia in the Nivenioideae and the inclusion of Isophysis in the Iridaceae.