A Novel Class of Complex Flavonoids from the Frond Exudate of Pityrogramma trifoliata

Abstract

Fronds of the neotropical fern Pityrogram m a trifoliata produce a farinose exudate which consists mainly of a dihydrochalcone. The structure of som e minor constituents has been elucidated by spectroscopic m ethods. They are shown to be representatives of a novel class of complex flavonoids, com posed of a flavonoid and a neoflavonoid moiety. In other terms, they are 5,7-di-hydroxy-8-cinnamoyl-4-phenyl-dihydrocoumarins. The occurence of these and closely related compounds in this fern’s exudate supports its inclusion in the genus Pityrogramma.