Flavonoids in frond exudates of Pityrogramma tartarea

Abstract From the frond exudate of Pityrogramma tartarea , a new dihydrochalcone, 2′,6′-dihydroxy-3,4,4′-trimethoxydihydrochalcone, and five complex flavonoids (D-1, D-2/a, calomelanols D, F and H) were isolated in addition to three known chalcones, three dihydrochalcones and three flavanones. Naturally occurring compounds which are assumed to be transformed from secondary metabolites in vitro by physical factors as found in exudates of species, such as Pityrogramma , Pentagramma , Primula etc., are defined as ‘tertiary metabolites’.