Flavonoid chemistry of Calyceraceae

Flavonoid profiles were determined for 11 species representing five genera of Calyceraceae: Acicarpha, Boöpis, Calycera, Gamocarpha, and Nastanthus. Kaempferol, quercetin, 6-methoxykaempferol, and 6-methoxyquercetin (patuletin) were unequivocally identified. Kaempferol and quercetin occurred as 3-O-mono- and 3-O-diglycosides, whereas the latter two flavonols were observed only as aglycones. Several unidentified phenolic compounds were also noted. The simplest profile in the family consisted solely of the kaempferol and quercetin glycosides in Acicarpha, Gamocarpha, and one specimen of Calycera leucanthema. Morphological evidence suggests that Acicarpha represents prototypical Calyceraceae and that a close relationship exists between primitive Calyceraceae and some basal members of Asteraceae (subfamily Barnadesioideae). This last possibility is reinforced by the similarity of flavonoid profiles of Acicarpha and members of Barnadesioideae.