Flavonoid chemistry of Blennospermatinae, a trans-Pacific disjunct subtribe of Senecioneae ( Asteraceae).

The flavonoid profiles of seven species of Abrotanella and one species of Ischnea have been shown to be based upon kaempferol 3- and quercetin 3- O-glycosides and a delphinidin glycoside. Glucosides, glucuronides, arabinosides, diglucosides, and rutinosides of the flavonols were identified. The profile of Ischnea consisted solely of quercetin 3- O-glucoside and 3- O-arabinoside whereas the profiles of the Abrotanella species were more varied. Although infraspecific variation was not investigated in this study, the flavonoid chemistry of the two genera is in accordance with the flavonoid variation described for other members of Senecioneae which are primarily flavonol producers. Based on the known phylogeny and biogeography, the flavonoid distribution from the perspective of long-distance dispersals across the Pacific is discussed. Such events should lead to genetic bottle-neck situations and depauperate flavonoid profiles. A summary of current flavonoid knowledge in the Senecioneae is supplied. [ABSTRACT FROM AUTHOR]