Flavonoids and other phenolics of Cichorium and related members of the Lactuceae (Compositae)

Extraction of the leaves of chicory, Cichoriumintybus, revealed the presence for the first time of the 3-glucuronides of kaempferol, quercetin and isorhamnetin, the 3-glucoside of kaempferol and the 7-glucuronide of luteolin. The same compounds appear to occur throughout the genus. An aglycone survey of the leaves of 240 other members of the Lactuceae failed to reveal any other source of isorhamnetin, although quercetin and kaempferol were found as occasional constituents in 12 other genera. In Lactuca, a survey of 12 species showed eight with quercetin present. In general, though, flavonols are more uncommon than flavones and thus have more potential as taxonomic markers within the tribe. The coumarins cichoriin and aesculin and the caffeoyl-tartaric acid ester, chicoric acid, were also found to be present widely in the tribe.