Sesquiterpene lactones and their precursors as chemosystematic markers in the tribe Cichorieae of the Asteraceae revisited: An update (2008-2017)

Ten years after the first overview on sesquiterpene lactones in the Cichorieae tribe of the Asteraceae family, we present an update. This review summarizes all chemosystematically relevant reports on sesquiterpene lactones and their immediate precursors from the Cichorieae (syn.: Lactuceae) tribe of the Asteraceae published between 2008 and 2017 and also includes some corrections to the 2008 review. The number of sesquiterpene lactones and sesquiterpenic acids as immediate precursor of sesquiterpene lactones reported for the Cichorieae has increased from 360 to 475 (+ 32%) within one decade. The number of known source species increased from 139 to 157 (+ 13%) and the number of chemosystematic reports (reported compounds per taxon) increased from 838 to 1241 (+ 48%). Notwithstanding this high interest in sesquiterpene lactones of the Cichorieae, still only from 30 out of 94 currently accepted genera within the Cichorieae at least one sesquiterpene lactone has been reported so far.