Using HPLC-MSn, 33 chlorogenic acids were identified in an aqueous-alcoholic extract of Aster ageratoides Turcz. flower buds. These were three isomers each of p-coumaroylquinic acid, caffeoylquinic acid, feruloylquinic acid, dicaffeoylquinic acid and diferuloylquinic acid, and six isomers each of p-coumaroyl-caffeoylquinic acid, p-coumaroyl-feruloylquinic acid and caffeoyl-feruloylquinic acid. Only the caffeoylquinic acids and dicaffeoylquinic acids have been reported previously in Asteraceae. Three of the six p-coumaroyl-feruloylquinic acids (...