“…Quercetin 3-O-glucuronic acid and kaempferol-3-O-glucoside were the dominant flavonoids, but quercetin 3-O-β-D-glucoside, patuletin 3-O-β-D-glucoside, kaempferol 3-O-β-D-glucuronide, 6-methoxykaempferol 3-O-β-D-glucoside, hispidulin, kaempferol, quercetin, apigenin, and rutine were also found. Protocatechuic and 3,5-dicaffeoylquinic acid were the major phenolic acids, but chlorogenic, caffeic, 1-methoxy-oxaloyl-3,5-dicaffeoylquinic acid, and 4,5-dicaffeoylquinic acid were also present [ 4 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. The acetone exudates of flower heads were richer in surface flavonoids than leaf extracts and presented high contents of the flavonoids 6-OH luteolin 6-methyl ether and kaempferol-6-methyl ether.…”