Cytotoxicity of flavonoids and sesquiterpene lactones from Arnica species against the GLC4 and the COLO 320 cell lines. - Woerdenbag ,H.J,.; Merfort ,I,.; Pabreiter ,C.M,.; Schmidt ,T.J,.; Willuhn ,G,.; Van Uden ,W,.; Pras ,N,.; Kampgina ,H.H,.; Konings ,A.W.. (Planta Med., 1994)