Steam distillation of the roots and rhizomes of Elecampane produces an essential oil that consists primarily of sesquiterpene lactones, such as Alantolactone (aka Helenin, and also previously described as being 'Alantic Acid' until its lactone characteristic was determined), Isoalantolactone (a double-bond isomer of Alantolactone), Isocostunolide and Helenalin (not to be confused with Helenin, mentioned just before), which can cause a contact allergenic response in some people; therefore the oil is not suitable for aromatherapy.
Alantolactone seems to stimulate blood circulation in smaller areas of the body. Isocostunolide induces mitochondrial membrane depolarization and caspase-dependent apoptosis in human melanoma cells.
Helenalin is highly toxic with potent anti-involuntary and anti-tumour properties and may be effective as a treatment for MRSA. Sesquiterpenes are reactive molecules; helenanin can form covalent bonds with proteins containing free SH groups, to the detriment of the organism. When sesquiterpene lactones bind to proteins, they can become antigens, activating antibodies, which go on to cause allergic reactions with further exposure to sesquiterpenes.
The essential oil has been used to flavour bitter alcoholic drinks, such as Vermouths, as well as non-alcoholic drinks, confectionary, baked goods, gelatins and puddings.
Not one of these has approval as a pharmaceutical. Over a 1000 different lactones have been identified in plants of the Daisy family of which Elecampane is a member.