Components of the essential oil from Petasites japonicus

The components of the essential oil from the leaves, roots and flower stems of Petasites japonicus were analysed by GC and GC–MS. As a result, 69 compounds, amounting to 84–91% of the total oil, were characterized. The major components of the leaf essential oil were β‐caryophyllene (22%) and valencene (15%). The root oil contained angelic acid (18%), eremophilene (10%) and α‐phellandrene (10%) as the major components. On the flower stem oil, valencene (12%), α‐phellandrene (11%) were the main components.