Antitumor activity of sesquiterpene lactones from Inula helenium and Inula japonica. Eight sesquiterpene lactones were isolated from the roots of Inula helenium and the flowers of I. japonica. The information contained herein is not intended to diagnose, treat, cure, alleviate, or prevent any disease or medical problem. It is recommended that you seek the advice of a qualified health care professional before beginning any natural, integrative, or traditional treatment. Over 500 pages of information on naturopathy and alternative therapies. This website is for informational purposes only. Otherwise, click here to become a member. Some features are currently available to members only. If you are already a member, please log in. japonica. Z Naturforsch C J Biosci.