RESUMEN
Aim To detect the antitumor activities of five sesquiterpene lactones from the roots of Inula helenium.Method Using MTT assay to evaluate the antitumor activities of five sesquiterpene lactones to the cell lines of U251SP,T-98,HLE,MM1-CB,HMV-1 and KT,and to explore the relationship between structure and activities.Results Isoalantolactone exhibited significant anti-growth activities to U251SP,HLE and MM1-CB,while other compounds demonstrated weak or moderate anti-growth activities to cell lines even in the 50% inhibition concentration≤100 μmol·L~(-1).Conclusion Isoalantolactone exhibits significant anti-growth activities to three cell lines and its anti-tumor activitiesve close relationship with the structures,α,β-unsaturated five-membered lactone ring is necessary for the activities,and saturated lactone or 5,10-seco and A,B-ring become a ten-membered macro-ring leading to the loss or decrease of anti-growth activity.