New abietane and tigliane diterpenoids from the roots of Euphorbia fischeriana and their cytotoxic activities.

Three new abietane and two new tigliane diterpenoids were isolated from the roots Euphorbia fischeriana. Their structures were elucidated by spectroscopic methods and quantum chemical calculation. Compounds 4 and 5 exhibited the inhibitory activities against human cancer cells HeLa and HepG2, with IC50 ranging from 3.54 to 11.45 µM.