Four New Diterpenoids from the Roots of Euphorbia pekinensis.

Three new isopimarane diterpenoids (1 - 3) and one new abietane diterpenoid (4) were isolated and identified from the roots of Euphorbia pekinensis, together with four known diterpenoids. Their structures were elucidated on the basis of extensive spectroscopic methods (IR, MS, NMR, and CD), and their cytotoxicities and anticomplement activities were evaluated.