Five New Diterpenoids from the Seeds of Euphorbia lathyris

Abstract A new premyrsinane‐type diterpenoid, premylanin ( 1 ), and four new lathyrane‐type diterpenoids named Euphorbia Factors L 30 –L 33 ( 2 – 5 ) were isolated from the seeds of Euphorbia lathyris , together with thirteen known ones ( 6 – 18 ). Their structures were elucidated through spectroscopic analyses, including IR, UV, HR‐ESI‐MS, 1D‐ and 2D‐NMR. The cytotoxicities of compounds 1 – 4 and 6 – 18 against HCT116, MCF‐7, 786–0, HepG2 cell lines were evaluated, and compound 13 exhibited considerable cytotoxic activities with an IC 50 values of 6.44, 8.43, 15.3, 9.32 μ m , respectively.