Ingol and ingenol diterpenes from the aerial parts of Euphorbia royleana and their antiangiogenic activities.

Ten new ingol lathyrane-type diterpenes (1-10) and two known ingenol derivatives (11 and 12) were isolated from the aerial parts of Euphorbia royleana. The structures of 1-10 were elucidated on the basis of spectroscopic methods including 2D NMR analysis, and the structure of compound 1 was confirmed by single-crystal X-ray crystallography. Antiangiogenic effects of all compounds except for 5 were tested using a zebrafish model, with compounds 11 and 12 being active in this bioassay.