New ingol diterpenoids from the aerial parts of Euphorbia royleana Boiss

Three new ingol diterpenoids, 8,12-O-diacetylingol-7-benzoyl-3-tiglate (1), 12-O-acetylingol-3,7-dibenzoyl-8-tiglate (2) and 3,12-O-diacetyl-7-O-benzoylingol-8-tiglate (3), were isolated from the aerial parts of Euphorbia royleana, together with three known ingol derivatives (4-6). Their structures were elucidated by the extensive HR-MS, 1H NMR, 13C NMR, HSQC, HMBC, 1H-1H COSY, ROESY and CD analyses. The cytotoxic activities of 1-3 were evaluated by MTT methods.