Eurifoloids A-R, structurally diverse diterpenoids from Euphorbia neriifolia.

Eighteen new diterpenoids, named eurifoloids A–R (1–18), including ingenane (1 and 2), abietane (3–7), isopimarane (8–12), and ent-atisane (13–18) types, along with four known analogues were isolated from Euphorbia neriifolia. Eurifoloid M (13) represents a rare class of ent-atisane-type norditerpenoid. Eurifoloids E (5) and F (6) exhibited significant anti-HIV activities, with EC50 values of 3.58 ± 0.31 (SI = 8.6) and 7.40 ± 0.94 μM (SI = 10.3), respectively.