Cytotoxic triterpenoids from Abies recurvata

Nine triterpenoids (neoabiestrines A–I, 1–9) including six rearranged lanostanes (1–6) and a rare cycloart-7-ene (7) were isolated from Abies recurvata together with ten known compounds. Their structures were determined by detailed analysis of NMR and MS spectroscopic data. The absolute configurations of 1 and 8 were determined by Cu-Ka X-ray crystallography. Compound 6 showed potent anti-proliferative effect against THP-1 tumor cells with an IC50 value of 17.8μg/mL.