Abiesatrines A-J: anti-inflammatory and antitumor triterpenoids from Abies georgei Orr.

A novel spiro-lanostane (abiesatrine A, 1) was isolated from the aerial parts of Abies georgei together with 9 new (abiesatrines B-J, 2-10) and 10 known triterpenes (11-20). The new structures were established by the extensive analysis of their spectroscopic data. The configuration of 1, featuring a unique spirolactone formed by C-13 and C-23 via oxygen-bridge, was confirmed by X-ray crystallography, and its biopathway was tentatively proposed. Among these isolates, compound 16 showed the strongest inhibitory activity against LPS-induced NO production in RAW264.7 macrophages (IC(50) = 8.9 microg mL(-1)). While compounds 1 and 20 exhibited potent anti-proliferative effects on QGY-7703 cells with IC(50) values of 9.3 and 7.6 microg mL(-1), respectively. Preliminary structure-activity relationship (SAR) investigations defined structural feature of the 24Z-olefinic bond key to the lanostane and cycloartane pharmacophore.