Cytotoxic activity and effect on nitric oxide production of tirucallane-type triterpenes

Hexane extract from the bark of Amphipterygium adstringens, as well as its principal constituents, masticadienonic acid (1) and 3α‐hydroxymasticadienolic acid (2), inhibited the growth of five human cancer cell lines. Derivatives of 1, namely 24,25S‐dihydromasticadienonic acid (3) and masticadienolic acid (4), were also evaluated. The results showed that both 3 and 4 had greater activity than 1 on colon cancer cell lines. The effects of 1–4 on the production of nitric oxide (NO) from both resting and lipopolysaccharide‐activated macrophages were determined. It was found that 1, 2 and 4 caused an increase in NO release from resting macrophages; in lipopolysaccharide‐activated macrophages, only 2 and 4 caused an increase in NO production.