Cyclopentabenzofuran lignan protein synthesis inhibitors from Aglaia odorata

In the course of screening for Ras function inhibitors, rocaglaol (1) and the related compounds, the known pyrimidinone (2) and the novel aglaiastatin (3), were isolated from a CHCl₃ extract of the leaves of Aglaia odorata. The structure of 3 was elucidated as a novel cyclopentabenzofuran on the basis of its NMR spectroscopic data and by X-ray crystallographic analysis. These compounds (1-3) were potent inhibitors of the growth of K-ras-NRK cells, with IC₅₀ values of 1-10 ng/mL, and induced normal morphology in K-ras-NRK cells at 10-30 ng/mL. They also specifically inhibited protein synthesis. Aglaiastatin (3) was slightly more potent than 1 and 2 in inhibiting cell growth. Aglaiastatin (3) reduced the amount of Ras, possibly by inhibiting its de novo synthesis.