Antitumor activity of flavones isolated from Artemisia argyi

The flavones 5,6-dihydroxy-7,3',4'-trimethoxyflavone ( 1), 5,6,4'-trihydroxy-7,3'-dimethoxyflavone ( 2), 5-hydroxy-3',4',6,7-tetramethoxyflavone, 5,7,3'-trihydroxy-6,4',5'-trimethoxyflavone, ladanein, and hispidulin were isolated from the methanolic extracts of the aerial parts of Artemisia argyi and structures of the compounds were elucidated on the basis of their spectral data. These flavones inhibited farnesyl protein transferase with IC 50 values of 25 - 200 microg/mL. Compound 2 inhibited proliferation of a couple of tumor cell lines and also inhibited neovascularization in a chick chorioallantoic membrane assay. Without loss of body weight of nude mice, compounds 1 and 2 inhibited growth of a colon tumor (SW620) by 44.6 % and 14.6 %, respectively.