Synthesis, selective cytotoxicities and probable mechanism of action of 7-methoxy-3-arylflavone-8-acetic acids

Thirteen new analogues of flavone-8-acetic acid, that is, compounds 10a-m bearing a methoxy group at the 7-position and diverse subsitiuents on the benzene ring at the 2- and 3-positions of flavone nucleus, were synthesized and evaluated for their direct antiproliferative effects on two human tumor cell lines and for their indirect antiproliferative activities in the transwell co-culture system. The results indicated that most of compounds 10a-m showed moderate direct cytotoxicities. Among them, compound 10i exhibited higher direct cytotoxicity and selectivity for both cell lines over BJ human foreskin fibroblast cells than 5,6-dimethylxanthenone-4-acetic acid (DMXAA). Interestingly, compared with DMXAA, compound 10e showed comparable indirect cytotoxicity and higher selectivity. In addition, compound 10e was found to be able to induce tumor necrosis factor α (TNF-α) production in human peripheral blood mononuclear cells.