Antitumor activity of some natural flavonoids and synthetic derivatives on various human and murine cancer cell lines

The effect of various natural flavonoids, cinnamic acid derivatives, and a series of synthetic flavones on cell proliferation was evaluated in vitro in a panel of established human and murine tumor cell lines. The most potent antiproliferative agents were caffeic acid n-butyl ester (12) > 2'-nitroflavone (26) > caffeic acid ethyl ester (11) similar to 2',6-dinitroflavone (27) > apigenin (3) > 3'-bromoflavone (20) similar to 2'-fluoro-6-bromoflavone (31). Some compounds showed a moderate effect, the order of cytotoxic activities being chrysin (2) > 2'-fluoro-6-chloroflavone (30) similar to 2'-chloroclirysin (32) > alpha-naphthoflavone (7) > beta-naphthoflavone (8) similar to 6-chloroflavone (14) similar to 6-bromoflavone (15) similar to 4'-nitroflavone (23). A structure-activity relationship analysis of each group of compounds was performed. None of the natural or synthetic compounds tested affected the proliferation of epithelial cells derived from normal mammary gland of mice or fibroblastic cells from mouse embryo, suggesting a selective action against tumor cells. (c) 2005 Elsevier Ltd. All rights reserved.