On the mechanism of the antitumor activity of ferrocenium derivatives

Contradictory results exist in the literature about the antineoplastic acti vity of ferrocenes and their ferrocenium salts; additionally, little is kno wn about the mechanism by which such drugs become active towards cancer cel ls. In the present paper we show that only ferrocenium species are able to inhibit the growth of Ehrlich ascites tumor cells in vivo and we propose th at the cytotoxic activity of ferrocenium salts is not based on their direct linking to DNA, but on their ability to generate oxygen active species whi ch induce oxidative DNA damage. (C) 2000 Elsevier Science S.A. All rights r eserved.