Ferrocene–indole hybrids for cancer and malaria therapy

We report the synthesis, characterization, and cytotoxic and antimalarial activity of ferrocene–indole hybrids 8–14. The 2-phenylindole scaffold was chosen because of its potent antimitotic activity and ferrocene was chosen following the development of ferrocifens, ferrocene derivatives of tamoxifen, which are prototypes of a new family of organometallic anti-estrogens. Ferrocene–indole hybrids 8–14 and their corresponding organic analogues 1–7 showed only moderate antimalarial activities, while ferrocene–indole hybrids 11 and 12 showed excellent in vitro activities against the A549 human carcinoma cell line, with IC50 values of 5 and 7 μM respectively. These ferrocene–indole hybrids were up to 25-fold more potent as cytotoxic agents than their purely organic analogues.