Synthesis and biological evaluation of new bis-indolinone derivatives endowed with cytotoxic activity

A series of new Knoevenagel adducts, bearing two indolinone systems, has been synthe-sized and evaluated on 60 human cancer cell lines according to protocols available at the National Cancer Institute (Bethesda, MD, USA). Some derivatives proved to be potent antiproliferative agents, showing GI50 values in the submicromolar range. Compound 5b emerged as the most active and was further studied in Jurkat cells in order to determine the effects on cell-cycle phases and the kind of cell death induced. Finally, oxidative stress and DNA damage induced by compound 5b were also analyzed.