Synthesis and biological evaluation of new bis-indolone-N-oxides

Abstract A series of bis -indolone- N -oxides, 1a–f , was prepared from bis (ethynyl)benzenes and o -halonitroaryls and studied for their in vitro antiplasmodial activities against Plasmodium falciparum and representative strains of bacteria and candida as well as for their cytotoxicity against a human tumor cell line (MCF7). They did not cause any haemolysis (300 μg mL −1 ). Of the synthesized bis -indolones, compound 1a had the most potent antiplasmodial activity (IC 50  = 0.763 μmol L −1 on the FcB1 strain) with a selectivity index (CC 50 MCF7/IC 50 FcB1) of 35.6. No potency against the tested microbial strains was observed.