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

•Synthesis of a new series of bis-indolone-N-oxides.•Their in vitro antiplasmodial, cytotoxic and antimicrobial activities were reported.•Compound 1a had the most potent antiplasmodial activity (IC50 = 0.763 μM).

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 (IC50 = 0.763 μmol L−1 on the FcB1 strain) with a selectivity index (CC50 MCF7/IC50 FcB1) of 35.6. No potency against the tested microbial strains was observed.

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