Synthesis and evaluation of fluorinated piperazine-hydroxyethylamine analogues as potential antiplasmodial candidates.

In this manuscript, twenty-one novel fluorinated piperazine-hydroxyethylamine analogues were synthesized and tested against Plasmodium falciparum (Pf). Among tested compounds, two 13g and 14g exhibited promising inhibitory activity on Pf3D7 with IC50 values of 0.28 and 0.09 µM, respectively. Neither of the hits exhibited cytotoxicity on HepG2 cells up to 150 µM and Vero cells up to 20 µM. Compounds 13g and 14g were also evaluated against chloroquine-resistant PfDd2 and displayed IC50 values of 0.11 and 0.10 µM, respectively. Next, 13g and 14g were administered to the Plasmodium berghei mice model at 30mg/kg intraperitoneally for four consecutive doses, which showed 25% and 50% reduction in the parasitemia load, respectively. The efficacy of hits 13g and 14g was improved along with mean survival time when administered in combination with artesunate. On liver-stage parasites, compounds 13g and 14g showed >90% inhibition at 1µM. Compound 14g was also tested for toxicity in mice at 100 mg/kg dose, which revealed no abnormality in mice organs. Preliminary pharmacokinetic studies of compound 14g exhibited absorption and maintained a presence in the body for more than six hours.