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 13 g and 14 g 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 13 g and 14 g were also evaluated against chloroquine-resistant PfDd2 and displayed IC₅₀ values of 0.11 and 0.10 μM, respectively. Next, 13 g and 14 g were administered to the Plasmodium berghei mice model at 30 mg/kg intraperitoneally for four consecutive doses, which showed 25 % and 50 % reduction in the parasitemia load, respectively. The efficacy of hits 13 g and 14 g was improved along with mean survival time when administered in combination with artesunate. On liver-stage parasites, compounds 13 g and 14 g showed >80 % inhibition at 1 μM. Compound 14 g was also tested for toxicity in mice at 100 mg/kg dose, which revealed no abnormality in mice organs. Preliminary pharmacokinetic studies of compound 14 g exhibited absorption and maintained a presence in the body for more than six hours.