The effect of novel [3-fluoro-(2-phosphonoethoxy)propyl]purines on the inhibition of Plasmodium falciparum, Plasmodium vivax and human hypoxanthine–guanine–(xanthine) phosphoribosyltransferases

Protozoan parasites from the Plasmodiidae family are the causative agents of malaria. Inhibition of hypoxanthine–guanine–(xanthine) phosphoribosyltransferase (HG(X)PRT) has been suggested as a target for development of new anti-malarial therapeutics. Acyclic nucleoside phosphonates (ANPs) are potent and selective inhibitors of plasmodial HG(X)PRTs. A new series of ANPs, based on the chemical structure and inhibitory activity of three ANPs, 2-(phosphonoethoxy)ethyl with either guanine or hypoxanthine as the base (PEEG and PEEHx) and 3-hydroxy-2-(phosphonomethoxy)propyl with guanine as the base (HPMPG), were prepared. These compounds are stereoisomers of 3-fluoro-(2-phosphonoethoxy)propyl (FPEPs) and 3-fluoro-(2-phosphonomethoxy)propyl (FPMPs) analogues. Both the (R)- and (S)-isomers of these fluorinated derivatives have higher Ki values (by 10- to 1000-fold) for human HGPRT and Plasmodium falciparum HGXPRT than the non-fluorinated ANPs. Possible explanations for these changes in affinity are proposed based on docking studies using the known crystal structures of human HGPRT in complex with PEEG. [Display omitted] •Novel FPEP acyclic nucleoside phosphonates.•Inhibitors of HG(X)PRT (Ki as low as 0.1 μM).•Proposed binding affinity of the inhibitors.