Antimalarial properties of soy-bean fat emulsions

Intralipid^® and Ivelip^® are commercial preparations of soy-bean lipid extracts used for intravenous supplementation of lipids in various clinical conditions. They were found to inhibit the growth of Plasmodium falciparum in culture with an IC₅₀ of 8.07 ± 2.13 and 13.32 ± 2.05 mg.ml^-1, respectively. Intralipid^® rapidly and efficiently inhibited nucleic acid synthesis in cultured P. falciparum, exhibiting full inhibitory activity in less than 2 h. Ivelip^® injected intraperitoneally, was found by the 4-day suppressive test to be active in vivo against P. vinckei petteri within the normal recommended regimen for dietary lipid supply (0.5-4 g.kg^-1), but it was impossible to obtain a radical cure even with very high doses (6.4 g.kg^-1). Ivelip^® was less effective against P. berghei and P. yoelii nigeriensis. As Ivelip^® showed no interference with the antimalarial activity of chloroquine, it could be considered for use in the treatment of severe human malaria in association with 4-aminoquinolines to expedite the clearance of parasites.