linoleic-acid and Parasitemia

Vegetable oils are frequently used as solvents for lipophilic materials; accordingly, the effects of their components should be considered in animal experiments. In this study, the effects of various vegetable oils on the course of Trypanosoma congolense infection were examined in mice. C57BL/6J mice were orally administered four kinds of oils (i.e., coconut oil, olive oil, high oleic safflower oil, and high linoleic safflower oil) with different fatty acid compositions and infected with T. congolense IL-3000. Oil-treated mice infected with T. congolense showed significantly higher survival rates and lower parasitemia than those of control mice. Notably, coconut oil, which mainly consists of saturated fatty acids, delayed the development of parasitemia at the early stage of infection. These results indicated that vegetable oil intake could affect T. congolense infection in mice. These findings have important practical implications; for example, they suggest the potential effectiveness of vegetable oils as a part of the regular animal diet for controlling tropical diseases and indicate that vegetable oils are not suitable solvents for studies of the efficacy of lipophilic agents against T. congolense.

Topics: Animals; Body Weight; Coconut Oil; Energy Intake; Linoleic Acid; Male; Mice; Mice, Inbred C57BL; Oleic Acid; Olive Oil; Parasitemia; Plant Oils; Safflower Oil; Trypanosoma congolense; Trypanosomiasis, African

Following the demonstration of the antimalarial effect of the long chain saturated alcohol n-hentriacontanol ((CH2)29CH2OH), isolated from the Bolivian endemic solanaceous plant Cuatresia sp., we have tested the effect of the C18 fatty acids oleic, elaidic, linoleic, and linoleic on malaria parasites. These fatty acids inhibited the parasitemic development in mice infected with Plasmodium vinckei petteri or with Plasmodium yoelii nigeriensis in a 4-day suppressive test. To gain a deeper discernment of the antimalarial mode of action, the effects of these compounds were evaluated on Plasmodium falciparum growth in culture. Whereas n-hentriacontanol did not show any inhibition of this parasite, on the contrary, the C18 acids displayed a considerably inhibitory activity at < or = 200 micrograms/ml both in intact infected cells and in free parasites. In order to understand the mechanism of their antimalarial action, several tests were performed. No hemolysis of infected cells could be observed up to 500 microgram/ml. No effect on the lipid peroxidation, ATP levels, transport through the parasite-induced permeability pathways, or on the phagocytosis of the infected cells could be observed. The cytotoxic effect of the fatty acids was very rapid: full inhibition of nucleic acids and protein syntheses was observed in less than 30 min. This inhibition was not relieved by the addition of deferrioxamine or FeCl3, indicating that fatty acids (FA) do not act by facilitating the transport of iron. Inhibition was relieved in neither the presence of orotic acid or its methyl ester, indicating that FA do not act at the mitochondrial level of pyrimidine synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: alpha-Linolenic Acid; Animals; Antimalarials; Fatty Acids, Nonesterified; Linoleic Acid; Linoleic Acids; Malaria; Male; Mice; Oleic Acid; Oleic Acids; Parasitemia; Plasmodium; Plasmodium falciparum; Plasmodium yoelii; Structure-Activity Relationship