Anti-malarial effect of gum arabic

Background: Gum Arabic (GA), a nonabsorbable nutrient from the exudate of Acacia senegal, exerts a powerful immunomodulatory effect on dendritic cells, antigen-presenting cells involved in the initiation of both innate and adaptive immunity. On the other hand GA degradation delivers short chain fatty acids, which in turn have been shown to foster the expression of foetal haemoglobin in erythrocytes. Increased levels of erythrocyte foetal haemoglobin are known to impede the intraerythrocytic growth of Plasmodium and thus confer some protection against malaria. The present study tested whether gum arabic may influence the clinical course of malaria. Methods: Human erythrocytes were in vitro infected with Plasmodium falciparum in the absence and presence of butyrate and mice were in vivo infected with Plasmodium berghei ANKA by injecting parasitized murine erythrocytes (1 x 10(6)) intraperitoneally. Half of the mice received gum arabic (10% in drinking water starting 10 days before the day of infection). Results: According to the in vitro experiments butyrate significantly blunted parasitaemia only at concentrations much higher (3 mM) than those encountered in vivo following GA ingestion (<1 mu M). According to the in vivo experiments the administration of gum arabic slightly but significantly decreased the parasitaemia and significantly extended the life span of infected mice. Discussion: GA moderately influences the parasitaemia and survival of Plasmodium-infected mice. The underlying mechanism remained, however, elusive. Conclusions: Gum arabic favourably influences the course of murine malaria.