Aim: To study the antimalarial effect of agmatine (Agm) on chloroquine-susceptible Plasmodium berghei K173 strain (S strain) and the P berghei K173 resistant strain (R strain).
Methods: The antimalarial effects of Agm on P berghei K173 S strain and R strain were evaluated by Peters 4-d suppression test in mice.
Results: Agm (12.5-200 mg/kg, ig, daily) decreased the parasitemia for both P berghei K173 S strain (IC(50)=139 mg/kg) and R strain (IC(50)=126 mg/kg) in mice. Subcutaneous injection (sc) of Agm (5-40 mg/kg, tid) showed relatively stronger antimalarial effect than intragastric gavage (IC(50)=30 mg/kg ) in P berghei K173 S strain. Spermidine antagonized the antimalarial effect of Agm for P berghei K173 S strain and R strain. Agm did not reverse the chloroquine resistance of P berghei K173 S strain. dl-alpha-Difluoromethylornithine (DFMO, sc) decreased the parasitemia of P Berghei K173 S strain and this effect was antagonized by spermidine.
Conclusion: Agm has an antimalarial effect and the mechanism is related to its inhibition of polyamine synthesis.