BACKGROUND: Reports on the antischistosomal effect of several antimalarial drugs 
such as artesunate, mefloquine, and amodiaquine suggest that febrifugine, which 
exerts an antimalarial effect, can also be expected to possess antischistosomal 
potential. The present study investigates the antischistosomal effects of 
febrifugine.
METHODS: In experiment 1, Schistosoma mansoni adult worm pairs were incubated in 
a medium alone as a control or supplemented with febrifugine at 0.05, 0.1, 0.2, 
and 0.5 μg/ml for 14 days. The morphology of the worms and the egg production of 
the female worms were observed simultaneously. In experiment 2, the incubation 
was conducted as in experiment 1, except that the febrifugine concentrations 
were reduced to 0.005, 0.01, and 0.02 μg/ml. In addition, S. mansoni adult worms 
were incubated with either 0.5 μg/ml febrifugine or none as a control for 5 days 
and stained with neutral red dye.
RESULTS: Febrifugine significantly reduced the survival of S. mansoni male and 
female worms at concentrations of 0.02-0.5 μg/ml following incubation for 14 
days and remarkably inhibited the daily egg output of the female worms. The 
non-treated male and female worms remained morphologically normal within the 
period of 14 days, whereas male and female worms treated with febrifugine at 
different concentrations gradually twisted and subsequently died. In addition, 
S. mansoni adult worms were incubated with either 0.5 μg/ml febrifugine or none 
as a control for 5 days and stained with neutral red dye. Non-treated male worms 
were morphologically normal and stained dark red with neutral red, while 
febrifugine-treated male worms appeared similar to those in the control group 
and were stained at a slightly lower level of dark red than the non-treated male 
worms. Non-treated female worms were morphologically normal, and their 
intestinal tract and vitellaria were stained deep red and dark red, 
respectively. In contrast, febrifugine-treated female worms were morphologically 
damaged, and their intestinal tract and vitellaria remained mostly unstained and 
stained dark red, respectively.
CONCLUSION: Febrifugine exerts potent antischistosomal effects and can be 
expected to contribute to the development of a novel antischistosomal drug.