In vitro and in vivo evaluation of six artemisinin derivatives against Schistosoma mansoni

Schistosomiasis is a tropical neglected disease whose socioeconomic impact is surpassed only by malaria. Until recently, praziquantel (PZQ) has been the only available drug, raising concerns that tolerant/resistant strains may appear. Since the discovery of the schistosomicidal potential of artemisinin (ART), new derivatives have been produced and evaluated. In this work, we evaluated the activity of ART derivatives against Schistosoma mansoni, both in vitro and in vivo. In the in vitro assay, worm survival, oviposition, and morphological alterations were evaluated. Further analysis of morphological alterations and membrane integrity was conducted using scanning electron microscopy and a cell-permeable, benzimidazole dye (Hoescht 33258) that binds to the minor groove of double stranded DNA. For the in vivo assay, artesunic acid (AcART) and dihydroartemisinin acetate (AcDQHS) were selected, since they showed the best in vitro results. Infected mice treated 21, 45, or 60 days post-infection (dpi), with a concentration of 100 mg/kg of either AcART or AcDQHS, showed a significant worm reduction (particularly in females), fewer eggs eliminated in feces, and a decrease of immature eggs in the intestinal tissues. Our results indicate that AcART and AcDQHS have some schistosomicidal activity against juvenile and adult stages of S. mansoni.