Schistosomiasis, a parasitic disease caused by trematode flatworms of the genusSchistosoma, affects more than 200 million people worldwide, and its control is dependent on a single drug, praziquantel.Tanacetum vulgare(Asteraceae) is used in folk medicine as a vermifuge. This study aimed to investigate thein vitroschistosomicidal activity of the crude extract (TV) and the essential oil (TV-EO) from the aerial parts ofT. vulgare. TV-EO was obtained by hydrodistillation and analyzed by GC/MS, which allowed the identification ofβ-thujone (84.13%) as the major constituent. TV and TV-EO, at 200 μg/mL, decreased motor activity and caused 100% mortality of all adult worms. At 100 and 50 μg/mL, only TV caused death of all adult worms, while TV-EO was inactive. TV (200 μg/mL) was also able to reduce viability and decrease production of developed eggs. Confocal laser scanning microscopy showed morphological alterations in the tegument of theS. mansonisurface after incubation with TV (50 and 100 μg/mL). Quantitative analysis on the schistosomes tegument showed that TV caused changes in the numbers of tubercles ofS. mansonimale worms in a dose-dependent manner. The findings suggest thatT. vulgareis a potential source of schistosomicidal compounds.

SUMMARY: Evolutionary and closer structural relationships are demonstrated by phylogenetic analysis, peptide prediction and molecular modelling betweenSolanum tuberosumapyrase,Schistosoma mansoniSmATPase 2 andLeishmania braziliensisNDPase. Specific protein domains are suggested to be potentially involved in the immune response, and also seem to be conserved during host and parasite co-evolution. Significant IgG antibody reactivity was observed in sera from patients with American cutaneous leishmaniasis (ACL) and schistosomiasis using potato apyrase as antigen in ELISA.S. mansoniadult worm or egg,L. braziliensispromastigote (Lb) andTrypanosoma cruziepimastigote (EPI) have ATP diphosphohydrolases, and antigenic preparations of them were evaluated. In ACL patients, IgG seropositivity was about 43% and 90% for Lb and potato apyrase, respectively, while IgM was lower (40%) or IgG (100%) seropositivity for both soluble egg (SEA) and adult worm (SWAP) antigens was higher than that found for potato apyrase (IgM=10%; IgG=39%). In Chagas disease, IgG seropositivity for EPI and potato apyrase was 97% and 17%, respectively, while the IgM was low (3%) for both antigens. The study of the conserved domains from both parasite proteins and potato apyrase could lead to the development of new drug targets or molecular markers.

The fact that theSchistosoma mansoniegg has two ATP diphosphohydrolase (EC 3.6.1.5) isoforms with different net charges and an identical molecular weight of 63000, identified by non-denaturing polyacrylamide gel electrophoresis and immunological cross-reactivity with potato apyrase antibodies, is shown. In soluble egg antigen (SEA), only the isoform with the lower net negative charge was detected and seemed to be the predominant species in this preparation. By confocal fluorescence microscopy, using anti-potato apyrase antibodies, theS. mansoniegg ATP diphosphohydrolase was detected on the external surface of miracidium and in von Lichtenberg's envelope. Intense fluorescence was also seen in the outer side of the egg-shell, entrapped by the surface microspines, suggesting that a soluble isoform is secreted. ATP diphosphohydrolase antigenicity was tested using the vegetable protein as antigen. The purified potato apyrase was recognized in Western blots by antibodies present in sera from experimentallyS. mansoni-infected mice. In addition, high levels of IgG anti-ATP diphosphohydrolase antibodies were detected by ELISA in the same sera. This work represents the first demonstration of antigenic properties ofS. mansoniATP diphosphohydrolase and immunological cross-reactivity between potato apyrase and sera from infected individuals.

The aims of this work were to evaluate thein vitroandin vivoschistosomicidal properties of the methanolic extract of the aerial parts ofMitracarpus frigidus(MFM) and to determine its HPLC profile. For thein vitroexperiment, four pairs of adult worms, obtained from infected mice, were exposed to different concentrations of MFM (100 to 400 μg/mL) for 24 and 48 h and analyzed under an inverted microscope. For thein vivoexperiment, mice were inoculated with cercariae and, 20 days after infection, MFM (100 and 300 mg/kg) was administered orally for the following 25 days. Mice were euthanized after 60 days. MFM showedin vitroschistosomicidal activity, exhibiting the opening of the gynaecophoral canal of some male schistosomes, the presence of contorted muscles, vesicles, and the darkening of the paired worms skin.In vivoexperiments showed that MFM treatments significantly reduced total worm count, as praziquantel, showing a decrease in liver and spleen weight. Also, a significant reduction in granuloma density was observed. MFM treatment did not cause alterations in the liver function of either infected or noninfected mice. The HPLC chromatogram profile showed the presence of kaempferol-O-rutinoside, rutin, kaempferol, psychorubrin, and ursolic acid.