Effects of (-)-6,6'-dinitrohinokinin on adult worms of Schistosoma mansoni: a proteomic analyses

Abstract Schistosomiasis, a chronic disease that affects million people worldwide, is caused by trematode flukes of the genus Schistosoma. The lack of an anti-schistosomiasis vaccine and massive monotherapy with praziquantel reinforces the need for search and development of new therapeutic drugs. Recently, we demonstrated that the essential oil of Piper cubeba L., Piperaceae, and their derivative dibenzylbutyrolactolic (-)-6,6'-dinitrohinokinin, presents in vitro and in vivo activities against Schistosoma mansoni. Here, we identified changes in the protein expression after exposure to dibenzylbutyrolactolic (-)-6,6'-dinitrohinokinin. We applied two-dimensional gel electrophoresis (2-DE) to S. mansoni soluble protein extracts and observed at least 38 spots to be affected by dibenzylbutyrolactolic (-)-6,6'-dinitrohinokinin. We further identified 25 differentially expressed proteins by mass spectrometry. Enrichment for biological processes and predictive analyses of protein-protein interactions suggest that dibenzylbutyrolactolic (-)-6,6'-dinitrohinokinin targets proteins involved mainly in metabolic processes, especially carbohydrate metabolism. In summary, this study provides an interesting approach to understand the anti-parasitic activity of semi-synthetic (-)-6,6'-dinitrohinokinin a derivative compound from lignan and for the development of new therapy strategies.

Anthelmintic effects of the essential oil of fennel (Foeniculum vulgare Mill., Apiaceae) against Schistosoma mansoni.

Foeniculum vulgare Mill. (Apiaceae), known as fennel, is a widespread aromatic herbaceous plant, and its essential oil is used as additive in the food, pharmaceutical, cosmetic, and perfume industries. The in vitro antischistosomal activity and cytotoxic effects against V79 cells of the essential oil of F. vulgare cultivated in southeastern Brazil (FV-EO) was investigated. The FV-EO was obtained by hydrodistillation and characterized by GC-FID and GC/MS analyses. (E)-Anethole (69.8%) and limonene (22.5%) were identified as the major constituents. Its anthelmintic activity against Schistosoma mansoni was evaluated at concentrations of 10, 50, and 100 µg/ml, and it was found to be active against adult S. mansoni worms, although it was less effective than the positive control praziquantel (PZQ) in terms of separation of the coupled pairs, mortality, and decreased motor activity. However, FV-EO elicited an interesting dose-dependent reduction in the number of S. mansoni eggs. On their own, (E)-anethole and the limonene enantiomers were much less effective than FV-EO and PZQ. An XTT-cytotoxicity-based assay evidenced no FV-EO cytotoxicity against V79 cells. In summary, FV-EO displayed moderate in vitro schistosomicidal activity against adult S. mansoni worms, exerted remarkable inhibitory effects on the egg development, and was of low toxicity.

In vitro schistosomicidal effects of the essential oil of Tagetes erecta

The in vitro schistosomicidal effects of the essential oil obtained from Tagetes erecta L. Asteraceae, leaves (TE-EO) collected in Brazil against Schistosoma mansoni worms are reported in this paper. The oil caused a significant decrease in the motor activity at 50 µg/mL as minimal concentration after 24 h. This oil also caused death of all the parasites and the separation of coupled pairs into individual male and female at 100 µg/mL after 24 h. The viability of adult worm groups treated with the TE-EO at 100 µg/mL was similar to that of groups treated with praziquantel (positive control). In addition, the oil promoted the inhibition of eggs development at all the tested concentrations. These data indicate that the TE-EO could be considered as a promising source for the development of new schistosomicidal agents.