In vitro and in vivo trypanocidal action of aescin and aescin liposomes against Trypanosoma evansi in experimental mice

Objective: To verify the trypanocidal effectiveness of aescin and aescin liposomes against Trypanosoma evansi in vitro and in vivo. Methods: Aescin and aescin liposomes were used in vitro on trypomastigotes at different concentrations (0.5%, 1.0% and 2.0%) and exposure times (0, 1, 3, 6 and 9 h). In vivo tests were performed using mice as the experimental model. Trypanosome evansi infected mice were treated with aescin and aescin liposomes with doses of 60 and 100 mg/kg during 4 d. Results: The three concentrations tested in free form and nanoencapsulated showed trypanocidal activity in vitro, completely eliminating the parasites in small concentration after 6 h of assay. Animals treated with aescin (100 mg/kg) and aescin liposomes (100 mg/kg) showed increase in longevity, however without curative effect. Conclusions: Active compounds present in natural products, such as aescin, may potentiate the treatment of trypanosomosis when used in association with other trypanocidal drugs.

In Vitro Trypanocidal Activity of Macela (Achyrocline satureioides) Extracts against Trypanosoma evansi

The aim of this study was to verify the trypanocidal effectiveness of aqueous, methanolic, and ethanolic extracts of Achyrocline satureioides against Trypanosoma evansi in vitro. A. satureioides extracts, known as macela, were used on trypomastigotes at different concentrations (1, 5, 10, 50, 100, 500, and 1,000 microg/ml) and exposure times (0, 1, 3, 6, and 9 hr). A dose-dependent effect was observed when the 3 extracts were tested. The concentrations of 1, 5, and 10 microg/ml were not able to kill trypomastigotes until 3 hr after exposure, and the highest concentrations (500 and 1,000 microg/ml) were able to kill all trypomastigotes after 1 hr. When the time of exposure was increased up to 9 hr, the concentrations at 50 and 100 microg/ml were 100% effective to 3 extracts. The chemical analysis of the extracts revealed the presence of flavonoids, a trypanocidal compound already described. Based on the results, we can conclude that the A. satureioides extracts exhibit trypanocidal effects.

Influence of Toxoplasma gondii Acute Infection on Cholinesterase Activities of Wistar Rats

Several studies have shown the mechanisms and importance of immune responses against Toxoplasma gondii infection and the notable role of cholinesterases in inflammatory reactions. However, the association between those factors has not yet been investigated. Therefore, the aim of this study was to evaluate the acetylcholinesterase (AChE) activity in blood and lymphocytes and the activity of butyrylcholinesterase (BChE) in serum of rats experimentally infected with T. gondii during the acute phase of infection. For that, an in vivo study was performed with evaluations of AChE and BChE activities on days 5 and 10 post-infection (PI). The activity of AChE in blood was increased on day 5 PI, while in lymphocytes its activity was enhanced on days 5 and 10 PI (P<0.05). No significant difference was observed between groups regarding to the activity of BChE in serum. A positive (P<0.01) correlation was observed between AChE activity and number of lymphocytes. The role of AChE as an inflammatory marker is well known in different pathologies; thus, our results lead to the hypothesis that AChE has an important role in modulation of early immune responses against T. gondii infection.