Activity in vitro and in vivo against Trypanosoma cruzi of a furofuran lignan isolated from Piper jericoense.

Piperaceae species are abundant in the tropics and are important components of secondary vegetation. Many of these plants have received considerable attention due to their wide range of biological activities. Here, the trypanocidal activity of extracts and fractions with different polarities obtained from Colombian Piper jericoense plant was evaluated. A furofuran lignan, (1S,3aS,4S,6aS)-1-(3',4'-dimethoxyphenyl)-4-(3″,4″-methylendioxyphenyl)hexahydrofuro[3,4-c]furan, (1), was isolated from Colombian Piper jericoense leaves ethyl acetate extract. Its relative configuration at the stereogenic centers was established on the basis of various spectroscopic analyses, including 1D- (1H, 13C, and DEPT) and 2D-NMR (COSY, NOESY, HMQC and HMBC) and a 2D INADEQUATE NMR experiment as well as by comparison of their spectral data with those of related compounds such as (+)-Kobusin (2). The activity against Trypanosoma cruzi indicated that compound 1 was active against all parasite forms (epimastigote, amastigote and trypomastigote) and presented lower toxicity than the reference drug, benznidazole (Bz), evidenced by a selective index of 18.4 compared to that of Bz, which was 6.7. Moreover, this compound inhibited the infectious process, and it was active in infected mice in the acute phase. This compound significantly inhibited the T. cruzi Fe-SOD enzyme, whereas Cu/Zn-SOD from human cells was not affected. Ultrastructural analyses, together with metabolism-excretion studies in the parasite, were also performed to identify the possible mechanism of action of the tested compound. Interestingly, the lignan affected the parasite structure, but it did not alter the energetic metabolism.

Scorpiand-like azamacrocycles prevent the chronic establishment of Trypanosoma cruzi in a murine model.

Chagas disease is today one of the most important neglected diseases for its upcoming expansion to non-endemic areas and has become a threat to blood recipients in many countries. In this study, the trypanocidal activity of ten derivatives of a family of aza-scorpiand like macrocycles is evaluated against Trypanosoma cruzi in vitro and in vivo murine model in which the acute and chronic phases of Chagas disease were analyzed. The compounds 4, 3 and 1 were found to be more active against the parasite and less toxic against Vero cells than the reference drug benznidazole, 4 being the most active compound, particularly in the chronic phase. While all these compounds showed a remarkable degree of inhibition of the Fe-SOD enzyme of the epimastigote forms of T. cruzi, they produced a negligible inhibition of human CuZn-SOD and Mn-SOD from Escherichia coli. The modifications observed by (1)H NMR and the amounts of excreted catabolites by the parasites after treatment suggested that the mechanism of action could be based on interactions of the side chains of the compounds with enzymes of the parasite metabolism. The ultrastructural alterations observed in treated epimastigote forms confirmed that the compounds having the highest activity are those causing the largest cell damage. A complementary histopathological analysis confirmed that the compounds tested were significantly less toxic to mammals than the reference drug.

In vitro and in vivo studies of the trypanocidal activity of four terpenoid derivatives against Trypanosoma cruzi.

Four terpenoid derivatives were examined for their activity against Trypanosoma cruzi. Our results show that two compounds were very active in vitro against both extra- and intracellular forms. These compounds, non-toxic for the host cells, are more effective than the reference drug benznidazole. The capacity to infect cells was negatively affected and the number of amastigotes and trypomastigotes was reduced. A wide range of ultrastructural alterations was found in the epimastigote forms treated with these compounds. Some metabolic changes occurred presumably at the level of succinate and acetate production, perhaps caused by the disturbance of the enzymes involved in sugar metabolism inside the mitochondria. In vivo results were consistent with those observed in vitro. The parasitic load was significantly lower than in the control assay with benznidazole. The effects of these products showed the reduction of the anti-T. cruzi antibodies level during the chronic stage.

In vitro and in vivo trypanosomicidal activity of pyrazole-containing macrocyclic and macrobicyclic polyamines: their action on acute and chronic phases of Chagas disease.

The in vitro and in vivo anti- Trypanosoma cruzi activity of the pyrazole-containing macrobicyclic polyamine 1 and N-methyl- and N-benzyl-substituted monocyclic polyamines 2 and 3 was studied. Activity against both the acute and chronic phases of Chagas disease was considered. The compounds were more active against the parasite and less toxic against Vero cells than the reference drug benznidazole, but 1 and 2 were especially effective, where cryptand 1 was the most active, particularly in the chronic phase. The activity results found for these compounds were complemented and discussed by considering their inhibitory effect on the iron superoxide dismutase enzyme of the parasite, the nature of the metabolites excreted after treatment, and the ultrastructural alterations produced. A complementary histopathological analysis confirmed that the compounds tested were significantly less toxic to mammals than the reference drug and that 1 and 2 exhibited lower levels of damage than 3.

In vivo trypanosomicidal activity of imidazole- or pyrazole-based benzo[g]phthalazine derivatives against acute and chronic phases of Chagas disease.

The in vivo trypanosomicidal activity of the imidazole-based benzo[g]phthalazine derivatives 1-4 and of the new related pyrazole-based compounds 5 and 6 has been studied in both the acute and chronic phases of Chagas disease. As a rule, compounds 1-6 were more active and less toxic than benznidazole in the two stages of the disease, and the monosubstituted derivatives 2, 4, and 6 were more effective than their disubstituted analogs. Feasible mechanisms of action of compounds 1-6 against the parasite have been explored by considering their inhibitory effect on the Fe-SOD enzyme, the nature of the excreted metabolites and the ultrastructural alterations produced. A complementary histopathological analysis has confirmed that the monosubstituted derivatives are less toxic than the reference drug, with the behavior of the imidazole-based compound 4 being especially noteworthy.