O tratamento com óleo resina de Copaifera multijuga em células trofoblásticas humanas vilosas (Linhagem BeWo) infectadas por Toxoplasma gondii reduz o parasitismo

Abstract

The infection caused by the protozoan Toxoplasma gondii takes on a serious character in pregnant women, causing congenital toxoplasmosis, which consists of the transplacental passage of the tachyzoite forms of the parasite. Treatment is hampered by the toxicity presented by conventional drugs, so other compounds have been evaluated as an alternative treatment for this infection. Medicinal plants, as well as their isolated bioactive compounds, have been extensively tested to combat human parasites. In this context, previous studies have demonstrated the importance of plants of the genus Copaifera for the treatment of parasitic infectious diseases, such as Chagas disease, leishmaniasis and malaria; however, there are still few studies that demonstrate its antiparasitic activity against T. gondii. Therefore, the aim of this study was to investigate the action anti-T gondii from resin oil and ethanolic extract from leaves of Copaifera multijuga. To evaluate the in vitro effect of C. multijuga, villous human trophoblastic cells (BeWo lineage) were used as a host cell model. Firstly, the cytotoxicity of the treatment with resin oil and the ethanolic extract in different concentrations (256, 128, 64, 32, 16, 8 and 4μg/mL) was evaluated using MTT assays. Our data showed that only the highest concentrations were toxic to the cells. Then, BeWo cells were infected and treated or not with the non-toxic concentrations of 64, 32, 16, 8 and 4μg/mL of the resin oil and 128, 64, 32, 16, 8 and 4μg/mL of the ethanolic extract of the leaves and the intracellular proliferation index of the parasite was analyzed by the β-galactosidase assay. As a positive control of parasitism inhibition, the cells were treated with the combination of sulfadiazine and pyrimethamine (SDZ + PIR) (200+8μg/mL, respectively). Interestingly, our results demonstrated that the resin oil reduced the intracellular proliferation of the parasite in the highest concentrations tested, which were more efficient when compared to SDZ + PIR. On the other hand, the ethanolic extract was not able to inhibit parasitism in the evaluated doses. Moreover, we demonstrated that the resin oil at a concentration of 64μg/mL inhibited parasitic invasion, and maintained its antiproliferative effect, even 24 hours after removal of the treatment. Thus, our results highlight the potential of C. multijuga resin oil as an alternative source for the treatment of congenital toxoplasmosis, by reducing the rate of T. gondii proliferation with low cytotoxic effects for host cells.