O extrato hidroetanólico das folhas de Simarouba versicolor A. St.-Hil. induz citotoxicidade seletiva em células leucêmicas Jurkat mediante parada do ciclo celular e apoptose

Abstract

Simarouba versicolor A. St. –Hil. (Simaroubaceae), is a native and non-endemic tree from Brazil, known at the microregion of Norte Araguaia, Mato Grosso as mata-menino. From a primary screening carried out in our laboratory, using native plants from Mato Grosso state, Simarouba versicolor was chosen. This work aimed to evaluate the cytotoxic potential of the hydroethanolic leaf extract of S. versicolor (EHSv) in Jurkat cells. For this, the selectivity, the effect on cell cycle, and the type of cell death, induced by EHSv in vitro in Jurkat and peripheral blood mononuclear cells (PBMC), were determined. The EHSv was prepared by macerating the leaf powder in a 70% hydroethanolic solution (1:10 w / v). The cytotoxic activity of EHSv was evaluated by concentrations ranging from 0.78 to 200 µg / mL at 24 h, 48 h, and 72 h, using the colorimetric resazurin assay. An IC50 <30 g / mL was considered as cytotoxic for Jurkat cells. Additionally, it was evaluated whether EHSv had selective cytotoxicity for Jurkart cells, through the determination of the selectivity index. The action of EHSv at CI20 and CI50 for the cell cycle in Jurkat and PBMC cells was also evaluated, expressing the results as the percentage of viable cells for each cell cycle phase (G0 \G1, G2\M and S) and for those who did apoptosis. The apoptotic cell death induced by EHSv (IC50) in Jurkat cells was confirmed by testing the union of externalized phosphatidylserine to Annexin- V. After treatment with EHSv in Jurkart cells, the 50% inhibitory concentrations were 38.59 ± 1.31; 15.64 ± 1.15 and 10.26 ± 1.16 at 24, 48 and 72 h, respectively. EHSv was not cytotoxic to PBMC, with a selectivity index for Jurkat (IS) ≥ 4 at all times tested. At the CI20 and CI50, from EHSv, a cell cycle arrest in G1/S was revealed within 24 hours, and this arrest was maintained through the other analyzed times (48 h and 72 h). The EHSv treatment showed 33.5% of cells with fragmented DNA, in the subG0 fraction, in addition to a high amount of Annexin-V + / IP- cells, which are indicative of an apoptotic cell death induction. With the findings from our study, we can conclude that EHSv has potential antitumoral activity for the jurkat cell line, with great selectivity, being the cytotoxicity induced by cell cycle arrest and apoptosis. However, complementary tests are needed to elucidate the mechanism of action, which resulted in this cell cycle arrest and apoptosis, as well as the possible substances involved in this effect.