ABSTRACT
ABSTRACT Euphorbia umbellata (Pax) Bruyns, Euphorbiaceae, is commonly used in folk medicine of southern Brazil to treat several kinds of cancer. The latex (part of the plant used for this purpose) is mixed with water and taken as treatment; but this matrix contains toxic potential related to the presence of some phorbol type diterpenes. So the aim of this study was to evaluate the cytotoxicity of the crude extract of the bark of E. umbellata and its fractions (Hex, CHCl3, EtOAc and MeOH) using in vitro assay (applying Jurkat cells line). A preliminary cytotoxic study (MTT reduction, trypan blue exclusion and DNA quantification assays) was executed to identify the most active material. The CHCl3 fraction displayed the highest activity and was selected for further investigation of any cytotoxic mechanism and evaluation of chemical composition; flow cytometry, Acridine orange and Hoechst 33342 staining experiments and Gas chromatography–mass spectrometry analysis were applied to achieve these results. This fraction demonstrated the best cytotoxic results against Jurkat cells line with IC50 of 29.00 ± 1.49, 10.06 ± 1.48 and 4.83 ± 2.25 µg/ml for 24, 48 and 72 h of experiment, respectively (trypan blue exclusion). The mechanism responsible for this action can be associated with the promotion of cell cycle arrest and apoptosis. The two main classes of compounds present in the CHCl3 fraction are steroids and triterpenes. Further, phytochemical studies with this fraction need to be evaluated, to try isolating these substances and establishing a more detailed cytotoxic study against Jurkat cells.