Evaluation of the in vitro cytotoxic effects of carvoeiro leaf extracts [Callisthene fasciculata (Spr.) Mart.]

Resumo

Callisthene fasciculata (Spr.) Mart. is a tropical tree belonging to the family Vochysiaceae and is popularly known as carvoeiro. In popular medicine, it is used for the treatment of hepatitis, stomach diseases, kidney problems, jaundice, and anemia; however, its effects have not been scientifically proven. Therefore, the objective of the present study was to conduct a preliminary study on the biological effects of carvoeiro by evaluating its in vitro cytotoxic effect in co-culture with different cell types. To prepare the extract, 70% ethanol (ratio, 1:5) was added to the dried and crushed leaves, which were incubated for 7 days in the dark. Next, the extract was filtered and evaporated in a rotavapor to reduce the volume and obtain a powder. The powder was resuspended in RPMI culture medium supplemented with 20% fetal bovine serum and added to Walker 256 tumor cells or splenic cells (rat or mice) at different concentrations (serial dilutions of 1000 μg/ml to 7.81 μg/ml). After 24 h, cytotoxicity analysis was performed by the colorimetric MTT reduction assay. The results demonstrated that the extract favored the viability of tumor and rat spleen cells at higher concentrations (Walker tumor: 1000 μg/ml, 0.685 ± 0.066, 500 μg/ml, 0.565 ± 0.067; 250 μg/ml, 0.329 ± 0.019; control, 0.168 ± 0.01; rat spleen: 1000 μg/ml, 0.334 ± 0.045; control: 0.219 ± 0.053) and showed a cytotoxic effect at lower concentrations, with the percentage of cell inhibition ranging from 7% to 19%. According to the results, we concluded that the leaf extract of Callisthene fasciculata (Spr.) Mart had a direct effect on the studied cells in vitro. This was the first study to report the biological effect of this plant; however, further study is needed to determine its effects on complex systems, such as those found in vivo.