Cytotoxic effects of an extract containing alkaloids obtained from Prosopis juliflora Sw. D.C. (Algaroba) pods on glioblastoma cells

Abstract

Prosopis juliflora is largely used for feeding dairy and beef cattle. However, this plant has been found to cause neurotoxic disease when it is the sole sustenance for the animal. In the central nervous system (CNS), the glial cells are essential in maintaining neuronal cell health and integrity. In this study, an extract containing alkaloids (AE) from P. juliflora pods was obtained and tested on glial cells of the lineage GL-15 to investigate: cell cytotoxicity, morphological changes and the expression of GFAP, a marker of astrocytic reactivity. Concentrations between 0.03-30μg/ml of AE were assayed for 24-72h. The MTT test, LDH activity, and Trypan blue assay revealed dose-dependant cytotoxicity for GL-15 cells. Growth curves designed using Trypan blue staining displayed significant reduction (p<0.05) of the number of viable GL-15 cells, which reached maximum effect at 30μg/ml of AE. Immunocytochemistry and western blotting assay performed for the cytoskeletal proteins, vimentin and GFAP, revealed expression of vimentin in GL-15 cells at the lowest concentration (0.03μg/ml), and a change on their morphology together with an increase of the number of the GFAP positive cells. These effects were not detected when the highest concentrations (3- 30μg/ml) were tested. The results suggest that the extract containing alkaloids may be involved in the phenotypical modifications detected on the lineage studied, in the expression of the cytoskeletal proteins, and in the reduction of the viable cell number.