Apoptosis-inducing effects of Tulbaghia violacea Harv methanolic extracts on human Jurkat leukemia T cells

The aim of the present study was to investigate the effects of methonolic extracts of Tulbaghia violacea (TVL), on Jurkat cells (human T lymphocyte). Jurkat cells were treated with IC50 concentrations of TVL (leaf, rhizome and stalk) extracts as determined by MTT assay and glutathione (GSH) concentration was measured using the GSH-Glo assay. The comet and DNA fragmentation assays were used to determine DNA damage induced by the TVL extracts, and mitochondrial membrane potential activity performed by JC-1assay. The results showed that all TVL extracts except leaf increased apoptosis. TVL leaf instead showed increased necrosis when compared to other TVL components. In addition, TVL extracts induced caspase 3/7, 8 and 9 activity and induced PARP cleavage. These findings suggest that TVL exerts anti-cancer activity primarily through the mechanism of apoptosis. The results suggest that TVL rhizome and stalk induce apoptosis through the intrinsic pathway due to increased activation of caspase 9 and 3/7, with TVL rhizome having the greatest effect on human T lymphocyte cells. Thus, this study suggest that TVL extracts have the potential to induce cell death in Jurkat cells by mitochondria mediated pathway through the involvement of caspase-3/7 in particularly in TVL rhizome.