Cytotoxic and apoptosis-inducing effects of Sutherlandia frutescens in neuroblastoma cells

Background: Sutherlandia frutescens (S. frutescens) is a shrub with attractive flowers used traditionally by in South African to treat a variety of health conditions. Its anti-cancer activity has been reported in a number of cancers, and accordingly, this study was designed to investigate the cytotoxic activity and apoptosis-inducing effects of S. frutescens in neuroblastoma cells, a type of childhood cancer and a leading cause of death in children. Method: In this study, the effect of S. frutescens on cell viability and survival of SKNBE(2) and SHSY5Y neuroblastoma cells was determined using the MMT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide) cell viability assay and clonogenic assay respectively. Furthermore, flow cytometry was used to investigate the accumulation of intracellular reactive oxygen species (ROS) as well as loss of mitochondrial membrane potential (MMP). Caspase-9 activation was also used to detect apoptosis in these cells. Results: The results from this study show that exposure of S. frutescens to SKNBE(2) and SHSY5Y cells led to the inhibition of cell viability and survival and also induced apoptosis, increased intracellular accumulation of ROS and triggered a loss of MMP in these cells. Conclusion: Findings from this study validate folkloric claims on S. frutescens and demonstrate that this plant might serve as a potential anti-cancer agent in neuroblastoma cells, thus providing the rationale for further investigations into the bioactive components eliciting these activities. Keywords: Neuroblastoma, Sutherlandia frutescens , Apoptosis, Reactive oxygen species, Mitochondrial membrane potential