Preliminary cytotoxic activity of sutherlandia frutescens and carpobrotus edulis on malignant glioblastoma cells

Glioblastoma (GBM) is the most common and aggressive intracranial tumour with limited therapeutic options due to their high tumour vasculature and invasiveness. Treatment of GBM includes surgery, followed by chemotherapy and radiotherapy. Despite these treatment options, tumour relapse is still a major issue hence the need for cheap and effective treatment strategies. South Africa is endowed with numerous medicinal plants including Sutherlandia frutescens (S. frutescens) and Carpobrotus edulis (C.edulis), which has been previously reported for their antioxidant and neuroprotective activities. Accordingly, this study was designed to investigate the cytotoxicity of both medicinal plants (S. frutescens and C. edulis) in malignant human GBM cells U251 and U87. The cytotoxic activity was measured using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide (MTT) assay while the effect of extracts on colony formation and survival was determined using clonogenic assay. Results show that both S. frutescens and C .edulis induced cytotoxicity in both GBM cells and inhibit colony formation in U251 cells. These findings show that extracts from these plants may be useful in the treatment of GBM and thus requires further investigations into their mechanisms of action as well as isolation of bioactive components responsible for these activities.