The biochemical effects of Sutherlandia Frutescens in cultured H9 cancerous T cells and normal human T lymphocytes.
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Indigenous plants have long been used by African populations in their cultural lives and health care. Sutherlandia frutescens (SF) is a popular traditional medicinal plant found in various parts of southern Africa and used for treatment or management of different diseases, including cancer and HIV/AIDS. In this study, the biochemical effects of various dilutions (1/50, 1/150, 1/200, and 1/300) of SF 70% ethanol (SFE) and deionised water (SFW) extracts in cancerous H9 and normal T cells were examined. Untreated, 70% ethanol-treated and camptothecin (CPT, 20jiiM) treated cells were used as reference samples for comparison. Cytotoxicity, apoptotic enzymes activity, oxidant scavenging and antioxidant promoting abilities, cellular morphology and cytokine signalling effects were assessed using the methylthiazol tetrazolium (MTT) assay, adenosine triphosphate (ATP) assay, caspase-3/-7 activity assay, thiobarbituric acid reactant substance (TBARS) and glutathione (GSH) assays, fluorescence microscopy and an ELISAbased cytokine analyses assay respectively. Sutherlandia frutescens ethanol and water extract dilutions (1/50 and 1/200) were shown to be cytotoxic to H9 T cells in a dose- and time-dependent manner with the SFE extract having an average IC50 of 1/40 after 24 hours while SFW extract reached a similar IC50 only after 48 hours. In normal T cells, the SFE extract induced proliferation after 24 hours but this was reverse after 48 hours. The SFW extract dilutions did not significantly change cell viability after 24 hours but significantly increased cell viability after 48 hours. Both SFE and SFW extracts dilutions induced a dose- and time-dependent inhibition of caspase-3/-7 activity in both H9 and normal T cells. Both types of extracts were also shown to efficiently remove lipid peroxides from supernatants of treated cell lines, with SFW extract having a more lasting effect. In the GSH assay, the SFE and SFW extract dilutions reduced GSH levels in H9 T cells, with the SFW extract dilutions being more effective. In normal T cells, the higher dilutions (1/150 and 1/300) of SFW extract increased GSH levels significantly while lower dilutions (1/50) of both SFE and SFW extracts significantly inhibited GSH levels. Lower dilutions (1/50) of SFE and SFW extracts induced chromatin condensation in both H9 and normal T cells after 48 hours incubation. Using treated peripheral blood mononuclear cells (PBMCs) supernatants, SFE and SFW extract dilutions were shown to reduce the levels of pro-inflammatory cytokines IL 1 p and TNF-a in a dose-dependent manner. These results further confirmed the anticancer abilities of SF and showed that higher concentrations of this medicinal plant can be toxic to normal T cells in vitro while lower concentrations can stimulate the immune cells. Therefore further studies should be conducted with regards to the effects of SF on the immune system in both in vitro and in vivo systems.