THE ANTI - PROLIFERATIVE AND ANTIOXIDANT ACTIVITY OF FOUR INDIGENOUS SOUTH AFRICAN PLANTS

Background: Cancer is a major cause of death worldwide. Limitations of current cancer therapies necessitate the search for new anticancer drugs. Plants represent an immeasurable source of bioactive compounds for drug discovery. The objective of this study was to assess the anti-proliferative and antioxidant potential of four indigenous South African plants commonly used in traditional medicine. Materials and Methods: The anti-proliferative activity of the plant extracts were assessed by the 2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2 H -Tetrazolium-5-Carboxanilide (XTT) assay on A431; HaCat; HeLa; MCF-7 and UCT-Mel 1 cells and sulforhodamine-B (SRB) assay on HCT-116 and HCT-15 cell lines. Antioxidant activity was determined using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and superoxide scavenging assays. Results: Three of the plant extracts ( Combretum mollefruit , Euclea crispa subsp. crispa leaves and stems and Sideroxylon inerme leaves and stems showed anti-proliferative activity on the A431 cells with IC 50 values ranging between 26.9 - 46.7 μg/ml. The Euclea crispa subsp. crispa extract also showed anti-proliferative activity on the MCF-7 cell line (45.7 μg/ml). All of the plant extracts ( Combretum molle leaves and fruit, Euclea crispa subsp. crispa leaves and stems, Sideroxylon  inerme leaves and stems and Terminalia prunioides leaves and stems) showed DPPH scavenging activity with IC 50 values ranging from 1.8 μg/ml to 11.5 μg/ml. Conclusion: These results indicate that the active extracts of Combretum molle , Euclea crispa subsp. Crispa and Sideroxylon inerme warrant further investigation to determine the mechanism of anti-proliferative activity against cancerous cells. These plant extracts also show potential for further evaluation in the prevention and treatment of cancer. Keywords: South African plants, Traditional medicine, Anti-proliferative activity, Antioxidant activity