In vitro antioxidant and anti-proliferative activity of Ethiopian medicinal plant extracts

• Dodonaea angustifolia and Rumex nepalensis exhibited significant antioxidant effect.
• Antioxidant activity of extracts positively correlated with total phenolic content.
• Verbascum sinaiticum demonstrated the most promising selective cytotoxic activity.
• Low toxicity of extracts suggests their use in food and pharmaceutical products.

Identification and characterization of natural products with antioxidant and anti-proliferative activity has received much interest over the past few years. Ethiopia is one of the developing countries which have enormous diversity of plants and yet majority stays scientifically neglected and undiscovered. In this study, the ethanol extracts of 18 Ethiopian wild medicinal plants were investigated for their in vitro antioxidant and anti-proliferative potential. For this purpose DPPH (2,2-diphenyl-1-picrylhydrazyl), ORAC (oxygen radical absorbance capacity) and TPC (total phenolic content) assays together with MTT cell viability assay (performed on Hep-G2 and MRC-5) were used. Extracts of Carissa spinarum, Dodonaea angustifolia, Jasminum abyssinicum, Rumex nepalensis, Rubus steudneri and Verbascum sinaiticum exhibited the most significant results. However, it was discovered that C. spinarum, J. abyssinicum and R. steudneri possessed considerable toxicity against normal MRC-5 cell line. Only extracts of D. angustifolia and R. nepalensis demonstrated significant combinatory antioxidant/anti-proliferative effect, while V. sinaiticum showed best selective anti-proliferative activity. Since aforementioned extracts also exerted low or minimal toxicity to normal cells, we suggest these as prospective material for further development of novel plant-based agents effective against oxidative stress related diseases.