antioxidants Article The Implication of Chemotypic Variation on the Anti-Oxidant and Anti-Cancer Activities of Sutherlandia frutescens (L.) R.Br. (Fabaceae) from Different Geographic Locations Samkele Zonyane 1, Olaniyi A. Fawole 2,3 , Chris la Grange 1, Maria A. Stander 4 , Umezuruike L. Opara 2 and Nokwanda P. Makunga 1,* 1 Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Merriman Avenue, Stellenbosch 7602, South Africa;
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[email protected] (C.l.G.) 2 South African Research Chair in Postharvest Technology, Department of Horticultural Science, Stellenbosch University, Private Bag X1, Merriman Avenue, Stellenbosch 7602, South Africa;
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[email protected] (U.L.O.) 3 Department of Botany and Plant Biotechnology, University of Johannesburg, P.O. Box 524, Auckland Park, Johannesburg 2006, South Africa 4 Central Analytical Facility, Stellenbosch University, Private Bag X1, Merriman Avenue, Stellenbosch 7602, South Africa;
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[email protected]; Tel.: +27-21-808-3061 Received: 17 January 2020; Accepted: 1 February 2020; Published: 13 February 2020 Abstract: Extracts of Sutherlandia frutescens (cancer bush) exhibit considerable qualitative and quantitative chemical variability depending on their natural wild origins. The purpose of this study was thus to determine bioactivity of extracts from different regions using in vitro antioxidant and anti-cancer assays. Extracts of the species are complex and are predominantly composed of a species-specific set of triterpene saponins (cycloartanol glycosides), the sutherlandiosides, and flavonoids (quercetin and kaempferol glycosides), the sutherlandins. For the Folin-Ciocalteu phenolics test values of 93.311 to 125.330 mg GAE/g DE were obtained.