Distribution of total phenolics and antioxidant activity in fruit, leaf, stem and root of Monsonia burkeana

Monsonia burkeana, widely used as ‘special tea’, is harvested unsustainably due to insufficient information on the accumulative abilities of its organs on the secondary metabolites. Using phenolics and antioxidants as focus chemical compounds, an investigation was carried out to (1) determine the accumulative abilities of organs of M. burkeana on phenolic and antioxidant compounds, and (2) determine whether phenolic acids and antioxidants in M. burkeana had density-dependent relationship patterns. Ten plants per plot, with three replicates, were harvested whole, oven-dried, separated into the four organs and quantified for phenolics and antioxidant components using the Folin Ciocalteau method and the Trolox Equivalent Antioxidant Capacity (TEAC) assay, respectively. Generally, reproductive and vegetative organs had high levels of phenolic and antioxidant compounds when compared to roots. The saturation factor suggested that more than 90% antioxidants were derivatives of the phenolic compounds. Optimum levels of antioxidant activity were attained at 5.39, 5.49, 4.36 and 4.13 mg/ 100 g of phenolics in fruit, leaf, stem and root, respectively. In conclusion, vegetative and reproductive organs are good sources of phenolic and antioxidant compounds in M. burkeana.