Antioxidant properties, macro and micro elements of selected edible vegetables

Abstract

Background: Many green leafy vegetables (GLV) have been shown to have  significant antioxidant activity which may be an important property of medicinal plants associated with the treatment of several diseases. Trace element plays a crucial role in the medicinal value of a plant, in health and to cure disease. They play a nutritive, catalytic and balancing function in plants and animals, since animals  easily consume these minerals through food.
Objective: The aim of this work is to quantify the macro and trace elements present in these vegetables in order to determine their contribution to the daily dietary  requirement and also determine those element that are present in excess of their maximum dietary allowance.
Methodology: The elemental composition and antioxidant activities of ten common edible vegetables obtain from a market in Ibadan, Nigeria were analyzed using  atomic absorption spectroscopy and DPPH radical scavenging assay.
Result: Three macro elements and seven trace elements were determined. The  vegetables samples were found to contain trace elements such as manganese, iron, copper, cobalt, chromium (Mn, Fe, Cu, Zn, Co, Cr). Telfaria occidentalis, one of the most widely eaten vegetables has the best profile for macro elements with a  concentration of 364.2±1.1 mg/g for Ca, 55.4±1.3 mg/g for Mn and 365.6±0.3 mg/g for K. It also had a concentration of 1185.0±0.8 mg/g for Fe.
Conclusion: Only one of the vegetables was found to accumulate lead in excess of maximum daily intake. All vegetables were found to be rich in many of the essential elements and all vegetables exhibited varying degree of antioxidant capacity with Gnetum africanum (Gnetaceae) having the highest radical scavenging activity of 14.58 ± 1.8 μg/mL .

Keywords: Macro elements, Trace elements, DPPH radical scavenging, Edible  vegetable