Comparative studies on the in vitro antioxidant properties of methanolic and hydro-ethanolic leafy extracts from eight edible leafy vegetables of Ghana

Abstract

Epidemiological studies indicate that consumption of fruits and vegetables has the ability to inhibit the damaging activities of free radicals in the human body. Eight edible leafy vegetables of Ghana namely: Xanthosoma sagittifolium, Hibiscus Sabdariffa, Solanum macrocarpon, Talinum triangulare, Corchorus olitorius,Laportea aestuans, Ipomoea batatas, and Amaranthus cruentus were assessed for their antioxidant properties. The experimental results indicate that hydro-ethanol is an effective solvent for extracting the phytoconstituents of the leafy vegetables. The total antioxidant capacity (TAC) and total phenol content (TPC) in the methanol extracts (METE) and hydro-ethanol extracts (HETE) from the selected leafy vegetables within the measured concentration range (0.1 - 3.0 mg/ml) decreased in the order X. sagittifolium > I. batatas > L. aestuans > T. Triangulare > H. Sabdariffa > C. olitorius > S. macrocarpon > A. cruentus. A high and positive correlation was observed between TPC and TAC in both the METE and HETE from all the selected leafy vegetables. The selected leafy vegetables showed strong antioxidant properties with respect to their free radical scavenging activity and Fe3+ reduction ability with hydro-ethanol extracts indicating higher antioxidant potential compared with their respective methanol extracts.   Key words: Hydro-ethanol extract, 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity, total antioxidant capacity, reducing power, edible leafy vegetables.