Abstract
The leaves of Justicia insularis have been generating a lot of interest among the Yoruba people in the Southern Nigeria. They provide useful source of human nutrition and medicinal value. In this study, J. insularis leaves were harvested, processed and analysed to determine their chemical compositions and also to investigate their antioxidant properties. The proximate analysis showed that the sample contained 15.955% ash, 4.48% crude protein, 2.144% lipid and 18.367MJ/kg energy. The contents of calcium, potassium, phosphorous and magnesium were 3.30, 1.68, 0.11, and 0.76, respectively, while the amounts of sodium, manganese, iron, copper and zinc were 631.04, 334.02, 4490.08, 6.31 and 49.72 mg/g, respectively. The free radical scavenging activity of ethanol extract of J. insularis was determined by three methods namely: scavenging effect on 2,2-diphenyl-1-picryhydrazyl radical (DPPH), hydroxyl radical and peroxide oxidation. Comparison of the results obtained with the three antioxidant standards used in the assay revealed that the ethanol extract of the plant possessed antioxidant activity. The results obtained revealed high value of iron in the leaf and free radical scavenging properties indicating the presence of primary antioxidants in the plant.
Key words: Antioxidants, chemical composition, free radical, Justicia insularis
