Research Article Evaluation of Nitrite Radical Scavenging Properties of Selected Zimbabwean Plant Extracts and Their Phytoconstituents Fadzai Boora, 1 Elaine Chirisa, 2 and Stanley Mukanganyama 2,3 1 School of Pharmacy, College of Health Sciences, University of Zimbabwe, Mt. Pleasant, Harare, Zimbabwe 2 Department of Biochemistry, University of Zimbabwe, Mt. Pleasant, Harare, Zimbabwe 3 Biomolecular Interactions Analyses Group, Department of Biochemistry, University of Zimbabwe, P.O. Box MP 167, Mt. Pleasant, Harare, Zimbabwe Correspondence should be addressed to Stanley Mukanganyama; smukanganyama@medic.uz.ac.zw Received 6 December 2013; Accepted 4 March 2014; Published 6 April 2014 Academic Editor: Vassiliki Oreopoulou Copyright © 2014 Fadzai Boora et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Oxidative stress resulting from accumulation of reactive oxygen species has been associated with disease. Te search for natural antioxidants of plant origin is necessitated by the side efects associated with synthetic antioxidants currently available. Te objective of the study was to determine the antioxidant activity of Combretum zeyheri, Combretum platypetalum, and Parinari curatellifolia extracts by determining nitrite radical scavenging ability. Te nitrite radical scavenging assay was used to evaluate the antioxidant potential of the extracts. Te total favonoid content of P. curatellifolia methanol extract was determined by the aluminium calorimetric method. Te aqueous and ethanolic leaf extracts of C. zeyheri, C. platypetalum, and P. curatellifolia extracts exhibited nitrite radical scavenging activity. Te results show the scavenging activity in the order of potency: P. curatellifolia > C. platypetalum > C. zeyheri with concentration values of 103 g/mL, 158 g/mL, and 188 g/mL for the ethanol extracts and 92.5 g/mL, 97.5 g/mL, and 198 g/mL for the water extracts, respectively. P. curatellifolia ethanol extract was the most potent and the total favonoid content was estimated to be 0.4 ± 0.05 mg/g quercetin and could account for the activity. Tus, our fndings provide evidence that C. zeyheri, C. platypetalum, and P. curatellifolia leaf extracts could be potential sources of natural antioxidants. 1. Introduction Oxidation in living organisms is essential for the generation of energy during catabolism but these metabolic processes result in the continuous production of free radicals and reactive oxygen species (ROS) in vivo. Free radicals or more generally ROS are highly reactive species that are gener- ated by cells during respiration and cell-mediated immune functions [1]. Free radicals are also generated through envi- ronmental pollutants, cigarette smoke, automobile exhaust, radiation, and pesticides [2]. Te instability and reactivity of free radicals due to the lone electron in the outer shell can cause them to attack specifc biomolecules in the body such as protein and lipids [3]. Normally, there is a balance between the quantity of free radicals generated in the body and the antioxidant mechanisms which scavenge/quench these free radicals preventing them from causing deleterious efects in the body [2]. Te antioxidant mechanisms include endogenous and exogenous systems such as catalase and vitamin antioxidants, respectively. When the generation of free radicals exceeds the scavenging capacity of the cell’s endogenous systems, the excess free radicals seek stability through electron pairing with biological macromolecules of healthy cells such as proteins, lipids, and DNA. Te pairing of the free radicals with biomolecules can eventually result in the induction of lipid peroxidation which leads to cancer, atherosclerosis, cardiovascular diseases, ageing, and infammatory diseases [2, 4]. Prolonged oxidative stress can result in permanent damage to vital body organs, which could eventually lead to chronic disorders such as heart diseases, diabetes, cirrhosis, malaria, neurodegenerative dis- eases, AIDS, cancer, and premature aging [3, 5]. It has been Hindawi Publishing Corporation Journal of Food Processing Volume 2014, Article ID 918018, 7 pages http://dx.doi.org/10.1155/2014/918018