Original Article EVALUATION OF FREE RADICAL SCAVENGING ABILITY AND ANTIRADICAL ACTIVITIES OF XIMENIA CAFFRA FRUIT EXTRACTS AT DIFFERENT RIPENING STAGES PENSIA E. MAPUNDA 1,2* , COSMAS MLIGO 2 , HERBERT V. M. LYARUU 2 1 Department of Conservation Biology, University of Dodoma, Tanzania, 2 Received: 11 Aug 2018 Revised and Accepted: 13 Nov 2018 Department of Botany, University of Dar es Salam, Tanzania Email: pensiamapundaa@yahoo.com ABSTRACT Objective: To evaluate the free radical scavenging ability and antiradical activities of Ximenia caffra fruit extracts in their different ripening stages. Methods: Using standard procedures, Ximenia caffra fruit extracts were determined for ferrous ions chelating ability, nitric oxide and hydroxyl radical scavenging ability. Antiradical activities were assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) in which the fruit extracts were evaluated for the number of antiradical units (AU515 ), the number of antiradical units per 1 mg of extracts (EAU515 ) and the total number of antiradical units per 1g of raw fruits (TAU515 Results: The fruit extracts exhibited significant higher ferrous ion chelating and free radical scavenging capacity compared to synthetic antioxidants (standard). Fruit extracts in early ripening stage (ERS) exhibited stronger ion chelation, nitric oxide and hydroxyl radical scavenging ability with low effective fruit extract concentration required to reduce free radicals by 50% (EC ). 50) that were 14, 25 and 30µg/ml respectively than the late ripening stage (LRS) extracts. The fruit extracts also showed high AU515 , EAU515 and TAU515 . The values of AU515 ranged from 0.93 to 0.95, while EAU515 from 78.30 to 79.34 and TAU515 Conclusion: Based on these observations Ximenia caffra is potentially beneficial to human health due to its strong ability to scavenge free radicals. Its utilization can potentially reduce the risk of degenerative diseases to human beings. ranged from 19762.46 to 23821.23 of the extracts in LRS and ERS respectively. Keywords: Antiradical activities, Iron chelation, Radical scavenging, Ripening stages, Ximenia caffra © 2019 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/) DOI: http://dx.doi.org/10.22159/ijpps.2019v11i1.29065 INTRODUCTION Free radicals are constantly generated in the human body during the oxidation process. Oxygen is an essential element, particularly in the production of adenosine triphosphate (ATP) which provides energy for cellular functioning. However, during the process several by-products are generated as free radicals [1]. The free radicals have been implicated in many human diseases including accelerated ageing, cancer, cardiovascular diseases, neurodegenerative disease and inflammation. These deleterious effects result from an imbalanced body process of free radicals production and removal that leads to their excessive accumulation such that the bodily defenses fail to prevent oxidative damage [2, 3]. Consumption of food rich in antioxidants promotes body defense systems by keeping the amount of the free radicals balanced [4]. However the use of synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) that are widely used in the food industry has been associated with harmful effects on human health, like liver damage and carcinogenesis [5, 6]. In consequence, public attention has been focused on natural antioxidants from plant materials as an alternative. Ximenia caffra is a wild fruit tree of the family Olacaceae native to Tanzania, Kenya, Malawi, Mozambique, South Africa, Uganda and Zambia. It grows in dry woodland and wooded grassland, often on rocky hillsides [7, 8]. The fruits from the tree are picked and eaten raw after ripening, and refreshing juice can be prepared by squeezing fruits in water and adding sugar [7, 9]. It has been reported that X. caffra has a potential medicinal use by the local communities. The leaves are used as a remedy for malaria, coughs, toothache, stomach-ache, ulcers and hookworm while roots are also used as a cure for infertility, mental illness, bilharzia, scorpion bites, menstrual problems, anaemia, hernia and intestinal worms [9, 10]. Several studies confirmed that large numbers of medicinal plants are also good free radical scavengers [11-13]. Previous research reported that extracts from leaf and seed of X. caffra have a good number of polyphenol compounds including phenolic acid and flavonoids with strong antioxidant capacity [9, 14]. Such information is limited in the fruit extracts and this article aimed to unveil the antioxidant potential of X. caffra fruits by evaluating their ability to scavenge free radicals and antiradical capacity. The study also determined the optimum fruit phase with a strong antioxidant capacity between the early and late fruit ripening stages. This is because the antioxidant ability is highly correlated with the concentration of phytonutrients that also change with the fruit ripening process [15-17]. MATERIALS AND METHODS Chemicals and reagents Methanol, ferric chloride, ferrozine, ethylene diamine tetraacetic acid (EDTA) sodium, nitroprusside, sulfanilamide, naphthylethylene- diamine dihydrochloride, hydrogen peroxide, potassium phosphate, potassium hydroxide, Collection and preparation of fruit samples 1, 1-diphenly-2-picrylhdrazyl (DPPH) ascorbic acid, catechin, and ethyl acetate procured from Sigma–Aldrich Co. (Germany). Fresh fruits of X. Caffra were collected from miombo woodlands of theTunduru District (Latitude: 10.932125 °N and Longitude: 37.238597 °E and Altitude: 686m) of Ruvuma Region Tanzania in February 2017. The plant was botanically authenticated by Curator Mr. Frank Mbago of Botany Department Herbarium, University of Dar es Salaam and voucher specimen N0: 20 dated 23/02/2017 was deposited in the Herbarium Department of Botany, University of Dar es Salaam, Tanzania for future reference. Ripe fruits were picked directly from the trees and stored as two different batches. The first batch was for those fruits which were at their early ripening stage (ERS) determined by their bright pink color and second batch were those with deep pink color observed at the late ripening stage (LRS). Samples were then packed in a cooler facility and transported to the Botany Department Laboratory University of Dar es Salaam. In the laboratory, each batch was stored as a dry, pulverized sample and frozen fresh until further analysis. International Journal of Pharmacy and Pharmaceutical Sciences ISSN- 0975-1491 Vol 11, Issue 1, 2019