Evaluation of Antioxidant Potentialities of Whole Fruit Juices from Ximenia americana Linn., Vitex doniana Sweet. and Annona senegalensis Pers

Abstract

Ximenia americana Linn. (Olacaceae)., Vitex doniana Sweet. (Verbenaceae) and Annona senegalensis Pers. (Annonaceae) are three endemic fruit species growing in dry African savannahs. The fruits produced by these species have unique and highly appreciated organoleptic characteristics (aromas and flavors). However, their consumption is limited to the localities where they are found. In addition, the rarity of scientific information on their technological and nutritional potentials constitute an obstacle to their valorization. To bridge this gap, a comparative evaluation of the antioxidant potential of the whole fruit juices from these species was carried out. After physicochemical characterization of the fruits, anti-radical power and reducing activity of the juices were determined using DPPH, ABTS, FRAP and TAC methods. The physicochemical analyses of A. senegalensis indicated values of 7.65 ± 0.99 % (proteins), 32.81 ± 1.08 % (total sugars), 3.98 ± 0.17 % (ash) in opposite to 5.68 ± 0.17 (proteins), 42.45 ± 1.54 % (total sugars), 2.03 ± 0.2 % (ash) of X. americana and 2.97 ± 0.74 % (proteins), 33.62 ± 1.79 % (total sugars), 1.36 ± 0.19 % (ash) of V. doniana. The A. senegalensis juice had the highest total phenolic and flavonoid contents respectively 1.22 ± 0.01 and 0.36 ± 0.03 g/100 g of FW compared to X. americana (731.93 ± 2.25 and 295.58 ± 1.67 g/100 g respectively) and V. doniana (633.18 ± 1.93 and 111.09 ± 2.44 respectively). A. senegalensis and X. americana had the highest anti-radical activities by DPPH (12.50 ± 0.01) compared to V. donianaand vitamin C standard (8.33 ± 0.02). The ABTS test for the juices from V. doniana and A. senegalensis (14.28 ± 0.01) was compared to X. Americana (9.90 ± 0.01) and vitamin C standard (6.66 ± 0.02). Juices from X. americana had the highest TAC reducing capacity (570.67 ± 1.14 mg EAA / 100 g of FW) compared to V. doniana (521.15 ± 1.93) and A. senegalensis (147.78 ± 2.75). The FRAP test indicated values of 1401.04 ± 1.82 mg/100 g of FW in opposite to X. americana (798.79 ± 1.51) and V. doniana (600.19 ± 2.37). Flavonoids are strongly correlated to antioxidant activity by FRAP (r=0.86) and DPPH (r = 0.96). Tannins (r = 0.98) are strongly correlated with the TAC test.