Evaluation of antioxidant capacity and nutritional components of Five locally consumed fruits in Eastern Nigeria

Abstract

The nutraceutical richness of locally cultivated fruits in Eastern Nigeria remains poorly documented, limiting guidance for dietary management of oxidative stress-related disorders. This study quantified the vitamin C content, total flavonoids, total antioxidants, and reducing properties of five commonly consumed fruits: cashew (Anacardium occidentale), star apple (Chrysophyllum albidum), pawpaw (Carica papaya), garden egg (Solanum melongena), and watermelon (Citrullus lanatus). Spectroscopic methods were employed to assay total antioxidants, flavonoids, and reducing properties using gallic acid, rutin, and trichloroacetic acid as standards, respectively, while vitamin C was determined by titrimetric analysis using 2,6-dichlorophenol indophenol. Results (mean ± SD, mg/100 g) showed that pawpaw had the highest vitamin C (98.50 ± 0.01), total flavonoids (103.11 ± 0.01), total antioxidants (109.17 ± 0.04), and reducing properties (63.23 ± 0.07), followed by star apple, watermelon, garden egg, and cashew. A strong positive correlation (r = 0.87) was observed between total flavonoid content and reducing power, indicating that flavonoids significantly contribute to antioxidant activity. These findings provide evidence supporting increased consumption of pawpaw, star apple, and watermelon to mitigate oxidative stress, compensate for nutrient deficiencies, and promote public health in Eastern Nigeria.