Effect of Organic and Inorganic Sources of Nutrients on the Bioactive Compounds and Antioxidant Activity of Tomato

The study was conducted to compare the levels of bioactive compounds and antioxidant activities of (Solanum lycopersicum var. cerasiforme) fruits cultivated on different soil amendments (cow dung, chicken droppings and ([40 g/kg N: 60 g/kg N: 40 g/kg N] Nitrogen-Phosphorus-Potassium) in a shaded house. Tomato seedlings were transplanted into pre-treated soils and watered daily in the afternoon for a period of five months. The general growth and yield performances were in the order of NPK > Chicken droppings > Cow dung. The fruits were harvested at maturity (red-ripened stage) and subjected to bioactive compounds analysis using High Performance Liquid Chromatography (HPLC). The results of the study showed strong relationship between the level of macronutrients like nitrogen, phosphorus and potassium in the soil and the level phenolics, flavonoids, beta-carotene and lycopene contents in tomato. The level of beta-carotene was significantly higher (p < 0.05) in the fruits cultivated in the NPK amended soil which was totally different to the result of other bioactive compounds like phenolics, flavonoids, and lycopene which recorded their highest concentrations in the fruits harvested from control and cow dung amended soil. Antioxidant activity was determined by adding 2,2-diphenyl-1picrylhydrazyl to an aliquot of methanolic extract. The ability to scavenge radical was measured by reading the decrease in purple coloration of the solution using Ultraviolet-Visible (UV) Spectrophotometer. The tomato fruit from cow dung showed highest percentage of radical scavenging activities.