Effect of compost and NPK fertilizer on improving biochemical and antioxidant properties of Moringa oleifera

Organic and inorganic fertilizers play a significant role in improving the nutritional quality of Moringa plant (Moringa oleifera). A field experiment of six treatments (control; 5 t/ha Compost; 120 kg/ha NPK; 50 + 50%/ha (NPK + Compost); 10 + 50%/ha (NPK + Compost); and 50 + 10%/ha (NPK + Compost) with three replications was conducted in a randomized complete block design in order to evaluate the effect of the application of compost and NPK fertilizer in various combinations on the biochemical and antioxidant potential of the Moringa plant. The results showed a significant influence of the compost and NPK fertilizer in various combination on the biochemical and antioxidant properties of the plant. Higher amount of carbohydrate, phenolic and flavonoid contents (406.24, 45.23 and 1.69 mg g− 1 dry wt., respectively) were observed in the plant treated with 50 + 50%/ha (NPK + Compost). Protein content (27.91 mg g− 1 dry wt.) was improved by the application of 120 kg/ha NPK fertilizer. The antioxidant properties such as, DPPH, ABTS and nitric oxide were analyzed as percentage scavenging and half maximal effective concentration (EC50) whereas ferric-reducing antioxidant potential (FRAP) was determined in terms of absorbance at 700 nm and EC0.50. The half maximal effective concentrations in combined application of NPK and compost (50 + 50%/ha (NPK + Compost)) were the lowest among the fertilizer treatments, resulting in EC50 value of 27.61, 17.18, 104.24 μg mL− 1 for DPPH, ABTS and nitric oxide assays, respectively whereas in case of the FRAP assay the EC0.50 value as found out to be 292.35 μg mL− 1.