Optimal ammonium-nitrate ratio improves polyphenol content, antioxidant activities and nutrient accumulation in methanolic extracts of anthurium

Anthurium is herbaceous genus of the Araceae family possessing significant medicinal values. The leaves were subjected to methanol extraction and further evaluated for their potential phytochemicals and antioxidants. Nutrient solution with high concentrations of NO3− resulted in taller plants, bigger leaf area, higher plant biomass and more photosynthetic content. The total phenolic content was determined by using the Folin-Ciocalteu assay and the plants supplied with the 25:75 ratio of NH4+:NO3 − hydroponic solution accumulated maximum total phenolcontent (20.57±2.50 mg GAE/g FW). Antioxidant activity was calculated based on diphenyl picryl hydrazyl radicalscavenging ability with highest antioxidant potential DPPH (0.88±0.40 IC50 mg/g) in 100:0 ratios of NH4+:NO3 (IC50 232.90 mg/g). Total flavonoid content was measured by the aluminium chloride colorimetric assay method in which plants treated with 25:75 ratio of NH4+:NO3− yielded maximum flavonoid content (38.51±1.08 mg QE/g dry weight) whereas 0:100 ratio of NH4+:NO3− nutrition accumulated maximum flavonol content (33.60±2.63 mg QE/g dry weight). The leaves from plants supplied with 100:0 ratio of NH4+:NO3− hydroponic solution yielded maximum sugar content (31.235±7.05 mg/g). High concentration of ammonium significantly exhibited greater amounts of antioxidant activity. However, plants with only NO3− nutrition showed a lower P and K accumulationthan other treatments whilst highest N, Ca and Mg was observed with 25:75 ratios of NH4+:NO3−. A balanced NH4+:NO3− ratio (e.g., 25:75 or 50:50) contributes to improved morphological traits, antioxidant capacity and phytochemical content in anthurium.